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Sample records for molds casting

  1. MOLDS FOR CASTING PLUTONIUM

    DOEpatents

    Anderson, J.W.; Miley, F.; Pritchard, W.C.

    1962-02-27

    A coated mold for casting plutonium comprises a mold base portion of a material which remains solid and stable at temperatures as high as the pouring temperature of the metal to be cast and having a thin coating of the order of 0.005 inch thick on the interior thereof. The coating is composed of finely divided calcium fluoride having a particle size of about 149 microns. (AEC)

  2. Gating of Permanent Molds for ALuminum Casting

    SciTech Connect

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang

    2004-03-30

    This report summarizes a two-year project, DE-FC07-01ID13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings.

  3. 8. VIEW OF A MOLD FOR PRECISION CASTING. THE MOLD ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. VIEW OF A MOLD FOR PRECISION CASTING. THE MOLD WAS USED IN FOUNDRY OPERATIONS THAT CAST PLUTONIUM EITHER AS INGOTS SUITABLE FOR ROLLING AND FURTHER WROUGHT PROCESSING OR INTO SHAPES AMENABLE TO DIRECT MACHINING OPERATIONS. (5/6/59) - Rocky Flats Plant, Plutonium Fabrication, Central section of Plant, Golden, Jefferson County, CO

  4. Molding procedure for casting a variety of alloys

    NASA Technical Reports Server (NTRS)

    Fontes, M. J.; Kourtides, D.; Leibfritz, E. R.

    1970-01-01

    General procedure and molding sand composition for preparing molds usable for casting variety of alloys are developed. Molds are prepared from mixture of sand, sodium silicate binder, and organic liquid ester. Castings of radiographic quality are produced from various alloys.

  5. Mold For Casting Radius-Inspection Specimens

    NASA Technical Reports Server (NTRS)

    Ball, Robert N.

    1988-01-01

    Thin replicas viewed on comparator without sectioning. New mold machined from piece of transparent poly(methyl methacrylate). Fits around base of post. Two slots machined into inner surface form channels for casting inspection sections. Bottom of mold fits flush against surface around bottom of post. When surface slanted, mold automatically aligns in proper orientation. Time required to inspect elliptical radii located at bottoms of series of small posts reduced from 18 hours to 3 hours.

  6. Influence of mold length and mold heat transfer on horizontal continuous casting of nonferrous alloy rods

    NASA Astrophysics Data System (ADS)

    Verwijs, J. P.; Weckman, D. C.

    1988-04-01

    The influence of mold length and mold heat transfer on the conventional hot-top D.C. continuous casting process was studied through numerical simulations and experiments with horizontally cast 20 mm diameter lead and zinc rods. The minimum casting speed was found to be a nonlinear function of the mold length. For short molds, an inverse relationship between mold length and minimum casting speed was observed. However, the minimum casting speed for zinc cast from molds longer than 12 mm was constant at 2.5 mm/s. For lead cast in molds longer than 12 mm, the minimum observed casting speed was constant at 4.0 mm/s. The observed nonlinear relationship between minimum casting speed and mold length was predicted using a numerical model of the process. For this, an analytical expression for the mold boundary conditions was derived which included the influence of gas gap formation between the rod and the mold due to thermoelastic deformations of both the rod and the mold. Correlation between observed and predicted behavior was demonstrated for both the lead and zinc rods. Maximum casting speed was observed to increase with increased mold length; however, this speed was found to be critically dependent on process attributes such as mold and pinch wheel alignment and mold lubrication.

  7. Gating of Permanent Molds for Aluminum Casting

    SciTech Connect

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang

    2004-01-01

    This report summarizes a two-year project, DE-FC07-011D13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was to determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings. Equipment and procedure for real time X-Ray radiography of molten aluminum flow into permanent molds have been developed. Other studies have been conducted using water flow and behavior of liquid aluminum in sand mold using real time photography. This investigation utilizes graphite molds transparent to X-Rays making it possible to observe the flow pattern through a number of vertically oriented grating systems. These have included systems that are choked at the base of a rounded vertical sprue and vertical gating systems with a variety of different ingates into the bottom of a mold cavity. These systems have also been changed to include gating systems with vertical and horizontal gate configurations. Several conclusions can be derived from this study. A sprue-well, as designed in these experiments, does not eliminate the vena contracta. Because of the swirling at the sprue-base, the circulating metal begins to push the entering metal stream toward the open runner mitigating the intended effect of the sprue-well. Improved designs of

  8. Relationship Between Casting Distortion, Mold Filling, and Interfacial Heat Transfer in Sand Molds

    SciTech Connect

    J. K. Parker; K. A. Woodbury; T. S. Piwonka; Y. Owusu

    1999-09-30

    This project sought to determine the relationship between casting dimensions and interfacial heat transfer in aluminum alloy sand castings. The program had four parts; measurement of interfacial heat transfer coefficients in resin bonded and green sand molds, the measurement of gap formation in these molds, the analysis of castings made in varying gatings, orientations and thicknesses, and the measurement of residual stresses in castings in the as-cast and gate removed condition. New values for interfacial heat transfer coefficients were measured, a novel method for gap formation was developed, and the variation of casting dimensions with casting method, gating, and casting orientation in the mold was documented.

  9. Titanium casting: the surface reaction layer of castings obtained using ultra-low-temperature molds.

    PubMed

    Kikuchi, H; Onouchi, M; Hsu, H C; Kurotani, T; Nishiyama, M

    2001-03-01

    To examine whether the surface reaction layer of titanium castings can be reduced by lowering the mold temperature during casting, we cast titanium at three mold temperatures, including an ultra-low temperature produced by cooling the mold with liquid nitrogen, then measured the tensile strength and elongation of the castings. The titanium was cast using a centrifugal casting machine, and the molds were incinerated according to the manufacturers' instructions. Castings were then made with the molds at 200 degrees C, 600 degrees C, and an ultra-low temperature (-196 degrees C). The castability of titanium cast in the mold at the ultra-low temperature was good. The Vickers hardness near the surface layer of castings decreased as the mold temperature decreased. PMID:11383633

  10. New methods and materials for molding and casting ice formations

    NASA Technical Reports Server (NTRS)

    Reehorst, Andrew L.; Richter, G. Paul

    1987-01-01

    This study was designed to find improved materials and techniques for molding and casting natural or simulated ice shapes that could replace the wax and plaster method. By utilizing modern molding and casting materials and techniques, a new methodology was developed that provides excellent reproduction, low-temperature capability, and reasonable turnaround time. The resulting casts are accurate and tough.

  11. Experimental Determination of Heat Transfer Within the Metal/Mold Gap in a DC Casting Mold: Part II. Effect of Casting Metal, Mold Material, and Other Casting Parameters

    NASA Astrophysics Data System (ADS)

    Prasad, Arvind; Bainbridge, Ian F.

    2013-07-01

    Extensive experimental studies were conducted to quantify the effect of different parameters that can affect the heat transfer from the metal to the mold during the steady-state phase of DC casting. In the first part previously published, the experimental technique was established and results were reported for the effect of gas type (atmosphere within the mold) and the gap between the metal and the mold. The results showed the significant effect of gas thermal conductivity and the metal-mold gap on the mold wall heat transfer coefficient. In this second publication on heat transfer in the mold wall region of a DC casting mold, the results from the effect of casting temperature, gas flow rate, casting alloy, mold material, and the mold insert material on the mold wall heat transfer coefficient are described. The experiments reported in the current paper show that these additional factors tested do not affect the heat flux through the mold wall to the same extent as the gap size or the gas type. The heat transfer coefficient changes by less than 5 pct when casting temperature is changed by ±25 K, less than 15 pct when the gas flow rate within the metal-mold gap flows at up to 3 LPM, and approximately 30 pct when the mold material is changed from stainless steel to AA601 to copper. Similar results were obtained when different insert materials were used. These results are explained with the help of an electrical analogy of heat transfer and are consistent with the heat transfer theory.

  12. Method and mold for casting thin metal objects

    DOEpatents

    Pehrson, Brandon P; Moore, Alan F

    2014-04-29

    Provided herein are various embodiments of systems for casting thin metal plates and sheets. Typical embodiments include layers of mold cavities that are oriented vertically for casting the metal plates. In some embodiments, the mold cavities include a beveled edge such that the plates that are cast have a beveled edge. In some embodiments, the mold cavities are filled with a molten metal through an open horizontal edge of the cavity. In some embodiments, the mold cavities are filled through one or more vertical feed orifices. Further disclosed are methods for forming a thin cast metal plate or sheet where the thickness of the cast part is in a range from 0.005 inches to 0.2 inches, and the surface area of the cast part is in a range from 16 square inches to 144 square inches.

  13. View of foundrymen casting ingot molds; The flames from the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of foundrymen casting ingot molds; The flames from the mold in the center-right of the photo are present immediately after the pour has been completed - Bethlehem Steel Corporation, South Bethlehem Works, Iron Foundry, Along Lehigh River, North of Fourth Street, West of Minsi Trail Bridge, Bethlehem, Northampton County, PA

  14. Integrally cored ceramic investment casting mold fabricated by ceramic stereolithography

    NASA Astrophysics Data System (ADS)

    Bae, Chang-Jun

    Superalloy airfoils are produced by investment casting (IC), which uses ceramic cores and wax patterns with ceramic shell molds. Hollow cored superalloy airfoils in a gas turbine engine are an example of complex IC parts. The complex internal hollow cavities of the airfoil are designed to conduct cooling air through one or more passageways. These complex internal passageways have been fabricated by a lost wax process requiring several processing steps; core preparation, injection molding for wax pattern, and dipping process for ceramic shell molds. Several steps generate problems such as high cost and decreased accuracy of the ceramic mold. For example, costly tooling and production delay are required to produce mold dies for complex cores and wax patterns used in injection molding, resulting in a big obstacle for prototypes and smaller production runs. Rather than using separate cores, patterns, and shell molds, it would be advantageous to directly produce a mold that has the casting cavity and the ceramic core by one process. Ceramic stereolithography (CerSLA) can be used to directly fabricate the integrally cored ceramic casting mold (ICCM). CerSLA builds ceramic green objects from CAD files from many thin liquid layers of powder in monomer, which are solidified by polymerization with a UV laser, thereby "writing" the design for each slice. This dissertation addresses the integrally cored casting ceramic mold (ICCM), the ceramic core with a ceramic mold shell in a single patternless construction, fabricated by ceramic stereolithography (CerSLA). CerSLA is considered as an alternative method to replace lost wax processes, for small production runs or designs too complex for conventional cores and patterns. The main topic is the development of methods to successfully fabricate an ICCM by CerSLA from refractory silica, as well as related issues. The related issues are the segregation of coarse fused silica powders in a layer, the degree of segregation parameter to

  15. Mold with improved core for metal casting operation

    DOEpatents

    Gritzner, Verne B.; Hackett, Donald W.

    1977-01-01

    The present invention is directed to a mold containing an improved core for use in casting hollow, metallic articles. The core is formed of, or covered with, a layer of cellular material which possesses sufficient strength to maintain its structural integrity during casting, but will crush to alleviate the internal stresses that build up if the normal contraction during solidification and cooling is restricted.

  16. Grain Refinement of Permanent Mold Cast Copper Base Alloys

    SciTech Connect

    M.Sadayappan; J.P.Thomson; M.Elboujdaini; G.Ping Gu; M. Sahoo

    2005-04-01

    Grain refinement is a well established process for many cast and wrought alloys. The mechanical properties of various alloys could be enhanced by reducing the grain size. Refinement is also known to improve casting characteristics such as fluidity and hot tearing. Grain refinement of copper-base alloys is not widely used, especially in sand casting process. However, in permanent mold casting of copper alloys it is now common to use grain refinement to counteract the problem of severe hot tearing which also improves the pressure tightness of plumbing components. The mechanism of grain refinement in copper-base alloys is not well understood. The issues to be studied include the effect of minor alloy additions on the microstructure, their interaction with the grain refiner, effect of cooling rate, and loss of grain refinement (fading). In this investigation, efforts were made to explore and understand grain refinement of copper alloys, especially in permanent mold casting conditions.

  17. ''Heat Transfer at the Mold-Metal Interface in Permanent Mold Casting of Aluminum Alloys'' Final Project Report

    SciTech Connect

    Professor R. D. Pehlke, Principal Investigator, Dr. John M. Cookson, Dr. Shouwei Hao, Dr. Prasad Krishna, Kevin T. Bilkey

    2001-12-14

    This project on heat transfer coefficients in metal permanent mold casting has been conducted in three areas. They are the theoretical study at the University of Michigan, the experimental investigation of squeeze casting at CMI-Tech Center (Now Hayes-Lemmerz Technical Center) and the experimental investigation of low pressure permanent mold casting at Amcast Automotive.

  18. System for control of electroslag casting in a collar mold

    SciTech Connect

    McEnerney , J.W.; Dewey, B.R.; Hutton, J.T.; David, S.A.

    1980-01-01

    This report describes the initial development of an electroslag casting control system. The main emphasis of our work and the results reported herein deal with the attempts to develop techniques for locating and controlling the liquid slag-metal interface. Thermocouples embedded in the mold wall provide a simple but accurate means for locating the interface.

  19. Application of statistical methods for analyzing the relationship between casting distortion, mold filling, and interfacial heat transfer in sand molds

    SciTech Connect

    Y. A. Owusu

    1999-03-31

    This report presents a statistical method of evaluating geometric tolerances of casting products using point cloud data generated by coordinate measuring machine (CMM) process. The focus of this report is to present a statistical-based approach to evaluate the differences in dimensional and form variations or tolerances of casting products as affected by casting gating system, molding material, casting thickness, and casting orientation at the mold-metal interface. Form parameters such as flatness, parallelism, and other geometric profiles such as angularity, casting length, and height of casting products were obtained and analyzed from CMM point cloud data. In order to relate the dimensional and form errors to the factors under consideration such as flatness and parallelism, a factorial analysis of variance and statistical test means methods were performed to identify the factors that contributed to the casting distortion at the mold-metal interface.

  20. Casting inorganic structures with DNA molds

    PubMed Central

    Sun, Wei; Boulais, Etienne; Hakobyan, Yera; Wang, Wei Li; Guan, Amy; Bathe, Mark; Yin, Peng

    2014-01-01

    We report a general strategy for designing and synthesizing inorganic nanostructures with arbitrarily prescribed three-dimensional shapes. Computationally designed DNA strands self-assemble into a stiff “nano-mold” that contains a user-specified three-dimensional cavity and encloses a nucleating gold “seed”. Under mild conditions, this seed grows into a larger cast structure that fills and thus replicates the cavity. We synthesized a variety of nanoparticles with three nanometer resolution: three distinct silver cuboids with three independently tunable dimensions, silver and gold nanoparticles with diverse cross sections, and composite structures with homo-/heterogeneous components. The designer equilateral silver triangular and spherical nanoparticles exhibited plasmonic properties consistent with electromagnetism-based simulations. Our framework is generalizable to more complex geometries and diverse inorganic materials, offering a range of applications in biosensing, photonics, and nanoelectronics. PMID:25301973

  1. Reusable molds for casting U-Zr alloys

    SciTech Connect

    Chen, P.S.; Stevens, W.C. ); Trybus, C.L. )

    1992-09-01

    Refractory oxides, carbides, nitrides and sulfides were examined as mold coating materials for use in casting nuclear fuel. The molds require excellent high temperature chemical and mechanical stability combined with reasonable room temperature ductility to allow for fuel removal. Coatings were applied onto quartz and refractory metal coupons using various techniques. Sessile drop tests employing molten U-10%Zr (by weight) at 1550[degrees]C were used to characterize coating performance. Results indicate that NbC, TiN, and Y[sub 2]O[sub 3] were non-wetting with U-10%Zr. However, only the Y[sub 2]O[sub 3] coating completely prevented adhesion of the fuel. The paper describes coating methods and details of the sessile drop experiments.

  2. Reusable molds for casting U-Zr alloys

    SciTech Connect

    Chen, P.S.; Stevens, W.C.; Trybus, C.L.

    1992-09-01

    Refractory oxides, carbides, nitrides and sulfides were examined as mold coating materials for use in casting nuclear fuel. The molds require excellent high temperature chemical and mechanical stability combined with reasonable room temperature ductility to allow for fuel removal. Coatings were applied onto quartz and refractory metal coupons using various techniques. Sessile drop tests employing molten U-10%Zr (by weight) at 1550{degrees}C were used to characterize coating performance. Results indicate that NbC, TiN, and Y{sub 2}O{sub 3} were non-wetting with U-10%Zr. However, only the Y{sub 2}O{sub 3} coating completely prevented adhesion of the fuel. The paper describes coating methods and details of the sessile drop experiments.

  3. Mold Simulator Study of the Initial Solidification of Molten Steel in Continuous Casting Mold: Part II. Effects of Mold Oscillation and Mold Level Fluctuation

    NASA Astrophysics Data System (ADS)

    Zhang, Haihui; Wang, Wanlin

    2016-04-01

    The surface quality of the continuous casting strands is closely related to the initial solidification of liquid steel in the vicinity of the mold meniscus, and thus the clear understanding of the behavior of molten steel initial solidification would be of great importance for the control of the quality of final slab. With the development of the mold simulator techniques, the complex interrelationship between the solidified shell surface profile, heat flux, shell thickness, mold level fluctuation, and the infiltrated slag film was well illustrated in our previous study. As the second part, this article investigated the effect of the mold oscillation frequency, stroke, and mold level fluctuation on the initial solidification of the molten steel through the conduction of five different experiments. Results suggested that in the case of the stable mold level, the oscillation marks (OMs) exhibit equally spaced horizon depressions on the shell surface, where the heat flux at the meniscus area raises rapidly during negative strip time (NST) period and the presence of each OMs on the shell surface is corresponding to a peak value of the heat flux variation rate. Otherwise, the shell surface is poorly defined by the existence of wave-type defects, such as ripples or deep depressions, and the heat flux variation is irregular during NST period. The rising of the mold level leads to the longer-pitch and deeper OMs formation; conversely, the falling of mold level introduces shorter-pitch and shallower OMs. With the increase of the mold oscillation frequency, the average value of the low-frequency heat flux at the meniscus increases; however, it decreases when the mold oscillation stroke increases. Additionally, the variation amplitude of the high-frequency temperature and the high-frequency heat flux decreases with the increase of the oscillation frequency and the reduction of the oscillation stroke.

  4. A Review of Mold Flux Development for the Casting of High-Al Steels

    NASA Astrophysics Data System (ADS)

    Wang, Wanlin; Lu, Boxun; Xiao, Dan

    2016-02-01

    Mold flux plays key roles during the continuous casting process of molten steel, which accounts for the quality of final slabs. With the development of advanced high strength steels (AHSS), certain amounts of Al have been added into steels that would introduce severe slag/metal interaction problems during process of continuous casting. The reaction is between Al and SiO2 that is the major component in the mold flux system. Intensive efforts have been conducted to optimize the mold flux and a CaO-Al2O3-based mold flux system has been proposed, which shows the potential to be applied for the casting process of AHSS. The latest developments for this new mold flux system were summarized with the aim to offer technical guidance for the design of new generation mold flux system for the casting of AHSS.

  5. Study on Type C Coal Fly ash as an Additive to Molding Sand for Steel Casting

    NASA Astrophysics Data System (ADS)

    Palaniappan, Jayanthi

    2016-05-01

    Study of physio-chemical properties studies such as granulometric analysis, moisture, X ray fluorescence etc. were performed with Type C coal—combustion fly ash to investigate their potential as a distinct option for molding sand in foundry, thereby reducing the dependency on latter. Technological properties study such as compressive strength, tensile strength, permeability and compaction of various compositions of fly ash molding sand (10, 20 and 30 % fly ash substitute to chemically bonded sand) were performed and compared with silica molding sand. Steel casting production using this fly ash molding sand was done and the casting surface finish and typical casting parameters were assessed. It was noted that a good quality steel casting could be produced using type C fly ash molding sand, which effectively replaced 20 % of traditional molding sand and binders thereby providing greater financial profits to the foundry and an effective way of fly ash utilization (waste management).

  6. Characterization of Ni-Cr alloys using different casting techniques and molds.

    PubMed

    Chen, Wen-Cheng; Teng, Fu-Yuan; Hung, Chun-Cheng

    2014-02-01

    This study differentiated the mechanical properties of nickel-chromium (Ni-Cr) alloys under various casting techniques (different casting molds and casting atmospheres). These techniques were sampled by a sand mold using a centrifugal machine in ambient air (group I) and electromagnetic induction in an automatic argon castimatic casting machine (group II). The specimen casting used a graphite mold by a castimatic casting machine (group III). The characteristics of the Ni-Cr alloys, yield and ultimate tensile strength, bending modulus, microhardness, diffraction phase, grindability, ability to spring back, as well as ground microstructure and pattern under different casting conditions were evaluated. The group III specimens exhibited the highest values in terms of strength, modulus, hardness, and grindability at a grind rate of 500 rpm. Moreover, group III alloys exhibited smaller grain sizes, higher ability to spring back, and greater ductility than those casted by sand investment (groups I and II). The main factor, "casting mold," significantly influenced all mechanical properties. The graphite mold casting of the Ni-Cr dental alloys in a controlled atmosphere argon casting system provided an excellent combination of high mechanical properties and good ability to spring back, and preserved the ductile properties for application in Ni-Cr porcelain-fused system. The results can offer recommendations to assist a prosthetic technician in selecting the appropriate casting techniques to obtain the desired alloy properties. PMID:24411373

  7. Permanent Mold Casting of JIS-AC4C Aluminum Alloy Using a Low-Temperature Mold

    SciTech Connect

    Yamagata, Hiroshi; Nikawa, Makoto

    2011-01-17

    Permanent mold casting using mold temperatures below 200 deg. C was conducted to obtain a high-strength, thin-walled casting. Al-7.36 mass% Si -0.18 Cu- 0.27Mg-0.34Fe alloy JIS-AC4C was cast using a bottom pouring cast plan. The product had a rectangular tube shape (70 mm W x 68 mm D x 180 mm H) with wall thicknesses of 1, 3 and 5 mm. The effect of heat insulation at the melt path was compared when using a sand runner insert and when using a steel runner insert as well as a powder mold release agent. Fine microstructures were observed in the casting. The smaller the thickness, the higher the hardness with smaller secondary dendrite arm spacing (SDAS). However, the hardness and the SDAS were unaffected by the mold temperature. It was proposed that the avoidance of the formation of primary {alpha} dendrite at the melt path generates a higher strength casting with adequate mold filling.

  8. Permanent Mold Casting of JIS-AC4C Aluminum Alloy Using a Low-Temperature Mold

    NASA Astrophysics Data System (ADS)

    Yamagata, Hiroshi; Nikawa, Makoto

    2011-01-01

    Permanent mold casting using mold temperatures below 200° C was conducted to obtain a high-strength, thin-walled casting. Al-7.36 mass% Si -0.18 Cu- 0.27Mg-0.34Fe alloy JIS-AC4C was cast using a bottom pouring cast plan. The product had a rectangular tube shape (70 mm W x 68 mm D x 180 mm H) with wall thicknesses of 1, 3 and 5 mm. The effect of heat insulation at the melt path was compared when using a sand runner insert and when using a steel runner insert as well as a powder mold release agent. Fine microstructures were observed in the casting. The smaller the thickness, the higher the hardness with smaller secondary dendrite arm spacing (SDAS). However, the hardness and the SDAS were unaffected by the mold temperature. It was proposed that the avoidance of the formation of primary α dendrite at the melt path generates a higher strength casting with adequate mold filling.

  9. Investigation of Heat Transfer at the Mold/Metal Interface in Permanent Mold Casting of Light Alloys

    SciTech Connect

    Robert D. Pehlke; John T. Berry

    2005-12-16

    Accurate modeling of the metal casting process prior to creating a mold design demands reliable knowledge of the interfacial heat transfer coefficient at the mold metal interface as a function of both time and location. The phenomena concerned with the gap forming between the mold and the solidifying metal are complex but need to be understood before any modeling is attempted. The presence of mold coatings further complicates the situation. A commercial casting was chosen and studied in a gravity permanent mold casting process. The metal/mold interfacial heat transfer coefficient (IHTC) was the focus of the research. A simple, direct method has been used to evaluate the IHTC. Both the simulation and experiments have shown that a reasonably good estimate of the heat transfer coefficient could be made in the case studied. It has been found that there is a good agreement between experiments and simulations in the temperature profiles during the solidification process, given that the primary mechanism of heat transfer across the gap in permanent mold casting of light alloys is by conduction across the gap. The procedure utilized to determine the interfacial heat transfer coefficient can be applied to other casting processes. A recently completed project involving The University of Michigan and Mississippi State University, together with several industrial partners, which was supported by the USDOE through the Cast Metals Coalition, examined a number of cases of thermal contact. In an investigation which gave special consideration to the techniques of measurement, several mold coatings were employed and results presented as a function of time. Realistic conditions of coating thickness and type together with an appropriate combination of mold preheat and metal pouring temperature were strictly maintained throughout the investigation. Temperature sensors, in particular thermocouples, play an important part in validating the predictions of solidification models. Cooling

  10. Increasing the life of molds for casting copper and its alloys

    NASA Astrophysics Data System (ADS)

    Smirnov, A. N.; Spiridonov, D. V.

    2010-12-01

    The work of the molds intended for casting copper and copper alloys in semicontinuous casters for producing flat billets is considered. It is shown that, to increase the resistance of mold plates, the inner space of the mold should have a taper shape toward the casting direction and take into account the shrinkage of the linear dimensions of the ingot during its motion in the mold. The taper shape increases the intensity and uniformity of heat removal due to close contact between the ingot and the mold inner surface. Testing of new design molds under industrial conditions demonstrates that their resistance increases by a factor of 4.0-4.5. The taper effect of the mold plates is much more pronounced in their narrow faces.

  11. Application of High-Temperature Mold Materials to Die Cast Copper Motor Rotor for Improved Efficiency

    SciTech Connect

    John G. Cowie; Edwin F. Brush, Jr.; Dale T. Peters; Stephen P. Midson; Darryl J. Van Son

    2003-05-01

    The objective of the study, Application of High-Temperature Mold Materials to Die Cast Copper Motor Rotor for Improved Efficiency, was to support the Copper Development Association (CDA) in its effort to design, fabricate and demonstrate mold technologies designed to withstand the copper motor rotor die casting environment for an economically acceptable life. The anticipated result from the compiled data and tests were to: (1) identify materials suitable for die casting copper, (2) fabricate motor rotor molds and (3) supply copper rotor motors for testing in actual compressor systems. Compressor manufacturers can apply the results to assess the technical and economical viability of copper rotor motors.

  12. Castability and surface hardness of titanium cast plates obtained from experimental phosphate-bonded silica investment molds.

    PubMed

    Takahashi, J; Zhang, J Z; Okazaki, M

    1993-12-01

    The effect of 12 different experimental compositions of phosphate-bonded SiO2 investments was examined on cast pure titanium. The mold temperature was 600 degrees C and the casting was conducted with an argon-arc melting and pressure casting machine. Castability was evaluated by the volume of casting porosity, which was calculated from the volume of wax pattern (15 mm x 15 mm x 1.5 mm), the weight of cast plate and the specific density of pure titanium. The existence of inner casting porosities was confirmed by an X-ray non-destructive inspection instrument. Cast plates made in molds with cristobalite had significantly lower castability and higher surface hardness than those in molds with quartz as a refractory material. Cast plates in molds (quartz-cristobalite mixtures) with 20% binder had lower surface hardness and fewer casting porosities than those in molds with 10% binder. PMID:8004919

  13. Control of solidification boundary in continuous casting by asymmetric cooling and mold offset

    NASA Technical Reports Server (NTRS)

    Siegel, R.

    1985-01-01

    A solution, developed to obtain solidification-interface shapes for complex situations in which both the ingot cooling and mold geometry are asymmetric, is analyzed. The effect of mold offsett and of unequal ingot side temperatures on the interface shapes is illustrated in graphs. The results of the analysis show how the solidification interface in continuous casting can be controlled by asymmetries in both mold geometry and cooling of the ingot sides.

  14. 40 CFR Table 5 to Subpart Wwww of... - Alternative Organic HAP Emissions Limits for Open Molding, Centrifugal Casting, and SMC...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... during spinning and cure are considered to be closed molding and are not subject to any emissions limit. Centrifugal casting operations where the mold is not vented during spinning and cure, and the resin is applied... apply. 4 Centrifugal casting operations where the mold is vented during spinning and the resin...

  15. Development of a Mold Cracking Simulator: The Study of Breakout and Crack Formation in Continuous Casting Mold

    NASA Astrophysics Data System (ADS)

    Zhang, Yexin; Wang, Wanlin; Zhang, Haihui

    2016-08-01

    Based on the mold simulator technology, a mold-cracking simulator has been successfully developed to study the process of breakout and the shell surface crack formation during the initial solidification of molten steel inside the continuous casting mold. First, a spheroidal protrusion was installed on the mold hot surface to mimic the abnormal force that generated by mold wall deformation, and then the external force was applied to the initial solidified shell, to facilitate the formation of breakout and shell surface cracks. Second, the responding temperature and heat flux across mold hot surface were recovered by an inverse heat conduction problem. The experimental results indicated that the mold breakout occurs around the shell tip by the combined efforts from external horizontal force, ferrostatic pressure, and thermal stresses during positive strip time. The breakout tends to introduce the peak of the responding temperature and heat flux across the mold hot surface. The vertical propagation velocity of the rupture point in the solidification shell has been calculated as 0.42 m/s in this study, which is in good agreement with industrial slabs. The paper also suggested that surface transverse crack formation is related to the segregation of sulfur during the initial solidification of molten steel.

  16. Development of a Mold Cracking Simulator: The Study of Breakout and Crack Formation in Continuous Casting Mold

    NASA Astrophysics Data System (ADS)

    Zhang, Yexin; Wang, Wanlin; Zhang, Haihui

    2016-06-01

    Based on the mold simulator technology, a mold-cracking simulator has been successfully developed to study the process of breakout and the shell surface crack formation during the initial solidification of molten steel inside the continuous casting mold. First, a spheroidal protrusion was installed on the mold hot surface to mimic the abnormal force that generated by mold wall deformation, and then the external force was applied to the initial solidified shell, to facilitate the formation of breakout and shell surface cracks. Second, the responding temperature and heat flux across mold hot surface were recovered by an inverse heat conduction problem. The experimental results indicated that the mold breakout occurs around the shell tip by the combined efforts from external horizontal force, ferrostatic pressure, and thermal stresses during positive strip time. The breakout tends to introduce the peak of the responding temperature and heat flux across the mold hot surface. The vertical propagation velocity of the rupture point in the solidification shell has been calculated as 0.42 m/s in this study, which is in good agreement with industrial slabs. The paper also suggested that surface transverse crack formation is related to the segregation of sulfur during the initial solidification of molten steel.

  17. Energy Saving Melting and Revert Reduction Technology (Energy-SMARRT): Light Metals Permanent Mold Casting

    SciTech Connect

    Fasoyinu, Yemi

    2014-03-31

    Current vehicles use mostly ferrous components for structural applications. It is possible to reduce the weight of the vehicle by substituting these parts with those made from light metals such as aluminum and magnesium. Many alloys and manufacturing processes can be used to produce these light metal components and casting is known to be most economical. One of the high integrity casting processes is permanent mold casting which is the focus of this research report. Many aluminum alloy castings used in automotive applications are produced by the sand casting process. Also, aluminum-silicon (Al-Si) alloys are the most widely used alloy systems for automotive applications. It is possible that by using high strength aluminum alloys based on an aluminum-copper (Al-Cu) system and permanent mold casting, the performance of these components can be enhanced significantly. This will also help to further reduce the weight. However, many technological obstacles need to be overcome before using these alloys in automotive applications in an economical way. There is very limited information in the open literature on gravity and low-pressure permanent mold casting of high strength aluminum alloys. This report summarizes the results and issues encountered during the casting trials of high strength aluminum alloy 206.0 (Al-Cu alloy) and moderate strength alloy 535.0 (Al-Mg alloy). Five engineering components were cast by gravity tilt-pour or low pressure permanent mold casting processes at CanmetMATERIALS (CMAT) and two production foundries. The results of the casting trials show that high integrity engineering components can be produced successfully from both alloys if specific processing parameters are used. It was shown that a combination of melt processing and mold temperature is necessary for the elimination of hot tears in both alloys.

  18. Analysis of emissions collected from four types of iron casting molds

    SciTech Connect

    Palmer, W.G.; James, R.H.; Moorman, W.J.

    1985-12-01

    The levels of polycyclic aromatic hydrocarbons (PAH) and related compounds, phenols and particulates were determined in emissions collected from iron casting molds composed of four different types of chemical binders: furan, urethane, green sand with sea coal and phenol-formaldehyde resins in shell molds. The shell sample, with 50% particulates, contained the most water-soluble material; green sand, 25% particulates; furan, 10% particulates; and urethane, less than 2% particulate material. The portion of the particulate fraction soluble in cyclohexane varies from 16 to 36% between mold types; emissions from urethane and furan molds contained the lowest quantities of cyclohexane-soluble components and of PAH and related compounds. Phenol, which was found in all four foundry samples, was present in the highest concentration in emissions from urethane molds. Shell mold emissions contained the highest levels of 2- and 4-nitrophenol.

  19. Operation of molds and mandrels during electroslag casting of hollow billets

    NASA Astrophysics Data System (ADS)

    Volokhonskii, L. A.; Kuznetsov, L. N.; Kissel'Man, M. A.; Demidov, V. A.; Pavlova, N. P.; Polovinkin, V. N.

    2007-12-01

    One method of electroslag casting is the remelting of a metallic consumable electrode in a short movable mold as they move toward each other. The main advantages of this method are the saving of copper required to make the mold, a decrease in the electric-furnace height, and a decrease in energy consumption. The most important disadvantage of this method is the erosion of the mold and mandrel copper walls. The wear of the mold’s copper walls depends on the electric current through the mold and the specific surface power released in the slag bath-mold wall contact zone. The erosion-induced fracture of the movable mold and mandrel cannot be fully avoided during electroslag casting; however, the wear (fracture) rate can be reduced using several measures. A procedure is proposed for calculation of a rational geometry of the broadened portion of the movable mold in order to estimate the electrical parameters and the wear resistance of the equipment designed for the electroslag casting of hollow steel billets.

  20. Casting/mold thermal contact heat transfer during solidification of Al-Cu-Si alloy (LM 21) plates in thick and thin molds

    NASA Astrophysics Data System (ADS)

    Prabhu, K. Narayan; Chowdary, Bheemappa; Venkataraman, N.

    2005-10-01

    Heat flow at the casting/mold interface was assessed and studied during solidification of Al-Cu-Si (LM 21) alloy in preheated cast iron molds of two different thicknesses, coated with graphite and alumina based dressings. The casting and the mold were instrumented with thermocouples connected to a computer controlled temperature data acquisition system. The thermal history at nodal locations in the mold and casting obtained during experimentation was used to estimate the heat flux by solving the one-dimensional inverse heat conduction problem. The cooling rate and solidification time were measured using the computer-aided cooling curve analysis data. The estimated heat flux transients showed a peak due to the formation of a stable solid shell, which has a higher thermal conductivity compared with the liquid metal in contact with the mold wall prior to the occurrence of the peak. The high values of heat flux transients obtained with thin molds were attributed to mold distortion due to thermal stresses. For thin molds, assumption of Newtonian heating yielded reliable interfacial heat transfer coefficients as compared with one-dimensional inverse modeling. The time of occurrence of peak heat flux increased with a decrease in the mold wall thickness and increase in the casting thickness.

  1. Method of making an apertured casting. [using duplicate mold

    NASA Technical Reports Server (NTRS)

    Terray, A. (Inventor)

    1976-01-01

    An apertured casting is made by first forming a duplicate in the shape of the finished casting, positioning refractory metal bodies such as wires in the duplicate at points corresponding to apertures or passageways in finished products, forming a ceramic coating on the duplicate, removing the duplicate material, firing the ceramic in a vacuum or inert atmosphere, vacuum casting the metal in the ceramic form, removing the ceramic form, heating the cast object in an atmospheric furnace to oxidize the refractory metal bodies and then leaching the oxidized refractory bodies from the casting with a molten caustic agent or acid solution.

  2. Molds for electroslag casting systems. [2-1/4 Cr-1 Mo steel, 9 Cr-1 Mo steel

    SciTech Connect

    Bhat, G.K.

    1985-07-01

    This report describes the basic types of molds used for the manufacture of electroslag castings. The report also provides guidelines for the design of such molds based on heat generation and heat transfer considerations pertaining to the electroslag casting process. The designs of the two-step and three-step molds used for the manufacture of electroslag castings of 2-1/4 Cr-1 Mo steel, 316 stainless steel and 9 Cr-1 Mo steel are provided as examples of cost effective mold construction using cooled copper liners for metal-slag containment. 5 refs., 12 figs.

  3. Development of Metal Casting Molds By Sol-Gel Technology Using Planetary Resources

    NASA Technical Reports Server (NTRS)

    Sibille, L.; Sen, S.; Curreri, P.; Stefanescu, D.

    2000-01-01

    Metals extracted from planetary soils will eventually need to be casted and shaped in-situ to produce useful products. In response to this challenge, we propose to develop and demonstrate the manufacturing of a specific product using Lunar and Martian soil simulants, i.e. a mold for the casting of metal and alloy parts, which will be an indispensable tool for the survival of outposts on the Moon and Mars. Drawing from our combined knowledge of sol-gel and metal casting technologies, we set out to demonstrate the extraordinary potential of mesoporous materials such as aerogels to serve as efficient casting molds as well as fulfilling numerous other needs of an autonomous planetary outpost.

  4. Permanent mold casting of titanium alloy Ti-6Al-4V

    SciTech Connect

    Sadayappan, M.; Sahoo, M.; Lavender, C.; paul.jablonski, P.D.

    2008-01-01

    A literature review indicated that data on the effect of various casting defects, such as inclusions and porosity, on the properties of titanium alloy castings were not readily available. This information is required to reduce the cost of fabricating titanium castings for potential automotive applications. To this end, a research project was initiated to develop data on the as-cast properties of titanium alloy Ti-6Al-4V (Ti64). Step plate castings with 3.2, 6.3, 13, and 25 mm thick steps were produced in a high-density graphite mold following melting in an induction furnace with water-cooled copper hearth. The mechanical properties were determined in the as-cast condition and were found to be close to the values reported in standards. Few casting defects such as inclusions and porosity were observed, and the loss of strength due to these defects is not significant. It is shown that titanium castings with good mechanical properties can be produced in high-density graphite molds.

  5. Determination of the Heat Transfer Coefficient at the Metal-Mold Interface During Centrifugal Casting

    NASA Astrophysics Data System (ADS)

    Vacca, Santiago; Martorano, Marcelo A.; Heringer, Romulo; Boccalini, Mário

    2015-05-01

    The heat transfer coefficient at the metal-mold interface ( h MM) has been determined for the first time during the centrifugal casting of a Fe-C alloy tube using the inverse solution method. To apply this method, a centrifugal casting experiment was carried out to measure cooling curves within the tube wall under a mold rotation speed of 900 rpm, imposing a centrifugal force 106 times as large as the gravity force (106 G). As part of the solution method, a comprehensive heat transfer model of the centrifugal casting was also developed and coupled to an optimization algorithm. Finally, the evolution of h MM with time that gives the minimum squared error between measured and calculated cooling curves was obtained. The determined h MM is approximately 870 W m-2 K-1 immediately after melt pouring, decreasing to about 50 W m-2 K-1 when the average temperature of the tube is ~973 K (700 °C), after the end of solidification. Despite the existence of a centrifugal force that could enhance the metal-mold contact, these values are lower than those generally reported for static molds with or without an insulating coating at the mold inner surface. The implemented model shows that the heat loss by radiation is dominant over that by convection at the tube inner surface, causing the formation of a solidification front that meets another front coming from the outer surface of the tube.

  6. Dimensional Accuracy of Stone Casts Obtained with Multiple Pours into the Same Mold

    PubMed Central

    Valente, Valdimar da Silva; Zanetti, Artêmio Luiz; Feltrin, Pedro Paulo; Inoue, Ricardo Tatsuo; de Moura, Carmem Dolores Vilarinho Soares; Pádua, Luiz Evaldo de Moura

    2012-01-01

    Aim. The aim of the present study was to compare the dimensional accuracy of stone casts obtained with vinyl polysiloxane molds through the double-impression technique with three pours into the same mold. Methods. A stainless steel master model was constructed simulating a three-unit fixed prosthesis. Twelve impressions were taken of this master model with addition silicone, using the double-impression technique. Three pours of type IV gypsum were then made into each mold, thus producing 36 casts. The pours were made 1 hour, 6 hours and 24 hours after the impression procedure. Next, intra- and interabutment measurements were made in a coordinate measuring machine. Results. Comparative analysis of the dimensional accuracy of stone casts resulting from multiple pours was not statistically significant in pours first and second (P > 0.05). These values, however, were statistically significant at third pour in the height in abutment 1 and upper distance interabutment. Conclusion. The wait time (1 hour, and 6 hours) observed before pouring the stone into the same molds did not cause significant dimensional accuracy of the casts. PMID:23320186

  7. 40 CFR Appendix - Alternative Organic HAP Emissions Limits for Open Molding, Centrifugal Casting, and SMC...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 13 2012-07-01 2012-07-01 false Alternative Organic HAP Emissions Limits for Open Molding, Centrifugal Casting, and SMC Manufacturing Operations Where the Standards Are Based on a 95 Percent Reduction Requirement Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED)...

  8. 40 CFR Appendix - Alternative Organic HAP Emissions Limits for Open Molding, Centrifugal Casting, and SMC...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 13 2013-07-01 2012-07-01 true Alternative Organic HAP Emissions Limits for Open Molding, Centrifugal Casting, and SMC Manufacturing Operations Where the Standards Are Based on a 95 Percent Reduction Requirement Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED)...

  9. 40 CFR Appendix - Alternative Organic HAP Emissions Limits for Open Molding, Centrifugal Casting, and SMC...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 12 2011-07-01 2009-07-01 true Alternative Organic HAP Emissions Limits for Open Molding, Centrifugal Casting, and SMC Manufacturing Operations Where the Standards Are Based on a 95 Percent Reduction Requirement Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED)...

  10. 40 CFR Appendix - Alternative Organic HAP Emissions Limits for Open Molding, Centrifugal Casting, and SMC...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Alternative Organic HAP Emissions Limits for Open Molding, Centrifugal Casting, and SMC Manufacturing Operations Where the Standards Are Based on a 95 Percent Reduction Requirement Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED)...

  11. Improvement of internal quality of continuously cast slabs by introducing consumable vibrating macrocoolers in a mold

    NASA Astrophysics Data System (ADS)

    Golenkov, M. A.

    2014-12-01

    The methods of controlling metal solidification by introducing consumable internal macrocoolers in the form of strips, wires, and powders are considered. The effect of this technology on the structure of continuously cast slabs is described. The results of full-scale experiments on the introduction of a steel strip as a macrocooler into the molds of continuous casters of various types are presented.

  12. Improvements in Sand Mold/Core Technology: Effects on Casting Finish

    SciTech Connect

    Prof. John J. Lannutti; Prof. Carroll E. Mobley

    2005-08-30

    In this study, the development and impact of density gradients on metal castings were investigated using sand molds/cores from both industry and from in-house production. In spite of the size of the castings market, almost no quantitative information about density variation within the molds/cores themselves is available. In particular, a predictive understanding of how structure and binder content/chemistry/mixing contribute to the final surface finish of these products does not exist. In this program we attempted to bridge this gap by working directly with domestic companies in examining the issues of surface finish and thermal reclamation costs resulting from the use of sand molds/cores. We show that these can be substantially reduced by the development of an in-depth understanding of density variations that correlate to surface finish. Our experimental tools and our experience with them made us uniquely qualified to achieve technical progress.

  13. Influence of FC-Mold on the Full Solidification of Continuous Casting Slab

    NASA Astrophysics Data System (ADS)

    Wang, Qiangqiang; Zhang, Lifeng

    2016-03-01

    A three-dimensional model coupling fluid flow, heat transfer, solidification for slab continuous casting process with flow control mold (FC-Mold) was constructed. The full solidification process from the meniscus to the solidification end of slab was obtained for the first time. The calculation domain was designed according to the actual dimension of the continuous caster. The main results show that the calculated flow speed on the meniscus at different casting speeds and the calculated shell profile had a good agreement with the measured flow speed using nail board measurement and the shell with breakout. The application of FC-Mold could improve the symmetry of flow in width, and suppress the formation of vortices on the meniscus. The decrease of upper magnetic field intensity of FC-Mold reduced the washing effect on the solidifying front, and favored the shell growth in the mold region. In the secondary cooling zone, the shell thickness increased gradually, and the shell grew quickly at the final stage of solidification for the whole mushy form of steel. In addition, FC-Mold had an effect on the shape and position of the solidification end.

  14. Molds

    MedlinePlus

    ... touching mold or mold spores may cause allergic reactions or asthma attacks in sensitive people. Molds can cause fungal infections. In addition, mold exposure may irritate your eyes, skin, nose, ...

  15. Experimental and numerical study of the effect of mold vibration on aluminum castings alloys

    NASA Astrophysics Data System (ADS)

    Abu-Dheir, Numan

    2005-07-01

    The recent advances in scientific and engineering tools have allowed researchers to integrate more science into manufacturing, leading to improved and new innovative processes. As a result, important accomplishments have been reached in the area of designing and engineering new materials for various industrial applications. This subject is of critical significance because of the impact it could have on the manufacturing industry. In the casting industry, obtaining the desired microstructure and properties during solidification may reduce or eliminate the need for costly thermo-mechanical processing prior to secondary manufacturing processes. Several techniques have been developed to alter and control the microstructure of castings during solidification including semi-solid processing, electromagnetic stirring, electromagnetic vibration, and mechanical vibration. Although it is established that mold vibration can significantly influence the structure and properties of castings, however, most of the studies are generally qualitative, limited to a small range of conditions and no attempts have been made to simulate the effect of vibration on casting microstructure. In this work, a detailed experimental and numerical investigation is carried out to advance the utilization of mold vibration as an effective tool for controlling and modifying the casting microstructure. The effects of a wide range of vibration amplitudes and frequencies on the solidification kinetics, microstructure formation and mechanical properties of Al-Si alloys are examined. Results show strong influence of mold vibration on the resulting casting. The presence of porosity was significantly reduced as a result of mold vibration. In addition, the changes in microstructure and mechanical properties can be successfully represented by the changes in solidification characteristics. Increasing the vibration amplitude tends to reduce the lamellar spacing and change the silicon morphology to become more

  16. Control of Crystal Morphology for Mold Flux During High-Aluminum AHSS Continuous Casting Process

    NASA Astrophysics Data System (ADS)

    GUO, Jing; SEO, Myung-Duk; SHI, Cheng-Bin; CHO, Jung-Wook; KIM, Seon-Hyo

    2016-05-01

    In the present manuscript, the efforts to control the crystal morphology are carried out aiming at improving the lubrication of lime-alumina-based mold flux for casting advanced high-strength steel with high aluminum. Jackson α factors for crystals of melt crystallization in multi-component mold fluxes are established and reasonably evaluated by applying thermodynamic databases to understand the crystal morphology control both in lime-alumina-based and lime-silica-based mold fluxes. The results show that Jackson α factor and supercooling are the most critical factors to determine the crystal morphology in a mold flux. Crystals precipitating in mold fluxes appear with different morphologies due to their different Jackson α factors and are likely to be more faceted with higher Jackson α factor. In addition, there is a critical supercooling degree for crystal morphology dendritic transition. When the supercooling over the critical value, the crystals transform from faceted shape to dendritic ones in morphology as the kinetic roughening occurs. Typically, the critical supercooling degrees for cuspidine dendritic transition in the lime-silica-based mold fluxes are evaluated to be between 0.05 and 0.06. Finally, addition of a small amount of Li2O in the mold flux can increase the Jackson α factor and decrease the supercooling for cuspidine precipitation; thus, it is favorable to enhance a faceted cuspidine crystal.

  17. Control of Crystal Morphology for Mold Flux During High-Aluminum AHSS Continuous Casting Process

    NASA Astrophysics Data System (ADS)

    GUO, Jing; SEO, Myung-Duk; SHI, Cheng-Bin; CHO, Jung-Wook; KIM, Seon-Hyo

    2016-08-01

    In the present manuscript, the efforts to control the crystal morphology are carried out aiming at improving the lubrication of lime-alumina-based mold flux for casting advanced high-strength steel with high aluminum. Jackson α factors for crystals of melt crystallization in multi-component mold fluxes are established and reasonably evaluated by applying thermodynamic databases to understand the crystal morphology control both in lime-alumina-based and lime-silica-based mold fluxes. The results show that Jackson α factor and supercooling are the most critical factors to determine the crystal morphology in a mold flux. Crystals precipitating in mold fluxes appear with different morphologies due to their different Jackson α factors and are likely to be more faceted with higher Jackson α factor. In addition, there is a critical supercooling degree for crystal morphology dendritic transition. When the supercooling over the critical value, the crystals transform from faceted shape to dendritic ones in morphology as the kinetic roughening occurs. Typically, the critical supercooling degrees for cuspidine dendritic transition in the lime-silica-based mold fluxes are evaluated to be between 0.05 and 0.06. Finally, addition of a small amount of Li2O in the mold flux can increase the Jackson α factor and decrease the supercooling for cuspidine precipitation; thus, it is favorable to enhance a faceted cuspidine crystal.

  18. Analysis of Mold Friction in a Continuous Casting Using Wavelet Entropy

    NASA Astrophysics Data System (ADS)

    Yong, Ma; Fangyin, Wang; Cheng, Peng; Wei, Gui; Bohan, Fang

    2016-06-01

    By studying mold friction (MDF), we observed that monitoring and controlling of the friction between the strand and the mold is very important for continuous casting to improve lubrication and prevent breakout. However, existing analysis technologies of MDF do not support the continuous casting very well. In addition, we found that the wavelet entropy has multiscale and statistical properties. Informed by these observations, in this article, we use wavelet entropy to judge the lubrication state between the strand and the mold. First, we demonstrate the implementation and superiority of wavelet entropy and how it helps in efficient evaluation of the lubrication state in mold. A study of wavelet entropy of MDF, which is obtained from the abnormal continuous casting production, such as level fluctuation, submerged entry nozzle broken, and breakout, has been performed to achieve relevant conclusions. The results indicate that the information of MDF in time and frequency domains could be obtained simultaneously by the application of wavelet entropy and that the wavelet entropy has a good sensibility for the study of disorder of MDF, which could further reveal the nature of MDF.

  19. Monitoring of solidification in the continuous casting mold by temperature sensors

    NASA Astrophysics Data System (ADS)

    Pyszko, René; Příhoda, Miroslav; Čarnogurská, Mária

    2016-06-01

    Defects of continuously cast strand, such as unevenness of shell thickness or cracks as well as unstable casting parameters result in changes of strand surface temperature which affect heat flux and temperature field in the mold wall. Methods based on the principle of measurement and mathematical processing of temperatures in the mold wall are used for the purposes of diagnostics of the shell formation process, prediction of surface and subsurface quality and breakout danger, adjustment of the casting axis or condition monitoring of the oscillating mechanism. Measured values of temperatures in the wall depend on the exact position of the sensor in the wall, especially in the normal direction to the mold working surface. Ensuring the accurate and constant distance between the sensor and the mold surface is technically demanding; therefore it is necessary to correct the measured temperatures mathematically. The article describes two methods for correcting the measured temperatures, based on physical and statistical principles that have been developed and used in a real diagnostics system. Practical applications of the methods for diagnostics of strand surface quality and breakout prediction are presented.

  20. Application of heat pipe technology in permanent mold casting of nonferrous alloys

    NASA Astrophysics Data System (ADS)

    Elalem, Kaled

    The issue of mold cooling is one, which presents a foundry with a dilemma. On the one hand; the use of air for cooling is safe and practical, however, it is not very effective and high cost. On the other hand, water-cooling can be very effective but it raises serious concerns about safety, especially with a metal such as magnesium. An alternative option that is being developed at McGill University uses heat pipe technology to carry out the cooling. The experimental program consisted of designing a permanent mold to produce AZ91E magnesium alloy and A356 aluminum alloy castings with shrinkage defects. Heat pipes were then used to reduce these defects. The heat pipes used in this work are novel and are patent pending. They are referred to as McGill Heat Pipes. Computer modeling was used extensively in designing the mold and the heat pipes. Final designs for the mold and the heat pipes were chosen based on the modeling results. Laboratory tests of the heat pipe were performed before conducting the actual experimental plan. The laboratory testing results verified the excellent performance of the heat pipes as anticipated by the model. An industrial mold made of H13 tool steel was constructed to cast nonferrous alloys. The heat pipes were installed and initial testing and actual industrial trials were conducted. This is the first time where a McGill heat pipe was used in an industrial permanent mold casting process for nonferrous alloys. The effects of cooling using heat pipes on AZ91E and A356 were evaluated using computer modeling and experimental trials. Microstructural analyses were conducted to measure the secondary dendrite arm spacing, SDAS, and the grain size to evaluate the cooling effects on the castings. The modeling and the experimental results agreed quite well. The metallurgical differences between AZ91E and A356 were investigated using modeling and experimental results. Selected results from modeling, laboratory and industrial trials are presented. The

  1. Characterization of fold defects in AZ91D and AE42 magnesium alloy permanent mold castings

    SciTech Connect

    Bichler, L.; Ravindran, C.

    2010-03-15

    Casting premium-quality magnesium alloy components for aerospace and automotive applications poses unique challenges. Magnesium alloys are known to freeze rapidly prior to filling a casting cavity, resulting in misruns and cold shuts. In addition, melt oxidation, solute segregation and turbulent metal flow during casting contribute to the formation of fold defects. In this research, formation of fold defects in AZ91D and AE42 magnesium alloys cast via the permanent mold casting process was investigated. Computer simulations of the casting process predicted the development of a turbulent metal flow in a critical casting region with abrupt geometrical transitions. SEM and light optical microscopy examinations revealed the presence of folds in this region for both alloys. However, each alloy exhibited a unique mechanism responsible for fold formation. In the AZ91D alloy, melt oxidation and velocity gradients in the critical casting region prevented fusion of merging metal front streams. In the AE42 alloy, limited solubility of rare-earth intermetallic compounds in the {alpha}-Mg phase resulted in segregation of Al{sub 2}RE particles at the leading edge of a metal front and created microstructural inhomogeneity across the fold.

  2. Molds

    MedlinePlus

    Molds are fungi that can be found both outdoors and indoors. They grow best in warm, damp and humid conditions. If ... spots in your house, you will probably get mold. Molds can cause health problems. Inhaling or touching ...

  3. 40 CFR 63.5810 - What are my options for meeting the standards for open molding and centrifugal casting operations...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... subpart WWWW of 40 CFR part 63. If you are using an add-on control device to reduce HAP emissions, you... standards for open molding and centrifugal casting operations at new and existing sources? 63.5810 Section... Meeting Standards § 63.5810 What are my options for meeting the standards for open molding and...

  4. 40 CFR 63.5810 - What are my options for meeting the standards for open molding and centrifugal casting operations...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... subpart WWWW of 40 CFR part 63. If you are using an add-on control device to reduce HAP emissions, you... standards for open molding and centrifugal casting operations at new and existing sources? 63.5810 Section... § 63.5810 What are my options for meeting the standards for open molding and centrifugal...

  5. 40 CFR 63.5810 - What are my options for meeting the standards for open molding and centrifugal casting operations...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... subpart WWWW of 40 CFR part 63. If you are using an add-on control device to reduce HAP emissions, you... standards for open molding and centrifugal casting operations at new and existing sources? 63.5810 Section... Meeting Standards § 63.5810 What are my options for meeting the standards for open molding and...

  6. 40 CFR 63.5810 - What are my options for meeting the standards for open molding and centrifugal casting operations...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... subpart WWWW of 40 CFR part 63. If you are using an add-on control device to reduce HAP emissions, you... standards for open molding and centrifugal casting operations at new and existing sources? 63.5810 Section... Meeting Standards § 63.5810 What are my options for meeting the standards for open molding and...

  7. Development of Aerogel Molds for Metal Casting Using Lunar and Martian Regolith

    NASA Technical Reports Server (NTRS)

    2003-01-01

    In the last few years NASA has set new priorities for research and development of technologies necessary to enable long-term presence on the Moon and Mars. Among these key technologies is what is known as in situ resource utilization, which defines all conceivable usage of mineral, liquid, gaseous, or biological resources on a visited planet. In response to this challenge, we have been focusing on developing and demonstrating the manufacturing of a specific product using Lunar and Martian soil simulants (i.e., a mold for the casting of metal and alloy parts) which will be an indispensable tool for the survival of outposts on the Moon and Mars. In addition, our purpose is to demonstrate the feasibility of using mesoporous materials such as aerogels to serve as efficient casting molds for high quality components in propulsion and other aerospace applications. The first part of the project consists of producing aerogels from the in situ resources available in Martian and Lunar soil. The approach we are investigating is to use chemical processes to solubilize silicates using organic reagents at low temperatures and then use these as precursors in the formation of aerogels for the fabrication of metal casting molds. One set of experiments consists of dissolving silica sources in basic ethylene glycol solution to form silicon glycolates. When ground silica aerogel was used as source material, a clear solution of silicon glycolate was obtained and reacted to form a gel thus proving the feasibility of this approach. The application of this process to Lunar and Martian simulants did not result in the formation of a gel; further study is in progress. In the second method acidified alcohol is reacted with the simulants to form silicate esters. Preliminary results indicate the presence of silicon alkoxide in the product distillation. However, no gel has been obtained so further characterization is ongoing. In the second part of the project, the focus has been on developing a

  8. Effects of advanced oxidation on green sand properties via iron casting into green sand molds.

    PubMed

    Wang, Yujue; Cannon, Fred S; Voigt, Robert C; Komarneni, Sridhar; Furness, J C

    2006-05-01

    The effects of advanced oxidation (AO) processing on the properties of green sand were studied via pouring cast iron into green sand molds. Upon cooling, the green sand molds were autopsied at various distances from the metal-sand interface. Autopsy green sand samples collected from a mold that incorporated AO water were characterized and compared to controlled samples collected from a similar autopsied mold made with conventional tap water (TAP). It was found that the AO processing removed a coating of coal pyrolysis products from the clay surface that typically accumulated on the clay surface. As a result, the AO-conditioned green sand retained 10-15% more active clay as measured bythe standard ultrasonic methylene blue titration than did the TAP-conditioned green sand. The AO processing also nearly doubled the generation of activated carbon from the normalized amount of coal composition of the green sand during the casting process. The AO-enhanced activated carbon generation and the AO-incurred clay surface cleaning provided the AO-conditioned green sand with higher normalized pore volume, and thus higher normalized m-xylene adsorption capacity, i.e., relative to before-metal-pouring conditions. Furthermore, mathematical analysis indicated that the AO-conditioned green sand better retained its important properties after pouring than did the TAP-conditioned green sand. Effectively, this meant after metal pouring, the AO-conditioned sample offered about the same net properties as the TAP-conditioned sample, even though the AO-conditioned sample contained less clay and coal before metal pouring. These results conformed to the full-scale foundry empirical finding that when AO is used, foundries need less makeup clay and coal addition through each casting cycle, and they release less air emissions. PMID:16719117

  9. Numerical simulation on level fluctuation in bloom casting mold with electromagnetic stirring

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Ni, H. W.; Li, Y.; Zhao, Z. F.

    2016-03-01

    Based on a 380mm × 280mm bloom caster mold, the level fluctuation of steel-slag interface in the mold was simulated by the VOF model of commercial software Fluent. The effects of current intensity and frequency of EMS (electromagnetic stirring) on the level fluctuation in the mold were studied. The results show that whether or not with EMS, the maximum level fluctuation site of the mold occurs in the vicinity of the submerged entry nozzle. Compared with casting without EMS, molten steel flows horizontally rotatably under the action of the electromagnetic force by electromagnetic stirring, so the impact depth of molten steel decreases, then the level fluctuation slightly reduces, and the maximum level fluctuation value in the wide direction and the narrow direction of the mold, reduce from 4.24mm and 4.14mm to 4.04mm and 3.73mm respectively. With increasing intensity and frequency of current, the mold level fluctuation rises and the distribution uniformity of the level fluctuating amplitude worsens. The maximum level fluctuation enlarges by 0.18mm with raising the current intensity from 450A to 550A, but it enlarges by 0.79mm with 600A current intensity. The maximum level fluctuation enlarges by 0.15mm with raising the current frequency from 1.5Hz to 2.0Hz, but it quickly enlarges by 0.78mm with 2.5Hz current frequency. When the current strength and frequency are not more than 550A and 2.0Hz, level fluctuations are 4.00mm or less, which can meet requirements for controlling the bloom surface quality.

  10. Casting dimensional control and fatigue life prediction for permanent mold casting dies. Technical progress report, September 29, 1993-- September 30, 1994

    SciTech Connect

    1994-11-01

    First year efforts as part of a three year program to address metal casting dimensional control and fatigue life prediction for permanent mold casting dies are described. Procedures have been developed and implemented to collect dimensional variability data from production steel castings. The influence of process variation and casting geometry variables on dimensional tolerances have been investigated. Preliminary results have shown that these factors have a significant influence on dimensional variability, although this variability is considerably less than the variability indicated in current tolerance standards. Gage repeatability and reproducibility testing must precede dimensional studies to insure that measurement system errors are acceptably small. Also initial efforts leading to the development and validation of a CAD/CAE model to predict the thermal fatigue life of permanent molds for aluminum castings are described. An appropriate thermomechanical property database for metal, mold and coating materials has been constructed. A finite element model has been developed to simulate the mold temperature distribution during repeated casting cycles. Initial validation trials have indicated the validity of the temperature distribution model developed.

  11. Simulation of fluid flow induced by opposing ac magnetic fields in a continuous casting mold

    SciTech Connect

    Chang, F.C.; Hull, J.R.; Beitelman, L.

    1995-07-01

    A numerical simulation was performed for a novel electromagnetic stirring system employing two rotating magnetic fields. The system controls stirring flow in the meniscus region of a continuous casting mold independently from the stirring induced within the remaining volume of the mold by a main electromagnetic stirrer (M-EMS). This control is achieved by applying to the meniscus region an auxiliary electromagnetic field whose direction of rotation is opposite to that of the main magnetic field produced by the M-EMS. The model computes values and spatial distributions of electromagnetic parameters and fluid flow in the stirred pools of mercury in cylindrical and square geometries. Also predicted are the relationships between electromagnetics and fluid flows pertinent to a dynamic equilibrium of the opposing stirring swirls in the meniscus region. Results of the numerical simulation compared well with measurements obtained from experiments with mercury pools.

  12. Heat transfer at the mold-metal interface in permanent mold casting of aluminum alloys project. Quarterly project status report, January 1, 1998--March 31, 1998

    SciTech Connect

    Pehlke, R.D.; Hao, Shouwei; Cookson, J.M.

    1998-03-31

    There have been numerous developments in the current project over the last three months. The most appropriate geometries for performing the interfacial heat transfer studies have been discussed with both of our Industrial Partners. Both companies have molds which may be available for adaptation to record the thermal history during casting required for determining interfacial heat transfer coefficients. The details of what instrumentation would be the most appropriate remain to be worked out, but the instrumentation would likely include thermocoupling in the mold cavity as well as in the mold wall, as well as pressure sensors in the squeeze casting geometry molds and ultrasonic gap monitoring in the low pressure and gravity fed permanent mold geometry molds. The first advisory committee meeting was held on February 6th, and the steering committee was apprised of the objectives of the program. The capabilities of the Industrial Partners were reviewed, as well as the need for the project to make use of resources from other CMC projects. The second full Advisory Committee Meeting will be held in early May.

  13. Evaluation of the Inertness of Investment Casting Molds Using Both Sessile Drop and Centrifugal Casting Methods

    NASA Astrophysics Data System (ADS)

    Cheng, Xu; Yuan, Chen; Green, Nick; Withey, Paul

    2013-02-01

    The investment casting process is an economic production method for engineering components in TiAl-based alloys and offers the benefits of a near net-shaped component with a good surface finish. An investigation was undertaken to develop three new face coat systems based on yttria, but with better sintering properties. These face coat systems were mainly based on an yttria-alumina-zirconia system (Y2O3-0.5 wt pct Al2O3-0.5 wt pct ZrO2), an yttria-fluoride system (Y2O3-0.15 wt pct YF3), and an yttria-boride system (Y2O3-0.15 wt pct B2O3). After sintering, the chemical inertness of the face coat was first tested and analyzed using a sessile drop test through the metal wetting behavioral change for each face coat surface. Then, the interactions between the shell and metal were studied by centrifugal investment casting TiAl bars. Although the sintering aids in yttria can decrease the chemical inertness of the face coat, the thickness of the interaction layer in the casting was less than 10 μm; therefore, these face coats still can be possible face coat materials for investment casting TiAl alloys.

  14. Effects of Mold Temperature and Pouring Temperature on the Hot Tearing of Cast Al-Cu Alloys

    NASA Astrophysics Data System (ADS)

    Li, Shimin; Sadayappan, Kumar; Apelian, Diran

    2016-07-01

    The effects of mold temperature and pouring temperature on hot tearing formation and contraction behavior of a modified Al-Cu alloy 206 (M206) have been studied. The experiments were conducted using a newly developed Constrained Rod Mold, which simultaneously measures the contraction force/time/temperature during solidification for the restrained casting or linear contraction/time/temperature for a relaxed casting. Three mold temperatures [473 K, 573 K, and 643 K (200 °C, 300 °C, and 370 °C)] and three pouring temperatures [superheat of 50 K, 100 K, and 150 K (50 °C, 100 °C, and 150 °C)] were studied, and alloy A356 was used as reference for comparison. The results confirm that alloy A356 has high resistance to hot tearing. Hot tearing did not occur for the three mold temperatures evaluated, whereas alloy M206 exhibited significant hot tearing for the same casting and mold temperature conditions. Hot tearing severity and linear contraction in alloy 206 decreased significantly with increasing mold temperature. Increasing pouring temperature increases hot tearing in alloy M206, but the effect is not as significant as that of mold temperature. The results and underlying mechanism of these effects are discussed in correlation with the thermomechanical properties and microstructures.

  15. Determination of the heat transfer coefficient at the metal-sand mold interface of lost foam casting process

    NASA Astrophysics Data System (ADS)

    Zhang, Liqiang; Tan, Wenfang; Hu, Hao

    2016-06-01

    For modeling solidification process of casting accurately, a reliable heat transfer boundary condition data is required. In this paper, an inverse conduction model was established to determine the heat flux and heat transfer coefficient at the metal-sand mold interface for cylindrical casting in the lost foam process. The numerically calculated temperature was compared with analytic solution and simulation solution obtained by commercial software ProCAST to investigate the accuracy of heat conduction model. The instantaneous cast and sand mold temperatures were measured experimentally and these values were used to determine the interfacial heat transfer coefficient (IHTC). The IHTC values during lost foam casting were shown to vary from 20 to 800 W m-2 K-1. Additionally, the characteristics of the time-varying IHTC have also been discussed in this study.

  16. Solidification interface shape for continuous casting in an offset mold - Two analytical methods

    NASA Astrophysics Data System (ADS)

    Siegel, R.

    1984-02-01

    A solution method for finding the unknown solidification interface in manufacturing slab ingots as a continuous casting is presented, which involves a product solution in the potential plane and the use of conjugate harmonic functions. It is argued that the method may be more direct for some geometries than the Cauchy boundary value method. Moreover, the usefulness of the Cauchy boundary value method is demonstrated through the example of a nonsymmetric horizontal mold where the walls are offset to support the lower ingot boundary.

  17. Solidification interface shape for continuous casting in an offset mold - Two analytical methods

    NASA Technical Reports Server (NTRS)

    Siegel, R.

    1984-01-01

    A solution method for finding the unknown solidification interface in manufacturing slab ingots as a continuous casting is presented, which involves a product solution in the potential plane and the use of conjugate harmonic functions. It is argued that the method may be more direct for some geometries than the Cauchy boundary value method. Moreover, the usefulness of the Cauchy boundary value method is demonstrated through the example of a nonsymmetric horizontal mold where the walls are offset to support the lower ingot boundary.

  18. A Combined Experimental and Computational Approach for the Design of Mold Topography that Leads to Desired Ingot Surface and Microstructure in Aluminum Casting.

    SciTech Connect

    Dr. Zabaras, N.J.; Samanta, D.; Tan, L.

    2005-10-30

    A design methodology will be developed with which casting mold surface topographies can be tuned to produce required surface features and micro-structural properties of Aluminum ingots. Both static and continuous casting processes will be examined with instrumented molds. Mold surface topographies, which consist of unidirectional and bi-directional groove textures, will be generated using contact and non-contact techniques to elicit a radiator-like effect at the mold-casting interface. The rate of heat extraction, the evolution of near-surface cast microstructure, and shell macro-morphology can be controlled once the proper balance between mold surface area extension and the degree of imperfect wetting at the instant solidification starts is determined. Once this control is achieved, it will be possible to minimize or even eliminate costly post-casting surface milling or scalping which is currently a major barrier to the development of new Aluminum casting processes.

  19. Grain refinement of permanent mold cast copper base alloys. Final report

    SciTech Connect

    Sadayappan, M.; Thomson, J. P.; Elboujdaini, M.; Gu, G. Ping; Sahoo, M.

    2004-04-29

    Grain refinement behavior of copper alloys cast in permanent molds was investigated. This is one of the least studied subjects in copper alloy castings. Grain refinement is not widely practiced for leaded copper alloys cast in sand molds. Aluminum bronzes and high strength yellow brasses, cast in sand and permanent molds, were usually fine grained due to the presence of more than 2% iron. Grain refinement of the most common permanent mold casting alloys, leaded yellow brass and its lead-free replacement EnviroBrass III, is not universally accepted due to the perceived problem of hard spots in finished castings and for the same reason these alloys contain very low amounts of iron. The yellow brasses and Cu-Si alloys are gaining popularity in North America due to their low lead content and amenability for permanent mold casting. These alloys are prone to hot tearing in permanent mold casting. Grain refinement is one of the solutions for reducing this problem. However, to use this technique it is necessary to understand the mechanism of grain refinement and other issues involved in the process. The following issues were studied during this three year project funded by the US Department of Energy and the copper casting industry: (1) Effect of alloying additions on the grain size of Cu-Zn alloys and their interaction with grain refiners; (2) Effect of two grain refining elements, boron and zirconium, on the grain size of four copper alloys, yellow brass, EnviroBrass II, silicon brass and silicon bronze and the duration of their effect (fading); (3) Prediction of grain refinement using cooling curve analysis and use of this method as an on-line quality control tool; (4) Hard spot formation in yellow brass and EnviroBrass due to grain refinement; (5) Corrosion resistance of the grain refined alloys; (6) Transfer the technology to permanent mold casting foundries; It was found that alloying elements such as tin and zinc do not change the grain size of Cu-Zn alloys

  20. Casting Technology.

    ERIC Educational Resources Information Center

    Wright, Michael D.; And Others

    1992-01-01

    Three articles discuss (1) casting technology as it relates to industry, with comparisons of shell casting, shell molding, and die casting; (2) evaporative pattern casting for metals; and (3) high technological casting with silicone rubber. (JOW)

  1. Performance of U-Pu-Zr fuel cast into zirconium molds

    SciTech Connect

    Crawford, D.C.; Lahm, C.E. ); Tsai, H. )

    1992-10-01

    U-3Zr and U-20.5Pu-3Zr were injection cast into Zr tubes, or sheaths, rather than into quartz molds and clad in 316SS. These elements and standard-cast U-l0Zr and U-IgPu-l0Zr elements were irradiated in EBR-II to 2 at.% and removed for interim examination. Measurements of axial growth at indicate that the Zr-sheathed elements exhibited significantly less axial elongation than the standard-cast elements (1.3 to 1.8% versus 4.9 to 8.1%). Fuel material extruded through the ends of the Zr sheaths. allowing the low-Zr fuel to contact the cladding in some cases. Transverse metallographic sections reveal cracks in the Zr sheath through which fuel extruded and contacted cladding. The sheath is not a sufficient barrier between fuel and cladding to reduce FCCI. and any adverse effects due to increased FCCI will be evident as the elements attain higher burnup.

  2. 40 CFR 63.5810 - What are my options for meeting the standards for open molding and centrifugal casting operations...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true What are my options for meeting the standards for open molding and centrifugal casting operations at new and existing sources? 63.5810 Section 63.5810 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR...

  3. The research and development of CCD-based slab continuous casting mold copper surface imaging system

    NASA Astrophysics Data System (ADS)

    Wang, Xingdong; Zhang, Liugang; Xie, Haihua; Long, Liaosha; Yu, Wenyong

    2011-11-01

    An imaging system for the continuous casting mold copper surface is researched and developed, to replace the on-line manual measuring method, which is used to checking Copper defects such as wearing, scratches and coating loss and other phenomena. Method: The imaging system proposes a special optical loop formed by three Mirrors, selects light source, CCD camera and lens type, designs mechanical transmission system and installation platform. Result: the optical loop and light source can insure imaging large-format object in narrow space. The CCD camera and lens determine the accuracy of horizontal scanning, and the mechanical transmission system ensures accuracy of the vertical scan. The installation platform supplies base and platform for the system. Conclusions: CCD-based copper surface imaging system effectively prevent defects such as missed measuring and low efficiency, etc. It can automatically and accurately shoot copper surface images on-line, and supply basis for image processing, defects identification and copper changing in the late.

  4. Nondestructive method for chemically machining crucibles or molds from their enclosed ingots and castings

    DOEpatents

    Stout, Norman D.; Newkirk, Herbert W.

    1991-01-01

    An inventive method is described for chemically machining rhenium, rhenium and tungsten alloy, and group 5b and 6b crucibles or molds from included ingots and castings comprised of oxide crystals including YAG and YAG based crystals, garnets, corundum crystals, and ceramic oxides. A mixture of potassium hydroxide and 15 to 90 weight percent of potassium nitrate is prepared and maintained at a temperature above melting and below the lower of 500 degrees centigrade or the temperature of decomposition of the mixture. The enveloping metal container together with its included oxide crystal object is rotated within the heated KOH-KNO.sub.3 mixture, until the container is safely chemically machined away from the included oxide crystal object.

  5. A Simple Model of the Mold Boundary Condition in Direct-Chill (DC) Casting of Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Baserinia, Amir R.; Ng, H.; Weckman, D. C.; Wells, M. A.; Barker, S.; Gallerneault, M.

    2012-08-01

    An accurate thermofluids model of aluminum direct-chill (DC) casting must solve the heat-transfer equations in the ingot with realistic external boundary conditions. These boundary conditions are typically separated into two zones: primary cooling, which occurs inside the water-cooled mold, and secondary cooling, where a film of water contacts the ingot surface directly. Here, a simple model for the primary cooling boundary condition of the steady-state DC casting process was developed. First, the water-cooled mold was modeled using a commercial computational fluid dynamics (CFD) package, and its effective heat-transfer coefficient was determined. To predict the air-gap formation between the ingot and mold and to predict its effect on the primary cooling, a simple density-based shrinkage model of the solidifying shell was developed and compared with a more complex three-dimensional (3-D) thermoelastic model. DC casting simulations using these two models were performed for AA3003 and AA4045 aluminum alloys at two different casting speeds. A series of experiments was also performed using a laboratory-scale rectangular DC caster to measure the thermal history and sump shape of the DC cast ingots. Comparisons between the simulations and experimental results suggested that both models provide good agreement for the liquid sump profiles and the temperature distributions within the ingot. The density-based shrinkage model, however, is significantly easier to implement in a CFD code and is more computationally efficient.

  6. Large Eddy Simulation of Transient Flow, Solidification, and Particle Transport Processes in Continuous-Casting Mold

    NASA Astrophysics Data System (ADS)

    Liu, Zhongqiu; Li, Linmin; Li, Baokuan; Jiang, Maofa

    2014-07-01

    The current study developed a coupled computational model to simulate the transient fluid flow, solidification, and particle transport processes in a slab continuous-casting mold. Transient flow of molten steel in the mold is calculated using the large eddy simulation. An enthalpy-porosity approach is used for the analysis of solidification processes. The transport of bubble and non-metallic inclusion inside the liquid pool is calculated using the Lagrangian approach based on the transient flow field. A criterion of particle entrapment in the solidified shell is developed using the user-defined functions of FLUENT software (ANSYS, Inc., Canonsburg, PA). The predicted results of this model are compared with the measurements of the ultrasonic testing of the rolled steel plates and the water model experiments. The transient asymmetrical flow pattern inside the liquid pool exhibits quite satisfactory agreement with the corresponding measurements. The predicted complex instantaneous velocity field is composed of various small recirculation zones and multiple vortices. The transport of particles inside the liquid pool and the entrapment of particles in the solidified shell are not symmetric. The Magnus force can reduce the entrapment ratio of particles in the solidified shell, especially for smaller particles, but the effect is not obvious. The Marangoni force can play an important role in controlling the motion of particles, which increases the entrapment ratio of particles in the solidified shell obviously.

  7. Simulation of transient fluid flow in mold region during steel continuous casting

    NASA Astrophysics Data System (ADS)

    Liu, R.; Thomas, B. G.; Sengupta, J.

    2012-07-01

    A system of models has been developed to study transient flow during continuous casting and applied to simulate an event of multiple stopper-rod movements. It includes four sub-models to incorporate different aspects in this transient event. A three-dimensional (3-D) porous-flow model of the nozzle wall calculates the rate argon gas flow into the liquid steel, and the initial mean bubble size is estimated. Transient CFD models simulate multiphase flow of steel and gas bubbles in the Submerged Entry Nozzle (SEN) and mold and have been validated with experimental data from both nail dipping and Sub-meniscus Velocity Control (SVC) measurements. To obtain the transient inlet boundary conditions for the simulation, two semi-empirical models, a stopper-rod-position based model and a metal-level-based model, predict the liquid steel flow rate through the SEN based on recorded plant data. Finally the model system was applied to study the effects of stopper rod movements on SEN/mold flow patterns. Meniscus level fluctuations were calculated using a simple pressure method and compared well with plant measurements. Insights were gained from the simulation results to explain the cause of meniscus level fluctuations and the formation of sliver defects during stopper rod movements.

  8. Transient Simulation of Mold Heat Transfer and Solidification Phenomena of Continuous Casting of Steel

    NASA Astrophysics Data System (ADS)

    El-Bealy, Mostafa Omar

    2016-07-01

    A comprehensive model of heat transfer and solidification phenomena has been developed including microstructure evolution and fluctuation macrosegregation in continuously cast steel slabs with an objective of evaluation of various mold cooling conditions. The study contains plant trials, metallographic examinations, and formulation of mathematical modeling. The plant trials involved sample collection from three slab casters in use at two different steel plants. The metallographic study combined measurements of dendrite arm spacings and macrosegregation analysis of collected samples. A one-dimensional mathematical model has been developed to characterize the thermal, solidification phases, microstructure evolution, interdendritic strain, and therefore, the macrosegregation distributions. Two cooling approaches were proposed in this study to evaluate the Newtonian heat transfer coefficient in various mold regions. The first approach is a direct estimation approach (DEA), whereas the second one is a coupled approach of the interfacial resistor model and direct estimation approach (CIR/DEA). The model predictions and standard analytical models as well as the previous measurements were compared to verify and to calibrate the model where good agreements were obtained. The comparison between the model predictions and the measurements of dendrite arm spacings and fluctuated carbon concentration profiles were performed to determine the model accuracy level with different cooling approaches. Good agreements were obtained by different accuracy levels with different cooling approaches. The model predictions of thermal parameters and isotherms were analyzed and discussed.

  9. Effect of an Electromagnetic Brake on the Turbulent Melt Flow in a Continuous-Casting Mold

    NASA Astrophysics Data System (ADS)

    Miao, Xincheng; Timmel, Klaus; Lucas, Dirk; Ren, Zhongmin; Eckert, Sven; Gerbeth, Gunter

    2012-08-01

    This article presents numerical and experimental investigations with respect to the fluid flow in the continuous-casting process under the influence of an external direct current (DC) magnetic field. Numerical calculations were performed by means of the software package CFX (Ansys, Inc., Canonsburg, PA) with an implemented Reynolds-averaged Navier-Stokes (RANS)-SST turbulence model. The nonisotropic nature of the magnetohydrodynamic (MHD) turbulence was taken into account by specific modifications of the turbulence model. The numerical results were validated by flow measurements carried out in a small-scale mockup using the eutectic alloy GaInSn. The jet flow discharging from the submerged entry nozzle was exposed to a level magnetic field spanning across the entire wide side of the mold. The comparison between our numerical calculations and the experimental results displays a good agreement; in particular, we reconstructed the peculiar phenomenon of an excitation of nonsteady, nonisotropic, large-scale flow perturbations caused by the application of the DC magnetic field. Another important result of our study is the feature that the electrical boundary conditions, namely the wall conductivity ratio, have a serious influence on the mold flow while it is exposed to an external magnetic field.

  10. Mold Simulator Study of the Initial Solidification of Molten Steel in Continuous Casting Mold. Part I: Experiment Process and Measurement

    NASA Astrophysics Data System (ADS)

    Zhang, Haihui; Wang, Wanlin; Ma, Fanjun; Zhou, Lejn

    2015-10-01

    A mold simulator has been successfully used to study the initial solidification behavior of the molten low carbon steel. Coupled with 2D-IHCD calculation and PSD analysis, the variations of the responding temperatures and heat fluxes, as well as the relationship between shell surface profile, heat flux, shell thickness, mold level fluctuation, and the infiltrated slag film, were investigated in this article. The results suggested that the mold high-frequency temperatures and heat fluxes above liquid steel level vary with the oscillation of the mold, and show an opposite variation pattern as those below the shell tip. The formed shell surface profile is directly correlated to the variation of high-frequency heat fluxes, where the formation of oscillation mark is associated with a sudden increase of the heat flux during negative strip time. Mold level fluctuation contributes to the formation of the extra oscillation marks. The growth of shell thickness follows the square root law, and the instantaneous solidification factor is large near the shell tip and becomes small in the area where the deep shell surface depression is formed. The thickness of the slag film in between mold and shell is in the range of 1.4 to 2.46 mm, and the crystallization of mold flux in mold/shell gap is dynamic.

  11. Comparison of different Methods to model Transient Turbulent Magnetohydrodynamic Flow in Continuous Casting Molds

    NASA Astrophysics Data System (ADS)

    Kratzsch, C.; Asad, A.; Schwarze, R.

    2016-07-01

    Modeling of the processes in the continuous casting mold engaged many scientists once the computer-technology was able to accomplish that task. Despite that, CFD modeling of the fluid flow is still challenging. The methods allow deeper and deeper inside views into transient flow processes. Mostly two kinds of methods are applied for this purpose. URANS simulations are used for a coarse overview of the transient behavior on scales determined by the big rollers inside the mold. Besides, LES were done to study the processes on smaller scales. Unfortunately, the effort to set up a LES is orders of magnitude higher in time and space compared to URANS. Often, the flow determining processes take place in small areas inside the flow domain. Hence, scale resolving methods (SRS) came up, which resolve the turbulence in some amount in these regions, whereas they go back to URANS in the regions of less importance. It becomes more complex when dealing with magnetic fields in terms of EMBr devices. The impact of electro magnetically forces changes the flow structure remarkably. Many important effects occur, e.g. MHD turbulence, which are attributable to processes on large turbulent scales. To understand the underlying phenomena in detail, SRS allows a good inside view by resolving these processes partially. This study compares two of these methods, namely the Scale Adaptive Simulation (SAS) and the Delayed Detached Eddy Simulation (DDES), with respect to rendition of the results known from experiments and URANS simulation. The results show, that the SAS as well as the DDES are able to deliver good results with higher mesh resolutions in important regions in the flow domain

  12. Make it clear: molds, transparent casts and lightning techniques for stereomicroscopic analysis of taphonomic modifications on bone surfaces.

    PubMed

    Camarós, Edgard; Sánchez-Hernández, Carlos; Rivals, Florent

    2016-06-20

    This paper provides detailed description of a non-destructive, low-cost, and low-time consuming technique for producing high-resolution casts for the observation of taphonomic modifications on bone surfaces. The aim of the whole process is to obtain molds that accurately replicate the original bone surface at both the macro- and microscopic levels. The high quality transparent epoxy casts produced are analyzed by light microscopy and used to produce detailed microphotographs of bone surfaces. After describing each step of the process, we present some examples of its application in the case of anthropic activity, carnivores, or other post-depositional modifications. PMID:26829573

  13. BRITISH MOLDING MACHINE, PBQ AUTOMATIC COPE AND DRAG MOLDING MACHINE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    BRITISH MOLDING MACHINE, PBQ AUTOMATIC COPE AND DRAG MOLDING MACHINE MAKES BOTH MOLD HALVES INDIVIDUALLY WHICH ARE LATER ROTATED, ASSEMBLED, AND LOWERED TO POURING CONVEYORS BY ASSISTING MACHINES. - Southern Ductile Casting Company, Casting, 2217 Carolina Avenue, Bessemer, Jefferson County, AL

  14. Numerical Investigation of Shell Formation in Thin Slab Casting of Funnel-Type Mold

    NASA Astrophysics Data System (ADS)

    Vakhrushev, A.; Wu, M.; Ludwig, A.; Tang, Y.; Hackl, G.; Nitzl, G.

    2014-06-01

    The key issue for modeling thin slab casting (TSC) process is to consider the evolution of the solid shell including fully solidified strand and partially solidified dendritic mushy zone, which strongly interacts with the turbulent flow and in the meantime is subject to continuous deformation due to the funnel-type mold. Here an enthalpy-based mixture solidification model that considers turbulent flow [Prescott and Incropera, ASME HTD, 1994, vol. 280, pp. 59-69] is employed and further enhanced by including the motion of the solidifying and deforming solid shell. The motion of the solid phase is calculated with an incompressible rigid viscoplastic model on the basis of an assumed moving boundary velocity condition. In the first part, a 2D benchmark is simulated to mimic the solidification and motion of the solid shell. The importance of numerical treatment of the advection of latent heat in the deforming solid shell (mushy zone) is specially addressed, and some interesting phenomena of interaction between the turbulent flow and the growing mushy zone are presented. In the second part, an example of 3D TSC is presented to demonstrate the model suitability. Finally, techniques for the improvement of calculation accuracy and computation efficiency as well as experimental evaluations are also discussed.

  15. Large Eddy Simulation of Transient Flow and Inclusions Transport in Continuous Casting Mold under Different Electromagnetic Brakes

    NASA Astrophysics Data System (ADS)

    Liu, Zhongqiu; Li, Linmin; Li, Baokuan

    2016-06-01

    A mathematical model has been developed to analyze transient fluid flow and inclusions transport in a slab continuous casting mold, considering the effects of electromagnetic brake (EMBr) arrangement and magnetic field strength. Transient flow of molten steel in the mold is calculated by using the large eddy simulation. The electromagnetic force is incorporated into the Navier-Stokes equation. The transport of inclusion inside the mold is calculated using the Lagrangian approach based on the transient flow field. The predicted results of this model are compared with the measurements of the ultrasonic testing of the rolled steel plates and the water model experiments. The transient asymmetrical flow pattern and inclusion transport inside the mold exhibits satisfactory agreement with the corresponding measurements. With electromagnetic brake effect, the velocities around the braking region are significantly suppressed, and the recirculating flow in the lower part drops and tends to develop a plug-like flow. The EMBr arrangement has an insignificant effect on the overall removal fraction of inclusions, especially for larger inclusions. The inclusion removal rate for the flow-control mold (FCM arrangement) reduces instead compared with no EMBr, especially for smaller inclusions.

  16. A Combined Experimental and Computational Approach for the Design of Mold Topography that Leads to Desired Ingot Surface and Microstructure in Aluminum Casting.

    SciTech Connect

    Dr. Zabaras, N.; Tan, L.

    2005-07-12

    A thermomechanical study of the effects of mold topography on the solidification of Aluminum alloys at early times is provided. The various coupling mechanisms between the solid-shell and mold deformation and heat transfer at the mold/solid-shell interface during the early stages of Aluminum solidification on molds with uneven topographies are investigated. The air-gap nucleation time, the stress evolution and the solid-shell growth pattern are examined for different mold topographies to illustrate the potential control of Aluminum cast surface morphologies during the early stages of solidification using proper design of mold topographies. The unstable shell growth pattern in the early solidification stages results mainly from the unevenness of the heat flux between the solid-shell and the mold surface. This heat flux is determined by the size of the air-gaps formed between the solidifying shell and mold surface or from the value of the contact pressure. Simulation results show that a sinusoidal mold surface with a smaller wavelength leads to nucleation of air-gaps at earlier times. In addition, the unevenness in the solid-shell growth pattern decreases faster for a smaller wavelength. Such studies can be used to tune mold surfaces for the control of cast surface morphologies.

  17. A New Direct-Pour In-Mold (DPI) Technology for Producing Ductile and Compacted Graphite Iron Castings.

    SciTech Connect

    Jason Hitchings; Jay R. Hitchings

    2007-07-20

    A new "Direct Pour In-Mold" (DPI) Magnesium treatment technology has been developed that can produce both Nodular and Compacted Graphite iron. The DPI technology converts the standard horizontal runner system into a vertical one, by placing a Magnesium Ferrosilicon treatment alloy and molten metal filter into a specially designed container. The DPI container is easily placed into either vertically or horizontally parted molds, and then a base metal can be poured directly into it. The metal is treated and filtered as it passes through, and then proceeds directly into a runner or casting cavity. Various sizes of containers provide all of the necessary components required to deliver a range of weights of treated and filtered metal at accurate and consistent flow rates. The DPI containers provide energy savings over competing techniques, increased mold yields, very high Magnesium recovery, zero Magnesium fume, and no post inoculation is required. By treating the metal just prior to it entering a casting cavity many other benefits and advantages are also realized.

  18. Hybrid optics for the visible produced by bulk casting of sol-gel glass using diamond-turned molds

    SciTech Connect

    Bernacki, B.E.; Miller, A.C.; Maxey, L.C.; Cunningham, J.P.; Moreshead, W.V.; Nogues, J.L.R.

    1995-07-01

    Recent combinations of diffractive and refractive functions in the same optical component allow designers additional opportunities to make systems more compact and enhance performance. This paper describes a research program for fabricating hybrid refractive/diffractive components from diamond-turned molds using the bulk casting of sol-gel silica glass. The authors use the complementary dispersive nature of refractive and diffractive optics to render two-color correction in a single hybrid optical element. Since diamond turning has matured as a deterministic manufacturing technology, techniques previously suitable only in the infrared are now being applied to components used at visible wavelengths. Thus, the marriage of diamond turning and sol-gel processes offers a cost-effective method for producing highly customized and specialized optical components in high quality silica glass. With the sol-gel casting method of replication, diamond-turned mold costs can be shared over many pieces. Diamond turning takes advantage of all of the available degrees of freedom in a single hybrid optical element: aspheric surface to eliminate spherical aberration, kinoform surface for control of primary chromatic aberration, and the flexibility to place the kinoform on non-planar surfaces for maximum design flexibility. The authors discuss the critical issues involved in designing the hybrid element, single point diamond-turning the mold, and fabrication in glass using the sol-gel process.

  19. Method for molding ceramic powders using a water-based gel casting process

    DOEpatents

    Jenny, Mark A.; Omalete, Ogbemi O.

    1992-09-08

    A method for molding ceramic powders comprises forming a slurry mixture including ceramic powder, a dispersant, and a monomer solution. The monomer solution includes at least one monofunctional monomer and at least one difunctional monomer, a free-radical initiator, and a aqueous solvent. The slurry mixture is transferred to a mold, and the mold containing the slurry mixture is heated to polymerize and crosslink the monomer and form a firm polymer-solvent gel matrix. The solid product may be removed from the mold and heated to first remove the solvent and subsequently remove the polymer, whereafter the product may be sintered.

  20. Method for molding ceramic powders using a water-based gel casting

    DOEpatents

    Janney, Mark A.; Omatete, Ogbemi O.

    1991-07-02

    A method for molding ceramic powders comprises forming a slurry mixture including ceramic powder, a dispersant, and a monomer solution. The monomer solution includes at least one monofunctional monomer and at least one difunctional monomer, a free-radical initiator, and a aqueous solvent. The slurry mixture is transferred to a mold, and the mold containing the slurry mixture is heated to polymerize and crosslink the monomer and form a firm polymer-solvent gel matrix. The solid product any be removed from the mold and heated to first remove the solvent and subsequently remove the polymer, whereafter the product may be sintered.

  1. Heat transfer at the mold-metal interface in permanent mold casting of aluminum alloys project. Annual project status report for the period October 1, 1997 to September 30, 1998

    SciTech Connect

    Pehlke, R.D.; Hao, S.W.

    1998-09-30

    In the first year of this three-year project, substantial progress has been achieved. This project on heat transfer coefficients in metal permanent mold casting is being conducted in three areas. They are the theoretical study at the University of Michigan, the experimental investigations of squeeze casting and semi-solid casting at CMI-Tech Center, and the experimental investigation of low pressure permanent mold casting at Amcast Automotive. U-M did an initial geometry which was defined for ProCAST to solve, and then a geometry half the size was defined and solved using the same boundary conditions. A conceptual mold geometry was examined and is represented as an axisymmetric element.Furthermore, the influences of the localized heat transfer coefficients on the casting process were carefully studied. The HTC Evaluator has been proposed and initially developed by the U-M team. The Reference and the Database Modules of the HTC Evaluator have been developed, and extensively tested. A series of technical barriers have been cited and potential solutions have been surveyed. At the CMI-Tech Center, the Kistler direct cavity pressure measurement system has been purchased and tested. The calibrations has been evaluated. The probe is capable of sensing a light finger pressure. The experimental mold has been designed and modified. The experimental mold has been designed and modified. The first experiment is scheduled for October 14, 1998. The geometry of the experimental hockey-puck casting has been given to the U-M team for numerical analysis.

  2. Effect of Al2O3 on the Crystallization of Mold Flux for Casting High Al Steel

    NASA Astrophysics Data System (ADS)

    Zhou, Lejun; Wang, Wanlin; Zhou, Kechao

    2015-06-01

    In order to lower the weight of automotive bodies for better fuel-efficiency and occupant safety, the demand for high Al-containing advanced high strength steel, such as transformation-induced plasticity and twinning-induced plasticity steel, is increasing. However, high aluminum content in steels would tend to significantly affect the properties of mold flux during the continuous casting process. In this paper, a kinetic study of the effect of Al2O3 content on the crystallization behavior of mold flux was conducted by using the single hot thermocouple technique and the Johnson-Mehl-Avrami model combined with the Arrhenius Equation. The results suggested that Al2O3 behaves as an amphoteric oxide in the crystallization process of mold flux. The precipitated phases of mold flux change from cuspidine (Ca4Si2O7F2) into nepheline (NaAlSiO4) and CaF2, and then into gehlenite (Ca2Al2SiO7) with the increase of Al2O3 content. The kinetics study of the isothermal crystallization process indicated that the effective crystallization rate ( k) and Avrami exponent ( n) also first increased and then decreased with the increase of Al2O3 content. The values for the crystallization activation energy of mold flux with different Al2O3 contents were E R0.8A7 = 150.76 ± 17.89 kJ/mol, E R0.8A20 = 136.43 ± 6.48 kJ/mol, E R0.8A30 = 108.63 ± 12.25 kJ/mol and E R0.8A40 = 116.15 ± 8.17 kJ/mol.

  3. Rapid tooling for functional prototyping of metal mold processes: Literature review on cast tooling

    SciTech Connect

    Baldwin, M.D.; Hochanadel, P.W.

    1995-11-01

    This report is a literature review on cast tooling with the general focus on AISI H13 tool steel. The review includes processing of both wrought and cast H13 steel along with the accompanying microstructures. Also included is the incorporation of new rapid prototyping technologies, such as Stereolithography and Selective Laser Sintering, into the investment casting of tool steel. The limiting property of using wrought or cast tool steel for die casting is heat checking. Heat checking is addressed in terms of testing procedures, theories regarding the mechanism, and microstructural aspects related to the cracking.

  4. [Flow of molten metal in denture base in horizontal centrifugal casting procedure. (Part 2) Flow, inflow volume and casting time of molten metal passing through several sprues into model denture plate mold (author's transl)].

    PubMed

    Okamura, H

    1978-10-01

    Two types of spruing methods were used in the casting of the denture type model pattern (thickness, 0.43 mm). Flow of molten metal in the mold was filmed by the improved system of Part 1. When three sprues were attached to the pattern vertically, molten metal passed through each sprue gate flowed being affected by the direction of gravity and revolution of casting machine, and gathered at the lower part of the mold. Next molten metal filled the mold from the lower part to the upper part. In this spruing type, molten metal turned its direction of flow several times. At the middle stage of casting, the inflow volume per unit time (inflow rate), v (mm3/10-2)s)was evaluated as v = 12.36 + 5.16A-0.16 A2 (A: total cross-sectional areas of sprues). The inflow rate increased with increase of the area of the sprues, but it saturated. When the main sprue and the subsprues were attached at the posterior border, the molten metal filled the mold from the lower part to the upper part quietly. In this spruing type, the casting mold was set facing its sprue gates downwards. The inflow rate at the middle stage of casting was evaluated as v = 21.05 + 1.79 C (C: the cross-sectional area of the main sprue). The inflow rate increased linearly with increase of the area of the main sprue. PMID:392022

  5. [Effects of mold preheating temperatures and the time of melt casting on the structure of cast denture frameworks].

    PubMed

    Biffar, R; Balz, U

    1989-11-01

    At casting temperatures of 1330 degrees to 1530 degrees C and preheating temperatures of 900 degrees to 1100 degrees C, 28 cast denture frameworks were manufactured using the cobalt chromium alloy Biosil f (Degussa). The inner defects were detected by X-ray defectoscopy and the grain numbers of clasp, connector and basis elements determined by metallography. The best results for compact castings were observed at a temperature range of 1410 degrees to 1480 degrees C. Casting previous to the melting of the last alloy cube results in a structure of clasps and connectors with 100-200 grains/mm2 and a high amount of defects; exceeding the liquidus temperature of 1380 degrees C produces grain numbers of 20-30/mm2, while a casting temperature of 1530 degrees C results in 3-5/mm2. Overheating of the melt, also in connection with low preheating temperatures, is probably a cause for the premature loss of clasp retention and fracture of many denture frameworks. PMID:2700705

  6. Mechanical Strength and Failure Characteristics of Cast Mg-9 pctAl-1 pctZn Alloys Produced by a Heated-Mold Continuous Casting Process: Tensile Properties

    NASA Astrophysics Data System (ADS)

    Okayasu, Mitsuhiro; Takeuchi, Shuhei; Ohfuji, Hiroaki

    2014-11-01

    The mechanical properties and failure characteristics of a cast Mg alloy (AZ91: Mg-Al8.9-Zn0.6-Mn0.2) produced by a heated-mold continuous casting process (HMC) are investigated. In a modification of the original HMC process, the cooling of the liquid alloy by direct water spray is carried out in an atmosphere of high-purity argon gas. The HMC-AZ91 alloy exhibits excellent mechanical properties (high strength and high ductility) that are about twice as high as those for the same alloy produced by conventional gravity casting. The increased material strength and ductility of the HMC sample are attributed to nanoscale and microscale microstructural characteristics. The fine grains and tiny spherical eutectic structures ( e.g., Mg17Al12 and Al6Mn) distributed randomly in the matrix of the HMC alloy result in resistance to dislocation movement, leading to high tensile strength. Basal slip on (0001) planes in the relatively organized crystal orientation of the HMC alloy, as well as grain boundary sliding through tiny spherical eutectic structures, results in high ductility. Details of the failure mechanism under static loading in the HMC alloy are also discussed using failure models.

  7. Influences of Basicity and Li2O on the Properties of Fluorine-Free Mold Flux for the Casting of Medium Carbon Steels

    NASA Astrophysics Data System (ADS)

    Wang, Wanlin; Yan, Xiong; Zhou, Lejun; Xie, Senlin; Huang, Daoyuan

    2016-04-01

    An investigation was carried out to study the influences of basicity and Li2O on the melting, crystallization, and heat transfer behavior of Fluorine-free mold flux designed for the casting of medium carbon steels using double hot thermocouple technology and infrared emitter technique. The results showed that with the addition of basicity, the melting and crystallization temperatures of the mold fluxes were increased, and the final heat transfer rate was reduced, as the basicity tends to promote the crystallization behavior of the designed mold fluxes. Besides, with the increase of Li2O content in the mold flux, the melting and crystallization temperature decreased, as the Li2O tends to inhibit the formation of high melting temperature crystal and lower the system melting temperature zone; meanwhile the crystallization capability of the mold flux was enhanced in the low-temperature region. Moreover, the results of EDS and XRD were confirmed that the main crystal phase in the Fluorine-free mold fluxes is calcium borate silicate (Ca11Si4B2O22). Those results obtained can provide guidelines for the design of new Fluorine-free mold flux for the casting medium carbon steels.

  8. Spray-formed tooling for injection molding and die casting applications

    SciTech Connect

    K. M. McHugh; B. R. Wickham

    2000-06-26

    Rapid Solidification Process (RSP) Tooling{trademark} is a spray forming technology tailored for producing molds and dies. The approach combines rapid solidification processing and net-shape materials processing in a single step. The ability of the sprayed deposit to capture features of the tool pattern eliminates costly machining operations in conventional mold making and reduces turnaround time. Moreover, rapid solidification suppresses carbide precipitation and growth, allowing many ferritic tool steels to be artificially aged, an alternative to conventional heat treatment that offers unique benefits. Material properties and microstructure transformation during heat treatment of spray-formed H13 tool steel are described.

  9. Spray-formed Tooling for Injection Molding and Die Casting Applications

    SciTech Connect

    Mc Hugh, Kevin Matthew

    2000-06-01

    Rapid Solidification Process (RSP) ToolingTM is a spray forming technology tailored for producing molds and dies. The approach combines rapid solidification processing and net-shape materials processing in a single step. The ability of the sprayed deposit to capture features of the tool pattern eliminates costly machining operations in conventional mold making and reduces turnaround time. Moreover, rapid solidification suppresses carbide precipitation and growth, allowing many ferritic tool steels to be artificially aged, an alternative to conventional heat treatment that offers unique benefits. Material properties and microstructure transformation during heat treatment of spray-formed H13 tool steel are described.

  10. FILLING MOLDS MADE ON THE BRITISH MOLDING MACHINE, AUTOMATIC COPE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    FILLING MOLDS MADE ON THE BRITISH MOLDING MACHINE, AUTOMATIC COPE AND DRAG (BMM) FROM MOBILE LADLE. EMPTY BULL LADLE IN FOREGROUND. - Southern Ductile Casting Company, Casting, 2217 Carolina Avenue, Bessemer, Jefferson County, AL

  11. Thermal calculation of a mold for continuous casting of metal strip

    NASA Astrophysics Data System (ADS)

    Abramenko, A. N.; Kalinichenko, A. S.; Krivosheev, Yu. K.

    1991-07-01

    The article describes the design of a roll mold consisting of a block of centrifugal heat pipes, a radial and an axial one. It presents the method of calculating the structural elements, the capillary structure, and the temperature gradient of the system, proceeding from the conditions of ensuring normal processes of heat and mass transfer in the zones of transport and of phase transition.

  12. Investigation on the Effect of Mold Constraints and Cooling Rate on Residual Stress During the Sand-Casting Process of 1086 Steel by Employing a Thermomechanical Model

    NASA Astrophysics Data System (ADS)

    Baghani, Amir; Davami, Parviz; Varahram, Naser; Shabani, Mohsen Ostad

    2014-06-01

    In this study, the effects of mold constraints and cooling rate on residual stress were analyzed during the shaped casting process. For this purpose, an H-shaped sample was designed in which the contraction of its middle portion is highly restricted by the mold during the cooling process. The effects of an increasing cooling rate combined with mold constraints were analyzed by reducing the thickness of the middle portion in the second sample. A three-dimensional coupled temperature-displacement analysis was performed in finite-element code ABAQUS to simulate residual stress distribution, and then numerical results were verified by the hole-drilling strain-gauge method. It was concluded that the mold constraints have a greater effect on the values of residual stress than the cooling rate (thin section) in steel sand casting. Increasing the cooling rate would increase the amount of residual stress, only in the presence of mold constraints. It is also suggested that employing the elastic-plastic stress model for the sand mold will satisfy the experimental results and avoid exaggerated values of residual stress in simulation.

  13. Soft magnetic properties of bulk FeCoMoPCBSi glassy core prepared by copper mold casting

    NASA Astrophysics Data System (ADS)

    Zhang, Mingxiao; Kong, Fanli; Wang, Anding; Chang, Chuntao; Shen, Baolong

    2012-04-01

    Bulk Fe66Co10Mo3.5P10C4B4Si2.5 glassy core of 10 mm in outer diameter, 6 mm in inner diameter, and 1 mm in thickness was successfully prepared by copper mold casting. The effects of annealing treatments on magnetic properties and microstructure of these cores were investigated. After an optimum annealing treatment, the resulting bulk glassy core exhibits good magnetic properties, i.e., high saturation magnetic flux density of 1.23 T, low coercive force of 1.0 A/m, high maximum permeability of 450 000, respectively. In addition, the glassy core also shows low core loss of 0.4 W/kg at 50 Hz and at maximum magnetic flux density of 1 T. The synthesis of bulk glassy core with excellent magnetic properties is encouraging for enlarging the application field of ferromagnetic bulk glassy alloys.

  14. Microstructure and mechanical properties of BFe10 cupronickel alloy tubes fabricated by a horizontal continuous casting with heating-cooling combined mold technology

    NASA Astrophysics Data System (ADS)

    Mei, Jun; Liu, Xin-hua; Xie, Jian-xin

    2012-04-01

    A new horizontal continuous casting method with heating-cooling combined mold (HCCM) technology was explored for fabricating high-quality thin-wall cupronickel alloy tubes used for heat exchange pipes. The microstructure and mechanical properties of BFe10 cupronickel alloy tubes fabricated by HCCM and traditional continuous casting (cooling mold casting) were comparatively investigated. The results show that the tube fabricated by HCCM has smooth internal and external surfaces without any defects, and its internal and external surface roughnesses are 0.64 μm and 0.85 μm, respectively. The tube could be used for subsequent cold processing without other treatments such as surface planning, milling and acid-washing. This indicates that HCCM can effectively reduce the process flow and improve the production efficiency of a BFe10 cupronickel alloy tube. The tube has columnar grains along its axial direction with a major casting texture of left\\{ {012} right\\}left< {6bar 21} rightrangle. Compared with cooling mold casting ( δ = 36.5%), HCCM can improve elongation ( δ = 46.3%) by 10% with a slight loss of strength, which indicates that HCCM remarkably improves the cold extension performance of a BFe10 cupronickel alloy tube.

  15. Four-phase fully-coupled mold-filling and solidification simulation for gas porosity prediction in aluminum sand casting

    NASA Astrophysics Data System (ADS)

    Jakumeit, J.; Jana, S.; Waclawczyk, T.; Mehdizadeh, A.; Sadiki, A.; Jouani, J.

    2012-07-01

    The impact of mold-filling and oxide film enclosure on gas porosity in A356 was investigated using a three-phase, fully-coupled, mold-filling and solidification simulation. For the prediction of gas porosity, a fourth hydrogen phase was added. At the solidification front hydrogen is rejected from the solid and accumulates in the melt. Pores nucleate if the solute gas exceeds the solubility limit. Air and melt are separated by a volume of fluid interface and special treatment of the hydrogen phase convection was necessary to limit the hydrogen to the melt. Folding of the melt surface was used as a source for oxide film entrainment. These oxide films were transported with the melt and used as nucleation sites for gas porosity formation. The influence of melt flow due to filling and oxide film distribution was analyzed using a simple 3-block test geometry. The test geometry was cast in A356 and analyzed by computer tomography to validate the porosity prediction.

  16. Thermal calculation of a mold for continuous casting of metal strip

    SciTech Connect

    Abramenko, A.N.; Kalinichenko, A.S.; Krivosheev, Y.K.

    1992-01-01

    The article describes the design of a roll mold consisting of a block of centrifugal heat pipes, a radial and an axial one. It presents the method of calculating the structural elements, the capillary structure, and the temperature gradient of the system, proceeding from the conditions of ensuring normal processes of heat and mass transfer in the zones of transport and of phase transition. 8 refs., 2 figs.

  17. The Development of CaO-SiO2-B2O3-based Fluorine-Free Mold Flux for a Continuous Casting Process

    NASA Astrophysics Data System (ADS)

    Zhou, Lejun; Wang, Wanlin

    2016-05-01

    Designing and developing high-performance fluorine-free (F-free) mold flux has become a hot topic in steel continuous casting processes, with concerns of environment protection and energy saving. In conventional commercial mold flux, fluorine plays important roles on the properties as it works as a fluxing agent; however, it tends to cause serious environmental and health problems. In this paper, a new F-free mold flux based on the CaO-SiO2-B2O3 slag system has been introduced through summarizing previous works. The melting temperature range of F-free mold flux decreases with the addition of Na2O/Li2O and B2O3; the viscosity and heat flux decrease with the increase of basicity and Na2O/Li2O, as well as the decrease of B2O3 contents. Also, the crystallization temperatures of F-free mold fluxes increase with the increase of basicity and Na2O/Li2O content. The analyses of EDS and XRD show that Ca11Si4B2O22 and Ca14Mg2(SiO4)8 are the two main precipitated crystalline phases in F-free mold fluxes, and that the Ca11Si4B2O22 is a common and stable crystalline phase in the designed F-free mold fluxes system that shows the potential to replace Ca4Si2O7F2 in conventional flourine-containing mold fluxes.

  18. Thin Wall Iron Castings

    SciTech Connect

    J.F. Cuttino; D.M. Stefanescu; T.S. Piwonka

    2001-10-31

    Results of an investigation made to develop methods of making iron castings having wall thicknesses as small as 2.5 mm in green sand molds are presented. It was found that thin wall ductile and compacted graphite iron castings can be made and have properties consistent with heavier castings. Green sand molding variables that affect casting dimensions were also identified.

  19. Transient Two-Phase Flow in Slide-Gate Nozzle and Mold of Continuous Steel Slab Casting with and without Double-Ruler Electro-Magnetic Braking

    NASA Astrophysics Data System (ADS)

    Cho, Seong-Mook; Thomas, Brian G.; Kim, Seon-Hyo

    2016-07-01

    Transient mold flow could produce undesirable surface instabilities and slag entrainments, leading to the formation of defects during continuous slab casting of steel. In this work, two Large Eddy Simulations coupled with Discrete Phase Model are run, with and without MagnetoHydroDynamic model, to gain new insights into the surface variations of molten steel-argon gas flow with anisotropic turbulence in the slide-gate nozzle and the mold, with and without double-ruler Electro-Magnetic Braking (EMBr). The model calculations are validated with plant measurements, and applied to investigate the flow variations related to the slide gate on nozzle swirl, jet wobbling, and surface flow variations by quantifying the variations of velocity, horizontal angle, and vertical angle of the transient flow. Transient flow in the slide-gate nozzle bottom is almost always swirling, alternating chaotically between clockwise and counter-clockwise rotation. The clockwise swirl, caused by stronger flow down the same side of the nozzle as the open area near the Outside Radius side of the slide-gate middle plate, produces faster jet flow and higher velocity flow across the top surface of the mold. Counter-clockwise swirl produces slower jet and surface flow, but with more variations. The double-ruler EMBr decreases the asymmetry and duration of velocity variations during nozzle swirl flipping, resulting in less flow variations in the jet and across the surface in the mold.

  20. TENDING THE MOLD, DURING THE TRANSFER FROM TUNDISH TO MOLD ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    TENDING THE MOLD, DURING THE TRANSFER FROM TUNDISH TO MOLD TO CONTAINMENT CHAMBER IS CONTINUOUS CASTING OPERATOR, CALVIN ANDERS. - U.S. Steel, Fairfield Works, Continuous Caster, Fairfield, Jefferson County, AL

  1. Pressure molding of powdered materials improved by rubber mold insert

    NASA Technical Reports Server (NTRS)

    1964-01-01

    Pressure molding tungsten microspheres is accomplished by applying hydraulic pressure to a silicone rubber mold insert with several barrel shaped chambers which is placed in a steel die cavity. This technique eliminates castings containing shear fractures.

  2. The Structure and Properties of Inductively Coupled Plasma Assisted Magnetron Sputtered Nanocrystalline NbN Coatings in Corrosion Protective Die Casting Molds.

    PubMed

    Chun, Sung-Yong

    2016-02-01

    Niobium nitride coatings for the surface modified die casting molds with various ICP powers have been prepared using ICP assisted magnetron sputtering. The applied ICP power was varied from 0 to 200 W. The deposited coatings were characterized post-deposition using X-ray diffractometry (XRD) and atomic force microscopy (AFM). Single NbN phased coatings with nano-grain sized (<7.6 nm) were identified. The corrosion resistance and hardness of each coating were evaluated from potentiostat and nanoindentator. Superior corrosion protective coatings in excess of 13.9 GPa were deposited with assistance of ICP plasma during sputtering. PMID:27433719

  3. A comparison between the dimensions of positive transtibial residual limb molds prepared by air pressure casting and weight-bearing casting methods

    PubMed Central

    Hajiaghaei, Behnam; Ebrahimi, Ismail; Kamyab, Mojtaba; Saeedi, Hassan; Jalali, Maryam

    2016-01-01

    Background: Creating a socket with proper fit is an important factor to ensure the comfort and control of prosthetic devices. Several techniques are commonly used to cast transtibial stumps but their effect on stump shape deformation is not well understood. This study compares the dimensions, circumferences and volumes of the positive casts and also the socket comfort between two casting methods. Our hypothesis was that the casts prepared by air pressure method have less volume and are more comfortable than those prepared by weight bearing method. Methods: Fifteen transtibial unilateral amputees participated in the study. Two weight bearing and air pressure casting methods were utilized for their residual limbs. The diameters and circumferences of various areas of the residual limbs and positive casts were compared. The volumes of two types of casts were measured by a volumeter and compared. Visual Analogue Scale (VAS) was used to measure the sockets fit comfort. Results: Circumferences at 10 and 15 cm below the patella on the casts were significantly smaller in air pressure casting method compared to the weight bearing method (p=0.00 and 0.01 respectively). The volume of the cast in air pressure method was lower than that of the weight bearing method (p=0.006). The amputees found the fit of the sockets prepared by air pressure method more comfortable than the weight bearing sockets (p=0.015). Conclusion: The air pressure casting reduced the circumferences of the distal portion of residual limbs which has more soft tissue and because of its snug fit it provided more comfort for amputees, according to the VAS measurements. PMID:27390711

  4. Relationship between casting distortion, mold filling, and interfacial heat transfer. Annual technical report, September 1997 - September 1998

    SciTech Connect

    Woodbury, K.A.; Parker, J.K.; Piwonka, T.S.; Owusu, Y.

    1998-10-22

    In the third year of this program, the final castings necessary to evaluate the effect of casting orientation and gating in silica sand lost foam were poured and measured using a CMM machine. Interfacial heat transfer and gap formation measurements continued. However, significant problems were encountered in making accurate measurements. No consistent evidence of gap formation was found in aluminum sand casting. Initial analysis yields heat transfer values below those previously reported in the literature. The program in continuing.

  5. Comparative sampling molds evaluation

    SciTech Connect

    Pierrard, L.; Jarry, P.; Charbonnier, J.; Rigaut, C.

    1996-10-01

    The metallurgical industry needs to cast alloys with narrow tolerances in their chemical composition in order to reduce variability of their use properties. Therefore appropriate sampling practices and analytical methods are required. Both accuracy and precision of the analytical results are limited by the non-homogeneity of as-cast disk or cylinder samples, which results from macrosegregation phenomenon. This paper presents a comparison between six commonly used molds: four molds recommended by ASTM standards (center-pour molds type B and vacuum mold), mushroom shaped and cylinder molds. Two complementary approaches are exhibited for the different molds designs: (1) solidification modeling in order to predict macrosegregation localization using the Simulor software; (2) experimental characterization. Radial and axial segregation profiles are determined by Analytical Scanning Electron Microscopy in addition to analytical precision evaluation by spark optical emission and X-Ray fluorescence spectrometries for a given machining depth.

  6. Evaluation of Interfacial Interactions Between Ti-6Al-4V and Mold Use Ti-Added Backup Coat in Investment Casting

    NASA Astrophysics Data System (ADS)

    Cheng, Xu; Chai, Lianjing; Wu, Guoqing; Wang, Hong; Nan, Hai

    2016-05-01

    In this article, the chemical inertness of shell using Ti-added mullite backup coat against molten Ti-6Al-4V (Ti64) alloy was investigated. The metal/shell interfacial microstructures and compositions were characterized using an optical microscope, scanning electron microscope, roughness tester, and X-ray diffractometer; the hardened layer thickness was evaluated using a microhardness tester. By adding titanium powder into the mullite backup coat, the alpha case and hardened layer thickness of the Ti64 castings were largely reduced with good surface finishing. Silicon ions, from the backup coat, penetrated into the alloy and coarsened the β lath at the metal/shell interfacial area. The Ti powder in the mullite backup coat oxidized and interacted with silica during mold firing and casting, which reduced the silicon and oxygen concentrations at the metal/shell interfacial area. The oxygen penetration depth is thicker than the alpha case layer thickness, and around 0.26 wt pct, oxygen can obviously coarsen the alpha lath at the metal/shell interfacial area during investment casting.

  7. Mold Allergy

    MedlinePlus

    ... navigation Home ▸ Conditions & Treatments ▸ Allergies ▸ Mold Allergy Share | Mold Allergy Overview Symptoms & Diagnosis Treatment & Management Mold Allergy Overview Molds are tiny fungi whose spores ...

  8. REFRACTORY COATING FOR GRAPHITE MOLDS

    DOEpatents

    Stoddard, S.D.

    1958-06-24

    Refractory coating for graphite molds used in the casting of uranium is described. The coating is an alumino-silicate refractory composition which may be used as a mold surface in solid form or as a coating applied to the graphite mold. The composition consists of a mixture of ball clay, kaolin, alumina cement, alumina, water, sodium silicate, and sodium carbonate.

  9. Effect of the Solution Annealing and Chemical Passivation Followed by Aging on the Corrosion of Shell Mold Cast CF8 Stainless Steel

    NASA Astrophysics Data System (ADS)

    Kim, Kuk-Jin; Ju, Heongkyu; Moon, Young-Dae; Hong, Jun Ho; Pak, Sung Joon

    2016-07-01

    The effects of solution annealing and passivation of shell mold cast CF8 stainless steels on Elbow pipe fittings with 2-month room temperature aging have been studied using a corrosion technique. The resistance of corrosion increased with 2-month room temperature aging combined with solid solution annealing and chemical passivation. The mode of corrosion was deeply related to the δ-ferrite content, permeability, and passivation. The corrosion probability decreased as both the δ-ferrite content and the permeability decreased. Therefore, it is considered that δ-ferrite content and passive film of Cr2O3 play an important role in corrosion resistance of CF8 Elbow pipe fittings due to the long-term aging with solid solution annealing and chemical passivation. This result shows that the corrosion resistance of CF8 fittings can be enhanced by the solid solution annealing and chemical passivation. Decreased ferrite phases and permeability improve IGC resistance in CF8 steel.

  10. Casting materials

    DOEpatents

    Chaudhry, Anil R.; Dzugan, Robert; Harrington, Richard M.; Neece, Faurice D.; Singh, Nipendra P.

    2011-06-14

    A foam material comprises a liquid polymer and a liquid isocyanate which is mixed to make a solution that is poured, injected or otherwise deposited into a corresponding mold. A reaction from the mixture of the liquid polymer and liquid isocyanate inside the mold forms a thermally collapsible foam structure having a shape that corresponds to the inside surface configuration of the mold and a skin that is continuous and unbroken. Once the reaction is complete, the foam pattern is removed from the mold and may be used as a pattern in any number of conventional casting processes.

  11. Heat transfer at the mold-metal interface in permanent mold casting of aluminum alloys project. Quarterly project status report, October 1--December 31, 1998

    SciTech Connect

    Pehlke, R.D.; Hao, S.W.

    1998-12-31

    The first series of experiments at the CMI-Tech Center was successfully conducted on October 14 and 15 with the participation of the University of Michigan team. The preliminary experimental results indicate that the die surface temperatures (or near the surface) have a close correlation with the metal pressure profiles. Considering the difference in timing of the peak die temperatures, the high melt temperature and hotter die temperature for Inter 54 might cause a longer solidification time, and the pressure would decrease more slowly than for Inter 12. The slopes of the metal pressure profiles at the low pressure setting are almost linear. This may mean that the low metal pressure couldn`t effectively keep a pressure channel opened. In other words, as temperature decreased, the solid fraction increased and the solidified shell strengthened, and the pressure, which couldn`t overcome the resistance, would drop linearly. However, at the high pressure, there are inflection points in the pressure profiles. The inflection points are at about 8,500 psi for both the low and the high melt temperature settings. This suggests that the metal pressure was sufficient enough to overcome the resistance of the solidified shell before the inflection point was reached. A preliminary microstructure analysis shows that the dendrite arms at the location near the gate are much coarser than that at the top of the casting. The influence of intensification pressure on microstructure needs further verification and study.

  12. Surface 3D Micro Free Forms: Multifunctional Microstructured Mesoporous α-Alumina by in Situ Slip Casting Using Excimer Laser Ablated Polycarbonate Molds.

    PubMed

    Rowthu, Sriharitha; Böhlen, Karl; Bowen, Paul; Hoffmann, Patrik

    2015-11-11

    Ceramic surface microstructuring is a rapidly growing field with a variety of applications in tribology, wetting, biology, and so on. However, there are limitations to large-area microstructuring and fabrication of three-dimensional (3D) micro free forms. Here, we present a route to obtain intricate surface structures through in situ slip casting using polydimethylsiloxane (PDMS) negative molds which are replicated from excimer laser ablated polycarbonate (PC) master molds. PC sheets are ablated with a nanosecond KrF (λ = 248 nm) excimer laser mask projection system to obtain micron-scale 3D surface features over a large area of up to 3 m(2). Complex surface structures that include 3D free forms such as 3D topography of Switzerland, shallow structures such as diffractive optical elements (60 nm step) and conical micropillars have been obtained. The samples are defect-free produced with thicknesses of up to 10 mm and 120 mm diameter. The drying process of the slip cast alumina slurry takes place as a one-dimensional process, through surface evaporation and water permeation through the PDMS membrane. This allows homogeneous one-dimensional shrinkage during the drying process, independent of the sample's lateral dimensions. A linear mass diffusion model has been proposed to predict and explain the drying process of these ceramic colloidal suspensions. The calculated drying time is linearly proportional to the height of the slurry and the thickness of the negatively structured PDMS and is validated by the experimental results. An experimentally observed optimum Sylgard PDMS thickness range of ∼400 μm to 1 mm has achieved the best quality microstructured green compacts. Further, the model predicts that the drying time is independent of the microstructured areas and was validated using experimental observations carried out with microstructured areas of 300 mm(2), 1200 mm(2), and 120 cm(2). Therefore, in principle, the structures can be further replicated in areas up

  13. HUNTER 20 MATCHPLATE MOLDING MACHINE 'SQUEEZING' BOTH HALVES OF A ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    HUNTER 20 MATCHPLATE MOLDING MACHINE 'SQUEEZING' BOTH HALVES OF A MOLD SURROUNDING A MATCHPLATE PATTERN, DENNIS GRAY OPERATOR. - Southern Ductile Casting Company, Casting, 2217 Carolina Avenue, Bessemer, Jefferson County, AL

  14. High coercivity microcrystalline Nd-rich Nd-Fe-Co-Al-B bulk magnets prepared by direct copper mold casting

    NASA Astrophysics Data System (ADS)

    Zhao, L. Z.; Hong, Y.; Fang, X. G.; Qiu, Z. G.; Zhong, X. C.; Gao, X. S.; Liu, Z. W.

    2016-06-01

    High coercivity Nd25Fe40Co20Al15-xBx (x=7-15) hard magnets were prepared by a simple process of injection casting. Different from many previous investigations on nanocomposite compositions, the magnets in this work contain hard magnetic Nd2(FeCoAl)14B, Nd-rich, and Nd1+ε(FeCo)4B4 phases. The magnetic properties, phase evolution, and microstructure of the as-cast and annealed magnets were investigated. As the boron content increased from 7 to 11 at%, the intrinsic coercivity Hcj of the as-cast magnet increased from 816 to 1140 kA/m. The magnets annealed at 750 °C have shown more regular and smaller grains than the as-cast alloys, especially for the x=11 alloy. The high intrinsic coercivities for the annealed alloys with x=8~11 result from the presence of small-sized grains in the microstructure. The highest Hcj of 1427 kA/m was obtained for the heat treated alloy with x=10. This work provides an alternative approach for preparing fully dense Nd-rich bulk hard magnets with relatively good properties.

  15. Plastic molds reduce cost of encapsulating electric cable connectors

    NASA Technical Reports Server (NTRS)

    Knott, D.

    1964-01-01

    Resin casting of the aluminum master pattern forms a plastic mold for encapsulating a cable connector. An elastomer is injected into the mold and cured. The mold is disassembled leaving an elastomeric encapsulation around the connector.

  16. Diamond turned master molds for bulk casting of sol-gel silica diffractive optical elements. Final report

    SciTech Connect

    Maxey, L.C.; Nogues, J.L.; Moreshead, B.

    1997-08-01

    This CRADA has combined the resources of a national laboratory and an innovative small company to investigate the production of diffractive lenses in silica glass, using diamond turned master molds. The method for producing these lenses combines the unique characteristics of the sol-gel silica replication process, pioneered by Geltech, with the state-of-the-art diamond turning expertise of the Oak Ridge Centers for Manufacturing Technology (ORCMT). A conventional lens focuses light by using a curved surface to refract (or bend) the incoming light so that it will form an image. These lenses are usually thick glass elements with one or both surfaces shaped into convex or concave spherical shapes. Traditionally, these lenses are produced by grinding and polishing the glass to the desired shape. Light can also be focused using the phenomenon of diffraction, rather than refraction. A lens of this type uses precision microscopic surface features to bend the light so that it forms an image. The result is a lens that is thinner and lighter than its refractive counterpart. Production of diffractive lenses requires the ability to accurately produce the precision microscopic features necessary to achieve controlled diffraction. Diffractive lenses have, for the most part, been limited to infra-red applications because the manufacturing technologies available have not enabled their use at visible wavelengths. Except in limited applications, these lenses have remained laboratory curiosities, because they must be individually produced by diamond turning infra-red optical materials. Geltech`s sol-gel silica replication process offers the opportunity to mass produce diffractive lenses in high quality silica glass. These lenses can be produced by diamond turning the necessary precision microscopic surface features into master surfaces that are replicated into intermediate molds. These molds are then used to produce a batch of diffractive lenses using the sol-gel process.

  17. CASTING APPARATUS

    DOEpatents

    Gray, C.F.; Thompson, R.H.

    1958-09-23

    An apparatus is described for casting small quantities of uranlum. It consists of a crucible having a hole in the bottom with a mold positioned below. A vertical rcd passes through the hole in the crucible and has at its upper end a piercing head adapted to break the oxide skin encasing a molten uranium body. An air tight cylinder surrounds the crucible and mold, and is arranged to be evacuated.

  18. Mold Allergy

    MedlinePlus

    ... the Allergist Health Professionals Partners Media Donate Allergies Mold Allergy What Is a Mold Allergy? If you have an allergy that occurs ... or basement. What Are the Symptoms of a Mold Allergy? The symptoms of mold allergy are very ...

  19. Organic materials for ceramic molding processes

    NASA Technical Reports Server (NTRS)

    Saito, K.

    1984-01-01

    Ceramic molding processes are examined. Binders, wetting agents, lubricants, plasticizers, surface active agents, dispersants, etc., for pressing, rubber pressing, sip casting, injection casting, taping, extrusion, etc., are described, together with forming machines.

  20. Mathematical Modeling of Heat Transfer in Mold Copper Coupled with Cooling Water During the Slab Continuous Casting Process

    NASA Astrophysics Data System (ADS)

    Xie, Xin; Chen, Dengfu; Long, Haijun; Long, Mujun; Lv, Kui

    2014-12-01

    The heat transfer in mold copper plays an important role in the solidification behavior of steel. In this study, a three-dimensional heat transfer model coupled with flow behavior of the cooling water was established to analyze the temperature field of the copper and water slots. And this model was verified by the measured temperature rise of cooling water at the inlet and outlet of slots. The advantages of this model were obtained by comparing it with Dittus-Boelter model and the Sleicher-Rouse model, which did not consider the flow of water. The results show that the Dittus-Boelter model has the highest temperature and that the coupled model has the lowest temperature. Moreover, the coupled model includes calculation of the temperature and velocity field of the cooling water inside the slots. This temperature information is very helpful for predicting the water boiling in the slots. In addition, the coupled model shows that the temperature, heat flux, and heat transfer coefficient around the water slot wall are different from the conventional models.

  1. Silicone plesiotherapy molds

    SciTech Connect

    Karolis, C.; Reay-Young, P.S.; Walsh, W.; Velautham, G.

    1983-04-01

    Plesiotherapy, the treatment of superficial lesions by radioactive molds has largely been replaced by teletherapy techniques involving high energy photon and electron beams. There are, however, situations for which a short distance type treatment, in one form or another, is superior to any other presently available. Traditionally, molds have taken the form of rigid devices incorporating clamps to attach them to the patient. This ensures a reproducible geometry about a localized region since the molds are applied on a daily basis. To make such devices requires considerable skill and patience. This article describes an alternative method that eliminates the use of cumbersome devices in many situations. Silicone molds made from a plaster cast model have been found suitable for the treatment of surface lesions and especially for lesions in the oral and nasal cavities. With the use of radioactive gold seeds the molds may be left in place for a few days without fear of them moving.

  2. Method for casting polyethylene pipe

    NASA Technical Reports Server (NTRS)

    Elam, R. M., Jr.

    1973-01-01

    Short lengths of 7-cm ID polyethylene pipe are cast in a mold which has a core made of room-temperature-vulcanizable (RTV) silicone. Core expands during casting and shrinks on cooling to allow for contraction of the polyethylene.

  3. Advances in aluminum casting technology

    SciTech Connect

    Tiryakioglu, M.; Campbell, J.

    1998-01-01

    This symposium focuses on the improvements of aluminum casting quality and reliability through a better understanding of processes and process variables, and explores the latest innovations in casting-process design that allow increasing use of the castings to replace complex assemblies and heavy steel and cast-iron components in aerospace and automotive applications. Presented are 35 papers by international experts in the various aspects of the subject. The contents include: Semisolid casting; Computer-aided designing of molds and castings; Casting-process modeling; Aluminum-matrix composite castings; HIPing of castings; Progress in the US car project; Die casting and die design; and Solidification and properties.

  4. CENTRIFUGAL CASTING MACHINE

    DOEpatents

    Shuck, A.B.

    1958-04-01

    A device is described that is specifically designed to cast uraniumn fuel rods in a vacuunn, in order to obtain flawless, nonoxidized castings which subsequently require a maximum of machining or wastage of the expensive processed material. A chamber surrounded with heating elements is connected to the molds, and the entire apparatus is housed in an airtight container. A charge of uranium is placed in the chamber, heated, then is allowed to flow into the molds While being rotated. Water circulating through passages in the molds chills the casting to form a fine grained fuel rod in nearly finished form.

  5. HUNTER 20 MATCHPLATE MOLDING MACHINE, OPERATING THE SAME AS THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    HUNTER 20 MATCHPLATE MOLDING MACHINE, OPERATING THE SAME AS THE HUNTER 10 AND OTHER HUNTER 20 COMPRESSES BOTH MOLD HALVES OVER A DOUBLE-SIDED MATCH PLATE PATTERN. DENNIS GRAY TESTS A MOLD'S HARDNESS TO ENSURE SAND MIXTURE AND MACHINE COMPRESSIBILITY ARE CORRECT. - Southern Ductile Casting Company, Casting, 2217 Carolina Avenue, Bessemer, Jefferson County, AL

  6. MOLDING APPARATUS

    DOEpatents

    Fleming, P.G.

    1963-10-01

    Molding apparatus capable of coating multiple elements each molding cycle is described. The apparatus comprises a centrally disposed reservoir penetrated by a plurality of circumferentially arranged and radially extending passageways. These passageways, in turn, communicate with passages in a separable annular member that retains selectively configured molds and mold seating arrangements. Each mold, which is readily removable from its respective seat, is adapted to retain an element therein in spaced relation to the interior of the mold by utilizing element positioning means within the mold seat and the mold so that coating material may flow about the entire outer surface of the element. (AEC)

  7. Mold Materials For Permanent Molding of Aluminum Alloys

    SciTech Connect

    John F Wallace; David Schwam; Wen Hong dxs11@po.cwru.edu

    2001-09-14

    A test that involves immersion of the potential mod materials for permanent molds has been developed that provides a thermal cycle that is similar to the experienced during casting of aluminum in permanent molds. This test has been employed to determine the relative thermal fatigue resistance of several different types of mold materials. Four commercial mold coatings have been evaluated for their insulating ability, wear resistance and roughness. The results indicate that composition and structure of the mold materials have considerable effect on their thermal fatigue cracking behavior. Irons with a gray iron structure are the most prone to thermal fatigue cracking followed by compacted graphite irons with the least thermal fatigue cracking of the cast irons experienced by ductile iron. The composition of these various irons affects their behavior.

  8. RUN OUTS OCCUR WHEN IRON HAS UNSEATED MOLDING SAND AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    RUN OUTS OCCUR WHEN IRON HAS UNSEATED MOLDING SAND AND RUN OUT OF THE MOLD UNDER POURING JACKETS AND SPILLS ONTO THE MOLDING PLATFORM. WORKERS GENERALLY WAIT SEVERAL MINUTES FOR THE IRON TO SOLIDIFY AND, WHILE IT IS STILL RED-HOT, REMOVE IT FROM THE PLATFORM AND SCRAP THE MOLD. - Southern Ductile Casting Company, Centerville Foundry, 101 Airport Road, Centreville, Bibb County, AL

  9. INTERIOR VIEW, GRAY IRON MOLDING MACHINE WITH MOLDER, R. L. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW, GRAY IRON MOLDING MACHINE WITH MOLDER, R. L. BRANDY MOLDING A RAIL CASTING (LAWLER NO. 1337, A 16' x 35' MOLD WITH A 5' COPE AND A 4' DRAG). DRAG IS FILLED WITH SAND. - Lawler Machine & Foundry Company, Molding Area, 760 North Forty-fourth Street, Birmingham, Jefferson County, AL

  10. Slip-Cast Superconductive Parts

    NASA Technical Reports Server (NTRS)

    Wise, Stephanie A.; Buckley, John D.; Vasquez, Peter; Buck, Gregory M.; Hicks, Lana P.; Hooker, Matthew W.; Taylor, Theodore D.

    1993-01-01

    Complex shapes fabricated without machining. Nonaqueous slip-casting technique used to form complexly shaped parts from high-temperature superconductive materials like YBa(2)Cu(3)O(7-delta). Such parts useful in motors, vibration dampers, and bearings. In process, organic solvent used as liquid medium. Ceramic molds made by lost-wax process used instead of plaster-of-paris molds, used in aqueous slip-casting but impervious to organic solvents and cannot drain away liquid medium. Organic-solvent-based castings do not stick to ceramic molds as they do to plaster molds.

  11. ENVIRONMENTAL ASSESSMENT OF IRON CASTING

    EPA Science Inventory

    Sampling of ductile iron casting in green sand molds with phenolic isocyanate cores and in phenol-formaldehyde bound shell molds did not provide definitive proof that environmentally hazardous organic emission occur. Both molding systems produced the same type of major emissions,...

  12. Method of casting aerogels

    DOEpatents

    Poco, J.F.

    1993-09-07

    The invention describes a method for making monolithic castings of transparent silica aerogel with densities in the range from 0.001 g/cm[sup 3] to 0.6 g/cm[sup 3]. Various shapes of aerogels are cast in flexible polymer molds which facilitate removal and eliminate irregular surfaces. Mold dimensions are preselected to account for shrinkage of aerogel which occurs during the drying step of supercritical extraction of solvent. 2 figures.

  13. Method of casting aerogels

    DOEpatents

    Poco, John F.

    1993-01-01

    The invention describes a method for making monolithic castings of transparent silica aerogel with densities in the range from 0.001 g/cm.sup.3 to 0.6 g/cm.sup.3. Various shapes of aerogels are cast in flexible polymer molds which facilitate removal and eliminate irregular surfaces. Mold dimensions are preselected to account for shrinkage of alcogel which occurs during the drying step of supercritical extraction of solvent.

  14. TRUFLO GONDOLA, USED WITH THE HUNTER 10 MOLDING MACHINE, OPERATES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    TRUFLO GONDOLA, USED WITH THE HUNTER 10 MOLDING MACHINE, OPERATES THE SAME AS THE TWO LARGER TRUFLOS USED IN CONJUNCTION WITH THE TWO HUNTER 20S. EACH GONDOLA IS CONNECTED TO THE NEXT AND RIDES ON A SINGLE TRACK RAIL FROM MOLDING MACHINES THROUGH POURING AREAS CARRYING A MOLD AROUND TWICE BEFORE THE MOLD IS PUSHED OFF ONTO A VIBRATING SHAKEOUT CONVEYOR. - Southern Ductile Casting Company, Casting, 2217 Carolina Avenue, Bessemer, Jefferson County, AL

  15. Casting methods

    DOEpatents

    Marsden, Kenneth C.; Meyer, Mitchell K.; Grover, Blair K.; Fielding, Randall S.; Wolfensberger, Billy W.

    2012-12-18

    A casting device includes a covered crucible having a top opening and a bottom orifice, a lid covering the top opening, a stopper rod sealing the bottom orifice, and a reusable mold having at least one chamber, a top end of the chamber being open to and positioned below the bottom orifice and a vacuum tap into the chamber being below the top end of the chamber. A casting method includes charging a crucible with a solid material and covering the crucible, heating the crucible, melting the material, evacuating a chamber of a mold to less than 1 atm absolute through a vacuum tap into the chamber, draining the melted material into the evacuated chamber, solidifying the material in the chamber, and removing the solidified material from the chamber without damaging the chamber.

  16. Crystallization Kinetics and Mechanism of CaO-Al2O3-Based Mold Flux for Casting High-Aluminum TRIP Steels

    NASA Astrophysics Data System (ADS)

    Shi, Cheng-Bin; Seo, Myung-Duk; Wang, Hui; Cho, Jung-Wook; Kim, Seon-Hyo

    2015-02-01

    Non-isothermal crystallization of the newly developed lime-alumina-based mold fluxes was investigated using differential scanning calorimetry. The crystallization kinetic parameters were determined by Ozawa equation, the combined Avrami-Ozawa equation, and the differential iso-conversional method of Friedman. It was found that Ozawa method failed to describe the non-isothermal crystallization behavior of the mold fluxes. The Avrami exponent determined by the combined Avrami-Ozawa equation indicates that the crystallization of cuspidine occurs through bulk nucleation and reaction-controlled three-dimensional growth, and then transforms to reaction-controlled two-dimensional growth at the crystallization later stage in lime-alumina-based mold fluxes with higher B2O3 content. For the mold fluxes with lower B2O3 content (10.8 mass pct), the crystallization of cuspidine is bulk nucleation and reaction-controlled two-dimensional growth at the crystallization primary stage followed by a diffusion-controlled two-dimensional growth process. The crystallization of CaF2 in mold flux originates from bulk nucleation and diffusion-controlled three-dimensional growth, which then transforms to two-dimensional growth. FE-SEM observations support these kinetic analysis results. The effective activation energy for cuspidine crystallization in the mold flux with higher B2O3 and Na2O contents increases as the crystallization progresses, and then decreases at the relative degree of crystallinity greater than 60 pct. The transition point of this trend approximately corresponds to the relative degree of crystallinity at which the crystallization mode of cuspidine transforms. For the mold fluxes with lower B2O3 and Na2O contents, the effective activation energy for cuspidine formation varies monotonically with the increase in the relative degree of crystallinity.

  17. SHAKE OUT WORKER DUMPING COOLED MOLDS ONTO THE VIBRATING CONVEYOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    SHAKE OUT WORKER DUMPING COOLED MOLDS ONTO THE VIBRATING CONVEYOR THAT TRANSPORTS SAND AND CASTINGS TO THE SEPARATION SCREEN. - Southern Ductile Casting Company, Centerville Foundry, 101 Airport Road, Centreville, Bibb County, AL

  18. The Through Process Simulation of Mold filling, Solidification, and Heat Treatment of the Al Alloy Bending Beam Low-pressure Casting

    NASA Astrophysics Data System (ADS)

    Yin, Yajun; Zhou, Jianxin; Guo, Zhao; Wang, Huan; Liao, Dunming; Chen, Tao

    2015-06-01

    The research on the simulation for the through process of low-pressure casting and heat treatment is conducive to combine information technology and advanced casting technology, which will help to predict the defects and mechanical properties of the castings in the through process. In this paper, we focus on the simulation for through process of low-pressure casting and heat treatment of ZL114A Bending beam. Firstly, we analyzethe distribution of the shrinkage and porosities in filling and solidification process, and simulate the distribution of stress and strain in the late solidification of casting. Then, the numerical simulation of heat treatment process for ZL114A Bending beam is realized according to the heat treatment parameters and the corresponding simulation results of temperature field, stress, strain, and aging performance are given. Finally, we verify that simulation platform for the through process of low-pressure casting and heat treatment can serve the production practice perfectly and provide technical guidance and process optimization for the through process of low-pressure casting and heat treatment.

  19. HIGH TEMPERATURE REFRACTORY COATING FOR GRAPHITE MOLDS

    DOEpatents

    Stoddard, S.D.

    1958-10-21

    An improved foundry mold coating for use with graphite molds used in the casting of uranium is presented. The refractory mold coating serves to keep the molten uranium from contact with graphite of the mold and thus prevents carbon pickup by the molten metal. The refractory coating is made by dry mixing certain specific amounts of aluminum oxide, bentonite, Tennessee ball clay, and a soluble silicate salt. Water is then added to the mixture and the suspension thus formed is applied by spraying onto the mold.

  20. Investment casting design of experiment. Final report

    SciTech Connect

    Owens, R.

    1997-10-01

    Specific steps in the investment casting process were analyzed in a designed experiment. The casting`s sensitivity to changes in these process steps was experimentally determined Dimensional and radiographic inspection were used to judge the sensitivity of the casting. Thirty-six castings of different pedigrees were poured and measured. Some of the dimensional inspection was conducted during the processing. It was confirmed that wax fixturing, number of gates, gate location, pour and mold temperature, pour speed, and cooling profile all affected the radiographic quality of the casting. Gate and runner assembly techniques, number of gates, and mold temperature affect the dimensional quality of the casting.

  1. Constant permeability of (Fe{sub 0.75}B{sub 0.20}Si{sub 0.05}){sub 96}Nb{sub 4} bulk metallic glass prepared by B{sub 2}O{sub 3} flux melting and Cu-mold casting

    SciTech Connect

    Bitoh, T.; Shibata, D.

    2009-04-01

    The effect of B{sub 2}O{sub 3} flux melting on the soft magnetic properties of (Fe{sub 0.75}B{sub 0.20}Si{sub 0.05}){sub 96}Nb{sub 4} bulk metallic glass prepared by casting has been investigated. Ring-shaped bulk specimens that were prepared by B{sub 2}O{sub 3} flux melting and Cu-mold casting (fluxed specimens) show a flat hysteresis curve, indicating a good linear relationship between the magnetic induction and the applied magnetic field. Although the permeability of the fluxed specimens is lower than that of the specimens prepared by conventional Cu-mold casting by one order of magnitude, their coercivities are almost same. These results show that it is possible to develop a new soft magnetic material that exhibits constant permeability with low core loss.

  2. Epoxy-resin patterns speed shell-molding of aluminum parts

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Half patterns cast from commercial epoxy resin containing aluminum powder are used for shell-molding of aluminum parts. The half patterns are cast in plastic molds of the original wooden pattern. Ten serviceable sand resin molds are made from each epoxy pattern.

  3. MOLD POLLUTION

    EPA Science Inventory

    Mold pollution is the growth of molds in a building resulting in a negative impact on the use of that structure. The negative impacts generally fall into two categories: destruction of the structure itself and adverse health impacts on the building's occupants. It is estimated...

  4. Mold Charlatans.

    ERIC Educational Resources Information Center

    Woody, Daniel

    2002-01-01

    Offers a primer on toxic mold and its removal, warning against ignorant or unethical mold remediation companies and offering five considerations (checking references, considering the big picture, sampling more than the air, considering release, and considering the source) when hiring such services. (EV)

  5. Castable plastic mold with electroplatable base

    DOEpatents

    Domeier, Linda A.; Morales, Alfredo M.; Gonzales, Marcela G.; Keifer, Patrick M.

    2004-01-20

    A sacrificial plastic mold having an electroplatable backing is provided as are methods of making such a mold via the infusion of a castable liquid formulation through a porous metal substrate (sheet, screen, mesh or foam) and into the features of a micro-scale master mold. Upon casting and demolding, the porous metal substrate is embedded within the cast formulation and projects a plastic structure with features determined by the mold tool. The plastic structure provides a sacrificial plastic mold mechanically bonded to the porous metal substrate, which provides a conducting support suitable for electroplating either contiguous or non-contiguous metal replicates. After electroplating and lapping, the sacrificial plastic can be dissolved, leaving the desired metal structure bonded to the porous metal substrate. Optionally, the electroplated structures may be debonded from the porous substrate by selective dissolution of the porous substrate or a coating thereon.

  6. Inner surface roughness of complete cast crowns made by centrifugal casting machines.

    PubMed

    Ogura, H; Raptis, C N; Asgar, K

    1981-05-01

    Six variables that could affect the surface roughness of a casting were investigated. The variables were (1) type of alloy, (2) mold temperature, (3) metal casting temperature, (4) casting machine, (5) sandblasting, and (6) location of each section. It was determined that the training portion of a complete cast crown had rougher surfaces than the leading portion. Higher mold and casting temperatures produced rougher castings, and this effect was more pronounced in the case of the base metal alloy. Sandblasting reduced the roughness, but produced scratched surfaces. Sandblasting had a more pronounced affect on the surface roughness of the base metal alloy cast either at a higher mold temperature or metal casting temperature. The morphology and the roughness profile of the original cast surface differed considerably with the type of alloy used. PMID:7012322

  7. Method for casting thin metal objects

    DOEpatents

    Pehrson, Brandon P; Moore, Alan F

    2015-04-14

    Provided herein are various embodiments of systems for casting thin metal plates and sheets. Typical embodiments include layers of mold cavities that are oriented vertically for casting the metal plates. In some embodiments, the mold cavities include a beveled edge such that the plates that are cast have a beveled edge. In some embodiments, the mold cavities are filled with a molten metal through an open horizontal edge of the cavity. In some embodiments, the mold cavities are filled through one or more vertical feed orifices. Further disclosed are methods for forming a thin cast metal plate or sheet where the thickness of the cast part is in a range from 0.005 inches to 0.2 inches, and the surface area of the cast part is in a range from 16 square inches to 144 square inches.

  8. Process for slip casting textured tubular structures

    DOEpatents

    Steinlage, Greg A.; Trumble, Kevin P.; Bowman, Keith J.

    2002-01-01

    A process for centrifugal slip casting a textured hollow tube. A slip made up of a carrier fluid and a suspended powder is introduced into a porous mold which is rotated at a speed sufficient to create a centrifugal force that forces the slip radially outward toward the inner surface of the mold. The suspended powder, which is formed of particles having large dimensional aspect ratios such as particles of superconductive BSCCO, settles in a textured fashion radially outward toward the mold surface. The carrier fluid of the slip passes by capillary action radially outward around the settled particles and into the absorbent mold. A layer of mold release material is preferably centrifugally slip cast to cover the mold inner surface prior to the introduction of the BSCCO slip, and the mold release layer facilitates removal of the BSCCO greenbody from the mold without fracturing.

  9. Compound cast product and method for producing a compound cast product

    DOEpatents

    Meyer, Thomas N.; Viswanathan, Srinath

    2002-09-17

    A compound cast product is formed in a casting mold (14) having a mold cavity (16) sized and shaped to form the cast product. A plurality of injectors (24) is supported from a bottom side (26) of the casting mold (14). The injectors (24) are in fluid communication with the mold cavity (16) through the bottom side (26) of the casting mold (14). A molten material holder furnace (12) is located beneath the casting mold (14). The holder furnace (12) defines molten material receiving chambers (36) configured to separately contain supplies of two different molten materials (37, 38). The holder furnace (12) is positioned such that the injectors (24) extend downward into the receiving chamber (36). The receiving chamber (36) is separated into at least two different flow circuits (51, 52). A first molten material (37) is received in a first flow circuit (51), and a second molten material (38) is received into a second flow circuit (52). The first and second molten materials (37, 38) are injected into the mold cavity (16) by the injectors (24) acting against the force of gravity. The injectors (24) are positioned such that the first and second molten materials (37, 38) are injected into different areas of the mold cavity (16). The molten materials (37, 38) are allowed to solidify and the resulting compound cast product is removed from the mold cavity (16).

  10. A Winning Cast

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Howmet Research Corporation was the first to commercialize an innovative cast metal technology developed at Auburn University, Auburn, Alabama. With funding assistance from NASA's Marshall Space Flight Center, Auburn University's Solidification Design Center (a NASA Commercial Space Center), developed accurate nickel-based superalloy data for casting molten metals. Through a contract agreement, Howmet used the data to develop computer model predictions of molten metals and molding materials in cast metal manufacturing. Howmet Metal Mold (HMM), part of Howmet Corporation Specialty Products, of Whitehall, Michigan, utilizes metal molds to manufacture net shape castings in various alloys and amorphous metal (metallic glass). By implementing the thermophysical property data from by Auburn researchers, Howmet employs its newly developed computer model predictions to offer customers high-quality, low-cost, products with significantly improved mechanical properties. Components fabricated with this new process replace components originally made from forgings or billet. Compared with products manufactured through traditional casting methods, Howmet's computer-modeled castings come out on top.

  11. Urinary casts

    MedlinePlus

    ... Casts in the urine; Fatty casts; Red blood cell casts; White blood cell casts ... The absence of cellular casts or presence of a few hyaline casts is normal. The examples above are common measurements for results of ...

  12. Urinary casts

    MedlinePlus

    ... people with advanced kidney disease and chronic kidney failure . White blood cell (WBC) casts are more common ... Hyaline casts; Granular casts; Renal tubular epithelial casts; Waxy casts; Casts in the ...

  13. VIEW OF INTERIOR OF SOUTHERN DUCTILE CASTING COMPANY, CENTERVILLE FOUNDRY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF INTERIOR OF SOUTHERN DUCTILE CASTING COMPANY, CENTERVILLE FOUNDRY SHOWING MOLD MAKING WITH PNEWMATIC JOLT SQUEEZE COPE AND DRAG MOLDING MACHINES THAT INDIVIDUALLY MADE EITHER A COPE OR DRAG AND A SMALL WHEELED MATCHPLATE JOLT-SQUEEZE MACHINE THAT COMPRESSED AN ENTIRE MOLD AT A SINGLE TIME USING A DOUBLE-SIDED PATTERN (MATCHPLATE). ALSO SHOWN ARE RAILED PALLET CAR CONVEYORS THAT CARRIED COMPLETED MOLDS FROM MOLDING MACHINES TO POURING AREAS WHERE WORKERS USED SMALL OVERHEAD CRANE TO LIFT JACKETS AND WEIGHTS ONTO THE MOLDS TO HOLD THEM TOGETHER WHILE POURING. - Southern Ductile Casting Company, Centerville Foundry, 101 Airport Road, Centreville, Bibb County, AL

  14. CASTING METHOD AND APPARATUS

    DOEpatents

    Gray, C.F.; Thompson, R.H.

    1958-10-01

    An improved apparatus for the melting and casting of uranium is described. A vacuum chamber is positioned over the casting mold and connected thereto, and a rod to pierce the oxide skin of the molten uranium is fitted into the bottom of the melting chamber. The entire apparatus is surrounded by a jacket, and operations are conducted under a vacuum. The improvement in this apparatus lies in the fact that the top of the melting chamber is fitted with a plunger which allows squeezing of the oxide skin to force out any molten uranium remaining after the skin has been broken and the molten charge has been cast.

  15. OVERVIEW LOOKING SOUTH OF CONTAINMENT SYSTEM (TOP), SLAB CASTING MACHINE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OVERVIEW LOOKING SOUTH OF CONTAINMENT SYSTEM (TOP), SLAB CASTING MACHINE AND RUN OUT WITH TRAVELING TORCH. MACHINE IS CASTING IN TWIN MOLD. - U.S. Steel, Fairfield Works, Continuous Caster, Fairfield, Jefferson County, AL

  16. Allergies, asthma, and molds

    MedlinePlus

    Allergic rhinitis - mold ... make allergies or asthma worse are called triggers. Mold is a common trigger. When your asthma or allergies become worse due to mold, you are said to have a mold allergy. ...

  17. Application of TRIZ Theory in Patternless Casting Manufacturing Technique

    NASA Astrophysics Data System (ADS)

    Yang, Weidong; Gan, Dequan; Jiang, Ping; Tian, Yumei

    The ultimate goal of Patternless Casting Manufacturing (referred to as PCM) is how to obtain the casts by casting the sand mold directly. In the previous PCM, the resin content of sand mold is much higher than that required by traditional resin sand, so the casts obtained are difficult to be sound and qualified products, which limits the application of this technique greatly. In this paper, the TRIZ algorithm is introduced to the innovation process in PCM systematically.

  18. INGOT MOLD

    DOEpatents

    Mangold, A.J. Jr.; MaHaffey, J.W.; Reese, S.L.

    1958-04-29

    An improved ingot-mold assembly is described, consisting of a body having a cavity and a recess extending through to the bottom of the body from the cavity, and the bottom of the cavity having an internal shoulder extending downward and a plug having an external shoulder. The plug extends above the shoulders and below the bottom of the body.

  19. CIR Casting System for making transtibial sockets.

    PubMed

    Wu, Yeongchi; Casanova, Hector R; Reisinger, Kim D; Smith, William K; Childress, Dudley S

    2009-03-01

    This paper describes a new casting system for transtibial socket fabrication. Like the earlier CIR Sand Casting System, the CIR Casting System is based on the 'dilatancy' principle that is similar to the packaging process for coffee beans by which loose beans become a solid mass when a vacuum is applied. The main difference from the CIR Sand Casting System is that the CIR Casting System uses light-weight, polystyrene beads in place of silica sand as the primary material for casting the negative mold. The formed negative mold can be converted into a positive sand model for modification and socket formation. With the new plaster-less casting system, the prosthetist can fabricate a transtibial prosthesis in about one hour. It reduces the set-up cost, overall weight and size of the casting system, and increases portability for service in remote areas. The System also creates minimal waste and is energy-conserving and environmentally-friendly. PMID:19235060

  20. 10. INTERIOR VIEW WITH CORES FOR VALVE MOLDING. STOCKHAM EMPLOYEES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. INTERIOR VIEW WITH CORES FOR VALVE MOLDING. STOCKHAM EMPLOYEES REFER TO THESE CORES AS THE STAR WARS CASTINGS. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  1. 22. INTERIOR VIEW WITH INTERIOR VIEW OF MOLDING SANDS CONTROL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. INTERIOR VIEW WITH INTERIOR VIEW OF MOLDING SANDS CONTROL AND TEST LAB FOR UNIT NO. 2 GREY IRON DISAMATIC. SAND CASTING TECHNICIAN, ROY BATES, TESTS THE WEIGHT OF THE SAND, DRYS IT, AND WEIGHT IT AGAINST STANDARDS TO CALCULATE THE CORRECT MOISTURE NEEDED FOR DIFFERENT MOLDS. THE SAND MIX VARY WITH THE SIZE AND COMPOSITION OF THE CASTING. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  2. Mold filling and microhardness of 1% Fe titanium alloys.

    PubMed

    Sato, Hideki; Komatsu, Masashi; Miller, Barbara; Shimizu, Hiroshi; Fujii, Hideki; Okabe, Toru

    2004-06-01

    We examined the mold filling capacity and microhardness of two industrial 1% Fe titanium alloys: Super-TIX800 (Nippon Steel Corp.) (Fe: 0.910%, O: 0.370%, N: 0.005%) and Super-TIX800N (Nippon Steel Corp.) (Fe: 0.960%, O: 0.300%, N: 0.041%). Two wedge-shaped acrylic patterns (with 30 degrees or 15 degrees angles) were prepared. Each alloy was cast in a centrifugal casting machine. Mold filling was evaluated as the missing length between the tip of the casting and the theoretical tip. Vickers hardness of the edge of the castings was also determined. For both angles tested, there were no significant differences (p>0.05) in mold filling among these alloys and the control (CP Ti). The results of testing the microhardness near the cast surfaces indicated that the hardened reaction layers on these alloys were thinner at the edge compared to CP Ti. PMID:15287570

  3. Improved compression molding process

    NASA Technical Reports Server (NTRS)

    Heier, W. C.

    1967-01-01

    Modified compression molding process produces plastic molding compounds that are strong, homogeneous, free of residual stresses, and have improved ablative characteristics. The conventional method is modified by applying a vacuum to the mold during the molding cycle, using a volatile sink, and exercising precise control of the mold closure limits.

  4. APPARATUS AND METHOD FOR INJECTION CASTING

    DOEpatents

    Shuck, A.B.

    1960-09-13

    S>A single-chamber metal casting apparatus is described wherein molten metal in a vertically movable container can be brought directly into contact with molds. By increasing the gas pressure within the chamber the metal is forced upward into the molds.

  5. Fillability of Thin-Wall Steel Castings

    SciTech Connect

    Robert C. Voigt; Joseph Bertoletti; Andrew Kaley; Sandi Ricotta; Travis Sunday

    2002-07-30

    The use of steel components is being challenged by lighter nonferrous or cast iron components. The development of techniques for enhancing and ensuring the filability of thin-wall mold cavities is most critical for thinner wall cast steel production. The purpose of this research was to develop thin-wall casting techniques that can be used to reliably produce thin-wall castings from traditional gravity poured sand casting processes. The focus of the research was to enhance the filling behavior to prevent misrunds. Experiments were conducted to investigate the influence of various foundry variables on the filling of thin section steel castings. These variables include casting design, heat transfer, gating design, and metal fluidity. Wall thickness and pouring temperature have the greatest effect on casting fill. As wall thickness increases the volume to surface area of the casting increases, which increases the solidification time, allowing the metal to flow further in thicker sect ions. Pouring time is another significant variable affecting casting fill. Increases or decreases of 20% in the pouring time were found to have a significant effect on the filling of thin-wall production castings. Gating variables, including venting, pouring head height, and mold tilting also significantly affected thin-wall casting fill. Filters offer less turbulent, steadier flow, which is appropriate for thicker castings, but they do not enhance thin-wall casting fill.

  6. [Application to dental casting machine of the rapid heating infrared image furnace (author's transl)].

    PubMed

    Etchu, Y; Noguchi, H

    1980-10-01

    The authors tried to manufacture a casting machine in dentistry by application of the infrared image furnace with a high heating speed and an easy control of a heating temperature. This machine melts an alloy in a carbon crucible set in the furnace, held in the horizontal position. Then, the furnace is turned to the vertical position to drop a melted alloy on the casting mold, and the alloy is cast in the mold by the pressure of Argon gas. The functions of trial casting machine were follows. 1. The trial casting machine was capable of heating to 1250 degrees C within one minute under 4 kW electric power. 2. The castability of the 20% Au-Pd-Ag commercial alloy cast in all casting conditions by the trial casting machine was higher than that of Thermotrol D-2 automatic centrifugal casting machine. 3. Castings of the trial casting machine showed higher tensile strength and elongation than those of the centrifugal casting machine, and the deviation of values got by the trial casting machine was small. In particular, some casting of the trial casting machine showed three times or over elongation values as compared with those of the centrifugal casting machine. 4. When casting conditions (casting temperature, casting pressure) of the trial casting machine changed, the physical properties of castings did not change so much. However, when the mold was not prevented from heating by the furnace in casting, the elongation of castings increased. PMID:7017037

  7. Effect of casting methods on castability of pure titanium.

    PubMed

    Takahashi, J; Zhang, J Z; Okazaki, M

    1993-12-01

    Two types of patterns were tested for castability: 1) polyester mesh pattern (20mm x 22mm with 100 open squares) and 2) 20mm x 20mm wax plates 1.0 and 1.5 mm in thickness. These materials were invested using a pre-arranged commercial phosphate-bonded investment for titanium. Three different types of casting machines were selected: 1) a pressure-type casting machine with separate melting and casting chambers, 2) a pressure-type casting machine with one chamber and 3) a centrifugal-type casting machine at 3000 rpm. Pure titanium (> 99.5%) was cast into the molds at a mold temperature of 100 degrees C. The castability of mesh pattern was evaluated in terms of the number of cast segment, and the cast plate was evaluated using X-ray transparent images by a digital imaging technique. The centrifugal casting method showed the best castability among these three casting methods. PMID:8004920

  8. Clean Metal Casting

    SciTech Connect

    Makhlouf M. Makhlouf; Diran Apelian

    2002-02-05

    The objective of this project is to develop a technology for clean metal processing that is capable of consistently providing a metal cleanliness level that is fit for a given application. The program has five tasks: Development of melt cleanliness assessment technology, development of melt contamination avoidance technology, development of high temperature phase separation technology, establishment of a correlation between the level of melt cleanliness and as cast mechanical properties, and transfer of technology to the industrial sector. Within the context of the first task, WPI has developed a standardized Reduced Pressure Test that has been endorsed by AFS as a recommended practice. In addition, within the context of task1, WPI has developed a melt cleanliness sensor based on the principles of electromagnetic separation. An industrial partner is commercializing the sensor. Within the context of the second task, WPI has developed environmentally friendly fluxes that do not contain fluorine. Within the context of the third task, WPI modeled the process of rotary degassing and verified the model predictions with experimental data. This model may be used to optimize the performance of industrial rotary degassers. Within the context of the fourth task, WPI has correlated the level of melt cleanliness at various foundries, including a sand casting foundry, a permanent mold casting foundry, and a die casting foundry, to the casting process and the resultant mechanical properties. This is useful in tailoring the melt cleansing operations at foundries to the particular casting process and the desired properties of cast components.

  9. PRODUCTION OF SLIP CAST CALCIA HOLLOWWARE

    DOEpatents

    Stoddard, S.D.; Nuckolls, D.E.; Cowan, R.E.

    1963-12-31

    A method for producing slip cast calcia hollow ware in which a dense calcia grain is suspended in isobutyl acetate or a mixture of tertiary amyl alcohol and o-xylene is presented. A minor amount of triethanolamine and oleic acid is added to the suspension vehicle as viscosity adjusting agents and the suspension is cast in a plaster mold, dried, and fired. (AEC)

  10. Slip casting and nitridation of silicon powder

    NASA Astrophysics Data System (ADS)

    Seiko, Y.

    1985-03-01

    Powdered Silicon was slip-cast with a CaSO4 x 0.5H2O mold and nitrided in a N atm. containing 0 or 5 vol. % H at 1000 to 1420 deg. To remove the castings, the modeling faces were coated successively with an aq. salt soap and powdered cellulose containing Na alginate, and thus prevented the sticking problem.

  11. Slip casting and nitridation of silicon powder

    NASA Technical Reports Server (NTRS)

    Seiko, Y.

    1985-01-01

    Powdered Silicon was slip-cast with a CaSO4 x 0.5H2O mold and nitrided in a N atm. containing 0 or 5 vol. % H at 1000 to 1420 deg. To remove the castings, the modeling faces were coated successively with an aq. salt soap and powdered cellulose containing Na alginate, and thus prevented the sticking problem.

  12. DUMPING COOLED MOLDS FROM THE SHAKE OUT RAILS ONTO A ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DUMPING COOLED MOLDS FROM THE SHAKE OUT RAILS ONTO A VIBRATING CONVEYOR WHICH TRANSPORTS CASTINGS AND SAND TO A SEPARATION SCREEN WHICH SIFTS SAND ONTO BELT CONVEYORS BELOW THAT CARRY IT PAST SWITCH-ACTIVATED WATER INJECTORS TO SIMILAR SWITCH-ACTIVATED FRESH SAND ADDERS BEFORE TRANSPORTING IT TO THE SAND STORAGE BIN WHILE CASTINGS ARE EITHER MANUALLY OR SMALL CRANE LIFTED TO DEGATING AREAS. - Southern Ductile Casting Company, Centerville Foundry, 101 Airport Road, Centreville, Bibb County, AL

  13. Effect of Rotational Speeds on the Cast Tube During Vertical Centrifugal Casting Process on Appearance, Microstructure, and Hardness Behavior for Al-2Si Alloy

    NASA Astrophysics Data System (ADS)

    Shailesh Rao, A.; Tattimani, Mahantesh S.; Rao, Shrikantha S.

    2015-04-01

    The flow of molten metal plays a crucial role in determining casting quality. During rotation of the mold, melt flow around its inner circumference determines the final configurations and properties of the cast tube. In this paper, Al-2Si alloy is cast in the vertical mold at the various rotational speeds of the mold. The uniform cylinder tube is formed at a rotational speed of 1000 rpm, while before and beyond this speed, irregular-shaped cast tube is formed. Finally, fine structured grain size with high hardness value is found in uniform cast tube compared with others.

  14. Casting Freedom, 1860-1862

    ERIC Educational Resources Information Center

    Social Education, 2005

    2005-01-01

    Thomas Crawford, an American Sculptor, created the full-size figure of Freedom in clay. Molds were made, from which a full-size positive plaster model was cast in five main sections. This model is on view today in the basement rotunda of the Russell Senate Office Building. Clark Mills was a self-taught American sculptor with experience in casting…

  15. Thermo-mechanical phenomena in high speed continuous casting processes

    NASA Astrophysics Data System (ADS)

    Park, Joong Kil

    Thermo-mechanical phenomena during continuous thin slab casting have been studied with the objectives of understanding the mechanism of mold crack formation, and the effect of mold design upon the mechanical behavior of the stand. To achieve these goals, several finite element models have been developed in conjunction with a series of industrial plant trials. First, an investigation of mold crack formation in thin slab casting was undertaken to elucidate the mechanism by which cracks develop and to evaluate possible solutions to the problem. Three-dimensional finite-element thermal-stress models were developed to predict temperature, distortion, and residual stress in thin-slab casting molds, comparing funnel-shaped to parallel molds. Mold wall temperatures were obtained from POSCO in Korea and analyzed to determine the corresponding heat-flux profiles in thin-slab molds. This data was utilized in an elastic-visco-plastic analysis to investigate the deformation of the molds in service for the two different mold shapes. The results of a metallurgical investigation of mold samples containing cracks were used together with the results of the mathematical models, to determine mechanisms and to suggest solutions for the formation of mold cracks. Large cyclic inelastic strains were found in the funnel transition region just below the meniscus, due to the slightly higher temperature at that location. The cracks appear to have propagated by thermal fatigue caused by major level fluctuations. Next, two-dimensional thermo-elastic-visco-plastic analysis was performed for a horizontal slice of the solidifying strand, which moves vertically down the mold during casting. The model calculates the temperature distributions, the stresses and the strains in the solidifying shell, and the air gap between the casting mold and the solidifying strand. Model predictions were verified with an analytical solution and plant trials that were carried out during billet casting at POSCO. The

  16. Thermoset matched die molding

    NASA Astrophysics Data System (ADS)

    Young, P. R.

    Reinforced molding compounds, mat molding, preform molding, cold press molding, and various other molding processes are discussed. Particular attention is given to the bulk molding compound (BMC) and the sheet molding compound (SMC) (both of which are reinforced molding compounds) as there is an increasing use of these compounds. SMC can employ a wider range of fiber lengths and fiber content than BMC, while preserving strength. The dimensional stability of BMC and SMC is unexcelled, and their corrosion resistance is generally excellent. Both compounds are composed of resins (10-2500 poises), reinforcements (BMC-glass, asbestos, sisal; SMC-soluble binder chopped strand mat), and fillers from four chemical groups (silica and silicates, carbonates, sulfates, and oxides). Molding press designs are included.

  17. Solidification Conditions and Microstructure in Continuously Cast Aluminum

    NASA Astrophysics Data System (ADS)

    Buxmann, K.; Gold, E.

    1982-04-01

    The well-known relationship between cell size or dendrite spacing and local solidification time gives the possibility of calculating the thermal parameters of solidification from the microstructure of the as-cast product. As a basis for such calculations, the dendrite spacing of different aluminum castings (DC cast ingots of different diameters, cast in conventional and electromagnetic molds; cast strip from roll casters, belt casters, and block casters; and Properzi cast rod) has been measured through their cross sections. Based on these measurements, a qualitative discussion of the thermal conditions during the solidification of these products is given, and the influence of a variation in the casting conditions discussed.

  18. Clean ferrous casting technology research. Final technical report, September 29, 1993--December 31, 1995

    SciTech Connect

    Piwonka, T.S.

    1996-01-01

    This report details results of a 30-month program to develop methods of making clean ferrous castings, i.e., castings free of inclusions and surface defects. The program was divided into 3 tasks: techniques for producing clean steel castings, electromagnetic removal of inclusions from ferrous melts, and study of causes of metal penetration in sand molds in cast iron.

  19. Pathology-designed custom molded foot orthoses.

    PubMed

    Rosenbloom, Kevin B

    2011-01-01

    Treating patients with custom foot orthoses for common pathologies is a rewarding experience when the proper steps are taken during foot casting and custom-orthosis prescription writing. This article describes successful methods for orthoses casting and prescription writing for custom-molded orthoses for Achilles tendonitis, pes planus, hallux limitus, plantar fasciitis/heel spurs, lateral ankle instability, metatarsalgia, and pes cavus. In addition, a summary of orthotic laboratory instructions for each pathology-designed custom orthosis is provided, which should be considered by orthotic laboratories. PMID:21276525

  20. Molds in the Environment

    MedlinePlus

    ... Program in Brief Related Issues Resources Quick Links Air Pollution & Respiratory Health Air Quality Asthma Mold What's New ... ng Việt [PDF - 273 KB] Quick Links Air Pollution & Respiratory Health Air Quality Asthma Mold What's New ...

  1. Pyrotechnic filled molding powder

    DOEpatents

    Hartzel, Lawrence W.; Kettling, George E.

    1978-01-01

    The disclosure relates to thermosetting molding compounds and more particularly to a pyrotechnic filled thermosetting compound comprising a blend of unfilled diallyl phthalate molding powder and a pyrotechnic mixture.

  2. QUANTIFYING INDOOR MOLDS

    EPA Science Inventory

    There is growing awareness that indoor molds/fungi may be connected to such conditions as asthma, allergies, hemorrhaging, chronic rhinosinusitis, memory loss, and a symptom complex called sick-building-syndrome. In addition, molds cause frequently fatal nosocomical infections. ...

  3. A silicon sheet casting experiment. [for solar cell water production

    NASA Technical Reports Server (NTRS)

    Bickler, D. B.; Sanchez, L. E.; Sampson, W. J.

    1980-01-01

    The casting of silicon blanks for solar cells directly without slicing is an exciting concept. An experiment was performed to investigate the feasibility of developing a machine that casts wafers directly. A Czochralski furnace was modified to accept a graphite ingot-simulating fixture. Silicon was melted in the middle of the ingot simulator in a boron nitride mold. Sample castings showed reasonable crystal size. Solar cells were made from the cast blanks. The performance is reported.

  4. Allergies, asthma, and molds

    MedlinePlus

    ... in damp places. Outdoors, mold lives in the soil, on compost, and on plants that are damp. Keeping your house and yard drier will help control mold growth. Central heating and air-conditioning systems can help control mold. Change furnace and ...

  5. Molds for cable dielectrics

    DOEpatents

    Roose, L.D.

    1996-12-10

    Molds for use in making end moldings for high-voltage cables are described wherein the dielectric insulator of a cable is heated and molded to conform to a desired shape. As a consequence, high quality substantially bubble-free cable connectors suitable for mating to premanufactured fittings are made. 5 figs.

  6. Molds for cable dielectrics

    DOEpatents

    Roose, Lars D.

    1996-01-01

    Molds for use in making end moldings for high-voltage cables are described wherein the dielectric insulator of a cable is heated and molded to conform to a desired shape. As a consequence, high quality substantially bubble-free cable connectors suitable for mating to premanufactured fittings are made.

  7. Mold and Children's Health.

    ERIC Educational Resources Information Center

    Tuscano, Antoinette

    1998-01-01

    Mold can seriously affect the health of children with asthma or allergies. Indoor air problems related to mold can be difficult to identify, but when several students who spend time in the same classroom area show allergic symptoms, it is important to consider mold and air quality. Failure to respond promptly can have serious consequences. (SM)

  8. Mold-Resistant Construction.

    ERIC Educational Resources Information Center

    Huckabee, Christopher

    2003-01-01

    Asserts that one of the surest ways to prevent indoor air quality and mold issues is to use preventive construction materials, discussing typical resistance to dealing with mold problems (usually budget-related) and describing mold-resistant construction, which uses concrete masonry, brick, and stone and is intended to withstand inevitable…

  9. Bleach Neutralizes Mold Allergens

    ERIC Educational Resources Information Center

    Science Teacher, 2005

    2005-01-01

    Researchers at National Jewish Medical and Research Center have demonstrated that dilute bleach not only kills common household mold, but may also neutralize the mold allergens that cause most mold-related health complaints. The study, published in the Journal of Allergy and Clinical Immunology, is the first to test the effect on allergic…

  10. Effect of casting methods on accuracy of peridental restorations.

    PubMed

    Finger, W; Kota, K

    1982-06-01

    The present study has shown that the accuracy of peridental gold alloy castings depends 1) on the type of casting machine used, 2) on the diameter of the casting sprue, and 3) on the strength properties of the investment material. The dependence between the accuracy and the three factors mentioned is based on erosion of the investment mold by the inflow of the liquid casting alloy. The vacuum casting technique proved to be a more gentle casting method than centrifugal and vacuum/pressure techniques. PMID:7051263

  11. Continuous Casting of Single Crystal Ingots by the O.C.C. Process

    NASA Astrophysics Data System (ADS)

    Ohno, A.

    1986-01-01

    To prevent the nucleation of crystals on the mold wall in the continuous casting of metals, a heated mold that maintained that temperature above the solidification temperature of the cast metal was used instead of the conventional cold mold. The cooling of the ingot was conducted outside of the mold. Heat was conducted axially along the ingot from the mold zone to the cooling zone. The principle of the O.C.C. (Ohno Continuous Casting) Process® was applied to the horizontal casting and vertical (upward) casting of wire and platelike ingots of Sn and Al. The ingots consisted of a completely unidirectionally solidified structure. It was possible to obtain a long single crystal ingot as a result of the growth competition of crystals.

  12. Programmable and self-demolding microstructured molds fabricated from shape-memory polymers

    NASA Astrophysics Data System (ADS)

    Meier, Tobias; Bur, Julia; Reinhard, Maximilian; Schneider, Marc; Kolew, Alexander; Worgull, Matthias; Hölscher, Hendrik

    2015-06-01

    We introduce shape memory polymers as materials to augment molds with programmable switching between different micro and nanostructures as functional features of the mold and self-demolding properties. These polymer molds can be used for hot embossing (or nanoimprinting) and casting. Furthermore, they enable the replication of nano- and microstructures on curved surfaces as well as embedded structures like on the inside walls of a microfluidic channel. The shape memory polymer molds can be replicated from master molds fabricated by conventional techniques. We tested their durability for microfabrication processes and demonstrated the advantages of shape memory molds for hot embossing and casting by replicating microstructures with high aspect ratios and optical grade surface quality.

  13. Metallic Fuel Casting Development and Parameter Optimization Simulations

    SciTech Connect

    R.S. Fielding; J. Crapps; C. Unal; J.R. Kennedy

    2013-03-01

    One of the advantages of metallic fuel is the abilility to cast the fuel slugs to near net shape with little additional processing. However, the high aspect ratio of the fuel is not ideal for casting. EBR-II fuel was cast using counter gravity injection casting (CGIC) but, concerns have been raised concerning the feasibility of this process for americium bearing alloys. The Fuel Cycle Research and Development program has begun developing gravity casting techniques suitable for fuel production. Compared to CGIC gravity casting does not require a large heel that then is recycled, does not require application of a vacuum during melting, and is conducive to re-usable molds. Development has included fabrication of two separate benchscale, approximately 300 grams, systems. To shorten development time computer simulations have been used to ensure mold and crucible designs are feasible and to identify which fluid properties most affect casting behavior and therefore require more characterization.

  14. Inference of optimal speed for sound centrifugal casting of Al-12Si alloys

    NASA Astrophysics Data System (ADS)

    Agari, Shailesh Rao; Mukunda, P. G.; Rao, Shrikantha S.; Sudhakar, K. G.

    2011-05-01

    True centrifugal casting is a standard casting technique for the manufacture of hollow, intricate and sound castings without the use of cores. The molten metal or alloy poured into the rotating mold forms a hollow casting as the centrifugal forces lift the liquid along the mold inner surface. When a mold is rotated at low and very high speeds defects are found in the final castings. Obtaining the critical speed for sound castings should not be a matter of guess or based on experience. The defects in the casting are mainly due to the behavior of the molten metal during the teeming and solidification process. Motion of molten metal at various speeds and its effect during casting are addressed in this paper. Eutectic Al-12Si alloy is taken as an experiment fluid and its performance during various rotational speeds is discussed.

  15. Numerical study of porosity in titanium dental castings.

    PubMed

    Wu, M; Sahm, P R; Augthun, M; Spiekermann, H; Schädlich-Stubenrauch, J

    1999-09-01

    A commercial software package, MAGMASOFT (MAGMA Giessereitechnologie GmbH, Aachen, Germany), was used to study shrinkage and gas porosity in titanium dental castings. A geometrical model for two simplified tooth crowns connected by a connector bar was created. Both mold filling and solidification of this casting model were numerically simulated. Shrinkage porosity was quantitatively predicted by means of a built-in feeding criterion. The risk of gas pore formation was investigated using the numerical filling and solidification results. The results of the numerical simulations were compared with experiments, which were carried out on a centrifugal casting machine with an investment block mold. The block mold was made of SiO2 based slurry with a 1 mm thick Zr2 face coat to reduce metal-mold reactions. Both melting and casting were carried out under protective argon (40 kPa). The finished castings were sectioned and the shrinkage porosity determined. The experimentally determined shrinkage porosity coincided with the predicted numerical simulation results. No apparent gas porosity was found in these model castings. Several running and gating systems for the above model casting were numerically simulated. An optimized running and gating system design was then experimentally cast, which resulted in porosity-free castings. PMID:15348102

  16. Fluxing agent for metal cast joining

    DOEpatents

    Gunkel, Ronald W.; Podey, Larry L.; Meyer, Thomas N.

    2002-11-05

    A method of joining an aluminum cast member to an aluminum component. The method includes the steps of coating a surface of an aluminum component with flux comprising cesium fluoride, placing the flux coated component in a mold, filling the mold with molten aluminum alloy, and allowing the molten aluminum alloy to solidify thereby joining a cast member to the aluminum component. The flux preferably includes aluminum fluoride and alumina. A particularly preferred flux includes about 60 wt. % CsF, about 30 wt. % AlF.sub.3, and about 10 wt. % Al.sub.2 O.sub.3.

  17. 53. PRODUCTION MOLDS. THESE MOLDS ARE COPIES OF THE ORIGINAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    53. PRODUCTION MOLDS. THESE MOLDS ARE COPIES OF THE ORIGINAL MOLDS IN THE MORAVIAN POTTERY AND TILE WORKS COLLECTION, AND ARE USED TO PRESS TILES. THE FACTORY KEEPS TEN PRODUCTION MOLDS FOR EACH IMAGE. THE ORIGINAL MOLDS ARE NOT USED IN PRODUCTION. - Moravian Pottery & Tile Works, Southwest side of State Route 313 (Swamp Road), Northwest of East Court Street, Doylestown, Bucks County, PA

  18. Numerical simulation of centrifugal casting of pipes

    NASA Astrophysics Data System (ADS)

    Kaschnitz, E.

    2012-07-01

    A numerical simulation model for the horizontal centrifugal pipe casting process was developed with the commercial simulation package Flow3D. It considers - additionally to mass, energy and momentum conservation equations and free surface tracking - the fast radial and slower horizontal movement of the mold. The iron inflow is not steady state but time dependent. Of special importance is the friction between the liquid and the mold in connection with the viscosity and turbulence of the iron. Experiments with the mold at controlled revolution speeds were carried out using a high-speed camera. From these experiments friction coefficients for the description of the interaction between mold and melt were obtained. With the simulation model, the influence of typical process parameters (e.g. melts inflow, mold movement, melt temperature, cooling media) on the wall thickness of the pipes can be studied. The comparison to results of pipes from production shows a good agreement between simulation and reality.

  19. Casting uniform ceramics with direct coagulation

    SciTech Connect

    Graule, T.J.; Baader, F.H.; Gauckler, L.J.

    1995-06-01

    Today complex-shaped ceramic parts are mass fabricated by many different methods, two of which are slip casting and injection molding. The selection of the appropriate technique is governed by the geometric shape, the number of pieces to be manufactured, and the chemistry of the ceramic. Both slip casting and injection molding introduce imperfections in the green part, which lead to inhomogeneous microstructures in the sintered parts. A new fabrication method, direct coagulation casting (DCC), may be suitable for the mass production of complex ceramic parts with high strength and reliability. In DCC, an aqueous suspension is coagulated by a change in pH or an increase in ionic strength after casting, producing a rigid green body. The use of DCC can avoid most of the limitations of conventional shaping techniques, and it can be applied to a large variety of ceramic powders, sols, and polymers, alone or in combination.

  20. Pressure rig for repetitive casting

    NASA Technical Reports Server (NTRS)

    Vasquez, Peter (Inventor); Hutto, William R. (Inventor); Philips, Albert R. (Inventor)

    1989-01-01

    The invention is a pressure rig for repetitive casting of metal. The pressure rig performs like a piston for feeding molten metal into a mold. Pressure is applied to an expandable rubber diaphragm which expands like a balloon to force the metal into the mold. A ceramic cavity which holds molten metal is lined with blanket-type insulating material, necessitating only a relining for subsequent use and eliminating the lengthy cavity preparation inherent in previous rigs. In addition, the expandable rubber diaphragm is protected by the insulating material thereby decreasing its vulnerability to heat damage. As a result of the improved design the life expectancy of the pressure rig contemplated by the present invention is more than doubled. Moreover, the improved heat protection has allowed the casting of brass and other alloys with higher melting temperatures than possible in the conventional pressure rigs.

  1. Molded Magnetic Article

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G. (Inventor); Namkung, Min (Inventor); Wincheski, Russell A. (Inventor); Fulton, James P. (Inventor); Fox, Robert L. (Inventor)

    2000-01-01

    A molded magnetic article and fabrication method are provided. Particles of ferromagnetic material embedded in a polymer binder are molded under heat and pressure into a geometric shape. Each particle is an oblate spheroid having a radius-to-thickness aspect ratio approximately in the range of 15-30. Each oblate spheroid has flattened poles that are substantially in perpendicular alignment to a direction of the molding pressure throughout the geometric shape.

  2. Guide to Molds at School.

    ERIC Educational Resources Information Center

    Healthy Schools Network, Inc., Albany, NY.

    Asserting that molds growing in schools can be harmful to children's health and learning, this guide offers information about the issue. It provides an overview of the basics, then addresses testing, types of molds, molds and health, monitoring schools for mold, mold prevention and clean-up tips for schools, and what parents should do if they…

  3. 40 CFR Table 1 to Subpart Wwww of... - Equations To Calculate Organic HAP Emissions Factors for Specific Open Molding and Centrifugal...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Emissions Factors for Specific Open Molding and Centrifugal Casting Process Streams 1 Table 1 to Subpart... (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED... Factors for Specific Open Molding and Centrifugal Casting Process Streams ER25AU05.020 ER25AU05.021...

  4. 40 CFR Table 1 to Subpart Wwww of... - Equations To Calculate Organic HAP Emissions Factors for Specific Open Molding and Centrifugal...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Emissions Factors for Specific Open Molding and Centrifugal Casting Process Streams 1 Table 1 to Subpart... (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emissions... Specific Open Molding and Centrifugal Casting Process Streams ER25AU05.020 ER25AU05.021...

  5. 40 CFR Table 1 to Subpart Wwww of... - Equations To Calculate Organic HAP Emissions Factors for Specific Open Molding and Centrifugal...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Emissions Factors for Specific Open Molding and Centrifugal Casting Process Streams 1 Table 1 to Subpart... (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED... Factors for Specific Open Molding and Centrifugal Casting Process Streams ER25AU05.020 ER25AU05.021...

  6. 40 CFR Table 1 to Subpart Wwww of... - Equations To Calculate Organic HAP Emissions Factors for Specific Open Molding and Centrifugal...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Emissions Factors for Specific Open Molding and Centrifugal Casting Process Streams 1 Table 1 to Subpart... (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED... Factors for Specific Open Molding and Centrifugal Casting Process Streams ER25AU05.020 ER25AU05.021...

  7. Process for Making Ceramic Mold

    NASA Technical Reports Server (NTRS)

    Buck, Gregory M. (Inventor); Vasquez, Peter (Inventor)

    2001-01-01

    An improved process for slip casting molds that can be more economically automated and that also exhibits greater dimensional stability is disclosed. The process involves subjecting an investment pattern, preferably made from wax, to successive cycles of wet-dipping in a slurry of colloidal, silica-based binder and dry powder-coating, or stuccoing with plaster of Paris or calcium sulfate mixtures to produce a multi-layer shell over the pattern. The invention as claimed entails applying a primary and a secondary coating to the investment pattern. At least two wet-dipping on in a primary slurry and dry-stuccoing cycles provide the primary coating, and an additional two wet-dippings and dry-stuccoing cycles provide the secondary, or back-up, coating. The primary and secondary coatings produce a multi-layered shell pattern. The multi-layered shell pattern is placed in a furnace first to cure and harden, and then to vaporize the investment pattern, leaving a detailed, high precision shell mold.

  8. Combination Of Investment And Centrifugal Casting

    NASA Technical Reports Server (NTRS)

    Creeger, Gordon A.

    1994-01-01

    Modifications, including incorporation of centrifugal casting, made in investment-casting process reducing scrap rate. Used to make first- and second-stage high-pressure-fuel-turbopump nozzles, containing vanes with thin trailing edges and other thin sections. Investment mold spun for short time while being filled, and stopped before solidification occurs. Centrifugal force drives molten metal into thin trailing edges, ensuring they are filled. With improved filling, preheat and pour temperatures reduced and solidification hastened so less hot tearing.

  9. VIEW POURING PLATFORM SHOWING MOLD POURING JACKETS AND WEIGHTS AND, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW POURING PLATFORM SHOWING MOLD POURING JACKETS AND WEIGHTS AND, IN THE FOREGROUND, SAND RETURN FROM THE SHAKEOUT ACTUATING A SIMPLE LEVER SYSTEM THAT ADDED FRESH WATER TO THE SAND IN PREPARATION FOR ITS REUSE. - Southern Ductile Casting Company, Centerville Foundry, 101 Airport Road, Centreville, Bibb County, AL

  10. 12. VIEW OF DEPLETED URANIUM INGOT AND MOLDS. DEPLETED URANIUM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. VIEW OF DEPLETED URANIUM INGOT AND MOLDS. DEPLETED URANIUM CASTING OPERATIONS CEASED IN 1988. (11/14/57) - Rocky Flats Plant, Non-Nuclear Production Facility, South of Cottonwood Avenue, west of Seventh Avenue & east of Building 460, Golden, Jefferson County, CO

  11. Phenolic Molding Compounds

    NASA Astrophysics Data System (ADS)

    Koizumi, Koji; Charles, Ted; de Keyser, Hendrik

    Phenolic Molding Compounds continue to exhibit well balanced properties such as heat resistance, chemical resistance, dimensional stability, and creep resistance. They are widely applied in electrical, appliance, small engine, commutator, and automotive applications. As the focus of the automotive industry is weight reduction for greater fuel efficiency, phenolic molding compounds become appealing alternatives to metals. Current market volumes and trends, formulation components and its impact on properties, and a review of common manufacturing methods are presented. Molding processes as well as unique advanced techniques such as high temperature molding, live sprue, and injection/compression technique provide additional benefits in improving the performance characterisitics of phenolic molding compounds. Of special interest are descriptions of some of the latest innovations in automotive components, such as the phenolic intake manifold and valve block for dual clutch transmissions. The chapter also characterizes the most recent developments in new materials, including long glass phenolic molding compounds and carbon fiber reinforced phenolic molding compounds exhibiting a 10-20-fold increase in Charpy impact strength when compared to short fiber filled materials. The role of fatigue testing and fatigue fracture behavior presents some insight into long-term reliability and durability of glass-filled phenolic molding compounds. A section on new technology outlines the important factors to consider in modeling phenolic parts by finite element analysis and flow simulation.

  12. Rapid mold replication

    SciTech Connect

    Heestand, G.M.; Beeler, R.G. Jr.; Brown, D.L.

    1995-06-01

    The desire to reduce tooling costs have driven manufacturers to investigate new manufacturing methods and materials. In the plastics injection molding industry replicating molds to meet production needs is time consuming (up to 6 months) and costly in terms of lost business. We have recently completed a feasibility study demonstrating the capability of high rate Electron Beam Physical Vapor Deposition (EBPVD) in producing mold inserts in days, not months. In the current practice a graphite mandrel, in the shape of the insert`s negative image, was exposed to a jet of metal vapor atoms emanating from an electron beam heated source of an aluminum-bronze alloy. The condensation rate of the metal atoms on the mandrel was sufficient to allow the deposit to grow at over 30 {mu}m/min or 1.2 mils per minute. The vaporization process continued for approximately 14 hours after which the mandrel and deposit were removed from the EBPVD vacuum chamber. The mandrel and condensate were easily separated resulting in a fully dense aluminum-bronze mold insert about 2.5 cm or one inch thick. This mold was subsequently cleaned and drilled for water cooling passages and mounted on a fixture for operation in an actual injection molding machine. Results of the mold`s operation were extremely successful showing great promise for this technique. This paper describes the EBPVD feasibility demonstration in more detail and discusses future development work needed to bring this technique into practice.

  13. Casting behavior of titanium alloys in a centrifugal casting machine.

    PubMed

    Watanabe, K; Miyakawa, O; Takada, Y; Okuno, O; Okabe, T

    2003-05-01

    Since dental casting requires replication of complex shapes with great accuracy, this study examined how well some commercial titanium alloys and experimental titanium-copper alloys filled a mold cavity. The metals examined were three types of commercial dental titanium [commercially pure titanium (hereinafter noted as CP-Ti), Ti-6Al-4V (T64) and Ti-6Al-7Nb (T67)], and experimental titanium-copper alloys [3%, 5% and 10% Cu (mass %)]. The volume percentage filling the cavity was evaluated in castings prepared in a very thin perforated sheet pattern and cast in a centrifugal casting machine. The flow behavior of the molten metal was also examined using a so-called "tracer element technique." The amounts of CP-Ti and all the Ti-Cu alloys filling the cavity were similar; less T64 and T67 filled the cavity. However, the Ti-Cu alloys failed to reach the end of the cavities due to a lower fluidity compared to the other metals. A mold prepared with specially designed perforated sheets was effective at differentiating the flow behavior of the metals tested. The present technique also revealed that the more viscous Ti-Cu alloys with a wide freezing range failed to sequentially flow to the end of the cavity. PMID:12593955

  14. Silicon micro-mold

    DOEpatents

    Morales, Alfredo M.

    2006-10-24

    The present invention describes a method for rapidly fabricating a robust 3-dimensional silicon-mold for use in preparing complex metal micro-components. The process begins by depositing a conductive metal layer onto one surface of a silicon wafer. A thin photoresist and a standard lithographic mask are then used to transfer a trace image pattern onto the opposite surface of the wafer by exposing and developing the resist. The exposed portion of the silicon substrate is anisotropically etched through the wafer thickness down to conductive metal layer to provide an etched pattern consisting of a series of rectilinear channels and recesses in the silicon which serve as the silicon micro-mold. Microcomponents are prepared with this mold by first filling the mold channels and recesses with a metal deposit, typically by electroplating, and then removing the silicon micro-mold by chemical etching.

  15. 40 CFR 464.40 - Applicability; description of the zinc casting subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Applicability; description of the zinc... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Zinc Casting Subcategory § 464.40 Applicability; description of the zinc casting subcategory. The provisions of...

  16. 40 CFR 464.40 - Applicability; description of the zinc casting subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Applicability; description of the zinc... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Zinc Casting Subcategory § 464.40 Applicability; description of the zinc casting subcategory. The provisions of...

  17. Glass molding process with mold lubrication

    DOEpatents

    Davey, Richard G.

    1978-06-27

    Improvements are provided in glass forming processes of the type wherein hot metal blank molds are employed by using the complementary action of a solid film lubricant layer, of graphite dispersed in a cured thermoset organopolysiloxane, along with an overspray of a lubricating oil.

  18. Effect of mold temperature on the microstructure and corrosion properties of a 14-karat gold alloy.

    PubMed

    Koiso, Kazuo; Saito, Takahiro; Kawashima, Isao

    2012-01-01

    The objective of this research was to investigate the effect of mold temperature on grain interior and grain boundary reactions in a14-karat gold alloy. The alloy (Au-15%Ag-3%Pd-24 mass%Cu) was cast into an investment with different mold temperatures (22, 250,400, and 700°C) and then analyzed using SEM, X-ray diffraction, and potentiodynamic polarization tests. Lower mold temperatures(22 and 250°C) retarded a grain boundary reaction evidently present when using higher mold temperatures (400 and 700°C). Phase separation, which was manifested as a dual phase grain boundary nodular formation, was observed at a higher degree at 400°C mold temperature than at 700°C. The corrosion potentials of alloys cast at lower mold temperatures were more noble than those cast at higher mold temperatures, suggesting improved corrosion properties. Results of this study showed that the microstructure, crystalline phases present, and corrosion properties of 14-karat gold alloy were keenly influenced by the mold temperature, which controls and influences the cooling rate. PMID:22864223

  19. In-Situ Real Time Monitoring and Control of Mold Making and Filling Processes: Final Report

    SciTech Connect

    Mohamed Abdelrahman; Kenneth Currie

    2010-12-22

    This project presents a model for addressing several objectives envisioned by the metal casting industries through the integration of research and educational components. It provides an innovative approach to introduce technologies for real time characterization of sand molds, lost foam patterns and monitoring of the mold filling process. The technology developed will enable better control over the casting process. It is expected to reduce scrap and variance in the casting quality. A strong educational component is integrated into the research plan to utilize increased awareness of the industry professional, the potential benefits of the developed technology, and the potential benefits of cross cutting technologies.

  20. Resin film infusion mold tooling and molding method

    NASA Technical Reports Server (NTRS)

    Burgess, Roger (Inventor); Grossheim, Brian (Inventor); Mouradian, Karbis (Inventor); Thrash, Patrick J. (Inventor)

    1999-01-01

    A mold apparatus and method for resin film infusion molding including an outer mold tool having a facing sheet adapted to support a resin film and preform assembly. The facing sheet includes attachment features extending therefrom. An inner mold tool is positioned on the facing sheet to enclose the resin film and preform assembly for resin film infusion molding. The inner mold tool includes a plurality of mandrels positioned for engagement with the resin film and preform assembly. Each mandrel includes a slot formed therein. A plurality of locating bars cooperate with the slots and with the attachment features for locating the mandrels longitudinally on the outer mold tool.

  1. Development of a CFD code for casting simulation

    NASA Technical Reports Server (NTRS)

    Murph, Jesse E.

    1993-01-01

    Because of high rejection rates for large structural castings (e.g., the Space Shuttle Main Engine Alternate Turbopump Design Program), a reliable casting simulation computer code is very desirable. This code would reduce both the development time and life cycle costs by allowing accurate modeling of the entire casting process. While this code could be used for other types of castings, the most significant reductions of time and cost would probably be realized in complex investment castings, where any reduction in the number of development castings would be of significant benefit. The casting process is conveniently divided into three distinct phases: (1) mold filling, where the melt is poured or forced into the mold cavity; (2) solidification, where the melt undergoes a phase change to the solid state; and (3) cool down, where the solidified part continues to cool to ambient conditions. While these phases may appear to be separate and distinct, temporal overlaps do exist between phases (e.g., local solidification occurring during mold filling), and some phenomenological events are affected by others (e.g., residual stresses depend on solidification and cooling rates). Therefore, a reliable code must accurately model all three phases and the interactions between each. While many codes have been developed (to various stages of complexity) to model the solidification and cool down phases, only a few codes have been developed to model mold filling.

  2. 92. PRODUCTION MOLDS. THESE MOLDS ARE COPIES OF THE ORIGINAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    92. PRODUCTION MOLDS. THESE MOLDS ARE COPIES OF THE ORIGINAL MOLDS IN THE MORAVIAN POTTERY AND TILE WORKS COLLECTION, AND ARE USED TO PRESS TILES. THE FACTORY KEEPS TEN PRODUCTION MOLDS FOR EACH IMAGE. THE ORIGINAL MOLDS ARE NOT USED IN PRODUCTION. SAME VIEW AS PA-107-53. - Moravian Pottery & Tile Works, Southwest side of State Route 313 (Swamp Road), Northwest of East Court Street, Doylestown, Bucks County, PA

  3. The role of water in slip casting

    NASA Technical Reports Server (NTRS)

    Mccauley, R. A.; Phelps, G. W.

    1984-01-01

    Slips and casting are considered in terms of physical and colloidal chemistry. Casting slips are polydisperse suspensions of lyophobic particles in water, whose degree of coagulation is controlled by interaction of flocculating and deflocculating agents. Slip casting rate and viscosity are functions of temperature. Slip rheology and response to deflocculating agents varies significantly as the kinds and amounts of colloid modifiers change. Water is considered as a raw material. Various concepts of water/clay interactions and structures are discussed. Casting is a de-watering operation in which water moves from slip to cast to mold in response to a potential energy termed moisture stress. Drying is an evaporative process from a free water surface.

  4. Mold After a Disaster

    MedlinePlus

    ... Health Matters What's New Preparation & Planning Disasters & Severe Weather Earthquakes Extreme Heat Floods Hurricanes Landslides Tornadoes Tsunamis ... Disaster Mold Removal After a Disaster Disasters & Severe Weather Earthquakes Extreme Heat Floods Hurricanes Landslides Tornadoes Tsunamis ...

  5. Breaking the Mold.

    ERIC Educational Resources Information Center

    Huckabee, Christopher

    2003-01-01

    Using the example of a Texas elementary school, describes how to eliminate mold and mildew from school facilities, including discovering the problem, responding quickly, reconstructing the area, and crisis planning and prevention. (EV)

  6. Newborn head molding

    MedlinePlus

    ... molding. In: Graham JM, Sanchez-Lara PA, eds. Smiths' Recognizable Patterns of Human Deformation . 4th ed. Philadelphia, PA: Elsevier; 2016:chap 35. Smith J. Initial evaluation. In: Gleason CA, Devaskar SU, ...

  7. Energy Saving Melting andRevert Reduction Technology (E0SMARRT): Predicting Pattern Tooling and Casting Dimension for Investment Casting

    SciTech Connect

    Nick Cannell; Dr. Mark Samonds; Adi Sholapurwalla; Sam Scott

    2008-11-21

    The investment casting process is an expendable mold process where wax patterns of the part and rigging are molded, assembled, shelled and melted to produce a ceramic mold matching the shape of the component to be cast. Investment casting is an important manufacturing method for critical parts because of the ability to maintain dimensional shape and tolerances. However, these tolerances can be easily exceeded if the molding components do not maintain their individual shapes well. In the investment casting process there are several opportunities for the final casting shape to not maintain the intended size and shape, such as shrinkage of the wax in the injection tool, the modification of the shape during shell heating, and with the thermal shrink and distortion in the casting process. Studies have been completed to look at the casting and shell distortions through the process in earlier phases of this project. Dr. Adrian Sabau at Oak Ridge National Labs performed characterizations and validations of 17-4 PH stainless steel in primarily fused silica shell systems with good agreement between analysis results and experimental data. Further tasks provided material property measurements of wax and methodology for employing a viscoelastic definition of wax materials into software. The final set of tasks involved the implementation of the findings into the commercial casting analysis software ProCAST, owned and maintained by ESI Group. This included: o the transfer of the wax material property data from its raw form into separate temperature-dependent thermophysical and mechanical property datasets o adding this wax material property data into an easily viewable and modifiable user interface within the pre-processing application of the ProCAST suite, namely PreCAST o and validating the data and viscoelastic wax model with respect to experimental results

  8. Improved ceramic slip casting technique. [application to aircraft model fabrication

    NASA Technical Reports Server (NTRS)

    Buck, Gregory M. (Inventor); Vasquez, Peter (Inventor)

    1993-01-01

    A primary concern in modern fluid dynamics research is the experimental verification of computational aerothermodynamic codes. This research requires high precision and detail in the test model employed. Ceramic materials are used for these models because of their low heat conductivity and their survivability at high temperatures. To fabricate such models, slip casting techniques were developed to provide net-form, precision casting capability for high-purity ceramic materials in aqueous solutions. In previous slip casting techniques, block, or flask molds made of plaster-of-paris were used to draw liquid from the slip material. Upon setting, parts were removed from the flask mold and cured in a kiln at high temperatures. Casting detail was usually limited with this technique -- detailed parts were frequently damaged upon separation from the flask mold, as the molded parts are extremely delicate in the uncured state, and the flask mold is inflexible. Ceramic surfaces were also marred by 'parting lines' caused by mold separation. This adversely affected the aerodynamic surface quality of the model as well. (Parting lines are invariably necessary on or near the leading edges of wings, nosetips, and fins for mold separation. These areas are also critical for flow boundary layer control.) Parting agents used in the casting process also affected surface quality. These agents eventually soaked into the mold, the model, or flaked off when releasing the case model. Different materials were tried, such as oils, paraffin, and even an algae. The algae released best, but some of it remained on the model and imparted an uneven texture and discoloration on the model surface when cured. According to the present invention, a wax pattern for a shell mold is provided, and an aqueous mixture of a calcium sulfate-bonded investment material is applied as a coating to the wax pattern. The coated wax pattern is then dried, followed by curing to vaporize the wax pattern and leave a shell

  9. Effect of casting method on castability of titanium and dental alloys.

    PubMed

    Watanabe, I; Woldu, M; Watanabe, K; Okabe, T

    2000-09-01

    Titanium, once considered to be difficult to cast because of its relatively high melting point (1670 +/- 50 degrees C) and strong chemical affinity, can now be acceptably cast using newly developed casting apparatus. The objectives of this study were to examine the castability of commercially pure (CP) titanium using an ultra high-speed centrifugal casting machine and a pressure difference-type casting unit and to compare the castability of titanium with that of conventional dental casting alloys. To determine castability, two types of patterns were used: a mesh pattern of 22 x 24 mm cut polyether thread sieve, and a saucer pattern (24 mm diameter) perforated to create four T-shaped ends. The casting equipment significantly affected the mold filling of both patterns (p < 0.001). The castability indices obtained from both patterns of CP titanium cast in the centrifugal casting machine were significantly (p < 0.05) better than the indices of the castings produced in the pressure-difference casting unit. The radiographs of the saucer pattern cast in the centrifugal casting machine showed some pores that were fewer and smaller in size than the pores found in castings made in the pressure-difference unit. When the ultra high-speed centrifugal casting machine was used with the manufacturer's recommended mold material, the castability of titanium was similar to that of gold alloy or Ni-Cr alloy cast by conventional means. PMID:15348384

  10. [On deffect of cobalt-chromium-nickel alloy for dental castings (author's transl)].

    PubMed

    Nasu, T; Hikichi, H; Noguchi, H

    1978-01-01

    We studied about castability and microporosity of cobalt-chromium-nickel alloy for dental casting in various methods of fusion and casting. The combinations of fusion and casting were induction fusion and centrifugal casting, arc discharge fusion and argon gas pressure casting and oxy-acetylene flame fusion and centrifugal casting. The following results were obtained. 1. The amount of microposity was smaller, when only mold temperature was low, and as mold temperature and casting temperature were high, castability was better. 2. The arc discharge fusion and argon gas pressure casting was the best method about castability and microporosity in three methods. Second method was the induction fusion and centrifugal casting. 3. In the induction fusion and centrifugal casting, blowing arong gas of 1 l/min to molten metal to protect the metal from oxidization improved the castability the best, but amount of microporosity was large, so that it was needed to lower the mold temperature in this condition. 4. The oxyacetylene flame fusion and centrifugal casting was not suitable for the casting of Co-Cr alloy "Regalloy No. 3", for the alloy was made for the induction fusion casting. PMID:366039

  11. Controlled mold geometry for surgical deficit treatment planning.

    PubMed

    Anderson, L L; Zlotolow, I M; McCormick, B; Harrison, L B

    1995-03-01

    The relatively precise placement of brachytherapy sources afforded by stereotactic frames for brain implants is not generally achievable for other sites, which lack the fixed geometry of the cranium and its contents. An exception is a source-containing rigid mold that delivers brachytherapy when inserted securely in a surgical defect. A technique has been developed in which an acrylic mold of the region to be treated is suspended in a demountable aluminum box, which is then filled to a suitable level with dental stone to form a casting that supports the mold and that can be removed intact. First, the box is aligned on a mill table and a ball mill is used to drill three parallel holes in the acrylic mold, with precisely known locations and depths and as widely separated as possible. The spherical air cavities that result from plugging these holes with ball-milled acrylic rods become reference markers in subsequent computed tomography (CT) scans. After optimum CT-coordinate locations have been planned for 125I seeds in catheters, they are transformed to mill coordinates using a matrix developed from the known marker coordinates in the two systems. Catheter holes are then drilled with the mold in the reassembled casting and box. The method has been used to treat both recurrent maxillary cancer and recurrent orbital rhabdomyosarcoma. PMID:7596320

  12. Prediction of ALLOY SHRINKAGE FACTORS FOR THE INVESTMENT CASTING PROCESS

    SciTech Connect

    Sabau, Adrian S

    2006-01-01

    This study deals with the experimental measurements and numerical predictions of alloy shrinkage factors (SFs) related to the investment casting process. The dimensions of the A356 aluminum alloy casting were determined from the numerical simulation results of solidification, heat transfer, fluid dynamics, and deformation phenomena. The investment casting process was carried out using wax patterns of unfilled wax and shell molds that were made of fused silica with a zircon prime coat. The dimensions of the die tooling, wax pattern, and casting were measured, in order to determine the actual tooling allowances. Several numerical simulations were carried out, to assess the level of accuracy for the casting shrinkage. The solid fraction threshold, at which the transition from the fluid dynamics to the solid dynamics occurs, was found to be important in predicting shrinkage factors (SFs). It was found that accurate predictions were obtained for all measued dimensions when the shell mold was considered a deformable material.

  13. Tundish Technology for Casting Clean Steel: A Review

    NASA Astrophysics Data System (ADS)

    Sahai, Yogeshwar

    2016-03-01

    With increasing demand of high-quality clean steel, cleanliness is of paramount importance in steel production and casting. Tundish plays an important role in controlling the continuously cast steel quality as it links a batch vessel, ladle, to a continuous casting mold. Tundish is also the last vessel in which metal flows before solidifying in mold. For controlling the quality of steel, flow and temperature control of the melt are critical, and these are presented in this paper. Use of proper flux, design of flow control devices, and gas injection in tundish become important factors in casting clean steel. Recycling of hot tundish, centrifugal flow tundish, H-shaped tundish, etc. are some of the developments which were implemented to cast clean steel and these are discussed.

  14. Tundish Technology for Casting Clean Steel: A Review

    NASA Astrophysics Data System (ADS)

    Sahai, Yogeshwar

    2016-08-01

    With increasing demand of high-quality clean steel, cleanliness is of paramount importance in steel production and casting. Tundish plays an important role in controlling the continuously cast steel quality as it links a batch vessel, ladle, to a continuous casting mold. Tundish is also the last vessel in which metal flows before solidifying in mold. For controlling the quality of steel, flow and temperature control of the melt are critical, and these are presented in this paper. Use of proper flux, design of flow control devices, and gas injection in tundish become important factors in casting clean steel. Recycling of hot tundish, centrifugal flow tundish, H-shaped tundish, etc. are some of the developments which were implemented to cast clean steel and these are discussed.

  15. Magnetohydrodynamic calculation of in-mold electromagnetic stirring

    SciTech Connect

    Fujisaki, Keisuke; Ueyama, Takatsugu; Okazawa, Kensuke

    1997-03-01

    The in-mold electromagnetic stirring is used to control the initial solidification of molten steel of the continuous casting. To get the optimal operation of in-mold electromagnetic stirring through the fundamental characteristics, the authors did the magnetohydrodynamic calculation. The electromagnetic force has the eddy distribution through the electromagnetic analysis in case of the rotating stirring mode which is thought to give the uniform velocity at surface. However, it does not much influence on the fluid dynamics, because the inertial effect and the continuity are large enough.

  16. Numerical Simulation and Cold Modeling experiments on Centrifugal Casting

    NASA Astrophysics Data System (ADS)

    Keerthiprasad, Kestur Sadashivaiah; Murali, Mysore Seetharam; Mukunda, Pudukottah Gopaliengar; Majumdar, Sekhar

    2011-02-01

    In a centrifugal casting process, the fluid flow eventually determines the quality and characteristics of the final product. It is difficult to study the fluid behavior here because of the opaque nature of melt and mold. In the current investigation, numerical simulations of the flow field and visualization experiments on cold models have been carried out for a centrifugal casting system using horizontal molds and fluids of different viscosities to study the effect of different process variables on the flow pattern. The effects of the thickness of the cylindrical fluid annulus formed inside the mold and the effects of fluid viscosity, diameter, and rotational speed of the mold on the hollow fluid cylinder formation process have been investigated. The numerical simulation results are compared with corresponding data obtained from the cold modeling experiments. The influence of rotational speed in a real-life centrifugal casting system has also been studied using an aluminum-silicon alloy. Cylinders of different thicknesses are cast at different rotational speeds, and the flow patterns observed visually in the actual castings are found to be similar to those recorded in the corresponding cold modeling experiments. Reasonable agreement is observed between the results of numerical simulation and the results of cold modeling experiments with different fluids. The visualization study on the hollow cylinders produced in an actual centrifugal casting process also confirm the conclusions arrived at from the cold modeling experiments and numerical simulation in a qualitative sense.

  17. Precision Casting via Advanced Simulation and Manufacturing

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A two-year program was conducted to develop and commercially implement selected casting manufacturing technologies to enable significant reductions in the costs of castings, increase the complexity and dimensional accuracy of castings, and reduce the development times for delivery of high quality castings. The industry-led R&D project was cost shared with NASA's Aerospace Industry Technology Program (AITP). The Rocketdyne Division of Boeing North American, Inc. served as the team lead with participation from Lockheed Martin, Ford Motor Company, Howmet Corporation, PCC Airfoils, General Electric, UES, Inc., University of Alabama, Auburn University, Robinson, Inc., Aracor, and NASA-LeRC. The technical effort was organized into four distinct tasks. The accomplishments reported herein. Task 1.0 developed advanced simulation technology for core molding. Ford headed up this task. On this program, a specialized core machine was designed and built. Task 2.0 focused on intelligent process control for precision core molding. Howmet led this effort. The primary focus of these experimental efforts was to characterize the process parameters that have a strong impact on dimensional control issues of injection molded cores during their fabrication. Task 3.0 developed and applied rapid prototyping to produce near net shape castings. Rocketdyne was responsible for this task. CAD files were generated using reverse engineering, rapid prototype patterns were fabricated using SLS and SLA, and castings produced and evaluated. Task 4.0 was aimed at developing technology transfer. Rocketdyne coordinated this task. Casting related technology, explored and evaluated in the first three tasks of this program, was implemented into manufacturing processes.

  18. Predicting Pattern Tooling and Casting Dimensions for Investment Casting - Phase II

    SciTech Connect

    Sabau, Adrian S

    2005-09-01

    The investment casting process allows the production of complex-shape parts and close dimensional tolerances. One of the most important phases in the investment casting process is the design of the pattern die. Pattern dies are used to create wax patterns by injecting wax into dies. The wax patterns are used to create a ceramic shell by the application of a series of ceramic coatings, and the alloy is cast into the dewaxed shell mold (Fig. 1.1). However, the complexity of shape and the close dimensional tolerances required in the final casting make it difficult to determine tooling dimensions. The final linear dimension of the casting depends on the cumulative effects of the linear expansions or contractions in each step of the investment casting process (Fig. 1.2). In most cases, the mold geometry or cores restrict the shrinkage of the pattern or the cast part, and the final casting dimensions may be affected by time-dependent processes such as viscoelastic deformation of the wax, and viscoplastic creep and plastic deformations of the shell and alloy. The pattern die is often reworked several times to produce castings whose dimensions are within acceptable tolerances. To date, investment casting technology has been based on hands-on training and experience. Technical literature is limited to experimental, phenomenological studies aimed at obtaining empirical correlations for quick and easy application in industry. The goal of this project was to predict casting dimensions for investment castings in order to meet blueprint nominal during the first casting run. Several interactions have to be considered in a coupled manner to determine the shrinkage factors: these are the die-wax, wax-shell, and shell-alloy interactions (as illustrated in Fig. 1.3). In this work, the deformations of the die-wax and shell-alloy systems were considered in a coupled manner, while the coupled deformation of the wax-shell system was not considered. Future work is needed in order to

  19. Lost-Wax Casting in Ancient China: New Discussion on Old Debates

    NASA Astrophysics Data System (ADS)

    Zhou, Weirong; Huang, Wei

    2015-07-01

    The possible use of lost-wax casting in China has long been a matter of controversy. Based on the study of pertinent ancient texts concerning the technical origins of lost-wax casting in China, direct examination of questioned ancient Chinese bronzes as well as definite lost-wax castings from both overseas and China, and modern production of objects using piece-mold casting, the authors point out their own conceptual ideas about ancient lost-wax casting as follows. First, the lost-wax casting technique does not have its earliest origins in ancient China but rather from the Sumerians in Mesopotamia, where it was predominantly used to cast small human and animal figures (statuettes). Next, some essential characteristics of the lost-wax casting technique can be identified from the point of view of a distortable soft starting model. The locally deformed shape of lost-wax castings is found to be variable. Finally, it is improper to consider the ease of extraction from the mold as the criterion for distinguishing lost-wax casting from piece-mold casting. It is therefore incorrect to conclude that the three-dimensional openwork decorations present on Chinese bronzes from the Spring and Autumn Period, and the Warring States Period, are fabricated using lost-wax castings.

  20. Pigmented casts.

    PubMed

    Miteva, Mariya; Romanelli, Paolo; Tosti, Antonella

    2014-01-01

    Pigmented casts have been reported with variable frequency in scalp biopsies from alopecia areata, trichotillomania, chemotherapy-induced alopecia and postoperative (pressure induced) alopecia. Their presence and morphology in other scalp disorders has not been described. The authors assessed for the presence and morphology of pigmented casts in 308 transversely bisected scalp biopsies from nonscarring and scarring alopecia, referred to the Department of Dermatology, University of Miami within a year. The pigmented casts were present in 21 of 29 cases of alopecia areata (72%), 7 of 7 cases of trichotillomania (100%), 1 case of friction alopecia, 4 of 28 cases of central centrifugal cicatricial alopecia (14%), and 4 of 4 cases of dissecting cellulitis (100%). They did not show any distinguishing features except for the morphology in trichotillomania, which included twisted, linear (zip), and "button"-like pigment aggregation. The linear arrangement was found also in friction alopecia and dissecting cellulitis. Pigmented casts in the hair canals of miniaturized/vellus hairs was a clue to alopecia areata. Pigmented casts can be observed in biopsies of different hair disorders, but they are not specific for the diagnosis. Horizontal sections allow to better assess their morphology and the follicular level of presence of pigmented casts, which in the context of the other follicular findings may be a clue to the diagnosis. PMID:23823025

  1. Sub-50 nm UV-curing nanoimprint based on fluoropolymer, CYTOP, mold

    NASA Astrophysics Data System (ADS)

    Bian, Jie; Yang, Tao; Yuan, Changsheng; Ge, Haixiong; Chen, Yanfeng

    2014-07-01

    In addition to the advantages of conventional fluoropolymers (i.e., chemical resistance, optical transparency, especially low surface energy), CYTOP, a commercially available cyclic fluoropolymer, can be dissolved in a special fluorinated solvent, thus it can be coated on the substrate by a spin-coating or solution casting method. In this paper, we introduced CYTOP as a rapid prototyping mold material for UV-curing nanoimprint lithography. The CYTOP mold is fabricated by a thermal nanoimprint technique on a quartz substrate or a direct solution casting on a master mold. Nanostructures with different geometries and down to sub-50 nm feature size are faithfully duplicated by CYTOP molds through a UV-curing imprint process. The CYTOP mold preserves its lower surface energy property after 20 repeated imprint cycles and there is no peeling off problem or contamination and damage on CYTOP mold observed. However, it is found that the high aspect ratio nanostructures on the CYTOP mold are tilted or deformed after separation with the master mold.

  2. Bag molding processes

    NASA Astrophysics Data System (ADS)

    Slobodzinsky, A.

    Features, materials, and techniques of vacuum, pressure, and autoclave FRP bag molding processes are described. The bags are used in sealed environments, inflated to flexibly force a curing FRP laminate to conform to a stiff mold form which defines the shape of the finished product. Densification is achieved as the bag presses out the voids and excess resin from the laminate, and consolidation occurs as the plies and adherends are bonded by the bag pressure. Curing techniques nominally involved room temperature or high temperature, and investigations of alternative techniques, such as induction, dielectric, microwave, xenon flash, UV, electron beam, and gamma radiation heating are proceeding. Polysulfone is the most common thermoplastic. Details are given of mold preparations, peel plies or release films and fabrics, bagging techniques, and reusable venting blankets and silicone rubber bags.

  3. Processing of IN-718 Lattice Block Castings

    NASA Technical Reports Server (NTRS)

    Hebsur, Mohan G.

    2002-01-01

    Recently a low cost casting method known as lattice block casting has been developed by JAM Corporation, Wilmington, Massachusetts for engineering materials such as aluminum and stainless steels that has shown to provide very high stiffness and strength with only a fraction of density of the alloy. NASA Glenn Research Center has initiated research to investigate lattice block castings of high temperature Ni-base superalloys such as the model system Inconel-718 (IN-718) for lightweight nozzle applications. Although difficulties were encountered throughout the manufacturing process , a successful investment casting procedure was eventually developed. Wax formulation and pattern assembly, shell mold processing, and counter gravity casting techniques were developed. Ten IN-718 lattice block castings (each measuring 15-cm wide by 30-cm long by 1.2-cm thick) have been successfully produced by Hitchiner Gas Turbine Division, Milford, New Hampshire, using their patented counter gravity casting techniques. Details of the processing and resulting microstructures are discussed in this paper. Post casting processing and evaluation of system specific mechanical properties of these specimens are in progress.

  4. SIDE VIEW OF PREPARATION FOR PULLING CONTINUOUSLYCAST "CAKES" FROM MOLDS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    SIDE VIEW OF PREPARATION FOR PULLING CONTINUOUSLY-CAST "CAKES" FROM MOLDS AT #03 STATION. WHEN THE CAKES HAVE COOLED SUFFICIENTLY, THE CASTER STATION IS MOVED ASIDE TO EXPOSE THE QUENCH TANK AND MOLDS. EACH CAKE OF THE THREE CAKES WEIGHS UP TO APPROXIMATELY 20,000. THE DIMENSIONS OF BRASS CAKES RANGE UP TO 27 1\\2" WIDE X 6 3\\4" THICK X 25' LONG, CORRESPONDING MAXIMUMS FOR COPPER CAKES ARE 37 1\\2" X 5" X 24'. #01 STATION, DATING FROM THE EARLY 1960'S CASTS ONLY A SINGLE BAR (RATHER THAN THREE SIMULTANEOUSLY), THAT IS APPROXIMATELY HALF THE LENGTH OF CAKES FROM THE OTHER STATIONS (150' V. 300") AND WEIGHS UP TO 12,500 LBS. - American Brass Foundry, 70 Sayre Street, Buffalo, Erie County, NY

  5. SIDE VIEW OF PREPARATION FOR PULLING CONTINUOUSLYCAST "CAKES" FROM MOLDS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    SIDE VIEW OF PREPARATION FOR PULLING CONTINUOUSLY-CAST "CAKES" FROM MOLDS AT #03 STATION. WHEN THE CAKES HAVE COOLED SUFFICIENTLY, THE CASTER STATION IS MOVED ASIDE TO EXPOSE THE QUENCH TANK AND MOLDS. EACH CAKE OF THE THREE CAKES WEIGHS UP TO APPROXIMATELY 20,000 LBS THE DIMENSIONS OF BRASS CAKES RANGE UP TO 27 1\\2" WIDE X 6 3\\4" THICK X 25' LONG, CORRESPONDING MAXIMUMS FOR COPPER CAKES ARE 37 1\\2" X 5" X 24'. #01 STATION, DATING FROM THE EARLY 1960'S CASTS ONLY A SINGLE BAR (RATHER THAN THREE SIMULTANEOUSLY), THAT IS APPROXIMATELY HALF THE LENGTH OF CAKES FROM THE OTHER STATIONS (150' V. 300") AND WEIGHS UP TO 12,500 LBS. - American Brass Foundry, 70 Sayre Street, Buffalo, Erie County, NY

  6. End moldings for cable dielectrics

    DOEpatents

    Roose, Lars D.

    2000-01-01

    End moldings for high-voltage cables are described wherein the dielectric insulator of the cable is heated and molded to conform to a desired shape. As a consequence, high quality substantially bubble-free cable connectors suitable for mating to premanufactured fittings are made. Disclosed is a method for making the cable connectors either in the field or in a factory, molds suitable for use with the method, and the molded cable connectors, themselves.

  7. Molding process for imidazopyrrolone polymers

    NASA Technical Reports Server (NTRS)

    Johnson, C. L. (Inventor)

    1973-01-01

    A process is described for producing shaped articles of imidazopyrrolone polymers comprising molding imidazopyrrolone polymer molding power under pressure and at a temperature greater than 475 C. Moderate pressures may be employed. Preferably, prior to molding, a preform is prepared by isostatic compression. The preform may be molded at a relatively low initial pressure and temperature; as the temperature is increased to a value greater than 475 C., the pressure is also increased.

  8. Creating Cast Paper Sculpture: A Simple Lesson in Papermaking and Moldmaking. AMACO[R] Lesson.

    ERIC Educational Resources Information Center

    Gamble, Harriet; Gamble, David

    This lesson combines two significant art forms into one lesson. Students first learn the techniques necessary to create a relief sculpture terra cotta clay mold. Using that mold, students will experience the art of paper making and paper casting simply, safely, and economically. A brief history of the art of paper making is provided, along with…

  9. Method of casting articles of a bulk-solidifying amorphous alloy

    DOEpatents

    Lin, Xianghong; Johnson, William L.; Peker, Atakan

    1998-01-01

    A casting charge of a bulk-solidifying amorphous alloy is cast into a mold from a temperature greater than its crystallized melting temperature, and permitted to solidify to form an article. The oxygen content of the casting charge is limited to an operable level, as excessively high oxygen contents produce premature crystallization during the casting operation. During melting, the casting charge is preferably heated to a temperature above a threshold temperature to eliminate heterogeneous crystallization nucleation sites within the casting charge. The casting charge may be cast from above the threshold temperature, or it may be cooled to the casting temperature of more than the crystallized melting point but not more than the threshold temperature, optionally held at this temperature for a period of time, and thereafter cast.

  10. Method of casting articles of a bulk-solidifying amorphous alloy

    DOEpatents

    Lin, X.; Johnson, W.L.; Peker, A.

    1998-08-25

    A casting charge of a bulk-solidifying amorphous alloy is cast into a mold from a temperature greater than its crystallized melting temperature, and permitted to solidify to form an article. The oxygen content of the casting charge is limited to an operable level, as excessively high oxygen contents produce premature crystallization during the casting operation. During melting, the casting charge is preferably heated to a temperature above a threshold temperature to eliminate heterogeneous crystallization nucleation sites within the casting charge. The casting charge may be cast from above the threshold temperature, or it may be cooled to the casting temperature of more than the crystallized melting point but not more than the threshold temperature, optionally held at this temperature for a period of time, and thereafter cast. 8 figs.

  11. Face Coat Materials Through Sessile Drop and Investment Casting Methods

    NASA Astrophysics Data System (ADS)

    Cheng, Xu; Yuan, Chen; Blackburn, Stuart; Withey, Paul A.

    2014-06-01

    Investment casting is uniquely suited to the manufacture of Ti alloys for the production of near net-shape components, reducing material waste, and machining costs. Because of the high reactivity of titanium and its based alloy, the molds which are used in the investment casting process require high chemical inertness, which results in them being very costly and non-recyclable. In order to reduce the cost of these molds, traditionally using yttria as the face coat, two alternative molds are developed in this study with face coat materials of Y2O3-Al2O3 and Y2O3-Al2O3-ZrO2. The slurry properties and chemical inertness of the face coats were evaluated for viscosity, thermal expansion, friability, and phase development. The chemical inertness of these two molds were determined using both the sessile drop test and investment casting to identify the levels of interaction with a Ti-45Al-2Mn-2Nb-0.2B alloy. The results illustrated that the molds using Y2O3-Al2O3 and Y2O3-Al2O3-ZrO2 as the face coats both showed excellent sintering properties and chemical inertness when compared to the yttria face coat. They can consequently be used as two alternative face coats for the investment casting of TiAl alloys.

  12. MOLDED SEALING ELEMENT

    DOEpatents

    Bradford, B.W.; Skinner, W.J.

    1959-03-24

    Molded sealing elements suitable for use under conditions involving exposure to uranium hexafluoride vapor are described. Such sealing elements are made by subjecting graphitic carbons to a preliminary treatment with uranium hexafluoride vapor, and then incorporating polytetrafluorethylene in them. The resulting composition has good wear resistant and frictional properties and is resistant to disintegration by uranium hexafluoride over long periods of exposure.

  13. White Mold of Chickpea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    White mold of chickpea can occur at either seedling stage or at flowering and pod filling stages. At seedling stage, the disease occurs at the base of the stem causing symptoms like collar rot. Often white mycelial growth around the stem on soil surface is visible. Affected plants wilt and die. ...

  14. Bioreactor-free tissue engineering: directed tissue assembly by centrifugal casting.

    PubMed

    Mironov, Vladimir; Kasyanov, Vladimir; Markwald, Roger R; Prestwich, Glenn D

    2008-02-01

    Casting is a process by which a material is introduced into a mold while it is liquid, allowed to solidify in a predefined shape inside the mold, and then removed to give a fabricated object, part or casing. Centrifugal casting could be defined as a process of molding using centrifugal forces. Although the centrifugal casting technology has a long history in metal manufacturing and in the plastics industry, only recently has this technology attracted the attention of tissue engineers. Initially, centrifugation was used to optimize cell seeding on a solid scaffold. More recently, centrifugal casting has been used to create tubular scaffolds and both tubular and flat multilayered, living tissue constructs. These newer applications were enabled by a new class of biocompatible in situ crosslinkable hydrogels that mimic the extracellular matrix. Herein the authors summarize the state of the art of centrifugal casting technology in tissue engineering, they outline associated technological challenges, and they discuss the potential future for clinical applications. PMID:18194071

  15. Process and mold for molding foamed plastic articles

    SciTech Connect

    Baumrucker, E.J.

    1984-10-30

    A method for forming foamed plastic articles which includes the steps of closing a mold; prepressurizing the mold cavity with gas to prevent premature diffusion of blowing gas from the material injected into the cavity; injecting a short shot of molten synthetic resin material containing a blowing agent into the cavity; venting a portion of the prepressurization gas during the injection step; and venting the remaining prepressurization gas from the mold cavity to a vacuum chamber means to allow expansion of the injected foamable resin material within the mold cavity, the vacuum drawing the resin material throughout the mold cavity. In addition, the vacuum chamber is coupled to the mold cavity through plural spaced passageways so that the vacuum is drawn at various locations throughout the cavity to thereby enhance the complete filling of the cavity with the injected material as it expands. The mold is vented following the injection step automatically at the expiration of a predetermined time following the closing of a nozzle of the injection apparatus. A mold for carrying out the process includes improved gas flow means for delivering gas to and venting gas from the mold cavity. The mold also includes improved sealing means for sealing the mold to maintain it in a pressurized state as desired.

  16. Nonpost mold cure compound

    NASA Astrophysics Data System (ADS)

    Hirata, Akihiro

    1997-08-01

    The recent low price trend of electronic products has made IC manufacturing efficiency a top priority in the semiconductor industry. Post mold cure (PMC) process, which generally involves heating the packages in the oven at 175 C for 4 to 8 hours, takes up much longer time than most other assembly processes. If this PMC process can be reduced or eliminated, semiconductor makers will be rewarded with a much higher cost merit. We define the purpose of Non-PMC as 'to get high reliability with suitable physical and electrical properties without PMC'. We compared carious properties of molding compound before and after PMC. We found that curing reaction has almost complete through DSC and C-NMR measurement, but several properties have not stabilized yet, and that not all properties after PMC were better than before PMC. We developed new grade of molding compound considering these facts. And we found that main factors to accomplish non-PMC compound are curability and flowability, and more, increasing of fundamental properties. To accomplish non-PMC, at first, molding compound need to have very high curability. Generally speaking, too high curability causes low flowability, and causes incomplete filing, wire sweep, pad shift, and weak adhesion to inner parts of IC packages. To prevent these failures, various compound properties were studied, and we achieved in adding good flowability to very high curable molding compound. Finally, anti-popcorn property was improved by adding low moisture, high adhesion, high Tg, and high flexural strengths at high temperature. Through this study, we developed new compound grade for various package, especially large QFP using standard ECN resin.

  17. High Cost/High Risk Components to Chalcogenide Molded Lens Model: Molding Preforms and Mold Technology

    SciTech Connect

    Bernacki, Bruce E.

    2012-10-05

    This brief report contains a critique of two key components of FiveFocal's cost model for glass compression molding of chalcogenide lenses for infrared applications. Molding preforms and mold technology have the greatest influence on the ultimate cost of the product and help determine the volumes needed to select glass molding over conventional single-point diamond turning or grinding and polishing. This brief report highlights key areas of both technologies with recommendations for further study.

  18. Innovative molding technologies for the fabrication of components for microsystems

    NASA Astrophysics Data System (ADS)

    Piotter, Volker; Benzler, Tobias; Hanemann, Thomas; Woellmer, Heinz; Ruprecht, Robert; Hausselt, Juergen H.

    1999-03-01

    Economic success of microsystems technology requires a wide range of materials as well as the related manufacturing processes. A suitable technology for medium/large scale production is micro injection molding which actually allows the manufacturing of plastic microstructures with 20 microns minimum thickness, structural details of approximately 0.2 microns or maximum aspect ratios of more than 20. These microstructures are, for example, applied as components in micro optics, micro fluidics or minimally invasive surgery. This is demonstrated by microparts that are currently available or will be available soon. For higher economic efficiency and cost reduction, fully electrical injection modeling machines of higher accuracy have been applied. Also, micro insert injection molding reduces mounting costs. Manufacturing of metal or ceramic microparts by powder injection modeling allows large-scale production of complex shaped microstructures with a wide range of materials. Typical examples are sintered structured like stepped LIGA- gear wheels with minimal dimensions of 50 microns in different metal and ceramic materials. Micro Precision Casting originating from conventional investment casting is a suitable process for small/medium-scale production. Examples are microturbine housings made of precious metal alloys. An approach similar to rapid prototyping applies photocurable reactive resins. Photoinduced molding of low viscous resins under ambient conditions leads to significantly reduced cycle times. Additionally, rapid testing of new composite materials can be performed easily. Microcomponents molded from polymers and different composites like dyes with nonlinear optical properties and nanosized ceramic powders will be presented.

  19. Clean cast steel technology. Final report

    SciTech Connect

    Bates, C.E.; Griffin, J.A.

    1998-06-01

    This report documents the results obtained from the Clean Cast Steel Technology Program financially supported by the DOE Metal Casting Competitiveness Research Program and industry. The primary objective of this program is to develop technology for delivering steel free of oxide macroinclusions to mold cavities. The overall objective is to improve the quality of cast steel by developing and demonstrating the technology for substantially reducing surface and sub-surface oxide inclusions. Two approaches are discussed here. A total of 23 castings were produced by submerge pouring along with sixty conventionally poured castings. The submerged poured castings contained, on average, 96% fewer observable surface inclusions (11.9 vs 0.4) compared to the conventionally poured cast parts. The variation in the population of surface inclusions also decreased by 88% from 5.5 to 0.7. The machinability of the casting was also improved by submerged pouring. The submerge poured castings required fewer cutting tool changes and less operator intervention during machining. Subsequent to these trials, the foundry has decided to purchase more shrouds for continued experimentation on other problem castings where submerge pouring is possible. An examination of melting and pouring practices in four foundries has been carried out. Three of the four foundries showed significant improvement in casting quality by manipulating the melting practice. These melting practice variables can be grouped into two separate categories. The first category is the pouring and filling practice. The second category concerns the concentration of oxidizable elements contained in the steel. Silicon, manganese, and aluminum concentrations were important factors in all four foundries. Clean heats can consistently be produced through improved melting practice and reducing exposure of the steel to atmospheric oxygen during pouring and filling.

  20. Fabrication of Microfluidic Valves Using a Hydrogel Molding Method

    PubMed Central

    Sugiura, Yusuke; Hirama, Hirotada; Torii, Toru

    2015-01-01

    In this paper, a method for fabricating a microfluidic valve made of polydimethylsiloxane (PDMS) using a rapid prototyping method for microchannels through hydrogel cast molding is discussed. Currently, the valves in microchannels play an important role in various microfluidic devices. The technology to prototype microfluidic valves rapidly is actively being developed. For the rapid prototyping of PDMS microchannels, a method that uses a hydrogel as the casting mold has been recently developed. This technique can be used to prepare a three-dimensional structure through simple and uncomplicated methods. In this study, we were able to fabricate microfluidic valves easily using this rapid prototyping method that utilizes hydrogel cast molding. In addition, we confirmed that the valve displacement could be predicted within a range of constant pressures. Moreover, because microfluidic valves fabricated using this method can be directly observed from a cross-sectional direction, we anticipate that this technology will significantly contribute to clarifying fluid behavior and other phenomena in microchannels and microfluidic valves with complex structures. PMID:26300303

  1. Neutron radiography inspection of investment castings.

    PubMed

    Richards, W J; Barrett, J R; Springgate, M E; Shields, K C

    2004-10-01

    Investment casting, also known as the lost wax process, is a manufacturing method employed to produce near net shape metal articles. Traditionally, investment casting has been used to produce structural titanium castings for aero-engine applications with wall thickness less than 1 in (2.54 cm). Recently, airframe manufacturers have been exploring the use of titanium investment casting to replace components traditionally produced from forgings. Use of titanium investment castings for these applications reduces weight, cost, lead time, and part count. Recently, the investment casting process has been selected to produce fracture critical structural titanium airframe components. These airframe components have pushed the traditional inspection techniques to their physical limits due to cross sections on the order of 3 in (7.6 cm). To overcome these inspection limitations, a process incorporating neutron radiography (n-ray) has been developed. In this process, the facecoat of the investment casting mold material contains a cocalcined mixture of yttrium oxide and gadolinium oxide. The presence of the gadolinium oxide, allows for neutron radiographic imaging (and eventual removal and repair) of mold facecoat inclusions that remain within these thick cross sectional castings. Probability of detection (POD) studies have shown a 3 x improvement of detecting a 0.050 x 0.007 in2 (1.270 x 0.178 mm2) inclusion of this cocalcined material using n-ray techniques when compared to the POD using traditional X-ray techniques. Further, it has been shown that this n-ray compatible mold facecoat material produces titanium castings of equal metallurgical quality when compared to the traditional materials. Since investment castings can be very large and heavy, the neutron radiography facilities at the University of California, Davis McClellan Nuclear Radiation Center (UCD/MNRC) were used to develop the inspection techniques. The UCD/MNRC has very unique facilities that can handle large

  2. In Situ Observation and Investigation of Mold Flux Crystallization by Using Double Hot Thermocouple Technology

    NASA Astrophysics Data System (ADS)

    Zhou, Lejun; Wang, Wanlin; Huang, Daoyuan; Wei, Juan; Li, Jin

    2012-08-01

    The crystallization processes of mold fluxes for casting low-carbon (LC) and medium-carbon (MC) steels were investigated by using double hot thermocouple technology (DHTT) in this article. The results showed that the glass phase was first formed at the cold side thermocouple (CH-2), when the LC mold flux (mold flux for casting low-carbon steel) was exposed to the temperature gradient of 1773 K (1500 °C) to 1073 K (800 °C); then, the fine crystals were precipitated at the liquid/glass interface and grew toward glass and later on to liquid phase. However, the crystals were directly formed at CH-2 when MC flux (mold flux for casting medium-carbon steel) was under the same thermal gradient. The growth rate of MC flux crystals was much faster than that of LC ones. Scanning electron microscope (SEM) and X-ray energy dispersive spectroscopy (EDS) analyses suggested that the crystals formed in LC mold flux were mainly dendritic cuspidine Ca4Si2O7F2, and the crystals formed from the liquid phase were larger than those from the glass. For MC mold flux, the earlier precipitated crystals were large dendritic Ca4Si2O7F2, whereas the later ones were composed of equiaxed Ca2Al2SiO7 crystals. The results of DHTT measurements were consistent with the time-temperature-transformation (TTT) diagrams and X-ray diffraction (XRD) analysis.

  3. Promising method of producing cast billets from superalloys

    NASA Astrophysics Data System (ADS)

    Eremin, E. N.; Filippov, Yu. O.; Eremin, A. E.

    2010-12-01

    A new method is proposed for electroslag casting of products made of superalloys. A melt is modified by ultradispersed refractory particles, and the accumulation of a metal in a melting vessel and its pouring into a mold are performed in an argon atmosphere. The equipment designed for this method is described. The results of comparative analysis of the properties of the cast metal are presented, and the advantages of the method are shown.

  4. Project CAST.

    ERIC Educational Resources Information Center

    Charles County Board of Education, La Plata, MD. Office of Special Education.

    The document outlines procedures for implementing Project CAST (Community and School Together), a community-based career education program for secondary special education students in Charles County, Maryland. Initial sections discuss the role of a learning coordinator, (including relevant travel reimbursement and mileage forms) and an overview of…

  5. Application of Non-Arrhenius Models to the Viscosity of Mold Flux

    NASA Astrophysics Data System (ADS)

    Zhou, Lejun; Wang, Wanlin

    2016-06-01

    The mold flux in continuous casting mold experiences a significant temperature gradient ranging from more than 1773 K (1500 °C) to room temperature, and the viscosity of the mold flux would therefore have a non-Arrhenius temperature dependency in such a wide temperature region. Three non-Arrhenius models, including Vogel-Fulcher-Tammann (VFT), Adam and Gibbs (AG), and Avramov (AV), were conducted to describe the relationship between the viscosity and temperature of mold flux in the temperature gradient existing in the casting mold. It found that the results predicted by the VFT and AG models are closer to the measured ones than those by the AV model and that they are much better than the Arrhenius model in characterizing the variation of viscosity of mold flux vs temperature. In addition, the VFT temperature and AG temperature can be considered to be key benchmarks in characterizing the lubrication ability of mold flux beyond the break temperature and glass transition temperature.

  6. Probabilistic modeling of solidification grain structure in investment castings

    SciTech Connect

    Upadhya, G.K.; Yu, K.O.; Layton, M.A.; Paul, A.J.

    1995-12-31

    A probabilistic approach for modeling the evolution of grain structure in investment castings has been developed. The approach differs from the classical Monte Carlo simulations of microstructural evolution in that it uses the results from a heat transfer simulation of the investment casting process for determining the probabilities of nucleation and growth. The model was used to predict the solidification grain structure in castings. The model is quasi-3D, since it uses the information from a 3D simulation of heat transfer to predict the grain structure developed in any 2D-section of the casting. Structural transitions such as columnar/equiaxed transition can also be predicted, using suitable transition criteria. Results from the model have been validated by comparison with actual micrographs from experimental investment castings. In the first case, simulations were performed for a simple plate shaped casting of superalloy Rene 77. The effects of mold insulation as well as metal pour and mold preheat temperatures on the grain size of the casting were studied. In the second example, the casting of a complex-shaped jet engine component made of superalloy IN718 was simulated. Simulation results were seen to match very well with experiments.

  7. Advanced Pattern Material for Investment Casting Applications

    SciTech Connect

    F. Douglas Neece Neil Chaudhry

    2006-02-08

    Cleveland Tool and Machine (CTM) of Cleveland, Ohio in conjunction with Harrington Product Development Center (HPDC) of Cincinnati, Ohio have developed an advanced, dimensionally accurate, temperature-stable, energy-efficient and cost-effective material and process to manufacture patterns for the investment casting industry. In the proposed technology, FOPAT (aFOam PATtern material) has been developed which is especially compatible with the investment casting process and offers the following advantages: increased dimensional accuracy; increased temperature stability; lower cost per pattern; less energy consumption per pattern; decreased cost of pattern making equipment; decreased tooling cost; increased casting yield. The present method for investment casting is "the lost wax" process, which is exactly that, the use of wax as a pattern material, which is then melted out or "lost" from the ceramic shell. The molten metal is then poured into the ceramic shell to produce a metal casting. This process goes back thousands of years and while there have been improvements in the wax and processing technology, the material is basically the same, wax. The proposed technology is based upon an established industrial process of "Reaction Injection Molding" (RIM) where two components react when mixed and then "molded" to form a part. The proposed technology has been modified and improved with the needs of investment casting in mind. A proprietary mix of components has been formulated which react and expand to form a foam-like product. The result is an investment casting pattern with smooth surface finish and excellent dimensional predictability along with the other key benefits listed above.

  8. The potential of centrifugal casting for the production of near net shape uranium parts

    SciTech Connect

    Robertson, E.

    1993-09-01

    This report was written to provide a detailed summary of a literature survey on the near net shape casting process of centrifugal casting. Centrifugal casting is one potential casting method which could satisfy the requirements of the LANL program titled Near Net Shape Casting of Uranium for Reduced Environmental, Safety and Health Impact. In this report, centrifugal casting techniques are reviewed and an assessment of the ability to achieve the near net shape and waste minimization goals of the LANL program by using these techniques is made. Based upon the literature reviewed, it is concluded that if properly modified for operation within a vacuum, vertical or horizontal centrifugation could be used to safely cast uranium for the production of hollow, cylindrical parts. However, for the production of components of geometries other than hollow tubes, vertical centrifugation could be combined with other casting methods such as semi-permanent mold or investment casting.

  9. Method of reducing the green density of a slip cast article

    DOEpatents

    Mangels, John A.; Dickie, Ray A.

    1985-01-01

    The method disclosed in this specification is one of reducing the green density of an article cast in a slip casting operation. The article is cast from a casting slip containing silicon metal particles, yttrium containing particles, and a small amount of a fluoride salt which is effective to suppress flocculation of the silicon metal particles by y.sup.+3 ions derived from the yttrium containing particles. The method is characterized by the following step. A small amount of compound which produces a cation which will partly flocculate the particles of silicon metal is added to the casting slip. The small amount of this compound is added so that when the casting slip is slip cast into a casting mold, the partly flocculated particles of silicon will interrupt an otherwise orderly packing of the particles of silicon and particles of yttrium. In this manner, the green density of the slip cast article is reduced and the article may be more easily nitrided.

  10. Expandable pattern casting research. Phase 2, Final report, October 1, 1990--March 31, 1993

    SciTech Connect

    Not Available

    1993-12-01

    The Expandable Pattern Casting (EPC) Process is a developing foundry technology that allows designers the opportunity to consolidate parts, reduce machining, and minimize assembly operations. An air gauging system was developed for measuring foam patterns; exact shrinkage depended on type and density of the foam. Compaction studies showed that maximum sand densities in cavities and under overhangs are achieved with vibrational amplitudes 0.001--0.004 in., and that sand moved most freely within a few inches of the top free surface. Key to complete mold filling while minimizing casting defects lies in removing the foam decomposition products. The most precise iron castings were made by EPC in four commercial EPC foundries, with attention paid to molding and compaction. EP cast 60-45-12 ductile iron had yield strengths, ultimate strengths, and elastic modulus similar to conventionally cast ductile iron cast from the same ladle.

  11. Effect of casting/mould interfacial heat transfer during solidification of aluminium alloys cast in CO2-sand mould

    NASA Astrophysics Data System (ADS)

    Kulkarni, S. N.; Radhakrishna, D. K.

    2011-06-01

    The ability of heat to flow across the casting and through the interface from the casting to the mold directly affects the evolution of solidification and plays a notable role in determining the freezing conditions within the casting, mainly in foundry systems of high thermal diffusivity such as chill castings. An experimental procedure has been utilized to measure the formation process of an interfacial gap and metal-mould interfacial movement during solidification of hollow cylindrical castings of Al-4.5 % Cu alloy cast in CO2-sand mould. Heat flow between the casting and the mould during solidification of Al-4.5 % Cu alloy in CO2-sand mould was assessed using an inverse modeling technique. The analysis yielded the interfacial heat flux ( q), heat transfer coefficient ( h) and the surface temperatures of the casting and the mould during solidification of the casting. The peak heat flux was incorporated as a dimensionless number and modeled as a function of the thermal diffusivities of the casting and the mould materials. Heat flux transients were normalized with respect to the peak heat flux and modeled as a function of time. The heat flux model proposed was to estimate the heat flux transients during solidification of Al-4.5 % Cu alloy cast in CO2-sand moulds.

  12. Fabrication of Molded Magnetic Article

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G. (Inventor); Namkung, Min (Inventor); Wincheski, Russell A. (Inventor); Fox, Robert L. (Inventor)

    2001-01-01

    A molded magnetic article and fabrication method are provided. Particles of ferromagnetic material embedded in a polymer binder are molded under heat and pressure into a geometric shape. Each particle is an oblate spheroid having a radius-to-thickness aspect ratio approximately in the range of 15-30. Each oblate spheroid has flattened poles that are substantially in perpendicular alignment to a direction of the molding pressure throughout the geometric shape.

  13. Improved Sand-Compaction Method for Lost-Foam Metal Casting

    NASA Technical Reports Server (NTRS)

    Bakhtiyarov, Sayavur I.; Overfelt, Ruel A.

    2008-01-01

    An improved method of filling a molding flask with sand and compacting the sand around a refractory-coated foam mold pattern has been developed for incorporation into the lost-foam metal-casting process. In comparison with the conventional method of sand filling and compaction, this method affords more nearly complete filling of the space around the refractory-coated foam mold pattern and more thorough compaction of the sand. In so doing, this method enables the sand to better support the refractory coat under metallostatic pressure during filling of the mold with molten metal.

  14. Application of particle method to the casting process simulation

    NASA Astrophysics Data System (ADS)

    Hirata, N.; Zulaida, Y. M.; Anzai, K.

    2012-07-01

    Casting processes involve many significant phenomena such as fluid flow, solidification, and deformation, and it is known that casting defects are strongly influenced by the phenomena. However the phenomena complexly interacts each other and it is difficult to observe them directly because the temperature of the melt and other apparatus components are quite high, and they are generally opaque; therefore, a computer simulation is expected to serve a lot of benefits to consider what happens in the processes. Recently, a particle method, which is one of fully Lagrangian methods, has attracted considerable attention. The particle methods based on Lagrangian methods involving no calculation lattice have been developed rapidly because of their applicability to multi-physics problems. In this study, we combined the fluid flow, heat transfer and solidification simulation programs, and tried to simulate various casting processes such as continuous casting, centrifugal casting and ingot making. As a result of continuous casting simulation, the powder flow could be calculated as well as the melt flow, and the subsequent shape of interface between the melt and the powder was calculated. In the centrifugal casting simulation, the mold was smoothly modeled along the shape of the real mold, and the fluid flow and the rotating mold are simulated directly. As a result, the flow of the melt dragged by the rotating mold was calculated well. The eccentric rotation and the influence of Coriolis force were also reproduced directly and naturally. For ingot making simulation, a shrinkage formation behavior was calculated and the shape of the shrinkage agreed well with the experimental result.

  15. Heat-Transfer Measurements in the Primary Cooling Phase of the Direct-Chill Casting Process

    NASA Astrophysics Data System (ADS)

    Caron, Etienne J. F. R.; Baserinia, Amir R.; Ng, Harry; Wells, Mary A.; Weckman, David C.

    2012-10-01

    Thermal modeling of the direct-chill casting process requires accurate knowledge of (1) the different boundary conditions in the primary mold and secondary direct water-spray cooling regimes and (2) their variability with respect to process parameters. In this study, heat transfer in the primary cooling zone was investigated by using temperature measurements made with subsurface thermocouples in the mold as input to an inverse heat conduction algorithm. Laboratory-scale experiments were performed to investigate the primary cooling of AA3003 and AA4045 aluminum alloy ingots cast at speeds ranging between 1.58 and 2.10 mm/s. The average heat flux values were calculated for the steady-state phase of the casting process, and an effective heat-transfer coefficient for the global primary cooling process was derived that included convection at the mold surfaces and conduction through the mold wall. Effective heat-transfer coefficients were evaluated at different points along the mold height and compared with values from a previously derived computational fluid dynamics model of the direct-chill casting process that were based on predictions of the air gap thickness between the mold and ingot. The current experimental results closely matched the values previously predicted by the air gap models. The effective heat-transfer coefficient for primary cooling was also found to increase slightly with the casting speed and was higher near the mold top (up to 824 W/m2·K) where the molten aluminum first comes in contact with the mold than near the bottom (as low as 242 W/m2·K) where an air gap forms between the ingot and mold because of thermal contraction of the ingot. These results are consistent with previous studies.

  16. Low-pressure injection molding

    SciTech Connect

    Mangels, J.A. )

    1994-05-01

    Ceramic injection molding experienced a revival in the 1970s and 1980s with the application of ceramics for gas turbine components. Concurrently, techniques were being developed for the injection molding of powdered metal compositions into complex shaped articles. The impetus for the development of injection molding as a ceramic fabrication process lay in the potential to produce complex-shaped components to near-net shape. In the ceramic injection molding process, ceramic powders are processed to obtain the desired particle size, distribution and morphology and blended to obtain a homogeneous distribution. These powders are then mixed with the organic binders, generally in a heated, highshear mixer at temperatures above the melting point of the organic binders. The injection molding mix is pelletized, cooled and fed into an injection molding machine. The molding mix is reheated to a fluid state and injected under high pressure (7--70 MPa) into a die cavity. The molded part is removed from the tooling after the molding mix has solidified in the die. The organic binders are then removed from the component at temperatures up to 400 C, generally by some combination of wicking and thermal decomposition. Finally, the component is sintered to obtain its final ceramic properties, using conventional ceramic processes.

  17. Method for molding ceramic powders

    DOEpatents

    Janney, M.A.

    1990-01-16

    A method for molding ceramic powders comprises forming a slurry mixture including ceramic powder, a dispersant for the metal-containing powder, and a monomer solution. The monomer solution includes at least one multifunctional monomer, a free-radical initiator, and an organic solvent. The slurry mixture is transferred to a mold, and the mold containing the slurry mixture is heated to polymerize and crosslink the monomer and form a firm polymer-solvent gel matrix. The solid product may be removed from the mold and heated to first remove the solvent and subsequently remove the polymer, where after the product may be sintered.

  18. Method for molding ceramic powders

    DOEpatents

    Janney, Mark A.

    1990-01-01

    A method for molding ceramic powders comprises forming a slurry mixture including ceramic powder, a dispersant for the metal-containing powder, and a monomer solution. The monomer solution includes at least one multifunctional monomer, a free-radical initiator, and an organic solvent. The slurry mixture is transferred to a mold, and the mold containing the slurry mixture is heated to polymerize and crosslink the monomer and form a firm polymer-solvent gel matrix. The solid product may be removed from the mold and heated to first remove the solvent and subsequently remove the polymer, whereafter the product may be sintered.

  19. Plug replaces weld filler as seal in complex casting

    NASA Technical Reports Server (NTRS)

    Goundrey, R. L.; Harris, C. L.

    1966-01-01

    Expandable metal plug is inserted to provide a seal to support the mold core with small blocks, referred to as chaplets, during the casting of a complex volute. Weld-warpage and multiple X ray inspection are eliminated by use of this technique.

  20. Study of protective coatings for aluminum die casting molds

    NASA Astrophysics Data System (ADS)

    Peter, Ildiko; Rosso, Mario; Gobber, Federico Simone

    2015-12-01

    In this paper, the development and characterization of some protective coatings on steel substrate are presented. The coatings are realized by plasma spray techniques. The substrate material used is a Cr-Mo-V based hot work tool steel, initially submitted to vacuum heat treatment to achieve homogeneous hardness. The main attention is focused on the study of wear and on the characterization of the interface between the substrate material and the coating layer, because of their key role in determining the resistance of the coating layer. Simulation of friction and wear processes is performed by pin-on-disk test and the tested samples are observed by scanning electron microscopy.

  1. Fundamentals of Mold Free Casting: Experimental and Computational Studies

    NASA Technical Reports Server (NTRS)

    Tryggvason, Gretar; Ceccio, Steven

    1997-01-01

    Researchers are developing the technology of 'Ballistic Particle Manufacturing' (BPM) in which individual drops are precisely layered onto a substrate, and the drops are deposited so as to prevent splatting. These individual drops will ultimately be combined to form a net-shape, three-dimensional object. Our understanding of controlled drop deposition as applied to BPM is far from complete. Process parameters include the size and temperature of the liquid metal drop, its impact velocity and trajectory, and the condition and temperature of the substrate. Quantitative knowledge of the fluid mechanics and heat transfer of drop deposition and solidification are necessary to fully optimize the manufacturing process and to control the material microstructure of the final part. The object of this study is to examine the dynamics of liquid metal drops as they impinge upon a solid surface and solidify under conditions consistent with BPM (i.e. conditions which produce non-splatting drops). A program of both numerical simulations and experiments will be conducted. Questions this study will address include the following: How do the deformation and solidification of the drop depend on the properties of the fluid drop and the solid substrate? How does the presence of previously deposited drops affect the impingement and solidification process? How does the impingement of the new drop affect already deposited material? How does the cooling rate and solidification of the drops influence the material microstructure?

  2. Shrinkage Prediction for the Investment Casting of Stainless Steels

    SciTech Connect

    Sabau, Adrian S

    2007-01-01

    In this study, the alloy shrinkage factors were obtained for the investment casting of 17-4PH stainless steel parts. For the investment casting process, unfilled wax and fused silica with a zircon prime coat were used for patterns and shell molds, respectively. Dimensions of the die tooling, wax pattern, and casting were measured using a Coordinate Measurement Machine in order to obtain the actual tooling allowances. The alloy dimensions were obtained from numerical simulation results of solidification, heat transfer, and deformation phenomena. The numerical simulation results for the shrinkage factors were compared with experimental results.

  3. Filler metal alloy for welding cast nickel aluminide alloys

    DOEpatents

    Santella, M.L.; Sikka, V.K.

    1998-03-10

    A filler metal alloy used as a filler for welding cast nickel aluminide alloys contains from about 15 to about 17 wt. % chromium, from about 4 to about 5 wt. % aluminum, equal to or less than about 1.5 wt. % molybdenum, from about 1 to about 4.5 wt. % zirconium, equal to or less than about 0.01 wt. % yttrium, equal to or less than about 0.01 wt. % boron and the balance nickel. The filler metal alloy is made by melting and casting techniques such as are melting the components of the filler metal alloy and cast in copper chill molds. 3 figs.

  4. Low Cost Injection Mold Creation via Hybrid Additive and Conventional Manufacturing

    SciTech Connect

    Dehoff, Ryan R.; Watkins, Thomas R.; List, III, Frederick Alyious; Carver, Keith; England, Roger

    2015-12-01

    The purpose of the proposed project between Cummins and ORNL is to significantly reduce the cost of the tooling (machining and materials) required to create injection molds to make plastic components. Presently, the high cost of this tooling forces the design decision to make cast aluminum parts because Cummins typical production volumes are too low to allow injection molded plastic parts to be cost effective with the amortized cost of the injection molding tooling. In addition to reducing the weight of components, polymer injection molding allows the opportunity for the alternative cooling methods, via nitrogen gas. Nitrogen gas cooling offers an environmentally and economically attractive cooling option, if the mold can be manufactured economically. In this project, a current injection molding design was optimized for cooling using nitrogen gas. The various components of the injection mold tooling were fabricated using the Renishaw powder bed laser additive manufacturing technology. Subsequent machining was performed on the as deposited components to form a working assembly. The injection mold is scheduled to be tested in a projection setting at a commercial vendor selected by Cummins.

  5. Cast Aluminum Alloy for High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Lee, Jonathan A.

    2003-01-01

    Originally developed by NASA as high performance piston alloys to meet U.S. automotive legislation requiring low exhaust emission, the novel NASA alloys now offer dramatic increase in tensile strength for many other applications at elevated temperatures from 450 F (232 C) to about 750 F (400 C). It is an ideal low cost material for cast automotive components such as pistons, cylinder heads, cylinder liners, connecting rods, turbo chargers, impellers, actuators, brake calipers and rotors. It can be very economically produced from conventional permanent mold, sand casting or investment casting, with silicon content ranging from 6% to 18%. At high silicon levels, the alloy exhibits excellent dimensional stability, surface hardness and wear resistant properties.

  6. MOLD SPECIFIC QUANTITATIVE PCR: THE EMERGING STANDARD IN MOLD ANALYSIS

    EPA Science Inventory

    Today I will talk about the use of quantitative or Real time PCR for the standardized identification and quantification of molds. There are probably at least 100,000 species of molds or fungi. But there are actually about 100 typically found indoors. Some pose a threat to human...

  7. Cast aluminum denture base.

    PubMed

    Barco, M T; Dembert, M L

    1987-08-01

    The laboratory procedures for a cast aluminum base denture have been presented. If an induction casting machine is not available, the "two-oven technique" works well, provided the casting arm is kept spinning manually for 4 minutes after casting. If laboratory procedures are executed precisely and with care, the aluminum base denture can be cast with good results. PMID:3305884

  8. Processing studies in sheet molding compound compression molding

    NASA Astrophysics Data System (ADS)

    Abrams, Lisa Marie

    Due to its high strength to weight ratio, corrosion resistance, and low cost. Sheet Molding Compound (SMC) production offers great potential for growth in the automotive and trucking industry. Much attention is now being given to improving the economy of SMC compression molding by reducing the cycle time required to produce acceptable parts in steady production. One of the fastest growing applications of Sheet Molding Compound (SMC) compression molding panels is the manufacture of truck body panels. Due to their large size, the molding forces developed are substantial and have a major influence in the molding cycle. The relevant process models for SMC flow are reviewed and a procedure is developed that can be used to obtain the closing force and calculate the needed material parameters. Experiments were done using commercially made SMC varying quantities of glass, filler, and thickener to verify the validity of this model and the compression force was predicted for commercially made automotive hoods. It was found that glass and filler had a significant impact on the material parameters. When the amount of glass was increased, both material parameters m/deltan and eta increased. Similar trends were seen when increasing the amount of filler. For the thickener used in this research (magnesium oxide), it was found that it had minimal effect on the material parameters. Molding conditions and initial SMC charge configurations were also varied to see their effects on molding force and material parameters. Initial charge dimensions and volume as well as mold closing speed showed no effect on material parameters, while molding temperature showed a minimal effect. Material parameters were calculated for each SMC composition. These parameters were used to predict the compression force for the Corvette hood and Fiero hood. These predictions were compared with actual Corvette and Fiero hoods manufactured in industry. They predicted the commercially made parts quite well.

  9. Twistable mold for helicopter blades

    NASA Technical Reports Server (NTRS)

    Carter, E. S.; Kiely, E. F.

    1972-01-01

    Design is described of mold for fabrication of blades composed of sets of aerodynamic shells having same airfoil section characteristics but different distributions. Mold consists of opposing stacks of thin templates held together by long bolts. When bolts are loosened, templates can be set at different positions with respect to each other and then locked in place.

  10. Thermophilic molds: Biology and applications.

    PubMed

    Singh, Bijender; Poças-Fonseca, Marcio J; Johri, B N; Satyanarayana, Tulasi

    2016-11-01

    Thermophilic molds thrive in a variety of natural habitats including soils, composts, wood chip piles, nesting materials of birds and other animals, municipal refuse and others, and ubiquitous in their distribution. These molds grow in simple media containing carbon and nitrogen sources and mineral salts. Polyamines are synthesized in these molds and the composition of lipids varies considerably, predominantly containing palmitic, oleic and linoleic acids with low levels of lauric, palmiotoleic and stearic acids. Thermophilic molds are capable of efficiently degrading organic materials by secreting thermostable enzymes, which are useful in the bioremediation of industrial wastes and effluents that are rich in oil, heavy metals, anti-nutritional factors such as phytic acid and polysaccharides. Thermophilic molds synthesize several antimicrobial substances and biotechnologically useful miscellaneous enzymes. The analysis of genomes of thermophilic molds reveals high G:C contents, shorter introns and intergenic regions with lesser repetitive sequences, and further confirms their ability to degrade agro-residues efficiently. Genetic engineering has aided in ameliorating the characteristics of the enzymes of thermophilic molds. This review is aimed at focusing on the biology of thermophilic molds with emphasis on recent developments in the analysis of genomes, genetic engineering and potential applications. PMID:26777293

  11. STANDARDIZED MOLD IDENTIFICATION AND ENUMERATION

    EPA Science Inventory

    There are probably at least 100,000 species of molds or fungi. But there are actually about 100 typically found indoors. Some pose a threat to humans and animals and others don't. We need to know what molds are present indoors and their concentrations. The older methods of cult...

  12. INDOOR MOLDS AND ALLERGIC POTENTIAL

    EPA Science Inventory

    Rationale: Damp/moldy environments have been associated with asthma exacerbation, but mold¿s role in allergic asthma induction is less clear. Recently, 5 molds were statistically associated with water-damaged asthmatic homes in the Cleveland area. The asthma exacerbation...

  13. Steel castings by the electroslag casting technique

    NASA Astrophysics Data System (ADS)

    Sikka, V. K.; Mitchell, A.

    1984-10-01

    Electroslag casting facilities in Canada and the United States were reviewed. Several value body castings of 2 1/4 Cr-1 Mo, 9 Cr-1 Mo, and 18% Cr-8% Ni (Mo) steels were made at the University of British Columbia facility. These castings were examined for surface finish, chemical segregation, and macrostructure in the as-cast condition and after various heat treatments. Castings were subjected to tensile, charpy impact, and creep testing. Results of these tests were compared with similar data on wrought material and where applicable, with data on sand castings.

  14. Steel castings by the electroslag casting technique

    SciTech Connect

    Sikka, V.K.; Mitchell, A.

    1984-10-01

    Electroslag casting facilities in Canada and the United States were reviewed. Several valve body castings of 2 1/4 Cr-1 Mo, 9 Cr-1 Mo, and 18% Cr-8% Ni(Mo) steels were made at the University of British Columbia facility. These castings were examined for surface finish, chemical segregation, and macrostructure in the as-cast condition and after various heat treatments. Castings were subjected to tensile, Charpy impact, and creep testing. Results of these tests were compared with similar data on wrought material and, where applicable, with data on sand castings. 22 figures.

  15. Three-Dimensional Molding Based on Microstereolithography Using Beta-Tricalcium Phosphate Slurry for the Production of Bioceramic Scaffolds

    NASA Astrophysics Data System (ADS)

    Torii, Takashi; Inada, Makoto; Maruo, Shoji

    2011-06-01

    We report on a three-dimensional (3D) molding technique of fabricating bioceramic scaffolds. In this method, ceramic slurry is cast into a 3D polymer master mold, which is fabricated via microstereolithography, by a centrifugal casting method. The polymer master mold is thermally decomposed, so that a complex 3D bioceramic scaffold can be produced. In experiments, the decomposition process of the polymer model was optimized by the master decomposition curve theory to reduce harmful cracks in a green body. As a result, we could produce not only precise lattice models but also a sophisticated porous scaffold using beta-tricalcium phosphate (β-TCP) slurry. This bioceramic 3D molding technique based on microstereolithography will be useful for tailor-made tissue engineering and regeneration medicine.

  16. Multiphysics modeling of the steel continuous casting process

    NASA Astrophysics Data System (ADS)

    Hibbeler, Lance C.

    This work develops a macroscale, multiphysics model of the continuous casting of steel. The complete model accounts for the turbulent flow and nonuniform distribution of superheat in the molten steel, the elastic-viscoplastic thermal shrinkage of the solidifying shell, the heat transfer through the shell-mold interface with variable gap size, and the thermal distortion of the mold. These models are coupled together with carefully constructed boundary conditions with the aid of reduced-order models into a single tool to investigate behavior in the mold region, for practical applications such as predicting ideal tapers for a beam-blank mold. The thermal and mechanical behaviors of the mold are explored as part of the overall modeling effort, for funnel molds and for beam-blank molds. These models include high geometric detail and reveal temperature variations on the mold-shell interface that may be responsible for cracks in the shell. Specifically, the funnel mold has a column of mold bolts in the middle of the inside-curve region of the funnel that disturbs the uniformity of the hot face temperatures, which combined with the bending effect of the mold on the shell, can lead to longitudinal facial cracks. The shoulder region of the beam-blank mold shows a local hot spot that can be reduced with additional cooling in this region. The distorted shape of the funnel mold narrow face is validated with recent inclinometer measurements from an operating caster. The calculated hot face temperatures and distorted shapes of the mold are transferred into the multiphysics model of the solidifying shell. The boundary conditions for the first iteration of the multiphysics model come from reduced-order models of the process; one such model is derived in this work for mold heat transfer. The reduced-order model relies on the physics of the solution to the one-dimensional heat-conduction equation to maintain the relationships between inputs and outputs of the model. The geometric

  17. The Structure and Properties of Cast Iron Alloyed with Copper

    NASA Astrophysics Data System (ADS)

    Razumakov, A. A.; Stepanova, N. V.; Bataev, I. A.; Lenivtseva, O. G.; Riapolova, Iu Iu; Emurlaev, K. I.

    2016-04-01

    Cast iron with 3 wt. % Cu was prepared by induction melting and casting in sand molds. The structure of the samples was studied using light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The addition of Cu promoted formation of pearlite and slightiy decreased the volume fraction of graphite. No Cu inclusions were found by LM and SEM. The nanoprecipitations of ε-Cu in lamellar pearlite were observed by TEM. The properties of the Cu-alloyed cast iron were compared with the properties of cast iron not alloyed with Cu. The hardness of cast iron after alloying with Cu increased and the friction coefficient decreased in comparison with the reference sample.

  18. Complex foamed aluminum parts as permanent cores in aluminum castings

    SciTech Connect

    Simancik, F.; Schoerghuber, F.

    1998-12-31

    The feasibility of complex shaped aluminum foam parts as permanent cores in aluminum castings has been investigated. The foamed samples were prepared by injection of the foam into sand molds. It turned out that sound castings can be produced if the foam core is properly preheated and/or surface treated before casting. The effect of the foam core on the performance of the casting was evaluated by in compression testing and by measuring structural damping. The gain in the related properties turned out to be much higher than the weight increase of the casting due to the presence of the core. The weight increase may be partially offset through a reduction of the wall-thickness of the shell.

  19. Modeling of cast systems using smoothed-particle hydrodynamics

    NASA Astrophysics Data System (ADS)

    Cleary, Paul; Prakash, Mahesh; Ha, Joseph; Sinnott, Matthew; Nguyen, Thang; Grandfield, John

    2004-03-01

    To understand and control the filling process for metals in high-pressure die casting and ingot casting, researchers have used new flow-simulation software for the modeling of mold filling. Smoothed-particle hydrodynamics (SPH) is a non-conventional computational fluid dynamics method that has been successfully applied to these problems. Due to its mesh-free nature, it can handle complex splashing free surface flows and the differential motion of multiple solid-casting equipment components relatively easily. The ability of SPH to predict the detailed filling patterns of real large-scale automotive die castings is demonstrated in this study, and the use of SPH simulation for wheel shape optimization in ingot casting based on minimizing oxide generation while increasing the throughput is also presented.

  20. Development of low-temperature high-strength integral steel castings for offshore construction by casting process engineering

    NASA Astrophysics Data System (ADS)

    Lim, Sang-Sub; Mun, Jae-Chul; Kim, Tae-Won; Kang, Chung-Gil

    2014-12-01

    In casting steels for offshore construction, manufacturing integral casted structures to prevent fatigue cracks in the stress raisers is superior to using welded structures. Here, mold design and casting analysis were conducted for integral casting steel. The laminar flow of molten metal was analyzed and distributions of hot spots and porosities were studied. A prototype was subsequently produced, and air vents were designed to improve the surface defects caused by the release of gas. A radiographic test revealed no internal defects inside the casted steel. Evaluating the chemical and mechanical properties of specimens sampled from the product revealed that target values were quantitatively satisfied. To assess weldability in consideration of repair welding, the product was machined with grooves and welded, after which the mechanical properties of hardness as well as tensile, impact, and bending strengths were evaluated. No substantive differences were found in the mechanical properties before and after welding.

  1. Effect of flask vibration time on casting integrity, Surface Penetration and Coating Inclusion in lost foam casting of Al-Si Alloy

    SciTech Connect

    Karimian, Majid; Idris, M. H.; Ourdjini, A.; Muthu, Kali

    2011-01-17

    The paper presents the result of an experimental investigation conducted on medium aluminum silicon alloy casting- LM6, using no-vacuum assisted lost foam casting process. The study is directed for establishing the relationship between the flask vibrations times developed for molded sample on the casting integrity, surface penetration and coating inclusion defects of the casting. Four different flask vibration times namely 180, 120, 90 and 60 sec. were investigated. The casting integrity was investigated in terms of fulfilling in all portions and edges. The surface penetration was measured using optical microscope whilst image analyzer was used to quantify the percentage of coating inclusion in the casting. The results show that vibration time has significant influence on the fulfilling as well as the internal integrity of the lost foam casting. It was found that the lower vibration time produced comparatively sound casing.

  2. INJECTION-MOLDING APPARATUS

    DOEpatents

    Lobell, G.M.

    1958-02-11

    This patent is drawn to an injection molding apparatus for producing a tube closed at one end wherein the normally unsupported end of the core located in the cavity during the injection of the molten material to fill the space between the core and cavity wall, which supporting means is automatically removed from operation during the forming of the closed end of the tube. This support means is a plug extending through the end of the core into a recess in the bottom of the cavity where the closed end of the tube is to be formed. The plug is spring pressed into said recess and is forced out of the recess by a slidable bushing at the top of the cavity which is moved against the force of the spring by the molten material when it fills the uppormost open end portion of the cavity, thereby permitting the closed end of the tube to be formed.

  3. System and process for the abatement of casting pollution, reclaiming resin bonded sand, and/or recovering a low Btu fuel from castings

    DOEpatents

    Scheffer, K.D.

    1984-07-03

    Air is caused to flow through the resin bonded mold to aid combustion of the resin binder to form a low Btu gas fuel. Casting heat is recovered for use in a waste heat boiler or other heat abstraction equipment. Foundry air pollutis reduced, the burned portion of the molding sand is recovered for immediate reuse and savings in fuel and other energy is achieved. 5 figs.

  4. System and process for the abatement of casting pollution, reclaiming resin bonded sand, and/or recovering a low BTU fuel from castings

    DOEpatents

    Scheffer, Karl D.

    1984-07-03

    Air is caused to flow through the resin bonded mold to aid combustion of the resin binder to form a low BTU gas fuel. Casting heat is recovered for use in a waste heat boiler or other heat abstraction equipment. Foundry air pollution is reduced, the burned portion of the molding sand is recovered for immediate reuse and savings in fuel and other energy is achieved.

  5. Low Cost Al-Si Casting Alloy As In-Situ Composite for High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Lee, Jonathan A.

    2000-01-01

    A new aluminum-silicon (Al-Si) alloy has been successfully developed at NASA- Marshall Space Flight Center (MSFC) that has significant improvement in tensile and fatigue strength at elevated temperatures (500 F-700 F). The alloy offers a number of benefits such as light weight, high hardness, low thermal expansion and high surface wear resistance. In hypereutectic form, this alloy is considered as an in-situ Al-Si composite with tensile strength of about 90% higher than the auto industry 390 alloy at 600 F. This composite is very economically produced by using either conventional permanent steel molds or die casting. The projected material cost is less than $0.90 per pound, and automotive components such as pistons can be cast for high production rate using conventional casting techniques with a low and fully accounted cost. Key Words: Metal matrix composites, In-situ composite, aluminum-silicon alloy, hypereutectic alloy, permanent mold casting, die casting.

  6. Current status of mold immunotherapy.

    PubMed

    Dhillon, M

    1991-05-01

    There is evidence to suggest that molds can cause IgE-mediated upper respiratory tract disorders and immunotherapy is efficacious in a select group. The environmental sampling studies show a remarkably small numbers of molds accounting for a majority of the mold load in various diverse locations. These are Cladosporium, Basidiospores, Aspergillus, and Alternaria-Penicillin families. Basidiospores have been underreported in the older studies because of difficulties in their identification. Whether the absolute mold level is the most important factor leading to IgE formation and induction of upper respiratory tract symptoms is uncertain. Certainly, the majority of the studies are based on the assumption that the absolute level of mold in the environment is the most important factor leading to the development of symptoms, but this is not based on strong evidence. A major problem in the majority of the studies is a lack of standardization of extracts which may lead to false negatives on skin testing and thus produce variable data in population evaluations comparing the prevalence of mold to its ability to induce IgE production and symptoms. The best current trials to document the efficacy of mold immunotherapy have been with the standardized Cladosporium extract. Unfortunately, these results cannot be extrapolated to the commercially available mold extracts available in the United States either for immunotherapy or for skin testing. These extracts are highly variable in their potency, prone to high false negative rates, and at best serve as poor skin testing reagents and possibly even worse immunotherapy reagents. Adequately standardized mold reagents are urgently needed to determine whether the Cladosporium data can be extrapolated to them in any meaningful way. PMID:2035901

  7. Research in manufacturing of micro-structured injection molded polymer parts

    NASA Astrophysics Data System (ADS)

    Lucyshyn, Thomas; Struklec, Tobias; Burgsteiner, Martin; Graninger, Georg; Holzer, Clemens

    2015-12-01

    An overview of current research results is given for the topic of injection molding of micro-structured polymer parts regarding filling behavior and demolding process of micro-structures as well as the production of micro-structures on curved surfaces. In order to better understand how micro-structures are formed during the filling stage of injection molding, a study was performed on a test part with micro-channels placed parallely and perpendicularly to flow direction. Short shots with a highly fluent Polypropylene grade were injection molded with the melt front stopping in the structure fields. The melt and mold temperature, the injection rate as well as the use of a variotherm heating system were varied in a systematic Design of Experiments. The shape of the flow front was investigated with the optical measurement system Alicona InfiniteFocus. The data gained was analyzed with Matlab scripts and provided the needed distance to completely fill the structures as a reference value. The next topic covers the demolding step, which is a crucial process step in injection molding of micro-structured parts as the successfully replicated structures often get destroyed in the following demolding step. In order to evaluate the influence of the four aspects polymer, mold surface (coatings), structure (geometry and placement) and process settings on the demolding behavior, an injection mold with integrated measurement system was built, which makes it possible to measure the demolding force respectively a demolding energy under process conditions. These values can be used to quantitatively compare the impact of the above mentioned influencing factors on demolding. Finally, a concept to produce micro-structures on curved surfaces with injection molding is shown: A flat metal premaster structure is used to produce an elastomeric polymer (dimethylsiloxane) master in a casting process. This master is fixed in a conventional injection mold and a thermoplastic polymer is replicated

  8. Predicting Pattern Tooling and Casting Dimensions for Investment Casting, Phase III

    SciTech Connect

    Sabau, Adrian S

    2008-04-01

    Efforts during Phase III focused mainly on the shell-alloy systems. A high melting point alloy, 17-4PH stainless steel, was considered. The experimental part of the program was conducted at ORNL and commercial foundries, where wax patterns were injected, molds were invested, and alloys were poured. Shell molds made of fused-silica and alumino-silicates were considered. A literature review was conducted on thermophysical and thermomechanical properties alumino-silicates. Material property data, which were not available from material suppliers, was obtained. For all the properties of 17-4PH stainless steel, the experimental data available in the literature did not cover the entire temperature range necessary for process simulation. Thus, some material properties were evaluated using ProCAST, based on CompuTherm database. A comparison between the predicted material property data and measured property data was made. It was found that most material properties were accurately predicted only over several temperature ranges. No experimental data for plastic modulus were found. Thus, several assumptions were made and ProCAST recommendations were followed in order to obtain a complete set of mechanical property data at high temperatures. Thermal expansion measurements for the 17-4PH alloy were conducted during heating and cooling. As a function of temperature, the thermal expansion for both the alloy and shell mold materials showed different evolution on heating and cooling. Numerical simulations were performed using ProCAST for the investment casting of 17-4PH stainless steel parts in fused silica molds using the thermal expansion obtained on heating and another one with thermal expansion obtained on cooling. Since the fused silica shells had the lowest thermal expansion properties in the industry, the dewaxing phase, including the coupling between wax-shell systems, was neglected. The shell mold was considered to be a pure elastic material. The alloy dimensions were

  9. Ceramic injection molding material analysis, modeling and injection molding simulation

    NASA Astrophysics Data System (ADS)

    Drummer, D.; Messingschlager, S.

    2014-05-01

    In comparison to unfilled polymers, a ceramic feedstocks has a very high viscosity, a very high heat conductivity and a different pvT-behavior. So far standard simulation tools for plastic injection molding are capable of simulating unfilled or fiber filled compounds with their typical low viscosity and heat conductivity etc. but not for very high ceramic powder filled polymers. This article shows an approach of preparing and adding ceramic feedstocks to standard injection molding tools. Two different feedstocks are used.

  10. Transfer molding of PMR-15 polyimide resin

    NASA Technical Reports Server (NTRS)

    Reardon, J. P.; Moyer, D. W.; Nowak, B. E.

    1985-01-01

    Transfer molding is an economically viable method of producing small shapes of PMR-15 polyimide. It is shown that with regard to flexural, compressive, and tribological properties transfer-molded PMR-15 polyimide is essentially equivalent to PMR-15 polyimide produced by the more common method of compression molding. Minor variations in anisotropy are predictable effects of molding design and secondary finishing operations.

  11. ILLUSTRATED HANDBOOK OF SOME COMMON MOLDS.

    ERIC Educational Resources Information Center

    CHANDLER, MARION N.

    THIS DOCUMENT IS A PICTURE GUIDE FOR THE IDENTIFICATION OF TEN COMMON MOLDS. IT IS DESIGNED FOR USE WITH THE ELEMENTARY SCIENCE STUDY UNIT "MICROGARDENING" AND IS SUGGESTED FOR UPPER ELEMENTARY GRADES. INCLUDED FOR EACH MOLD ARE COLOR PHOTOGRAPHS AND PHOTOMICROGRAPHS OF THE INTACT MOLD MASS AND OF THE MOLD'S SPORE PRODUCING STRUCTURES. ALSO…

  12. Rapid control of mold temperature during injection molding process

    NASA Astrophysics Data System (ADS)

    Liparoti, Sara; Hunag, Tsang Min; Sorrentino, Andrea; Titomanlio, Giuseppe; Cakmak, Mukerrem

    2015-05-01

    The control of mold surface temperature is an important factor that determines surface morphology and its dimension in thickness direction. It can also affect the frozen molecular orientation and the mold surface replicability in injection molded products. In this work, thin thermally active films were used to quickly control the mold surface temperature. In particular, an active high electrical conductivity carbon black loaded polyimide composites sandwiched between two insulating thin polymeric layers was used to condition the mold surface. By controlling the heating time, it was possible to control precisely the temporal variation of the mold temperature surface during the entire cycle. The surface heating rate was about 40°C/s and upon contact with the polymer the surface temperature decreased back to 40°C within about 5 s; the overall cycle time increased only slightly. The effect on cross section sample morphology of samples of iPP were analyzed and discussed on the basis of the recorded temperature evolution.

  13. Rapid control of mold temperature during injection molding process

    SciTech Connect

    Liparoti, Sara; Titomanlio, Giuseppe; Hunag, Tsang Min; Cakmak, Mukerrem; Sorrentino, Andrea

    2015-05-22

    The control of mold surface temperature is an important factor that determines surface morphology and its dimension in thickness direction. It can also affect the frozen molecular orientation and the mold surface replicability in injection molded products. In this work, thin thermally active films were used to quickly control the mold surface temperature. In particular, an active high electrical conductivity carbon black loaded polyimide composites sandwiched between two insulating thin polymeric layers was used to condition the mold surface. By controlling the heating time, it was possible to control precisely the temporal variation of the mold temperature surface during the entire cycle. The surface heating rate was about 40°C/s and upon contact with the polymer the surface temperature decreased back to 40°C within about 5 s; the overall cycle time increased only slightly. The effect on cross section sample morphology of samples of iPP were analyzed and discussed on the basis of the recorded temperature evolution.

  14. Predicting Pattern Tooling and Casting Dimensions for Investment Casting, Phase II

    SciTech Connect

    Nick Cannell; Adrian S. Sabau

    2005-09-30

    The investment casting process allows the production of complex-shape parts and close dimensional tolerances. One of the most important phases in the investment casting process is the design of the pattern die. Pattern dies are used to create wax patterns by injecting wax into dies. The first part of the project involved preparation of reports on the state of the art at that time for all the areas under consideration (die-wax, wax-shell, and shell-alloy). The primary R&D focus during Phase I was on the wax material since the least was known about it. The main R&D accomplishments during this phase were determination of procedures for obtaining the thermal conductivity and viscoelastic properties of an unfilled wax and validating those procedures. Phase II focused on die-wax and shell-alloy systems. A wax material model was developed based on results obtained during the previous R&D phase, and a die-wax model was successfully incorporated into and used in commercial computer programs. Current computer simulation programs have complementary features. A viscoelastic module was available in ABAQUS but unavailable in ProCAST, while the mold-filling module was available in ProCAST but unavailable in ABAQUS. Thus, the numerical simulation results were only in good qualitative agreement with experimental results, the predicted shrinkage factors being approximately 2.5 times larger than those measured. Significant progress was made, and results showed that the testing and modeling of wax material had great potential for industrial applications. Additional R&D focus was placed on one shell-alloy system. The fused-silica shell mold and A356 aluminum alloy were considered. The experimental part of the program was conducted at ORNL and commercial foundries, where wax patterns were injected, molds were invested, and alloys were poured. It was very important to obtain accurate temperature data from actual castings, and significant effort was made to obtain temperature profiles in

  15. Comparison of interfacial heat transfer coefficient estimated by two different techniques during solidification of cylindrical aluminum alloy casting

    NASA Astrophysics Data System (ADS)

    Rajaraman, R.; Velraj, R.

    2008-07-01

    The interfacial heat transfer coefficient (IHTC) is necessary for accurate simulation of the casting process. In this study, a cylindrical geometry is selected for the determination of the IHTC between aluminum alloy casting and the surrounding sand mold. The mold surface heat flux and temperature are estimated by two inverse heat conduction techniques, namely Beck’s algorithm and control volume technique. The instantaneous cast and mold temperatures are measured experimentally and these values are used in the theoretical investigations. In the control volume technique, partial differential heat conduction equation is reduced to ordinary differential equations in time, which are then solved sequentially. In Beck’s method, solution algorithm is developed under the function specification method to solve the inverse heat conduction equations. The IHTC was determined from the surface heat flux and the mold surface temperature by both the techniques and the results are compared.

  16. White mold of Jerusalem artichoke

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Jerusalem artichoke (Helianthus tuberosus) is a Native American food plant closely related to the common sunflower (Helianthus annuus). Tubers of Jerusalem artichoke are increasingly available in retail grocery outlets. White mold (Sclerotinia stem rot), caused by the fungus, Sclerotinia sclerotioru...

  17. A Study for Initial Solidification of Sn-Pb Alloy During Continuous Casting: Part II. Effects of Casting Parameters on Initial Solidification and Shell Surface

    NASA Astrophysics Data System (ADS)

    Zhou, Dong; Wang, Wanlin; Zhang, Haihui; Ma, Fanjun; Chen, Ken; Zhou, Lejun

    2014-06-01

    The initial shell solidification of liquid steel in the mold has significant influence on both surface and internal quality of the final slab, and it is mainly determined by the high transient high temperature thermodynamics occurring in the mold. This study investigated the effects of casting parameters like casting temperature, mold oscillation frequency, and stroke on the initial solidification of a Sn-Pb alloy through the use of a mold simulator to allow the clear understanding of the inter-relationship between irregular shell solidification, heat transfer, negative strip time (NST), and casting conditions. Results suggested that the shell surface oscillation marks (OMs) are strongly depending upon the fluctuations of meniscus responding temperatures and heat flux. An abrupt sudden fluctuation of high frequency temperature and heat flux at the meniscus during the NST would deteriorate the shell surface and leads to deep OMs. The fluctuations of responding temperature and heat flux are determined by the NST, meniscus solidification, and oil infiltration, which in turn are influenced by casting conditions, like casting temperature, oscillation frequency, stroke, etc.

  18. Molded polymer solar water heater

    DOEpatents

    Bourne, Richard C.; Lee, Brian E.

    2004-11-09

    A solar water heater has a rotationally-molded water box and a glazing subassembly disposed over the water box that enhances solar gain and provides an insulating air space between the outside environment and the water box. When used with a pressurized water system, an internal heat exchanger is integrally molded within the water box. Mounting and connection hardware is included to provide a rapid and secure method of installation.

  19. Numerical simulation and fabrication of silicon sheet via spin casting.

    PubMed

    Lee, Jaewoo; Kim, Hyunhui; Lee, Changbum; Kim, Joonsoo; Jang, Bo-Yun; Lee, Jinseok; Ahn, Youngsoo; Yoon, Wooyoung

    2013-05-01

    A spin-casting process for fabricating polycrystalline silicon sheets for use as solar cell wafers is proposed, and the parameters that control the sheet thickness are investigated. A numerical study of the fluidity of molten silicon indicates that the formation of thin silicon sheets without a mold and via spin casting is feasible. The faster the rotation speed of graphite mold, the thinner the thickness of sheet. After the spread of the molten silicon to cover the graphite mold with rotation speed of above 500 rpm, the solidification has to start. Silicon sheets can be produced by using the centrifugal force under appropriate experimental conditions. The spin-cast sheet had a vertical columnar microstructure due to the normal heat extraction to the substrate, and the sheet lifetime varied from 0.1 microS to 0.3 microS measured by using the microwave photoconductance decay (MW-PCD) to confirm that the spin-cast silicon sheet is applicable to photovoltaics. PMID:23858887

  20. Development of dental casting and porcelainizing techniques for titanium alloys

    SciTech Connect

    Taira, M.

    1986-01-01

    Casting of titanium metals has been difficult due to their high chemical reactivity at elevated temperatures. Thus, special melting and mold materials are needed. This study investigated molds, Ti alloys, and porcelain applications, utilizing a new dental casting machine, Castmatic. It involved argon-arc melting and subsequent argon/vacuum pressurized casting. Special refractory oxides such as yttria or Zirconia A were utilized for a face coat under phosphate bonded silica investment. Studies of Ti alloys (Ti, Ti-6Al-4V, Ti-15V, Ti-20Cu and Ti-30Pd) involved metallography, phase identification (XRD), hardness, tensile tests, and electrochemical-corrosion tests. Preliminary porcelain studies included an experimental low fusing porcelain along with commercial low fusing porcelains. The bond was evaluated by three-point bending tests and SEM/EDX observations. The yttria face coat was inert, but lacked the necessary mechanical and thermal stability. The face coat, consisting of Zirconia A and zirconium acetate binder, was stable and resulted in less mold reactivity, good internal soundness, but slightly rough surfaces. Metallographs revealed quite larger grains in the cast structure, than in the wrought forms. XRD analysis showed that quasi-equilibrium phases present.

  1. Materials for Advanced Ultrasupercritical Steam Turbines Task 4: Cast Superalloy Development

    SciTech Connect

    Thangirala, Mani

    2015-09-30

    demonstrated the importance of proper heat treat cycles for Homogenization, and Solutionizing parameters selection and implementation. 3) Step blocks casting of Nimonic 263: Carried out casting solidification simulation analysis, NDT inspection methods evaluation, detailed test matrix for Chemical, Tensile, LCF, stress rupture, CVN impact, hardness and J1C Fracture toughness section sensitivity data and were reported. 4) Centrifugal Casting of Haynes 282, weighing 1400 lbs. with hybrid mold (half Graphite and half Chromite sand) mold assembly was cast using compressor casing production tooling. This test provided Mold cooling rates influence on centrifugally cast microstructure and mechanical properties. Graphite mold section out performs sand mold across all temperatures for 0.2% YS; %Elongation, %RA, UTS at 1400°F. Both Stress-LMP and conditional Fracture toughness plots data were in the scatter band of the wrought alloy. 5) Fundamental Studies on Cooling rates and SDAS test program. Evaluated the influence of 6 mold materials Silica, Chromite, Alumina, Silica with Indirect Chills, Zircon and Graphite on casting solidification cooling rates. Actual Casting cooling rates through Liquidus to Solidus phase transition were measured with 3 different locations based thermocouples placed in each mold. Compared with solidification simulation cooling rates and measurement of SDAS, microstructure features were reported. The test results provided engineered casting potential methods, applicable for heavy section Haynes 282 castings for optimal properties, with foundry process methods and tools. 6) Large casting of Haynes 282 Drawings and Engineering FEM models and supplemental requirements with applicable specifications were provided to suppliers for the steam turbine proto type feature valve casing casting. Molding, melting and casting pouring completed per approved Manufacturing Process Plan during 2014 Q4. The partial valve casing was successfully cast after casting methods were

  2. Effect of Water Vapor on Evaporation and Melt Crystallization of Mold Fluxes

    NASA Astrophysics Data System (ADS)

    Baek, Ji-Yeon; Cho, Jung-Wook; Kim, Seon-Hyo

    2016-02-01

    Melt crystallization behavior of both the fluorine-containing and fluorine-free mold fluxes has been investigated using a single hot thermocouple technique (SHTT). By increasing the dew point of atmosphere from 223 K to 285.5 K (-50 °C and 12.5 °C), the primary crystalline phase of fluorine-containing mold flux was changed from cuspidine (Ca4Si2O7F2) to Ca2SiO4 with accelerated nucleation rates. Enhancement of fluorine evaporation due to hydroxyl is attributed to the main reason for the abnormal crystallization behavior of the fluorine-containing mold flux under humid atmosphere, which may bring a sticking-type breakout during the commercial continuous casting process. In contrast, the effect of water vapor on crystallization of fluorine-free mold flux was negligible. This implies that the application of fluorine-free mold fluxes can become a countermeasure to prevent the hydrogen-induced breakout during the continuous casting process under wet atmosphere.

  3. Deep UV patterning of acrylic masters for molding biomimetic dry adhesives

    NASA Astrophysics Data System (ADS)

    Sameoto, D.; Menon, C.

    2010-11-01

    We present a novel fabrication method for the production of biomimetic dry adhesives that allows enormous variation in fiber shapes and sizes. The technology is based on deep-UV patterning of commercial acrylic with semi-collimated light available from germicidal lamps, and combined careful processing conditions, material selection and novel developer choices to produce relatively high-aspect-ratio fibers with overhanging caps on large areas. These acrylic fibers are used as a master mold for subsequent silicone rubber negative mold casting. Because the bulk acrylic demonstrates little inherent adhesion to silicone rubbers, the master molds created in this process do not require any surface treatments to achieve high-yield demolding of interlocked structures. Multiple polymers can be cast from silicone rubber negative molds and this process could be used to structure smart materials on areas over multiple square feet. Using direct photopatterning of acrylic allows many of the desired structures for biomimetic dry adhesives to be produced with relative ease compared to silicon-based molding processes, including angled fibers and hierarchical structures. Optimized fiber shapes for a variety of polymers can be produced using this process, and adhesion measurements on a well-characterized polyurethane, ST-1060, are used to determine the effect of fiber geometry on adhesion performance.

  4. Rapid prototyping of biodegradable microneedle arrays by integrating CO2 laser processing and polymer molding

    NASA Astrophysics Data System (ADS)

    Tu, K. T.; Chung, C. K.

    2016-06-01

    An integrated technology of CO2 laser processing and polymer molding has been demonstrated for the rapid prototyping of biodegradable poly-lactic-co-glycolic acid (PLGA) microneedle arrays. Rapid and low-cost CO2 laser processing was used for the fabrication of a high-aspect-ratio microneedle master mold instead of conventional time-consuming and expensive photolithography and etching processes. It is crucial to use flexible polydimethylsiloxane (PDMS) to detach PLGA. However, the direct CO2 laser-ablated PDMS could generate poor surfaces with bulges, scorches, re-solidification and shrinkage. Here, we have combined the polymethyl methacrylate (PMMA) ablation and two-step PDMS casting process to form a PDMS female microneedle mold to eliminate the problem of direct ablation. A self-assembled monolayer polyethylene glycol was coated to prevent stiction between the two PDMS layers during the peeling-off step in the PDMS-to-PDMS replication. Then the PLGA microneedle array was successfully released by bending the second-cast PDMS mold with flexibility and hydrophobic property. The depth of the polymer microneedles can range from hundreds of micrometers to millimeters. It is linked to the PMMA pattern profile and can be adjusted by CO2 laser power and scanning speed. The proposed integration process is maskless, simple and low-cost for rapid prototyping with a reusable mold.

  5. A Study of the Oscillation Marks' Characteristics of Continuously Cast Incoloy Alloy 825 Blooms

    NASA Astrophysics Data System (ADS)

    Saleem, Saud; Vynnycky, Michael; Fredriksson, Hasse

    2016-06-01

    A comprehensive experimental study of oscillation mark (OM) formation and its characteristics during the solidification of Incoloy alloy 825 in the continuous casting of blooms is investigated by plant trials and metallographic study. The experiments involved two heats with the same casting and mold conditions and sampling at different locations across the strand. The metallographic study combined macro/micro-examinations of OMs and segregation analysis of Cr, Mn, Mo, Ni, and Si by microprobe analysis. The results show that OMs have widely different characteristics, such as mark type, depth, segregation, and accompanying microstructure. Furthermore, the mark pitch can vary considerably even for the similar casting conditions, leading to different conditions for the marks' formation in relation to the mold's cyclic movement. Finally, a mechanism for the OM formation is discussed and proposed. Possible solutions for minimizing the observed defects by optimizing the mold conditions are suggested.

  6. A Study of the Oscillation Marks' Characteristics of Continuously Cast Incoloy Alloy 825 Blooms

    NASA Astrophysics Data System (ADS)

    Saleem, Saud; Vynnycky, Michael; Fredriksson, Hasse

    2016-08-01

    A comprehensive experimental study of oscillation mark (OM) formation and its characteristics during the solidification of Incoloy alloy 825 in the continuous casting of blooms is investigated by plant trials and metallographic study. The experiments involved two heats with the same casting and mold conditions and sampling at different locations across the strand. The metallographic study combined macro/micro-examinations of OMs and segregation analysis of Cr, Mn, Mo, Ni, and Si by microprobe analysis. The results show that OMs have widely different characteristics, such as mark type, depth, segregation, and accompanying microstructure. Furthermore, the mark pitch can vary considerably even for the similar casting conditions, leading to different conditions for the marks' formation in relation to the mold's cyclic movement. Finally, a mechanism for the OM formation is discussed and proposed. Possible solutions for minimizing the observed defects by optimizing the mold conditions are suggested.

  7. Deposition of ultrafine aerosols in rat nasal molds

    SciTech Connect

    Cheng, Y.S.; Hansen, G.K.; Su, Y.F.; Yeh, H.C. ); Morgan, K.T. )

    1990-01-01

    To evaluate the health effect of air pollutants on the respiratory tract, it is critical to determine the regional deposition of inhaled aerosols. Information on deposition of larger particles in the nasal passages of laboratory animals is available; the deposition fraction increases with increasing particle size. However, little deposition information is available for ultrafine particles of less than 0.2 {mu}m. Three clear, plastic molds (models) of the nasal passages of F344/N rats, prepared from metal replica casts used in these studies. Total deposition of ultrafine aerosols in the casts was determined by using a unidirectional flow system. The pressure drops measured in the casts were a function of flow rate to the power of 1.4-1.6, indicating that flow through the nasal passages has nonlaminar components. Deposition data were obtained by using monodisperse sodium chloride aerosols with particle sizes ranging from 0.2 to 0.005 {mu}m, at inspiratory and expiratory flow rates of 200 to 600 ml/min. Similar deposition data were obtained for two of the casts studied. Deposition efficiency was greatest for the smallest particles, and decreased with increasing particle size and flow rate. At an inspiratory flow rate of 400 ml/min, which is comparable to the mean respiratory flow of an adult male F344 rat with a respiratory minute volume of 200 ml, deposition efficiencies reached 40 and 70% for 0.01- and 0.005-{mu}m particles, respectively.

  8. Real-time video monitoring of ingot casting

    SciTech Connect

    Richter, R.T.; Adomaitis, P.R.; Hildeman, G.J.

    1996-10-01

    During start-up and steady-state casting of ingots, a number of effects related to ingot casting variables can be observed on the surface of the ingot. For example, the amount of curl at the bottom of the ingot, surface laps, liquation, cracks, and folds, as well as extreme events such as bleed-outs when molten metal melts through the shell of the ingot crater, are significant events which could be viewed. Unfortunately, observation of these surface effects is difficult since the as-cast surface is hidden below the casting table and direct visual observations of ingot surfaces are limited due to the proximity of the molds, cooling water sprays, and the ability of the casting operators to safely view ingot surface details at close range. The purpose of this paper is to describe a unique video monitoring capability which is being used as Alcoa`s Advanced Vertical Casting facility, to observe in real-time, surface effects of an ingot during casting. A description of the development of the video monitoring system, including camera, lighting, and video recording capability will be presented. Examples of various surface conditions on direct chill (DC) and electromagnetic cast (EMC) ingots will also be discussed.

  9. Rapid Tooling via Investment Casting and Rapid Prototype Patterns

    SciTech Connect

    Baldwin, Michael D.

    1999-06-01

    The objective of this work to develop the materials processing and design technologies required to reduce the die development time for metal mold processes from 12 months to 3 months, using die casting of Al and Mg as the example process. Sandia demonstrated that investment casting, using rapid prototype patterns produced from Stereo lithography or Selective laser Sintering, was a viable alternative/supplement to the current technology of machining form wrought stock. A demonstration die insert (ejector halt) was investment cast and subsequently tested in the die casting environment. The stationary half of the die insert was machined from wrought material to benchmark the cast half. The two inserts were run in a die casting machine for 3,100 shots of aluminum and at the end of the run no visible difference could be detected between the cast and machined inserts. Inspection concluded that the cast insert performed identically to the machined insert. Both inserts had no indications of heat checking or degradation.

  10. Bifilm Defects in Ni-Based Alloy Castings

    NASA Astrophysics Data System (ADS)

    Campbell, John; Tiryakioğlu, Murat

    2012-08-01

    The Ni-base superalloys, which are normally melted and cast in a vacuum, entrain their surface-oxide film during turbulent pouring of the melt; unfortunately at this time, this process is universally practiced for investment castings of these materials. The entrained film becomes a bifilm crack automatically, so that cast alloys have a large population of cracks that controls their failure behavior. The problems of the growth of single crystals and the welding of polycrystalline alloys are reviewed to illustrate the central role of bifilms in the cracking of turbine blades, the heat-affected zones of welds, and the reliability of properties. It has been demonstrated that improved gravity pouring systems can reduce these problems significantly, but only countergravity filling of molds is expected to result in defect-free castings. Recent cases in which turbine blades failed in service are examined, and the central role of bifilm defects in these failures is discussed.

  11. Casting Simulation of an Austrian Bronze Age Sword Hilt

    NASA Astrophysics Data System (ADS)

    Pola, Annalisa; Mödlinger, Marianne; Piccardo, Paolo; Montesano, Lorenzo

    2015-07-01

    Bronze Age swords with a metal hilt can be considered the peak of Bronze Age casting technologies. To reconstruct the casting techniques used more than 3000 years ago, a metal hilted sword of the Schalenknauf type from Lower Austria was studied with the aid of macroscopic analyses and simulation of mold filling and casting solidification. A three-dimensional model of the hilt was created based on optical scanner measurements performed on a hilt recently discovered during archaeological excavations. Three different configurations of the gating system were considered, two on the pommel disk and one on the knob, and the effect of its location on the formation of casting defects was investigated. Three-dimensional computed tomography was used to detect internal defects, such as gas and shrinkage porosity, which were then compared with those calculated by simulation. The best match between actual and predicted hilt quality demonstrated the location of the gating system, which turned out to be on the pommel disk.

  12. Electromagnetic augmentation for casting of thin metal sheets

    DOEpatents

    Hull, John R.

    1989-01-01

    Thin metal sheets are cast by magnetically levitating molten metal deposited in a mold within a ferromagnetic yoke and between AC conducting coils and linearly displacing the magnetically levitated liquid metal while it is being cooled by the water-cooled walls of the mold to form a solid metal sheet. A conducting shield is electrically coupled to the molten metal sheet to provide a return path for eddy currents induced in the metal sheet by the current in the AC conducting coils. In another embodiment, a DC conducting coil is coupled to the metal sheet for providing a direct current therein which interacts with the magnetic field to levitate the moving metal sheet. Levitation of the metal sheet in both molten and solid forms reduces its contact pressure with the mold walls while maintaining sufficient engagement therebetween to permit efficient conductive cooling by the mold through which a coolant fluid may be circulated. The magnetic fields associated with the currents in the aforementioned coils levitate the molten metal sheet while the mold provides for its lateral and vertical confinement. A leader sheet having electromagnetic characteristics similar to those of the molten metal sheet is used to start the casing process and precedes the molten metal sheet through the yoke/coil arrangement and mold and forms a continuous sheet therewith. The yoke/coil arrangement may be either U-shaped with a single racetrack coil or may be rectangular with a pair of spaced, facing bedstead coils.

  13. Rotationally Molded Liquid Crystalline Polymers

    NASA Technical Reports Server (NTRS)

    Rogers, Martin; Stevenson, Paige; Scribben, Eric; Baird, Donald; Hulcher, Bruce

    2002-01-01

    Rotational molding is a unique process for producing hollow plastic parts. Rotational molding offers advantages of low cost tooling and can produce very large parts with complicated shapes. Products made by rotational molding include water tanks with capacities up to 20,000 gallons, truck bed liners, playground equipment, air ducts, Nylon fuel tanks, pipes, toys, stretchers, kayaks, pallets, and many others. Thermotropic liquid crystalline polymers are an important class of engineering resins employed in a wide variety of applications. Thermotropic liquid crystalline polymers resins are composed of semi-rigid, nearly linear polymeric chains resulting in an ordered mesomorphic phase between the crystalline solid and the isotropic liquid. Ordering of the rigid rod-like polymers in the melt phase yields microfibrous, self-reinforcing polymer structures with outstanding mechanical and thermal properties. Rotational molding of liquid crystalline polymer resins results in high strength and high temperature hollow structures useful in a variety of applications. Various fillers and reinforcements can potentially be added to improve properties of the hollow structures. This paper focuses on the process and properties of rotationally molded liquid crystalline polymers.

  14. Rotationally Molded Liquid Crystalline Polymers

    NASA Technical Reports Server (NTRS)

    Rogers, Martin; Scribben, Eric; Baird, Donald; Hulcher, Bruce

    2002-01-01

    Rotational molding is a unique process for producing hollow plastic parts. Rotational molding offers low cost tooling and can produce very large parts with complicated shapes. Products made by rotational molding include water tanks with capacities up to 20,000 gallons, truck bed liners, playground equipment, air ducts, Nylon fuel tanks, pipes, toys, stretchers, kayaks, pallets, and many others. Thermotropic liquid crystalline polymers are an important class of engineering resins employed in a wide variety of applications. Thermotropic liquid crystalline polymers resins are composed of semirigid, nearly linear polymeric chains resulting in an ordered mesomorphic phase between the crystalline solid and the isotropic liquid. Ordering of the rigid rod-like polymers in the melt phase yields microfibrous, self-reinforcing polymer structures with outstanding mechanical and thermal properties. Rotational molding of liquid crystalline polymer resins results in high strength and high temperature hollow structures useful in a variety of applications. Various fillers and reinforcements can potentially be added to improve properties of the hollow structures. This paper focuses on the process and properties of rotationally molded liquid crystalline polymers. This paper will also highlight the interactions between academia and small businesses in developing new products and processes.

  15. Twin-belt continuous caster with containment and cooling of the exiting cast product for enabling high-speed casting of molten-center product

    DOEpatents

    Dykes, Charles D.; Daniel, Sabah S.; Wood, J. F. Barry

    1990-02-20

    In continuously casting molten metal into cast product by a twin-belt machine, it is desirable to achieve dramatic increases in speed (linear feet per minute) at which cast product exits the machine, particularly in installations where steel cast product is intended to feed a downstream regular rolling mill (as distinct from a planetary mill) operating in tandem with the twin-belt caster. Such high-speed casting produces product with a relatively thin shell and molten interior, and the shell tends to bulge outwardly due to metallostatic head pressure of the molten center. A number of cooperative features enable high-speed, twin-belt casting: (1) Each casting belt is slidably supported adjacent to the caster exit pulley for bulge control and enhanced cooling of cast product. (2) Lateral skew steering of each belt provides an effective increase in moving mold length plus a continuity of heat transfer not obtained with prior art belt steering apparatus. (3) The exiting slab is contained and supported downstream from the casting machine to prevent bulging of the shell of the cast product, and (4) spray cooling is incorporated in the exit containment apparatus for secondary cooling of cast product.

  16. Large structural, thin-wall castings made of metals subject to hot tearing, and their fabrication

    NASA Technical Reports Server (NTRS)

    Smashey, Russell W. (Inventor)

    2001-01-01

    An article, such as a gas turbine engine mixer, is made by providing a mold structure defining a thin-walled, hollow article, and a base metal that is subject to hot tear cracking when cast in a generally equiaxed polycrystalline form, such as Rene' 108 and Mar-M247. The article is fabricated by introducing the molten base metal into the mold structure, and directionally solidifying the base metal in the mold structure to form a directionally oriented structure. The directionally oriented structure may be formed of a single grain or oriented multiple grains.

  17. Initial solidification phenomena: Factors affecting heat transfer in strip casting

    NASA Astrophysics Data System (ADS)

    Nolli, Paolo

    In the last few years a few companies have announced the final stage of the commercial development of strip casting of steels. In strip casting heat extraction and productivity are limited by the thermal resistance at the interface between processed material and moving mold (rolls for twin-roll strip casters). Among many factors influencing interfacial heat transfer, films of various composition, either formed during casting or deposited before casting on the surface of the rolls, melt superheat and gas atmosphere composition can have a significantly positive or negative effect on the achieved heat transfer rate. From an industrial point view, methods to improve interfacial heat transfer rates must be found, in order to increase productivity. The objective of this research project is to assess if it is feasible to improve heat transfer rates during solidification of steel in direct contact with a copper mold: (1) by the application of thin coatings on the mold surface; (2) by adding a reactive gas species containing sulfur in the gas shrouding where casting is performed. To address the former, solidification experiments were performed with the mold surface either kept uncoated or coated with coatings of different compositions. To address the latter, the experiments were performed in gas shrouding atmospheres with or without sulphydric acid. It was observed that the resulting heat extraction rates were improved by the application of certain coatings and by the addition of H2S to the gas atmosphere. These findings prove that the application of coatings and the use of small amounts of reactive gaseous species containing sulfur may be methods to increase productivity in strip casting. The effect of superheat and the effect of naturally deposited oxides (Mn-oxide) were also evaluated experimentally. A numerical study of the effect of the critical undercooling on the productivity of a twin-roll strip caster showed that the maximum allowable casting speed can be increased

  18. Experimental study of glass molding process and transcription characteristics of mold surface in molding of aspheric glass lenses

    NASA Astrophysics Data System (ADS)

    Cha, Du Hwan; Park, Heung Su; Hwang, Yeon; Kim, Jeong-Ho; Kim, Hye-Jeong

    2011-03-01

    The effects of the process parameters in the molding of aspheric glass lenses for camera phone modules have been investigated experimentally and the surface topographies of the mold and the molded lens were compared to ascertain the transcription characteristics. The molding conditions were optimized with respect to the form error (PV) (the response variable) of the molded lens. The experimental conditions were obtained by employing a factorial design method. From the analysis of variance (ANOVA) and P-value (significance level), the slow cooling rate was found to affect the response variable most significantly. For the form topography, the lens molded under the optimum molding condition showed a transcription ratio of 93.4% against the mold.

  19. Flow behavior in liquid molding

    NASA Technical Reports Server (NTRS)

    Hunston, D.; Phelan, F.; Parnas, R.

    1992-01-01

    The liquid molding (LM) process for manufacturing polymer composites with structural properties has the potential to significantly lower fabrication costs and increase production rates. LM includes both resin transfer molding and structural reaction injection molding. To achieve this potential, however, the underlying science base must be improved to facilitate effective process optimization and implementation of on-line process control. The National Institute of Standards and Technology (NIST) has a major program in LM that includes materials characterization, process simulation models, on-line process monitoring and control, and the fabrication of test specimens. The results of this program are applied to real parts through cooperative projects with industry. The key feature in the effort is a comprehensive and integrated approach to the processing science aspects of LM. This paper briefly outlines the NIST program and uses several examples to illustrate the work.

  20. Staged mold for encapsulating hazardous wastes

    DOEpatents

    Unger, Samuel L.; Telles, Rodney W.; Lubowitz, Hyman R.

    1988-01-01

    A staged mold for stabilizing hazardous wastes for final disposal by molding an agglomerate of the hazardous wastes and encapsulating the agglomerate. Three stages are employed in the process. In the first stage, a first mold body is positioned on a first mold base, a mixture of the hazardous wastes and a thermosetting plastic is loaded into the mold, the mixture is mechanically compressed, heat is applied to cure the mixture to form a rigid agglomerate, and the first mold body is removed leaving the agglomerate sitting on the first mold base. In the second stage, a clamshell second mold body is positioned around the agglomerate and the first mold base, a powdered thermoplastic resin is poured on top of the agglomerate and in the gap between the sides of the agglomerate and the second mold body, the thermoplastic is compressed, heat is applied to melt the thermoplastic, and the plastic is cooled jacketing the agglomerate on the top and sides. In the third stage, the mold with the jacketed agglomerate is inverted, the first mold base is removed exposing the former bottom of the agglomerate, powdered thermoplastic is poured over the former bottom, the first mold base is replaced to compress the thermoplastic, heat is applied to melt the new thermoplastic and the top part of the jacket on the sides, the plastic is cooled jacketing the bottom and fusing with the jacketing on the sides to complete the seamless encapsulation of the agglomerate.

  1. Staged mold for encapsulating hazardous wastes

    DOEpatents

    Unger, Samuel L.; Telles, Rodney W.; Lubowitz, Hyman R.

    1990-01-01

    A staged mold for stabilizing hazardous wastes for final disposal by molding an agglomerate of the hazardous wastes and encapsulating the agglomerate. Three stages are employed in the process. In the first stage, a first mold body is positioned on a first mold base, a mixture of the hazardous wastes and a thermosetting plastic is loaded into the mold, the mixture is mechanically compressed, heat is applied to cure the mixture to form a rigid agglomerate, and the first mold body is removed leaving the agglomerate sitting on the first mold base. In the second stage, a clamshell second mold body is positioned around the agglomerate and the first mold base, a powdered thermoplastic resin is poured on top of the agglomerate and in the gap between the sides of the agglomerate and the second mold body, the thermoplastic is compressed, heat is applied to melt the thermoplastic, and the plastic is cooled jacketing the agglomerate on the top and sides. In the third stage, the mold with the jacketed agglomerate is inverted, the first mold base is removed exposing the former bottom of the agglomerate, powdered thermoplastic is poured over the former bottom, the first mold base is replaced to compress the thermoplastic, heat is applied to melt the new thermoplastic and the top part of the jacket on the sides, the plastic is cooled jacketing the bottom and fusing with the jacketing on the sides to complete the seamless encapsulation of the agglomerate.

  2. Cool Cast Facts

    MedlinePlus

    ... outer layer is usually made of plaster or fiberglass. Fiberglass casts are made of fiberglass, which is a plastic that can be shaped. Fiberglass casts come in many different colors — if you' ...

  3. Fabrication of Hierarchically Micro- and Nano-structured Mold Surfaces Using Laser Ablation for Mass Production of Superhydrophobic Surfaces

    NASA Astrophysics Data System (ADS)

    Noh, Jiwhan; Lee, Jae-Hoon; Na, Suckjoo; Lim, Hyuneui; Jung, Dae-Hwan

    2010-10-01

    Many studies have examined the formation of surfaces with mixed patterns of micro- and nano-sized lotus leaves that have hydrophobic properties. In this study, micro- and nano-shapes such as lotus leaves were fabricated on a metal mold surface using laser ablation and ripple formation. A microstructure on the mold surface was replicated onto poly(dimethylsiloxane) (PDMS) using the polymer casting method to manufacture low-cost hydrophobic surfaces. A PDMS surface with micro- and nano-structures that were the inverse image of a lotus leaf showed hydrophobic characteristics (water contact angle: 157°). From these results, we deduced that portions of the microstructures were wet and that air gaps existed between the microstructures and the water drops. In this paper we suggest the possibility of the mass production of hydrophobic plastic surfaces and the development of a methodology for the hydrophobic texturing of various polymer surfaces, using the polymer casting method with laser-processed molds.

  4. Comparative analysis of the retention of maxillary denture base with and without border molding using zinc oxide eugenol impression paste

    PubMed Central

    Kaur, Simrat; Datta, Kusum; Gupta, S. K.; Suman, Neelam

    2016-01-01

    Aims and Objectives: The purpose of the study was to determine the effect of border molding on the retention of the maxillary denture base. Materials and Methods: Two special trays, one with full extensions to the periphery and one 2 mm short from the borders were made on the cast obtained from the preliminary impression. Border molding was done on the tray which was short from borders. On both trays, the final impression was made with zinc oxide eugenol impression paste. Heat cure denture bases were fabricated on the prepared casts and retention was measured using specially designed instrument. Observations and Results: Mean force with border molding (2765.0 g) was larger than mean force without border molding (1805.0 g) at P < 0.01 level. In terms of percentage, too, the mean improvement (59.4%) in force of dislodgement was statistically highly significant (i.e. P < 0.01). Clinical Significance: The results of the present study suggest that the dentures made with border molding will provide better retentive force than the dentures made without border molding. PMID:27134447

  5. Electromagnetic augmentation for casting of thin metal sheets

    DOEpatents

    Hull, J.R.

    1987-10-28

    Thin metal sheets are cast by magnetically levitating molten metal deposited in a model within a ferromagnetic yoke and between AC conducting coils and linearly displacing the magnetically levitated liquid metal while it is being cooled by the water-cooled walls of the mold to form a solid metal sheet. A conducting shield is electrically coupled to the molten metal sheet to provide a return path for eddy currents induced in the metal sheet by the current in the AC conducting coils. In another embodiment, a DC conducting coil is coupled to the metal sheet for providing a direct current therein which interacts with the magnetic field to levitate the moving metal sheet. Levitation of the metal sheet in both molten and solid forms reduces its contact pressure with the mold walls while maintaining sufficient engagement therebetween to permit efficient conductive cooling by the mold through which a coolant fluid may be circulated. 8 figs.

  6. LLNL casting technology

    SciTech Connect

    Shapiro, A.B.; Comfort, W.J. III

    1994-01-01

    Competition to produce cast parts of higher quality, lower rejection rate, and lower cost is a fundamental factor in the global economy. To gain an edge on foreign competitors, the US casting industry must cut manufacturing costs and reduce the time from design to market. Casting research and development (R&D) are the key to increasing US compentiveness in the casting arena. Lawrence Livermore National Laboratory (LLNL) is the home of a wide range of R&D projects that push the boundaries of state-of-the art casting. LLNL casting expertise and technology include: casting modeling research and development, including numerical simulation of fluid flow, heat transfer, reaction/solidification kinetics, and part distortion with residual stresses; special facilities to cast toxic material; extensive experience casting metals and nonmetals; advanced measurement and instrumentation systems. Department of Energy (DOE) funding provides the leverage for LLNL to collaborate with industrial partners to share this advanced casting expertise and technology. At the same time, collaboration with industrial partners provides LLNL technologists with broader insights into casting industry issues, casting process data, and the collective, experience of industry experts. Casting R&D is also an excellent example of dual-use technology; it is the cornerstone for increasing US industrial competitiveness and minimizing waste nuclear material in weapon component production. Annual funding for casting projects at LLNL is $10M, which represents 1% of the total LLNL budget. Metal casting accounts for about 80% of the funding. Funding is nearly equally divided between development directed toward US industrial competitiveness and weapon component casting.

  7. LLNL casting technology

    NASA Astrophysics Data System (ADS)

    Shapiro, A. B.; Comfort, W. J., III

    1994-01-01

    Competition to produce cast parts of higher quality, lower rejection rate, and lower cost is a fundamental factor in the global economy. To gain an edge on foreign competitors, the US casting industry must cut manufacturing costs and reduce the time from design to market. Casting research and development (R&D) are the key to increasing US competiveness in the casting arena. Lawrence Livermore National Laboratory (LLNL) is the home of a wide range of R&D projects that push the boundaries of state-of-the art casting. LLNL casting expertise and technology include: casting modeling research and development, including numerical simulation of fluid flow, heat transfer, reaction/solidification kinetics, and part distortion with residual stresses; special facilities to cast toxic material; extensive experience casting metals and nonmetals; advanced measurement and instrumentation systems. Department of Energy (DOE) funding provides the leverage for LLNL to collaborate with industrial partners to share this advanced casting expertise and technology. At the same time, collaboration with industrial partners provides LLNL technologists with broader insights into casting industry issues, casting process data, and the collective experience of industry experts. Casting R&D is also an excellent example of dual-use technology; it is the cornerstone for increasing US industrial competitiveness and minimizing waste nuclear material in weapon component production. Annual funding for casting projects at LLNL is $10M, which represents 1% of the total LLNL budget. Metal casting accounts for about 80% of the funding. Funding is nearly equally divided between development directed toward US industrial competitiveness and weapon component casting.

  8. Facts about Stachybotrys chartarum and Other Molds

    MedlinePlus

    ... Program in Brief Related Issues Resources Quick Links Air Pollution & Respiratory Health Air Quality Asthma Mold What's New ... be removed. Â Top of Page Quick Links Air Pollution & Respiratory Health Air Quality Asthma Mold What's New ...

  9. Contamination Barrier For Contour-Molding Material

    NASA Technical Reports Server (NTRS)

    Adams, James F.

    1988-01-01

    Release agent prevents molding compound from adhering to or contaminating surface. Cleaning agent, Turco 4215 NCLT, forms barrier preventing silicone molding compound from sticking to surface and leaving contaminating residue. Also see MFS-29243.

  10. MOLD-SPECIFIC QUANTITATIVE PCR: THE EMERGING STANDARD IN MOLD ANALYSIS

    EPA Science Inventory

    Molds can cause health problems like infections and allergies, destroy crops, and contaminate our food or pharmaceuticals. We can't avoid molds. Molds are essential players in the biological processes on earth, but we can now identify and quantify the molds that will be most pr...

  11. Enhancements in Magnesium Die Casting Impact Properties

    SciTech Connect

    David Schwam; John F. Wallace; Yulong Zhu; Srinath Viswanathan; Shafik Iskander

    2000-06-30

    The need to produce lighter components in transportation equipment is the main driver in the increasing demand for magnesium castings. In many automotive applications, components can be made of magnesium or aluminum. While being lighter, often times the magnesium parts have lower impact and fatigue properties than the aluminum. The main objective of this study was to identify potential improvements in the impact resistance of magnesium alloys. The most common magnesium alloys in automotive applications are AZ91D, AM50 and AM60. Accordingly, these alloys were selected as the main candidates for the study. Experimental quantities of these alloys were melted in an electrical furnace under a protective atmosphere comprising sulfur hexafluoride, carbon dioxide and dry air. The alloys were cast both in a permanent mold and in a UBE 315 Ton squeeze caster. Extensive evaluation of tensile, impact and fatigue properties was conducted at CWRU on permanent mold and squeeze cast test bars of AZ91, AM60 and AM50. Ultimate tensile strength values between 20ksi and 30ksi were obtained. The respective elongations varied between 25 and 115. the Charpy V-notch impact strength varied between 1.6 ft-lb and 5 ft-lb depending on the alloy and processing conditions. Preliminary bending fatigue evaluation indicates a fatigue limit of 11-12 ksi for AM50 and AM60. This is about 0.4 of the UTS, typical for these alloys. The microstructures of the cast specimens were investigated with optical and scanning electron microscopy. Concomitantly, a study of the fracture toughness in AM60 was conducted at ORNL as part of the study. The results are in line with values published in the literature and are representative of current state of the art in casting magnesium alloys. The experimental results confirm the strong relationship between aluminum content of the alloys and the mechanical properties, in particular the impact strength and the elongation. As the aluminum content increases from about 5

  12. Blow molding of melt processible rubber

    SciTech Connect

    Abell, W.R.; Stuart, R.E.; Myrick, R.E.

    1991-07-01

    This article discusses the advantages of making hollow rubber parts by blow molding thermoplastic elastomers (TPEs) versus conventional rubber processing. It describes the various types of blow molding processes and it provides some insight into the rheological properties of melt processible rubber (MPR) and how MPR should be molded by each of these processes. A number of blow molded applications for MPR are also discussed.

  13. Making Internal Molds Of Long, Curved Tubes

    NASA Technical Reports Server (NTRS)

    Burley, Richard K.

    1989-01-01

    Mold material carried to internal weld joint and removed after impression taken. Remotely operated device makes impression mold of interior surface of tube at weld joint. Mold provides indication of extent of mismatch between members at joint. Maneuvered to weld inspected through curved tube 3 in. in diameter by 50 in. long. Readily adapted to making molds to measure depth of corrosion in boiler tubes or other pipes.

  14. Effect of technological parameters on microstructure in alloy AlCu4Ti using squeeze casting technology

    NASA Astrophysics Data System (ADS)

    Pastirčák, Richard; Ščury, Ján

    2016-06-01

    The paper deals with the impact of technological parameters on the heat transfer coefficient and microstructure in AlCu4Ti alloy using squeeze casting technology. The casting with crystallization under pressure was used, specifically direct squeeze casting method. The goal was to affect crystallization by pressure with a value 100 MPa. The pressure applied to the melt causes a significant increase of the coefficient of heat transfer between the melt and the mold. By rapid cooling the casting was reflected by changes in the structure. On the basis of the measured values of heat flux and heat transfer coefficient were calculated at the interface between the cast and the mold. The observation of microstructure can conclude, there is no significant influencing of the primary phase. As a result of the pressure was reduced porosity.

  15. Columnar to equiaxed transition in high Cr white iron castings

    SciTech Connect

    Dogan, O.N.

    1996-07-15

    White cast irons are frequently used in applications requiring high wear resistance. High Cr white cast irons have a composite microstructure composed of hard (Fe,Cr){sub 7}C{sub 3} carbides in a steel matrix. In thick section castings, long rod-shaped carbides may grow perpendicular to the mold wall to form the columnar zone of the casting, or their long axes may grow in random directions to form equiaxed grains. Previous research has indicated that the equiaxed region of these high Cr white iron castings is much more wear resistant under high stress abrasive conditions than the columnar region, when the carbides are oriented perpendicular to the wear surface. Therefore, in order to maximize their abrasion resistance, it is essential that wear resistant cast parts with thick sections be produced with completely equiaxed macrostructures to maximize their abrasion resistance. In the present study, the effect of both the chemical composition, particularly carbon content, and the pouring superheat of the melt on the macrostructure of high Cr white iron castings is investigated.

  16. Study of the Effect of Shrinkage Porosity on Strength Low Carbon Cast Steel

    NASA Astrophysics Data System (ADS)

    Ol'khovik, E.

    2015-09-01

    Today there are many computer systems for modeling of the casting technology processes. All of them allow calculating the availability and distribution of the shrinkage porosity in the test casting, but this information allows only making changes in existing casting technology. In this paper you obtain the information about changes in the local and structural mechanical properties of the casting in the presence of its volume shrinkage porosity. Article presents the results of direct experimental studies of technological defects (shrinkage and gas porosity) impact on the mechanical properties of low carbon steel castings. Methods of investigation are also disclosed, including the methods for producing of molded samples obtained at different process conditions and the crystallization apparatus which is described for the measuring of the density of the samples. There are the mathematical relationship for the elastic modulus, yield stress, elongation and fatigue characteristics fracture cast steel with low carbon content in the presence of the volumetric shrinkage porosity.

  17. The Mold that Almost Ate the Principal

    ERIC Educational Resources Information Center

    Barry, Wayne; Bishop, Chuck; Byars, Jennifer

    2006-01-01

    New-building mold was a bane for many home construction companies and new homeowners during the 1990s. It was not unusual to read or watch the news and see the tragedy played out in one's local community. Untold, however, is the story of the toll new-building mold can take on school systems and their principals, especially as these mold problems…

  18. Planning an Injection Mold Design Training Program.

    ERIC Educational Resources Information Center

    Allyn, Edward P.

    With the increased use of plastics worldwide the shortage of trained personnel in moldmaking and design for plastic injection molds is becoming critical. Local schools and community colleges should provide courses in mold design and mold making, since most workers presently learn while working under experienced designers on the job. Following this…

  19. Injection Molding of Plastics from Agricultural Materials

    SciTech Connect

    Bhattacharya, M.; Ruan, R.

    2001-02-22

    The objective of this research was to conduct a systematic study to relate injection molding parameters to properties of blends of starch and synthetic polymer. From this study, we wished to develop a thorough understanding of the injection molding process and gain significant insight into designing molds and aiding in developing products cheaply and efficiently.

  20. Attack of the Killer Mold Spores.

    ERIC Educational Resources Information Center

    Moore, Mary

    1999-01-01

    Describes experiences at the Arkansas State University at Jonesboro library when mold was discovered in a large portion of the monograph collection. Discusses causes of mold formation, equipment needed, news media coverage, staff involvement in the cleanup, and possible health hazards from mold. (LRW)

  1. Anisotropic remastering for reducing feature sizes on UV nanoimprint lithography replica molds.

    PubMed

    Lausecker, E; Grydlik, M; Brehm, M; Bergmair, I; Mühlberger, M; Fromherz, T; Bauer, G

    2012-04-27

    We present an approach that uses existing nanoimprint molds and reduces the size of the resulting features significantly via a remastering process utilizing the anisotropic etchant tetramethylammonium hydroxide and a mold casting step. Inverted pyramidal structures and V-grooves were imprinted using these 2.5-dimensional (2.5D) replica molds. Pattern transfer into silicon (Si) substrates was established with an intermediate silicon nitride (SiN(x)) layer that can be etched with a much larger selectivity against the imprint resist than the Si substrate. The 2.5D resist profiles are thus transferred back into binary structures in the SiN(x) layer and subsequently into the Si substrate. A substantial size reduction of the diameter of pits from 91 to 33 nm and the width of lines from 600 to 142 nm was achieved. PMID:22469617

  2. Injection-Molded Soft Magnets Prepared from Fe-Based Metallic Glass: Mechanical and Magnetic Properties

    NASA Astrophysics Data System (ADS)

    Zhong, Tian; Huang, Ran; Huang, Jia; Ouyang, Wei

    2015-10-01

    The injection-molded metallic glass soft magnet is prepared from the powder of melt-spun ribbon of Fe36Co36B20Si4Nb4 glassy alloy and Nylon 6,6 of wt.% from 5 to 20 via the polymer injection molding technology. The product is characterized by the SEM, mechanical, and magnetic test. The results indicate that this type of materials has comparable mechanical properties and morphological feature with the conventional injection-molded NdFeB magnet and exhibits excellent soft magnetic behaviors. The magnetic properties of the injected magnets are compared with the raw metallic glass, solvent-casted resin bonding magnets, and thermal-treated magnets to confirm that the processing temperature of Nylon injection does not affect the magnetism. The injection technology is a practical processing method to be applied on the metallic glass for potential usage.

  3. Anisotropic remastering for reducing feature sizes on UV nanoimprint lithography replica molds

    NASA Astrophysics Data System (ADS)

    Lausecker, E.; Grydlik, M.; Brehm, M.; Bergmair, I.; Mühlberger, M.; Fromherz, T.; Bauer, G.

    2012-04-01

    We present an approach that uses existing nanoimprint molds and reduces the size of the resulting features significantly via a remastering process utilizing the anisotropic etchant tetramethylammonium hydroxide and a mold casting step. Inverted pyramidal structures and V-grooves were imprinted using these 2.5-dimensional (2.5D) replica molds. Pattern transfer into silicon (Si) substrates was established with an intermediate silicon nitride (SiNx) layer that can be etched with a much larger selectivity against the imprint resist than the Si substrate. The 2.5D resist profiles are thus transferred back into binary structures in the SiNx layer and subsequently into the Si substrate. A substantial size reduction of the diameter of pits from 91 to 33 nm and the width of lines from 600 to 142 nm was achieved.

  4. Gray Mold or Botrytis Blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gray mold, caused by Botrytis cinerea can cause an intermittent decay of leaves or seed production organs of beet. The disease is not usually economically important on sugar beet, but can be severe enough to need control on swiss chard. This chapter describes the disease and pathogen and mentions ...

  5. ALLERGIC POTENTIAL OF INDOOR MOLDS

    EPA Science Inventory

    Many fungi have been associated with allergic lung disease, but few are well studied and even fewer allergens of fungal origin are well characterized. Exposure to damp moldy environments has been associated with the exacerbation of asthma, but the role of molds in the induction o...

  6. ANIMAL MODELS OF MOLD ALLERGY

    EPA Science Inventory

    The concept of molds as causative agents for allergy/asthma is not new. In fact many fungal genera have been associated with allergic lung disease, but only a few fungi are well studied and even fewer fungal allergens well characterized. The complexity and variety of fungal pro...

  7. Molded Concrete Center Mine Wall

    NASA Technical Reports Server (NTRS)

    Lewis, E. V.

    1987-01-01

    Proposed semiautomatic system forms concrete-foam wall along middle of coal-mine passage. Wall helps support roof and divides passage into two conduits needed for ventilation of coal face. Mobile mold and concrete-foam generator form sections of wall in place.

  8. Is Mold the New Asbestos?

    ERIC Educational Resources Information Center

    Colgan, Craig

    2003-01-01

    Mold and indoor air quality (IAQ) are matters of major concern to architects and their educational clients. The Environmental Protection Agency's Indoor Air Quality Tools for Schools program offers help to districts seeking to tackle IAQ issues. Strengthening community relations is one way to be ready in case of a bad environmental or IAQ report.…

  9. Evaluation of electroslag castings

    SciTech Connect

    Judkins, R.R.; Sikka, V.K.

    1985-01-01

    Results of evaluations of electroslag castings of ferritic (2-1/4 Cr-1 Mo and 9 Cr-1 Mo) and austenitic (CF8M or type 316) steels are presented. The castings have been characterized for surface finish, cracking, solidification structure, chemical composition, hardness, ferrite distribution, tensile properties, Charpy impact properties, and creep properties. Pertinent data are compared with equivalent data for sand castings and wrought products of the same materials. Based on the results of these studies, the properties of electroslag castings compare favorably with those of sand castings and wrought materials.

  10. Numerical simulation of the casting process of titanium tooth crowns and bridges.

    PubMed

    Wu, M; Augthun, M; Wagner, I; Sahm, P R; Spiekermann, H

    2001-06-01

    The objectives of this paper were to simulate the casting process of titanium tooth crowns and bridges; to predict and control porosity defect. A casting simulation software, MAGMASOFT, was used. The geometry of the crowns with fine details of the occlusal surface were digitized by means of laser measuring technique, then converted and read in the simulation software. Both mold filling and solidification were simulated, the shrinkage porosity was predicted by a "feeding criterion", and the gas pore sensitivity was studied based on the mold filling and solidification simulations. Two types of dental prostheses (a single-crown casting and a three-unit-bridge) with various sprue designs were numerically "poured", and only one optimal design for each prosthesis was recommended for real casting trial. With the numerically optimized design, real titanium dental prostheses (five replicas for each) were made on a centrifugal casting machine. All the castings endured radiographic examination, and no porosity was detected in the cast prostheses. It indicates that the numerical simulation is an efficient tool for dental casting design and porosity control. PMID:15348262

  11. Yield improvement and defect reduction in steel casting

    SciTech Connect

    Kent Carlson

    2004-03-16

    This research project investigated yield improvement and defect reduction techniques in steel casting. Research and technology development was performed in the following three specific areas: (1) Feeding rules for high alloy steel castings; (2) Unconventional yield improvement and defect reduction techniques--(a) Riser pressurization; and (b) Filling with a tilting mold; and (3) Modeling of reoxidation inclusions during filling of steel castings. During the preparation of the proposal for this project, these areas were identified by the High Alloy Committee and Carbon and Low Alloy Committee of the Steel Founders' Society of America (SFSA) as having the highest research priority to the steel foundry industry. The research in each of the areas involved a combination of foundry experiments, modeling and simulation. Numerous SFSA member steel foundries participated in the project through casting trials and meetings. The technology resulting from this project will result in decreased scrap and rework, casting yield improvement, and higher quality steel castings produced with less iteration. This will result in considerable business benefits to steel foundries, primarily due to reduced energy and labor costs, increased capacity and productivity, reduced lead-time, and wider use and application of steel castings. As estimated using energy data provided by the DOE, the technology produced as a result of this project will result in an energy savings of 2.6 x 10{sup 12} BTU/year. This excludes the savings that were anticipated from the mold tilting research. In addition to the energy savings, and corresponding financial savings this implies, there are substantial environmental benefits as well. The results from each of the research areas listed above are summarized.

  12. Rapid fabrication of microfluidic PDMS devices from reusable PDMS molds using laser ablation

    NASA Astrophysics Data System (ADS)

    Isiksacan, Ziya; Tahsin Guler, M.; Aydogdu, Berkan; Bilican, Ismail; Elbuken, Caglar

    2016-03-01

    The conventional fabrication methods for microfluidic devices require cleanroom processes that are costly and time-consuming. We present a novel, facile, and low-cost method for rapid fabrication of polydimethylsiloxane (PDMS) molds and devices. The method consists of three main fabrication steps: female mold (FM), male mold (MM), and chip fabrication. We use a CO2 laser cutter to pattern a thin, spin-coated PDMS layer for FM fabrication. We then obtain reusable PDMS MM from the FM using PDMS/PDMS casting. Finally, a second casting step is used to replicate PDMS devices from the MM. Demolding of one PDMS layer from another is carried out without any potentially hazardous chemical surface treatment. We have successfully demonstrated that this novel method allows fabrication of microfluidic molds and devices with precise dimensions (thickness, width, length) using a single material, PDMS, which is very common across microfluidic laboratories. The whole process, from idea to device testing, can be completed in 1.5 h in a standard laboratory.

  13. Injection molding ceramics to high green densities

    NASA Technical Reports Server (NTRS)

    Mangels, J. A.; Williams, R. M.

    1983-01-01

    The injection molding behavior of a concentrated suspension of Si powder in wax was studied. It was found that the injection molding behavior was a function of the processing techniques used to generate the powder. Dry ball-milled powders had the best molding behavior, while air classified and impact-milled powders demonstrated poorer injection moldability. The relative viscosity of these molding batches was studied as a function of powder properties: distribution shape, surface area, packing density, and particle morphology. The experimental behavior, in all cases, followed existing theories. The relative viscosity of an injection molding composition composed of dry ball-milled powders could be expressed using Farris' relation.

  14. Estimation of Time-Temperature-Transformation Diagrams of Mold Powder Slags from Thermo-analysis of Non-isothermal Crystallization

    NASA Astrophysics Data System (ADS)

    Maldonado, Yadira G.; Barraza de la P., Claudia; Rodríguez A., Sergio; Castillejos E., A. Humberto; Thomas, Brian G.

    2014-09-01

    The temperature range across the mold powder slag in the interfacial gap between the continuous casting mold and strand leads through different transformation behavior into crystalline phases. The transformation rates play a key role in determining the proportion of glassy and crystalline phases present, and thus greatly influence mold heat transfer and lubrication. Although thermal analysis has held great promise to quantify the crystallization of mold slags, so far the information it has provided is scarce. This work shows how differential scanning calorimetry, DSC, data allow evaluation of Time-Temperature-Transformation, TTT, diagrams of mold powder slags, when analyzed with the induction period and the Kissinger methods. The data required for estimating this important tool for the analysis and design of mold powders are onset temperature, T i, peak maximum temperature, T m, shape index, S, and conversion at peak maximum, x m, of the crystallization peaks appearing on thermograms obtained at various heating and cooling rates, ϕ or -ϕ, respectively. Industrial mold powders for casting low- and medium-carbon steels were analyzed to obtain TTT diagrams which correctly portray their different crystallization behavior. The diagrams reveal the start and end curves of the crystalline phases forming at each DSC crystallization peak. The estimated TTT curves present a correct picture of the degree of transformation observed in glass disks (~3 mm thick) treated isothermally for specified time intervals, quenched and examined with a scanning electron microscope. Additionally, the procedure developed for DSC-based TTT diagram calculation is supported by the good agreement between expected transformations and qualitative or quantitative X-ray diffraction results obtained from mold glass-powdered samples treated isothermally in a muffle furnace.

  15. Estimation of Time-Temperature-Transformation Diagrams of Mold Powder Slags from Thermo-analysis of Non-isothermal Crystallization

    NASA Astrophysics Data System (ADS)

    Maldonado, Yadira G.; Barraza de la P., Claudia; Rodríguez A., Sergio; Castillejos E., A. Humberto; Thomas, Brian G.

    2015-02-01

    The temperature range across the mold powder slag in the interfacial gap between the continuous casting mold and strand leads through different transformation behavior into crystalline phases. The transformation rates play a key role in determining the proportion of glassy and crystalline phases present, and thus greatly influence mold heat transfer and lubrication. Although thermal analysis has held great promise to quantify the crystallization of mold slags, so far the information it has provided is scarce. This work shows how differential scanning calorimetry, DSC, data allow evaluation of Time-Temperature-Transformation, TTT, diagrams of mold powder slags, when analyzed with the induction period and the Kissinger methods. The data required for estimating this important tool for the analysis and design of mold powders are onset temperature, T i, peak maximum temperature, T m, shape index, S, and conversion at peak maximum, x m, of the crystallization peaks appearing on thermograms obtained at various heating and cooling rates, ϕ or - ϕ, respectively. Industrial mold powders for casting low- and medium-carbon steels were analyzed to obtain TTT diagrams which correctly portray their different crystallization behavior. The diagrams reveal the start and end curves of the crystalline phases forming at each DSC crystallization peak. The estimated TTT curves present a correct picture of the degree of transformation observed in glass disks (~3 mm thick) treated isothermally for specified time intervals, quenched and examined with a scanning electron microscope. Additionally, the procedure developed for DSC-based TTT diagram calculation is supported by the good agreement between expected transformations and qualitative or quantitative X-ray diffraction results obtained from mold glass-powdered samples treated isothermally in a muffle furnace.

  16. Initial solidification phenomena in continuous casting

    NASA Astrophysics Data System (ADS)

    Badri, Adam

    Continuous casting is the main process route for the mass production of steel today, yielding in excess of 560 million tons annually, corresponding to 80% of total steel production worldwide. As with any process, as improvements are introduced and quality is enhanced, there is the ever greater push to reduce problems that were once minor. The restrictions on quality for certain products require that defects be kept to a minimum. Currently, the industry has developed a wealth of experience in how to deal with slabs with oscillation marks. However, these practices are circumventions of the symptoms of the problems, not solutions for the causes. By understanding the formation mechanism, one can then develop practices based on a logical consideration oft he causes. The goals of this current work were to develop a mold simulator that could replicate the surface quality of industrial slabs. The techniques developed allowed for a more detailed examination of the heat transfer interactions during continuous casting, such that the variations of heat flux due to irregular solidification could be observed. It is shown that the mechanisms proposed in the literature are not individually sufficient for the formation of an oscillation mark, but several are necessary and must occur in concert for one to form. A mechanism is proposed for the formation of oscillation marks based upon the experimental results. This hypothesis is formulated as a series of necessary conditions that must be satisfied for an oscillation mark to be formed. This hypothesis is described, and shown to be in agreement with the trends observed and reported in the literature. It can explain both the overflow- and depression-type mark seen in industrial slabs. Additionally, this hypothesis was successfully used as a method of predicting the locations of oscillation marks on cast shells based upon the mold heat transfer measurements.

  17. Advanced manufacturing methods for chalcogenide molded optics

    NASA Astrophysics Data System (ADS)

    Cogburn, Gabriel

    2011-06-01

    As Chalcogenide glass and Precision Molded Optics (PMO) have developed and matured to a point of being accepted as replacements for Germanium Single Point Diamond Turned (SPDT) optics; technological research is being dedicated to developing infrared PMO that can be used in a broader application base. These include laser arrays, large aperture molded chalcogenide optics, and molded in mount infrared optics. This paper presents applications for infrared laser arrays and the corresponding optics that must be closely mechanically mounted to avoid clipping the beams. Different molding and mounting techniques will be discussed to solve this issue which include; dicing chalcogenide optic lenses, molded in mount chalcogenide optics and stepped optic shape molding for mounting purposes. Accompanying the research and discussion of these techniques will be experiments and molded chalcogenide glass lenses showing the results and application for each lens type.

  18. Assessment of Computer Simulation Software and Process Data for High Pressure Die Casting of Magnesium

    SciTech Connect

    Sabau, Adrian S; Hatfield, Edward C; Dinwiddie, Ralph Barton; Kuwana, Kazunori; Viti, Valerio; Hassan, Mohamed I; Saito, Kozo

    2007-09-01

    Computer software for the numerical simulation of solidification and mold filling is an effective design tool for cast structural automotive magnesium components. A review of commercial software capabilities and their validation procedures was conducted. Aside form the software assessment, the program addressed five main areas: lubricant degradation, lubricant application, gate atomization, and heat transfer at metal mold interfaces. A test stand for lubricant application was designed. A sensor was used for the direct measurement of heat fluxes during lubricant application and casting solidification in graphite molds. Spray experiments were conducted using pure deionized water and commercial die lubricants. The results show that the sensor can be used with confidence for measuring heat fluxes under conditions specific to the die lube application. The data on heat flux was presented in forms suitable for use in HPDC simulation software. Severe jet breakup and atomization phenomena are likely to occur due to high gate velocities in HPDC. As a result of gate atomization, droplet flow affects the mold filling pattern, air entrapment, skin formation, and ensuing defects. Warm water analogue dies were designed for obtaining experimental data on mold filling phenomena. Data on break-up jet length, break-up pattern, velocities, and droplet size distribution were obtained experimentally and was used to develop correlations for jet break-up phenomena specific to die casting gate configurations.

  19. Modeling on Fluid Flow and Inclusion Motion in Centrifugal Continuous Casting Strands

    NASA Astrophysics Data System (ADS)

    Wang, Qiangqiang; Zhang, Lifeng; Sridhar, Seetharaman

    2016-05-01

    During the centrifugal continuous casting process, unreasonable casting parameters can cause violent level fluctuation, serious gas entrainment, and formation of frozen shell pieces at the meniscus. Thus, in the current study, a three-dimensional multiphase turbulent model was established to study the transport phenomena during centrifugal continuous casting process. The effects of nozzle position, casting and rotational speed on the flow pattern, centrifugal force acting on the molten steel, level fluctuation, gas entrainment, shear stress on mold wall, and motion of inclusions during centrifugal continuous casting process were investigated. Volume of Fluid model was used to simulate the molten steel-air two-phase. The level fluctuation and the gas entrainment during casting were calculated by user-developed subroutines. The trajectory of inclusions in the rotating system was calculated using the Lagrangian approach. The results show that during centrifugal continuous casting, a large amount of gas was entrained into the molten steel, and broken into bubbles of various sizes. The greater the distance to the mold wall, the smaller the centrifugal force. Rotation speed had the most important influence on the centrifugal force distribution at the side region. Angular moving angle of the nozzle with 8° and keeping the rotation speed with 60 revolutions per minute can somehow stabilize the level fluctuation. The increase of angular angle of nozzle from 8 to 18 deg and rotation speed from 40 to 80 revolutions per minute favored to decrease the total volume of entrained bubbles, while the increase of distance of nozzle moving left and casting speed had reverse effects. The trajectories of inclusions in the mold were irregular, and then rotated along the strand length. After penetrating a certain distance, the inclusions gradually moved to the center of billet and gathered there. More work, such as the heat transfer, the solidification, and the inclusions entrapment

  20. Modeling on Fluid Flow and Inclusion Motion in Centrifugal Continuous Casting Strands

    NASA Astrophysics Data System (ADS)

    Wang, Qiangqiang; Zhang, Lifeng; Sridhar, Seetharaman

    2016-08-01

    During the centrifugal continuous casting process, unreasonable casting parameters can cause violent level fluctuation, serious gas entrainment, and formation of frozen shell pieces at the meniscus. Thus, in the current study, a three-dimensional multiphase turbulent model was established to study the transport phenomena during centrifugal continuous casting process. The effects of nozzle position, casting and rotational speed on the flow pattern, centrifugal force acting on the molten steel, level fluctuation, gas entrainment, shear stress on mold wall, and motion of inclusions during centrifugal continuous casting process were investigated. Volume of Fluid model was used to simulate the molten steel-air two-phase. The level fluctuation and the gas entrainment during casting were calculated by user-developed subroutines. The trajectory of inclusions in the rotating system was calculated using the Lagrangian approach. The results show that during centrifugal continuous casting, a large amount of gas was entrained into the molten steel, and broken into bubbles of various sizes. The greater the distance to the mold wall, the smaller the centrifugal force. Rotation speed had the most important influence on the centrifugal force distribution at the side region. Angular moving angle of the nozzle with 8° and keeping the rotation speed with 60 revolutions per minute can somehow stabilize the level fluctuation. The increase of angular angle of nozzle from 8 to 18 deg and rotation speed from 40 to 80 revolutions per minute favored to decrease the total volume of entrained bubbles, while the increase of distance of nozzle moving left and casting speed had reverse effects. The trajectories of inclusions in the mold were irregular, and then rotated along the strand length. After penetrating a certain distance, the inclusions gradually moved to the center of billet and gathered there. More work, such as the heat transfer, the solidification, and the inclusions entrapment

  1. Simulation Study of Al-1Mn/Al-10Si Circular Clad Ingots Prepared by Direct Chill Casting

    NASA Astrophysics Data System (ADS)

    Wu, Li; Kang, Huijun; Chen, Zongning; Fu, Ying; Wang, Tongmin

    2016-02-01

    A modified direct chill casting process based on Novelis FusionTM Technology co-casting process was used recently to prepare Al-1Mn/Al-10Si circular clad ingots. In the current study, a comprehensive simulation model was developed to investigate the direct chill casting process for preparing the Al-1Mn/Al-10Si circular clad ingots, and a parametric study and experimental research of the direct chill casting process was conducted to explore potential success and failure casting conditions. The simulation results revealed the bonding mechanism of the Al-1Mn/Al-10Si interface in the direct chill casting process and identified the effect of certain parameters on casting performance. The results indicated that the effect of casting speed and Al-1Mn casting temperature on the variations of the minimum solid fraction of Al-1Mn at the interface is stronger than that of cooling water flow rate in inner mold, while Al-10Si casting temperature is the weakest of the four casting parameters. The corresponding experimental results verified that Al-1Mn/Al-10Si circular clad ingot with acceptable metallurgical bonding can be successfully prepared by direct chill casting process under the proper casting parameters. The thickness of diffusion zone is about 40 μm, and the fractured position in tensile test was located in the Al-1Mn alloy side which indicated the strength of the interfacial region is higher than that of Al-1Mn alloy.

  2. Rapid mesh generation for finite element analysis of investment castings

    SciTech Connect

    Lober, R.R.; Bohnhoff, W.J.; Meyers, R.J.

    1992-11-01

    FASTCAST is a Sandia National Laboratories program to produce investment cast prototypical hardware faster by integrating experimental and computational technologies into the casting process. FASTCAST uses the finite element method to characterize the metal flow and solidification processes to reduce uncertainty in the mold design. For the casting process to benefit from finite element analysis, analysis results must be available in a very short time frame. By focusing on the bottleneck of finite element model creation, automated mesh generation can drastically reduce the time span between geometry definition (design) and accurate analysis results. The increased availability of analysis results will diminish the need for trial and error approaches to acquiring production worthy mold and gating systems for investment casting. The CUBIT meshing tool kit is being developed to address the need for rapid mesh generation. CUBIT is being designed to effectively automate the generation of quadrilateral and hexahedral elements. It is a solid-modeler based, two- and three-dimensional preprocessor that prepares solid models for finite element analysis. CUBIT contains several meshing algorithms including two- and three-dimensional mapping, two- and three-dimensional paving (patented), and a general two and one-half dimensional sweeper based upon the plastering algorithm. This paper describes progress in the development of the CUBIT meshing toolkit.

  3. Rapid mesh generation for finite element analysis of investment castings

    SciTech Connect

    Lober, R.R.; Bohnhoff, W.J.; Meyers, R.J.

    1992-01-01

    FASTCAST is a Sandia National Laboratories program to produce investment cast prototypical hardware faster by integrating experimental and computational technologies into the casting process. FASTCAST uses the finite element method to characterize the metal flow and solidification processes to reduce uncertainty in the mold design. For the casting process to benefit from finite element analysis, analysis results must be available in a very short time frame. By focusing on the bottleneck of finite element model creation, automated mesh generation can drastically reduce the time span between geometry definition (design) and accurate analysis results. The increased availability of analysis results will diminish the need for trial and error approaches to acquiring production worthy mold and gating systems for investment casting. The CUBIT meshing tool kit is being developed to address the need for rapid mesh generation. CUBIT is being designed to effectively automate the generation of quadrilateral and hexahedral elements. It is a solid-modeler based, two- and three-dimensional preprocessor that prepares solid models for finite element analysis. CUBIT contains several meshing algorithms including two- and three-dimensional mapping, two- and three-dimensional paving (patented), and a general two and one-half dimensional sweeper based upon the plastering algorithm. This paper describes progress in the development of the CUBIT meshing toolkit.

  4. Precision compression molding of chalcogenide glass optical elements

    NASA Astrophysics Data System (ADS)

    Qi, Chaowei; Ma, Tao; Chen, Fan

    2013-12-01

    Precision glass molding process (GMP) is a promising process to manufacture small precision optical elements in large volume. In this paper, we report on the fabrication of a molded chalcogenide glass lens as an optical element. A set of mold was designed and manufactured with silicon carbide material for the molding test. The structure of the mold set was semi-closed and detachable which can make the molded lens easy releasing with non-invasion. The surfaces of the mold cores are coated with thin protecting DLC film to relieve adhesion problem and increase the working life. Experiments were also performed using a precision glass molding machine Toshiba GMP-311V to determine the molding parameters i.e. molding temperature, pressure and cooling rate. The glass lens breakage during precision molding process was analyzed according to the glass property and the molding parameters. By modifying the mold design and optimization the processing parameters, ultimately achieve the desired molded lens.

  5. Clean Ferrous Casting Technology Research. Annual report, September 29, 1993--September 28, 1994

    SciTech Connect

    Stefanescu, D.M.; Lane, A.M.; Giese, S.R.; Pattabhi, R.; El-Kaddah, N.H.; Griffin, J.; Bates, C.E.; Piwonka, T.S.

    1994-10-01

    This annual report covers work performed in the first year of research on Clean Ferrous Casting Technology Research. During this year the causes of penetration of cast iron in sand molds were defined and a program which predicts the occurrence of penetration was written and verified in commercial foundries. Calculations were made to size a reaction chamber to remove inclusions from liquid steel using electromagnetic force and the chamber was built. Finally, significant progress was made in establishing pouring practices which avoid re-oxidation of steel during pouring application of revised pouring practices have led to reduced inclusion levels in commercially poured steel castings.

  6. Anisotropic constitutive model and FE simulation of the sintering process of slip cast traditional porcelain

    NASA Astrophysics Data System (ADS)

    Sarbandi, B.; Besson, J.; Boussuge, M.; Ryckelynck, D.

    2010-06-01

    Slip cast ceramic components undergo both sintering shrinkage and creep deformation caused by gravity during the firing cycle. In addition sintering may be anisotropic due to the development of preferential directions during slip casting. Both phenomena induce complex deformations of parts which make the design of casting molds difficult. To help solving this problem, anisotropic constitutive equations are proposed to represent the behavior of the ceramic compacts during sintering. The model parameters are identified using tests allowing to characterize both sintering and creep. The model was implemented in a finite element software and used to simulate the deformation of a traditional ceramic object during sintering.

  7. Anisotropic constitutive model and FE simulation of the sintering process of slip cast traditional porcelain

    SciTech Connect

    Sarbandi, B.; Besson, J.; Boussuge, M.; Ryckelynck, D.

    2010-06-15

    Slip cast ceramic components undergo both sintering shrinkage and creep deformation caused by gravity during the firing cycle. In addition sintering may be anisotropic due to the development of preferential directions during slip casting. Both phenomena induce complex deformations of parts which make the design of casting molds difficult. To help solving this problem, anisotropic constitutive equations are proposed to represent the behavior of the ceramic compacts during sintering. The model parameters are identified using tests allowing to characterize both sintering and creep. The model was implemented in a finite element software and used to simulate the deformation of a traditional ceramic object during sintering.

  8. Fabrication of hierarchically structured superhydrophobic PDMS surfaces by Cu and CuO casting

    NASA Astrophysics Data System (ADS)

    Migliaccio, Christopher P.; Lazarus, Nathan

    2015-10-01

    Poly(dimethylsiloxane) (PDMS) films decorated with hierarchically structured pillars are cast from large area copper and copper oxide negative molds. The molds are fabricated using a single patterning step and electroplating. The process of casting structured PDMS films is simpler and cheaper than alternatives based on deep reactive ion etching or laser roughening of bulk silicone. Texture imparted to the pillars from the mold walls renders the PDMS films superhydrophobic, with the contact angle/hysteresis of the most non-wetting surfaces measuring 164°/9° and 158°/10° for surfaces with and without application of a low surface energy coating. The usefulness of patterned PDMS films as a "self-cleaning" solar cell module covering is demonstrated and other applications are discussed.

  9. Casting Apparatus Including A Gas Driven Molten Metal Injector And Method

    DOEpatents

    Trudel, David R.; Meyer, Thomas N.; Kinosz, Michael J.; Arnaud, Guy; Bigler, Nicolas

    2003-06-17

    The filtering molten metal injector system includes a holder furnace, a casting mold supported above the holder furnace, and at least one molten metal injector supported from a bottom side of the casting mold. The holder furnace contains a supply of molten metal. The mold defines a mold cavity for receiving the molten metal from the holder furnace. The molten metal injector projects into the holder furnace. The molten metal injector includes a cylinder defining a piston cavity housing a reciprocating piston for pumping the molten metal upward from the holder furnace to the mold cavity. The cylinder and piston are at least partially submerged in the molten metal when the holder furnace contains the molten metal. The cylinder or the piston includes a molten metal intake for receiving the molten metal into the piston cavity when the holder furnace contains molten metal. A conduit connects the piston cavity to the mold cavity. A molten metal filter is located in the conduit for filtering the molten metal passing through the conduit during the reciprocating movement of the piston. The molten metal intake may be a valve connected to the cylinder, a gap formed between the piston and an open end of the cylinder, an aperture defined in the sidewall of the cylinder, or a ball check valve incorporated into the piston. A second molten metal filter preferably covers the molten metal intake to the injector.

  10. High Temperature Transfer Molding Resins

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Smith, Joseph G., Jr. (Inventor); Hergenrother, Paul M. (Inventor)

    2000-01-01

    High temperature resins containing phenylethynyl groups that are processable by transfer molding have been prepared. These phenylethynyl containing oligomers were prepared from aromatic diamines containing phenylethynyl groups and various ratios of phthalic anhydride and 4-phenylethynlphthalic anhydride in glacial acetic acid to form a mixture of imide compounds in one step. This synthetic approach is advantageous since the products are a mixture of compounds and consequently exhibit a relatively low melting temperature. In addition, these materials exhibit low melt viscosities which are stable for several hours at 210-275 C, and since the thermal reaction of the phenylethynyl group does not occur to any appreciable extent at temperatures below 300 C, these materials have a broad processing window. Upon thermal cure at approximately 300-350 C, the phenylethynyl groups react to provide a crosslinked resin system. These new materials exhibit excellent properties and are potentially useful as adhesives, coatings, films, moldings and composite matrices.

  11. Compression molding of aerogel microspheres

    DOEpatents

    Pekala, R.W.; Hrubesh, L.W.

    1998-03-24

    An aerogel composite material produced by compression molding of aerogel microspheres (powders) mixed together with a small percentage of polymer binder to form monolithic shapes in a cost-effective manner is disclosed. The aerogel composites are formed by mixing aerogel microspheres with a polymer binder, placing the mixture in a mold and heating under pressure, which results in a composite with a density of 50--800 kg/m{sup 3} (0.05--0.80 g/cc). The thermal conductivity of the thus formed aerogel composite is below that of air, but higher than the thermal conductivity of monolithic aerogels. The resulting aerogel composites are attractive for applications such as thermal insulation since fabrication thereof does not require large and expensive processing equipment. In addition to thermal insulation, the aerogel composites may be utilized for filtration, ICF target, double layer capacitors, and capacitive deionization. 4 figs.

  12. Compression molding of aerogel microspheres

    DOEpatents

    Pekala, Richard W.; Hrubesh, Lawrence W.

    1998-03-24

    An aerogel composite material produced by compression molding of aerogel microspheres (powders) mixed together with a small percentage of polymer binder to form monolithic shapes in a cost-effective manner. The aerogel composites are formed by mixing aerogel microspheres with a polymer binder, placing the mixture in a mold and heating under pressure, which results in a composite with a density of 50-800 kg/m.sup.3 (0.05-0.80 g/cc). The thermal conductivity of the thus formed aerogel composite is below that of air, but higher than the thermal conductivity of monolithic aerogels. The resulting aerogel composites are attractive for applications such as thermal insulation since fabrication thereof does not require large and expensive processing equipment. In addition to thermal insulation, the aerogel composites may be utilized for filtration, ICF target, double layer capacitors, and capacitive deionization.

  13. Development of a CFD code for casting simulation

    NASA Technical Reports Server (NTRS)

    Murph, Jesse E.

    1992-01-01

    The task of developing a computational fluid dynamics (CFD) code to accurately model the mold filling phase of a casting operation was accomplished in a systematic manner. First the state-of-the-art was determined through a literature search, a code search, and participation with casting industry personnel involved in consortium startups. From this material and inputs from industry personnel, an evaluation of the currently available codes was made. It was determined that a few of the codes already contained sophisticated CFD algorithms and further validation of one of these codes could preclude the development of a new CFD code for this purpose. With industry concurrence, ProCAST was chosen for further evaluation. Two benchmark cases were used to evaluate the code's performance using a Silicon Graphics Personal Iris system. The results of these limited evaluations (because of machine and time constraints) are presented along with discussions of possible improvements and recommendations for further evaluation.

  14. Development and Demonstration of Adanced Tooling Alloys for Molds and Dies

    SciTech Connect

    Kevin M. McHugh; Enrique J. Lavernia

    2006-01-01

    This report summarizes research results in the project Development and Demonstration of Advanced Tooling Alloys for Molds and Dies. Molds, dies and related tooling are used to manufacture most of the plastic and metal products we use every day. Conventional fabrication of molds and dies involves a multiplicity of machining, benching and heat treatment unit operations. This approach is very expensive and time consuming. Rapid Solidifcation Process (RSP) Tooling is a spray-forming technology tailored for producing molds and dies. The appraoch combines rapid solidifcation processing and net-shape materials processing in a single step. An atomized spray of a tool-forming alloy, typically a tool steel, is deposited onto an easy-to-form tool pattern to replicate the pattern's shape and surface features. By so doing, the approach eliminates many machining operations in conventional mold making, significantly reducing cost, lead time and energy. Moreover, rapid solidification creates unique microstructural features by suppressing carbide precipitation and growth, and creating metastable phases. This can result in unique material properties following heat treatment. Spray-formed and aged tool steel dies have exhibited extended life compared to conventional dies in many forming operations such as forging, extrusion and die casting. RSP Tooling technolocy was commercialized with the formation of RSP Tooling, LLC in Solon, Oh.

  15. Lost Mold Rapid Infiltration Forming of Mesoscale Ceramics: Part 1, Fabrication

    PubMed Central

    Antolino, Nicholas E.; Hayes, Gregory; Kirkpatrick, Rebecca; Muhlstein, Christopher L.; Frecker, Mary I.; Mockensturm, Eric M.; Adair, James H.

    2009-01-01

    Free-standing mesoscale (340 μm × 30 μm × 20 μm) bend bars with an aspect ratio over 15:1 and an edge resolution as fine as a single grain diameter (∼400 nm) have been fabricated in large numbers on refractory ceramic substrates by combining a novel powder processing approach with photoresist molds and an innovative lost-mold thermal process. The colloid and interfacial chemistry of the nanoscale zirconia particulates has been modeled and used to prepare highly concentrated suspensions. Engineering solutions to challenges in mold fabrication and casting have yielded free-standing, crack-free parts. Molds are fabricated using high-aspect-ratio photoresist on ceramic substrates. Green parts are formed using a rapid infiltration method that exploits the shear thinning behavior of the highly concentrated ceramic suspension in combination with gelcasting. The mold is thermally decomposed and the parts are sintered in place on the ceramic substrate. Chemically aided attrition milling disperses and concentrates the as-received 3Y-TZP powder to produce a dense, fine-grained sintered microstructure. Initial three-point bend strength data are comparable to that of conventional zirconia; however, geometric irregularities (e.g., trapezoidal cross sections) are present in this first generation and are discussed with respect to the distribution of bend strength. PMID:19809595

  16. Onychomycosis due to opportunistic molds*

    PubMed Central

    Martínez-Herrera, Erick Obed; Arroyo-Camarena, Stefanie; Tejada-García, Diana Luz; Porras-López, Carlos Francisco; Arenas, Roberto

    2015-01-01

    BACKGROUND: Onychomycosis are caused by dermatophytes and Candida, but rarely by non- dermatophyte molds. These opportunistic agents are filamentous fungi found as soil and plant pathogens. OBJECTIVES: To determine the frequency of opportunistic molds in onychomycosis. METHODS: A retrospective analysis of 4,220 cases with onychomycosis, diagnosed in a 39-month period at the Institute of Dermatology and Skin surgery "Prof. Dr. Fernando A. Cordero C." in Guatemala City, and confirmed with a positive KOH test and culture. RESULTS: 32 cases (0.76%) of onychomycosis caused by opportunistic molds were confirmed. The most affected age group ranged from 41 to 65 years (15 patients, 46.9%) and females were more commonly affected (21 cases, 65.6%) than males. Lateral and distal subungual onychomycosis (OSD-L) was detected in 20 cases (62.5%). The microscopic examination with KOH showed filaments in 19 cases (59.4%), dermatophytoma in 9 cases (28.1%), spores in 2 cases (6.25%), and filaments and spores in 2 cases (6.25%). Etiologic agents: Aspergillus sp., 11 cases (34.4%); Scopulariopsis brevicaulis, 8 cases (25.0%); Cladosporium sp., 3 cases (9.4%); Acremonium sp., 2 cases (6.25%); Paecilomyces sp., 2 cases (6.25%); Tritirachium oryzae, 2 cases (6.25%); Fusarium sp., Phialophora sp., Rhizopus sp. and Alternaria alternate, 1 case (3.1%) each. CONCLUSIONS: We found onychomycosis by opportunistic molds in 0.76% of the cases and DLSO was present in 62.5%. The most frequent isolated etiological agents were: Aspergillus sp. and Scopulariopsis brevicaulis. PMID:26131862

  17. Die Soldering in Aluminium Die Casting

    SciTech Connect

    Han, Q.; Kenik, E.A.; Viswanathan, S.

    2000-03-15

    Two types of tests, dipping tests and dip-coating tests were carried out on small steel cylinders using pure aluminum and 380 alloy to investigate the mechanism of die soldering during aluminum die casting. Optical and scanning electron microscopy were used to study the morphology and composition of the phases formed during soldering. A soldering mechanism is postulated based on experimental observations. A soldering critical temperature is postulated at which iron begins to react with aluminum to form an aluminum-rich liquid phase and solid intermetallic compounds. When the temperature at the die surface is higher than this critical temperature, the aluminum-rich phase is liquid and joins the die with the casting during the subsequent solidification. The paper discusses the mechanism of soldering for the case of pure aluminum and 380 alloy casting in a steel mold, the factors that promote soldering, and the strength of the bond formed when soldering occurs. conditions, an aluminum-rich soldering layer may also form over the intermetallic layer. Although a significant amount of research has been conducted on the nature of these intermetallics, little is known about the conditions under which soldering occurs.

  18. SLIP CASTING METHOD

    DOEpatents

    Allison, A.G.

    1959-09-01

    S>A process is described for preparing a magnesium oxide slip casting slurry which when used in conjunction with standard casting techniques results in a very strong "green" slip casting and a fired piece of very close dimensional tolerance. The process involves aging an aqueous magnestum oxide slurry, having a basic pH value, until it attains a specified critical viscosity at which time a deflocculating agent is added without upsetting the basic pH value.

  19. Mechanical properties and microstructure of centrifugally cast alloy 718

    SciTech Connect

    Michel, D.J.; Smith, H.H.

    1985-07-01

    The relationship between the microstructure and mechanical properties of alloy 718 was investigate for two discs centrifugally cast at 50 and 200 rpm and given a duplex age heat treatment. The results of mechanical property tests at temperatures from 426 to 649/sup 0/C showed that the tensile, yield and ultimate strength levels of both castings were similar. However, the creep-rupture properties were considerably enhanced for the casting produced at 200 rpm. Comparison of the radial and transverse creep properties of each disc indicated that creep life was generally independent of orientation, but ductility was greatest for specimens oriented transverse to the radial direction of the casting. Fatigue crack propagation performance was not greatly influenced by orientation or mold speed parameters and is comparable to wrought alloy 718 when compared on the basis of stress intensity factor range. The centrifugal casting process was found to produce a homogeneous microstructure free of porosity but with the expected segregation of solute alloying elements to Laves and carbide phases. The effect of the as-cast microstructure on the mechanical behavior and the potential influence of hot isostatic pressing to improve the microstructure are discussed.

  20. Mechanical properties and microstructure of centrifugally cast alloy 718

    NASA Astrophysics Data System (ADS)

    Michel, D. J.; Smith, H. H.

    1985-07-01

    The relationship between the microstructure and mechanical properties of alloy 718 was investigated for two discs centrifugally cast at 50 and 200 rpm and given a duplex age heat treatment. The results of mechanical property tests at temperatures from 426 to 649 °C showed that the tensile yield and ultimate strength levels of both castings were similar. However, the creep-rupture properties were considerably enhanced for the casting produced at 200 rpm. Comparison of the radial and transverse creep properties of each disc indicated that creep life was generally independent of orientation, but ductility was greatest for specimens oriented transverse to the radial direction of the casting. Fatigue crack propagation performance was not greatly influenced by orientation or mold speed parameters and was comparable to wrought alloy 718 when compared on the basis of stress intensity factor range. The centrifugal casting process was found to produce a homogeneous microstructure free of porosity but with the expected segregation of solute alloying elements to Laves and carbide phases. The effect of the as-cast microstructure on the mechanical behavior and the potential influence of hot isostatic pressing to improve the microstructure are discussed.

  1. Nonaqueous slip casting of YBa2Cu3O(7-x) superconductive ceramics. Ph.D. Thesis - 1993

    NASA Technical Reports Server (NTRS)

    Hooker, Matthew W.; Taylor, Theodore D.

    1994-01-01

    This study investigates the slip casting of YBa2Cu3O(7-x) powders using nonaqueous carrier liquids and fired ceramic molds. The parameters of the process examined here include the rheological properties of YBa2Cu3O(7-x) powder dispersed in various solvent/dispersant systems, the combination of nonaqueous slips with fired ceramic molds to form the superconductive ceramics, the process-property relationships using a four-factor factorial experiment, and the applicability of magnetic fields to align the YBa2Cu3O(7-x) grains during the casting process.

  2. Hot cracking during welding and casting

    NASA Astrophysics Data System (ADS)

    Cao, Guoping

    Aluminum welds are susceptible to liquation cracking in the partially melted zone (PMZ). Using the multicomponent Scheil model, curves of temperature vs. fraction solid (T-fS) during solidification were calculated for the PMZ and weld metals (WMs). These curves were used to predict the crack susceptibility by checking if the harmful condition of WM fS > PMZ fS exists during PMZ solidification and reduce the susceptibility by minimizing this condition. This approach was tested against full-penetration welds of alloys 7075 and 2024 and it can be used to guide the selection or development of filler metals. Liquation cracking in the PMZ in welds of Al-Si cast alloys was also investigated. The crack susceptibility was evaluated by circular-patch test, and full-penetration welds made with filler metals 1100, 4043, 4047 and 5356. Liquation cracking was significant with filler metals 1100 and 5356 but slight with filler metals 4043 and 4047. In all welds, liquation cracks were completely backfilled, instead of open as in full-penetration welds of wrought alloys 2219 and 6061. The T-fS curves showed that alloy A357 has a much higher fraction liquid for backfilling before PMZ solidification was essentially over. Hot tearing in Mg-xAl-yCa alloys was studied by constrained rod casting (CRC) in a steel mold. The hot tearing susceptibility decreased significantly with increasing Ca content (y) but did not change much with the Al content (x). An instrumented CRC with a steel mold was developed to detect the onset of hot tearing. The secondary phases, eutectic content, solidification path, and freezing range were examined. Hot tearing in Mg-Al-Sr alloys was also studied by CRC in a steel mold. With Mg-(4,6,8)Al-1.5Sr alloys, the hot tearing susceptibility decreased significantly with increasing Al content. With Mg-(4,6,8)Al-3Sr alloys, the trend was similar but not as significant. At the same Al content, the hot tearing susceptibility decreased significantly with increasing Sr

  3. Success in chess mediated by mental molds.

    PubMed

    Hernández Hernández, Pedro; Rodríguez Mateo, Heriberto

    2006-11-01

    Research has revealed the impact of cognitive-affective strategies (Molds of the Mind) on subjective well-being, interpersonal relationships, or school achievement. However, it seems odd that such strategies could influence the success of chess players, because this game is usually considered to be influenced mainly by technical and cognitive skills. To examine the influence of cognitive-affective molds, 53 chess players, ages from 9 to 16 years old, enrolled in sport competitions, were assigned to two groups, high and low success. They responded to the MOLDES, designed to evaluate individuals' molds. The results show that the "Mental Molds" of the most successful players are more realistic, positive and regulators of the emotions, while the molds of the less successful players are more evasive, magical, defensive and inoperative. PMID:17296106

  4. Amorphous materials molded IR lens progress report

    NASA Astrophysics Data System (ADS)

    Hilton, A. R., Sr.; McCord, James; Timm, Ronald; Le Blanc, R. A.

    2008-04-01

    Amorphous Materials began in 2000 a joint program with Lockheed Martin in Orlando to develop molding technology required to produce infrared lenses from chalcogenide glasses. Preliminary results were reported at this SPIE meeting by Amy Graham1 in 2003. The program ended in 2004. Since that time, AMI has concentrated on improving results from two low softening glasses, Amtir 4&5. Both glasses have been fully characterized and antireflection coatings have been developed for each. Lenses have been molded from both glasses, from Amtir 6 and from C1 Core glass. A Zygo unit is used to evaluate the results of each molded lens as a guide to improving the molding process. Expansion into a larger building has provided room for five production molding units. Molded lens sizes have ranged from 8 mm to 136 mm in diameter. Recent results will be presented

  5. Design and fabrication of cast orthopedic implants with freeform surface textures from 3-D printed ceramic shell.

    PubMed

    Curodeau, A; Sachs, E; Caldarise, S

    2000-09-01

    Three-dimensional printing is a solid freeform fabrication process, which creates parts directly from a computer model. The parts are built by repetitively spreading a layer of powder and selectively joining the powder in the layer by ink-jet printing of a binder material. 3D printing was applied to the fabrication of sub-millimeter surface textures with overhang and undercut geometries for use in orthopedic prostheses as bony ingrowth structures. 3D printing is used to fabricate ceramic molds of alumina powder and silica binder, and these molds are used to cast the bony ingrowth surfaces of Co-Cr (ASTM F75) alloy. Minimum positive feature sizes of the ceramic mold and, therefore, minimum negative feature sizes of castings were determined to be approximately 200 x 200 x 175 microm and were limited by the strength of ceramic needed to withstand handling. Minimum negative feature sizes in the ceramic mold and, therefore, minimum positive features in the casting were found to be approximately 350 x 350 x 175 microm and were determined by limitations on removal of powder from the ceramic and the pressure required to fill these small features with molten metal during casting. Textures were designed with 5 layers of distinct geometric definition, allowing for the design of overhung geometry with overall porosity ranging from 30-70%. Features as small as 350 x 350 x 200 microm were included in these designs and successfully cast. PMID:10984701

  6. Hydrogen silsesquioxane mold coatings for improved replication of nanopatterns by injection molding

    NASA Astrophysics Data System (ADS)

    Hobæk, Thor Christian; Matschuk, Maria; Kafka, Jan; Pranov, Henrik J.; Larsen, Niels B.

    2015-03-01

    We demonstrate the replication of nanosized pillars in polymer (cyclic olefin copolymer) by injection molding using nanostructured thermally cured hydrogen silsesquioxane (HSQ) ceramic coatings on stainless steel mold inserts with mold nanostructures produced by a simple embossing process. At isothermal mold conditions, the average pillar height increases by up to 100% and a more uniform height distribution is observed compared to a traditional metal mold insert. Thermal heat transfer simulations predict that the HSQ film retards the cooling of the polymer melt during the initial stages of replication, thus allowing more time to fill the nanoscale cavities compared to standard metal molds. A monolayer of a fluorinated silane (heptadecafluorotrichlorosilane) deposited on the mold surface reduces the mold/polymer interfacial energy to support demolding of the polymer replica. The mechanical stability of thermally cured HSQ makes it a promising material for nanopattern replication on an industrial scale without the need for slow and energy intensive variotherm processes.

  7. Mold in My School: What Do I Do?

    ERIC Educational Resources Information Center

    National Clearinghouse for Educational Facilities, Washington, DC.

    This publication provides information on the most important indoor mold-related health concerns and discusses how school districts can keep school facilities mold-free and avoid these problems. The document addresses when to be concerned, how molds cause health problems, symptoms caused by mold allergies, indoor molds that form toxins, who is most…

  8. Steel penetration in sand molds. Final technical report, September 1994--September 1997

    SciTech Connect

    Hayes, K.D.; Owens, M.; Barlow, J.; Stefanescu, D.M.; Lane, A.M.; Piwonka, T.S.

    1997-12-01

    The research program was successful in identifying the major factoirs that influence penetration. This was done first through a case study of penetration samples. The study revealed that both chemical and mechanical penetration were present in carbon and high manganese steels. It also found that only mechanical penetration is found in stainless steel samples. It should be noted that when mechanical penetration does occur, there is a greater risk of chemical reactions with the mold. Therefore, it is common to confuse mechanical penetration with chemical. Sessile drop experiments were run to discover the effect of steel chemistry on the contact angle for different substrates. These experiments revealed the best substrates for each type of metal. Bauxite, magnesite, and mullite were discovered to be the best materials for resisting mechanical penetration. It was also shown that high manganese steels cannot be poured into silica molds and that stainless steel should not be poured in chromite molds. The sessile drop data was used to develop a mechanical penetration model which correctly predicted penetration in sixteen of twenty castings poured at the University of Alabama. Mold/metal atmosphere tests were run to understand the effects of the atmosphere on chemical penetration. It was found that the chemistry affecting penetration has its greatest effect as the casting is just poured. Chemical penetration for low carbon steels cannot be completely eliminated by adding carbon (seacoal) to green sand molds although a marked decrease is obtained in its severity. Extremely high carbon concentrations might be able to totally eliminate the penetration but are not used because of their possible diffusion into the steel causing carburization. A chemical penetration model was produced and its results agree well with the experimental results.

  9. Casting Footprints for Eternity

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Apollo 11 Astronaut Buzz Aldrin has his footprints casted during the dedication ceremony of the rocket fountain at Building 4200 at Marshall Space Flight Center. The casts of Aldrin's footprints will be placed in the newly constructed Von Braun courtyard representing the accomplishments of the Apollo 11 lunar landing.

  10. Mold Cavity Roughness vs. Flow of Polymer

    NASA Astrophysics Data System (ADS)

    Stanek, Michal; Manas, Miroslav; Manas, David

    2009-07-01

    Injection molding represents such a way of polymer processing that requires injection of polymer melt into the mold cavity with very high injection rate. The fluidity of polymers is affected by many parameters (mold design, melt temperature, injection rate and pressure). The main objective of this paper is the study of influence of surface roughness of mold cavity of the polymer melts flow. Evaluation of set of data obtained by experiments where the testing conditions were widely changed shows that quality of cavity surface affects on the length of flow.

  11. Porous media heat transfer for injection molding

    DOEpatents

    Beer, Neil Reginald

    2016-05-31

    The cooling of injection molded plastic is targeted. Coolant flows into a porous medium disposed within an injection molding component via a porous medium inlet. The porous medium is thermally coupled to a mold cavity configured to receive injected liquid plastic. The porous medium beneficially allows for an increased rate of heat transfer from the injected liquid plastic to the coolant and provides additional structural support over a hollow cooling well. When the temperature of the injected liquid plastic falls below a solidifying temperature threshold, the molded component is ejected and collected.

  12. Mold Infections of the Central Nervous System

    PubMed Central

    McCarthy, Matthew; Rosengart, Axel; Schuetz, Audrey N.; Kontoyiannis, Dimitrios P.; Walsh, Thomas J.

    2016-01-01

    The recent outbreak of exserohilum rostratum meningitis linked to epidural injections of methylprednisolone acetate has brought renewed attention to mold infections of the central nervous system (CNS).1 Although uncommon, these infections are often devastating and difficult to treat. This focused review of the epidemiologic aspects, clinical characteristics, and treatment of mold infections of the CNS covers a group of common pathogens: aspergillus, fusarium, and scedosporium species, molds in the order Mucorales, and dematiaceous molds. Infections caused by these pathogen groups have distinctive epidemiologic profiles, clinical manifestations, microbiologic characteristics, and therapeutic implications, all of which clinicians should understand. PMID:25006721

  13. Indoor mold and Children's health

    PubMed

    Etzel; Rylander

    1999-06-01

    Reactive airways disease in children is increasing in many countries around the world. The clinical diagnosis of asthma or reactive airways disease includes a variable airflow and an increased sensitivity in the airways. This condition can develop after an augmented reaction to a specific agent (allergen) and may cause a life-threatening situation within a very short period of exposure. It can also develop after a long-term exposure to irritating agents that cause an inflammation in the airways in the absence of an allergen. (paragraph) Several environmental agents have been shown to be associated with the increased incidence of childhood asthma. They include allergens, cat dander, outdoor as well as indoor air pollution, cooking fumes, and infections. There is, however, increasing evidence that mold growth indoors in damp buildings is an important risk factor. About 30 investigations from various countries around the world have demonstrated a close relationship between living in damp homes or homes with mold growth, and the extent of adverse respiratory symptoms in children. Some studies show a relation between dampness/mold and objective measures of lung function. Apart from airways symptoms, some studies demonstrate the presence of general symptoms that include fatigue and headache and symptoms from the central nervous system. At excessive exposures, an increased risk for hemorraghic pneumonia and death among infants has been reported. (paragraph) The described effects may have important consequences for children in the early years of life. A child's immune system is developing from birth to adolescence and requires a natural, physiologic stimulation with antigens as well as inflammatory agents. Any disturbances of this normal maturing process will increase the risk for abnormal reactions to inhaled antigens and inflammagenic agents in the environment. (paragraph) The knowledge about health risks due to mold exposure is not widespread and health authorities in

  14. FInal Report - Investment Casting Shell Cracking

    SciTech Connect

    Von Richards

    2003-12-01

    This project made a significant contribution to the understanding of the investment casting shell cracking problem. The effects of wax properties on the occurrence of shell cracking were demonstrated and can be measured. The properties measured include coefficient of thermal expansion, heating rate and crystallinity of the structure. The important features of production molds and materials properties have been indicated by case study analysis and fractography of low strength test bars. It was found that stress risers in shell cavity design were important and that typical critical flaws were either oversize particles or large pores just behind the prime coat. It was also found that the true effect of fugitive polymer fibers was not permeability increase, but rather a toughening mechanism due to crack deflection.

  15. 40 CFR Table 1 to Subpart Wwww of... - Equations To Calculate Organic HAP Emissions Factors for Specific Open Molding and Centrifugal...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Equations To Calculate Organic HAP Emissions Factors for Specific Open Molding and Centrifugal Casting Process Streams 1 Table 1 to Subpart WWWW of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS...

  16. Use of acrylic sheet molds for elastomeric products

    NASA Technical Reports Server (NTRS)

    Heisman, R. M.; Koerner, A. E.; Messineo, S. M.

    1970-01-01

    Molds constructed of acrylic sheet are more easily machined than metal, are transparent to ensure complete filling during injection, and have smooth surfaces free of contamination. Technique eliminates flashing on molded parts and mold release agents.

  17. 1. INTERIOR VIEW OF MOLDING ROOM, NO. 2 WORKS, SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. INTERIOR VIEW OF MOLDING ROOM, NO. 2 WORKS, SHOWING BUCKET LINE FEEDING MOLDING MACHINES - Harbison-Walker Refractories Company, Molding Room, West end of Shirley Street, Mount Union, Huntingdon County, PA

  18. Commercial and Residential Water Damage: The Mold Connection.

    ERIC Educational Resources Information Center

    Williams, Del

    2002-01-01

    Describes the problem of toxic mold in residential and commercial property resulting from excess moisture. Includes common sources of unwanted moisture, design and construction flaws, determining the presence of mold, and advice for identifying and hiring reputable mold remediators. (PKP)

  19. Mold

    MedlinePlus

    ... Clin Immunol 130(1):267–270. 12 Chulada PC, Kennedy S, Mvula MM, Jaffee K, Wildfire J, Thornton ... 120(11): 1592–1599. 13 Grimsley LF, Chulada PC, Kennedy S, White L, Wildfire J, Cohn RD, Mitchell ...

  20. INTERIOR VIEW WITH LARGE PIPE CASTING MACHINE CASTING A 48' ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW WITH LARGE PIPE CASTING MACHINE CASTING A 48' PIPE OPERATOR SPRAYING A POWDER TO HELP SOLIDIFY THE PIPE BEING CENTRIFUGALLY CAST. - United States Pipe & Foundry Company Plant, Pipe Casting & Testing Area, 2023 St. Louis Avenue at I-20/59, Bessemer, Jefferson County, AL

  1. Casting in Sport

    PubMed Central

    DeCarlo, Mark; Malone, Kathy; Darmelio, John; Rettig, Arthur

    1994-01-01

    Attempts by sports medicine professionals to return high school athletes with hand and wrist injuries to competition quickly and safely have been the source of confusion and debate on many playing fields around the country. In addition to the differing views regarding the appropriateness of playing cast usage in high school football, a debate exists among sports medicine professionals as to which material is best suited for playing cast construction. Materials used in playing cast construction should be hard enough to provide sufficient stabilization to the injured area and include adequate padding to absorb blunt impact forces. The purpose of the biomechanical portion of this investigation was to attempt to determine the most appropriate materials for use in constructing playing casts for the hand and wrist by assessing different materials for: 1) hardness using a Shore durometer, and 2) ability to absorb impact using a force platform. Results revealed that RTV11 and Scotchcast were the “least hard” of the underlying casting materials and that Temper Stick foam greatly increased the ability of RTV11 to absorb impact. Assessment of the mechanical properties of playing cast materials and review of current developments in high school football rules are used to aid practitioners in choosing the most appropriate materials for playing cast construction. ImagesFig 1.Fig 2.Fig 3. PMID:16558257

  2. Commercialization effort in support of electroslag-casting technology

    SciTech Connect

    Sikka, V.K.

    1993-06-01

    This report summarizes the results of an effort to revive interest in the electroslag casting (ESC) of components in the United States. The ESC process is an extension of a well established electroslag-remelting (ESR) process. Both processes use the electrode of a material that is continuously melted and cast in a water-cooled copper mold. For simple shapes, the mold can be movable, allowing the continuous casting of long lengths. In an effort to revive US industries` interest in ESC, the following approaches were taken: (1) US industries with prior experience in ESC or currently operating an ESR unit were contacted, followed up with telephone conversation, and/or sent copies of prior published reports on the topic, and, in some cases, personal visits were made; (2) with two companies, a potential interest in ESC was worked out by initially conducting ESR; and (3) to further strengthen the industrial interest, the newly developed iron-aluminide alloy, FA-129, was chosen as the material of choice for this study. The two industrial companies that worked with ORNL were Special Metals Corporation (New Hartford, New York) and Precision Rolled Products, Inc. (PRP) [Florham Park, New Jersey]. Even with its advantages, a survey of the industry indicated that ESC technology has a very limited chance of advancement in the United States. However, the processing of rounds and slabs by the ESR process is a well established commercial technology and will continue to expand. 16 figs, 3 tabs, 12 refs.

  3. Transient Thermo-fluid Model of Meniscus Behavior and Slag Consumption in Steel Continuous Casting

    NASA Astrophysics Data System (ADS)

    Jonayat, A. S. M.; Thomas, Brian G.

    2014-10-01

    The behavior of the slag layer between the oscillating mold wall, the slag rim, the slag/liquid steel interface, and the solidifying steel shell, is of immense importance for the surface quality of continuous-cast steel. A computational model of the meniscus region has been developed, that includes transient heat transfer, multi-phase fluid flow, solidification of the slag, and movement of the mold during an oscillation cycle. First, the model is applied to a lab experiment done with a "mold simulator" to verify the transient temperature-field predictions. Next, the model is verified by matching with available literature and plant measurements of slag consumption. A reasonable agreement has been observed for both temperature and flow-field. The predictions show that transient temperature behavior depends on the location of the thermocouple during the oscillation relative to the meniscus. During an oscillation cycle, heat transfer variations in a laboratory frame of reference are more severe than experienced by the moving mold thermocouples, and the local heat transfer rate is increased greatly when steel overflows the meniscus. Finally, the model is applied to conduct a parametric study on the effect of casting speed, stroke, frequency, and modification ratio on slag consumption. Slag consumption per unit area increases with increase of stroke and modification ratio, and decreases with increase of casting speed while the relation with frequency is not straightforward. The match between model predictions and literature trends suggests that this methodology can be used for further investigations.

  4. Determination of Bulk Dimensional Variation in Castings

    SciTech Connect

    Dr. James F. Cuttino Dr. Edward P. Morse

    2005-04-14

    The purpose of this work is to improve the efficiency of green sand foundries so that they may continue to compete as the most cost-effective method of fabrication while meeting tightening constraints on near-net shape manufacturing. In order to achieve this objective, the study is divided into two major components. The first component concentrated on identifying which processes control surface finish on the castings and which provide potential reductions in variations. The second component identified metrological methods that effectively discern between the geometry of bulk material versus surface finish in order to more accurately determine the quality of a part. The research resulted in the determination of an empirical relationship relating pouring parameters to dimensional variation, with an R2 value of greater than 0.79. A significant difference in variations obtained from vertical vs. horizontal molding machines was also noticed. When analyzed separately, however, the resulting empirical relationships for horizontal and vertical machines had reduced R2 values, probably due to the reduced data sets. Significant parameters when considering vertical and horizontal molding machines together included surface roughness, pattern type, iron type, pouring rate, copper content, amount of Western Bentonite, and permeability.

  5. Mold Remediation in Schools and Commercial Buildings.

    ERIC Educational Resources Information Center

    Environmental Protection Agency, Washington, DC. Office of Radiation and Indoor Air.

    This document describes how to investigate and evaluate moisture and mold problems in educational facilities, and presents the key steps for implementing a remediation plan. A checklist is provided for conducting mold remediation efforts along with a resource list of helpful organizations and governmental agencies. Appendices contain a glossary,…

  6. Particle Image Velocimetry During Injection Molding

    NASA Astrophysics Data System (ADS)

    Bress, Thomas; Dowling, David

    2012-11-01

    Injection molding involves the unsteady non-isothermal flow of a non-Newtonian polymer melt. An optical-access mold has been used to perform particle image velocimetry (PIV) on molten polystyrene during injection molding. Velocimetry data of the mold-filling flow will be presented. Statistical assessments of the velocimetry data and scaled residuals of the continuity equation suggest that PIV can be conducted in molten plastics with an uncertainty of +/-2 percent. Simulations are often used to model polymer flow during injection molding to design molds and select processing parameters but it is difficult to determine the accuracy of these simulations due to a lack of in-mold velocimetry and melt-front progression data. Moldflow was used to simulate the filling of the optical-access mold, and these simulated results are compared to the appropriately-averaged time-varying velocity field measurements. Simulated results for melt-front progression are also compared with the experimentally observed flow fronts. The ratio of the experimentally measured average velocity magnitudes to the simulation magnitudes was found on average to be 0.99 with a standard deviation of 0.25, and the difference in velocity orientations was found to be 0.9 degree with a standard deviation of 3.2 degrees. formerly at the University of Michigan.

  7. EXPOSURE OF CHILDREN TO INDOOR MOLDS

    EPA Science Inventory

    Children now spend more than 90% of their time indoors. Thus, any exposure to indoor pollutants may be critical to their health. Molds are one of the most important pollutants children are exposed to indoors. Molds produce hundreds of allergens and toxins. These products ha...

  8. Dynamic Feed Control For Injection Molding

    DOEpatents

    Kazmer, David O.

    1996-09-17

    The invention provides methods and apparatus in which mold material flows through a gate into a mold cavity that defines the shape of a desired part. An adjustable valve is provided that is operable to change dynamically the effective size of the gate to control the flow of mold material through the gate. The valve is adjustable while the mold material is flowing through the gate into the mold cavity. A sensor is provided for sensing a process condition while the part is being molded. During molding, the valve is adjusted based at least in part on information from the sensor. In the preferred embodiment, the adjustable valve is controlled by a digital computer, which includes circuitry for acquiring data from the sensor, processing circuitry for computing a desired position of the valve based on the data from the sensor and a control data file containing target process conditions, and control circuitry for generating signals to control a valve driver to adjust the position of the valve. More complex embodiments include a plurality of gates, sensors, and controllable valves. Each valve is individually controllable so that process conditions corresponding to each gate can be adjusted independently. This allows for great flexibility in the control of injection molding to produce complex, high-quality parts.

  9. 21ST CENTURY MOLD ANALYSIS IN FOOD

    EPA Science Inventory

    Traditionally, the indoor air community has relied on mold analysis performed by either microscopic observations or the culturing of molds on various media to assess indoor air quality. These techniques were developed in the 19th century and are very laborious and time consumin...

  10. Energy Saving Melting and Revert Reduction (E-SMARRT): Precision Casting of Steel

    SciTech Connect

    Dr. Von L. Richards

    2011-09-30

    This project addresses improvements in metal casting processes by reducing scrap and reducing the cost of production, due to scrap reduction from investment casting and yield improvement offered by lost foam casting as compared to no-bake or green sand molding. The objectives for the investment casting portion of the subtask are to improve knowledge of fracture toughness of mold shells and the sources of strength limiting flaws and to understand the effects of wax reclamation procedures on wax properties. Applying 'clean steel' approaches to pouring technology and cleanliness in investment casting of steel are anticipated to improve incoming materials inspection procedures as they affect the microstructure and toughness of the shell. This project focused on two areas of study in the production of steel castings to reduce scrap and save energy: (1) Reducing the amount of shell cracking in investment cast steel production; (2) Investigate the potential of lost foam steel casting The basic findings regarding investment casting shell cracking were: (1) In the case of post pouring cracking, this could be related to phase changes in silica upon cooling and could be delayed by pouring arrangement strategies that maintained the shell surface at temperature for longer time. Employing this delay resulted in less adherent oxidation of castings since the casting was cooler at the time o fair exposure. (2) A model for heat transfer through water saturated shell materials under steam pressure was developed. (3) Initial modeling result of autoclave de-waxing indicated the higher pressure and temperature in the autoclave would impose a steeper temperature gradient on the wax pattern, causing some melt flow prior to bulk expansion and decreasing the stress on the green shell. Basic findings regarding lost foam casting of steel at atmospheric pressure: (1) EPS foam generally decomposes by the collapse mode in steel casting. (2) There is an accumulation of carbon pick-up at the end

  11. Fastcast: Integration and application of rapid prototyping and computational simulation to investment casting

    SciTech Connect

    Maguire, M.C.; Baldwin, M.D.; Atwood, C.L.

    1996-09-01

    The emergence of several rapid prototyping and manufacturing (RP and M) technologies is having a dramatic impact on investment casting. While the most successful of the rapid prototyping technologies are almost a decade old, relatively recent process advances in their application have produced some remarkable success in utilizing their products as patterns for investment castings. Sandia National Laboratories has been developed highly coupled experimental and computational capabilities to examine the investment casting process with the intention of reducing the amount of time required to manufacture castings, and to increase the quality of the finished product. This presentation will begin with process aspects of RP and M pattern production and handling, shell fabrication, burnout, and casting. The emphasis will be on how the use of Stereolithography (SL) or Selective Laser Sintered (SLS) patterns differs from more traditional wax pattern processes. Aspects of computational simulation to couple design, thermal analysis, and mold filling will be discussed. Integration of these topics is probably the greatest challenge to the use of concurrent engineering principles with investment casting. Sandia has conducted several experiments aimed at calibrating computer codes and providing data for input into these simulations. Studies involving materials as diverse as stainless steel and gold have been conducted to determine liquid metal behavior in molds via real time radiography. The application of these experiments to predictive simulations will be described.

  12. Strong, easy-to-mold, spiral buttress thread

    NASA Technical Reports Server (NTRS)

    Heier, W. C.

    1971-01-01

    Buttress thread with steep taper connects two molded plastic cylinders without changing wall thickness or sacrificing longitudinal strength at the juncture. Technique lends itself to conventional molding methods.

  13. IC chip stress during plastic package molding

    SciTech Connect

    Palmer, D.W.; Benson, D.A.; Peterson, D.W.; Sweet, J.N.

    1998-02-01

    Approximately 95% of the world`s integrated chips are packaged using a hot, high pressure transfer molding process. The stress created by the flow of silica powder loaded epoxy can displace the fine bonding wires and can even distort the metalization patterns under the protective chip passivation layer. In this study the authors developed a technique to measure the mechanical stress over the surface of an integrated circuit during the molding process. A CMOS test chip with 25 diffused resistor stress sensors was applied to a commercial lead frame. Both compression and shear stresses were measured at all 25 locations on the surface of the chip every 50 milliseconds during molding. These measurements have a fine time and stress resolution which should allow comparison with computer simulation of the molding process, thus allowing optimization of both the manufacturing process and mold geometry.

  14. 40 CFR Table 3 to Subpart Wwww of... - Organic HAP Emissions Limits for Existing Open Molding Sources, New Open Molding Sources Emitting...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... mold is vented during spinning and cureb. resin application with the mold closed, and the mold is not vented during spinning and cure c. resin application with the mold open, and the mold is vented during spinning and cure d. resin application with the mold open, and the mold is not vented during spinning...

  15. 40 CFR Table 3 to Subpart Wwww of... - Organic HAP Emissions Limits for Existing Open Molding Sources, New Open Molding Sources Emitting...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... closed, and the mold is vented during spinning and cureb. resin application with the mold closed, and the mold is not vented during spinning and cure c. resin application with the mold open, and the mold is vented during spinning and cure d. resin application with the mold open, and the mold is not...

  16. 40 CFR Table 3 to Subpart Wwww of... - Organic HAP Emissions Limits for Existing Open Molding Sources, New Open Molding Sources Emitting...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... closed, and the mold is vented during spinning and cureb. resin application with the mold closed, and the mold is not vented during spinning and cure c. resin application with the mold open, and the mold is vented during spinning and cure d. resin application with the mold open, and the mold is not...

  17. 40 CFR Table 3 to Subpart Wwww of... - Organic HAP Emissions Limits for Existing Open Molding Sources, New Open Molding Sources Emitting...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... mold is vented during spinning and cureb. resin application with the mold closed, and the mold is not vented during spinning and cure c. resin application with the mold open, and the mold is vented during spinning and cure d. resin application with the mold open, and the mold is not vented during spinning...

  18. Casting Characteristics of Aluminum Die Casting Alloys

    SciTech Connect

    Makhlouf M. Makhlouf; Diran Apelian

    2002-02-05

    The research program investigates the casting characteristics of selected aluminum die casting alloys. Specifically, the alloys' tendencies towards die soldering and sludge formation, and the alloys' fluidity and machinability are evaluated. It was found that: When the Fe and Mn contents of the alloy are low; caution has to be taken against possible die soldering. When the alloy has a high sludge factor, particularly a high level of Fe, measures must be taken to prevent the formation of large hardspots. For this kind of alloy, the Fe content should be kept at its lowest allowable level and the Mn content should be at its highest possible level. If there are problems in die filling, measures other than changing the alloy chemistry need to be considered first. In terms of alloy chemistry, the elements that form high temperature compounds must be kept at their lowest allowable levels. The alloys should not have machining problems when appropriate machining techniques and machining parameters are used.

  19. Three-dimensional ceramic molding process based on microstereolithography for the production of piezoelectric energy harvesters

    NASA Astrophysics Data System (ADS)

    Maruo, Shoji; Sugiyama, Kenji; Daicho, Yuya; Monri, Kensaku

    2014-03-01

    A three-dimensional (3-D) molding process using a master polymer mold produced by microstereolithography has been developed for the production of piezoelectric ceramic elements. In this method, ceramic slurry is injected into a 3-D polymer mold via a centrifugal casting process. The polymer master mold is thermally decomposed so that complex 3-D piezoelectric ceramic elements can be produced. As an example of 3-D piezoelectric ceramic elements, we produced a spiral piezoelectric element that can convert multidirectional loads into a voltage. It was confirmed that a prototype of the spiral piezoelectric element could generate a voltage by applying a load in both parallel and lateral directions in relation to the helical axis. The power output of 123 pW was obtained by applying the maximum load of 2.8N at 2 Hz along the helical axis. In addition, to improve the performance of power generation, we utilized a two-step sintering process to obtain dense piezoelectric elements. As a result, we obtained a sintering body with relative density of 92.8%. Piezoelectric constant d31 of the sintered body attained to -40.0 pC/N. Furthermore we analyzed the open-circuit voltage of the spiral piezoelectric element using COMSOL multiphysics. As a result, it was found that use of patterned electrodes according to the surface potential distribution of the spiral piezoelectric element had a potential to provide high output voltage that was 20 times larger than that of uniform electrodes.

  20. (Continuous casting 1985)

    SciTech Connect

    Wilde, R.A.

    1985-06-12

    The report covers the Continuous Casting '85 Conference including informal discussions with conference attendees. In general, the papers presented at the conference concerned an overview of continuous steel casting worldwide, state-of-the-art aspects of steel continuous casting technology including caster startup problems, modifications, control system strategies, energy use profiles, quality control aspects, steel chemistry control, refractories, operational aspects of continuous casters, etc. No papers were presented in the development of thin section or thin strip casting of steel. Informal discussions were held with several conference attendees including (1) Bernard Trentini, Executive Director of the Association Technique De La Siderurgie Francaise in Paris, France (similar to the American Iron and Steel Institute); (2) Dr. Wolfgang Reichelt and Dr. Peter Voss-Spilker both of Mannesmann Demag Huttentechnik -a continuous casting and other steel making machine builder in-lieu of meeting at their plant in Duisburg, FRG on May 31; (3) Ewan C. Hewitt of Devote McKee Corp., Sheffield, England; (4) Wilfried Heinemann, head of R D Dept. at Concast Standard AG in Zurich, Switzerland; and (5) Hideo Ueno, engineer of melting section, Mitsubishi Steel Mfg. Co. Ltd, Tokyo Japan. A visit was made to the Teesside Laboratories of British Steel Corp. for discussions of their thin section casting research program in particular and R D program in general.

  1. Salvaged castings and methods of salvaging castings with defective cast cooling bumps

    DOEpatents

    Johnson, Robert Alan; Schaeffer, Jon Conrad; Lee, Ching-Pang; Abuaf, Nesim; Hasz, Wayne Charles

    2002-01-01

    Castings for gas turbine parts exposed on one side to a high-temperature fluid medium have cast-in bumps on an opposite cooling surface side to enhance heat transfer. Areas on the cooling surface having defectively cast bumps, i.e., missing or partially formed bumps during casting, are coated with a braze alloy and cooling enhancement material to salvage the part.

  2. The Influence of Na2O on the Solidification and Crystallization Behavior of CaO-SiO2-Al2O3-Based Mold Flux

    NASA Astrophysics Data System (ADS)

    Gao, Jinxing; Wen, Guanghua; Sun, Qihao; Tang, Ping; Liu, Qiang

    2015-08-01

    The reaction between [Al] and SiO2 sharply increased the Al2O3 and decreased SiO2 contents in mold flux during the continuous casting of high-Al steels. These changes converted original CaO-SiO2-based flux into CaO-SiO2-Al2O3-based flux, promoting the crystallization and deteriorating the mold lubrication. Therefore, study on the solidification and crystallization behavior of CaO-SiO2-Al2O3-based mold flux, with the applicable fluidizers, is of importance. The effect of Na2O, predominantly used as the fluidizer in mold flux, on the solidification and crystallization behavior of CaO-SiO2-Al2O3-based mold flux needs to be investigated. In this study, a CaO-SiO2-Al2O3-based mold flux containing 6.5 wt pct Li2O was designed; the effect of Na2O on the solidification and crystallization behavior of these mold fluxes was investigated using the single hot thermocouple technique (SHTT) and the double hot thermocouple technique (DHTT). Moreover, the slag film obtained by a heat flux simulator was analyzed using X-ray diffraction (XRD). The results indicate that the solid fraction of molten slag (Fs) and the crystalline fraction of solid slag (Fc) in the mold slag films decrease with increasing Na2O content from 0 to 2 wt pct. However, Fs and Fc increased when the Na2O content increased from 2 to 6 wt pct. The critical cooling rates initially decreases and then increases with increasing Na2O content. The XRD analysis results show that LiAlO2 and CaF2 were the basic crystals for all the mold fluxes. Increasing the Na2O content both inhibits the Ca2Al2SiO7 formation and promotes the production of Ca12Al14O33, indicating that the mold lubrication deteriorated because of the high melting-point phase formation of Ca2Al2SiO7 in the CaO-SiO2-Al2O3-based mold flux containing 6.5 wt pct Li2O, without Na2O. The strong crystallization tendency also deteriorated the mold lubrication for the mold flux with a higher Na2O content. Therefore, the addition of Na2O was less than 2 wt pct in

  3. Preparation of Microstructure Molds of Montmorillonite/Polyethylene Glycol Diacrylate and Multi-Walled Carbon Nanotube/Polyethylene Glycol Diacrylate Nanocomposites for Miniaturized Device Applications.

    PubMed

    Kim, Young Ho; Sohn, Jeong-Woo; Woo, Youngjae; Hong, Joo-Hyun; Kim, Gyu Man; Kang, Bong Keun; Park, Juyoung

    2015-10-01

    Environmentally friendly microstructure molds with montmorillonite (MMT) or multi-walled carbon nanotube (MWCNT) reinforced polyethylene glycol diacrylate (PEGDA) nanocomposites have been prepared for miniaturized device applications. The micropatterning of MMT/PEGDA and MWCNT/PEGDA with 0.5 to 2.0 wt% of MMTs and MWCNTs was achieved through a UV curing process with micro-patterned masks. Hexagonal dot arrays and complex patterns for microstructures of the nanocomposites were produced and characterized with an optical microscope; their thermal properties were studied by thermogravimetric analysis (TGA). The TGA results showed that these nanocomposites were thermally stable up to 350 °C. Polydimethylsiloxane thin replicas with different microstructures were prepared by a casting method using the microstructured nanocomposites as molds. It is considered that these microstructure molds of the nanocomposites can be used as microchip molds to fabricate nanobio-chips and medical diagnostic chip devices. PMID:26726429

  4. Inoculated Slightly Hypereutectic Gray Cast Irons

    NASA Astrophysics Data System (ADS)

    Chisamera, Mihai; Riposan, Iulian; Stan, Stelian; Militaru, Cristina; Anton, Irina; Barstow, Michael

    2012-03-01

    The current experimental investigation in this article was designed to characterize the structure of mold (M) and ladle (L) inoculated, low-S (0.025 wt.% S), low-Al (0.003 wt.% Al), slightly hypereutectic (CE = 4.4-4.5 wt.%) electric melted gray irons, typical for high performance thin-wall castings. It describes the effect of a Ca, Al, Zr-FeSi inoculant addition of 0-0.25 wt.% on structure characteristics, and compares to similar treatments with hypoeutectic irons (3.5-3.6 wt.% CE, 0.025 wt.% S, and 0.003 wt.% Al). A complex structure including primary graphite, austenite dendrites, and eutectic cells is obtained in hypereutectic irons, as the result of nonequilibrium solidification following the concept of a coexisting region. Dendrites appear to be distributed between eutectic cells at higher eutectic undercooling, while in inoculated irons and for lower undercooling, the eutectic cells are "reinforced" by eutectic austenite dendrites. A Zr, Ca, Al-FeSi alloy appears to be an effective inoculant in low S, low Al, gray cast irons, especially for a late inoculation technique, with beneficial effects on both graphite and austenite phases. First, inoculation influenced the nucleation of graphite/eutectic cell, and then their characteristics. A further role of these active elements directly contributed to form nucleation sites for austenite, as complex (Mn,X)S particles.

  5. Characterization of fiberglass-filled diallyl phthalate plastic molding resins and molded parts

    SciTech Connect

    Whitaker, R.B.; Glaub, J.E.; Bonekowski, N.R.; Gillham, P.D.

    1980-12-01

    Characterization of diallyl phthalate (DAP) molding resins was undertaken by differential scanning calorimetry (DSC) and by combined size exclusion chromatography (SEC)/low angle laser light scattering (LALLS) in order to better predict moldability and storage life limits. Completeness of cure of molded parts, before and after any post-curing, was also determined by thermal analysis. Molecular weights and molecular weight distributions of the DAP molding resins by SEC/LALLS indicated that the better molding resins have lower M/sub w//M/sub n/ ratios. Association effects were observed, which could not be overcome by solvent modification alone. Determination of DAP molding resin heats of reaction by DSC indicated a linear relation between ..delta..H/sub R/ and weight percent filler for the good molding resins. DSC analyses of molded DAP parts showed that 95% cure was achieved in some as-molded parts, with a post-cure temperature of 165/sup 0/C being required to complete the cure to 100%. Thickness of the parts was a factor, with the thicker parts being 100% cured as molded. The glass transition temperature (T/sub g/) of the molded parts increased as cure was completed, to approx. 160 to 165/sup 0/C maximum. These results are consistent with a model of thermoset resin curing behavior which states that 100% cure can be achieved only if a post-curing operation is conducted above the T/sub g infinity/ (T/sub g/ at complete cure) of the polymer.

  6. Monolithic multilayer microfluidics via sacrificial molding of 3D-printed isomalt†

    PubMed Central

    Gelber, Matthew K.

    2015-01-01

    Here we demonstrate a method for creating multilayer or 3D microfluidics by casting a curable resin around a water-soluble, freestanding sacrificial mold. We use a purpose-built 3D printer to pattern self-supporting filaments of the sugar alcohol isomalt, which we then back-fill with a transparent epoxy resin. Dissolving the sacrificial mold leaves a network of cylindrical channels as well as input and output ports. We use this technique to fabricate a combinatorial mixer capable of producing 8 combinations of two fluids in ratios ranging from 1 : 100 to 100 : 1. This approach allows rapid iteration on microfluidic chip design and enables the use of geometry and materials not accessible using conventional soft lithography. The ability to precisely pattern round channels in all three dimensions in hard and soft media may prove enabling for many organ-on-chip systems. PMID:25671493

  7. Thermal stresses in chemically hardening elastic media with application to the molding process

    NASA Technical Reports Server (NTRS)

    Levitsky, M.; Shaffer, B. W.

    1974-01-01

    A method has been formulated for the determination of thermal stresses in materials which harden in the presence of an exothermic chemical reaction. Hardening is described by the transformation of the material from an inviscid liquid-like state into an elastic solid, where intermediate states consist of a mixture of the two, in a ratio which is determined by the degree of chemical reaction. The method is illustrated in terms of an infinite slab cast between two rigid mold surfaces. It is found that the stress component normal to the slab surfaces vanishes in the residual state, so that removal of the slab from the mold leaves the remaining residual stress unchanged. On the other hand, the residual stress component parallel to the slab surfaces does not vanish. Its distribution is described as a function of the parameters of the hardening process.

  8. Monolithic multilayer microfluidics via sacrificial molding of 3D-printed isomalt.

    PubMed

    Gelber, Matthew K; Bhargava, Rohit

    2015-04-01

    Here we demonstrate a method for creating multilayer or 3D microfluidics by casting a curable resin around a water-soluble, freestanding sacrificial mold. We use a purpose-built 3D printer to pattern self-supporting filaments of the sugar alcohol isomalt, which we then back-fill with a transparent epoxy resin. Dissolving the sacrificial mold leaves a network of cylindrical channels as well as input and output ports. We use this technique to fabricate a combinatorial mixer capable of producing 8 combinations of two fluids in ratios ranging from 1 : 100 to 100 : 1. This approach allows rapid iteration on microfluidic chip design and enables the use of geometry and materials not accessible using conventional soft lithography. The ability to precisely pattern round channels in all three dimensions in hard and soft media may prove enabling for many organ-on-chip systems. PMID:25671493

  9. Study on heat flux from resin to mold in injection molding process

    SciTech Connect

    Nishiwaki, Nobuhiko; Hori, Sankei

    1999-07-01

    Recently, an injection molding of thermoplastic is widely used in many industries, because this manufacturing method is very suitable for mass production. For injection molding processes, a number of software packages for simulating an injection molding process have been developed. It is assumed in these software packages that the heat transfer coefficient between the resin and the mold surface is constant at the filling or cooling stages. In general, when melted resin flows into the mold, heat is generated in the flowing resin because of the high viscosity at the filling stage. Moreover at the cooling stage, a separation of the molded part from the mold surface generally occurs because of shrinkage of the molded material. Therefore, the heat transfer coefficient has not been accurately obtained yet at these stages. In this paper, the temperature near the surface of the mold cavity has been experimentally measured, so the heat flux that flows from the resin to the mold has been able to be analytically estimated by an inverse conduction method. On the other hand, the separating behavior of the resin from the mold surface has been measured using an ultrasonic transducer attached to the outer surface of the stationary mold. The heat flux that flows from the resin to the mold has been analytically estimated. The apparent heat transfer coefficient can be obtained from the heat flux and the representative temperature difference, which is measured by an ultrasonic technique. It was discovered that the heat flux and the apparent heat transfer coefficient are hardly influenced by the separation.

  10. Assessment of the State of Precipitation in Aluminum Casting A356.2 Alloy Using Nondestructive Microstructure Electronic Property Measurements

    NASA Astrophysics Data System (ADS)

    Kiattisaksri, P.; Gibbs, P. J.; Koenig, K.; Pfeif, E. A.; Lasseigne, A. N.; Mendez, P. F.; Mishra, B.; Olson, D. L.

    2010-02-01

    Application of nondestructive electronic property measurements to assess the strengthening of Mg2Si precipitates in aluminum A356.2 casting has been demonstrated. The results indicated the evolution of precipitation phase through over aging with increased cooling time or thickness of the cast part. The classical optimum precipitation behavior has been characterized and verified with thermal analysis, thermoelectric power, low frequency impedance, and micro hardness measurements. A proposed practice to use nondestructive electronic property measurement tools to assess aluminum casting for acceptable mechanical properties after mold shake out is presented.

  11. Filler metal alloy for welding cast nickel aluminide alloys

    DOEpatents

    Santella, Michael L.; Sikka, Vinod K.

    1998-01-01

    A filler metal alloy used as a filler for welding east nickel aluminide alloys contains from about 15 to about 17 wt. % chromium, from about 4 to about 5 wt. % aluminum, equal to or less than about 1.5 wt. % molybdenum, from about 1 to about 4.5 wt. % zirconium, equal to or less than about 0.01 wt. % yttrium, equal to or less than about 0.01 wt. % boron and the balance nickel. The filler metal alloy is made by melting and casting techniques such as are melting the components of the filler metal alloy and east in copper chill molds.

  12. Steel castings by the electroslag casting technique. [CF8M

    SciTech Connect

    Sikka, V.K.; Mitchell, A.

    1984-01-01

    ELectroslag casting facilities in Canada and the United States were reviewed. Several valve body castings of 2-1/4 Cr-1 Mo, 9 Cr-1 Mo, and 18% Cr-8% Ni(Mo) steels were made at the University of British Columbia facility. These castings were examined for surface finish, chemical segregation, and macrostructure in the as-cast condition and after various heat treatments. Castings were subjected to tensile, Charpy impact, and creep testing. Results of these tests were compared with similar data on wrought material and sand castings.

  13. Residual stresses in injection molded products

    NASA Astrophysics Data System (ADS)

    Jansen, K. M. B.

    2015-12-01

    During the molding process residual stresses are formed due to thermal contraction during cooling as well as the local pressure history during solidification. In this paper a simple analytical model is reviewed which relates residual stresses, product shrinkage as well as warpage to the temperature and pressure histories during molding. Precise excimer laser layer removal measurements were performed to verify the predicted residual stress distributions. In addition, detailed shrinkage and warpage measurements on a large series of polymers and for different molding conditions were performed and are shown to compare well with the model predictions.

  14. Slimeware: engineering devices with slime mold.

    PubMed

    Adamatzky, Andrew

    2013-01-01

    The plasmodium of the acellular slime mold Physarum polycephalum is a gigantic single cell visible to the unaided eye. The cell shows a rich spectrum of behavioral patterns in response to environmental conditions. In a series of simple experiments we demonstrate how to make computing, sensing, and actuating devices from the slime mold. We show how to program living slime mold machines by configurations of repelling and attracting gradients and demonstrate the workability of the living machines on tasks of computational geometry, logic, and arithmetic. PMID:23834592

  15. Mucormycosis, Pseudallescheriasis, and Other Uncommon Mold Infections

    PubMed Central

    Quan, Clifford; Spellberg, Brad

    2010-01-01

    Serious infections due to non-Aspergillus molds are being encountered with increasing frequency. Factors likely responsible for the rise of these infections include aging populations in countries with advanced medical technologies, the resultant increase in incidence of many cancers, increasingly intensive myeloablative therapies for these cancers, increasingly intensive care for critically ill patients, and increases in the frequency of solid organ and hematopoietic stem cell transplantation. Although diagnostic and therapeutic modalities have improved, mortality rates for invasive mold infections remain high. In this review, we summarize current knowledge about non-Aspergillus mold infections of the chest, with a focus on risk factors, clinical features, diagnosis, and treatment. PMID:20463250

  16. Anisotropic shrinkage characteristics of tape cast alumina

    NASA Astrophysics Data System (ADS)

    Patwardhan, Jaideep Suresh

    Dimensional control during sintering is a major issue in ceramics processing to avoid high post-sintering costs associated with machining of the fired ceramic part to desired tolerances and dimensions. Ceramic forming processes such as tape casting, injection molding, and extrusion involve shear of anisotropic particles resulting in preferential alignment of the particles in the green body. This preferential alignment causes directionality in mechanical, electrical, optical, and magnetic properties and most importantly warpage or distortion during sintering. A large effort has been devoted to synthesizing ceramic green bodies with minimal density gradients and uniform packing and modeling the sintering behavior evolution but little effort has been devoted to characterizing orientation of particles and the effect of preferential alignment on sintering shrinkage anisotropy. A systematic study was initiated to study the effect of processing variables such as shear rate, solids loading, temperature, and binder content on aqueous tape cast alumina. Three different alumina systems: A16-SG, Baikowski RC-UFX DBM and RC-LS DBM were investigated. Aqueous tapes of high solids loading alumina (56 vol. %) were tape cast at various speeds and thicknesses and assuming plane Couette flow a shear rate regime of 21--270 s-1 was investigated. Higher shear rates and high solids loading resulted in higher in-plane anisotropy whereas the anisotropy in the thickness direction was higher for low solids loading systems. The anisotropy was found to be fairly constant above a certain critical shear rate (˜100 s-1) irrespective of the temperature and the solids loading and this correlated with the viscosity-shear rate relationship of the cast slips. The higher shrinkage anisotropy in the thickness direction for the low solids loading systems (35 and 45 vol. %) was attributed to the higher amount of organics in the slip required to sustain the suitable viscosity for tape casting and

  17. Interfacial heat transfer in squeeze casting of magnesium alloy AM60 with variation of applied pressures and casting wall-thicknesses

    NASA Astrophysics Data System (ADS)

    Zhang, Xuezhi; Fang, Li; Sun, Zhizhong; Hu, Henry; Nie, Xueyuan; Tjong, Jimi

    2015-12-01

    The heat transfer coefficient at the casting-die interface is the most important factor on the solidification process. With the 75-ton hydraulic press machine and P20 steel die mold, 5-step castings of magnesium alloy AM60 with different wall-thicknesses (3, 5, 8, 12, 20 mm) were poured under various hydraulic pressures (30, 60, and 90 MPa) using an indirect squeeze casting process. Thermal histories throughout the die wall and the casting surface have been recorded by fine type-K thermocouples. The in-cavity local pressures measured by pressure transducers were explored at the casting-die interfaces of 5 steps. The casting-die interfacial heat transfer coefficients (IHTC) initially reached a maximum peak value followed by a gradually decline to the lower level. Similar characteristics of IHTC peak values can be observed at the applied pressures of 30, 60 and 90 MPa. With the applied pressure of 90 MPa, the peak IHTC values from steps 1 to 5 varied from 5623 to 10,649 W/m2 K. As the applied hydraulic pressure increased, the IHTC peak value of each step was increased accordingly. The wall thickness also affected IHTC peak values significantly. The peak IHTC value and heat flux increased as the step became thicker. The empirical equations relating the IHTCs to the local pressures and the solidification temperature at the casting surface were developed based on the multivariate linear and polynomial regression.

  18. Determination of heat transfer coefficients at metal/chill interface in the casting solidification process

    NASA Astrophysics Data System (ADS)

    Zhang, Liqiang; Li, Luoxing

    2013-08-01

    The present work focuses on the determination of interfacial heat transfer coefficients (IHTCs) between the casting and metal chill during casting solidification. The proposed method is established based on the least-squares technique and sequential function specification method and can be applied to calculate heat fluxes and IHTCs for other alloys. The accuracy and stability of the method has been investigated by using a typical profile of heat fluxes simulating the practical conditions of casting solidification. In the test process, the effects of various calculation parameters in the inverse algorithm are also analyzed. Moreover, numerically calculated and experimental results are compared by applying the determined IHTCs into the forward heat conduction model with the same boundary conditions. The results show that the numerically calculated temperatures are in good agreement with those measured experimentally. This confirms that the proposed method is a feasible and effective tool for determination of the casting-mold IHTCs.

  19. Horizontal and vertical twin-belt casting of 1-inch-thin sections of sheet steel

    SciTech Connect

    Moore, M.R.; Daniel, S.S.; Ozgu, M.R.

    1988-01-01

    Innovative horizontal and vertical twin-belt casting systems were developed and tested in casting trials to provide alternative approaches to solving the crux technical problem of feeding liquid steel into the thin mold gap so as to achieve the excellent as-cast surface quality necessary to allow subsequent direct rolling of top-quality sheet. The horizontal approach involved an innovative feeding system to feed the 1-inch-thick caster entry, but the twin-belt Hazelett machine itself was largely conventional. In contrast, the opened-up entry of the vertical twin-belt machine allowed the use of conventional lathe tube and flux pouring systems, but the machine itself was complex and deformed the casting down to the 1-inch thickness. Extensive modeling work was done to support both approaches. 15 refs., 21 figs., 1 tab.

  20. Preparation of cast aluminum alloy-mica particle composites

    NASA Technical Reports Server (NTRS)

    Deonath, MR.; Bhat, R. T.; Rohatgi, P. K.

    1980-01-01

    A method for making aluminum-mica particle composites is presented in which mica particles are stirred in molten aluminum alloys followed by casting in permanent molds. Magnesium is added either as an alloying element or in the form of pieces to the surface of the alloy melts to disperse up to 3 wt% mica powders in the melts and to obtain high recoveries of mica in the castings. The mechanical properties of the aluminum alloy-mica composite decrease with increasing mica content; however, even at 2.2% it has a tensile strength of 14.22 kg/sq mm with 1.1% elongation, a compression strength of 42.61 kg/sq mm, and an impact strength of 0.30 kgm/sq cm. Cryogenic and self-lubricating bearing are mentioned applications.

  1. Vacuum Die Casting of Silicon Sheet for Photovoltaic Applications

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The development of a vacuum die-casting process for producing silicon sheet suitable for photovoltaic cells with a terrestrial efficiency greater than 12 percent and having the potential to be scaled for large quantity production is considered. The initial approach includes: (1) obtaining mechanical design parameters by using boron nitride, which has been shown to non-wetting to silicon; (2) optimizing silicon nitride material composition and coatings by sessile drop experiments; (3) testing effectiveness of fluoride salt interfacial media with a graphite mold; and (4) testing the effect of surface finish using both boron nitride and graphite. When the material and mechanical boundary conditions are established, a finalized version of the prototype assembly will be constructed and the casting variables determined.

  2. Study of Shell-Mold Thermal Resistance: Laboratory Measurements, Estimation from Compact Strip Production Plant Data, and Observation of Simulated Flux-Mold Interface

    NASA Astrophysics Data System (ADS)

    González de la C., J. Manuel; Flores F., Tania M.; Castillejos E., A. Humberto

    2016-06-01

    The slag film that forms between the shell and mold in steel continuous casting is key in regulating the heat transfer between them. Generally, the mechanisms proposed are related to the phenomena associated with the formation of crystals in the solid layer of the film, such as the appearance of internal pores and surface roughness, which decrease phononic conduction through the layer and interfacial gap with the mold, respectively, and the emergence of crystals themselves, which reduce the transmissivity of infrared radiation across the layer. Due to the importance of the solid layer, this study investigates experimentally the effective thermal resistance, R T, between a hot Inconel surface and a cold Cu surface separated by an initially glassy slag disk, made from powders for casting low and medium-carbon steels, denoted as A and B, respectively. In the tests, an initially mirror-polished disk is sandwiched for 10,800 seconds while the Inconel temperature, away from the disk face, is maintained steady at a value, T c, between 973 K and 1423 K (700 °C and 1150 °C)-below the liquidus temperature of the slags. The disks have a thickness, d t, between ~0.7 and 3.2 mm. Over the range of conditions studied, mold slag B shows R T 33 pct larger than slag A, and microscopic observation of disks hints that the greater resistance arises from the larger porosity developed in B. This finding is supported by high-temperature confocal laser scanning microscope observations of the evolution of the surface of slag parallelepipeds encased between Pt sheets, which reveal that during devitrification the film surface moves outward not inward, contrary with what is widely claimed. This behavior would favor contact of the slag with the mold for both kinds of powders. However, in the case of slag A, the crystalline grains growing at or near the surface pack closely together, leaving only few and small empty spaces. In slag B, crystalline grains pack loosely and many and large empty

  3. Study of Shell-Mold Thermal Resistance: Laboratory Measurements, Estimation from Compact Strip Production Plant Data, and Observation of Simulated Flux-Mold Interface

    NASA Astrophysics Data System (ADS)

    González de la C., J. Manuel; Flores F., Tania M.; Castillejos E., A. Humberto

    2016-08-01

    The slag film that forms between the shell and mold in steel continuous casting is key in regulating the heat transfer between them. Generally, the mechanisms proposed are related to the phenomena associated with the formation of crystals in the solid layer of the film, such as the appearance of internal pores and surface roughness, which decrease phononic conduction through the layer and interfacial gap with the mold, respectively, and the emergence of crystals themselves, which reduce the transmissivity of infrared radiation across the layer. Due to the importance of the solid layer, this study investigates experimentally the effective thermal resistance, R T, between a hot Inconel surface and a cold Cu surface separated by an initially glassy slag disk, made from powders for casting low and medium-carbon steels, denoted as A and B, respectively. In the tests, an initially mirror-polished disk is sandwiched for 10,800 seconds while the Inconel temperature, away from the disk face, is maintained steady at a value, T c, between 973 K and 1423 K (700 °C and 1150 °C)-below the liquidus temperature of the slags. The disks have a thickness, d t, between ~0.7 and 3.2 mm. Over the range of conditions studied, mold slag B shows R T 33 pct larger than slag A, and microscopic observation of disks hints that the greater resistance arises from the larger porosity developed in B. This finding is supported by high-temperature confocal laser scanning microscope observations of the evolution of the surface of slag parallelepipeds encased between Pt sheets, which reveal that during devitrification the film surface moves outward not inward, contrary with what is widely claimed. This behavior would favor contact of the slag with the mold for both kinds of powders. However, in the case of slag A, the crystalline grains growing at or near the surface pack closely together, leaving only few and small empty spaces. In slag B, crystalline grains pack loosely and many and large empty

  4. Sacrificial Plastic Mold With Electroplatable Base

    DOEpatents

    Domeier, Linda A.; Hruby, Jill M.; Morales, Alfredo M.

    2005-08-16

    A sacrificial plastic mold having an electroplatable backing is provided. One embodiment consists of the infusion of a softened or molten thermoplastic through a porous metal substrate (sheet, screen, mesh or foam) and into the features of a micro-scale molding tool contacting the porous metal substrate. Upon demolding, the porous metal substrate will be embedded within the thermoplastic and will project a plastic structure with features determined by the mold tool. This plastic structure, in turn, provides a sacrificial plastic mold mechanically bonded to the porous metal substrate which provides a conducting support suitable for electroplating either contiguous or non-contiguous metal replicates. After electroplating and lapping, the sacrificial plastic can be dissolved to leave the desired metal structure bonded to the porous metal substrate. Optionally, the electroplated structures may be debonded from the porous substrate by selective dissolution of the porous substrate or a coating thereon.

  5. Sacrificial plastic mold with electroplatable base

    DOEpatents

    Domeier, Linda A.; Hruby, Jill M.; Morales, Alfredo M.

    2002-01-01

    A sacrificial plastic mold having an electroplatable backing is provided. One embodiment consists of the infusion of a softened or molten thermoplastic through a porous metal substrate (sheet, screen, mesh or foam) and into the features of a micro-scale molding tool contacting the porous metal substrate. Upon demolding, the porous metal substrate will be embedded within the thermoplastic and will project a plastic structure with features determined by the mold tool. This plastic structure, in turn, provides a sacrificial plastic mold mechanically bonded to the porous metal substrate which provides a conducting support suitable for electroplating either contiguous or non-contiguous metal replicates. After electroplating and lapping, the sacrificial plastic can be dissolved to leave the desired metal structure bonded to the porous metal substrate. Optionally, the electroplated structures may be debonded from the porous substrate by selective dissolution of the porous substrate or a coating thereon.

  6. Custom molded thermal MRg-FUS phantom

    NASA Astrophysics Data System (ADS)

    Eames, Matthew D. C.; Snell, John W.; Hananel, Arik; Kassell, Neal F.

    2012-11-01

    This article describes a method for creating custom-molded thermal phantoms for use with MR-guided focused ultrasound systems. The method is defined here for intracranial applications, though it may be modified for other anatomical targets.

  7. Antimicrobial Treatments of Indoor Mold and Bacteria

    EPA Science Inventory

    Biological contaminants especially mold in buildings are known to act as sources of indoor air pollution, discomfort, asthma and pulmonary disease to building occupants. Sick buildings are evidence of extremely problematic indoor air quality (IAQ), often resulting from unacceptab...

  8. Indoor Molds and Respiratory Hypersensitivity: A Comparison of Selected Molds and House Dust Mite Induced Responses in a Mouse Model**

    EPA Science Inventory

    Molds are ubiquitous in the environment and exposures to molds contribute to various human diseases. Damp/moldy environments have been associated with asthma exacerbation, but mold's role in allergic asthma induction is less clear. The molds selected for these studies are commonl...

  9. Traditional Mold Analysis Compared to a DNA-based Method of Mold Analysis with Applications in Asthmatics' Homes

    EPA Science Inventory

    Traditional environmental mold analysis is based-on microscopic observations and counting of mold structures collected from the air on a sticky surface or culturing of molds on growth media for identification and quantification. A DNA-based method of mold analysis called mol...

  10. Effect of Cooling Rate on Microstructure and Mechanical Properties of Thin-Walled Ductile Iron Castings

    NASA Astrophysics Data System (ADS)

    Górny, Marcin; Tyrała, Edward

    2013-01-01

    This article addresses the effect of cooling rate on microstructure and mechanical properties as determined by changing molding media and section size. The research was conducted for thin-walled iron castings with 2-5-mm wall thickness and for the reference casting with 13-mm wall thickness, using different molding materials (silica sand and insulating sand "LDASC") to achieve various cooling rates. Thermal analysis was performed to determine the real cooling rate at the beginning of the graphite eutectic solidification. In general, it was found that the predictions based on theoretical analysis of the solidification process of ductile iron are in good agreement with the experimental outcomes. Finally, the present study provides insights into the effect of cooling rate on the graphite nodule count, the ferrite fraction and mechanical properties of thin-walled ductile iron castings. The study shows that the cooling rate of thin-walled castings varies in a wide range (80-15 °C/s) when changing the wall thickness from 2 to 5 mm, accompanied by significantly changing the mechanical properties of ductile iron. The cooling rate can be effectively reduced by applying an insulating sand to obtain the desired properties of thin-walled castings practically in the whole range of ductile iron grades in accordance with the ASTM Standard.

  11. Freeform fabrication of tissue-simulating phantoms by combining three-dimensional printing and casting

    NASA Astrophysics Data System (ADS)

    Shen, Shuwei; Zhao, Zuhua; Wang, Haili; Han, Yilin; Dong, Erbao; Liu, Bin; Liu, Wendong; Cromeens, Barrett; Adler, Brent; Besner, Gail; Ray, William; Hoehne, Brad; Xu, Ronald

    2016-03-01

    Appropriate surgical planning is important for improved clinical outcome and minimal complications in many surgical operations, such as a conjoined twin separation surgery. We combine 3D printing with casting and assembling to produce a solid phantom of high fidelity to help surgeons for better preparation of the conjoined twin separation surgery. 3D computer models of individual organs were reconstructed based on CT scanned data of the conjoined twins. The models were sliced, processed, and converted to an appropriate format for Fused Deposition Modeling (FDM). The skeletons of the phantom were printed directly by FDM using Acrylonitrile-Butadiene-Styrene (ABS) material, while internal soft organs were fabricated by casting silicon materials of different compositions in FDM printed molds. The skeleton and the internal organs were then assembled with appropriate fixtures to maintain their relative positional accuracies. The assembly was placed in a FMD printed shell mold of the patient body for further casting. For clear differentiation of different internal organs, CT contrast agents of different compositions were added in the silicon cast materials. The produced phantom was scanned by CT again and compared with that of the original computer models of the conjoined twins in order to verify the structural and positional fidelity. Our preliminary experiments showed that combining 3D printing with casting is an effective way to produce solid phantoms of high fidelity for the improved surgical planning in many clinical applications.

  12. Determination of the metal/die interfacial heat transfer coefficient of high pressure die cast B390 alloy

    NASA Astrophysics Data System (ADS)

    Cao, Yongyou; Guo, Zhipeng; Xiong, Shoumei

    2012-07-01

    High-pressure die cast B390 alloy was prepared on a 350 ton cold chamber die casting machine. The metal/die interfacial heat transfer coefficient of the alloy was investigated. Considering the filling process, a "finger"-shaped casting was designed for the experiments. This casting consisted of five plates with different thicknesses (0.05 inch or 1.27 mm to 0.25 inch or 6.35 mm) as well as individual ingates and overflows. Experiments under various operation conditions were conducted, and temperatures were measured at various specific locations inside the die. Based on the results, the interfacial heat transfer coefficient and heat flux were determined by solving the inverse heat transfer problem. The influence of the mold-filling sequence, sensor locations, as well as processing parameters including the casting pressure, die temperature, and fast/slow shot speeds on the heat transfer coefficient were discussed.

  13. A computational study of low-head direct chill slab casting of aluminum alloy AA2024

    NASA Astrophysics Data System (ADS)

    Hasan, Mainul; Begum, Latifa

    2016-04-01

    The steady state casting of an industrial-sized AA2024 slab has been modeled for a vertical low-head direct chill caster. The previously verified 3-D CFD code is used to investigate the solidification phenomena of the said long-range alloy by varying the pouring temperature, casting speed and the metal-mold contact heat transfer coefficient from 654 to 702 °C, 60-180 mm/min, and 1.0-4.0 kW/(m2 K), respectively. The important predicted results are presented and thoroughly discussed.

  14. Mold contamination and air handling units.

    PubMed

    Wilson, Stephen C; Palmatier, Robert N; Andriychuk, Larysa A; Martin, Jared M; Jumper, Cynthia A; Holder, Homer W; Straus, David C

    2007-07-01

    An investigation was conducted on selected locations in air handling units (AHUs) to (a) identify common mold species found on these locations, (b) determine whether some locations (and subsets) featured mold growth sites more frequently than others, (c) ascertain whether the operating condition of AHUs is related to mold contamination, and (d) provide a basis for a microbial sampling protocol for AHUs. A total of 566 tape lifts and 570 swab samples were collected from the blower wheel fan blades, insulation, cooling coil fins, and ductwork from 25 AHUs. All AHU conditions were numerically rated using a heating, ventilation and air-conditioning (HVAC) survey. Results showed that Cladosporium sp. fungi were commonly recovered in terms of growth sites and deposited spores, and they were found mainly in the blower wheel fan blades, the ductwork, and the cooling coil fins. Subsections of the fan blades, insulation, and cooling coil fins showed no preferred area for mold growth sites. Other organisms such as Penicillium sp., Aspergillus sp., and Paecilomyces sp. were recovered from the cooling coil fins and insulation. Because of the widespread prevalence of Cladosporium sp., there was no relationship between mold growth and operating condition. However, the presence of different species of molds in locations other than the blower wheel blades may indicate that the AHU condition is not optimal. A suggested microbial sampling protocol including interpretations of sample results is presented. PMID:17487721

  15. Integrated mold/surface-micromachining process

    SciTech Connect

    Barron, C.C.; Fleming, J.G.; Montague, S.; Sniegowski, J.J.; Hetherington, D.L.

    1996-03-01

    We detail a new monolithically integrated silicon mold/surface-micromachining process which makes possible the fabrication of stiff, high-aspect-ratio micromachined structures integrated with finely detailed, compliant structures. An important example, which we use here as our process demonstration vehicle, is that of an accelerometer with a large proof mass and compliant suspension. The proof mass is formed by etching a mold into the silicon substrate, lining the mold with oxide, filling it with mechanical polysilicon, and then planarizing back to the level of the substrate. The resulting molded structure is recessed into the substrate, forming a planar surface ideal for subsequent processing. We then add surface-micromachined springs and sense contacts. The principal advantage of this new monolithically integrated mold/surface-micromachining process is that it decouples the design of the different sections of the device: In the case of a sensitive accelerometer, it allows us to optimize independently the proof mass, which needs to be as large, stiff, and heavy as possible, and the suspension, which needs to be as delicate and compliant as possible. The fact that the high-aspect-ratio section of the device is embedded in the substrate enables the monolithic integration of high-aspect-ratio parts with surface-micromachined mechanical parts, and, in the future, also electronics. We anticipate that such an integrated mold/surface micromachining/electronics process will offer versatile high-aspect-ratio micromachined structures that can be batch-fabricated and monolithically integrated into complex microelectromechanical systems.

  16. The formation of oscillation marks in the continuous casting of steel slabs

    NASA Astrophysics Data System (ADS)

    Takeuchi, E.; Brimacombe, J. K.

    1984-09-01

    The formation of oscillation marks on the surface of continuously cast slabs has been studied by metallographically examining slab samples and by performing a set of mathematical analyses of heat flow, lubrication, and meniscus shape in the meniscus region of the mold. The metallographic study has revealed that, in agreement with previous work, the oscillation marks can be classified principally according to the presence or absence of a small “hook” in the subsurface structure at the base of individual oscillation marks. The depth of the oscillation marks exhibiting subsurface hooks varies with the carbon content, reaching a maximum at about 0.1 pct carbon, while the oscillation marks without hooks show no carbon dependence. The analysis of heat flow at the meniscus, which is based on a measured mold heat-flux distribution, indicates that depending on the level of superheat, the meniscus may partially freeze within the period of a typical mold oscillation cycle. Lubrication theory has shown that, owing to the geometry of the mold flux channel between the solidifying shell at the meniscus and the straight mold wall, significant pressure gradients capable of deforming the meniscus can be generated in the flux by the reciprocating motion of the mold relative to the shell. A force balance on the interface between the steel and the mold flux has been applied to compute the shape of the meniscus as a function of the pressure developed in the lubricating flux at different stages in the mold oscillation cycle. This has demonstrated that the “contact” point between the meniscus and mold moves out of phase with (by π/2), and has a greater amplitude than, the mold displacement so that just at, or near, the end of the negative strip time molten steel can overflow at the meniscus. From these studies a reasonable mechanism of oscillation-mark formation emerges which involves interaction between the oscillating mold and the meniscus via pressure gradients in the mold

  17. Cast aluminum alloys containing dispersions of zircon particles

    NASA Astrophysics Data System (ADS)

    Banerji, A.; Surappa, M. K.; Rohatgi, P. K.

    1983-06-01

    A process for preparing Al-alloy castings containing dispersions of zircon particles is described. Composites were prepared by stirring zircon particles (40 to 200 µm size) in commercially pure Al (99.5 pct)* and Al-11.8 pct Si melts and subsequently casting these melts in permanent molds. It was found to be necessary to alloy the above two melts with 3 pct Mg to disperse substantial amounts of zircon particles (25 to 30 pct). Further, it was possible to disperse up to 60 wt pct zircon by adding up to 5 pct Mg; however, the melts containing above 30 wt pct zircon showed insufficient fluidity for gravity diecasting and had to be pressure diecast. Microstructural studies of cast composites indicated the presence of a reaction zone at the periphery of zircon particles, and electron probe microanalysis showed concentrations of Mg and Si at the particle-matrix interface. Hardness, abrasive wear resistance, elastic modulus, 0.2 pct proof stress, and tensile strength of cast Al-3 pct Mg alloy were found to improve with the dispersions of zircon particles. Scanning electron micrographs of abraded and fractured surfaces did not show any evidence of particle pull-outs or voids at the particle matrix interface, indicating strong continuous bonding.

  18. CAST FLOOR WITH VIEW OF TORPEDO LADLE (BENEATH CAST FLOOR) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CAST FLOOR WITH VIEW OF TORPEDO LADLE (BENEATH CAST FLOOR) AND KEEPERS OF THE CAST HOUSE FLOOR, S.L. KIMBROUGH AND DAVID HOLMES. - U.S. Steel, Fairfield Works, Blast Furnace No. 8, North of Valley Road, West of Ensley-Pleasant Grove Road, Fairfield, Jefferson County, AL

  19. Elimination or Minimization of Oscillation Marks: A Path To Improved Cast Surface Quality

    SciTech Connect

    Dr. Alan W. Cramb

    2007-12-17

    Oscillation marks are the most recognizable feature of continuous casting and can be related to the subsurface defects that can be found on product rolled from continuous cast slabs. The purpose of this work was to develop strategies that can be used on industrial continuous casters to reduce oscillation mark depth and, in particular, to minimize the formation of hook type defects that are prevalent on ultra low carbon grades. The major focus of the work was on developing a technique to allow heat transfer in the meniscus region of the continuous caster to be measured and the effect of mold slag chemistry and chrystallization to be documented. A new experimental technique was developed that allowed the effect of mold flux chemistry and chrystallization on the radiation heat transfer rate to be measured dynamically.

  20. Ultra Large Castings to Produce Low Cost Aluminum Vehicle Structures

    SciTech Connect

    T. N. Meyer; M. J. Kinosz; E. M. Bradac; M. Mbaye; J. T. Burg; M. A. Klingensmith

    1999-04-26

    Through a cooperative effort with the U.S. Department of Energy (DOE) Office of Heavy Vehicle Technologies (OHVT), Alcoa is developing a casting process to produce ultra large thin wall components. The casting process is a low pressure, metal mold, multiport injection vertical casting process. The specific system for demonstration of the process is located at Alcoa's Technology Center and will be capable of producing parts extending 3 M long, 1.7 M wide and 0.4 M high. For example, single castings of car floor pan frames or side wall aperture structures are candidates for this installation. This shall provide a major opportunity to reduce the cost of lightweight transportation vehicle structures by (a) reducing the components or part count and (b) reducing the cost of assembly. To develop and demonstrate the process, an inner panel of the Chrysler minivan liftgate will be first produced on this system. Through computer analyses, the cast inner panel design was developed to satisfy both structural performance and casting process requirements. Currently, this is an 11 part assembly of steel components. At the time of this abstract, the numerous system components are in various phases of fabrication and site preparation is fully underway, with system shakedown beginning in the second quarter of 1999. Successful demonstration of caster system operation is anticipated to occur during the third quarter and production of a high quality product during the fourth quarter. Although the process is targeted toward reducing the cost of lightweight trucks, buses and autos, consideration is being given to application in the aircraft industry.