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1

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

SciTech Connect

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.

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

2003-05-01

2

Wear Properties of Thixoformed and High Pressure Die Cast Aluminium Alloys for Connecting Rod Applications in Compressors  

Microsoft Academic Search

Hypereutectic aluminium casting alloys are attractive candidates for connecting rod applications in compressors. The wear properties of these alloys are largely controlled by their microstructural features which in turn are affected by the processing route. Several hypo- and hypereutectic Al-Si alloys were produced by high pressure die casting and thixoforming in the present work. The former route produced a very

Yuecel Birol; Feriha Birol

2007-01-01

3

Sputtered protective coatings for die casting dies  

NASA Technical Reports Server (NTRS)

This investigation determined whether selected ion beam sputtered coatings on H-13 die steel would have the potential of improving the thermal fatigue behavior of the steel used as a die in aluminum die casting. The coatings were selected to test candidate insulators and metals capable of providing protection of the die surface. The studies indicate that 1 micrometer thick W and Pt coatings reduced the thermal fatigue more than any other coating tested and are candidates to be used on a die surface to increase die life.

Mirtich, M. J.; Nieh, C. Y.; Wallace, J. F.

1981-01-01

4

Casting Characteristics of Aluminum Die Casting Alloys  

SciTech Connect

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.

Makhlouf M. Makhlouf; Diran Apelian

2002-02-05

5

Wear properties of high-pressure die cast and thixoformed aluminium alloys for connecting rod applications in compressors  

Microsoft Academic Search

Hypereutectic Al–Si casting alloys are attractive candidates for connecting rod applications in compressors. Several hypo- and hypereutectic Al–Si alloys were produced by high-pressure die casting and thixoforming in the present work. Hypereutectic Al–Si alloys wear less than the near-eutectic and hypoeutectic alloys under the severe wear conditions encountered in compressors, confirming the impact of Si on wear resistance. Cu also

Yücel Birol; Feriha Birol

2008-01-01

6

Measurement of Heat Flux and Heat Transfer Coefficient Due to Spray Application for the Die Casting Process  

SciTech Connect

Lubricant spray application experiments were conducted for the die casting process. The heat flux was measured in situ using a differential thermopile sensor for three application techniques. First, the lubricant was applied under a constant flowrate while the nozzle was held in the same position. Second, the lubricant was applied in a pulsed, static manner, in which the nozzle was held over the same surface while it was turned on and off several times. Third, the lubricant was applied in a sweeping manner, in which the nozzle was moved along the die surface while it was held open. The experiments were conducted at several die temperatures and at sweep speeds of 20, 23, and 68 cm/s. The heat flux data, which were obtained with a sensor that was located in the centre of the test plate, were presented and discussed. The sensor can be used to evaluate lubricants, monitor the consistency of die lubrication process, and obtain useful process data, such as surface temperature, heat flux, and heat transfer coefficients. The heat removed from the die surface during lubricant application is necessary for (a) designing the cooling channels in the die, i.e. their size and placement, and (b) performing accurate numerical simulations of the die casting process.

Sabau, Adrian S [ORNL

2007-01-01

7

Wear Properties of Thixoformed and High Pressure Die Cast Aluminium Alloys for Connecting Rod Applications in Compressors  

NASA Astrophysics Data System (ADS)

Hypereutectic aluminium casting alloys are attractive candidates for connecting rod applications in compressors. The wear properties of these alloys are largely controlled by their microstructural features which in turn are affected by the processing route. Several hypo- and hypereutectic Al-Si alloys were produced by high pressure die casting and thixoforming in the present work. The former route produced a very fine microstructure while relatively coarser, globular ?-Al matrix dominated in thixoformed grades. A modified Falex Block on Ring equipment was employed to investigate the wear properties of these alloys. Wear tests were carried out under service conditions in the lubricated state at 75°C. The superior wear properties of hypereutectic alloys produced by high pressure die casting with respect to the thixoformed variety is accounted for by the very fine microstructure with a fine dispersion of primary Si particles in the former. Of the two production routes employed, thixoforming had a favorable effect on wear properties at equal Si levels.

Birol, Yücel; Birol, Feriha

2007-04-01

8

Energy Consumption of Die Casting Operations  

SciTech Connect

Molten metal processing is inherently energy intensive and roughly 25% of the cost of die-cast products can be traced to some form of energy consumption [1]. The obvious major energy requirements are for melting and holding molten alloy in preparation for casting. The proper selection and maintenance of melting and holding equipment are clearly important factors in minimizing energy consumption in die-casting operations [2]. In addition to energy consumption, furnace selection also influences metal loss due to oxidation, metal quality, and maintenance requirements. Other important factors influencing energy consumption in a die-casting facility include geographic location, alloy(s) cast, starting form of alloy (solid or liquid), overall process flow, casting yield, scrap rate, cycle times, number of shifts per day, days of operation per month, type and size of die-casting form of alloy (solid or liquid), overall process flow, casting yield, scrap rate, cycle times, number of shifts per day, days of operation per month, type and size of die-casting machine, related equipment (robots, trim presses), and downstream processing (machining, plating, assembly, etc.). Each of these factors also may influence the casting quality and productivity of a die-casting enterprise. In a die-casting enterprise, decisions regarding these issues are made frequently and are based on a large number of factors. Therefore, it is not surprising that energy consumption can vary significantly from one die-casting enterprise to the next, and within a single enterprise as function of time.

Jerald Brevick; clark Mount-Campbell; Carroll Mobley

2004-03-15

9

Prediction of Part Distortion in Die Casting  

SciTech Connect

The die casting process is one of the net shape manufacturing techniques and is widely used to produce high production castings with tight tolerances for many industries. An understanding of the stress distribution and the deformation pattern of parts produced by die casting will result in less deviation from the part design specification, a better die design and eventually more productivity and cost savings. This report presents methods that can be used to simulate the die casting process in order to predict the deformation and stresses in the produced part and assesses the degree to which distortion modeling is practical for die casting at the current time. A coupled thermal-mechanical finite elements model was used to simulate the die casting process. The simulation models the effect of thermal and mechanical interaction between the casting and the die. It also includes the temperature dependant material properties of the casting. Based on a designed experiment, a sensitivity analysis was conducted on the model to investigate the effect of key factors. These factors include the casting material model, material properties and thermal interaction between casting and dies. To verify the casting distortion predictions, it was compared against the measured dimensions of produced parts. The comparison included dimensions along and across the parting plane and the flatness of one surface.

R. Allen Miller

2005-03-30

10

Application of TPM indicators for analyzing work time of machines used in the pressure die casting  

NASA Astrophysics Data System (ADS)

The article presents the application of total productive maintenance (TPM) to analyze the working time indicators of casting machines with particular emphasis on failures and unplanned downtime to reduce the proportion of emergency operation for preventive maintenance and diagnostics. The article presents that the influence of individual factors of complex machinery maintenance (TPM) is different and depends on the machines' modernity level. In an original way, by using correlation graphs, research findings on the impact of individual TPM factors on the castings quality were presented and interpreted. The examination results conducted for machines with varying modernity degrees allowed to determine changes within the impact of individual TPM factors depending on machine parameters. These results provide a rich source of information for the improvement processes on casting quality of the foundry industry that satisfies the automotive industry demand.

Borkowski, Stanis?aw; Czajkowska, Agnieszka; Stasiak-Betlejewska, Renata; Borade, Atul B.

2014-05-01

11

Reliability evaluation of a laser repaired die-casting die  

Microsoft Academic Search

The fatigue life of the die-casting dies depends on the heat checks, which are characterized by fine shallow cracks on the surface due to cyclic thermal stress. According to the recent study, laser-processing is effective to repair cracks and extend the life of dies. The purpose of this study is to develop a reliability evaluation method for laser repaired die

Richun Song; Satoshi Hanaki; Masato Yamashita; Hitoshi Uchida

2008-01-01

12

Use of RSP Tooling to Manufacture Die Casting Dies  

SciTech Connect

The technology and art used to construct die casting dies has seen many improvements over the years. However, the time lag from when a design is finalized to the time a tool is in production has remained essentially the same. The two main causes for the bottleneck are the need to qualify a part design by making prototypes (usually from an alternative process), and the production tooling lead time after the prototypes are approved. Production tooling costs are high due to the labor and equipment costs associated with transforming a forged block of tool steel into a finished tool. CNC machining, sink EDM, benching, engraving and heat treatment unit operations are typically involved. As a result, there is increasing interest in rapid tooling (RT) technologies that shorten the design-to-part cycle and reduce the cost of dies. There are currently more than 20 RT methods being developed and refined around the world (1). The "rapid" in rapid tooling suggests time compression for tool delivery, but does not address robustness as nearly all RT approaches are intended for low-volume prototype work, primarily for molding plastics. Few options exist for die casting. An RT technology suitable for production-quality tooling in the time it normally takes for prototype tooling is highly desirable. In fact, there would be no need for a distinction between prototype and production tooling. True prototype parts could be made using the same processing conditions and materials intended for production. Qualification of the prototype part would allow the manufacturer to go directly into production with the same tool. A relatively new RT technology, Rapid Solidification Process (RSP) Tooling, is capable of making production-quality tooling in an RT timeframe for die casting applications. RSP Tooling, was developed at the Idaho National Engineering and Environmental Laboratory (INEEL), and commercialized with the formation of RSP Tooling, LLC (2). This paper describes the process, and summarizes properties of H13 tool steel dies.

Kevin McHugh

2004-07-01

13

Enhancements in Magnesium Die Casting Impact Properties  

SciTech Connect

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% in AM50 to over 9% in AZ91, more of the intermetallic Mg17Al12 is formed in the microstructure. For instance, for 15 increase in the aluminum content from AM50 to AM60, the volume fraction of eutectic present in the microstructure increases by 35%! Eventually, the brittle Mg17Al12 compound forms an interconnected network that reduces ductility and impact resistance. The lower aluminum in AM50 and AM60 are therefore a desirable feature in applications that call for higher impact resistance. Further improvement in impact resistance depends on the processing condition of the casting. Sound castings without porosity and impurities will have better mechanical properties. Since magnesium oxidizes readily, good melting and metal transfer practices are essential. The liquid metal has to be protected from oxidation at all times and entrainment of oxide films in the casting needs to be prevented. In this regard, there is evidence that us of vacuum to evacuate air from the die casting cavity can improve the quality of the castings. Fast cooling rates, leading to smaller grain size are beneficial and promote superior mechanical properties. Micro-segregation and banding are two additional defect types often encountered in magnesium alloys, in particular in AZ91D. While difficult to eliminate, segregation can be minimized by careful thermal management of the dies and the shot sleeve. A major source of segregation is the premature solidification in the shot sleeve. The primary solid dendrites are carried into the casting and form a heterogeneous structure. Furthermore, during the shot, segregation banding can occur. The remedies for this kind of defects include a hotter shot sleeve, use of insulating coatings on the shot sleeve and a short lag time between pouring into the shot sleeve and the shot.

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

2000-06-30

14

A study of erosion in die casting dies by a multiple pin accelerated erosion test  

Microsoft Academic Search

An accelerated erosion test was developed to evaluate the erosion resistance of die materials and coatings for die casting\\u000a application. An acceleration in wear was achieved by selecting pyramid-shaped core pins, hypereutectic aluminum silicon casting\\u000a alloy, high melt temperatures and high gate velocities. Multiple pin design was selected to enable multiple test sites for\\u000a comparative evaluation. Apilot run was conducted

R. Shivpuri; M. Yu; K. Venkatesan; Y.-L Chu

1995-01-01

15

Spray-formed tooling for injection molding and die casting applications  

SciTech Connect

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.

K. M. McHugh; B. R. Wickham

2000-06-26

16

Spray-formed Tooling for Injection Molding and Die Casting Applications  

SciTech Connect

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.

Mc Hugh, Kevin Matthew

2000-06-01

17

National Metal Casting Research Institute final report. Volume 2, Die casting research  

SciTech Connect

Four subprojects were completed: development and evaluation of die coatings, accelerated die life characterization of die materials, evaluation of fluid flow and solidification modeling programs, selection and characterization of Al-based die casting alloys, and influence of die materials and coatings on die casting quality.

Jensen, D. [University of Northern Iowa, Cedar Falls, IA (United States). Dept. of Industrial Technology] [comp.

1994-06-01

18

A study of erosion in die casting dies by a multiple pin accelerated erosion test  

NASA Astrophysics Data System (ADS)

An accelerated erosion test was developed to evaluate the erosion resistance of die materials and coatings for die casting application. An acceleration in wear was achieved by selecting pyramid-shaped core pins, hypereutectic aluminum silicon casting alloy, high melt temperatures and high gate velocities. Multiple pin design was selected to enable multiple test sites for comparative evaluation. Apilot run was conducted on a 300 ton commercial die casting machine at various sites (pins) to verify the thermal and flow similarities. Subsequently, campaigns were run on two different 300 ton commercial die casting machines to evaluate H13 die material and different coatings for erosive resistance. Coatings and surface treatments evaluated included surface micropeening, titanium nitride, boron carbide, vanadium carbide, and metallic coatings—tungsten, molybdenum, and platinum. Recent campaigns with different melt temperatures have indicated a possible link between soldering phenomena and erosive wear. This paper presents the details of the test set up and the results of the pilot and evaluation tests.

Shivpuri, R.; Yu, M.; Venkatesan, K.; Chu, Y.-L.

1995-04-01

19

Die Casting Part Distortion: Prediction and Attenuation  

SciTech Connect

The goal of this research was to predict the part deformation and residual stresses after ejection from the die and cooling to room temperature. A finite element model was built to achieve this goal and several modeling techniques were investigated throughout this research. Die-casting is a very complex process and the researchers are faced with a large number of hard to solve physical problems when modeling the process. Several assumptions are made in our simulation model. The first significant assumption is the instantaneous cavity filling. This means that the cavity filling stage is not considered in our model. Considering the cavity filling stage increases the modeling complexity as a result of different flow patterns. expected in the shot sleeve, gate, runner and different cavity features. The flow of gas from the cavity through the vents is another problem that is ignored in our model as a result of this assumption. Our second assumption is that the cast metal has uniform temperature distribution inside the cavity, at the starting point of simulation. This temperature is assumed to be over liquidus limit, i.e. the solid fraction is 0.0% of the cast metal. The third assumption is due to ABAQUS (commercial software used in this research) limitations. ABAQUS cannot deal with multi-phase models; therefore we use solid elements to define the casting instead of multi-phase (liquid/solid) elements. Liquid elements can carry the hydrostatic pressure from the shot sleeve and apply it on the cavity surfaces, while the solid elements do not have this capability. To compensate for this assumption we add the cavity pressure as a boundary condition and apply it on the cavity surface separately from the part. Another issue with this assumption is that, liquid casting can follow the cavity shape when it distorts. With the use of solid elements to represent the casting during its liquid state, it loses this capability to follow the cavity. Several techniques were tested to overcome this problem.

Dr, R. Allen Miller

2002-02-12

20

Deburring die-castings by wet vibratory plant  

NASA Technical Reports Server (NTRS)

A wet vibratory procedure for the removal of burrs from die castings is described. In this process synthetic abrasive chips and detergent solutions are agitated with the work in such a way as to produce a spiral circulatory movement. Details of various forms of vibrator basin and shapes of abrasive are illustrated. The automation of deburring is illustrated through the application of vibrators of spiral design in combination with transport and drying devices.

Loeschbart, H. M.

1980-01-01

21

Development of Thin Section Zinc Die Casting Technology  

SciTech Connect

A new high fluidity zinc high pressure die casting alloy, termed the HF alloy, was developed during laboratory trials and proven in industrial production. The HF alloy permits castings to be achieved with section thicknesses of 0.3 mm or less. Technology transfer activities were conducted to develop usage of the HF high fluidity alloy. These included production of a brochure and a one-hour webinar on the HF alloy. The brochure was then sent to 1,184 product designers in the Interzinc database. There was excellent reception to this mailing, and from this initial contact 5 technology transfer seminars were conducted for 81 participants from 30 companies across a wide range of business sectors. Many of the successful applications to date involve high quality surface finishes. Design and manufacturing assistance was given for development of selected applications.

Goodwin, Frank [International Lead Zinc Research Org., Inc.] [International Lead Zinc Research Org., Inc.

2013-10-31

22

Microstructures and properties of aluminum die casting alloys  

SciTech Connect

This document provides descriptions of the microstructure of different aluminum die casting alloys and to relate the various microstructures to the alloy chemistry. It relates the microstructures of the alloys to their main engineering properties such as ultimate tensile strength, yield strength, elongation, fatigue life, impact resistance, wear resistance, hardness, thermal conductivity and electrical conductivity. Finally, it serves as a reference source for aluminum die casting alloys.

M. M. Makhlouf; D. Apelian; L. Wang

1998-10-01

23

Hard coatings produced by PACVD applied to aluminium die casting  

Microsoft Academic Search

The advantages of using different types of hard coatings in the field of aluminium die casting have been demonstrated in several publications. Hard coatings can protect the steel surface of casting tools from erosion of liquid aluminium and improve the resistance against thermal cracking. The coatings are also expected to prevent the aluminium from soldering onto the tool surface. Lifetime

D. Heim; F. Holler; C. Mitterer

1999-01-01

24

The thermal fatigue resistance of H-13 Die Steel for aluminum die casting dies  

NASA Technical Reports Server (NTRS)

The effects of welding, five selected surface coatings, and stress relieving on the thermal fatigue resistance of H-13 Die Steel for aluminum die casting dies were studied using eleven thermal fatigue specimens. Stress relieving was conducted after each 5,000 cycle interval at 1050 F for three hours. Four thermal fatigue specimens were welded with H-13 or maraging steel welding rods at ambient and elevated temperatures and subsequently, subjected to different post-weld heat treatments. Crack patterns were examined at 5,000, 10,000, and 15,000 cycles. The thermal fatigue resistance is expressed by two crack parameters which are the average maximum crack and the average cracked area. The results indicate that a significant improvement in thermal fatigue resistance over the control was obtained from the stress-relieving treatment. Small improvements were obtained from the H-13 welded specimens and from a salt bath nitrogen and carbon-surface treatment. The other surface treatments and welded specimens either did not affect or had a detrimental influence on the thermal fatigue properties of the H-13 die steel.

1982-01-01

25

Improving the Efficiency of Die Casting Machine Hydraulic Systems with the Retrofit of Adjustable Frequency Drives  

E-print Network

Die casting is a common method of light metal processing which is used to produce accurately dimensioned, sharply defined metal parts. Most die casting machines in use today utilize a complex hydraulic system to perform the necessary work required...

Ambs, L.; Kosanovic, D.; Edberg, C.

26

Manufacture of die casting dies by hot isostatic pressing. CRADA final report  

SciTech Connect

The reason for this Cooperative Research and Development Agreement (CRADA) between the Oak Ridge National Laboratory (ORNL) and Doehler-Jarvis was to investigate the manufacture die-casting dies with internal water-cooling lines by hot-isostatic pressing (HIPing) of H13 tool steel powder. The use of HIPing will allow the near-net-shape manufacture of dies and the strategic placement of water-cooling lines during manufacture. The production of near-net-shape dies by HIPing involves the generation of HIPing diagrams, the design of the can that can be used for HIPing a die with complex details, strategic placement of water-cooling lines in the die, computer modeling to predict movement of the water lines during HIPing, and the development of strategies for placing water lines in the appropriate locations. The results presented include a literature review, particle analysis and characterization of H13 tool steel powder, and modeling of the HIPing process.

Viswanathan, S.; Ren, W.; Luk, K. [Oak Ridge National Lab., TN (United States); Brucher, H.G. [Doehler-Jarvis, Toledo, OH (United States)

1998-09-01

27

Assessment of Computer Simulation Software and Process Data for High Pressure Die Casting of Magnesium  

SciTech Connect

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.

Sabau, Adrian S [ORNL; Hatfield, Edward C [ORNL; Dinwiddie, Ralph Barton [ORNL; Kuwana, Kazunori [University of Kentucky; Viti, Valerio [University of Kentucky, Lexington; Hassan, Mohamed I [University of Kentucky, Lexington; Saito, Kozo [University of Kentucky

2007-09-01

28

Determination of the metal/die interfacial heat transfer coefficient of high pressure die cast B390 alloy  

NASA Astrophysics Data System (ADS)

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.

Cao, Yongyou; Guo, Zhipeng; Xiong, Shoumei

2012-07-01

29

High-Pressure Die-Casting: Contradictions and Challenges  

NASA Astrophysics Data System (ADS)

High-pressure die casting (HPDC) is particularly suitable for high production rates and it is applied in several industrial fields; actually, approximately half of the world production of light metal castings is obtained by this technology. An overview of the actual status of HPDC technology is described in the current work, where both critical aspects and potential advantages are evidenced. Specific attention is paid to the quality requirements from the end users, as well as to the achievable production rate, the process monitoring and control, and the European and worldwide scenario. This overview leads to individuate the most relevant challenges for HPDC industry: "zero-defect" production, real-time process control, understanding the role of the process variables, process optimization, introduction of research and development activities, and disseminating the knowledge about HPDC technology. Performing these actions, HPDC foundries could achieve a more mature and efficient approach to large end users and exploit their really relevant potential.

Bonollo, Franco; Gramegna, Nicola; Timelli, Giulio

2015-02-01

30

Investment cast AISI H13 tooling for automotive applications  

SciTech Connect

While many techniques exist for production of soft tooling, for die casting there is limited recent experience with cast tooling. The most common US alloy used for manufacture of die casting tooling is wrought AISI H13. If the performance of the cast material is comparable to the wrought counterpart, the use of investment cast HI 3 tooling directly from patterns made via rapid prototyping is of considerable interest. A metallurgical study of investment cast H13 was conducted to evaluate the mechanical behavior in simulated die casting applications. Variable thickness plate investment castings of AISI H13 hot work die steel were produced and characterized in the as-cast and heat-treated conditions. The characterization included light microscopy and mechanical testing. Wrought samples of standard and premium grade H13 were heat-treated and characterized similarly for comparison. Microstructural differences were observed in as-cast samples produced in different section thicknesses. Dendrite cell size and carbide morphology constituted the most prominent microstructural differences observed. After a full heat-treatment, microstructural differences between the wrought material and cast materials were slight regardless of section thickness.The mechanical properties of the cast and heat-treated material proved similar to the properties of the standard heat-treated wrought material. A thermal fatigue testing unit was to con-elate the heat checking susceptibility of H13 steel to its processing and consequent microstructural condition. Surface hardness decreased significantly with thermal cycling, and heat checking was observed in as few as 50 cycles. Thermal softening and thermal fatigue susceptibility were quantified and discussed relative to the microstructural conditions created by processing and heat-treatment. It was found that the premium grade wrought H13 steel provided the best overall resistance to heat checking.

Maguire, M.C.; Baldwin, M.D. [Sandia National Labs., Albuquerque, NM (United States); Hochanadel, P.W.; Edwards, G.R. [Colorado School of Mines, Golden, OH (United States)

1995-07-01

31

Longitudinal study of workers of an aluminium die casting factory.  

PubMed

We conducted a 5-year longitudinal study on 76 workers of a high and medium aluminium alloy die-casting factory. As in a previous cross-sectional study conducted in 1986 and in accordance with the data in the literature, the 1990 follow-up study showed: a low prevalence of chronic bronchitis (as defined by the ECSC questionnaire on respiratory symptoms); normal mean functional values of FVC, FEV1, FEV1/FVC%. We did not find any significant difference in the levels of lung function over the period of 1986-90. These results show that workers in the secondary aluminium industry are not exposed to a significant risk of chronic pulmonary disease. PMID:1297059

Discalzi, G L; Capellaro, F; Baracco, A

1992-01-01

32

Die Materials for Critical Applications and Increased Production Rates  

SciTech Connect

Die materials for aluminum die-casting need to be resistant to heat checking, and have good resistance to washout and to soldering in a fast flow of molten aluminum. To resist heat checking, die materials should have a low coefficient of thermal expansion, high thermal conductivity, high hot yield strength, good temper softening resistance, high creep strength, and adequate ductility. To resist the washout and soldering, die materials should have high hot hardness, good temper resistance, low solubility in molten aluminum and good oxidation resistance. It is difficult for one material to satisfy with all above requirements. In practice, H13 steel is the most popular material for aluminum die casting dies. While it is not an ideal choice, it is substantially less expensive to use than alternative materials. However, in very demanding applications, it is sometimes necessary to use alternative materials to ensure a reasonable die life. Copper-base, nickel-base alloys and superalloys, titanium-,molybdenum-, tungsten-base alloys, and to some extent yttrium and niobium alloys, have all been considered as potential materials for demanding die casting applications. Most of these alloys exhibit superior thermal fatigue resistance, but suffer from other shortcomings.

David Schwam; John Wallace; Sebastian Birceanu

2002-11-30

33

Modeling and Analysis of The Pressure Die Casting Using Response Surface Methodology  

SciTech Connect

Pressure die casting is successfully used in the manufacture of Aluminum alloys components for automobile and many other industries. Die casting is a process involving many process parameters having complex relationship with the quality of the cast product. Though various process parameters have influence on the quality of die cast component, major influence is seen by the die casting machine parameters and their proper settings. In the present work, non-linear regression models have been developed for making predictions and analyzing the effect of die casting machine parameters on the performance characteristics of die casting process. Design of Experiments (DOE) with Response Surface Methodology (RSM) has been used to analyze the effect of effect of input parameters and their interaction on the response and further used to develop nonlinear input-output relationships. Die casting machine parameters, namely, fast shot velocity, slow shot to fast shot change over point, intensification pressure and holding time have been considered as the input variables. The quality characteristics of the cast product were determined by porosity, hardness and surface rough roughness (output/responses). Design of experiments has been used to plan the experiments and analyze the impact of variables on the quality of casting. On the other-hand Response Surface Methodology (Central Composite Design) is utilized to develop non-linear input-output relationships (regression models). The developed regression models have been tested for their statistical adequacy through ANOVA test. The practical usefulness of these models has been tested with some test cases. These models can be used to make the predictions about different quality characteristics, for the known set of die casting machine parameters, without conducting the experiments.

Kittur, Jayant K.; Herwadkar, T. V. [KLS Gogte Institute of Technology, Belgaum -590 008, Karnataka (India); Parappagoudar, M. B. [Chhatrapati Shivaji Institute of Technology, Durg (C.G)-491001 (India)

2010-10-26

34

Barium phosphate conversion coating on die-cast AZ91D magnesium alloy  

Microsoft Academic Search

Poor corrosion resistance limits the application of magnesium alloys. Conversion coating is widely used to protect magnesium alloys because of easy operation and low cost. A novel conversion coating on die-cast AZ91D magnesium alloy containing barium salts was studied. The optimum concentrations of Ba(NO3)2, Mn(NO3)2 and NH4H2PO4 are 25 g\\/L, 15 mL\\/L and 20 g\\/L, respectively, based on orthogonal test

Feng LIU; Da-yong SHAN; En-hou HAN; Chang-sheng LIU

2008-01-01

35

Secondary Al-Si-Mg High-pressure Die Casting Alloys with Enhanced Ductility  

NASA Astrophysics Data System (ADS)

Al-Si-Mg-based secondary cast alloys are attractive candidates for thin-walled high-pressure die castings for applications in the transport industry. The present study investigates the effect of manganese additions at high cooling rates on microstructure, mechanical properties, and on the dominating fracture mechanisms of alloy AlSi10Mg with an elevated iron concentration. Systematic variations of the Mn content from 0.20 to 0.85 wt pct at a constant Fe content of 0.55 wt pct illustrate the key changes in type, phase fraction, and shape of the Fe-containing intermetallic phases, and the corresponding influence on the alloy's ductility. For high-pressure die casting (HPDC), an optimal range of the Mn content between 0.40 and 0.60 wt pct, equivalent to a Mn/Fe ratio of approximately 1, has been identified. At these Mn and Fe contents, the high cooling rates obtained in HPDC result in the formation of fine and homogeneously distributed ?-Al15(Fe,Mn)3Si2 phase, and crack initiation is transferred from AlFeSi intermetallics to eutectic silicon. The study interprets the microstructure-property relationship in the light of thermodynamic calculations which reveal a significant increase in undercooling of the ?-Al15(Fe,Mn)3Si2 phase with increased Mn content. It concludes that the interdependence of the well-defined Mn/Fe ratio and the high cooling rate in HPDC can generate superior ductility in secondary AlSi10Mg cast alloys.

Bösch, Dominik; Pogatscher, Stefan; Hummel, Marc; Fragner, Werner; Uggowitzer, Peter J.; Göken, Mathias; Höppel, Heinz Werner

2015-03-01

36

Energy Saving Melting and Revert Reduction Technology (E-SMARRT): Development of Surface Engineered Coating Systems for Aluminum Pressure Die Casting Dies: Towards a 'Smart' Die Coating  

SciTech Connect

The main objective of this research program was to design and develop an optimal coating system that extends die life by minimizing premature die failure. In high-pressure aluminum die-casting, the die, core pins and inserts must withstand severe processing conditions. Many of the dies and tools in the industry are being coated to improve wear-resistance and decrease down-time for maintenance. However, thermal fatigue in metal itself can still be a major problem, especially since it often leads to catastrophic failure (i.e. die breakage) as opposed to a wear-based failure (parts begin to go out of tolerance). Tooling costs remain the largest portion of production costs for many of these parts, so the ability prevent catastrophic failures would be transformative for the manufacturing industry.The technology offers energy savings through reduced energy use in the die casting process from several factors, including increased life of the tools and dies, reuse of the dies and die components, reduction/elimination of lubricants, and reduced machine down time, and reduction of Al solder sticking on the die. The use of the optimized die coating system will also reduce environmental wastes and scrap parts. Current (2012) annual energy saving estimates, based on initial dissemination to the casting industry in 2010 and market penetration of 80% by 2020, is 3.1 trillion BTU's/year. The average annual estimate of CO2 reduction per year through 2020 is 0.63 Million Metric Tons of Carbon Equivalent (MM TCE).

Dr. John J. Moore; Dr. Jianliang Lin,

2012-07-31

37

Development of an Innovative Laser-Assisted Coating Process for Extending Lifetime of Metal Casting Dies. Final Report  

SciTech Connect

Die casting dies used in the metal casting industry fail due to thermal fatigue cracking accompanied by the presence of residual tensile stresses, corrosion, erosion and wear of die surfaces. This phase 1 SBIR Final Report summarize Karta Technologies research involving the development of an innovative laser coating technology for metal casting dies. The process involves depositing complex protective coatings of nanocrystalline powders of TiC followed by a laser shot peening. The results indicate a significant improvement in corrosion and erosion resistance in molten aluminum for H13 die casting die steels. The laser-coated samples also showed improved surface finish, a homogeneous and uniform coating mircrostructure. The technology developed in this research can have a significant impact on the casting industry by saving the material costs involved in replacing dies, reducing downtime and improving the quality.

Madhav Rao Gonvindaraju

1999-10-18

38

High Density Die Casting (HDDC): new frontiers in the manufacturing of heat sinks  

NASA Astrophysics Data System (ADS)

Finding a good solution for thermal management problems is every day more complex. due to the power density and the required performances. When a solution suitable for high volumes is needed. die-casting and extrusion are the most convenient technologies. However designers have to face the well-known limitations for those processes. High Density Die Casting (HDDC) is a process under advanced development. in order to overcome the extrusion and traditional die casting limits by working with alloys having much better thermal performances than the traditional die-casting process. while keeping the advantages of a flexible 3D design and a low cost for high volumes. HDDC offers the opportunity to design combining different materials (aluminium and copper. aluminium and stainless steel) obtaining a structure with zero porosity and overcoming some of die-casting limits. as shown in this paper. A dedicated process involving embedded heat pipes is currently under development in order to offer the possibility to dramatically improve the heat spreading.

Sce, Andrea; Caporale, Lorenzo

2014-07-01

39

Distortion and Residual Stress in High-Pressure Die Castings: Simulation and Measurements  

NASA Astrophysics Data System (ADS)

Two individual high-pressure die casting geometries were developed to study the influence of process parameters and alloy composition on the distortion behavior of aluminum alloy castings. These geometries, a stress lattice and a V-shaped lid, tend to form residual stress due to a difference in wall thickness and a deliberate massive gating system. Castings were produced from two alloys: AlSi12(Fe) and AlSi10MnMg. In the experimental castings, the influence of important process parameters such as die temperature, ejection time, and cooling regime was examined. The time evolution of process temperatures was measured using thermal imaging. Subsequent to casting, distortion was measured by means of a tactile measuring device at ambient temperatures. The measured results were compared against a numerical process and stress simulations of the casting, ejection, and cooling process using the commercial finite element method software ANSYS Workbench. The heat transfer coefficients were adapted to the temperature distributions of the die, and the castings were observed by thermal imaging. A survey of the results of the comparison between simulation and experiment is given for both alloys.

Hofer, P.; Kaschnitz, E.; Schumacher, P.

2014-09-01

40

Defect Band Characteristics in Mg-Al and Al-Si High-Pressure Die Castings  

Microsoft Academic Search

Bands of positive macrosegregation and porosity commonly follow the surface contour of components produced by high-pressure\\u000a die casting (HPDC). In this article, Al alloy AlSi7Mg and Mg alloys AZ91 and AM60 were cast into tensile test bars using cold-chamber\\u000a (cc) HPDC. Microstructural characterization revealed that externally solidified crystals (ESCs) are not necessary for defect\\u000a band formation, and that defect bands

C. M. Gourlay; H. I. Laukli; A. K. Dahle

2007-01-01

41

Defect Band Characteristics in Mg-Al and Al-Si High-Pressure Die Castings  

Microsoft Academic Search

Bands of positive macrosegregation and porosity commonly follow the surface contour of components produced by high-pressure die casting (HPDC). In this article, Al alloy AlSi7Mg and Mg alloys AZ91 and AM60 were cast into tensile test bars using cold-chamber (cc) HPDC. Microstructural characterization revealed that externally solidified crystals (ESCs) are not necessary for defect band formation, and that defect bands

C. M. Gourlay; H. I. Laukli; A. K. Dahle

2007-01-01

42

Low-strain plasticity in a high pressure die cast Mg–Al alloy  

Microsoft Academic Search

The Kocks–Mecking method was used to compare the strain-hardening behavior at low strains of high pressure die cast Mg-9 mass% Al alloy and gravity cast fine grained pure Mg specimens. The alloy specimens exhibited a rounded flow curve in contrast with the pure metal's for which macroscopic yielding occurred at a well-defined stress. Microhardness mapping of the cross-section of an

K Vanna Yang; C H Cáceres; A V Nagasekhar; M A Easton

2012-01-01

43

Qualitative Reasoning for Additional Die Casting Applications  

SciTech Connect

If manufacturing incompatibility of a product can be evaluated at the early product design stage, the designers can modify their design to reduce the effect of potential manufacturing problems. This will result in fewer manufacturing problems, less redsign, less expensive tooling, lower cost, better quality, and shorter development time. For a given design, geometric reasoning can predict qualitatively the behaviors of a physical manufacturing process by representing and reasoning with incomplete knowledge of the physical phenomena. It integrates a design with manufacturing processes to help designers simultaneously consider design goals and manufacturing constraints during the early design stage. The geometric reasoning approach can encourage design engineers to qualitatively evaluate the compatibility of their design with manufacturing limitations and requirements.

R. Allen Miller; Dehua Cui; Yuming Ma

2003-05-28

44

Simple visualization techniques for die casting part and die design. Final report, July 1, 1995--September 30, 1997  

SciTech Connect

The objective of this work was to develop and test die casting design evaluation techniques based on the visualization of geometric data that is related to potential defects of problems. Specifically, thickness information is used to provide insight into potential thermal problems in the part and die. Distance from the gate and a special type of animation of the fill pattern is used to provide an assessment of gate, vent and overflow locations. Techniques have been developed to convert part design information in the form of STL files to a volume-based representation called a voxel model. The use of STL files makes the process CAD system independent. Once in voxel form, methods that were developed in this work are used to identify thick regions in the part, thin regions in the part and/or die, distance from user specified entry locations (gates), and the qualitative depiction of the fill pattern. The methods were tested with a prototype implementation on the UNIX platform. The results of comparisons with numerical simulation and field reported defects were surprisingly good. The fill-related methods were also compared against short-shots and a water analog study using high speed video. The report contains the results of the testing plus detailed background material on the construction of voxel models, the methods used for displaying results, and the computational geometric reasoning methods used to create die casting-related information form the voxel model for display to the user.

Miller, R.A.; Lu, S.C.; Rebello, A.B.

1998-05-01

45

Simple visualization techniques for die casting part and die design. Final report, July 1, 1995--September 30, 1997  

SciTech Connect

The objective of this work was to develop and test die casting design evaluation techniques based on the visualization of geometric data that is related to potential defects of problems. Specifically, thickness information is used to provide insight into potential thermal problems in the part and die. Distance from the gate and a special type of animation of the fill pattern is used to provide an assessment of gate, vent and overflow locations. Techniques have been developed to convert part design information in the form of STL files to a volume-based representation called a voxel model. The use of STL files makes the process CAD system independent. Once in voxel form, methods that were developed in this work are used to identify thick regions in the part, thin regions in the part and/or die, distance from user specified entry locations (gates), and the qualitative depiction of the fill pattern. The methods were tested with a prototype implementation on the UNIX platform. The results of comparisons with numerical simulation and field reported defects were surprisingly good. The fill-related methods were also compared against short-shots and a water analog study using high speed video. The report contains the results of the testing plus detailed background material on the construction of voxel models, the methods used for displaying results, and the computational geometric reasoning methods used to create die casting-related information from the voxel model for display to the user.

Miller, R.A.; Lu, S.C.; Rebello, A.B.

1998-05-01

46

Final report to USAMP on the use of EBPVD in the light metal die casting industry  

SciTech Connect

This is the final report to the United States Automotive Materials Partnership (USAMP) on the use of Electron Beam Physical Vapor Deposition (EBPVD) to make rapid tooling for functional prototyping of metal mold processes. Historically this process has been successfully applied to the production of mold inserts for the plastics injection mold industry. Our approach for this project was to use the same technique to produce dies which could be used to make a few thousand light metal (aluminum and magnesium) prototype parts. The difficulty encountered in this project was that the requirements for the die casting industry, both in size and material requirements, were considerably more stringent than those encountered in the plastics injection industry. Consequently our technique, within the allotted time and budget constraints, was not able to meet the requirements set forth by USAMP. The remainder of this report is organized into five sections. The first discusses the technique in some detail while the second discusses a successful application. The third section discusses issues with this process while the fourth specifically discusses the work done in this project. The last is a short summary and conclusion section.

Heestand, G.M.

1996-02-02

47

Metallic Reinforcement of Direct Squeeze Die Casting Aluminum Alloys for Improved Strength and Fracture Resistance  

SciTech Connect

The utilization of aluminum die casting as enclosures where internal equipment is rotating inside of the casting and could fracture requires a strong housing to restrain the fractured parts. A typical example would be a supercharger. In case of a failure, unless adequately contained, fractured parts could injure people operating the equipment. A number of potential reinforcement materials were investigated. The initial work was conducted in sand molds to create experimental conditions that promote prolonged contact of the reinforcing material with molten aluminum. Bonding of Aluminum bronze, Cast iron, and Ni-resist inserts with various electroplated coatings and surface treatments were analyzed. Also toughening of A354 aluminum cast alloy by steel and stainless steel wire mesh with various conditions was analyzed. A practical approach to reinforcement of die cast aluminum components is to use a reinforcing steel preform. Such performs can be fabricated from steel wire mesh or perforated metal sheet by stamping or deep drawing. A hemispherical, dome shaped casting was selected in this investigation. A deep drawing die was used to fabricate the reinforcing performs. The tendency of aluminum cast enclosures to fracture could be significantly reduced by installing a wire mesh of austenitic stainless steel or a punched austenitic stainless steel sheet within the casting. The use of reinforcements made of austenitic stainless steel wire mesh or punched austenitic stainless steel sheet provided marked improvement in reducing the fragmentation of the casting. The best strengthening was obtained with austenitic stainless steel wire and with a punched stainless steel sheet without annealing this material. Somewhat lower results were obtained with the annealed punched stainless steel sheet. When the annealed 1020 steel wire mesh was used, the results were only slightly improved because of the lower mechanical properties of this unalloyed steel. The lowest results were obtained with unreinforced 356 aluminum casting. Good strength can be obtained with a sound die casting without any defects produced by squeeze casting. The use of higher pressure to produce the squeeze casting has been shown to increase the strength of a hemispherical dome casting. This dome shape casting has been produced both with and without reinforcement and tested to determine its pressure resistance under internal pressure of water. Only a slight improvement in strength could be determined because of water leaks at the seal between hemispherical dome and its flat supporting side. However, when the ability of the casting was tested under the compressive force of a plunger, the strengthening effect of wire mesh or sheet was evident. Higher loads to failure were obtained because of the reinforcement of the stainless steel wire and punched sheet. Rather than a sudden failure occurring, the reinforcement of the stainless steel wire or the punched hard stainless steel sheet held the material together and prevented any loss of the fractured casting to the surroundings. Unalloyed steel did not have the required strength or mechanical properties to increase the properties of the casting.

D. Schwam: J.F. Wallace: Y. Zhu: J.W. Ki

2004-10-01

48

Modelling the environmental impact of an aluminium pressure die casting plant and options for control  

Microsoft Academic Search

This study describes a model (MIKADO) to analyse options to reduce the environmental impact of aluminium die casting. This model will take a company perspective, so that it can be used as a decision-support tool for the environmental management of a plant. MIKADO can be used to perform scenario analyses to analyse the impact on the environment of different strategies,

Belmira Neto; Carolien Kroeze; Leen Hordijk; Carlos Costa

2008-01-01

49

Influence of Sludge Particles on the Tensile Properties of Die-Cast Secondary Aluminum Alloys  

NASA Astrophysics Data System (ADS)

The effects of sludge intermetallic particles on the mechanical properties of a secondary AlSi9Cu3(Fe) die-casting alloy have been studied. Different alloys have been produced by systematically varying the Fe, Mn, and Cr contents within the composition tolerance limits of the standard EN AC-46000 alloy. The microstructure shows primary ?-Al x (Fe,Mn,Cr) y Si z sludge particles, with polyhedral and star-like morphologies, although the presence of primary ?-Al5FeSi phase is also observed at the highest Fe:Mn ratio. The volume fraction of primary compounds increases as the Fe, Mn, and Cr contents increase and this can be accurately predicts from the Sludge Factor by a linear relationship. The sludge amount seems to not influence the size and the content of porosity in the die-cast material. Furthermore, the sludge factor is not a reliable parameter to describe the mechanical properties of the die-cast AlSi9Cu3(Fe) alloy, because this value does not consider the mutual interaction between the elements. In the analyzed range of composition, the design of experiment methodology and the analysis of variance have been used in order to develop a semi-empirical model that accurately predicts the mechanical properties of the die-cast AlSi9Cu3(Fe) alloys as function of Fe, Mn, and Cr concentrations.

Ferraro, Stefano; Timelli, Giulio

2014-12-01

50

Modeling of microstructure evolution of magnesium alloy during the high pressure die casting process  

NASA Astrophysics Data System (ADS)

Two important microstructure characteristics of high pressure die cast magnesium alloy are the externally solidified crystals (ESCs) and the fully divorced eutectic which form at the filling stage of the shot sleeve and at the last stage of solidification in the die cavity, respectively. Both of them have a significant influence on the mechanical properties and performance of magnesium alloy die castings. In the present paper, a numerical model based on the cellular automaton (CA) method was developed to simulate the microstructure evolution of magnesium alloy during cold-chamber high pressure die casting (HPDC) process. Modeling of dendritic growth of magnesium alloy with six-fold symmetry was achieved by defining a special neighbourhood configuration and calculating of the growth kinetics from complete solution of the transport equations. Special attention was paid to establish a nucleation model considering both of the nucleation of externally solidified crystals in the shot sleeve and the massive nucleation in the die cavity. Meanwhile, simulation of the formation of fully divorced eutectic was also taken into account in the present CA model. Validation was performed and the capability of the present model was addressed by comparing the simulated results with those obtained by experiments.

Wu, Mengwu; Xiong, Shoumei

2012-07-01

51

The effect of injection velocity on liquid segregation and mechanical properties in arm part fabricated by semi-solid die casting process  

Microsoft Academic Search

Semi-solid die casting of Al alloy is suitable for complicated large parts of near net shape without defect and excellent mechanical properties in comparison with conventional casting process. Die design for the product with high quality in semi-solid die casting is required to prevent micro porosity, inflow of oxidized substances, and liquid segregation. Therefore, shape and size of runner, position

C. G. Kang; P. K. Seo; S. S. Kang

2006-01-01

52

Energy Saving Melting and Revert Reduction Technology: Melting Efficiency in Die Casting Operations  

SciTech Connect

This project addressed multiple aspects of the aluminum melting and handling in die casting operations, with the objective of increasing the energy efficiency while improving the quality of the molten metal. The efficiency of melting has always played an important role in the profitability of aluminum die casting operations. Consequently, die casters need to make careful choices in selecting and operating melting equipment and procedures. The capital cost of new melting equipment with higher efficiency can sometimes be recovered relatively fast when it replaces old melting equipment with lower efficiency. Upgrades designed to improve energy efficiency of existing equipment may be well justified. Energy efficiency is however not the only factor in optimizing melting operations. Melt losses and metal quality are also very important. Selection of melting equipment has to take into consideration the specific conditions at the die casting shop such as availability of floor space, average quantity of metal used as well as the ability to supply more metal during peaks in demand. In all these cases, it is essential to make informed decisions based on the best available data.

David Schwam

2012-12-15

53

Development of materials for the rapid manufacture of die cast tooling  

NASA Astrophysics Data System (ADS)

The focus of this research is to develop a material composition that can be processed by rapid prototyping (RP) in order to produce tooling for the die casting process. Where these rapidly produced tools will be superior to traditional tooling production methods by offering one or more of the following advantages: reduced tooling cost, shortened tooling creation time, reduced man-hours for tool creation, increased tool life, and shortened die casting cycle time. By utilizing RP's additive build process and vast material selection, there was a prospect that die cast tooling may be produced quicker and with superior material properties. To this end, the material properties that influence die life and cycle time were determined, and a list of materials that fulfill these "optimal" properties were highlighted. Physical testing was conducted in order to grade the processability of each of the material systems and to optimize the manufacturing process for the downselected material system. Sample specimens were produced and microscopy techniques were utilized to determine a number of physical properties of the material system. Additionally, a benchmark geometry was selected and die casting dies were produced from traditional tool materials (H13 steel) and techniques (machining) and from the newly developed materials and RP techniques (selective laser sintering (SLS) and laser engineered net shaping (LENS)). Once the tools were created, a die cast alloy was selected and a preset number of parts were shot into each tool. During tool creation, the manufacturing time and cost was closely monitored and an economic model was developed to compare traditional tooling to RP tooling. This model allows one to determine, in the early design stages, when it is advantageous to implement RP tooling and when traditional tooling would be best. The results of the physical testing and economic analysis has shown that RP tooling is able to achieve a number of the research objectives, namely, reduce tooling cost, shorten tooling creation time, and reduce the man-hours needed for tool creation. Though identifying the appropriate time to use RP tooling appears to be the most important aspect in achieving successful implementation.

Hardro, Peter Jason

54

Prediction of Thermal Fatigue in Tooling for Die-casting Copper via Finite Element Analysis  

NASA Astrophysics Data System (ADS)

Recent research by the Copper Development Association (CDA) has demonstrated the feasibility of die-casting electric motor rotors using copper. Electric motors using copper rotors are significantly more energy efficient relative to motors using aluminum rotors. However, one of the challenges in copper rotor die-casting is low tool life. Experiments have shown that the higher molten metal temperature of copper (1085 °C), as compared to aluminum (660 °C) accelerates the onset of thermal fatigue or heat checking in traditional H-13 tool steel. This happens primarily because the mechanical properties of H-13 tool steel decrease significantly above 650 °C. Potential approaches to mitigate the heat checking problem include: 1) identification of potential tool materials having better high temperature mechanical properties than H-13, and 2) reduction of the magnitude of cyclic thermal excursions experienced by the tooling by increasing the bulk die temperature. A preliminary assessment of alternative tool materials has led to the selection of nickel-based alloys Haynes 230 and Inconel 617 as potential candidates. These alloys were selected based on their elevated temperature physical and mechanical properties. Therefore, the overall objective of this research work was to predict the number of copper rotor die-casting cycles to the onset of heat checking (tool life) as a function of bulk die temperature (up to 650 °C) for Haynes 230 and Inconel 617 alloys. To achieve these goals, a 2D thermo-mechanical FEA was performed to evaluate strain ranges on selected die surfaces. The method of Universal Slopes (Strain Life Method) was then employed for thermal fatigue life predictions.

Sakhuja, Amit; Brevick, Jerald R.

2004-06-01

55

Casting Technology.  

ERIC Educational Resources Information Center

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)

Wright, Michael D.; And Others

1992-01-01

56

Fabrication of glass photonic crystal fibers with a die-cast process  

NASA Astrophysics Data System (ADS)

We demonstrate a novel method for the fabrication of glass photonic crystal fibers (PCFs) with a die-cast process. SF6 glass is used as the material for PCFs, and the die is made of heat-resisting alloy steel, whose inner structure matches the PCF's structure. The die is put vertically in the vessel with SF6 glass, and the vacuum hose is attached to the top of the die. The die and glass are put in the furnace to heat at 870 K. The die is slowly filled with the softening glass under vacuum conduction until it is full. It is kept in the furnace to anneal at a rate of 20 K/h to remove the thermal stress that could lead to cracks. The outer tube of the die is taken apart when its temperature is close to room temperature, and the fused glass bundle is etched in an acidic solution to remove the heat-resisting alloy steel rods. Thus, the etched bundle is ready to use as a PCF preform. The PCF is observed in the generation of a supercontinuum, with the flat plateau in the spectrum of the output emission stretching from 400 to 1400 nm by experimental measurement. The transmission loss is 0.2-0.3 dB/m at wavelengths of 420-900 nm.

Guiyao, Zhou; Zhiyun, Hou; Shuguang, Li; Lantian, Hou

2006-06-01

57

Fabrication of glass photonic crystal fibers with a die-cast process.  

PubMed

We demonstrate a novel method for the fabrication of glass photonic crystal fibers (PCFs) with a die-cast process. SF6 glass is used as the material for PCFs, and the die is made of heat-resisting alloy steel, whose inner structure matches the PCF's structure. The die is put vertically in the vessel with SF6 glass, and the vacuum hose is attached to the top of the die. The die and glass are put in the furnace to heat at 870 K. The die is slowly filled with the softening glass under vacuum conduction until it is full. It is kept in the furnace to anneal at a rate of 20 K/h to remove the thermal stress that could lead to cracks. The outer tube of the die is taken apart when its temperature is close to room temperature, and the fused glass bundle is etched in an acidic solution to remove the heat-resisting alloy steel rods. Thus, the etched bundle is ready to use as a PCF preform. The PCF is observed in the generation of a supercontinuum, with the flat plateau in the spectrum of the output emission stretching from 400 to 1400 nm by experimental measurement. The transmission loss is 0.2-0.3 dB/m at wavelengths of 420-900 nm. PMID:16778953

Guiyao, Zhou; Zhiyun, Hou; Shuguang, Li; Lantian, Hou

2006-06-20

58

Development of a novel hypereutectic aluminum-siliconmagnesium alloy for die casting  

Microsoft Academic Search

A novel hypereutectic die casting Al-Si-Mg alloy with relatively high Mg content was developed. The optimized microstructure\\u000a of the alloy is characterized by a fine dispersion of eutectic Si and Mg2Si particles in an ?-Al matrix which is devoid of primary silicon particles. Of the several modifiers used to refine the coarse\\u000a morphology of the Mg2Si particles, an optimum combination

A. Mandal; M. M. Makhlouf

2009-01-01

59

Microstructure and mechanical behavior of die casting AZ91D-Fly ash cenosphere composites  

Microsoft Academic Search

The feasibility of incorporating fly ash cenospheres in die cast magnesium alloy has been demonstrated. The effects of fly ash cenosphere additions on the microstructure and some of the salient physical and mechanical properties of magnesium alloy (AZ91D) metal matrix composites were investigated. The control AZ91D alloy and associated composites, containing 5, 10, and 15wt.% of fly ash cenospheres (added),

P. K. Rohatgi; A. Daoud; B. F. Schultz; T. Puri

2009-01-01

60

Numerical Simulations of Jet Break-up Phenomena for the High Pressure Die Casting Process  

SciTech Connect

In High Pressure Die Casting a molten metal is injected through a thin gate into the cast cavity. High injection pressures and high gate velocities create atomization phenomena which can negatively affect the final quality of the cast. In order to control atomization process it is essential to understand the atomization patterns and the two-phase flowfield that exist at the gate exit. In the present work, 2D numerical simulations of the flow of molten Magnesium through a high aspect-ratio rectangular gate are performed using a water analogue for an open and closed cavity. The numerical simulations made use of VOF-type (Eulerian) physical models and Lagrangian models. Further, a sub-grid scale model was implemented that, in conjunction with VOF-type equations can efficiently predict the general atomization pattern without the need for high-resolution grids. The numerical results were compared to experimental data for validation.

Sabau, Adrian S [ORNL

2006-01-01

61

APPLICATION OF COMPUTATIONAL FLUID DYNAMICS TO STEEL REFINING AND CASTING PROCESSES  

E-print Network

1 APPLICATION OF COMPUTATIONAL FLUID DYNAMICS TO STEEL REFINING AND CASTING PROCESSES Lifeng Zhang ladles, the continuous casting tundish, continuous casting mold and strand, and steel ingot casting, Continuous Casting, Ingot Casting, Inclusions INTRODUCTION Fluid flow during steelmaking, steel refining

Thomas, Brian G.

62

Development of Advanced Coating Techniques for Highly-durable Casting Dies  

NASA Astrophysics Data System (ADS)

In order to improve the durability of aluminum die-casting molds, we applied microstructure-controlled PVD coating techniques. Single-layer and multilayer films consisting of chromium nitride (CrN) or titanium aluminum nitride (TiAlN) were prepared using an ion plating process. Structures of multilayer films were observed using transmission electron microscopy. Pin-shaped mold steel specimens coated with each of the films were soaked in the molten aluminum alloy at 953 K different periods of time, and the amount of weight loss due to erosion was evaluated. The weight losses for the multilayer CrN and TiAlN specimens were found to be less than those for the single-layer specimens. As a practical test, five specimens of core pins used in aluminum die casting of automobile parts were coated with multilayer films, and the number of maintenance operations required to remove aluminum alloy remaining on the specimen surfaces after several thousand castings was counted and compared with six control specimens (core pins treated using a commercial salt bath diffusion process). The number of maintenance operations for CrN- and TiAlN-based multilayer-coated core pins was found to be lower than for the control specimens.

Tanaka, S.; Takagi, M.; Mano, T.

2013-03-01

63

Low-strain plasticity in a high pressure die cast Mg-Al alloy  

NASA Astrophysics Data System (ADS)

The Kocks-Mecking method was used to compare the strain-hardening behavior at low strains of high pressure die cast Mg-9 mass% Al alloy and gravity cast fine grained pure Mg specimens. The alloy specimens exhibited a rounded flow curve in contrast with the pure metal's for which macroscopic yielding occurred at a well-defined stress. Microhardness mapping of the cross-section of an alloy specimen showed a surface layer, or skin, with hardness values ˜20 HV above those of the centre or core region. On the assumption that the core strain hardens at the same rate as the pure Mg specimen, it was estimated that ˜20% of the alloy specimen's cross-section was still elastic when the core reached full plasticity. The micromechanics of the elasto-plastic transition in the alloy specimens are discussed.

Vanna Yang, K.; Cáceres, C. H.; Nagasekhar, A. V.; Easton, M. A.

2012-03-01

64

The Effects of Microstructure Heterogeneities and Casting Defects on the Mechanical Properties of High-Pressure Die-Cast AlSi9Cu3(Fe) Alloys  

NASA Astrophysics Data System (ADS)

Detailed investigations of the salient microstructural features and casting defects of the high-pressure die-cast (HPDC) AlSi9Cu3(Fe) alloy are reported. These characteristics are addressed to the mechanical properties and reliability of separate HPDC tensile bars. Metallographic and image analysis techniques have been used to quantitatively examine the microstructural changes throughout the tensile specimen. The results indicate that the die-cast microstructure consists of several microstructural heterogeneities such as positive eutectic segregation bands, externally solidified crystals (ESCs), cold flakes, primary Fe-rich intermetallics (sludge), and porosities. In addition, it results that sludge particles, gas porosity, as well as ESCs, and cold flakes are concentrated toward the casting center while low porosity and fine-grained structure is observed on the surface layer of the castings bars. The local variation of the hardness along the cross section as well as the change of tensile test results as a function of gage diameter of the tensile bars seem to be ascribed to the change of porosity content, eutectic fraction, and amount of sludge. Further, this behavior reflects upon the reliability of the die-cast alloy, as evidenced by the Weibull statistics.

Timelli, Giulio; Fabrizi, Alberto

2014-11-01

65

Cast Aluminum Alloy for High Temperature Applications  

NASA Technical Reports Server (NTRS)

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.

Lee, Jonathan A.

2003-01-01

66

40 CFR 420.60 - Applicability; description of the continuous casting subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the continuous casting subcategory. 420.60 ...MANUFACTURING POINT SOURCE CATEGORY Continuous Casting Subcategory § 420.60 Applicability; description of the continuous casting subcategory. The...

2010-07-01

67

Flow analysis and validation of numerical modelling for a thin walled high pressure die casting using SPH  

NASA Astrophysics Data System (ADS)

High pressure die casting (HPDC) is an important process for high throughput manufacturing of complex shaped metallic components. The flow involves significant fragmentation and spray formation as the high pressure liquid jets into the die from the gate system. An important class of die cast components is one with large areas of thin walls. An example of this is the chassis of the laptop computer. Computational modelling provides an opportunity to both better understand the filling process and to optimize the runner, gates, flash overs and venting systems for the die. SPH has previously been found to be very suitable for predicting HPDC for bulkier automotive components. The modelling challenges arising from the very thin sections and the many flow paths in a laptop chassis require careful validation. A water analogue experiment is used to validate the predictions of the SPH model for this representative thin walled casting. SPH predictions are used to understand and characterise the filling process. Finally, comparison of flow lines visible in an etched finished casting with the high speed flow paths in the final filled SPH model show very strong agreement. Together these demonstrate that such an SPH model is able to capture substantial detail from both the water analogue system and the actual casting process and is very suitable for simulating these types of complex thin walled castings.

Cleary, Paul W.; Savage, Gary; Ha, Joseph; Prakash, Mahesh

2014-09-01

68

An evaluation of direct pressure sensors for monitoring the aluminum die casting process  

SciTech Connect

This study was conducted as part of the US Department of Energy (DOE) sponsored project Die Cavity Instrumentation. One objective of that project was to evaluate thermal, pressure, and gas flow process monitoring sensors in or near the die cavity as a means of securing improved process monitoring and control and better resultant part quality. The objectives of this thesis are to (1) evaluate a direct cavity pressure sensor in a controlled production campaign at the GM Casting Advanced Development Center (CADC) at Bedford, Indiana; and (2) develop correlations between sensor responses and product quality in terms of the casting weight, volume, and density. A direct quartz-based pressure sensor developed and marked by Kistler Instrument Corp. was acquired for evaluating as an in-cavity liquid metal pressure sensor. This pressure sensor is designed for use up to 700 C and 2,000 bars (29,000 psi). It has a pressure overload capacity up to 2,500 bars (36,250 psi).

Zhang, X.

1997-12-31

69

Application of New Feeding Rules To Risering of Steel Castings  

E-print Network

1 Application of New Feeding Rules To Risering of Steel Castings Doug Smith , Tony Faivre , Shouzhu., Hardin, R.A., and Beckermann, C., "Application of New Feeding Rules to Risering of Steel Castings The importance of investigating and improving the guidelines for risering and feeding steel castings is clear

Beckermann, Christoph

70

Fabrication process analysis and experimental verification for aluminum bipolar plates in fuel cells by vacuum die-casting  

NASA Astrophysics Data System (ADS)

There are various methods for the fabrication of bipolar plates, but these are still limited to machining and stamping processes. High-pressure die casting (HPDC) is an ideal process for the manufacture of bipolar plates This study aims to investigate the formability of bipolar plates for polymer electrolyte membrane fuel cells (PEMFCs) fabricated by vacuum HPDC of an Al-Mg alloy (ALDC6). The cavity of the mold consisted of a thin-walled plate (200 mm × 200 mm × 0.8 mm) with a layer of serpentine channel (50 mm × 50 mm). The location and direction of the channel in the final mold design was determined by computational simulation (MAGMA soft). In addition, simulation results for different conditions of plunger stroke control were compared to those from actual die-casting experiments. Under a vacuum pressure of 35 kPa and for injection speeds of 0.3 and 2.5 m s-1 in the low and high speed regions, respectively, the samples had few casting defects. In addition, the hardness was higher and porosity in microstructure was less than those of the samples made under other injection speed conditions. In case of thin-walled plates, vacuum die casting is beneficial in terms of formability compared to conventional die casting.

Jin, Chul Kyu; Kang, Chung Gil

2011-10-01

71

MACHINING ELIMINATION THROUGH APPLICATION OF THREAD FORMING FASTENERS IN NET SHAPED CAST HOLES  

SciTech Connect

The ultimate objective of this work was to eliminate approximately 30% of the machining performed in typical automotive engine and transmission plants by using thread forming fasteners in as-cast holes of aluminum and magnesium cast components. The primary issues at the source of engineers���������������¢�������������������������������� reluctance to implementing thread forming fasteners in lightweight castings are: * Little proof of consistency of clamp load vs. input torque in either aluminum or magnesium castings. * No known data to understand the effect on consistency of clamp load as casting dies wear. The clamp load consistency concern is founded in the fact that a portion of the input torque used to create clamp load is also used to create threads. The torque used for thread forming may not be consistent due to variations in casting material, hole size and shape due to tooling wear and process variation (thermal and mechanical). There is little data available to understand the magnitude of this concern or to form the basis of potential solutions if the range of clamp load variation is very high (> +/- 30%). The range of variation that can be expected in as-cast hole size and shape over the full life cycle of a high pressure die casting die was established in previous work completed by Pacific Northwest National Laboratory, (PNNL). This established range of variation was captured in a set of 12 cast bosses by designing core pins at the size and draft angles identified in the sited previous work. The cast bosses were cut into ���������������¢��������������������������������nuts���������������¢������������������������������� that could be used in the Ford Fastener Laboratory test-cell to measure clamp load when a thread forming fastener was driven into a cast nut. There were two sets of experiments run. First, a series of cast aluminum nuts were made reflecting the range of shape and size variations to be expected over the life cycle of a die casting die. Taptite thread forming fasteners, (a widely used thread forming fastener suitable for aluminum applications), were driven into the various cored, as-cast nuts at a constant input torque and resulting clamp loads were recorded continuously. The clamp load data was used to determine the range of clamp loads to be expected. The bolts were driven to failure. The clamp load corresponding to the target input of 18.5 Nm was recorded for each fastener. In a like fashion, a second set of experiments were run with cast magnesium nuts and ALtracs thread forming fasteners, (a widely used thread forming fastener suitable for magnesium applications). Again all clamp loads were recorded and analyzed similarly to the Taptites in aluminum cast nuts. Results from previous work performed on the same test cell for a Battelle project using standard M8 bolts into standard M8 nuts were included as a comparator for a standard bolt and nut application. The results for the thread forming fasteners in aluminum cast holes were well within industry expectations of +/- 30% for out of the box and robustness range te

Cleaver, Ryan J.; Cleaver, Todd H.; Talbott, Richard

2012-05-02

72

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

Code of Federal Regulations, 2013 CFR

...false Applicability; description of the zinc casting subcategory. 464.40 Section...MOLDING AND CASTING POINT SOURCE CATEGORY Zinc Casting Subcategory § 464.40 Applicability; description of the zinc casting subcategory. The...

2013-07-01

73

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

Code of Federal Regulations, 2012 CFR

...false Applicability; description of the zinc casting subcategory. 464.40 Section...MOLDING AND CASTING POINT SOURCE CATEGORY Zinc Casting Subcategory § 464.40 Applicability; description of the zinc casting subcategory. The...

2012-07-01

74

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

Code of Federal Regulations, 2014 CFR

...false Applicability; description of the zinc casting subcategory. 464.40 Section...MOLDING AND CASTING POINT SOURCE CATEGORY Zinc Casting Subcategory § 464.40 Applicability; description of the zinc casting subcategory. The...

2014-07-01

75

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

Code of Federal Regulations, 2011 CFR

...false Applicability; description of the zinc casting subcategory. 464.40 Section...MOLDING AND CASTING POINT SOURCE CATEGORY Zinc Casting Subcategory § 464.40 Applicability; description of the zinc casting subcategory. The...

2011-07-01

76

40 CFR 464.20 - Applicability; description of the copper casting subcategory.  

Code of Federal Regulations, 2010 CFR

... Applicability; description of the copper casting subcategory. 464.20 Section...MOLDING AND CASTING POINT SOURCE CATEGORY Copper Casting Subcategory § 464.20 Applicability; description of the copper casting subcategory. The...

2010-07-01

77

40 CFR 464.20 - Applicability; description of the copper casting subcategory.  

Code of Federal Regulations, 2011 CFR

... Applicability; description of the copper casting subcategory. 464.20 Section...MOLDING AND CASTING POINT SOURCE CATEGORY Copper Casting Subcategory § 464.20 Applicability; description of the copper casting subcategory. The...

2011-07-01

78

40 CFR 464.20 - Applicability; description of the copper casting subcategory.  

Code of Federal Regulations, 2012 CFR

... Applicability; description of the copper casting subcategory. 464.20 Section...MOLDING AND CASTING POINT SOURCE CATEGORY Copper Casting Subcategory § 464.20 Applicability; description of the copper casting subcategory. The...

2012-07-01

79

40 CFR 464.20 - Applicability; description of the copper casting subcategory.  

Code of Federal Regulations, 2013 CFR

... Applicability; description of the copper casting subcategory. 464.20 Section...MOLDING AND CASTING POINT SOURCE CATEGORY Copper Casting Subcategory § 464.20 Applicability; description of the copper casting subcategory. The...

2013-07-01

80

40 CFR 464.20 - Applicability; description of the copper casting subcategory.  

Code of Federal Regulations, 2014 CFR

... Applicability; description of the copper casting subcategory. 464.20 Section...MOLDING AND CASTING POINT SOURCE CATEGORY Copper Casting Subcategory § 464.20 Applicability; description of the copper casting subcategory. The...

2014-07-01

81

40 CFR 464.10 - Applicability; description of the aluminum casting subcategory.  

Code of Federal Regulations, 2012 CFR

...Applicability; description of the aluminum casting subcategory. 464.10...AND CASTING POINT SOURCE CATEGORY Aluminum Casting Subcategory § 464.10 Applicability; description of the aluminum casting subcategory. The...

2012-07-01

82

40 CFR 464.10 - Applicability; description of the aluminum casting subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the aluminum casting subcategory. 464.10...AND CASTING POINT SOURCE CATEGORY Aluminum Casting Subcategory § 464.10 Applicability; description of the aluminum casting subcategory. The...

2010-07-01

83

40 CFR 464.10 - Applicability; description of the aluminum casting subcategory.  

Code of Federal Regulations, 2011 CFR

...Applicability; description of the aluminum casting subcategory. 464.10...AND CASTING POINT SOURCE CATEGORY Aluminum Casting Subcategory § 464.10 Applicability; description of the aluminum casting subcategory. The...

2011-07-01

84

40 CFR 464.10 - Applicability; description of the aluminum casting subcategory.  

Code of Federal Regulations, 2013 CFR

...Applicability; description of the aluminum casting subcategory. 464.10...AND CASTING POINT SOURCE CATEGORY Aluminum Casting Subcategory § 464.10 Applicability; description of the aluminum casting subcategory. The...

2013-07-01

85

40 CFR 464.10 - Applicability; description of the aluminum casting subcategory.  

Code of Federal Regulations, 2014 CFR

...Applicability; description of the aluminum casting subcategory. 464.10...AND CASTING POINT SOURCE CATEGORY Aluminum Casting Subcategory § 464.10 Applicability; description of the aluminum casting subcategory. The...

2014-07-01

86

A summary of special coatings projects conducted in support of the Die Casting Program  

SciTech Connect

The usefulness of various kinds of coatings to the die casting program has been studied. This work includes heat transfer and fluid flow calculations, as well as experimental work, to examine the feasibility and characteristics of various types of coatings. Calculations include the effect of surface roughness on fluid flow, conductance as a function of coating thickness, conductivity as a function of coating porosity, and solidification and possible remelting of microspheres of metal. In each case, the model is described and the results are presented. Experimental work involved evaluating the relative insulating value of various coatings and an analysis of commercial flame-sprayed coatings, low-density coatings, and release coatings. In each case, description of the experimental arrangement is given and the results are described. 5 refs., 28 figs., 6 tabs.

Selle, J.E.

1988-09-12

87

The study of flow pattern and phase-change problem in die casting process  

NASA Technical Reports Server (NTRS)

The flow pattern and solidification phenomena in die casting process have been investigated in the first phase study. The flow pattern in filling process is predicted by using a VOF (volume of fluid) method. A good agreement with experimental observation is obtained for filling the water into a die cavity with different gate geometry and with an obstacle in the cavity. An enthalpy method has been applied to solve the solidification problem. By treating the latent heat implicitly into the enthalpy instead of explicitly into the source term, the CPU time can be reduced at least 20 times. The effect of material properties on solidification fronts is tested. It concludes that the dependence of properties on temperature is significant. The influence of the natural convection over the diffusion has also been studied. The result shows that the liquid metal solidification phenomena is diffusion dominant, and the natural convection can affect the shape of the interface. In the second phase study, the filling and solidification processes will be considered simultaneously.

Wang, T. S.; Wei, H.; Chen, Y. S.; Shang, H. M.

1996-01-01

88

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

SciTech Connect

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.

NONE

1994-11-01

89

Influence of the fabrication process on the functionality of piezoceramic patch transducers embedded in aluminum die castings  

NASA Astrophysics Data System (ADS)

Piezoceramic patch transducers are integrated into aluminum components using high-pressure die casting. Expanded metal has proven suitable as a supporting structure for placing the patch transducers inside the die cavity and for stabilization during the injection of molten metal. However, difficulties arise when the transducers are positioned off the neutral axis within the wall of the casting. Numerical simulations of the die filling are performed to analyse the evolution of the integration process. The asymmetric infiltration of the supporting structure is identified as the major factor contributing to the formation of cracks and perforations inside the piezoceramic transducer. By means of measurements and numerical calculations of the electrical impedance of the transducer, a close relation is established between mechanical damage patterns observed in radiographs of the patch transducers and loss of performance.

Klassen, Alexander; Rübner, Matthias; Ilg, Jürgen; Rupitsch, Stefan J.; Lerch, Reinhard; Singer, Robert F.; Körner, Carolin

2012-11-01

90

Improved Life of Die Casting Dies of H13 Steel by Attaining Improved Mechanical Properties and Distortion Control During Heat Treatment  

SciTech Connect

The ultimate goal of this project is to increase die casting die life by using fast enough quenching rates to obtain good toughness and fatigue resistance in premium grade H-13 steel dies. The main tasks of the project were to compile a database on physical and mechanical properties of H-13; conduct gas quenching experiments to determine cooling rates of dies in difference vacuum furnaces; measure the as-quenched distortion of dies and the residual stresses; generate finite element analysis models to predict cooling rates, distortion, and residual stress of gas quenched dies; and establish rules and create PC-based expert system for prediction of cooling rates, distortion, and residual stress in vacuum/gas quenched H-13 dies. Cooling curves during gas quenching of H-13 blocks and die shapes have been measured under a variety of gas pressure. Dimensional changes caused by the gas quenching processes have been determined by accurate mapping of all surfaces with coordinate measuring machines before and after the quench. Residual stresses were determined by the ASTM E837 hole-drilling strain gage method. To facilitate the computer modeling work, a comprehensive database of H-13 mechanical and physical properties has been compiled. Finite element analysis of the heat treated shapes has been conducted using the TRAST/ABAQUS codes. There is a good fit between the predicted and measured distortion contours. However, the magnitude of the predicted distortion and residual stresses does not match well the measured values. Further fine tuning of the model is required before it can be used to predict distortion and residual stress in a quantitative manner. This last step is a prerequisite to generating rules for a reliable expert system.

J. F. Wallace; D. Schwam

1998-10-01

91

A comparative evaluation of application techniques of a paint-on die spacer in grooves: an in vitro study.  

PubMed

The use of paint-on die spacer to improve the seating of casting has become quite popular in the recent years. The generally accepted range of paint-on die spacer is approximately 20-40 ?m, which suggests a range of tolerance. The painting of the retentive grooves with die spacer has always been a subject of debate. The primary purpose of this study was to determine if there was a tendency for the paint-on die spacer to accumulate in grooves of tooth preparation in sufficient thickness to exceed this accepted range of tolerance when applied using two different techniques. Eight die stone blocks with three grooves each were prepared. Half the samples were painted in unidirectional method and the other halves were painted using the haphazard method of application. The thickness of the die spacer was measured at different positions using 200× magnification and the mean and standard deviations were calculated. On analysis it was seen that the thickness of the paint-on die spacer in grooves was in the range of 20-40 ?m for unidirectional method of application, whereas in haphazard method of application the thickness of the paint-on die spacer was in the range of 28-132 ?m. From the above study it was concluded that the method of application influenced the thickness of the paint-on die spacer. The recommended thickness of the die spacer was achieved on unidirectional method of application. PMID:24431785

Vaishali, K; Prasad, D Krishna; Shetty, Manoj

2013-12-01

92

40 CFR 466.20 - Applicability; description of the cast iron basis material subcategory.  

Code of Federal Regulations, 2013 CFR

...Applicability; description of the cast iron basis material subcategory. 466.20 Section...ENAMELING POINT SOURCE CATEGORY Cast Iron Basis Material Subcategory § 466.20 Applicability; description of the cast iron basis material subcategory. This...

2013-07-01

93

40 CFR 466.20 - Applicability; description of the cast iron basis material subcategory.  

Code of Federal Regulations, 2014 CFR

...Applicability; description of the cast iron basis material subcategory. 466.20 Section...ENAMELING POINT SOURCE CATEGORY Cast Iron Basis Material Subcategory § 466.20 Applicability; description of the cast iron basis material subcategory. This...

2014-07-01

94

40 CFR 466.20 - Applicability; description of the cast iron basis material subcategory.  

Code of Federal Regulations, 2012 CFR

...Applicability; description of the cast iron basis material subcategory. 466.20 Section...ENAMELING POINT SOURCE CATEGORY Cast Iron Basis Material Subcategory § 466.20 Applicability; description of the cast iron basis material subcategory. This...

2012-07-01

95

40 CFR 466.20 - Applicability; description of the cast iron basis material subcategory.  

Code of Federal Regulations, 2011 CFR

...Applicability; description of the cast iron basis material subcategory. 466.20 Section...ENAMELING POINT SOURCE CATEGORY Cast Iron Basis Material Subcategory § 466.20 Applicability; description of the cast iron basis material subcategory. This...

2011-07-01

96

40 CFR 466.20 - Applicability; description of the cast iron basis material subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the cast iron basis material subcategory. 466.20 Section...ENAMELING POINT SOURCE CATEGORY Cast Iron Basis Material Subcategory § 466.20 Applicability; description of the cast iron basis material subcategory. This...

2010-07-01

97

40 CFR 464.30 - Applicability; description of the ferrous casting subcategory.  

Code of Federal Regulations, 2012 CFR

... Applicability; description of the ferrous casting subcategory. 464.30 Section 464.30...STANDARDS (CONTINUED) METAL MOLDING AND CASTING POINT SOURCE CATEGORY Ferrous Casting Subcategory § 464.30 Applicability;...

2012-07-01

98

40 CFR 464.30 - Applicability; description of the ferrous casting subcategory.  

Code of Federal Regulations, 2010 CFR

... Applicability; description of the ferrous casting subcategory. 464.30 Section 464.30...GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Ferrous Casting Subcategory § 464.30 Applicability;...

2010-07-01

99

40 CFR 464.30 - Applicability; description of the ferrous casting subcategory.  

Code of Federal Regulations, 2011 CFR

... Applicability; description of the ferrous casting subcategory. 464.30 Section 464.30...GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Ferrous Casting Subcategory § 464.30 Applicability;...

2011-07-01

100

40 CFR 464.30 - Applicability; description of the ferrous casting subcategory.  

Code of Federal Regulations, 2013 CFR

... Applicability; description of the ferrous casting subcategory. 464.30 Section 464.30...STANDARDS (CONTINUED) METAL MOLDING AND CASTING POINT SOURCE CATEGORY Ferrous Casting Subcategory § 464.30 Applicability;...

2013-07-01

101

40 CFR 464.30 - Applicability; description of the ferrous casting subcategory.  

Code of Federal Regulations, 2014 CFR

... Applicability; description of the ferrous casting subcategory. 464.30 Section 464.30...STANDARDS (CONTINUED) METAL MOLDING AND CASTING POINT SOURCE CATEGORY Ferrous Casting Subcategory § 464.30 Applicability;...

2014-07-01

102

Wear Behavior and Mechanism of a Cr-Mo-V Cast Hot-Working Die Steel  

NASA Astrophysics Data System (ADS)

The wear behavior and mechanisms of a Cr-Mo-V cast hot-working die steel with three microstructures (tempered martensite, troostite, and sorbite) were studied systematically through the dry-sliding wear tests within a normal load range of 50 to 300 N and an ambient temperature range of 298 K to 673 K (25 °C to 400 °C) by a pin-on-disk high-temperature wear machine. Five different mechanisms were observed in the experiments, namely adhesive, abrasive, mild oxidative, oxidative, and extrusive wear; one or more of those mechanisms would be dominant within particular ranges of load and temperature. The transition of wear mechanisms depended on the formation of tribo-oxides, which was related closely to load and temperature, and their delamination, which was mainly influenced by the matrix. By increasing the load and ambient temperature, the protective effect of tribo-oxides first strengthened, then decreased, and in some cases disappeared. Under a load ranging 50 to 300 N at 298 K (25 °C) and a load of 50 N at 473 K (200 °C), adhesive wear was the dominant wear mechanism, and abrasive wear appeared simultaneously. The wear was of mild oxidative type under a load ranging 100 to 300 N at 473 K (200 °C) and a load ranging 50 to 150 N at 673 K (400 °C) for tempered martensite and tempered troostite as well as under a load of 100 N at 473 K (200 °C) and a load ranging 50 to 100 N at 673 K (400 °C) for tempered sorbite. At the load of 200 N or greater, or the temperatures above 673 K (400 °C), oxidative wear (beyond mild oxidative wear) prevailed. When the highest load of 300 N at 673 K (400 °C) was applied, extrusive wear started to dominate for the tempered sorbite.

Wei, M. X.; Wang, S. Q.; Zhao, Y. T.; Chen, K. M.; Cui, X. H.

2011-06-01

103

Development of a 3D Filling Model of Low-Pressure Die-Cast Aluminum Alloy Wheels  

NASA Astrophysics Data System (ADS)

A two-phase computational fluid dynamics model of the low-pressure die-cast process for the production of A356 aluminum alloy wheels has been developed to predict the flow conditions during die filling. The filling model represents a 36-deg section of a production wheel, and was developed within the commercial finite-volume package, ANSYS CFX, assuming isothermal conditions. To fully understand the behavior of the free surface, a novel technique was developed to approximate the vent resistances as they impact on the development of a backpressure within the die cavity. The filling model was first validated against experimental data, and then was used to investigate the effects of venting conditions and pressure curves during die filling. It was found that vent resistance and vent location strongly affected die filling time, free surface topography, and air entrainment for a given pressure fill-curve. With regard to the pressure curve, the model revealed a strong relation between the pressure curve and the flow behavior in the hub, which is an area prone to defect formation.

Duan, Jianglan; Maijer, Daan; Cockcroft, Steve; Reilly, Carl

2013-12-01

104

Advanced Pattern Material for Investment Casting Applications  

SciTech Connect

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.

F. Douglas Neece Neil Chaudhry

2006-02-08

105

Fabrication of a Pb-Sn nanowire array gas sensor using a novel high vacuum die casting technique  

NASA Astrophysics Data System (ADS)

In this study, an anodic aluminum oxide nanomold was obtained by etching on an aluminum substrate at a purity of 99.7% with an oxalic acid electrolyte. After etching, a nanomold was prepared with pores that were measured at 80 nm in diameter. This nanomold was used as a base. Using the vacuum casting method, the Pb-Sn alloy was die-cast into the nanomold and consequently shaped into a Pb-Sn alloy nanowire of 80 nm in diameter and 50 µm in length. After solidification, a Pb-Sn nanowire array was obtained. The array of Pb-Sn nanowires prepared in this study can be applied to a gas sensor. Microstructural analysis of the AAO nanomold and the Pb-Sn nanowire array are performed by SEM and XRD.

Kuo, Chin-Guo; Chang, Ho; Hwang, Lih-Ren; Hor, Shu; Chen, Jia-Shin; Liu, Guo-yan; Cheng, Sheng-Cheng

2013-07-01

106

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

PubMed

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

Etchu, Y; Noguchi, H

1980-10-01

107

Thermal and metallographic characteristics of the Al–20% Si high-pressure die-casting alloy for monolithic cylinder blocks  

Microsoft Academic Search

Thermal analysis data were gathered to control the hypereutectic microstructure of the die-cast Al–20% Si cylinder block at a cooling rate of 1°C\\/s. The liquidus temperature was approximately 691±2.2°C, the nucleation temperature of the Al–Si eutectic was approximately 567.1±1.9°C and the nucleation temperature of the Cu- and Mg-enriched eutectic was approximately 513.6±1.4°C. The fraction solid increases linearly from 0 to

H. Yamagata; H. Kurita; M. Aniolek; W. Kasprzak; J. H. Sokolowski

2008-01-01

108

25 CFR 301.4 - Application of dies.  

Code of Federal Regulations, 2010 CFR

...301.4 Section 301.4 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER AND TURQUOISE PRODUCTS; STANDARDS § 301.4 Application of dies. Dies are to be applied to the object with the aid...

2010-04-01

109

25 CFR 301.4 - Application of dies.  

Code of Federal Regulations, 2011 CFR

...Section 301.4 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER AND TURQUOISE PRODUCTS; STANDARDS § 301.4 Application of dies. Dies are to be applied to the object with the aid of nothing...

2011-04-01

110

25 CFR 301.4 - Application of dies.  

Code of Federal Regulations, 2012 CFR

...Section 301.4 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER AND TURQUOISE PRODUCTS; STANDARDS § 301.4 Application of dies. Dies are to be applied to the object with the aid of nothing...

2012-04-01

111

25 CFR 301.4 - Application of dies.  

Code of Federal Regulations, 2013 CFR

...Section 301.4 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER AND TURQUOISE PRODUCTS; STANDARDS § 301.4 Application of dies. Dies are to be applied to the object with the aid of nothing...

2013-04-01

112

25 CFR 301.4 - Application of dies.  

Code of Federal Regulations, 2014 CFR

...Section 301.4 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER AND TURQUOISE PRODUCTS; STANDARDS § 301.4 Application of dies. Dies are to be applied to the object with the aid of nothing...

2014-04-01

113

An application of advanced control to steel casting  

Microsoft Academic Search

Accurate control of the ferro-static head in continuous casting is believed to be a key factor in improving the quality of the cast product. This paper describes an application of advanced control, that resulted in a complete re-commissioning of the investigated mould level control system. Careful physical modelling identified smooth as well as non-smooth nonlinearities in the process. The paper

S. F. Graebe; G. C. Goodwin; M. R. West; P. Stepien

1994-01-01

114

Thermal fatigue behavior of H-13 die steel for aluminum die casting with various ion sputtered coatings  

NASA Technical Reports Server (NTRS)

Sputtered coatings of Mo, W, Pt, Ag, Au, Co, Cr, Ni, Ag + Cu, Mo + Pt, Si3N4, A1N, Cr3C2, Ta5Si3, and ZrO2 were applied to a 2-inch-square, 7-inch-long thermal fatigue test specimen which was then internally water cooled and alternately immersed in molten aluminum and cooled in air. After 15,000 cycles the thermal fatigue cracks at the specimen corners were measured. Results indicate that a significant improvement in thermal fatigue resistance was obtained with platinum, molybdenum, and tungsten coatings. Metallographic examination indicates that the improvement in thermal fatigue resistance resulted from protection of the surface of the die steel from oxidation. The high yield strength and ductility of molybdenum and tungsten contributed to the better thermal fatigue resistance.

Nieh, C. Y.; Wallace, J. F.

1981-01-01

115

Microstructure and Mechanical Properties of Mg-7Al-2Sn Alloy Processed by Super Vacuum Die-Casting  

NASA Astrophysics Data System (ADS)

The microstructural evolution of Mg-7Al-2Sn (AT72) alloy processed by super vacuum die-casting and heat treated at various conditions was studied. The results showed that the dendritic microstructure in the as-cast AT72 alloy consisted of ?-Mg, Mg2Sn, and Mg17Al12 phases. After solution treatment at temperatures ranging from 663 K to 703 K (390 °C to 430 °C), the Mg17Al12 phase dissolved into the Mg matrix entirely, while the Mg2Sn phase partially dissolved into matrix. An average grain size of about 40 ?m in the alloy could be achieved after solution treatment at 683 K (410 °C) for 16 hours. A large amount of lath-shaped precipitates of Mg2Sn and Mg17Al12 was observed in the aged AT72 alloy. The results of tensile property evaluation at room temperature showed that the ductility of the solution-treated alloy was dramatically improved, in comparison with the as-cast alloy. In the peak aged condition, the tensile strength of the alloy was increased, which was attributed to the deposition of fine Mg17Al12 and Mg2Sn precipitates during the aging treatment.

Shi, Xiaoying; Li, Dejiang; Luo, Alan A.; Hu, Bin; Li, Li; Zeng, Xiaoqin; Ding, Wenjiang

2013-10-01

116

Process Modeling of Low-Pressure Die Casting of Aluminum Alloy Automotive Wheels  

NASA Astrophysics Data System (ADS)

Although on initial inspection, the aluminum alloy automotive wheel seems to be a relatively simple component to cast based on its shape, further insight reveals that this is not the case. Automotive wheels are in a select group of cast components that have strict specifications for both mechanical and aesthetic characteristics due to their important structural requirements and their visibility on a vehicle. The modern aluminum alloy automotive wheel continues to experience tightened tolerances relating to defects to improve mechanical performance and/or the physical appearance. Automotive aluminum alloy wheels are assessed against three main criteria: wheel cosmetics, mechanical performance, and air tightness. Failure to achieve the required standards in any one of these categories will lead to the wheel either requiring costly repair or being rejected and remelted. Manufacturers are becoming more reliant on computational process modeling as a design tool for the wheel casting process. This article discusses and details examples of the use of computational process modeling as a predictive tool to optimize the casting process from the standpoint of defect minimization with the emphasis on those defects that lead to failure of aluminum automotive wheels, namely, macroporosity, microporosity, and oxide films. The current state of applied computational process modeling and its limitations with regard to wheel casting are discussed.

Reilly, C.; Duan, J.; Yao, L.; Maijer, D. M.; Cockcroft, S. L.

2013-09-01

117

CAST  

NSDL National Science Digital Library

The Council for Agricultural Science and Technology (CAST) was formed in 1972 as a result of a meeting sponsored by the National Academy of Sciences' National Research Council. CAST's mission is to "assemble, interpret, and communicate credible science-based information regionally, nationally, and internationally to legislators, regulators, policymakers, the media, the private sector and the public." Visitors will find the Education tab near the top of the page to be particularly helpful for those who want to pursue agricultural careers or learn about agricultural education, such as 4-H or Future Farmers of America. The CAST Videos section has a number of PowerPoint presentations on current topics of importance in agriculture, such as "The Science and Regulation of Food from Genetically Engineered Animals," "Food Safety and Fresh Produce," and "Probiotics in Human Health." A number of the papers that accompany the PowerPoint presentations are available for free.

2012-02-03

118

Microstructure and corrosion behavior of die-cast AM60B magnesium alloys in a complex salt solution: A slow positron beam study  

SciTech Connect

The microstructure and corrosion behavior of high pressure die-cast (HPDC) and super vacuum die-cast (SVDC) AM60B magnesium alloys were investigated in a complex salt solution using slow positron beam technique and potentiodynamic polarization tests. The experiments revealed that a CaCO3 film was formed on the surface of the alloys and that the rate of CaCO3 formation for the SVDC alloy with immersion time was slower than that of the HPDC alloy. The larger volume fraction of b-phase in the skin layer of the SVDC alloy than that of the HPDC alloy was responsible for the better corrosion resistance.

Liu, Y.F. [Wuhan University] [Wuhan University; Qin, Q.L. [Wuhan University] [Wuhan University; Yang, W. [Wuhan University] [Wuhan University; Wen, W. [University of Kentucky] [University of Kentucky; Zhai, T. [University of Kentucky] [University of Kentucky; Yu, B. [University of Alberta] [University of Alberta; Liu, D.Y. [University of Alberta] [University of Alberta; Luo, A. [GM Research and Development Center] [GM Research and Development Center; Song, GuangLing [ORNL] [ORNL

2014-01-01

119

A partitioned resolution for concurrent fluid flow and stress analysis during solidification: application to ingot casting  

E-print Network

: application to ingot casting Michel Bellet, Okba Boughanmi, Grégory Fidel MINES ParisTech - CEMEF, CNRS UMR casting, or in the mould during continuous casting. The proposed approach consists of a partitioned two-step resolution strategy. 1. Introduction When modelling casting processes, one of the critical issue

Paris-Sud XI, Université de

120

Application of particle method to the casting process simulation  

NASA Astrophysics Data System (ADS)

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.

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

2012-07-01

121

Dry Sliding Wear Characteristics of Gravity Die-Cast Magnesium Alloys  

NASA Astrophysics Data System (ADS)

The paper deals with the wear behavior of conventional cast Mg-Sn-based alloys. The alloys were studied through pin- on- disk wear test under four different loading conditions; namely, 9.8, 19.6, 29.4, and 39.2 N. The study highlights the cumulative wear loss, volumetric wear loss, dry sliding wear rate, and coefficient of friction of the alloys. The volumetric wear increased with increasing applied load. The wear mechanism was studied with scanning electron microscope. The wear occurs mainly by plowing mechanism and also by delamination. During wear, extensive plastic deformation and work hardening occurred. Microstructural analysis has been carried out for all the alloys at different loading conditions.

Poddar, Palash; Das, Arpan; Sahoo, K. L.

2014-04-01

122

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

NASA Technical Reports Server (NTRS)

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.

Lee, Jonathan A.

2000-01-01

123

Predicting the Influence of Pore Characteristics on Ductility of Thin-Walled High Pressure Die Casting Magnesium  

SciTech Connect

In this paper, a two-dimensional microstructure-based finite element modeling method is adopted to investigate the effects of porosity in thin-walled high pressure die casting Mg materials on their ductility. For this purpose, the cross-sections of AM50 and AM60 casting samples are first examined using optical microscope to obtain the overall information on the pore characteristics. The experimentally quantified pore characteristics are then used to generate a series of synthetic microstructures with different pore sizes, pore volume fractions and pore size distributions. Pores are explicitly represented in the synthetic microstructures and meshed out for the subsequent finite element analysis. In the finite element analysis, an intrinsic critical strain value is used for the Mg matrix material, beyond which work-hardening is no longer permissible. With no artificial failure criterion prescribed, ductility levels are predicted for the various microstructures in the form of strain localization. Mesh size effect study is also conducted, from which a mesh size dependent critical strain curve is determined. A concept of scalability of pore size effects is then presented and examined with the use of the mesh size dependent critical strain curve. The results in this study show that, for the regions with lower pore size and lower volume fraction, the ductility generally decreases as the pore size and pore volume fraction increase whereas, for the regions with larger pore size and larger pore volume fraction, other factors such as the mean distance between the pores begin to have some substantial influence on the ductility. The results also indicate that the pore size effects may be scalable for the models with good-representative pore shape and distribution with the use of the mesh size dependent critical strain curve.

Sun, Xin; Choi, Kyoo Sil; Li, Dongsheng

2013-06-10

124

Strengthening Micromechanisms in Cold-Chamber High-Pressure Die-Cast Mg-Al Alloys  

NASA Astrophysics Data System (ADS)

The contributions from grain boundary, solid solution, and dispersion strengthening to the yield strength of cast-to-shape specimens were calculated for seven binary alloys with compositions ranging from very dilute (0.5 mass pct Al) to concentrated (12 mass pct Al). Experimentally and theoretically determined parameters were used to explicitly account for the different microstructures at the skin and core regions of specimens' cross sections. Microhardness maps were used to identify the specimens' skin. The specimens' strength was calculated as the weighted addition of the respective strengths of skin and core. The calculated strengths reproduced well the experimental values for the dilute alloys but underestimated the strength of the most concentrated alloys by as much as ~35 MPa. It is argued that the presence of the percolating network of Mg17Al12 eutectic intermetallic, particularly in the skin region, in conjunction with highly efficient dispersion hardening due to the convoluted shape of the intermetallics, accounts for the shortfall in the calculated strength.

Yang, Kun V.; Cáceres, Carlos H.; Easton, Mark A.

2014-08-01

125

Neurobehavioral testing of subjects exposed residentially to groundwater contaminated from an aluminum die-casting plant and local referents  

SciTech Connect

Residents adjoining a die-casting plant had excessive headaches, numbness of hands and feet, dizziness, blurred vision, staggering, sweating, abnormal heart rhythm, and depression, which led to measurements of neurobehavioral performance, affective status, and the frequency of symptoms. They had all been exposed via well water and proximity to the plant to volatile organic chemicals (VOC) and to polychlorinated biphenyls (PCBs). The 117 exposed women and men and 46 unexposed referents were studied together for simple and choice visual reaction time, body sway speed, blink reflex latency, color discrimination, Culture Fair (a nonverbal nonarithmetic intelligence test), recall of stories, figures, and numbers, cognitive and psychomotor control (slotted pegboard and trail making A and B), long-term memory, profile of mood states (POMS), and scores and frequencies of 34 symptoms. Choice reaction time, sway speed, and blink latency were impaired in both sexes of the exposed group and trail making B was impaired in exposed women. The POMS scores and frequencies of 30 of 34 symptoms were elevated in both sexes, compared to referents. Recall, long-term memory, psychomotor speed, and other cognitive function tests were reduced in exposed subjects and in the referents as compared to national referents. Neurophysiological impairment, and cognitive and psychomotor dysfunction and affective disorders, especially depression and excessive frequency of symptoms, were associated with the use of wells contaminated with VOCs, TCE and PCBs.

Kilburn, K.H.; Warshaw, R.H. (Univ. of California School of Medicine, Los Angeles (United States))

1993-08-01

126

Modeling and analysis of the effects of processing parameters on the performance characteristics in the high pressure die casting process of Al–SI alloys  

Microsoft Academic Search

The high pressure die casting (HPDC) process has achieved remarkable success in the manufacture of aluminum–silicon (Al–SI)\\u000a alloy components for the modern metal industry. Mathematical models are proposed for the modeling and analysis of the effects\\u000a of machining parameters on the performance characteristics in the HPDC process of Al–SI alloys which are developed using the\\u000a response surface methodology (RSM) to

Ko-Ta Chiang; Nun-Ming Liu; Te-Chang Tsai

2009-01-01

127

Effect of noise on human performance under variable load in a die casting industry--a case study.  

PubMed

The manual mode of working in industries is very common in the developing and under developed countries. Many industrial processes have generated high levels of noise and causing physiological effects on operators and thus leading to reduced performance. A survey was carried in various die casting industries to determine the levels of noise. It was found that the levels were in the range of 80-100dB(A). The survey also showed that the effects were more pronounced when the task was conducted under varying load conditions. Keeping this in view the problem was formulated to study whether the level of noise and amount of load has a bearing on human performance. For this purpose, experimental investigations in a simulated environment were carried out. Five subjects, all males and having no experience in the trade were selected for the task. The levels of noise under taken were 80, 90 and 100 dB(A) while the levels of load were 150, 200 and 250 N. A pulse oximeter was used to measure the human performance in terms of heart rate. The data was collected and analyzed on the basis of two factor repeated measure type of experimental design. Results of the study indicated that the level of noise and load both were having statistically significant effect on human performance. However, the interaction of level of noise and load was found to be statistically non-significant. The findings of the present work have been discussed in the light of the previous researches carried out on the topic. Suggestions have been made to reduce the levels of noise as per the recommendations of Occupational Safety and Health Association (1990). It is also suggested that instead of hand operated machines, foot operated versions should be used to reduce fatigue. PMID:16649592

Muzammil, M; Khan, Abid A; Hasan, F; Hasan, S N

2004-01-01

128

Energy and Technolgy Assessment of Zinc and Magnesium Casting Plants, Technical Report Close-out, August 25,2006  

SciTech Connect

Twin City Die Castings Company of Minneapolis, Minnesota, Twin City Die Castings Company was awarded project No. DE-FG36-05GO15097 to perform plant wide assessments of ten (10) die casting facilities that produce zinc and magnesium alloy castings in order to determine improvements and potential cost savings in energy use. Mr. Heider filled the role of team leader for the project and utilized the North American Die Casting Association (NADCA) to conduct audits at team participant plants so as to hold findings specific to each plant proprietary. The intended benefits of the project were to improve energy use through higher operational and process efficiency for the plants assessed. An improvement in energy efficiency of 5 – 15% was targeted. The primary objectives of the project was to: 1) Expand an energy and technology tool developed by the NADCA under a previous DOE project titled, “Energy and Technology Assessment for Die Casting Plants” for assessing aluminum die casting plants to be more specifically applicable to zinc and magnesium die casting facilities. 2) Conduct ten (10) assessments of zinc and magnesium die casting plants, within eight (8) companies, utilizing the assessment tool to identify, evaluate and recommend opportunities to enhance energy efficiency, minimize waste, and improve productivity. 3) Transfer the assessment tool to the die casting industry at large.

Twin City Die Castings Company; Tom Heider; North American Die Castings Association

2006-08-25

129

Improved life of die casting dies of H13 steel by attaining improved mechanical properties and distortion control during heat treatment. Year 1 report, October 1994--September 1995  

SciTech Connect

Optimum heat treatment of dies (quenching) is critical in ensuring satisfactory service performance: rapid cooling rates increase the thermal fatigue/heat checking resistance of the steel, although very fast cooling rates can also lead to distortion and lower fracture toughness, increasing the danger of catastrophic fracture. Goal of this project is to increase die life by using fast enough quenching rates (> 30 F/min ave cooling rate from 1750 to 550 F, 1/2 in. below working surfaces) to obtain good toughness and fatigue resistance in Premium grade H-13 steel dies. An iterative approach of computer modeling validated by experiment was taken. Cooling curves during gas quenching of H-13 blocks and die shapes were measured under 2, 5, and 7.5 bar N2 and 4 bar Ar. Resulting dimensional changes and residual stresses were determined. To facilitate the computer modeling work, a database of H-13 mechanical and physical properties was compiled. Finite element analysis of the heat treated shapes was conducted. Good fit of modeled vs measured quenched rates was demonstrated for simple die shapes. The models predict well the phase transformation products from the quench. There is good fit between predicted and measured distortion contours; however magnitude of predicted distortion and residual stresses does not match well the measured values. Further fine tuning of the model is required.

Wallace, J.F.; Schwam, D. [Case Western Reserve Univ., Cleveland, OH (United States)

1995-03-01

130

Clean Metal Casting  

SciTech Connect

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.

Makhlouf M. Makhlouf; Diran Apelian

2002-02-05

131

Casting materials and their application in research and teaching.  

PubMed

From a biological point of view, casting refers to filling of anatomical and/or pathological spaces with extraneous material that reproduces a three-dimensional replica of the space. Casting may be accompanied by additional procedures such as corrosion, in which the soft tissue is digested out, leaving a clean cast, or the material may be mixed with radiopaque substances to allow x-ray photography or micro computed topography (µCT) scanning. Alternatively, clearing of the surrounding soft tissue increases transparency and allows visualization of the casted cavities. Combination of casting with tissue fixation allows anatomical dissection and didactic surgical procedures on the tissue. Casting materials fall into three categories namely, aqueous substances (India ink, Prussian blue ink), pliable materials (gelatins, latex, and silicone rubber), or hard materials (methyl methacrylates, polyurethanes, polyesters, and epoxy resins). Casting has proved invaluable in both teaching and research and many phenomenal biological processes have been discovered through casting. The choice of a particular material depends inter alia on the targeted use and the intended subsequent investigative procedures, such as dissection, microscopy, or µCT. The casting material needs to be pliable where anatomical and surgical manipulations are intended, and capillary-passable for ultrastructural investigations. PMID:24564951

Haenssgen, Kati; Makanya, Andrew N; Djonov, Valentin

2014-04-01

132

Cooling slope casting and thixoforming of hypereutectic A390 alloy  

Microsoft Academic Search

A390 alloy offers outstanding wear resistance, high strength, low thermal expansion, excellent castability and low density and is thus the material of choice for heavy wear applications. Thixoforming of this alloy has received some attention recently since the conventional die casting route poses serious problems. In the present work, A390 alloy feedstock produced with cooling slope casting was thixoformed successfully

Yücel Birol

2008-01-01

133

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

SciTech Connect

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 deliver to industry a computer program in which all three systems are coupled for determining the dimensions of the wax pattern, the shell mold, and casting in a sequential but coupled manner.

Sabau, Adrian S [ORNL

2005-09-01

134

Improvement of drop shock and TC reliability for large die Wafer Level Packages in mobile application  

Microsoft Academic Search

In this study, board level drop shock and TC reliabilities in terms of solder materials and UBM (under bump metallurgy) structures have been evaluated to suggest optimal structures of WLP (wafer level packaging) with the large die, high pin counts for mobile application. Test vehicles of WLP have been designed with 5.6??5.6 mm die size, 340 um thickness (including backside

Jun-Kyu Lee; Yun-Mook Park; In-Soo Kang; Yong-Min Kwon; Kyung-Wook Paik

2009-01-01

135

38 CFR 11.128 - Veteran dies without having filed application for final settlement.  

Code of Federal Regulations, 2012 CFR

38 Pensions, Bonuses, and Veterans' Relief 1 2012-07-01 2012-07-01 false Veteran dies without having filed application for...Section 11.128 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS...

2012-07-01

136

38 CFR 11.128 - Veteran dies without having filed application for final settlement.  

Code of Federal Regulations, 2010 CFR

38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Veteran dies without having filed application for...Section 11.128 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS...

2010-07-01

137

Virtual aluminum castings: An industrial application of ICME  

Microsoft Academic Search

The automotive product design and manufacturing community is continually besieged by Hercule an engineering, timing, and cost\\u000a challenges. Nowhere is this more evident than in the development of designs and manufacturing processes for cast aluminum\\u000a engine blocks and cylinder heads. Increasing engine performance requirements coupled with stringent weight and packaging constraints\\u000a are pushing aluminum alloys to the limits of their

John Allison; Mei Li; C. Wolverton; Xuming Su

2006-01-01

138

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

NASA Technical Reports Server (NTRS)

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 mold of the calcium sulfate-bonded investment material. The shell mold is cooled to room temperature, and a ceramic slip is poured therein. After a ceramic shell of desired thickness has set up in the shell mold, excess ceramic slip is poured out. While still wet, the shell mold is peeled from the ceramic shell to expose any delicate or detailed parts, after which the ceramic shell is cured to provide a complete, detailed, precision ceramic article without parting lines.

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

1993-01-01

139

Commercialization of NASA's High Strength Cast Aluminum Alloy for High Temperature Applications  

NASA Technical Reports Server (NTRS)

In this paper, the commercialization of a new high strength cast aluminum alloy, invented by NASA-Marshall Space Flight Center, for high temperature applications will be presented. Originally developed to meet U.S. automotive legislation requiring low- exhaust emission, the novel NASA aluminum alloy offers dramatic improvement in tensile and fatigue strengths at elevated temperatures (450 F-750 F), which can lead to reducing part weight and cost as well as improving performance for automotive engine applications. It is an ideal low cost material for cast components such as pistons, cylinder heads, cylinder liners, connecting rods, turbo chargers, impellers, actuators, brake calipers and rotors. NASA alloy also offers greater wear resistance, dimensional stability, and lower thermal expansion compared to conventional aluminum alloys, and the new alloy can be produced economically from sand, permanent mold and investment casting. Since 2001, this technology was licensed to several companies for automotive and marine internal combustion engines applications.

Lee, Jonathan A.

2003-01-01

140

Application of SWAT and CAST model on Damma Glacier CZO  

NASA Astrophysics Data System (ADS)

Damma Glacier is one of the Critical Zone Observatories, located at the central Swiss Alps, Switzerland and is characterized by a 150-year soil chronosequence. In this study, we used the Soil and Water Assessment Tool (SWAT) to simulate the hydrology of the watershed of Damma glacier, Switzerland and of the extended area that feeds Goescheneralpsee and includes Damma watershed. SWAT was calibrated for the watershed of Damma glacier with the stream flow data collected between 2009 and 2011. Subsequently and in order to study the up-scalling effect, SWAT was run for the greater area using the same parameters. Carbon accumulation and aggregate formation along Damma soil chronosequence was modelled using ROTH-C and CAST models.

Andrianaki, Maria; Bernasconi, Stefano; Kobierska, Florian; Nikolaidis, Nikolaos

2014-05-01

141

The application of cast SiC/Al to rotary engine components  

NASA Technical Reports Server (NTRS)

A silicon carbide reinforced aluminum (SiC/Al) material fabricated by Dural Aluminum Composites Corporation was tested for various components of rotary engines. Properties investigated included hardness, high temperature strength, wear resistance, fatigue resistance, thermal conductivity, and expansion. SiC/Al appears to be a viable candidate for cast rotors, and may be applicable to other components, primarily housings.

Stoller, H. M.; Carluccio, J. R.; Norman, J. P.

1986-01-01

142

Feasibility Assessment for Pressure Casting of Ceramic-Aluminum Composites for NASA's Propulsion Applications  

NASA Technical Reports Server (NTRS)

Feasibility assessment of pressure casting of ceramic-aluminum composites for NASA% propulsion applications is summarized. A combination of several demonstration projects to produce three unique components for liquid hydrogen-oxygen rocket engine% flanges, valves and turbo-pump housing are conducted. These components are made from boron carbide, silicon carbide and alumina powders fabricated into complex net shaped parts using dry green powder compaction, slip casting or a novel 3D ink-jet printing process, followed by sintering to produce performs that can be pressure cast by infiltration with molten aluminum. I n addition, joining techniques are also explored to insure that these components can be assembled into a structure without degrading their highly tailored properties. The feasibility assessment was made to determine if these new materials could provide a significant weight savings, thereby reducing vehicle launch costs, while being durable materials to increase safety and performance for propulsion system.

Lee, Jonathan A.

2005-01-01

143

Cast Aluminum Alloys for High Temperature Applications Using Nanoparticles Al2O3 and Al3-X Compounds (X = Ti, V, Zr)  

NASA Technical Reports Server (NTRS)

In this paper, the effect of nanoparticles Al2O3 and Al3-X compounds (X = Ti, V, Zr) on the improvement of mechanical properties of aluminum alloys for elevated temperature applications is presented. These nanoparticles were selected based on their low cost, chemical stability and low diffusions rates in aluminum at high temperatures. The strengthening mechanism at high temperature for aluminum alloy is based on the mechanical blocking of dislocation movements by these nanoparticles. For Al2O3 nanoparticles, the test samples were prepared from special Al2O3 preforms, which were produced using ceramic injection molding process and then pressure infiltrated by molten aluminum. In another method, Al2O3 nanoparticles can also be homogeneously mixed with fine aluminum powder and consolidated into test samples through hot pressing and sintering. With the Al3-X nanoparticles, the test samples are produced as precipitates from in-situ reactions with molten aluminum using conventional permanent mold or die casting techniques. It is found that cast aluminum alloy using nanoparticles Al3-X is the most cost effective method to produce high strength aluminum alloys for high temperature applications in comparison to nanoparticles Al2O3. Furthermore, significant mechanical properties retention in high temperature environment could be achieved with Al3-X nanoparticles, resulting in tensile strength of nearly 3 times higher than most 300- series conventional cast aluminum alloys tested at 600 F.

Lee, Jonathan A.

2009-01-01

144

21 CFR 888.5980 - Manual cast application and removal instrument.  

Code of Federal Regulations, 2010 CFR

...nonpowered hand-held device intended to be used in applying or removing a cast. This generic type of device includes the cast knife, cast spreader, plaster saw, plaster dispenser, and casting stand. (b) Classification. Class I (general...

2010-04-01

145

A Partitioned Fluid-Structure Interaction Approach during Steel Solidification: Application to the simulation of Ingot Casting  

E-print Network

in the context of steel casting processes, is to achieve a concurrent and efficient computation of fluid flow separating the air to the injected material [6]. Furthermore, steel casting processes, du1 A Partitioned Fluid-Structure Interaction Approach during Steel Solidification: Application

Paris-Sud XI, Université de

146

Urinary casts  

MedlinePLUS

... Waxy casts; Casts in the urine; Fatty casts; Red blood cell casts; White blood cell casts ... by dehydration, exercise, or (water pills) diuretic medicines. Red blood cell casts are a sign of bleeding ...

147

The application of surface demoldability and moldability to side-core design in die and mold CAD  

Microsoft Academic Search

In casting, molding and forming processes, the surface geometries of the fabricated products are formed\\/molded by different functional components of tooling. In plastic injection molding, they are molded by core, cavity or side-cores. In die and mold CAD, how to identify the product surfaces formed\\/molded by the corresponding tool components for a given product CAD model is critical, as it

M. W. Fu

2008-01-01

148

Design and characterization of microscale heater structures for test die and sensor applications  

SciTech Connect

The authors describe a class of microscale heaters fabricated with CMOS processes on silicon wafers. These heaters were designed to produce localized high temperatures above 400 C for test and sensor applications. The temperature levels produced for various input powers and the thermal profiles surrounding the heater for packaged and wafer-level heater structures were studied to guide the placement of microelectronics integrated with the heater structures on the same die. To show the performance of the design, they present resistance sensor measurements, IR temperature profiles, and results from a 3D thermal model of the die. This effort demonstrates that it is possible to successfully operate both a microscale heater and microcircuits on the same die.

Benson, D.A.; Bowman, D.; Filter, W.; Mitchell, R. [Sandia National Labs., Albuquerque, NM (United States); Perry, J. [Philips Semiconductors, Albuquerque, NM (United States)

1998-05-01

149

40 CFR 420.60 - Applicability; description of the continuous casting subcategory.  

Code of Federal Regulations, 2012 CFR

...description of the continuous casting subcategory. 420...STANDARDS IRON AND STEEL MANUFACTURING POINT SOURCE CATEGORY Continuous Casting Subcategory § 420...resulting from the continous casting of molten steel into intermediate...

2012-07-01

150

40 CFR 420.60 - Applicability; description of the continuous casting subcategory.  

Code of Federal Regulations, 2013 CFR

...description of the continuous casting subcategory. 420...STANDARDS IRON AND STEEL MANUFACTURING POINT SOURCE CATEGORY Continuous Casting Subcategory § 420...resulting from the continous casting of molten steel into intermediate...

2013-07-01

151

40 CFR 420.60 - Applicability; description of the continuous casting subcategory.  

Code of Federal Regulations, 2014 CFR

...description of the continuous casting subcategory. 420...STANDARDS IRON AND STEEL MANUFACTURING POINT SOURCE CATEGORY Continuous Casting Subcategory § 420...resulting from the continous casting of molten steel into intermediate...

2014-07-01

152

Matched metal die compression molded structural random fiber sheet molding compound flywheel. [Patent application  

DOEpatents

A flywheel is described that is useful for energy storage in a hybrid vehicle automotive power system or in some stationary applications. The flywheel has a body of essentially planar isotropic high strength structural random fiber sheet molding compound (SMC-R). The flywheel may be economically produced by a matched metal die compression molding process. The flywheel makes energy intensive efficient use of a fiber/resin composite while having a shape designed by theory assuming planar isotropy.

Kulkarni, S.V.; Christensen, R.M.; Toland, R.H.

1980-09-24

153

Compaction die for forming a solid annulus on a right circular cylinder. [Patent application  

DOEpatents

A compacting die is disclosed wherein the improvement comprises providing a screen in the die cavity, the screen being positioned parallel to the side walls of said die and dividing the die cavity into center and annular compartments. In addition, the use of this die in a method for producing an annular clad ceramic fuel material is disclosed.

Harlow, J.L.

1981-09-14

154

75 FR 20387 - Contech Castings, LLC, Including Workers Whose Unemployment Insurance (UI) Wages Are Reported...  

Federal Register 2010, 2011, 2012, 2013, 2014

...to workers of Contech Castings, LLC, including on-site...production of aluminum and magnesium die casted component...new company, Contech Casting LLC was formed. Some...imports of aluminum and magnesium die casted component...All workers of Contech Castings, LLC, including...

2010-04-19

155

Cryogenic Fracture Toughness Evaluation of an Investment Cast Al-Be Alloy for Structural Applications  

NASA Technical Reports Server (NTRS)

Aluminum-Beryllium metal matrix composite materials are useful due to their desirable performance characteristics for aerospace applications. Desirable characteristics of this material includes light-weight, dimensional stability, stiffness, good vibration damping characteristics, low coefficient of thermal expansion, and workability, This material is 3.5 times stiffer and 22% lighter than conventional aluminum alloys. electro-optical systems, advanced sensor and guidance components for flight and satellite systems, components for light-weight high-performance aircraft engines, and structural components for helicopters. Aluminum-beryllium materials are now available in the form of near net shape investment castings. In this materials properties characterization study, the cryogenic tensile and fracture properties of an investment casting alloy, Beralcast 363, were determined. Tensile testing was performed at 21 C (70 F), -73.3 C (-100 F), -195.5 C (-320 F) and -252.8 C (-423 F), and fracture (K(sub lc) and da/dN) testing was performed at -73.3 C (-100 F), -195.5 C (-320 F) and -252.8 C (-423 F). Their use is attractive for weight critical structural applications such as advanced

Gamwell, W. R.; McGill, P. B.

2006-01-01

156

Effect of composition and processing on the thermal fatigue and toughness of high performance die steels. Year 1 report  

SciTech Connect

The goal of this project is to extend the lifetime of dies for die casting by 20%. Since the die contributes about 10% to the cost of die cast parts, such an improvement in lifetime would result in annual savings of over $200 Million dollars. This is based on the estimated annual die production of one Billion dollars in the US. The major tasks of this two year project are: (1) Evaluate NEW DIE STEEL COMPOSITIONS that have been developed for demanding applications and compare them to Premium Grade H-13 die steel. (2) Optimize the AUSTENITIZING TREATMENT of the new composition. Assess the effects of fast, medium and slow COOLING RATES DURING HEAT TREATMENT, on the thermal fatigue resistance and toughness of the die steel. (3) Determine the effect of ELECTRO-DISCHARGE MACHINING (EDM) on the thermal fatigue resistance and impact properties of the steel. (4) Select demanding components and conduct IN-PLANT TESTING by using the new steel. Compare the performance of the new steel with identical components made of Premium Grade H-13. The immersion thermal fatigue specimen developed at CWRU is being used to determine resistance to heat checking, and the Charpy V-notch test for evaluating the toughness. The overall result of this project will be identification of the best steel available on the market and the best processing methods for aluminum die casting dies. This is an interim report for year 1 of the project.

Wallace, J.F.; Wang, Yumin; Schwam, D.

1996-06-01

157

The application of X-ray stereo metrology to investment casting dimensional control  

SciTech Connect

High precision investment casting designs, particularly of jet engine and turbine components, are rapidly evolving in complexity. In order to reduce the development cycle for a new design it is necessary to monitor and control the critical dimensions of the casting and associated cores and molds. In addition, detailed knowledge of the casting geometry is necessary to plan, for example, the drilling of cooling holes during airfoil manufacturing. A new approach to dimensional control of casting manufacturing operations based on X-ray metrology will be described. Precise measurements of casting dimensions and hole geometry can be achieved by a combination of conventional X-ray CT algorithms and new algorithms for radiographic stereo. Together these provide both completeness of part description as well as high throughput for production monitoring. This paper will describe a system called the QUIC (QUality Investment Casting) system being developed to implement these algorithms.

Noble, J.A.; Mundy, J.L. [GE Corporate Research and Development Center, Schenectady, NY (United States)

1995-12-31

158

Laser assisted die bending: a new application of high power diode lasers  

NASA Astrophysics Data System (ADS)

Nowadays high power lasers are mainly used for cutting of sheet metals, for welding, hardening and rapid prototyping. In the forming of sheet metals as bending or deep drawing lasers are not used. Nevertheless a few years ago a new application of high power lasers has been invented, where bending of materials that break at room temperature becomes possible by heating them along the bending edge with high power lasers thus allowing their treatment without cracks and rupture. For this purpose a large number of diode lasers are arranged in the bottom tool of a bending machine (a V-shaped die) which heat up the initially flat sheet metal during the bending process what is performed by pressing it into the die with a knife shaped upper tool where due to the laser heating the material is softened and thus cracks are avoided. For the technical realization of the new process of laser assisted die bending, modules equipped with numerous laser diodes and a total beam power of 2,5 kW are used. The light emitted by these modules enters a tool with a length of 15cm and is deflected towards the workpiece. By using ten of these modules with adjacent dies and by integrating those in a bending press a bending edge of sheet metals with a length of 1500mm can be realized. Such a bending press with laser assistance also needs energization with a power of practically 50kW, a respective water flow, a heat exchanger system and also a control for all functions of this system. Special measures have also been developed to avoid radiating of those tools that are not covered by a workpiece in the case of bending edges shorter than the full length of the bending tools whereas individual short circuiting of diode modules can be performed. Specific measures to ensure a safe operation without any harm to the operational person have been realized. Exploitation of the bending process has been carried out for titanium, where material thicknesses up to 3mm have been bent successfully.

Schuöcker, D.; Schumi, T.; Spitzer, O.; Bammer, F.; Schuöcker, G.; Sperrer, G.

2015-02-01

159

Application of the fuzzy-based Taguchi method for the structural design of drawing dies  

Microsoft Academic Search

In the sheet metal stamping process for automobiles, the drawing process requires the greatest stamping force, and thus the\\u000a structure of the drawing dies is the thickest and heaviest among all stamping dies. This study describes how the fuzzy-based\\u000a Taguchi method can be applied to explore multi-objective optimization in the structural design of drawing dies. Using the\\u000a lower die of

Bor-Tsuen Lin; Chun-Chih Kuo

2011-01-01

160

Energy Saving Melting and Revert Reduction Technology (E-SMARRT): Mechanical Performance of Dies  

SciTech Connect

As a net shape process, die casting is intrinsically efficient and improvements in energy efficiency are strongly dependent on design and process improvements that reduce scrap rates so that more of the total consumed energy goes into acceptable, usable castings. A casting that is distorted and fails to meet specified dimensional requirements is typically remelted but this still results in a decrease in process yield, lost productivity, and increased energy consumption. This work focuses on developing, and expanding the use of, computer modeling methods that can be used to improve the dimensional accuracy of die castings and produce die designs and machine/die setups that reduce rejection rates due to dimensional issues. A major factor contributing to the dimensional inaccuracy of the casting is the elastic deformations of the die cavity caused by the thermo mechanical loads the dies are subjected to during normal operation. Although thermal and die cavity filling simulation are widely used in the industry, structural modeling of the die, particularly for managing part distortion, is not yet widely practiced. This may be due in part to the need to have a thorough understanding of the physical phenomenon involved in die distortion and the mathematical theory employed in the numerical models to efficiently model the die distortion phenomenon. Therefore, two of the goals of this work are to assist in efforts to expand the use of structural modeling and related technologies in the die casting industry by 1) providing a detailed modeling guideline and tutorial for those interested in developing the necessary skills and capability and 2) by developing simple meta�¢���models that capture the results and experience gained from several years of die distortion research and can be used to predict key distortion phenomena of relevance to a die caster with a minimum of background and without the need for simulations. These objectives were met. A detailed modeling tutorial was provided to NADCA for distribution to the industry. Power law based meta�¢���models for predicting machine tie bar loading and for predicting maximum parting surface separation were successfully developed and tested against simulation results for a wide range of machines and experimental data. The models proved to be remarkably accurate, certainly well within the requirements for practical application. In addition to making die structural modeling more accessible, the work advanced the state-of-the-art by developing improved modeling of cavity pressure effects, which is typically modeled as a hydrostatic boundary condition, and performing a systematic analysis of the influence of ejector die design variables on die deflection and parting plane separation. This cavity pressure modeling objective met with less than complete success due to the limits of current finite element based fluid�¢���structure�¢���interaction analysis methods, but an improved representation of the casting/die interface was accomplished using a combination of solid and shell elements in the finite element model. This approximation enabled good prediction of final part distortion verified with a comprehensive evaluation of the dimensions of test castings produced with a design experiment. An extra deliverable of the experimental work was development of high temperature mechanical properties for the A380 die casting alloy. The ejector side design objective was met and the results were incorporated into the metamodels described above. This new technology was predicted to result in an average energy savings of 2.03 trillion BTU�¢����s/year over a 10 year period. Current (2011) annual energy saving estimates over a ten year period, based on commercial introduction in 2009, a market penetration of 70% by 2014 is 4.26 trillion BTU�¢����s/year by 2019. Along with these en

R. Allen Miller, Principal Investigator; Contributors: Khalil Kabiri-Bamoradian; Abelardo Delgado-Garza; Karthik Murugesan; Adham Ragab

2011-09-13

161

Development of Functionally Graded Materials for Manufacturing Tools and Dies and Industrial Processing Equipment  

Microsoft Academic Search

Hot forming processes such as forging, die casting and glass forming require tooling that is subjected to high temperatures during the manufacturing of components. Current tooling is adversely affected by prolonged exposure at high temperatures. Initial studies were conducted to determine the root cause of tool failures in a number of applications. Results show that tool failures vary and depend

Louis Lherbier; David Novotnak; Herling; R. Darrell; James Sears

2009-01-01

162

The development of a nanostructured, graded multilayer Cr-CrxNy-Cr1-xAlxN coating produced by pulsed closed field unbalanced magnetron sputtering (P-CFUBMS) for use in aluminum pressure die casting dies.  

PubMed

The main objective of this research is to design an optimized 'coating system' that extends die life by minimizing premature die failure. The concept of the multilayer coating system with desired combinations of different kinds of single-layer coatings was introduced. A pulsed closed field unbalanced magnetron sputtering (P-CFUBMS) deposition system has been used to deposit Cr-CrxNy-Cr1-xAlxN compositionally graded multilayer coating structures. In this study, three power law scenarios have been adopted to vary the aluminum concentration in the graded Cr1-xAlxN layer: (i) p = 1, the aluminum concentration was increased linearly in the Cr1-xAlxN layer. (ii) p = 0.2, the Cr1-xAlxN layer is an aluminum-rich graded layer, and (iii) p = 2, the Cr1-xAlxN layer is a chromium-rich graded layer. It was found that all the graded coatings exhibit lower residual stress and higher adhesion strength than the homogeneous Cr1-xAlxN (x = 0.585) film. However, different power law grading architectures have significant influence on the hardness and wear resistance of the films. When p = 2 and p = 1, the graded films exhibited relatively low hardness values (24 and 26 GPa respectively) and high COF (0.55 to 0.60). When p = 0.2 the graded film exhibited both high hardness (34 GPa) and good wear resistance (COF = 0.45) due to the structural consistency in the graded zone. The paper discusses the correlation between the pulsing parameters and coating architecture with the resulting nanostructure and tribological properties of this Cr-CrxNy-Cr1-xAlxN coating system. PMID:19504877

Lin, Jianliang; Mishra, Brajendra; Myers, Sterling; Ried, Peter; Moore, John J

2009-06-01

163

Influence of Applied Pressure on Tensile Behaviour and Microstructure of Squeeze Cast Mg Alloy AM50 with Ca Addition  

Microsoft Academic Search

The development of alternative manufacturing processes is essential for the success in applying Ca-containing magnesium alloys\\u000a for automotive applications due to their relatively poor die castability. Squeeze casting with its inherent advantages has\\u000a been demonstrated capable of minimizing the formation of casting defects in Mg-Al-Ca alloys. In this study, the effect of\\u000a applied pressures on tensile behavior and microstructure of

Qiang Zhang; Mohsen Masoumi; Henry Hu

2011-01-01

164

Development of a Small Die-Small Form Factor Flip Chip Package for Application in LAN Products  

Microsoft Academic Search

LAN products using Flip Chip interconnect necessitated the development of a new packaging technology involving very small die sizes and package form factors. This paper describes the development of the package assembly technology, the challenges associated with it, the thermalmechanical aspects of the package, application to a Dual Port Gigabit Ethernet Controller (on 90 nm Si process), and finally the

Altaf Hasan; Glenn Robertson; Kofi Mensah; A. Molina

2005-01-01

165

Ceramic membrane by tape casting and sol-gel coating for microfiltration and ultrafiltration application  

NASA Astrophysics Data System (ADS)

Alumina membrane filters in the form of thin (0.3-0.8 mm) discs of 25-30 mm diameter suitable for microfiltration application have been fabricated by tape-casting technique. Further using this microfiltration membrane as substrate, boehmite sol coating was applied on it and ultrafiltration membrane with very small thickness was formed. The pore size of the microfiltration membrane could be varied in the range of 0.1-0.7 ?m through optimisation of experimental parameter. In addition, each membrane shows a very narrow pore size distribution. The most important factor, which determines the pore size of the membrane, is the initial particle size and its distribution of the ceramic powder. The top thin ultrafiltration, boehmite layer was prepared by sol-gel method, with a thickness of 0.5 ?m. Particle size of the sol was approximately 30-40 nm. The structure and formation of the layer was analysed through TEM. At 550 °C formation of the top layer was completed. The pore size of the ultrafiltration membrane measured from TEM micrograph was almost 10 nm. Results of microbial (Escherichia coli—smallest-sized water-borne bacteria) test confirm the possibility of separation through this membrane

Das, Nandini; Maiti, H. S.

2009-11-01

166

Evaluation and Application of Alternative Die Materials Using Simulation technology for the High Pressure Diecasting industry  

Microsoft Academic Search

Alternative die materials have been routinely used in the high pressure diecasting industry to take advantage of the material's thermophysical properties. Notable among these is an alloy made from refractory material, which contains 80% tungsten. Typically, the choice for an alternative to H13 die material is considered only when all ingenious avenues to solve porosity problems in relatively thick sections

Winston Sequeira; Matt Proske; Dave Fitzgerald; Dave Bandy

167

[Determination of titanium flow by the tracer element molten method in the dental precision casting. 1. The principle of flow visualization and application to simple castings].  

PubMed

The tracer element molten (TEM) method has been developed for flow visualization of molten Titanium in dental precision casting. The principle of this technique is as follows. When Titanium is cast, the tracer element wire inserted previously into the selective point of the sprue is molten little by little and distributed according to the molten Titanium flow in the mold cavity. After solidification, to observe the flow pattern, the tracer element needs to be analyzed on a section of the casting by EPMA equipped with the stage scan mapping system. This technique using Ag, Au, Pd or Pt as a tracer has been applied to some simple castings in shape and has been confirmed to be a very powerful technique for Titanium flow visualization in dental castings. PMID:2134828

Watanabe, K; Okawa, S; Miyakawa, O; Nakano, S; Shiokawa, N; Kobayashi, M

1990-07-01

168

[Variables effecting casting accuracy of quick heating casting investments].  

PubMed

Recently, several new products of investments for "quick heating" have been put on the Japanese market. The total casting procedure time for this quick heating method involves only one hour; 30-minutes waiting after the start of mixing before placing the mold directly into the 700 degrees C furnace and 30-minutes heating in the furnace. The purpose of this study was to evaluate two variables effecting casting accuracy using these new investments. The effect of thickness of the casting liner inside the casting ring and the effect of waiting time before placing the mold into the 700 degrees C furnace were evaluated. A stainless-steel die with a convergence angle of 8 degrees was employed. Marginal discrepancies of the crown between the wax patterns and castings were measured. The size of the cast crown became larger when the thickness of the ring liner was thick and when the waiting time before placing the mold into the furnace was long. These results suggest that these new investments have the advantage of providing sound castings using short-time casting procedures. However, it is necessary to pay careful attention to the casting conditions for obtaining reproducible castings. PMID:7930818

Takahashi, H; Nakamura, H; Iwasaki, N; Morita, N; Habu, N; Nishimura, F

1994-06-01

169

Rapid casting solutions: a review  

Microsoft Academic Search

Purpose – This paper seeks to review the industrial applications of state-of-the-art additive manufacturing (AM) techniques in metal casting technology. An extensive survey of concepts, techniques, approaches and suitability of various commercialised rapid casting (RC) solutions with traditional casting methods is presented. Design\\/methodology\\/approach – The tooling required for producing metal casting such as fabrication of patterns, cores and moulds with

Munish Chhabra; Rupinder Singh

2011-01-01

170

Applications of Virtual Reality in Design and Simulation of Holonic Manufacturing Systems: A Demonstration in Die-Casting Industry  

Microsoft Academic Search

This paper presents the concepts and the techniques of implementation of Virtual Reality (VR) - based simulations into the\\u000a design of the Holonic Manufacturing Systems. An integrated methodology is presented, which has been developed for modelling\\u000a and simulations of a manufacturing system with holonic control with the aid of VR. The main focus is given to the implementation\\u000a in small

Mert Bal; Majid Hashemipour

2007-01-01

171

Standard digital reference images for investment steel castings for aerospace applications  

E-print Network

1.1 The digital reference images provided in the adjunct to this standard illustrate various types and degrees of discontinuities occurring in thin-wall steel investment castings. Use of this standard for the specification or grading of castings requires procurement of the adjunct digital reference images which illustrate the discontinuity types and severity levels. They are intended to provide the following: 1.1.1 A guide enabling recognition of thin-wall steel casting discontinuities and their differentiation both as to type and degree through digital radiographic examination. 1.1.2 Example digital radiographic illustrations of discontinuities and a nomenclature for reference in acceptance standards, specifications and drawings. 1.2 Two illustration categories are covered as follows: 1.2.1 Graded—Six common discontinuity types each illustrated in eight degrees of progressively increasing severity. 1.2.2 Ungraded—Twelve single illustrations of additional discontinuity types and of patterns and imper...

American Society for Testing and Materials. Philadelphia

2010-01-01

172

Application of the Billet Casting Method to Determine the Onset of Incipient Melting of 319 Al Alloy Engine Blocks  

NASA Astrophysics Data System (ADS)

The increased use of Al for automotive applications has resulted from the need to improve vehicle fuel efficiency. Aluminum alloy engine blocks fulfil the need of lightweighting. However, there are many challenges associated with thermo-mechanical mismatch between Al and the gray cast iron cylinder liners, which result in large tensile residual stress along the cylinder bores. This requires improced mechanical properties in this region to prevent premature engine failure. In this study, replicating billet castings were used to simulate the engine block solution heat treatment process and determine the onset of incipient melting. Microstructural changes during heat treatment were assessed with SEM and EDX, while thermal analysis was carried out using differential scanning calorimetry. The results suggest that solution heat treatment at 500 °C was effective in dissolving secondary phase particles, while solutionizing at 515 or 530 °C caused incipient melting of Al2Cu and Al5Mg8Cu2Si6. Incipient melting caused the formation ultra-fine eutectic clusters consisting of Al, Al2Cu, and Al5Mg8Cu2Si6 on quenching. In addition, DSC analysis found that incipient melting initiated at 507 °C for all billets, although the quantity of local melting reduced with microstructural refinement as evidenced by smaller endothermic peaks and energy absorption. The results from this study will assist in improving engine block casting integrity and process efficiency.

Lombardi, A.; Ravindran, C.; MacKay, R.

2015-02-01

173

MPS-C2 and Post Encapsulation Grinding technology for ultra fine pitch and thin die flip chip applications  

Microsoft Academic Search

Flip chip technology is now being introduced in PoP(Package on Package) packages for the digital consumer electronics such as digital still cameras and mobile phones. PoP reduces the component height and improves the electrical performance. A MPS-C2(Metal Post Solder Chip Connection) method was developed for ultrafine pitch flip chip interconnections in mobile applications. A bare die with Sn\\/Ag-solder-capped Cu post

Yasumitsu Orii; Kazushige Toriyama; Yukifumi Oyama; Toshihiko Nishio

2008-01-01

174

Comparison of accuracy of multiunit one-piece castings.  

PubMed

An investigation was conducted to evaluate the accuracy of one-piece castings of FPDs consisting of three, four, and five units with a ceramometal alloy cast in a large circular ring. A three-piece aluminum mold with stainless steel dies simulating the various lengths of the FPDs was used. A total of 18 castings, six castings for each FPD, were fabricated. Marginal discrepancies of the castings on the dies and the length of the castings were compared before and after sectioning the castings at the connectors. The following conclusions were drawn from the study. Seating of the castings improved approximately 50% after sectioning, which indicates that the castings were distorted. The distortion was a three-dimensional phenomenon, with the greatest discrepancy on the mesiogingival surface of the anterior retainer and on the distolingual surface of the posterior retainer. The distortion was least for the three-unit FPDs and greatest for the five-unit FPDs. The lingual-facial diameter of the castings at the gingival axial line angle was significantly larger than the dies in most cases. The mesiodistal diameter of the castings at the gingival axial line angle was smaller than that of the dies but was only significant with the three-unit FPDs. Although the castings were slightly oversized or undersized, the primary reason the castings did not seat was warpage. PMID:3908654

Schiffleger, B E; Ziebert, G J; Dhuru, V B; Brantley, W A; Sigaroudi, K

1985-12-01

175

Overview of the ToxCast Research Program: Applications to Predictive Toxicology and Chemical Prioritization  

EPA Science Inventory

EPA?s ToxCast program, the NTP?s HTS initiative, and the NCGC?s Molecular Libraries Initiative into a collaborative research program focused on identifying toxicity pathways and developing in vitro assays to characterize the ability of chemicals to perturb those pathways. The go...

176

The Second Phase of ToxCast and Initial Applications to Chemical Prioritization  

EPA Science Inventory

Tens of thousands of chemicals and other contaminants exist in our environment, but only a fraction of these have been characterized for their potential hazard to humans. ToxCast is focused on closing this data gap and improving the management of chemical risk through a high thro...

177

Application of process modeling to improve the competitiveness of investment castings  

NASA Astrophysics Data System (ADS)

The aerospace and automotive industries are the largest users of computer-aided design, engineering, and manufacturing (CAD/CAM) systems for designing and manufacturing component parts. Many producers of metal castings are adopting the technology to strengthen business relationships with their aerospace and automotive OEM customers by reducing new product development times, improving yields of existing processes, and reducing costs. One key limitation of the technology is that the accuracies of even the basic heat and fluid flow models must be enhanced by improving the input property databases for the many commercial casting alloys of interest. Accurate models require accurate input thermophysical and related property data such as thermal conductivity, specific heat, latent heat, density, surface tension, emissivity, viscosity, and contact conductance between the metal and the mold. This paper describes the economic impacts of the casting industry and how CAD/CAE/CAM technology is revolutionizing business practices in foundries. A specific example of an CAE model of a production investment casting will be presented. In addition, the commercial potential of low-g measurements of key thermophysical properties will be discussed.

Overfelt, Tony; Tu, John; Aimone, Paul; Mueller, Boyd

1996-03-01

178

Overview of the ToxCast Research Program: Applications to Predictive Toxicology and Chemical Prioritization (SETAC)  

EPA Science Inventory

Understanding the potential health risks posed by environmental chemicals is a significant challenge driven by the large number of diverse chemicals with generally uncharacterized exposures, mechanisms and toxicities. The U.S. EPA?s ToxCast chemical prioritization research projec...

179

van die Universiteit Stellenbosch Die kern van die beleid  

E-print Network

as akademiese taal, maar neem daarmee saam die multikulturele en meertalige #12;2 Suid-Afrikaanse werklikheid- prosesse. 4. Die Taalbeleid neem die waardes en uitgangspunte wat in die Strategiese Raamwerk van die daarvan. 8. Die Taalbeleid neem die diversiteitsdoelwitte van die Universiteit in ag. 9. Die Taalbeleid

Geldenhuys, Jaco

180

Optimization of Composition and Heat Treating of Die Steels for Extended Lifetime  

SciTech Connect

An ''average'' die casting die costs fifty thousand dollars. A die used in making die cast aluminum engine blocks can cost well over one million dollars. These costs provide a strong incentive for extension of die life. While vacuum quenched Premium Grade H13 dies have become the most widely used in the United States, tool makers and die casters are constantly searching for new steels and heat treating procedures to extend die life. This project was undertaken to investigate the effects of composition and heat treating on die life and optimize these parameters.

David Schwam; John F. Wallace; Quanyou Zhou

2002-01-30

181

PREFACE: International Conference on Advancement in Science and Technology 2012 (iCAST): Contemporary Mathematics, Mathematical Physics and their Applications  

NASA Astrophysics Data System (ADS)

The 4th International Conference on the Advancement of Science and Technology 2012 (iCAST 2012), with theme 'Contemporary Mathematics, Mathematical Physics and their Applications', took place in Kuantan, Malaysia, from Wednesday 7 to Friday 9 November 2012. The conference was attended by more than 100 participants, and hosted about 160 oral and poster papers by more than 140 pre-registered authors. The key topics of the 4th iCAST 2012 include Pure Mathematics, Applied Mathematics, Theoretical/Mathematical Physics, Dynamical Systems, Statistics and Financial Mathematics. The scientific program was rather full since after the Keynote and Invited Talks in the morning, four parallel sessions ran every day. However, according to all attendees, the program was excellent with a high level of talks and the scientific environment was fruitful; thus all attendees had a creative time. The conference aimed to promote the knowledge and development of high-quality research in mathematical fields concerned with the application of other scientific fields as well as modern technological trends in physics, chemistry, biology, medicine, economics, sociology and environmental sciences. We would like to thank the Keynote and the Invited Speakers for their significant contributions to 4th iCAST 2012. We would also like to thank the members of the International Scientific Committee and the members of the Organizing Committee. We cannot end without expressing our many thanks to International Islamic University Malaysia and our sponsors for their financial support . This volume presents selected papers which have been peer-reviewed. The editors hope that it may be useful and fruitful for scholars, researchers, and advanced technical members of the industrial laboratory facilities for developing new tools and products. Guest Editors Nasir Ganikhodjaev, Farrukh Mukhamedov and Pah Chin Hee The PDF contains the committee lists, board list and biographies of the plenary speakers.

Ganikhodjaev, Nasir; Mukhamedov, Farrukh; Hee, Pah Chin

2013-04-01

182

Flaw evaluation of theramally aged cast stainless steel in light-water reactor applications  

Microsoft Academic Search

Cast stainless steel may be used in the fabrication of the primary loop piping, fittings, valve bodies, and pump casings in light-water reactors. However, this material is subject to embrittlement due to thermal aging at the reactor temperature, that is, 290°C (550°F). The Argonne National Laboratory (ANL) recently completed a research program and the results indicate that the lower-bound fracture

O. Chopra

1997-01-01

183

Processing of Advanced Cast Alloys for A-USC Steam Turbine Applications  

NASA Astrophysics Data System (ADS)

The high-temperature components within conventional supercritical coal-fired power plants are manufactured from ferritic/martensitic steels. To reduce greenhouse-gas emissions, the efficiency of pulverized coal steam power plants must be increased to as high a temperature and pressure as feasible. The proposed steam temperature in the DOE/NETL Advanced Ultra Supercritical power plant is high enough (760°C) that ferritic/martensitic steels will not work for the majority of high-temperature components in the turbine or for pipes and tubes in the boiler due to temperature limitations of this class of materials. Thus, Ni-based superalloys are being considered for many of these components. Off-the-shelf forged nickel alloys have shown good promise at these temperatures, but further improvements can be made through experimentation within the nominal chemistry range as well as through thermomechanical processing and subsequent heat treatment. However, cast nickel-based superalloys, which possess high strength, creep resistance, and weldability, are typically not available, particularly those with good ductility and toughness that are weldable in thick sections. To address those issues related to thick casting for turbine casings, for example, cast analogs of selected wrought nickel-based superalloys such as alloy 263, Haynes 282, and Nimonic 105 have been produced. Alloy design criteria, melt processing experiences, and heat treatment are discussed with respect to the as-processed and heat-treated microstructures and selected mechanical properties. The discussion concludes with the prospects for full-scale development of a thick section casting for a steam turbine valve chest or rotor casing.

Jablonski, Paul D.; Hawk, Jeffery A.; Cowen, Christopher J.; Maziasz, Philip J.

2012-02-01

184

Low Frequency Phased Array Application for Crack Detection in Cast Austenitic Piping  

SciTech Connect

As part of a multi-year program funded by the United States Nuclear Regulatory Commission (US NRC) to address nondestructive examination (NDE) reliability of inservice inspection (ISI) programs, studies conducted at the Pacific N¬orthwest National Laboratory (PNNL) in Richland, Washington, have focused on assessing novel NDE approaches for the inspection of coarse-grained, cast stainless steel reactor components. The primary objective of this work is to provide information to the US NRC on the utility, effec¬tiveness and reliability of ultrasonic testing (UT) as related to the ISI of primary piping components in US commercial nuclear power plants. This paper describes progress, recent developments and results from an assessment of a portion of the work relating to the ultrasonic low frequency phased array inspection technique. Westinghouse Owner’s Group (WOG) cast stainless steel pipe segments with thermal and mechanical fatigue cracks, PNNL samples containing thermal fatigue cracks and several blank vintage specimens having very coarse grains that are representative of early centrifugally cast piping installed in PWRs, were used for assessing the inspection method. The phased array approach was implemented using an R/D Tech Tomoscan III system operating at 1.0 MHz and 500 kHz, providing composite volumetric images of the samples. Several dual, transmit-receive, custom designed low-frequency arrays were employed in laboratory trials. Results from laboratory studies for assessing detection, localization and length sizing effectiveness are discussed.

Anderson, Michael T.; Cumblidge, Stephen E.; Doctor, Steven R.

2006-10-01

185

High-Strength Aluminum Casting Alloy for High-Temperature Applications (MSFC Center Director's Discretionary Fund Final Project No. 97-10)  

NASA Technical Reports Server (NTRS)

A new aluminum-silicon alloy has been successfully developed at Marshall Space Flight Center that has a significant improvement in tensile strength at elevated temperatures (550 to 700 F). For instance, the new alloy shows in average tensile strength of at least 90 percent higher than the current 390 aluminum piston alloy tested at 500 F. Compared to conventional aluminum alloys, automotive engines using the new piston alloy will have improved gas mileage, and may produce less air pollution in order to meet the future U.S. automotive legislative requirements for low hydrocarbon emissions. The projected cost for this alloy is less than $0.95/lb, and it readily allows the automotive components to be cast at a high production volume with a low, fully accounted cost. It is economically produced by pouring molten metal directly into conventional permanent steel molds or die casting.

Lee, J. A.

1998-01-01

186

Marginal discrepancy as affected by selective placement of die-spacer: an in vitro study.  

PubMed

An increase in the marginal discrepancy is seen after cementation with a luting agent and provision of cement space with a die-spacer is the most preferred method to avoid it. Recommended thickness of die-spacer is 25-40 ?m. Smaller die-spacer thickness was consistently found at the axio-occlusal line angles as compared to the other surfaces which has been postulated to that the spacer paint tends to flow away from the sharp line angles and cusp tips as a result of increased surface tension. The absence of adequate relief spaces in these areas impedes the flow of cement beyond the occlusal portion of the casting, which would result in incomplete seating because of hydraulic pressure. Fifty stone dies were duplicated from a steel die and were divided into five groups of sample size 10, where the die-spacer was selectively placed. Measurements were taken at four points, 90° apart from each other with the help of optical microscope. Later all the castings were cemented using Glass Inomer cement as a luting agent, under a 10 kg static load and measurements were recorded. Statistical analysis showed samples with no spacer had the maximum pre and post cementation gap while the least discrepancy was seen in group with additional layer of die-spacer painted over the axio-occlusal line angle. The results were highly significant which clearly indicated the superiority of this group over others. Within limitations of the study, it can be said that application of additional layer of die-spacer at the axio-occlusal line angle will help in decreasing the post cementation marginal discrepancy in full cast metal crowns. PMID:23997463

Aditya, Priyam; Madhav, V N V; Bhide, S V; Aditya, Amita

2012-09-01

187

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

SciTech Connect

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.

Y. A. Owusu

1999-03-31

188

Application of an integrated CAD\\/CAE\\/CAM system for stamping dies for automobiles  

Microsoft Academic Search

The globalization and competition in the automobile industry makes it necessary to reduce the time spent on product development.\\u000a Therefore, computer aided product development has become one of the most important techniques in the automobile industry.\\u000a According to the concurrent engineering concept, an integrated CAD\\/CAE\\/CAM system for automobile stamping die development\\u000a is established. The system is based on 3D surface

Bor-Tsuen Lin; Chun-Chih Kuo

2008-01-01

189

Design, development, and qualification of special super N-channel MOSFET die for space applications  

NASA Astrophysics Data System (ADS)

The design, manufacture, processing and testing of special super Metal Oxide Semiconductor Field Effect Transistors (MOSFET) die sizers 9 and 10 (approx. 690 by 500 mils and 1022 by 772 mils respectively) are described. These sizes are developed specifically to meet the requirements of the Remote Power Controller (RPC), the Remote Bus Isolator (RBI) and the DC to DC converter of the Space Station Freedom power management and distribution system. The reliability goal is for a 15 year failure free operation in space.

Joseph, Haskel M.

1991-03-01

190

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

SciTech Connect

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 the shell mold. A model for thermal radiation within the shell mold was developed, and the thermal model was successfully validated using ProCAST. 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 prefiring of the empty shell mold was considered in the model, and the shell mold was limited to a pure elastic material. The alloy dimensions were obtained from numerical simulations only with coupled shell-alloy systems. The alloy dimensions were in excellent quantitative agreement with experimental data, validating the deformation module. For actual parts, however, the creep properties of the shell molds must also be obtained, modeled, and validated.

Nick Cannell (EMTEC); Adrian S. Sabau (ORNL)

2005-09-30

191

Fit of porcelain fused-to-metal crown and bridge castings.  

PubMed

The dimensional accuracy of porcelain fused to metal crown and bridge castings was determined on truncated cone-shaped steel dies. Ni-Cr castings produced in manufacturers' laboratories were consistently undersize, while precious metal castings were consistently oversize. Ni-Cr castings, produced in NBS laboratories using a modified investing technique, were routinely oversize. PMID:389980

Eden, G T; Franklin, O M; Powell, J M; Ohta, Y; Dickson, G

1979-12-01

192

Melting and casting of FeAl-based cast alloy  

SciTech Connect

The FeAl-based intermetallic alloys are of great interest because of their low density, low raw material cost, and excellent resistance to high-temperature oxidation, sulfidation, carburization, and molten salts. The applications based on these unique properties of FeAl require methods to melt and cast these alloys into complex-shaped castings and centrifugal cast tubes. This paper addresses the melting-related issues and the effect of chemistry on the microstructure and hardness of castings. It is concluded that the use of the Exo-Melt{trademark} process for melting and the proper selection of the aluminum melt stock can result in porosity-free castings. The FeAl alloys can be melted and cast from the virgin and revert stock. A large variation in carbon content of the alloys is possible before the precipitation of graphite flakes occurs. Titanium is a very potent addition to refine the grain size of castings. A range of complex sand castings and two different sizes of centrifugal cast tubes of the alloy have already been cast.

Sikka, V.K. [Oak Ridge National Lab., TN (United States); Wilkening, D. [Columbia Falls Aluminum Co., Columbia Falls, MT (United States); Liebetrau, J.; Mackey, B. [AFFCO, L.L.C., Anaconda, MT (United States)

1998-11-01

193

High density tape casting system  

NASA Technical Reports Server (NTRS)

A system is provided for casting thin sheets (or tapes) of particles bound together, that are used for oxygen membranes and other applications, which enables the particles to be cast at a high packing density in a tape of uniform thickness. A slurry contains the particles, a binder, and a solvent, and is cast against the inside walls of a rotating chamber. Prior to spraying the slurry against the chamber walls, a solvent is applied to a container. The solvent evaporates to saturate the chamber with solvent vapor. Only then is the slurry cast. As a result, the slurry remains fluid long enough to spread evenly over the casting surface formed by the chamber, and for the slurry particles to become densely packed. Only then is the chamber vented to remove solvent, so the slurry can dry. The major novel feature is applying solvent vapor to a rotating chamber before casting slurry against the chamber walls.

Collins, Earl R., Jr. (inventor)

1989-01-01

194

Neutron radiography inspection of investment castings  

Microsoft Academic Search

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 1in (2.54cm). Recently, airframe manufacturers have been exploring the use of titanium investment casting to replace components traditionally produced from

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

2004-01-01

195

Fabrication of 3Y-TZP\\/SUS304 functionally graded materials by slip casting; application of porous alumina molds  

Microsoft Academic Search

Three mole percent Y2O3 doped tetragonal zirconia polycrystals (TZP) and stainless steel 304 (SUS) functionally graded materials (FGM) were fabricated by slip casting. To overcome the problems of the gypsum mold (GM) in the slip casting process, an alumina mold (AM) was prepared and its properties investigated after controlling the microstructure and the sintering conditions. The optimal conditions for the

Yeon-Gil Jung; Sung-Churl Choi

1998-01-01

196

Die Primzahlen  

Microsoft Academic Search

Ihren mystischen Nimbus haben die natürlichen Zahlen nach und nach verloren; aber niemals ist das Interesse von Mathematikern\\u000a und Laien an den Gesetzen der Zahlenwelt schwächer geworden. Es mag sein, daß Euklids Ruhm auf der geometrischen Deduktion seiner „Elemente“ beruht; bis heute haben die „Elemente“ jedenfalls den Unterricht\\u000a in der Geometrie entscheidend beeinflußt. Und doch war Euklids Geometrie im wesentlichen

Richard Courant; Herbert Robbins

197

Numerical simulation of macrostructure formation in centrifugal casting of particle reinforced metal matrix composites. Part 2: simulations and practical applications  

NASA Astrophysics Data System (ADS)

Centrifugal casting is a widely applied method for production of graded metal matrix composites (MMCs). This paper discusses some aspects of the macrostructure management of centrifugally cast particle reinforced MMCs. A specially developed software product is applied for the analysis of many technological regimes for casting cylindrical sleeves of composite alloy A356 and SiC particles as reinforcing phase. A number of technological recommendations are made. Castings of aluminium alloy A356 and copper alloy C90300 with Ni coated graphite particles of diameter 100 mum introduced as reinforcing phase are discussed. Some typical and unusual casting structures are analysed using the specially developed software product. This software is based on the mathematical model described in detail in part 1.

Drenchev, Ludmil; Sobczak, Jerzy; Malinov, Savko; Sha, Wei

2003-07-01

198

38 CFR 11.128 - Veteran dies without having filed application for final settlement.  

Code of Federal Regulations, 2011 CFR

...Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS LOANS BY BANKS ON AND PAYMENT OF ADJUSTED SERVICE CERTIFICATES Application for Payment of Adjusted Service Certificate Under the World War Adjusted Compensation Act, As Amended (pub. L....

2011-07-01

199

Effects of firing cycle and surface finishing on distortion of metal ceramic castings.  

PubMed

The "as-cast" fit of metal ceramic restorations has been reported to deteriorate during the high-temperature firing cycles used for application of porcelain veneer. In this study, thermocycling and surface finishing or cold working were examined for their effects on marginal adaptation of metal ceramic castings. Methods for minimizing the loss of marginal adaptation were evaluated, and casting variables were eliminated by construction of acrylic resin measuring dies directly in the restorations. Thermocycling of metal ceramic restorations resulted in increased marginal openings, and all of the loss of marginal fit occurred during the first thermocycling of the alloy. The restorations that were cold worked and then oxidized by conventional manipulation had substantially more marginal opening than any other group. A fourfold, statistically significant improvement (p < 0.001) in the marginal adaptation of a metal ceramic restoration was observed when the initial thermal cycle was completed before the specimens were finished. PMID:8809252

Campbell, S D; Sirakian, A; Pelletier, L B; Giordano, R A

1995-11-01

200

A comparative study of the centrifugal and vacuum-pressure techniques of casting removable partial denture frameworks.  

PubMed

A study was undertaken to evaluate two techniques for casting accuracy on removable partial denture frameworks: centrifugal casting and vacuum-pressure casting. A standard metal die with predetermined reference points in a horizontal plane was duplicated in refractory investment. The casts were waxed, and castings of nickel-chrome alloy were fabricated by the two techniques. Both the casts and the castings were measured between the reference points with a measuring microscope. With both casting methods, the differences between the casts and the castings were significant, but no significant differences were found between castings produced by the two techniques. Vertical measurements at three designated points also showed no significant differences between the castings. Our findings indicate that dental laboratories should be able to use the vacuum-pressure method of casting removable partial denture frameworks and achieve accuracy similar to that obtained by the centrifugal method of casting. PMID:7007622

Shanley, J J; Ancowitz, S J; Fenster, R K; Pelleu, G B

1981-01-01

201

Project CAST.  

ERIC Educational Resources Information Center

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…

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

202

Alloy Design and Development of Cast Cr-W-V Ferritic Steels for Improved High-Temperature Strength for Power Generation Applications  

SciTech Connect

Economic and environmental concerns demand that the power-generation industry seek increased efficiency for gas turbines. Higher efficiency requires higher operating temperatures, with the objective temperature for the hottest sections of new systems {approx} 593 C, and increasing to {approx} 650 C. Because of their good thermal properties, Cr-Mo-V cast ferritic steels are currently used for components such as rotors, casings, pipes, etc., but new steels are required for the new operating conditions. The Oak Ridge National Laboratory (ORNL) has developed new wrought Cr-W-V steels with 3-9% Cr, 2-3% W, 0.25% V (compositions are in wt.%), and minor amounts of additional elements. These steels have the strength and toughness required for turbine applications. Since cast alloys are expected to behave differently from wrought material, work was pursued to develop new cast steels based on the ORNL wrought compositions. Nine casting test blocks with 3, 9, and 11% Cr were obtained. Eight were Cr-W-V-Ta-type steels based on the ORNL wrought steels; the ninth was COST CB2, a 9Cr-Mo-Co-V-Nb cast steel, which was the most promising cast steel developed in a European alloy-development program. The COST CB2 was used as a control to which the new compositions were compared, and this also provided a comparison between Cr-W-V-Ta and Cr-Mo-V-Nb compositions. Heat treatment studies were carried out on the nine castings to determine normalizing-and-tempering treatments. Microstructures were characterized by both optical and transmission electron microscopy (TEM). Tensile, impact, and creep tests were conducted. Test results on the first nine cast steel compositions indicated that properties of the 9Cr-Mo-Co-V-Nb composition of COST CB2 were better than those of the 3Cr-, 9Cr-, and 11Cr-W-V-Ta steels. Analysis of the results of this first iteration using computational thermodynamics raised the question of the effectiveness in cast steels of the Cr-W-V-Ta combination versus the Cr-Mo-V-Nb combination in COST CB2. To explore this question, nine more casting test blocks, four 3Cr steels and five 11Cr steels were purchased, and microstructure and mechanical properties studies similar to those described above for the first iteration of test blocks were conducted. Experimental results from the second iteration indicated that 11 Cr steels with excellent properties are possible. The 11Cr-1.5Mo-V-Nb steels were superior to 11Cr-2W-V-Ta steels, and it appears the former class of steels can be developed to have tensile and creep properties exceeding those of COST CB2. The W-Nb combination in an 11Cr-2W-V-Nb steel had tensile and short-time creep properties at 650 C better than the 11Cr-1.5Mo-V-Nb steels, although long-time low-stress properties may not be as good because of Laves phase formation. Based on the results, the next step in the development of improved casting steels involves acquisition of 11Cr-1.5Mo-V-Nb-N-B-C and 11Cr-2W-V-Nb-N-B-C steels on which long-term creep-rupture tests (>10,000 h) be conducted. For better oxidation and corrosion resistance, development of 11Cr steels, as opposed to a 9Cr steels, such as COST CB2, are important for future turbine designs that envision operating temperatures of 650 C.

Klueh, R.L.; Maziasz, P.J.; Vitek, J.M.; Evans, N.D.; Hashimoto, N.

2006-09-23

203

Pb-Free Glass Paste: A Metallization-Free Die-Attachment Solution for High-Temperature Application on Ceramic Substrates  

NASA Astrophysics Data System (ADS)

A lead-free glass frit paste as a die-attach material for high-temperature microelectronic application is proposed in this study. The glass paste containing Bi-based powder with a moderate amount of solvent was used for joining Si dice on ceramic substrates without any metallization preparation for either of the bonding surfaces. The die was bonded to a ceramic substrate at 430°C for 10 min. The study focuses on the mechanical and microstructural characterization of the joints with Si dice on two different types of ceramic substrate. Shear strength measurements were carried out at both ambient and 250°C to evaluate room- and high-temperature performance. Furthermore, the effect of aging at 300°C for 500 h on the mechanical properties is presented. The results of the mechanical and microstructural characterization demonstrate that low-temperature glass frit bonding is an effective die-attach method for harsh-environment electronic packaging.

Sharif, Ahmed; Lim, Jun zhang; Made, Riko I.; Lau, Fu Long; Phua, Eric Jian Rong; Lim, Ju Dy; Wong, Chee Cheong; Gan, Chee Lip; Chen, Zhong

2013-08-01

204

Normalizing of castings in a water-air cooling chamber  

SciTech Connect

The results of modernizing a water-air cooling chamber for normalizing castings of complex shape and steel of different classes are considered. It is economically desirable to modernize existing units with the aim of providing regular water-air cooling schedules which replace the ecologically harmful and fire hazard operation of oil quenching for large articles (dies, shafts, body castings, etc.)

Nemzer, N.A.; Nemzer, G.G.; Kovalev, A.G.

1995-05-01

205

Casting methods  

DOEpatents

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.

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

2012-12-18

206

Determination of heat transfer coefficients by extrapolation and numerical inverse methods in squeeze casting of magnesium alloy AM60  

Microsoft Academic Search

In this work, a different wall-thickness 5-step (with thicknesses as 3, 5, 8, 12, 20mm) casting mold was designed, and squeeze casting of magnesium alloy AM60 was performed under an applied pressure 30, 60 and 90MPa in a hydraulic press. The casting–die interfacial heat transfer coefficients (IHTC) in the 5-step casting were determined based on thermal histories throughout the die

Zhizhong Sun; Henry Hu; Xiaoping Niu

2011-01-01

207

Correlating Hardness Retention and Phase Transformations of Al and Mg Cast Alloys for Aerospace Applications  

NASA Astrophysics Data System (ADS)

The methodology based on correlating hardness and phase transformations was developed and applied to determine the maximum temperature of hardness retention of selected Al-based and Mg-based alloys for aerospace applications. The Al alloys: A356, F357, and C355 experienced 34-66% reduction of the initial hardness, in comparison to 4-22% hardness reduction observed in Mg alloys: QE22A, EV31A, ZE41A, and WE43B after the same annealing to 450 °C. For Al alloys the hardness reduction showed a steep transition between 220 and 238 °C. In contrast, Mg alloys showed a gradual hardness decrease occurring at somewhat higher temperatures between 238 and 250 °C. The hardness data were correlated with corresponding phase transformation kinetics examined by dilatometer and electrical resistivity measurements. Although Mg alloys preserved hardness to higher temperatures, their room temperature tensile strength and hardness were lower than Al alloys. The experimental methodology used in the present studies appears to be very useful in evaluating the softening temperature of commercial Al- and Mg-based alloys, permitting to assess their suitability for high-temperature applications.

Kasprzak, W.; Czerwinski, F.; Niewczas, M.; Chen, D. L.

2015-03-01

208

76 FR 5840 - The Basic Aluminum Castings Co., Cleveland, OH; Notice of Revised Determination on Reconsideration  

Federal Register 2010, 2011, 2012, 2013, 2014

...Administration [TA-W-73,091] The Basic Aluminum Castings Co., Cleveland, OH; Notice...workers and former workers of The Basic Aluminum Castings Co., Cleveland, Ohio (subject...employment related to the production of aluminum die castings. New information...

2011-02-02

209

Casting the Spirit: A Handmade Legacy  

ERIC Educational Resources Information Center

This article discusses how an art therapist working in a hospital palliative care unit has incorporated a ritual of hand casting to help bring closure to dying patients and family members who are grieving as death approaches. The finished hand sculptures depict the hands of the patients and, sometimes, of their loved ones. They are faithful and…

Rutenberg, Mona

2008-01-01

210

Clamshell Casting! Stefanie Wuhrer  

E-print Network

Clamshell Casting! By Stefanie Wuhrer A thesis submitted to the Faculty of Graduate Studies and Research acceptance of the thesis, Clamshell Casting! submitted by Stefanie Wuhrer Douglas Howe (Director is casting, where liquid is poured into a cast and the cast is removed once the liquid has hardened. We

Wuhrer, Stefanie

211

Casting materials  

DOEpatents

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.

Chaudhry, Anil R. (Xenia, OH); Dzugan, Robert (Cincinnati, OH); Harrington, Richard M. (Cincinnati, OH); Neece, Faurice D. (Lyndurst, OH); Singh, Nipendra P. (Pepper Pike, OH)

2011-06-14

212

Development of an inverse heat conduction model and its application to determination of heat transfer coefficient during casting solidification  

NASA Astrophysics Data System (ADS)

The interfacial heat transfer coefficient (IHTC) is required for the accurate simulation of heat transfer in castings especially for near net-shape processes. The large number of factors influencing heat transfer renders quantification by theoretical means a challenge. Likewise experimental methods applied directly to temperature data collected from castings are also a challenge to interpret because of the transient nature of many casting processes. Inverse methods offer a solution and have been applied successfully to predict the IHTC in many cases. However, most inverse approaches thus far focus on use of in-mold temperature data, which may be a challenge to obtain in cases where the molds are water-cooled. Methods based on temperature data from the casting have the potential to be used however; the latent heat released during the solidification of the molten metal complicates the associated IHTC calculations. Furthermore, there are limits on the maximum distance the thermocouples can be placed from the interface under analysis. An inverse conduction based method have been developed, verified and applied successfully to temperature data collected from within an aluminum casting in proximity to the mold. A modified specific heat method was used to account for latent heat evolution in which the rate of change of fraction solid with temperature was held constant. An analysis conducted with the inverse model suggests that the thermocouples must be placed no more than 2 mm from the interface. The IHTC values calculated for an aluminum alloy casting were shown to vary from 1,200 to 6,200 Wm-2 K-1. Additionally, the characteristics of the time-varying IHTC have also been discussed.

Zhang, Liqiang; Reilly, Carl; Li, Luoxing; Cockcroft, Steve; Yao, Lu

2014-07-01

213

Superplastic Response of Continuously Cast AZ31B Magnesium Sheet Alloys  

NASA Astrophysics Data System (ADS)

Magnesium sheet is typically produced for commercial applications with the traditional DC-ingot casting method. As a result of the hexagonal close-packed crystallographic structure in magnesium, multiple rolling passes and annealing steps are required to reduce the thickness of the ingots. Thus, high fabrication costs characterize the creation of magnesium sheet suitable for common forming operations. Recently, continuous casting (CC) technology, where molten metal is solidified directly into sheet form, has been applied to magnesium alloys; this method has shown the potential to significantly reduce the cost of fabricating magnesium sheet alloys. In order to understand the viability of the CC process, a study was conducted to investigate the superplastic potential of alloys produced by this method. This study focused on AZ31B Mg that was continuously-cast on twin-roll casters from three different suppliers. These three materials were compared with a production DC-cast AZ31B alloy in terms of microstructure, elevated-temperature tensile properties, and superplastic forming response. The data from this study found that microstructural features such as grain size and segregation can significantly affect the forming response. Additionally, the CC alloys can have equivalent or superior SPF response compared to DC-cast alloys, as demonstrated in both elevated temperature tensile tests and superplastic forming trials using a rectangular pan die.

Boileau, J. M.; Friedman, P. A.; Houston, D. Q.; Luckey, S. G.

2010-06-01

214

The application of a probabilistic particle model for turbulent combustion modelling in combustors. (German Title: Die Anwendung eines probabilistischen Partikelmodells für die Modellierung der turbulenten Verbrennung in Brennkammern)  

NASA Astrophysics Data System (ADS)

The modeling of combustion phenomena in turbulent flows is an important requirement to calculate the effects on the underlying flow field and thus to use the results for design studies and optimization processes in technical applications. Complex chemical systems arise due to the large amount of species participating in combustion reactions as well as multiple reaction paths which are represented by a set of reaction equations. These systems have to be solved with suitable numerical techniques and must consider the influence of turbulence in the mean transport equations, respectively. Compared to the time scales in the flow, chemical reactions occur on a more expanded range of time at a molecular level. This effect reflects in the formulation of the equations for the calculation of chemical reaction rates, which are given in a Lagrangian formulation and therefore only depends on time. In practical cases specific combustion models are used depending on the combustion regime which is associated within an application. In this thesis a combustion model for turbulence chemistry interactions is presented, which can be used, independently of the combustion regime, for both diffusion and premixed flames as well as for partially premixed flames in realistic combustors. With the aid of the model the mean chemical source terms can be coupled to the species transport equations and the energy equation of the commercial CFD - solver FLUENT®. This is done within the solver by a user-friendly interface, the so-called User Defined Functions (UDF). Transport equations for each specie progressing in the chemical reactions are solved and its source terms are calculated with the aid of a detailed reaction mechanism. In the presented model the calculation of the mean values is performed by coupling a Lagrangian solution procedure with an Eulerian finite volume solver. A very large amount of individual particles are considered where for each particle additional Lagrangian equations have to be solved. The basic principle of the model is the calculation of fluid particle trajectories, which are moved through the flow field. Exchange processes with the surrounding fluid as well as chemical reactions occur to each fluid particle on its way through the flow field. The surrounding fluid is represented by the mean flow nearby the particle and is locally defined by a computational cell. Exchange processes have to be modeled. For this purpose a very simple model known as the IEM (Intermediate Exchange by the Mean) model is used. The chemical source term is given in a closed formulation and can be directly calculated from particle data. This is one of the main advantages of the described procedure. From an ensemble of fluid particles the mean source terms after each numerical time step can be calculated and are passed to the CFD-solver. This procedure implies the solution of the unsteady transport equations in FLUENT. The presented model is based on a model, which is known as PEUL (PEUL - Probabilistique Eulerienne Lagrangienne) in literature and was applied for the first time in an unsteady coupling of the Lagrangian particle solver and the Eulerian flow solver. However, the computational effort is very high due to the high amount of particles which are necessary for the calculation. In this study three different applications are investigated: a turbulent methane-air jetflame, a premixed lean combustion of methane under FLOX® operation conditions as well as a diffusion flame in a generic combustor for the combustion of syntesis gas. The results are presented and show in general a good consistency with the experimental data. Nevertheless, they also offer some shortcomings, which are discussed. A lot of computational efforts limits the model in very large configurations.

Aumeier, Thomas

2011-12-01

215

Die Wärmeleitfähigkeit von Alkoholen  

Microsoft Academic Search

Die Wärmeleitfähigkeit eines Mediums ist in der Nähe seiner Grenzflächen kleiner als im Innern, weil die Reflexionen der die Leitung bewirkenden Partikeln an den Randflächen eine Abnahme der mittleren freien Weglänge verursachen. Dies vermindert die Leitfähigkeit einer Probe meßbar, wenn die mittlere freie Weglänge mindestens einer wesentlich am Transport beteiligten Partikelart mit der Abmessung der Probe in der Flußrichtung vergleichbar

H. Poltz; R. Jugel

1968-01-01

216

Wege in die Zukunft  

NASA Astrophysics Data System (ADS)

Die Zukunft stellt große Herausforderungen an die Arbeit der Deutschen Statistischen Gesellschaft. Sie betreffen die gestiegenen Anforderungen der Nutzer von Statistik, die Kommunikationsmöglichkeiten des Internets sowie die Dynamik der statistischen Wissenschaften und ihrer Anwendungsgebiete. Das Kapitel 5 beschreibt, wie sich die Gesellschaft diesen Herausforderungen stellt und welche Ziele sie sich in der wissenschaftlichen Zusammenarbeit und im Kampf gegen das Innumeratentum gesetzt hat.

Kauermann, Göran; Mosler, Karl

217

The effect of axial grooves on the resistance form of cast restorations.  

PubMed

Fifteen sets of castings were fabricated to machined stainless steel dies of 5 degrees, 10 degrees, and 15 degrees of taper and 3, 4, 6, 8, and 10 mm of preparation length. Each casting was loaded vertically on its sloped surface in an attempt to unseat the casting. Only the castings of 3 and 4 mm of preparation length and 10 degrees and 15 degrees taper were unseated. Two experiments were performed on these four sets of dies to test parallel proximal and parallel buccolingual grooves. Dies with grooves oriented on the proximal surfaces provided complete resistance to horizontal dislodgement, whereas dies with grooves oriented on the buccal and lingual surfaces provided only partial resistance to horizontal displacement and potential failure of the castings. PMID:363771

Woolsey, G D; Matich, J A

1978-12-01

218

Thin Wall Iron Castings  

SciTech Connect

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.

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

2001-10-31

219

Application of high speed slurry flow finishing method for finishing of inner wall of fine hole die  

Microsoft Academic Search

In order to warrant the quality of drawn metal wires, the inner wall of the hole die which has been used in the drawing of metal wire, has been usually finished by hand work for a long time using a bar daubed the kneaded paste containing diamond powder. High speed slurry flow finishing method which has been recently developed for

Toshiji Kurobe; Yoshinori Yamada; Keiichiro Yamamoto

2002-01-01

220

Identification of anisotropic Hill criteria from the channel die compression test. Application to a normal anisotropy of zirconium 702alpha  

Microsoft Academic Search

During the last years the study of the plastic deformation modes and the anisotropic mechanical behavior of zirconium alloys have been the subject of many investigations. This paper deals with a phenomenological identification of an anisotropic Hill constitutive equation of zirconium 702alpha samples using channel die compression at room temperature. Generally, by considering the different possible orientations of the samples

A. Gavrus; H. Francillette

2003-01-01

221

Optimization of Squeeze Casting for Aluminum Alloy Parts  

SciTech Connect

This study was initiated with the installation of a new production size UBE 350 Ton VSC Squeeze Casting system in the Metal Casting Laboratory at Case Western University. A Lindberg 75k W electrical melting furnace was installed alongside. The challenge of installation and operation of such industrial-size equipment in an academic environment was met successfully. Subsequently, a Sterling oil die heater and a Visi-Track shot monitoring system were added. A significant number of inserts were designed and fabricated over the span of the project, primarily for squeeze casting different configurations of test bars and plates. A spiral ''ribbon insert'' for evaluation of molten metal fluidity was also fabricated. These inserts were used to generate a broad range of processing conditions and determine their effect on the quality of the squeeze cast parts. This investigation has studied the influence of the various casting variables on the quality of indirect squeeze castings primarily of aluminum alloys. The variables studied include gating design, fill time and fill patter, metal pressure and die temperature variations. The quality of the die casting was assessed by an analysis of both their surface condition and internal soundness. The primary metal tested was an aluminum 356 alloy. In addition to determining the effect of these casting variables on casting quality as measured by a flat plate die of various thickness, a number of test bar inserts with different gating designs have been inserted in the squeeze casting machine. The mechanical properties of these test bars produced under different squeeze casting conditions were measured and reported. The investigation of the resulting properties also included an analysis of the microstructure of the squeeze castings and the effect of the various structural constituents on the resulting properties. The main conclusions from this investigation are as follows: The ingate size and shape are very important since it must remain open until the casting is solidified and pressure is maintained on the solidifying casting. Fanned gates, particularly on the smaller section castings avoid jetting effects at the ingate end. The fan type ingate helps accomplish a rapid fill without high velocities. The molten metal has to fill the cavity before localized solidification occurs. This is best accomplished with a larger ingate to attain rapid filling without excessive velocity or jetting that occurs at high metal velocities. Straight gates are prone to case jetting of the metal stream even a low velocities. Fanned gates allow use of higher fill velocity without excessive jetting. A higher metal pressure provides a more complete fill of the die including improved compensation for solidification shrinkage. With the proper filling pattern, ingates, overflows and die temperature for a given die, very good tensile properties can be attained in squeeze casting. In general, the smaller squeeze castings require higher die temperatures. Computer models using the UES Procast and MagmaSoft finite element software can, after suitable adjustments, predict the flow pattern in the die cavity.

David Schwam; John F. Wallace; Qingming Chang; Yulong Zhu

2002-07-30

222

Segmentation of Cast Shadows from Moving Objects  

E-print Network

including cast shadows, is obtained using a high resolution digital video camera, in a typical surveillance shadows, when detecting moving objects in systems for automated video surveillance. It is assumed in an outdoor surveillance application. Cast shadows reduce the general ability of robust classication

223

Beamte, die sich als \\  

Microsoft Academic Search

7 Sicherheitspolitik ist also keineswegs wertneutral. Dies betrifft sowohl das Ziel dieser Politik, als auch die Mittel, deren man sich zum Erreichen dieses Ziels bedient. Werden etwa territoriale Integrität und Souveränitäts- wahrung als Kernwerte nationaler Sicherheit angenommen, ent- spricht dies einer normativen politischen Ausrichtung. Im Vorder- grund steht damit die Bewahrung des bestehenden National- staats und nicht beispielsweise die Bildung

Walter Lippmann

224

Evaluation of Heat Checking and Washout of Heat Resistant Superalloys and Coatings for Die inserts  

SciTech Connect

This project had two main objectives: (1) To design, fabricate and run a full size test for evaluating soldering and washout in die insert materials. This test utilizes the unique capabilities of the 350 Ton Squeeze Casting machine available in the Case Meal Casting Laboratory. Apply the test to evaluate resistance of die materials and coating, including heat resistant alloys to soldering and washout damage. (2) To evaluate materials and coatings, including heat resistant superalloys, for use as inserts in die casting of aluminum alloys.

David Schwam; John F. Wallace; Yulong Zhu; Edward Courtright; Harold Adkins

2005-01-30

225

The effect of four sprue shapes on the quality of cobalt-chromium cast removable partial denture frame-works  

PubMed Central

Statement of Problem: Sprue design is a factor that controls the velocity and adequate supply of metal to the mould. Currently various manufacturers recommend different shapes of sprue, which have not been advocated in textbooks and literature is lacking for their routine applications. Purpose: This in vitro study was carried out to determine the efficacy of four sprue shapes in producing complete, void free cobalt-chrome removable partial denture frameworks. Materials and Methods: A brass metal die with a Kennedy class III, modification 1, partially edentulous arch was used and four sprue shapes (Group A-Ribbon, Group B-Square, Group C-Round and Group D- Round with reservoir) were evaluated. 40 refractory casts were made, 10 wax patterns for each sprue design were waxed up, invested with phosphate bonded investment material and castings done with induction casting machine by the same operator under standardized protocols. The cast frameworks were evaluated for 1. The defects observed visually before finishing and polishing procedures, 2. Fit on the master die as seen with naked eye and 3. Defects on radiographic evaluation. Data were tabulated and statistically analyzed with 1-way ANOVA followed by Student ‘t’ test. Results: The results differed significantly (P < 0.0001) between the Groups with maximum defects in the castings of Group A followed in decreasing order by Group B, Group C and Group D. When comparing between the Groups (P < 0.05), the defects in Groups C and D was significantly lower than Group A and Group B. Conclusions: Round sprues with reservoir produced most satisfactory fit of castings with minimum number of internal and external defects. PMID:24014998

Viswambaran, M.; Agarwal, S. K.

2013-01-01

226

Task 7: Die soldering during host site testing. Final report, January1--December 31, 1997  

SciTech Connect

To provide industrial confirmation of laboratory results produced in Task 6 of this project, five industrial trials were organized with cooperative die casters in the USA. Components cast during these trials ranged from functional electronic heat sinks to decorative household plumbing components. Whereas laboratory work indicated that die temperature and draft angle were the most important process factors influencing solder accumulation, it was not possible to vary draft angle on the established production dies used for these trials. Substantial variations in die temperature were realized however and also die surface conditions were varied, confirming the influence of a secondary variable in the laboratory investigation. Substantial evidence from the trials indicated that die surface temperature is the most important factor for controlling solder build up. The surface roughness of the die casting die greatly influenced the number of castings that could be run before solder initially appeared. Development of careful thermal management techniques, now judged to be beyond the capabilities of most US die casters, will be necessary to control incidences of die soldering found in typical production. Thermal control will involve both control of the bulk die temperature through use of thermally controlled cooling lines, and also regulation of surface temperature by well controlled cooling lines, and also regulation of surface temperature by well controlled die spraying (lubrication) techniques. Further research, development and technology transfer to enhance thermal control capabilities of US die casters is recommended.

Goodwin, F.E. [International Lead Zinc Research Organization, Inc., Research Triangle Park, NC (United States); Walkington, W.G. [Walkington (William G.), Cottage Grove, WI (United States)

1998-01-31

227

DIE Deflection Modeling: Empirical Validation and Tech Transfer  

SciTech Connect

This report summarizes computer modeling work that was designed to help understand how the die casting die and machine contribute to parting plane separation during operation. Techniques developed in earlier research (8) were applied to complete a large computational experiment that systematically explored the relationship between the stiffness of the machine platens and key dimensional and structural variables (platen area covered, die thickness, platen thickness, thickness of insert and the location of the die with respect to the platen) describing the die/machine system. The results consistently show that there are many significant interactions among the variables and it is the interactions, more than the individual variables themselves, which determine the performance of the machine/die system. That said, the results consistently show that it is the stiffness of the machine platens that has the largest single impact on die separation.

R. Allen Miller

2003-05-28

228

Berthold Auerbach Die Kriegspfeife.  

E-print Network

den Schwarzwald zo- gen bald die �sterreicher mit ihren wei�en Wämm- sern, bald die Franzosen mit die Bayern, Würtember- ger, Hessen, in allerlei Gestalt. Der Schwarzwald war das allzeit offene Thor

Prodinger, Helmut

229

Die Darwinsche Theorie und die Eukaryoten  

E-print Network

Geologe Charles Darwin 1859 in der Darwin Theorie. 6.1 Die Darwin-Theorie der Evolution Lebewesen kämpfen. Nach der Darwin-Theorie, wie sie heute formuliert wird, müssen sich mutierte Organismen einem höherer Farbkontrast zu einer besseren Wahrnehmung durch Fressfeinde führt. Die Darwin-Theorie erklärt die

Ulmschneider, Peter

230

Die großen Zeppeline: Die Geschichte des Luftschiffbaus  

NASA Astrophysics Data System (ADS)

Über die glanzvolle Zeit der Zeppeline sind viele Bücher erschienen, die vorwiegend den Einsatz der Luftschiffe in Frieden und Krieg schildern. Nur wenige wissen, dass die Baugeschichte der Zeppeline eine der faszinierendsten Phasen der modernen Technik ist. Peter Kleinheins hat dieses Geschehen sachkundig aufgearbeitet und zusammengestellt. Entstanden ist eine reich illustrierte Dokumentation in einer interessanten Mischform aus zeitgenössischen Berichten und hochwertigen Originalquellen.

Kleinheins, Peter; Meighörner, Wolfgang

231

Analysis of cryotherapy penetration: a comparison of the plaster cast, synthetic cast, Ace wrap dressing, and Robert-Jones dressing.  

PubMed

Four groups were studied to determine the cooling effect at skin level of ice application over common ankle bandages and casts. The plaster cast, synthetic cast, and Ace wrap dressing groups had 18 participants and the Robert-Jones dressing group had four participants. In a standardized fashion, ice bags were applied over each bandage or cast and skin temperatures were measured with a thermocouple over a 90-min period. The average final skin temperature was 16.5 degrees in the plaster cast, 18.8 degrees in the synthetic cast, 21.2 degrees in the Ace wrap dressing, and 28.7 degrees in the Robert-Jones dressing. The temperature curves showed that ice application effectively decreased skin temperatures through the plaster cast, synthetic cast, and Ace wrap dressing. The cooler temperature did not adequately penetrate the Robert-Jones dressing. PMID:8821285

Weresh, M J; Bennett, G L; Njus, G

1996-01-01

232

A Benchmark Study on Casting Residual Stress  

SciTech Connect

Stringent regulatory requirements, such as Tier IV norms, have pushed the cast iron for automotive applications to its limit. The castings need to be designed with closer tolerances by incorporating hitherto unknowns, such as residual stresses arising due to thermal gradients, phase and microstructural changes during solidification phenomenon. Residual stresses were earlier neglected in the casting designs by incorporating large factors of safety. Experimental measurement of residual stress in a casting through neutron or X-ray diffraction, sectioning or hole drilling, magnetic, electric or photoelastic measurements is very difficult and time consuming exercise. A detailed multi-physics model, incorporating thermo-mechanical and phase transformation phenomenon, provides an attractive alternative to assess the residual stresses generated during casting. However, before relying on the simulation methodology, it is important to rigorously validate the prediction capability by comparing it to experimental measurements. In the present work, a benchmark study was undertaken for casting residual stress measurements through neutron diffraction, which was subsequently used to validate the accuracy of simulation prediction. The stress lattice specimen geometry was designed such that subsequent castings would generate adequate residual stresses during solidification and cooling, without any cracks. The residual stresses in the cast specimen were measured using neutron diffraction. Considering the difficulty in accessing the neutron diffraction facility, these measurements can be considered as benchmark for casting simulation validations. Simulations were performed using the identical specimen geometry and casting conditions for predictions of residual stresses. The simulation predictions were found to agree well with the experimentally measured residual stresses. The experimentally validated model can be subsequently used to predict residual stresses in different cast components. This enables incorporation of the residual stresses at the design phase along with external loads for accurate predictions of fatigue and fracture performance of the cast components.

Johnson, Eric M. [John Deere -- Moline Tech Center; Watkins, Thomas R [ORNL; Schmidlin, Joshua E [ORNL; Dutler, S. A. [MAGMA Foundry Technologies, Inc.

2012-01-01

233

[Application of gypsum-bonded investment containing niobium carbide on casting of alloy for metal-ceramic restoration].  

PubMed

Experimental gypsum-bonded investments containing 0.5-5.0 wt% NbC were prepared by mechanical mixing of each powder. Setting and thermal expansion measurement, compressive strength and casting accuracy for Ni-Cr alloy for metal-ceramic restoration were investigated. Analysis of NbC during heating was carried out by X-ray diffraction, TG-DTA and SEM. NbC was oxidized to Nb2O5 with a volume change between 300-600 degrees C, as in the following equation: 2NbC + 4 1/2O2----Nb2O5 + 2CO2 The theoretical volume of 1/2Nb2O5 calculated from the lattice constants according to JCPDS file was approximately 4 times larger than that of NbC. The experimental investments of 70 wt% cristobalite and 30 wt% gypsum containing 2.0, 3.0 and 5.0 wt% NbC showed large thermal expansion of 7.0, 10.0 and 13.0% respectively. The investment containing 2.0 wt% NbC showed nearly the same casting accuracy for Ni-Cr alloys for metal-ceramic restoration as the commercial phosphate-bonded investment. PMID:2134827

Tsuruta, S; Ban, S; Hasegawa, J; Hayashi, S; Iiyama, K; Yamamura, Y

1990-07-01

234

INTERIOR VIEW WITH CASTING MACHINE AND CASTING FOREMAN OBSERVING OPERATION ...  

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

INTERIOR VIEW WITH CASTING MACHINE AND CASTING FOREMAN OBSERVING OPERATION TO ENSURE MAXIMUM PRODUCTION AND QUALITY. - McWane Cast Iron Pipe Company, Pipe Casting Area, 1201 Vanderbilt Road, Birmingham, Jefferson County, AL

235

Computer simulation applied to jewellery casting: challenges, results and future possibilities  

NASA Astrophysics Data System (ADS)

Computer simulation has been successfully applied in the past to several industrial processes (such as lost foam and die casting) by larger foundries and direct automotive suppliers, while for the jewelry sector it is a procedure which is not widespread, and which has been tested mainly in the context of research projects. On the basis of a recently concluded EU project, the authors here present the simulation of investment casting, using two different softwares: one for the filling step (Flow-3D®), the other one for the solidification (PoligonSoft®). A work on material characterization was conducted to obtain the necessary physical parameters for the investment (used for the mold) and for the gold alloys (through thermal analysis). A series of 18k and 14k gold alloys were cast in standard set-ups to have a series of benchmark trials with embedded thermocouples for temperature measurement, in order to compare and validate the software output in terms of the cooling curves for definite test parts. Results obtained with the simulation included the reduction of micro-porosity through an optimization of the feeding channels for a controlled solidification of the metal: examples of the predicted porosity in the cast parts (with metallographic comparison) will be shown. Considerations on the feasibility of applying the casting simulation in the jewelry sector will be reached, underlining the importance of the software parametrization necessary to obtain reliable results, and the discrepancies found with the experimental comparison. In addition an overview on further possibilities of application for the CFD in jewellery casting, such as the modeling of the centrifugal and tilting processes, will be presented.

Tiberto, Dario; Klotz, Ulrich E.

2012-07-01

236

Magnesium-lithium casting alloys  

NASA Technical Reports Server (NTRS)

The strength properties of magnesium-lithium alloys at room, low, and high temperatures are investigated. It is found that the alloys may have practical application at ambient temperatures up to 100 C, that negative temperatures have a favorable influence on the alloy strength, and that cyclic temperature variations have practically no effect on the strength characteristics. The influence of chemical coatings on corrosion resistance of the MgLi alloys is examined. Several facilities based on pressure casting machines, low-pressure casting machines, and magnetodynamic pumps were designed for producing MgLi alloy castings. Results were obtained for MgLi alloys reinforced with fibers having a volumetric content of 15%.

Latenko, V. P.; Silchenko, T. V.; Tikhonov, V. A.; Maltsev, V. P.; Korablin, V. P.

1974-01-01

237

75 FR 69470 - JL French Automotive Castings, LLC, Including On-Site Leased Workers From Labor Ready and Seek...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Administration [TA-W-70,143] JL French Automotive Castings, LLC, Including...4, 2009, applicable to workers of JL French Automotive Castings LLC, including on-site...the Sheboygan, Wisconsin location of JL French Automotive Castings LLC. The...

2010-11-12

238

40 CFR 63.5820 - What are my options for meeting the standards for continuous lamination/casting operations?  

Code of Federal Regulations, 2010 CFR

...meeting the standards for continuous lamination/casting operations? 63.5820...lamination line and each continuous casting line complies with the applicable...continuous lamination and continuous casting lines combined, comply...

2010-07-01

239

40 CFR 63.5820 - What are my options for meeting the standards for continuous lamination/casting operations?  

Code of Federal Regulations, 2011 CFR

...the standards for continuous lamination/casting operations? 63.5820 Section 63...the standards for continuous lamination/casting operations? You must use one or more...continuous lamination line and each continuous casting line complies with the applicable...

2011-07-01

240

40 CFR 63.5820 - What are my options for meeting the standards for continuous lamination/casting operations?  

Code of Federal Regulations, 2014 CFR

...the standards for continuous lamination/casting operations? 63.5820 Section 63...the standards for continuous lamination/casting operations? You must use one or more...continuous lamination line and each continuous casting line complies with the applicable...

2014-07-01

241

40 CFR 63.5820 - What are my options for meeting the standards for continuous lamination/casting operations?  

Code of Federal Regulations, 2013 CFR

...the standards for continuous lamination/casting operations? 63.5820 Section 63...the standards for continuous lamination/casting operations? You must use one or more...continuous lamination line and each continuous casting line complies with the applicable...

2013-07-01

242

40 CFR 63.5820 - What are my options for meeting the standards for continuous lamination/casting operations?  

Code of Federal Regulations, 2012 CFR

...the standards for continuous lamination/casting operations? 63.5820 Section 63...the standards for continuous lamination/casting operations? You must use one or more...continuous lamination line and each continuous casting line complies with the applicable...

2012-07-01

243

Vacuum casting of thick polymeric films  

NASA Technical Reports Server (NTRS)

Bubble formation and layering, which often plague vacuum-evaporated films, are prevented by properly regulating process parameters. Vacuum casting may be applicable to forming thick films of other polymer/solvent solutions.

Cuddihy, E. F.; Moacanin, J.

1979-01-01

244

Evaluation of Die-Attach Bonding Using High-Frequency Ultrasonic Energy for High-Temperature Application  

NASA Astrophysics Data System (ADS)

Room-temperature die-attach bonding using ultrasonic energy was evaluated on Cu/In and Cu/Sn-3Ag metal stacks. The In and Sn-3Ag layers have much lower melting temperatures than the base material (Cu) and can be melted through the heat generated during ultrasonic bonding, forming intermetallic compounds (IMCs). Samples were bonded using different ultrasonic powers, bonding times, and forces and subsequently aged at 300°C for 500 h. After aging, die shear testing was performed and the fracture surfaces were inspected by scanning electron microscopy. Results showed that the shear strength of Cu/In joints reached an upper plateau after 100 h of thermal aging and remained stable with aging time, whereas that of the Cu/Sn-3Ag joints decreased with increasing aging time. ?-Cu7In4 and (Cu,Au)11In9 IMCs were observed at the Cu/In joint, while Cu3Sn and (Ag,Cu)3Sn IMCs were found at the Cu/Sn-3Ag joint after reliability testing. As Cu-based IMCs have high melting temperatures, they are highly suitable for use in high-temperature electronics, but can be formed at room temperature using an ultrasonic approach.

Lee, Jong-Bum; Aw, Jie-Li; Rhee, Min-Woo

2014-09-01

245

An experimental study on the development and application of ultra-high-accuracy and high-speed groove die set  

NASA Astrophysics Data System (ADS)

This research designed and developed a groove type die set which improved life span of the die set by eliminating pointcontacts of steel balls with the guide post. The guide post consisted of a steel-ball retainer, a steel-ball retainer stopper, a guide bush, a guide pin, a snap ring, and a spring. The steel-ball retainer has 72 holes with 8 columns of 9 holes in each column. The inner surface of the guide bush was grinded (surface roughness: Ra = 0.2?m, accuracy: 0 ~ -0.002 mm) after NC turning and it was treated with heat. Also, a line of small intermediate pocket was processed inside of the guide bush for lubrication and elimination of foreign materials. Guide grooves for steel balls were processed using a wire EDM (Electrical Discharge Machining) after the heat treatment. With such a design of the guide post stated above, loads against steel balls could be dispersed greatly by the line contacts through the guide groove between the guide pin and the guide bush, and the life span of the guide post could be expanded semi-permanently.

Kim, Gun-hoi; So, Jung D.; Kwon, Kyu-sik; Byun, Jong-won

2007-12-01

246

Egyptian Caste System  

NSDL National Science Digital Library

Understand the culture, character, and societal characteristics of different classes in the ancient Egyptian caste system Understand the culture, character, and societal characteristics of different classes in the ancient Egyptian caste system Go to these sites to learn about the Egyptian Caste System ...

Ms. Issen

2009-09-17

247

Casting and Molding  

NSDL National Science Digital Library

This activity was designed for blind learners, but all types of learners can explore the process used to cast and mold molten metal, glass, and plastics. Using gelatin, the learner will work with a variety of molds to create castings. When the shapes are unmolded, the learner can tactually explore the casts.

Perkins School for the Blind

2012-06-26

248

Bekommt die Erde Fieber?  

E-print Network

Bekommt die Erde Fieber? Y Warum zwei Grad mehr die Grenze sind Y Was ETH-Forscher gegen den gegen Klimawandel. 8 Grosseinsatz der Klimaforschung Wie ETH-Klimaforscher bei der Erde Fieber messen und was zwei Grad mehr für die Erde und die Schweiz bedeuten. 14 Fakten gegen Meinungen

Daraio, Chiara

249

Die Missionsziele Die Erde ist einem stndigen Beschuss mit energiereichen  

E-print Network

Die Missionsziele Die Erde ist einem ständigen Beschuss mit energiereichen Teilchen von der Sonne Magnetosphäre der Erde, die durch die ständige Wechselwirkung unseres Magnetfeldes mit dem Sonnenwind elektrisch leitendes Salzwasser über die Erd- oberfläche bewegen, erzeugen ebenfalls ein schwaches Magnetfeld

Sandoghdar, Vahid

250

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

SciTech Connect

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.

Baldwin, M.D. [Sandia National Labs., Albuquerque, NM (United States); Hochanadel, P.W. [Colorado School of Mines, Golden, CO (United States). Dept. of Metallurgical and Materials Engineering

1995-11-01

251

Methods and apparatus for manufacturing monocrystalline cast silicon and monocrystalline cast silicon bodies for photovoltaics  

SciTech Connect

Methods and apparatuses are provided for casting silicon for photovoltaic cells and other applications. With such methods and apparatuses, a cast body of monocrystalline silicon may be formed that is free of, or substantially free of, radially-distributed impurities and defects and having at least two dimensions that are each at least about 35 cm is provided.

Stoddard, Nathan G

2014-01-14

252

Methods and apparatuses for manufacturing monocrystalline cast silicon and monocrystalline cast silicon bodies for photovoltaics  

DOEpatents

Methods and apparatuses are provided for casting silicon for photovoltaic cells and other applications. With such methods and apparatuses, a cast body of monocrystalline silicon may be formed that is free of, or substantially free of, radially-distributed impurities and defects and having at least two dimensions that are each at least about 35 cm is provided.

Stoddard, Nathan G. (Gettysburg, PA)

2011-11-01

253

Die drool and die drool theory  

NASA Astrophysics Data System (ADS)

When molten plastic is extruded from a die, it sometimes collects on the open face of the die. Known as die drool, this phenomenon costs plastics manufacturers by requiring die cleaning. This has been attributed to many causes, but none of these has led to an equation for the drool rate. In this work we provide an exact analytical solution for the drool rate, and we base this solution on a postulate of a cohesive slip layer near the die walls. We thus attribute die drool to cohesive failure within the fluid at an internal surface where the fluid slips on itself. We adimensionalize the drool rate with the production rate, and call this the build up ratio, BR. We provide an exact analytical solution for BR when the cohesive slip layer either sticks at the wall. We examine the slit geometry corresponding to sheet or film extrusion.

Schmalzer, A. M.; Giacomin, A. Jeffrey

2013-04-01

254

Processing of IN-718 Lattice Block Castings  

NASA Technical Reports Server (NTRS)

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.

Hebsur, Mohan G.

2002-01-01

255

Effect of the casting process on microstructure and lifetime of the Al-piston-alloy AlSi12Cu4Ni3 under thermo-mechanical fatigue with superimposed high-cycle fatigue loading  

Microsoft Academic Search

For the present research work, the well-known Al-piston-alloy AlSi12Cu4Ni3 was manufactured in three different processes (gravity die casting – GDC, low pressure die casting – LPDC, and high pressure die casting – HPDC) and T5 heat treated. The microstructure of the material from each process was analyzed, specimens were tested in OP-TMF loading with and without superimposed high-frequency fatigue and

Alexander Humbertjean; Tilmann Beck

256

Application of the ToxMiner Database: Network Analysis of Linkage between ToxCast Phase I Chemicals and Thyroid Related Disease Outcomes  

EPA Science Inventory

The US EPA ToxCast program is using in vitro HTS (High-Throughput Screening) methods to profile and model bioactivity of environmental chemicals. The main goals of the ToxCast program are to generate predictive signatures of toxicity, and ultimately provide rapid and cost-effecti...

257

Application of the ToxMiner Database: Network Analysis Linking the ToxCast Chemicals to Known Disease-Gene Associations  

EPA Science Inventory

The US EPA ToxCast program is using in vitro HTS (High-Throughput Screening) methods to profile and model bioactivity of environmental chemicals. The main goals of the ToxCast program are to generate predictive signatures of toxicity, and ultimately provide rapid and cost-effecti...

258

[Fluidity of casting materials in plane spreading].  

PubMed

The high fluid elastomer materials for making casts used for the double impression technique were studied with the so-called disc test in terms of their fluidity, diffusion, and layer thickness. The pressure exerted was also recorded at the same time. Our study showed that the low viscosity of the cast material and the application of small amounts were the prerequisites for obtaining the thinnest layer possible. PMID:292586

Rehberg, H J

1979-09-01

259

Packaged die heater  

DOEpatents

A heater for heating packaged die for burn-in and heat testing is described. The heater may be a ceramic-type heater with a metal filament. The heater may be incorporated into the integrated circuit package as an additional ceramic layer of the package, or may be an external heater placed in contact with the package to heat the die. Many different types of integrated circuit packages may be accommodated. The method provides increased energy efficiency for heating the die while reducing temperature stresses on testing equipment. The method allows the use of multiple heaters to heat die to different temperatures. Faulty die may be heated to weaken die attach material to facilitate removal of the die. The heater filament or a separate temperature thermistor located in the package may be used to accurately measure die temperature.

Spielberger, Richard; Ohme, Bruce Walker; Jensen, Ronald J.

2011-06-21

260

Displaced capillary dies  

DOEpatents

An asymmetrical shaped capillary die made exclusively of graphite is used to grow silicon ribbon which is capable of being made into solar cells that are more efficient than cells produced from ribbon made using a symmetrically shaped die.

Kalejs, Juris P. (Wellesley, MA); Chalmers, Bruce (Falmouth, MA); Surek, Thomas (Englewood, CO)

1982-01-01

261

Displaced capillary dies  

DOEpatents

An asymmetrical shaped capillary die made exclusively of graphite is used to grow silicon ribbon which is capable of being made into solar cells that are more efficient than cells produced from ribbon made using a symmetrically shaped die.

Kalejs, Juris P. (Wellesley, MA); Chalmers, Bruce (Falmouth, MA); Surek, Thomas (Englewood, CO)

1984-01-01

262

Cast Metals Coalition Technology Transfer and Program Management Final Report  

SciTech Connect

The Cast Metals Coalition (CMC) partnership program was funded to ensure that the results of the Department of Energy's (DOE) metalcasting research and development (R&D) projects are successfully deployed into industry. Specifically, the CMC program coordinated the transfer and deployment of energy saving technologies and process improvements developed under separately funded DOE programs and projects into industry. The transition of these technologies and process improvements is a critical step in the path to realizing actual energy savings. At full deployment, DOE funded metalcasting R&D results are projected to save 55% of the energy used by the industry in 1998. This closely aligns with DOE's current goal of driving a 25% reduction in industrial energy intensity by 2017. In addition to benefiting DOE, these energy savings provide metalcasters with a significant economic advantage. Deployment of already completed R&D project results and those still underway is estimated to return over 500% of the original DOE and industry investment. Energy savings estimates through December 2008 from the Energy-Saving Melting and Revert Reduction Technology (E-SMARRT) portfolio of projects alone are 12 x 1012 BTUs, with a projection of over 50 x 1012 BTUs ten years after program completion. These energy savings and process improvements have been made possible through the unique collaborative structure of the CMC partnership. The CMC team consists of DOE's Office of Industrial Technology, the three leading metalcasting technical societies in the U.S: the American Foundry Society; the North American Die Casting Association; and the Steel Founders Society of America; and the Advanced Technology Institute (ATI), a recognized leader in distributed technology management. CMC provides collaborative leadership to a complex industry composed of approximately 2,100 companies, 80% of which employ less than 100 people, and only 4% of which employ more than 250 people. Without collaboration, new technologies enabling energy efficiencies and environment-friendly improvements are slow to develop, and have trouble obtaining a broad application. The CMC team was able to effectively and efficiently transfer the results of DOE's metalcasting R&D projects to industry by utilizing and delivering the numerous communication vehicles identified in the proposal. The three metalcasting technical associations achieved significant technology transition results under this program. In addition to reaching over 23,000 people per year through Modern Casting and 28,000 through Engineered Casting Solutions, AFS had 84 national publications and reached over 1,200 people annually through Cast Metals Institute (CMI) education courses. NADCA's education department reached over 1,000 people each year through their courses, in addition to reaching over 6,000 people annually through Die Casting Engineer, and publishing 58 papers. The SFSA also published 99 research papers and reached over 1,000 people annually through their member newsletters. In addition to these communication vehicles, the CMC team conducted numerous technical committee meetings, project reviews, and onsite visits. All of these efforts to distribute the latest metalcasting technologies contributed to the successful deployment of DOE's R&D projects into industry. The DOE/CMC partnership demonstrated significant success in the identification and review of relevant and easy-to-implement metalcasting energy-saving processes and technologies so that the results are quickly implemented and become general practice. The results achieved in this program demonstrate that sustained technology transfer efforts are a critical step in the deployment of R&D projects to industry.

Gwyn, Mike

2009-03-31

263

Evolution of halictine castes  

NASA Astrophysics Data System (ADS)

Social halictine bees have female castes that range from species with no size differences to those with a discrete bimodality. Female caste differences are inversely correlated with the number of males produced in the first brood. It is proposed that the sexual dimorphism of solitary forms is being usurped by the female caste system of species in the process of turning social. Thus, caste differences and summer male suppression are greatest in the social species originating from solitary precursors with distinct sexual dimorphism, and are least in species evolving from solitary ancestors with a continuous sexual polymorphism.

Knerer, Gerd

1980-03-01

264

Die Coin Experiment  

NSDL National Science Digital Library

This resource consists of a Java applet and expository text. The applet simulates the experiment of rolling a die and then tossing a coin the number of times shown on the die. The die distribution and the probability of heads can be specified. The applet illustrates a two-stage experiment.

Kyle Siegrist

265

Es lebe die Unverfrorenheit !\\  

Microsoft Academic Search

uber seine physikalische Interpr etation einer harmlos aus- sehenden, von ihn selbst zuvor aufgestellten Formel, die das spektrale Verhalten der sogenannten Warmestrahlung beschreibt. Maßgeblich durch das Eingreifen Albert Einsteins entwickelte sich daraus im folgenden Vierteljahrhundert eine fundamentale Krise der Physik, die dann in einer wissenschaftlichen Revolution großten Ausmaßes mundete: der Quantentheorie. Die Quantentheorie entwickelte sich von Anfang an diametral gegen

Domenico Giulini

266

Metallic Fuel Casting Development and Parameter Optimization Simulations  

SciTech Connect

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.

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

2013-03-01

267

INTERIOR VIEW WITH PIPE CASTING MACHINE CASTING A 24' PIPE ...  

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

INTERIOR VIEW WITH PIPE CASTING MACHINE CASTING A 24' PIPE AND OPERATOR JOHNNY NIXON. - United States Pipe & Foundry Company Plant, Pipe Casting & Testing Area, 2023 St. Louis Avenue at I-20/59, Bessemer, Jefferson County, AL

268

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. - United States Pipe & Foundry Company Plant, Pipe Casting & Testing Area, 2023 St. Louis Avenue at I-20/59, Bessemer, Jefferson County, AL

269

NWIS MEASUREMENTS FOR URANIUM METAL ANNULAR CASTINGS  

SciTech Connect

This report describes measurements performed with annular uranium metal castings of different enrichments to investigate the use of {sup 252}Cf-source-driven noise analysis measurements as a means to quantify the amount of special nuclear material (SNM) in the casting. This work in FY 97 was sponsored by the Oak Ridge Y-12 Plant and the DOE Office of Technology Development Programs. Previous measurements and calculational studies have shown that many of the signatures obtained from the source-driven measurement are very sensitive to fissile mass. Measurements were performed to assess the applicability of this method to standard annular uranium metal castings at the Oak Ridge Y-12 plant under verification by the International Atomic Energy Agency (IAEA) using the Nuclear Weapons Identification System (NWIS) processor. Before the measurements with different enrichments, a limited study of source-detector-casting moderator configurations was performed to enhance the correlated information. These configurations consisted of a casting with no reflector and with various thicknesses of polyethylene reflectors up to 10.16 cm in 2.54 cm steps. The polyethylene moderator thickness of 7.62 cm was used for measurements with castings of different enrichments reported here. The sensitivity of the measured parameters to fissile mass was investigated using four castings each with a different enrichment. The high sensitivity of this measurement method to fissile mass and to other material and configurations provides some advantages over existing safeguards methods.

MATTINGLY, J.K.; VALENTINE, T.E.; MIHALCZO, J.T.

1998-03-13

270

Duplex-PACVD coating of surfaces for die casting tools  

Microsoft Academic Search

Duplex-PACVD hard coatings are well known for increasing the tool performance in terms of adhesion, wear, fatigue, and corrosion resistance of the steel. The developments made in synthesizing duplex nanostructure and nanocomposite, mono and gradient layers based on borides are described. The aim of the investigation is to optimize the surface capability by plasma process combinations: duplex process and gradient

K. S. Klimek; A. Gebauer-Teichmann; P. Kaestner; K.-T. Rie

2007-01-01

271

Die Fenster zum Himmel  

NASA Astrophysics Data System (ADS)

Mittlerweile steht in Form von Adaptiven Optiken und Interferometern die nötige Technik zur Verfügung, um den Himmel im nahen und mittleren Infrarot mit hoher räumlicher Auflösung zu beobachten. Dadurch können in Sternentstehungsgebieten nicht nur junge Sterne und ihre oftmals vorhandenen Begleiter identifiziert, sondern auch die die jungen Sterne umgebenden Scheiben charakterisiert werden. Diese Scheiben sind von besonderem Interesse, da sie das Material bereitstellen aus dem sich die Sterne, aber potentiell auch Planeten formen. Hier soll gezeigt werden, auf welchen Prinzipien die hochauflösenden Beobachtungstechniken beruhen und wie sie zu einem besseren Verständnis der Sternentstehung beitragen. Es soll aber auch veranschaulicht werden, wie sich unser Blick ins Universum in den letzten Jahrhunderten dramatisch verändert hat.

Ratzka, Thorsten

2012-10-01

272

Japanese R&D on new cast alloys and materials  

SciTech Connect

On the basis of observations of the JTEC team, it appears that Japanese universities and research institutes are leading long-term R&D thrusts for development of new materials casting technologies. Significant efforts include amorphous metals, intermetallics, application of MHD in continuous casting of steel, and energy efficient furnace technology. Industrial R&D seems focused more on process improvements than on new product technologies, but significant efforts in new cast materials included cast metal matrix composites, materials substitutions for thinner wall products, and advanced ceramic products for foundry industry applications.

Hayden, H.W.

1996-05-01

273

The application of floating dies for high speed growth of CsI single crystals by edge-defined film-fed growth (EFG)  

NASA Astrophysics Data System (ADS)

Floating graphite and fused silica dies were used to grow both undoped and Na doped CsI crystals by the edge-defined film-fed growth (EFG) method. Both die materials yielded high quality CsI crystals at high growth rates. Under the conditions employed in these growth experiments, a pull rate of up to 45 mm/h was possible using a 15 mm diameter graphite die. Growth procedures were developed to enhance crystal quality through iterative die design in combination with numerical modeling. The formation of cylindrical voids (bubble tracks) was investigated and methods were developed for their suppression.

Guguschev, Christo; Calvert, George; Podowitz, Stephen; Vailionis, Arturas; Yeckel, Andrew; Feigelson, Robert S.

2014-10-01

274

Cool Cast Facts  

MedlinePLUS

... A splint can be made from the same materials as a cast or may be a pre-made piece of stiff plastic or metal surrounded by strong fabric. It is like a half cast that's wrapped with an elastic bandage or held in place with Velcro straps. A ...

275

Casting the Die before the Die Is Cast: The Importance of the Home Numeracy Environment for Preschool Children  

ERIC Educational Resources Information Center

Mathematical competencies are important not only for academic achievement at school but also for professional success later in life. Although we know a lot about the impact of "Home Literacy Environment" on the development of early linguistic competencies, research on "Home Numeracy Environment" (HNE) and the assessment of its…

Niklas, Frank; Schneider, Wolfgang

2014-01-01

276

Application of Rapid Prototyping to the Investment Casting of Test Hardware (MSFC Center Director's Discretionary Fund Final Report, Project No. 98-08)  

NASA Technical Reports Server (NTRS)

Investment casting masters of a selected propulsion hardware component, a fuel pump housing, were rapid prototyped on the several processes in-house, along with the new Z-Corp process acquired through this project. Also, tensile samples were prototyped and cast using the same significant parameters. The models were then shelled in-house using a commercial grade zircon-based slurry and stucco technique. Next, the shelled models were fired and cast by our in-house foundry contractor (IITRI), with NASA-23, a commonly used test hardware metal. The cast models are compared by their surface finish and overall appearance (i.e., the occurrence of pitting, warping, etc.), as well as dimensional accuracy.

Cooper, K. G.; Wells, D.

2000-01-01

277

Using cold-crucible melting for titanium precision castings  

NASA Astrophysics Data System (ADS)

Titanium precision castings have not kept pace with technical design requirements for demanding applications, such as the aerospace industry; advances in increased size capability have been offset by a lack of advances in metallurgical integrity and dimensional tolerances. Hence, there is a strong need for improvement in the casting process. Taramm has developed a process that combines cold-crucible induction melting and centrifugal pouring to produce viable castings.

Broihanne, Georges; Bannister, John

2000-05-01

278

The twin-roll casting of magnesium alloys  

NASA Astrophysics Data System (ADS)

Recently, technologies for twin-roll casting have been widely developed to efficiently fabricate the lightweight Mg alloy sheets that are quite attractive for numerous weight-sensitive applications. This paper reviews the recent progress in the twin-roll casting of Mg alloys, focusing on the processing aspects that have close relations to the solidification behavior of Mg alloy strips. In addition, recent attempts to develop new Mg alloys utilizing the metallurgical advantages attainable by this novel casting process are also presented.

Park, S. S.; Park, W.-J.; Kim, C. H.; You, B. S.; Kim, Nack J.

2009-08-01

279

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

280

Mechanisms of stabilization of earthworm casts and artificial casts  

Microsoft Academic Search

Fresh casts were collected from the earthworm species Aporrectodea caliginosa, and artificial casts were also made. The casts were subjected to ageing, drying-rewetting, and sterilization by hexanol vapour. Clay dispersion was determined, as a measure of the lack of stability of the casts. Two soils were used, the topsoil of a recently reclaimed polder soil in the Netherlands and the

J. C. Y. Marinissen; A. R. Dexter

1990-01-01

281

Die singulation method  

DOEpatents

A method is disclosed for singulating die from a semiconductor substrate (e.g. a semiconductor-on-insulator substrate or a bulk silicon substrate) containing an oxide layer (e.g. silicon dioxide or a silicate glass) and one or more semiconductor layers (e.g. monocrystalline or polycrystalline silicon) located above the oxide layer. The method etches trenches through the substrate and through each semiconductor layer about the die being singulated, with the trenches being offset from each other around at least a part of the die so that the oxide layer between the trenches holds the substrate and die together. The trenches can be anisotropically etched using a Deep Reactive Ion Etching (DRIE) process. After the trenches are etched, the oxide layer between the trenches can be etched away with an HF etchant to singulate the die. A release fixture can be located near one side of the substrate to receive the singulated die.

Swiler, Thomas P.; Garcia, Ernest J.; Francis, Kathryn M.

2013-06-11

282

Die singulation method  

DOEpatents

A method is disclosed for singulating die from a semiconductor substrate (e.g. a semiconductor-on-insulator substrate or a bulk silicon substrate) containing an oxide layer (e.g. silicon dioxide or a silicate glass) and one or more semiconductor layers (e.g. monocrystalline or polycrystalline silicon) located above the oxide layer. The method etches trenches through the substrate and through each semiconductor layer about the die being singulated, with the trenches being offset from each other around at least a part of the die so that the oxide layer between the trenches holds the substrate and die together. The trenches can be anisotropically etched using a Deep Reactive Ion Etching (DRIE) process. After the trenches are etched, the oxide layer between the trenches can be etched away with a HF etchant to singulate the die. A release fixture can be located near one side of the substrate to receive the singulated die.

Swiler, Thomas P [Albuquerque, NM; Garcia, Ernest J [Albuquerque, NM; Francis, Kathryn M [Rio Rancho, NM

2014-01-07

283

Extrusion die and method  

DOEpatents

A method and die apparatus for manufacturing a honeycomb body of rhombic cell cross-section by extrusion through an extrusion die of triangular cell discharge slot configuration, the die incorporating feedholes at selected slot intersections only, such that slot segments communicating directly with the feedholes discharge web material and slot segments not so connected do not discharge web material, whereby a rhombic cell cross-section in the extruded body is provided.

Lipp, G. Daniel (Painted Post, NY)

1994-04-26

284

Slip casting of partially stabilized zirconia  

SciTech Connect

The toughness of partially-stabilized zirconia has been studied for some time. The tetragonal phase in partially stabilized ZrO2 transforms to the monoclinic phase under the influence of stress. Partially-stabilized ZrO2 has enhanced tensile strength, good wear resistance and low friction coefficient, and has found industrial applications. This article describes the use of partially-stabilized zirconia in slip casting. Lab techniques of slip casting have been reported for nonplastic materials such as Al2O3, CaF2, CaO-stabilized ZrO2 and MgO. The article discusses the variation of slip density and firing temperature and also reports the preparation of specimens of CaOstabilized ZrO2 by slip casting from ethanol-based suspensions. The preparation of Y2O3-ZrO2 compositions by slip casting from aqueous suspension is also reported. A Y2O3 partially stabilized ZrO2 powder was used as a starting material. The densities of the cast specimens were measured from the volume and weight, and those of the sintered specimens were measured by a liquid displacement technique using distilled water. The concentation of the suspension strongly affects the relative density of the cast specimen and the firing shrinkage of the sintered specimen, while the relative density of the sintered specimen is independent of the concentration of the suspension.

Taguchi, H.; Miyamoto, H.; Takahashi, Y.

1985-02-01

285

Silica exposure in hand grinding steel castings.  

PubMed

Exposure to silica dust was studied in the grinding of castings in a steel foundry that used conventional personal sampling methods and new real-time sampling techniques developed for the identification of high-exposure tasks and tools. Approximately one-third of the personal samples exceeded the National Institute for Occupational Safety and Health recommended exposure limit for crystalline silica, a fraction similar to that identified in other studies of casting cleaning. Of five tools used to clean the castings, the tools with the largest wheels, a 6-in. grinder and a 4-in. cutoff wheel, were shown to be the major sources of dust exposure. Existing dust control consisted of the use of downdraft grinding benches. The size of the casting precluded working at a distance close enough to the grates of the downdraft benches for efficient capture of the grinding dust. In addition, measurements of air recirculated from the downdraft benches indicated that less than one-half of the respirable particles were removed from the contaminated airstream. Previous studies have shown that silica exposures in the cleaning of castings can be reduced or eliminated through the use of mold coatings, which minimize sand burn-in on the casting surface; by application of high-velocity, low-volume exhaust hoods; and by the use of a nonsilica molding aggregate such as olivine. This study concluded that all these methods would be appropriate control options. PMID:1317091

O'Brien, D; Froehlich, P A; Gressel, M G; Hall, R M; Clark, N J; Bost, P; Fischbach, T

1992-01-01

286

Application of in situ thermography for evaluating the high-cycle and very high-cycle fatigue behaviour of cast aluminium alloy AlSi7Mg (T6).  

PubMed

The present paper illustrates the application of infrared thermal measurements for the investigation of crack initiation point and crack propagation in the high-cycle and the very high-cycle fatigue range of cast AlSi7Mg alloy (A356). The influence of casting defects, their location, size and amount was studied both by fractography and thermography. Besides internal and surface fatigue crack initiation as a further crack initiation type multiple fatigue crack initiation was observed via in situ thermography which can be well correlated with the results from fractography obtained by SEM investigations. In addition, crack propagation was studied by the development of the temperature measured via thermography. Moreover, the frequency influence on high-cycle fatigue behaviour was investigated. The presented results demonstrate well that the combination of fractography and thermography can give a significant contribution to the knowledge of crack initiation and propagation in the VHCF regime. PMID:23541962

Krewerth, D; Weidner, A; Biermann, H

2013-12-01

287

A Comparison of Creep-Rupture Tested Cast Alloys HR282, IN740 and 263 for Possible Application in Advanced Ultrasupercritical Steam Turbine and Boiler  

SciTech Connect

Cast forms of traditionally wrought Ni-base precipitation-strengthened superalloys are being considered for service in the ultra-supercritical conditions (760°C, 35MPa) of next-generation steam boilers and turbines. After casting and homogenization, these alloys were given heat-treatments typical for each in the wrought condition to develop the gamma-prime phase. Specimens machined from castings were creep-rupture tested in air at 800°C. In their wrought forms, alloy 282 is expected to precipitate M23C6 within grain boundaries, alloy 740 is expected to precipitate several grain boundary phases including M23C6, G Phase, and ? phase, and alloy 263 has M23C6 and MC within its grain boundaries. This presentation will correlate the observed creep-life of these cast alloys with the microstructures developed during creep-rupture tests, with an emphasis on the phase identification and chemistry of precipitated grain boundary phases. The suitability of these cast forms of traditionally wrought alloys for turbine and boiler components will also be discussed.

Jablonski, P D; Evens, N; Yamamoto, Y; Maziasz, P

2011-02-27

288

Viability changes: Microbiological analysis of dental casts  

PubMed Central

Background This study evaluated the survival of the most prevalent oral bacteria and fungi (Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, and Candida albicans) in dental casts, and compared changes in the amounts of these microorganisms at different time intervals to determine how long dental casts may pose threat to the health of dental personnel and patients. Material/Methods When manufacturing the casts, regular water was replaced with sterile distilled water, where suspensions of the studied bacteria or the fungus at certain concentrations were prepared. When the dental casts were fully set (solidified), plaster shavings were examined immediately after the contact of the studied microorganism with the plaster, as well as after 1, 2, 24, 48, 72, 96, and 120 hours. Following that, we measured how the amount of the studied bacteria and fungi in 1 gram of the plaster changed within the studied period of time. Results Klebsiella pneumoniae survived in plaster for up to 4 days, and the reduction in the number of these bacteria became statistically significant after 1 day (p<0.05). Staphylococcus aureus remained viable in plaster for up to 4 days, and the number of these bacteria dropped after 1 day (p<0.05). Escherichia coli disappeared after 2 days, and a reduction was already observed after 2 hours (p<0.05). Candida albicans in plaster models died within 2 days, and a reduction in their number was observed after 1 day (p<0.05). Conclusions The microorganisms did not multiply in the gypsum casts and their number significantly dropped instead of increasing. PMID:24902637

Žilinskas, Juozas; Junevi?ius, Jonas; Ramonait?, Agn?; Pavilonis, Alvydas; Gleiznys, Alvydas; Sakalauskien?, Jurgina

2014-01-01

289

[Evaluation of cervical discrepancy of gold crowns in stone dies from various impression materials].  

PubMed

A stainless steel master die simulating a dental preparation for crown was used to make 3 gold castings from wax patterns obtained in 3 different ways: a) directly from the naked master die; b) from the same master die with a copper coping 30 microns thick; and c) with a similar copper coping, but 40 microns thick. The discrepancies of fit of the 3 master gold crowns were evaluated in 99 stones dies (33 for each casting) obtained from 11 different elastomeric impression materials (3 replicae of each). The results showed that: 1) stone dies with no coping presented a medium discrepancy of 284 microns, inadequate for clinical use; 2) the 30 microns and 40 microns copings presented medium discrepancies of 18 and 9 microns respectively, both suitable for clinical use. Thus, the use of copings tend to equalize the cervical discrepancy of fit of gold crowns, whatever be the elastomeric impression material used. PMID:2135328

Mantovani, A V; Stephano, C B; Roselino, R F; Roselino, R B; Campos, G M

1990-01-01

290

Method of casting aerogels  

DOEpatents

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.

Poco, J.F.

1993-09-07

291

Method of casting aerogels  

DOEpatents

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.

Poco, John F. (Livermore, CA)

1993-01-01

292

Control design and implementation in continuous steel casting  

Microsoft Academic Search

Accurate control of the mold level in continuous casting is believed to be a key factor in improving the quality of the cast product. This paper describes an application of advanced control to this problem leading to a complete recommissioning of the mold level control system. Careful physical modeling identified smooth as well as nonsmooth nonlinearities in the process. Three

S. F. Graebe; G. C. Goodwin; G. Elsley

1995-01-01

293

Automatic 3D modeling of palatal plaster casts Marco Andreetto  

E-print Network

duplicated by 3D printers. A second application where 3D models of palatal casts could also be usefulAutomatic 3D modeling of palatal plaster casts Marco Andreetto Dept. of Information Engineer corte@dei.unipd.it Abstract This work introduces a procedure for automatic 3D model- ing and discusses

Abu-Mostafa, Yaser S.

294

MicroCast: Cooperative Video Streaming on Smartphones Lorenzo Keller  

E-print Network

MicroCast: Cooperative Video Streaming on Smartphones Lorenzo Keller School of I&C EPFL, Lausanne, applications on smartphones today. In this paper, we con- sider a group of smartphone users, within proximityCast, that uses the resources on all smartphones of the group in a co- operative way so as to improve

Markopoulou, Athina

295

Salvaged castings and methods of salvaging castings with defective cast cooling bumps  

DOEpatents

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.

Johnson, Robert Alan (Simpsonville, SC); Schaeffer, Jon Conrad (Greenville, SC); Lee, Ching-Pang (Cincinnati, OH); Abuaf, Nesim (Lincoln City, OR); Hasz, Wayne Charles (Pownal, VT)

2002-01-01

296

Burnishability of a nickel and a cobalt base casting alloys.  

PubMed

A specially designed stainless steel split die capable of producing a total of 24 half cylindrical shaped wax patterns was used in this study. The burnishability of two non-precious casting alloys was evaluated following a proposed softening heat treatment technique. A practical easily applied burnishing tool was introduced. Results have shown that, both of the non-precious alloys were burnishable following softening heat treatment. However, nickel-chromium alloy was significantly more burnishable than the cobalt-chromium alloy. It is suggested that clinical implications of the developed technique in this study would be an important additive for more precision castings. PMID:2701428

Nasr, H H; Mosleh, I

1989-10-01

297

A method for determining adequate resistance form of complete cast crown preparations.  

PubMed

A diagram with various degrees of occlusal convergence, which takes into consideration the length and diameter of complete crown preparations, was designed as a guide to assist the dentist to obtain adequate resistance form. To test the validity of the diagram, five groups of complete cast crown stainless steel dies were prepared (3.5 mm long, occlusal convergence 10, 13, 16, 19, and 22 degrees). Gold copings were cast for each of the 50 preparations. Displacement force was applied to the casting perpendicularly to a simulated 30-degree cuspal incline until the casting was displaced. Castings were deformed at margins except for the 22-degree group. Castings from this group were displaced without deformation, and it was concluded that there was a lack of adequate resistance form as predicted by the diagram. The hypothesis that the diagram could be used to predict adequate or inadequate resistance form was confirmed by this study. PMID:6384470

Weed, R M; Baez, R J

1984-09-01

298

Die Anwendung des Logit Modells auf die Daten der  

E-print Network

. . . . . . . . . . . . . . . . . . . . . . . . . . 4 4.1 Space Shuttle: Orbiter, externer Brennstofftank, Raketentriebwerke, Field JointsDie Anwendung des Logit Modells auf die Daten der Challenger-Katastrophe Bachelorarbeit Stefanie 15 4.1 Technische Aspekte der Challenger . . . . . . . . . . . . . . . . . . . . . . . 15 4.2 Die

299

Adapt or die?  

PubMed

The worldwide economic recession and the concomitant limited stock of finances have had an influence on the available money of every household and have also inhibited the improvement of socio-economic conditions and medicine. The Reconstruction and Development Programme (RDP) has the objective of improving the living conditions of the people with regard to housing, education, training and health care. The latter seems to be a major problem which has to be addressed with the emphasis on the preventive and promotional aspects of health care. A comprehensive health care system did not come into being property in the past because of the maldistribution of health care services, personnel and differences in culture and health care beliefs and values. The question that now arises, is how to render a quality health care service within the constraints of inadequate financing and resources. A comprehensive literature study has been done with reference to quality health care and financing followed by a survey of existing health services and finances. Recommendations are made about minimum requirements to be accepted if one were to adapt rather than die in terms of the provision of healthcare: the decentralization and rationalization of the administration of health care, the stress on and realization of effective and efficient primary health care, the acceptance of participative management in health providing organizations, the provision of financial management training for health care managers and the application of management accounting principles for the improvement of the efficiency and effectiveness of management. PMID:9283343

Visser, S S; Nel, A H

1996-12-01

300

Spray casting project final report  

SciTech Connect

Lockheed Martin Energy Systems, Inc. (Energy Systems), along with other participating organizations, has been exploring the feasibility of spray casting depleted uranium (DU) to near-net shape as a waste minimization effort. Although this technology would be useful in a variety of applications where DU was the material of choice, this effort was aimed primarily at gamma-shielding components for use in storage and transportation canisters for high-level radioactive waste, particularly in the Multipurpose Canister (MPC) application. In addition to the waste-minimization benefits, spray casting would simplify the manufacturing process by allowing the shielding components for MPC to be produced as a single component, as opposed to multiple components with many fabrication and assembly steps. In earlier experiments, surrogate materials were used to simulate the properties (specifically reactivity and density) of DU. Based on the positive results from those studies, the project participants decided that further evaluation of the issues and concerns that would accompany spraying DU was warranted. That evaluation occupied substantially all of Fiscal Year 1995, yielding conceptual designs for both an intermediate facility and a production facility and their associated engineering estimates. An intermediate facility was included in this study to allow further technology development in spraying DU. Although spraying DU to near-net shape seems to be feasible, a number of technical, engineering, and safety issues would need to be evaluated before proceeding with a production facility. This report is intended to document the results from the spray-casting project and to provide information needed by anyone interested in proceeding to the next step.

Churnetski, S.R.; Thompson, J.E.

1996-08-01

301

Cast shadow segmentation using invariant color features  

Microsoft Academic Search

Shadows are integral parts of natural scenes and one of the elements contributing to nat- uralness of synthetic scenes. In many image analysis and interpretation applications, shadows interfere with fundamental tasks such as object extraction and description. For this reason, shadow segmentation is an important step in image analysis. In this paper, we propose a new cast shadow segmentation algorithm

Elena Salvador; Andrea Cavallaro; Touradj Ebrahimi

2004-01-01

302

Tox21 and ToxCast Chemical Landscapes: Laying the Foundation for 21st Century Toxicology - Application of the Strategy to Chemical Testing  

EPA Science Inventory

The U.S. Environmental Protection Agency?s ToxCast project and the related, multi-Agency Tox21 project are employing high-throughput technologies to screen hundreds to thousands of chemicals in hundreds of assays, probing a wide diversity of biological targets, pathways and mecha...

303

Extending the Derek-Meteor Workflow to Predict Chemical-Toxicity Space Impacted by Metabolism: Application to ToxCast and Tox21 Chemical Inventories  

EPA Science Inventory

A central aim of EPA?s ToxCast project is to use in vitro high-throughput screening (HTS) profiles to build predictive models of in vivo toxicity. Where assays lack metabolic capability, such efforts may need to anticipate the role of metabolic activation (or deactivation). A wo...

304

Application of Targeted Functional Assays to Assess a Putative Vascular Disruption Developmental Toxicity Pathway Informed By ToxCast High-Throughput Screening Data  

EPA Science Inventory

Chemical perturbation of vascular development is a putative toxicity pathway which may result in developmental toxicity. EPA?s high-throughput screening (HTS) ToxCast program contains assays which measure cellular signals and biological processes critical for blood vessel develop...

305

Accuracy of one-piece castings, preceramic and postceramic soldering.  

PubMed

An investigation was conducted to evaluate the relative accuracy of one-piece castings of FPDs of three, four, and five units with those assembled by preceramic soldering and postceramic soldering. The preceramic soldered FPDs were subjected to six simulated porcelain firing cycles to assure a homogeneous sample. A total of 15 FPDs, five of each length, were evaluated for each test condition. A three-piece aluminum mold with stainless steel dies, which allowed for varying the length of the prosthesis, was used to fabricate the FPDs in 52% gold-palladium alloy. Marginal discrepancies of the castings on the dies were compared for the three test techniques. The mesiodistal length of the FPDs that were pre- and postsoldered were also measured at the occlusal and at the gingival margins and compared with the restorations before soldering. PMID:2870184

Ziebert, G J; Hurtado, A; Glapa, C; Schiffleger, B E

1986-03-01

306

Die andere Revolution  

NASA Astrophysics Data System (ADS)

War Kopernikus der größte Revolutionär des naturwissenschaftlichen Weltbildes? Seine Erkenntnisse waren der Beginn eines jahrhundertelangen Denkprozesses, welcher zur Einsicht führte, dass im Weltall die gleichen physikalischen Gesetze gelten wie auf der Erde.

Kippenhahn, Rudolf

2005-05-01

307

Über die Alkaptonurie  

Microsoft Academic Search

Es wird der normale und pathologische Stoffwechsel der beiden Aminosäuren Phenylalanin und Tyrosin erörtert, wobei auf die angeborenen Stoffwechselstörungen (Albinismus, Tyrosinosis und Oligophrenia phenylpyruvica neben der Alkaptonurie) kurz eingegangen wird.

Kurt Schreier; Hans Plückthun

1952-01-01

308

Composites for Advanced Space Transportation Systems (CASTS)  

NASA Technical Reports Server (NTRS)

A summary is given of the in-house and contract work accomplished under the CASTS Project. In July 1975 the CASTS Project was initiated to develop graphite fiber/polyimide matrix (GR/PI) composite structures with 589K (600 F) operational capability for application to aerospace vehicles. Major tasks include: (1) screening composites and adhesives, (2) developing fabrication procedures and specifications, (3) developing design allowables test methods and data, and (4) design and test of structural elements and construction of an aft body flap for the Space Shuttle Orbiter Vehicle which will be ground tested. Portions of the information are from ongoing research and must be considered preliminary. The CASTS Project is scheduled to be completed in September 1983.

Davis, J. G., Jr. (compiler)

1979-01-01

309

A new casting defect healing technology  

SciTech Connect

A new technology is presented for healing of defects in 356 aluminium alloys that provides economic upgrading of these cast alloys. It uses pneumatic isostatic forging (PIF) to produce high quality Al alloys products with enhanced mechanical properties uniform throughout the part, allowing higher design allowables and increased usage of Al alloy castings. The fundamental mechanism underlying PIF is a single mode plastic deformation process that uses isostatic application of pressures for 10-30 seconds at temperature. The process can be integrated in-line with other production operations, i.e., using the latent heat from the previous casting step. Results of applying the PIF process indicate lower cost and significant improvement in mechanical properties that rival and often exceed corresponding properties of other technologies like hot isostatic pressing and related processes. This process offers many advantages that are described in this paper in addition to presenting case histories of property enhancement by PIF and the mechanism responsible for property enhancement.

Hodge, E.S.; Reddoch, T.W. [ForMat Industries, Inc., Knoxville, TN (United States); Viswanathan, S. [Oak Ridge National Lab., TN (United States)

1997-01-01

310

TiC reinforced cast chromium steels  

SciTech Connect

A series of new titanium carbide reinforced cast chromium steels were developed for wear applications. Objective of the program was to enhance wear resistant alloys and, if possible, improve mechanical properties. The new steels which were melted in a vacuum induction furnace contained 12 Cr, 3-5 Ti, 1-2 C in weight percent. Alloying with Ti changed the precipitate microstructure from Cr carbide to TiC dispersed in a martensitic matrix. Yield strength and impact resistance improved with Ti alloying. Wear rates of the cast Cr/TiC steels, (determined from high- and low-stress abrasion tests, erosion test, and scratch tests) were generally lower than both the as-cast and heat-treated AISI type 440°C steel and were often further reduced by increasing the Ti alloy concentration. The exceptions were the erosion test for which all materials had similar wear rate.

Dogan, Omer N.; Rawers, James C.; Hawk, Jeffrey A.; Schrems, Karol K.

2003-11-01

311

Coin Die Experiment  

NSDL National Science Digital Library

This resource consists of a Java applet and expository text. The applet is a simulation of the experiment that consists of tossing a coin and then rolling either a red die or a green die, depending on the outcome of the coin toss. The probability of heads and the distributions of the two dice can be specified. The applet illustrates a two-stage experiment.

Kyle Siegrist

312

Hickey, C8206_all casts Hickey, C8206_all casts, page 1  

E-print Network

Hickey, C8206_all casts Hickey, C8206_all casts, page 1 #12;Hickey, C8206_all casts Hickey, C8206_all casts, page 2 #12;Hickey, C8206_all casts Hickey, C8206_all casts, page 3 #12;Hickey, C8206_all casts Hickey, C8206_all casts, page 4 #12;Hickey, C8206_all casts Hickey, C8206_all casts, page 5 #12

Hickey, Barbara

313

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

314

Simulation of Dimensional Changes in Steel Casting  

E-print Network

Simulation of Dimensional Changes in Steel Casting Shouzhu (Hans) Ou and Christoph Beckermann Pattern allowances in casting of steel are predicted using the casting simulation software MAGMASOFT to predict dimensional changes occurring during solidification and cooling of a steel casting

Beckermann, Christoph

315

14 CFR 27.621 - Casting factors.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Casting factors. 27.621 Section 27.621...Construction General § 27.621 Casting factors. (a) General. ...d) of this section apply to structural castings except castings that are pressure...

2012-01-01

316

14 CFR 29.621 - Casting factors.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Casting factors. 29.621 Section 29.621...Construction General § 29.621 Casting factors. (a) General. ...d) of this section apply to structural castings except castings that are pressure...

2013-01-01

317

14 CFR 29.621 - Casting factors.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Casting factors. 29.621 Section 29.621...Construction General § 29.621 Casting factors. (a) General. ...d) of this section apply to structural castings except castings that are pressure...

2011-01-01

318

14 CFR 27.621 - Casting factors.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Casting factors. 27.621 Section 27.621...Construction General § 27.621 Casting factors. (a) General. ...d) of this section apply to structural castings except castings that are pressure...

2013-01-01

319

14 CFR 25.621 - Casting factors.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Casting factors. 25.621 Section 25.621...Construction General § 25.621 Casting factors. (a) General. ...of this section apply to any structural castings except castings that are pressure...

2012-01-01

320

14 CFR 27.621 - Casting factors.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Casting factors. 27.621 Section 27.621...Construction General § 27.621 Casting factors. (a) General. ...d) of this section apply to structural castings except castings that are pressure...

2014-01-01

321

14 CFR 27.621 - Casting factors.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Casting factors. 27.621 Section 27.621...Construction General § 27.621 Casting factors. (a) General. ...d) of this section apply to structural castings except castings that are pressure...

2011-01-01

322

14 CFR 25.621 - Casting factors.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Casting factors. 25.621 Section 25.621...Construction General § 25.621 Casting factors. (a) General. ...of this section apply to any structural castings except castings that are pressure...

2014-01-01

323

14 CFR 27.621 - Casting factors.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Casting factors. 27.621 Section 27.621...Construction General § 27.621 Casting factors. (a) General. ...d) of this section apply to structural castings except castings that are pressure...

2010-01-01

324

14 CFR 29.621 - Casting factors.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Casting factors. 29.621 Section 29.621...Construction General § 29.621 Casting factors. (a) General. ...d) of this section apply to structural castings except castings that are pressure...

2012-01-01

325

14 CFR 29.621 - Casting factors.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Casting factors. 29.621 Section 29.621...Construction General § 29.621 Casting factors. (a) General. ...d) of this section apply to structural castings except castings that are pressure...

2014-01-01

326

14 CFR 25.621 - Casting factors.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Casting factors. 25.621 Section 25.621...Construction General § 25.621 Casting factors. (a) General. ...of this section apply to any structural castings except castings that are pressure...

2011-01-01

327

Method for casting polyethylene pipe  

NASA Technical Reports Server (NTRS)

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.

Elam, R. M., Jr.

1973-01-01

328

Casting Of Multilayer Ceramic Tapes  

NASA Technical Reports Server (NTRS)

Procedure for casting thin, multilayer ceramic membranes, commonly called tapes, involves centrifugal casting at accelerations of 1,800 to 2,000 times normal gravitational acceleration. Layers of tape cast one at a time on top of any previous layer or layers. Each layer cast from slurry of ground ceramic suspended in mixture of solvents, binders, and other components. Used in capacitors, fuel cells, and electrolytic separation of oxygen from air.

Collins, Earl R., Jr.

1991-01-01

329

Application of X-ray microtomography to study the influence of the casting microstructure upon the tensile behaviour of an Al-Si alloy  

NASA Astrophysics Data System (ADS)

In cast aluminium alloys used in the automotive industry the microstructure inherited from the foundry process has a strong influence on the mechanical properties. In the cylinder heads produced by the Lost Foam Casting process, the microstructure consists of hard intermetallic phases and large gas and microshrinkage pores. To study its influence, full field measurements at the microstructure scale were performed during a tensile test performed in situ under X-ray microtomography. Intermetallics were used as a natural speckle pattern. Feasibility of Digital Volume Correlation on this alloy was proved and the accuracy of the measurement was assessed and discussed in light of the small volume fraction of intermetallics and in comparison with the accuracy of Digital Image Correlation performed on optical images at a finer spatial resolution.

Limodin, Nathalie; El Bartali, Ahmed; Wang, Long; Lachambre, Joël; Buffiere, Jean-Yves; Charkaluk, Eric

2014-04-01

330

Replacing London's cast iron mains  

Microsoft Academic Search

This paper discusses the cast iron gas distribution systems that exist in many cities and contains considerable amounts of pipe that vary in age from 20 to 150 years. In many ways, cast iron is an excellent material. It is inherently corrosion resistant, easy to install and cheap. However, it is also brittle and smaller diameter cast iron pipe has

A. Thorne; P. Mathews

1992-01-01

331

Casting and Angling.  

ERIC Educational Resources Information Center

The self-contained packet contains background information, lesson plans, 15 transparency and student handout masters, drills and games, 2 objective examinations, and references for teaching a 15-day unit on casting and angling to junior high and senior high school students, either as part of a regular physical education program or as a club…

Little, Mildred J.; Bunting, Camille

332

Evaluation of an improved centrifugal casting machine.  

PubMed

A Type III gold alloy, a silver-palladium alloy, and a base metal alloy were cast in two different centrifugal casting machines. With the number of complete cast mesh squares as an indicator of castability, the Airspin casting machine produced superior castings with all three alloys. The base metal alloy produced the greatest number of complete squares with both casting machines. PMID:3889295

Donovan, T E; White, L E

1985-05-01

333

A comparative assessment of crystallite size and lattice strain in differently cast A356 aluminium alloy  

NASA Astrophysics Data System (ADS)

In this investigation, A356 aluminium alloy has been prepared by different routes viz. gravity casting, rheo pressure die casting (RPDC) and RPDC with T6 heat treatment. X-ray diffraction studies of these samples have been done in the scanning range of 20 – 90°. X-ray peak broadening analysis has been used to estimate the crystallite size and lattice stain, in all the samples. The sample prepared by RPDC with T6 treatment has comparatively smaller crystallite size and lesser lattice strain than gravity cast and RPDC samples.

Mishra, S. K.; Roy, H.; Lohar, A. K.; Samanta, S. K.; Tiwari, S.; Dutta, K.

2015-02-01

334

Rapid cycle casting of steel  

NASA Astrophysics Data System (ADS)

A rapid cycle casting process for steel via diffusion solidification (SD) is developed. Solidification takes place by carbon redistribution between iron saturated high carbon liquid iron and low carbon preexisting solid iron in a refractory mold. The solidification time is shorter and the economic scaling law is less dependent on the size of the casting than in conventional casting processes. The metallurgical and processing aspects of SD casting are addressed and the necessary parameters are developed to design a rapid cycle casting machine. These process parameters in addition to the metallurgical quality variables are included in an economic feasibility analysis of the SD process.

Apelian, D.; Langford, G.

1981-07-01

335

Effects of preparation relief and flow channels on seating full coverage castings during cementation.  

PubMed

Machined steel dies were used to study the effects of three die modifications on seating full coverage castings during cementation. The die modifications consisted of occlusal channels, occlusal surface relief, and axial channels. Fourteen specimens having one or more forms of die modification were compared with two control specimens having no die modifications. Statistical analysis of the data revealed that the addition of four axial channels to the simulated preparation on the steel die produced a significant reduction in the mean marginal discrepancy during cementation. Occlusal modifications alone failed to produce significant reductions in marginal discrepancies when compared with the control specimens. Occlusal modifications in conjunction with axial channels failed to produce further significant reductions in marginal discrepancies when compared with those reductions observed in specimens having only axial channels. PMID:6348259

Webb, E L; Murray, H V; Holland, G A; Taylor, D F

1983-06-01

336

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

SciTech Connect

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

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

2008-11-21

337

Properties of a hybrid plaster-fibreglass cast  

PubMed Central

Objective To examine the suitability of a plaster-fibreglass hybrid cast for orthopedic applications, comparing them to plaster of Paris (POP) and fibreglass constructs. Method Groups of 10 standardized hybrid, POP and fibreglass casts were studied. An Instron servo-hydraulic system was used to test the casts in 3-point bending and shear. Outcome measures Strength, stiffness, weight, thickness and cost of the 3 types of cast, and shear strength at the interface between the POP and fibreglass in the hybrid casts. Results The hybrid casts were twice as strong as the POP constructs, were stiffer and weighed 14% less but were thicker and cost 2.5 times more. They were almost as strong as and less than half the cost of the fibreglass constructs but were thicker, not as stiff, and weighed 42% more. The shear strength of the POP–fibreglass interface in the hybrid casts was higher than the 3-point bending strength of this construct by a factor of 3. Conclusions Plaster-fibreglass hybrid casts should be considered for orthopedic use on the basis of their strength, stiffness, weight and cost, combined with their acknowledged advantages of good moulding ability and water resistance. PMID:11045095

Charles, Mark N.; Yen, David

2000-01-01

338

AMCC casting development, volume 2  

NASA Technical Reports Server (NTRS)

PCC successfully cast and performed nondestructive testing, FPI and x-ray, on seventeen AMCC castings. Destructive testing, lab analysis and chemical milling, was performed on eleven of the castings and the remaining six castings were shipped to NASA or Aerojet. Two of the six castings shipped, lots 015 and 016, were fully processed per blueprint requirements. PCC has fully developed the gating and processing parameters of this part and feels the part could be implemented into production, after four more castings have been completed to ensure the repeatability of the process. The AMCC casting has been a technically challenging part due to its size, configuration, and alloy type. The height and weight of the wax pattern assembly necessitated the development of a hollow gating system to ensure structural integrity of the shell throughout the investment process. The complexity in the jacket area of the casting required the development of an innovative casting technology that PCC has termed 'TGC' or thermal gradient control. This method of setting up thermal gradients in the casting during solidification represents a significant process improvement for PCC and has been successfully implemented on other programs. The alloy, JBK75, is a relatively new alloy in the investment casting arena and required our engineering staff to learn the gating, processing, and dimensional characteristics of the material.

1995-01-01

339

Hickey, TT136, casts 3-5 Hickey, TT136, casts 3-5, page 1  

E-print Network

Hickey, TT136, casts 3-5 Hickey, TT136, casts 3-5, page 1 CTD003 #12;Hickey, TT136, casts 3-5 Hickey, TT136, casts 3-5, page 2 CTD003 #12;Hickey, TT136, casts 3-5 Hickey, TT136, casts 3-5, page 3 CTD003 #12;Hickey, TT136, casts 3-5 Hickey, TT136, casts 3-5, page 4 CTD003 #12;Hickey, TT136, casts 3

Hickey, Barbara

340

Hickey, TT162, casts 6-7 Hickey, TT162, casts 6-7, page 1  

E-print Network

CTD006 Hickey, TT162, casts 6-7 Hickey, TT162, casts 6-7, page 1 #12;CTD006 Hickey, TT162, casts 6-7 Hickey, TT162, casts 6-7, page 2 #12;CTD006 Hickey, TT162, casts 6-7 Hickey, TT162, casts 6-7, page 3 #12;CTD006 Hickey, TT162, casts 6-7 Hickey, TT162, casts 6-7, page 4 #12;CTD006 Hickey, TT162, casts 6

Hickey, Barbara

341

Hickey, TT136, casts 6-10 Hickey, TT136, casts 6-10, page 1  

E-print Network

Hickey, TT136, casts 6-10 Hickey, TT136, casts 6-10, page 1 CTD006 #12;Hickey, TT136, casts 6-10 Hickey, TT136, casts 6-10, page 2 CTD006 #12;Hickey, TT136, casts 6-10 Hickey, TT136, casts 6-10, page 3 CTD006 #12;Hickey, TT136, casts 6-10 Hickey, TT136, casts 6-10, page 4 CTD006 #12;Hickey, TT136, casts

Hickey, Barbara

342

Hickey, TT162, Casts 2-5 Hickey, TT162, Casts 2-5, page 1  

E-print Network

Hickey, TT162, Casts 2-5 Hickey, TT162, Casts 2-5, page 1 CTD002 #12;Hickey, TT162, Casts 2-5 Hickey, TT162, Casts 2-5, page 2 CTD002 #12;Hickey, TT162, Casts 2-5 Hickey, TT162, Casts 2-5, page 3 CTD002 #12;Hickey, TT162, Casts 2-5 Hickey, TT162, Casts 2-5, page 4 CTD002 #12;Hickey, TT162, Casts 2

Hickey, Barbara

343

Volume MLS ray casting.  

PubMed

The method of Moving Least Squares (MLS) is a popular framework for reconstructing continuous functions from scattered data due to its rich mathematical properties and well-understood theoretical foundations. This paper applies MLS to volume rendering, providing a unified mathematical framework for ray casting of scalar data stored over regular as well as irregular grids. We use the MLS reconstruction to render smooth isosurfaces and to compute accurate derivatives for high-quality shading effects. We also present a novel, adaptive preintegration scheme to improve the efficiency of the ray casting algorithm by reducing the overall number of function evaluations, and an efficient implementation of our framework exploiting modern graphics hardware. The resulting system enables high-quality volume integration and shaded isosurface rendering for regular and irregular volume data. PMID:18988986

Ledergerber, Christian; Guennebaud, Gaël; Meyer, Miriah; Bächer, Moritz; Pfister, Hanspeter

2008-01-01

344

DentalCast  

NSDL National Science Digital Library

DentalCast is a network of Internet radio and video that brings the latest information about dental technology and clinical techniques to your computer or MP3 Player. DentalCast offers both Audio and Video episodes that can be accessed directly from your PC or users can subscribe to either or both audio and video via iTunes. Episodes available include: recognizing sleep apnea patients in your practice; Discussion of how a new dental product comes to the market; video of denture waxup techniques; and Dental Anxiety: An Integrative Approach to Treatment â?? to name only a few. These video and audio podcasts will be useful to those studying to be in the dental fields as well as for those teaching or practicing.

345

Effects of solidification structure and aging condition on cyclic stress–strain response in Al–7% Si–0.4% Mg cast alloys  

Microsoft Academic Search

Stress–strain response under cyclic loading at fixed plastic strain amplitude condition was examined for age-hardenable Al–7% Si–0.4% Mg (A356) cast alloys. The specimens examined include the cast alloys with ordinary dendrite structure and semi-liquid die-cast alloys with fine effective grain structure. Al–0.5% Mg–0.4% Si (6063) alloy was also tested for comparison. Special attention was paid to the effect of solidification

Sang-Won Han; Koji Katsumata; Shinji Kumai; Akikazu Sato

2002-01-01

346

EFFECT OF CAST RECTIFIERS ON THE MARGINAL FIT OF UCLA ABUTMENTS  

PubMed Central

Objectives: This study assessed the effect of cast rectifiers on the marginal misfit of cast UCLA abutments compared to premachined UCLA abutments. The influence of casting and porcelain baking on the marginal misfit of these components was also investigated. Methods: Two groups were analyzed: test group – 10 cast UCLA abutments, finished with cast rectifier and submitted to ceramic application; control group – 10 premachined UCLA abutments, cast with noble metal alloy and submitted to ceramic application. Vertical misfit measurements were performed under light microscopy. In the test group, measurements were performed before and after the use of cast rectifiers, and after ceramic application. In the control group, measurements were performed before and after casting, and after ceramic application. Data were submitted to statistical analysis by ANOVA and Tukey's test (?= 5%). Results: The use of cast rectifiers significantly reduced the marginal misfit of cast UCLA abutments (from 25.68?m to 14.83?m; p<0.05). After ceramic application, the rectified cylinders presented misfit values (16.18?m) similar to those of premachined components (14.3 ?m). Casting of the premachined UCLA abutments altered the marginal misfit of these components (from 9.63 ?m to 14.6 ?m; p<0.05). There were no significant changes after porcelain baking, in both groups. Conclusion: The use of cast rectifiers reduced the vertical misfit of cast UCLA abutments. Even with carefully performed laboratory steps, changes at the implant interface of premachined UCLA abutments occurred. Ceramic application did not alter the marginal misfit values of UCLA abutments. PMID:19089125

Jaime, Ana Paula Gumieiro; de Vasconcellos, Diego Klee; Mesquita, Alfredo Mikail Melo; Kimpara, Estevão Tomomitsu; Bottino, Marco Antonio

2007-01-01

347

[Casting faults and structural studies on bonded alloys comparing centrifugal castings and vacuum pressure castings].  

PubMed

The casting processes in use today such as centrifugal casting and vacuum pressure casting were compared with one another. An effort was made to answer the question whether the occurrence of shrink cavities and the mean diameter of the grain of the alloy is dependent on the method of casting. 80 crowns were made by both processes from the baked alloys Degudent Universal, Degudent N and the trial alloy 4437 of the firm Degusa. Slice sections were examined for macro and micro-porosity and the structural appearance was evaluated by linear analysis. Statistical analysis showed that casting faults and casting structure is independent of the method used and their causes must be found in the conditions of casting and the composition of the alloy. PMID:352670

Fuchs, P; Küfmann, W

1978-07-01

348

The application of higher than atmospheric pressure to the risers of steel castings has been reported in the foundry literature going back at least to the 1940's. In these reports, the  

E-print Network

in steel foundries. A series of three casting trials were performed comparing 3" thick by 6" wide plate and soundness be improved. This paper reports on recent efforts by the authors and Harrison Steel Castings at the Harrison Steel Casting Company. The trials tested the methods' capabilities to maintain pressure tightness

Beckermann, Christoph

349

Dying Piñon Pine  

USGS Multimedia Gallery

A massive forest die-off is projected to occur more frequently in the Southwest. Piñon pines, normally evergreen, have reddish-brown foliage in October 2002 (left). By May 2004 (right), the dead piñon pines have lost all their needles, exposing gray trunks and branches. The photos were...

350

Rund um die Wirtschaftswissenschaftliche  

E-print Network

Studienleistungen, die an anderen deutschen Universitäten oder im Ausland erbracht wurden, wird durch das ECTS-System Internationale Büro. BWL in sieben Schwerpunkten: Accounting, Tax- ation and Capital Markets / Corporate Governance: Management and Corporate Control / Decision & Risk / Education, Labour Relations and Employment

Knüpfer, Christian

351

Dying to Play.  

ERIC Educational Resources Information Center

In August 1995, a young football player died as a result of heat exhaustion suffered on the first day of football practice in Arkansas. Spurred by this tragedy, the district made some changes that every school district with an athletic program should consider. These include using a heat-stress monitor; abandoning the practice of group physical…

Miller, John K.

1998-01-01

352

Die Stoffwechselsituation des Reizleitungssystems  

Microsoft Academic Search

Zusammenfassung Die spezifische Muskulatur des Reizleitungssystems unterscheidet sich u. a. von der Arbeitsmuskulatur durch ein vermindertes Vorkommen von Sarkosomen, eine schwächere Bernsteinsäuredehydrogenase-und Oxydasereaktion und einen geringeren Sauerstoffverbrauch. Wir schließen daraus auf einen stoffwechselmäßigen Unterschied zwischen den beiden Muskelarten und stellen zur Diskussion, ob das Reizleitungssystem relativ unabhängig von der Sauerstoffversorgung ist. Das Reizleitungssystem weist auch unter Thyroxinbelastung einen zäh festgehaltenen,

Th. H. Schiebler; M. Stark; R. Caesar

1956-01-01

353

When Somebody Dies  

MedlinePLUS

... after the body dies is often called the "soul" or "spirit." Some people believe the soul is the part of a human that loves, ... one really knows what happens to a person's soul after death. There are many different beliefs about ...

354

Die Kosmologie der Griechen.  

NASA Astrophysics Data System (ADS)

Contents: 1. Mythische Eier. 2. Thales-Welten. 3. "Alles ist voller Götter". 4. Griechische Astronomie. 5. "Rettung der Phänomene". 6. Aristotelische Kosmololgie. 7. Aristoteles-Welt und Platon-Welt. 8. Noch einmal: die Göttlichkeit der Welt. 9. Griechischer Idealismus.

Mittelstraß, J.

355

Archimedes, und die gestorten  

E-print Network

Archimedes, und die gest¨orten Kreise Vortrag im Naturhistorischen Museum Mainz Prof. Dr. Duco van;Archimedes Gem¨alde von Jusepe de Ribera (1630) (Madrid) #12;Archimedes Gem¨alde von Domenico Fetti (1620-241 #12;· 263: Friedensvertrag mit Rom · Fast f¨unfzig Jahre Frie- den! · Archimedes wird Berater am Hof

van Straten, Duco

356

HERAUSFORDERUNGEN FR DIE INFORMATIONSGESELLSCHAFT?  

E-print Network

. Vannevar Bush hat in seiner Vision die Innovation vorweggenommen, mit der Tim Berners Lee Jahrzehnte später in Stärken. Tim Berners-Lee hat empirisch eingelöst, was Vannevar Bush noch überwiegend als moralische nicht bekannt ist. (So auch der Ansatz von Benussi (2005)) Auch Tim Berners Lee mit seiner genialen

Lutterbeck, Bernd

357

Dying at home  

PubMed Central

Abstract Objective To demonstrate that it is possible for a team of palliative care nurses in an urban centre to care for more than 50% of their terminally ill patients at home until they die, and that medical care delivered in the home is a determining factor in death at home versus death in a hospital. Design Analysis of place of death of terminally ill patients who died in 2012 and 2013 (N = 212) and who had been cared for by palliative care nurses, by type of medical care. Setting The centre local de services communautaires (CLSC) in Verdun, Que, an urban neighbourhood in southwest Montreal. Participants A total of 212 terminally ill patients. Main outcome measures Rate of deaths at home. Results Of the 212 patients cared for at home by palliative care nurses, 56.6% died at home; 62.6% received medical home care from CLSC physicians, compared with 5.0% who did not receive medical home care from any physician. Conclusion Combined with a straightforward restructuring of the nursing care delivered by CLSCs, development of medical services delivered in the home would enable the more than 50% of terminally ill patients in Quebec who are cared for by CLSCs to die at home—something that most of them wish for. PMID:25873716

Kiyanda, Brigitte Gagnon; Dechêne, Geneviève; Marchand, Robert

2015-01-01

358

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

PubMed

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

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

2014-02-01

359

AIS/DOE Technology Roadmap Program: Strip Casting: Anticipating New Routes To Steel Sheet  

SciTech Connect

To determine the potential for strip casting in the steel industry and to develop the fundamental knowledge necessary to allow the role of strip casting in the modern steel industry to be understood. Based upon a study of carbon steel strip castings that were either produced for the program at British Steel or were received from a pre-commercial production machine, the following conclusions were made. Strip casting of carbon steels is technically feasible for sheet material from slightly less than 1 mm thick to 3 mm thick, and, assuming that it is economically viable, it will be first applied in carbon steel markets that do not require stringent surface quality or extensive forming. The potential of strip casting as a casting process to be developed for steel castings is very high as the cast strip has some very novel characteristics. Direct cast carbon strip has better surface quality, shape and profile than any other casting process currently available. The more rapidly solidified structure of direct cast strip tends to be strong with low ductility; however, with adequate thermal treatment, it is possible to develop a variety of properties from the same grade. The process is more amenable at this time to production tonnages per year of the order of 500,000 tons and as such will first find niche type applications. This technology is an additional technology for steel production and will be in addition to, rather than a replacement for, current casting machines.

Prof. Alan W. Camb; Prof. Anthony Rollett

2001-08-31

360

Application of gel-casting to the fabrication of 1-3 piezoelectric ceramic-polymer composites for high-frequency ultrasound devices  

NASA Astrophysics Data System (ADS)

A modified gel-casting technique was used to fabricate a 1-3 piezoelectric ceramic/polymer composite substrate formed by irregular-shaped pillar arrays of small dimensions and kerfs. This technique involves the polymerization of aqueous piezoelectric (PZT) suspensions with added water-soluble epoxy resin and polyamine-based hardener that lead to high strength, high density and resilient ceramic bodies. Soft micromoulding was used to shape the ceramic segments, and micropillars with lateral features down to 4 µm and height-to-width aspect ratios of ˜10 were achieved. The composite exhibited a clear thickness resonance mode at approximately 70 MHz and a keff ˜ 0.51, demonstrating that the ceramic micropillars possess good electrical properties. Furthermore, gel-casting allows the fabrication of ceramic structures with non-conventional shapes; hence, device design is not limited by the standard fabrication methods. This is of particular benefit for high-frequency transducers where the critical design dimensions are reduced.

García-Gancedo, L.; Olhero, S. M.; Alves, F. J.; Ferreira, J. M. F.; Demoré, C. E. M.; Cochran, S.; Button, T. W.

2012-12-01

361

Modal Vibration Analysis of Large Castings  

NASA Technical Reports Server (NTRS)

The art of experimental modal vibration analysis (MVA) has been extended to apply to large castings. This extension was made to enable the use of experimental MVA as a relatively inexpensive, simple means of assessing the internal structural integrity of tread shoes of crawler transporters used to move spacecraft to the launch pad at Kennedy Space Center. Each tread shoe is made from cast iron and weighs about a ton (has a mass .907 kg). The present extended version of experimental MVA could also be applied to other large castings. It could be especially useful to manufacturers as a means of rapidly discriminating against large castings that contain unacceptably large concentrations of internal defects. The use of experimental MVA to assess structural integrity is not new. What are new here are those aspects of the extension of experimental MVA that pertain to the application of MVA to objects so massive that it may not be practical or cost effective to mount them in special test fixtures that impose special test boundary conditions to test them in place under normal conditions of use.

Werlink, Rudolph J.; Margasahayam, Ravi N.

2009-01-01

362

First Results of Energy Saving at Process Redesign of Die Forging Al-Alloys  

NASA Astrophysics Data System (ADS)

The contribution deals with eco-friendly solutions for shortened production chains of forging light alloys. During the die forging operations a remarkable amount of material goes into the flash and later on into chips during finish machining. These low value side products are rich with embedded energy therefore recycling or reprocessing could be very energy saving procedure. In cooperation with a die forging company a shortened reprocessing cycle has been studied starting from re-melting the forging flash and without additional heating to cast preforms for subsequent die forging. As such preforms have not as good formability characteristics as those done from extruded billets the isothermal forging process has been adopted. First results showed that without cracks and other defects the formability is sufficient for a broad spectrum of forgings. To improve the formability a homogenization process of cast preforms has been implemented. As the process started immediately after casting, amount of additional energy for heating was minimized. To reduce voids forging process was redesigned in a way to assure greater hydrostatic pressures in parts during forging. First results were promising therefore research is going towards improving processes without adding significantly more energy as it is needed for casting with homogenization and die forging.

Pepelnjak, Tomaž; Kuzman, Karl; Kokol, Anton

2011-05-01

363

First Results of Energy Saving at Process Redesign of Die Forging Al-Alloys  

SciTech Connect

The contribution deals with eco-friendly solutions for shortened production chains of forging light alloys. During the die forging operations a remarkable amount of material goes into the flash and later on into chips during finish machining. These low value side products are rich with embedded energy therefore recycling or reprocessing could be very energy saving procedure.In cooperation with a die forging company a shortened reprocessing cycle has been studied starting from re-melting the forging flash and without additional heating to cast preforms for subsequent die forging. As such preforms have not as good formability characteristics as those done from extruded billets the isothermal forging process has been adopted. First results showed that without cracks and other defects the formability is sufficient for a broad spectrum of forgings.To improve the formability a homogenization process of cast preforms has been implemented. As the process started immediately after casting, amount of additional energy for heating was minimized. To reduce voids forging process was redesigned in a way to assure greater hydrostatic pressures in parts during forging. First results were promising therefore research is going towards improving processes without adding significantly more energy as it is needed for casting with homogenization and die forging.

Pepelnjak, Tomaz; Kuzman, Karl [Faculty of Mechanical Engineering, Askerceva 6, SI-1000 Ljubljana (Slovenia); Kokol, Anton [Kovinar-forging company, Kovaska cesta 12, SI-3205 Vitanje (Slovenia)

2011-05-04

364

LOST FOAM CASTING OF MAGNESIUM ALLOYS  

SciTech Connect

The lost foam casting process has been successfully used for making aluminum and cast iron thin walled castings of complex geometries. Little work has been carried out on cast magnesium alloys using the lost foam process. The article describes the research activities at Oak Ridge National Laboratory and Tennessee Technological University on lost foam casting of magnesium alloys. The work was focused on castings of simple geometries such as plate castings and window castings. The plate castings were designed to investigate the mold filling characteristics of magnesium and aluminum alloys using an infrared camera. The pate castings were then characterized for porosity distribution. The window castings were made to test the castability of the alloys under lost foam conditions. Significant differences between lost foam aluminum casting and lost foam magnesium casting have been observed.

Han, Qingyou [ORNL; Dinwiddie, Ralph Barton [ORNL; Sklad, Philip S [ORNL; Currie, Kenneth [Tennessee Technological University; Abdelrahman, Mohamed [Tennessee Technological University; Vondra, Fred [Tennessee Technological University; Walford, Graham [Walford Technologies; Nolan, Dennis J [Foseco-Morval

2007-01-01

365

Thermostable cast stone from slag  

Microsoft Academic Search

Commercial production of refractory cast stone products in the USSR has been set up at the Pervoural'sk Mining Equipment Repair Plant (600 tonnes\\/year) and at the stone casting facility of the Scientific-Research and Planning institute of Industrial Construction (Krivoi Rog, 300 tonnes\\/year). The refractory cast stone produced in the Soviet Union meets only a small part of demand. Investigation and

I. I. Bykov; Zh. D. Bogatyreva; V. A. Bogno; L. F. Lekarenko

1990-01-01

366

Steel casting by diffusion solidification  

Microsoft Academic Search

A new process for casting and welding carbon steels is described in which carbon diffuses isothermally or adiabatically within\\u000a an intimate mixture of solid low carbon steel and high carbon liquid iron to effect solidification and subsequent homogenization\\u000a with respect to carbon. Advantages over conventional casting processes and products result from 1) 150 to 200°C lower casting\\u000a temperature; 2) reduced

George Langford; Robert E. Cunningham

1978-01-01

367

Should assisted dying be lawful?  

PubMed

Calls for a change in the law to allow strictly controlled forms of assisted dying in the UK have resurfaced following a much-publicised storyline on the subject on the TV soap opera Coronation Street and the impending debate on Lord Falconer's Assisted Dying Bill in the House of Lords. This article reviews the current stance of the law on euthanasia and assisted dying and considers Lord Falconer's attempts to reform the law through the Assisted Dying Bill. PMID:24514111

Griffith, Richard

2014-02-01

368

The Influence of Friction Stir Processing on Microstructure and Properties of a Cast Nickel Aluminum Bronze Material  

Microsoft Academic Search

Cast nickel-aluminum bronze (NAB) is specified for many marine applications due to its excellent corrosion resistance. Improved mechanical properties may be attainable using friction stir processing (FSP) to achieve localized microstructure modification in cast material, and convert an as-cast microstructure to a wrought condition in the absence of macroscopic shape change. In effect, FSP provides a means of surface hardening

Keiichiro Oh-ishi; A. M. Cuevas; Douglas L. Swisher; Terry R. McNelley

2003-01-01

369

78 FR 74163 - Johnstown Specialty Castings Inc., a Subsidiary of WHEMCO, Including On-Site Leased Workers From...  

Federal Register 2010, 2011, 2012, 2013, 2014

...TA-W-82,671] Johnstown Specialty Castings Inc., a Subsidiary of WHEMCO, Including...applicable to workers of Johnstown Specialty Castings, Inc., a subsidiary of WHEMCO, Johnstown...Pennsylvania location of Johnstown Specialty Castings, Inc., a subsidiary of WHEMCO....

2013-12-10

370

Hickey, W8201, casts 11-18 Hickey, W8201, casts 11-18, page 1  

E-print Network

Hickey, W8201, casts 11-18 Hickey, W8201, casts 11-18, page 1 CTD011 #12;Hickey, W8201, casts 11-18 Hickey, W8201, casts 11-18, page 2 CTD011 #12;Hickey, W8201, casts 11-18 Hickey, W8201, casts 11-18, page 3 CTD011 #12;Hickey, W8201, casts 11-18 Hickey, W8201, casts 11-18, page 4 CTD011 #12;Hickey, W8201

Hickey, Barbara

371

Hickey, TT162, Casts 88-92 Hickey, TT162, Casts 88-92, page 1  

E-print Network

Hickey, TT162, Casts 88-92 Hickey, TT162, Casts 88-92, page 1 CTD088 #12;Hickey, TT162, Casts 88-92 Hickey, TT162, Casts 88-92, page 2 CTD088 #12;Hickey, TT162, Casts 88-92 Hickey, TT162, Casts 88-92, page 3 CTD088 #12;Hickey, TT162, Casts 88-92 Hickey, TT162, Casts 88-92, page 4 CTD088 #12;Hickey, TT162

Hickey, Barbara

372

Hickey, TT162, Casts 17-24 Hickey, TT162, Casts 17-24, page 1  

E-print Network

Hickey, TT162, Casts 17-24 Hickey, TT162, Casts 17-24, page 1 CTD017 #12;Hickey, TT162, Casts 17-24 Hickey, TT162, Casts 17-24, page 2 CTD017 #12;Hickey, TT162, Casts 17-24 Hickey, TT162, Casts 17-24, page 3 CTD018 #12;Hickey, TT162, Casts 17-24 Hickey, TT162, Casts 17-24, page 4 CTD018 #12;Hickey, TT162

Hickey, Barbara

373

Hickey, TT162, Casts 38-47 Hickey, TT162, Casts 38-47, page 1  

E-print Network

Hickey, TT162, Casts 38-47 Hickey, TT162, Casts 38-47, page 1 CTD038 #12;Hickey, TT162, Casts 38-47 Hickey, TT162, Casts 38-47, page 2 CTD039 #12;Hickey, TT162, Casts 38-47 Hickey, TT162, Casts 38-47, page 3 CTD039 #12;Hickey, TT162, Casts 38-47 Hickey, TT162, Casts 38-47, page 4 CTD040 #12;Hickey, TT162

Hickey, Barbara

374

Hickey, TT136, casts 56-76 Hickey, TT136, casts 56-76, page 1  

E-print Network

Hickey, TT136, casts 56-76 Hickey, TT136, casts 56-76, page 1 CTD056 #12;Hickey, TT136, casts 56-76 Hickey, TT136, casts 56-76, page 2 CTD056 #12;Hickey, TT136, casts 56-76 Hickey, TT136, casts 56-76, page 3 CTD056 #12;Hickey, TT136, casts 56-76 Hickey, TT136, casts 56-76, page 4 CTD056 #12;Hickey, TT136

Hickey, Barbara

375

Hickey, W8201, Casts 1-10 Hickey, W8201, Casts 1-10, page 1  

E-print Network

CTD001 Hickey, W8201, Casts 1-10 Hickey, W8201, Casts 1-10, page 1 #12;CTD001 Hickey, W8201, Casts 1-10 Hickey, W8201, Casts 1-10, page 2 #12;CTD002 Hickey, W8201, Casts 1-10 Hickey, W8201, Casts 1-10, page 3 #12;CTD002 Hickey, W8201, Casts 1-10 Hickey, W8201, Casts 1-10, page 4 #12;CTD003 Hickey, W8201

Hickey, Barbara

376

Hickey, TT162, Casts 83-87 Hickey, TT162, Casts 83-87, page 1  

E-print Network

Hickey, TT162, Casts 83-87 Hickey, TT162, Casts 83-87, page 1 CTD083 #12;Hickey, TT162, Casts 83-87 Hickey, TT162, Casts 83-87, page 2 CTD083 #12;Hickey, TT162, Casts 83-87 Hickey, TT162, Casts 83-87, page 3 CTD083 #12;Hickey, TT162, Casts 83-87 Hickey, TT162, Casts 83-87, page 4 CTD083 #12;Hickey, TT162

Hickey, Barbara

377

Hickey, TT136, casts 11-20 Hickey, TT136, casts 11-20, page 1  

E-print Network

Hickey, TT136, casts 11-20 Hickey, TT136, casts 11-20, page 1 CTD011 #12;Hickey, TT136, casts 11-20 Hickey, TT136, casts 11-20, page 2 CTD011 #12;Hickey, TT136, casts 11-20 Hickey, TT136, casts 11-20, page 3 CTD012 #12;Hickey, TT136, casts 11-20 Hickey, TT136, casts 11-20, page 4 CTD013 #12;Hickey, TT136

Hickey, Barbara

378

Hickey, TT136, casts 46-47 Hickey, TT136, casts 46-47, page 1  

E-print Network

Hickey, TT136, casts 46-47 Hickey, TT136, casts 46-47, page 1 CTD046 #12;Hickey, TT136, casts 46-47 Hickey, TT136, casts 46-47, page 2 CTD046 #12;Hickey, TT136, casts 46-47 Hickey, TT136, casts 46-47, page 3 CTD046 #12;Hickey, TT136, casts 46-47 Hickey, TT136, casts 46-47, page 4 CTD046 #12;Hickey, TT136

Hickey, Barbara

379

Hickey, TT162, Casts 56-62 Hickey, TT162, Casts 56-62, page 1  

E-print Network

Hickey, TT162, Casts 56-62 Hickey, TT162, Casts 56-62, page 1 CTD056 #12;Hickey, TT162, Casts 56-62 Hickey, TT162, Casts 56-62, page 2 CTD056 #12;Hickey, TT162, Casts 56-62 Hickey, TT162, Casts 56-62, page 3 CTD056 #12;Hickey, TT162, Casts 56-62 Hickey, TT162, Casts 56-62, page 4 CTD056 #12;Hickey, TT162

Hickey, Barbara

380

Hickey, TT162, Casts 63-72 Hickey, TT162, Casts 63-72, page 1  

E-print Network

Hickey, TT162, Casts 63-72 Hickey, TT162, Casts 63-72, page 1 CTD063 #12;Hickey, TT162, Casts 63-72 Hickey, TT162, Casts 63-72, page 2 CTD063 #12;Hickey, TT162, Casts 63-72 Hickey, TT162, Casts 63-72, page 3 CTD063 #12;Hickey, TT162, Casts 63-72 Hickey, TT162, Casts 63-72, page 4 CTD064 #12;Hickey, TT162

Hickey, Barbara

381

Hickey, TT162, Casts 48-49 Hickey, TT162, Casts 48-49, page 1  

E-print Network

Hickey, TT162, Casts 48-49 Hickey, TT162, Casts 48-49, page 1 CTD048 #12;Hickey, TT162, Casts 48-49 Hickey, TT162, Casts 48-49, page 2 CTD048 #12;Hickey, TT162, Casts 48-49 Hickey, TT162, Casts 48-49, page 3 CTD048 #12;Hickey, TT162, Casts 48-49 Hickey, TT162, Casts 48-49, page 4 CTD048 #12;Hickey, TT162

Hickey, Barbara

382

Hickey, TT136, casts 41-43 Hickey, TT136, casts 41-43, page 1  

E-print Network

CTD041 Hickey, TT136, casts 41-43 Hickey, TT136, casts 41-43, page 1 #12;CTD041 Hickey, TT136, casts 41-43 Hickey, TT136, casts 41-43, page 2 #12;CTD041 Hickey, TT136, casts 41-43 Hickey, TT136, casts 41-43, page 3 #12;CTD041 Hickey, TT136, casts 41-43 Hickey, TT136, casts 41-43, page 4 #12;CTD041

Hickey, Barbara

383

Hickey, TT136, casts 96-97 Hickey, TT136, casts 96-97, page 1  

E-print Network

Hickey, TT136, casts 96-97 Hickey, TT136, casts 96-97, page 1 CTD096 #12;Hickey, TT136, casts 96-97 Hickey, TT136, casts 96-97, page 2 CTD096 #12;Hickey, TT136, casts 96-97 Hickey, TT136, casts 96-97, page 3 CTD096 #12;Hickey, TT136, casts 96-97 Hickey, TT136, casts 96-97, page 4 CTD096 #12;Hickey, TT136

Hickey, Barbara

384

Hickey, TT136, casts 98-99 Hickey, TT136, casts 98-99, page 1  

E-print Network

Hickey, TT136, casts 98-99 Hickey, TT136, casts 98-99, page 1 CTD098 #12;Hickey, TT136, casts 98-99 Hickey, TT136, casts 98-99, page 2 CTD098 #12;Hickey, TT136, casts 98-99 Hickey, TT136, casts 98-99, page 3 CTD098 #12;Hickey, TT136, casts 98-99 Hickey, TT136, casts 98-99, page 4 CTD098 #12;Hickey, TT136

Hickey, Barbara

385

Hickey, TT136, casts 52-55 Hickey, TT136, casts 52-55, pager 1  

E-print Network

Hickey, TT136, casts 52-55 Hickey, TT136, casts 52-55, pager 1 CTD052 #12;Hickey, TT136, casts 52-55 Hickey, TT136, casts 52-55, pager 2 CTD052 #12;Hickey, TT136, casts 52-55 Hickey, TT136, casts 52-55, pager 3 CTD052 #12;Hickey, TT136, casts 52-55 Hickey, TT136, casts 52-55, pager 4 CTD052 #12;Hickey, TT

Hickey, Barbara

386

Hickey, TT136, casts 91-95 Hickey, TT136, casts 91-95, page 1  

E-print Network

Hickey, TT136, casts 91-95 Hickey, TT136, casts 91-95, page 1 CTD091 #12;Hickey, TT136, casts 91-95 Hickey, TT136, casts 91-95, page 2 CTD091 #12;Hickey, TT136, casts 91-95 Hickey, TT136, casts 91-95, page 3 CTD091 #12;Hickey, TT136, casts 91-95 Hickey, TT136, casts 91-95, page 4 CTD091 #12;Hickey, TT136

Hickey, Barbara

387

Hickey, W8201, casts 26-32 Hickey, W8201, casts 26-32, page 1  

E-print Network

Hickey, W8201, casts 26-32 Hickey, W8201, casts 26-32, page 1 CTD026 #12;Hickey, W8201, casts 26-32 Hickey, W8201, casts 26-32, page 2 CTD026 #12;Hickey, W8201, casts 26-32 Hickey, W8201, casts 26-32, page 3 CTD027 #12;Hickey, W8201, casts 26-32 Hickey, W8201, casts 26-32, page 4 CTD027 #12;Hickey, W8201

Hickey, Barbara

388

Hickey, TT136, casts 21-26 Hickey, TT136, casts 21-26, page 1  

E-print Network

Hickey, TT136, casts 21-26 Hickey, TT136, casts 21-26, page 1 CTD021 #12;Hickey, TT136, casts 21-26 Hickey, TT136, casts 21-26, page 2 CTD021 #12;Hickey, TT136, casts 21-26 Hickey, TT136, casts 21-26, page 3 CTD021 #12;Hickey, TT136, casts 21-26 Hickey, TT136, casts 21-26, page 4 CTD021 #12;Hickey, TT136

Hickey, Barbara

389

Hickey, TT136, casts 77-90 Hickey, TT136, casts 77-90, page 1  

E-print Network

Hickey, TT136, casts 77-90 Hickey, TT136, casts 77-90, page 1 CTD077 #12;Hickey, TT136, casts 77-90 Hickey, TT136, casts 77-90, page 2 CTD077 #12;Hickey, TT136, casts 77-90 Hickey, TT136, casts 77-90, page 3 CTD077 #12;Hickey, TT136, casts 77-90 Hickey, TT136, casts 77-90, page 4 CTD077 #12;Hickey, TT136

Hickey, Barbara

390

Hickey, TT136, casts 48, 49, 51 Hickey, TT136, casts 48, 49, 51, page 1  

E-print Network

Hickey, TT136, casts 48, 49, 51 Hickey, TT136, casts 48, 49, 51, page 1 CTD048 #12;Hickey, TT136, casts 48, 49, 51 Hickey, TT136, casts 48, 49, 51, page 2 CTD048 #12;Hickey, TT136, casts 48, 49, 51 Hickey, TT136, casts 48, 49, 51, page 3 CTD048 #12;Hickey, TT136, casts 48, 49, 51 Hickey, TT136, casts

Hickey, Barbara

391

Hickey, TT136, casts 37-40 Hickey, TT136, casts 37-40, page 1  

E-print Network

CTD037 Hickey, TT136, casts 37-40 Hickey, TT136, casts 37-40, page 1 #12;CTD037 Hickey, TT136, casts 37-40 Hickey, TT136, casts 37-40, page 2 #12;CTD037 Hickey, TT136, casts 37-40 Hickey, TT136, casts 37-40, page 3 #12;CTD037 Hickey, TT136, casts 37-40 Hickey, TT136, casts 37-40, page 4 #12;CTD037

Hickey, Barbara

392

Hickey, TT136, casts 27-36 Hickey, TT136, casts 27-36, page 1  

E-print Network

Hickey, TT136, casts 27-36 Hickey, TT136, casts 27-36, page 1 CTD027 #12;Hickey, TT136, casts 27-36 Hickey, TT136, casts 27-36, page 2 CTD027 #12;Hickey, TT136, casts 27-36 Hickey, TT136, casts 27-36, page 3 CTD027 #12;Hickey, TT136, casts 27-36 Hickey, TT136, casts 27-36, page 4 CTD027 #12;Hickey, TT136

Hickey, Barbara

393

Hickey, TT162, Casts 73-82 Hickey, TT162, Casts 73-82, page 1  

E-print Network

Hickey, TT162, Casts 73-82 Hickey, TT162, Casts 73-82, page 1 CTD073 #12;Hickey, TT162, Casts 73-82 Hickey, TT162, Casts 73-82, page 2 CTD073 #12;Hickey, TT162, Casts 73-82 Hickey, TT162, Casts 73-82, page 3 CTD073 #12;Hickey, TT162, Casts 73-82 Hickey, TT162, Casts 73-82, page 4 CTD074 #12;Hickey, TT162

Hickey, Barbara

394

Hickey, TT136, casts 44-46 Hickey, TT136, casts 44-46, page 1  

E-print Network

Hickey, TT136, casts 44-46 Hickey, TT136, casts 44-46, page 1 CTD044 #12;Hickey, TT136, casts 44-46 Hickey, TT136, casts 44-46, page 2 CTD044 #12;Hickey, TT136, casts 44-46 Hickey, TT136, casts 44-46, page 3 CTD044 #12;Hickey, TT136, casts 44-46 Hickey, TT136, casts 44-46, page 4 CTD044 #12;Hickey, TT136

Hickey, Barbara

395

Der Islam und die Geschlechterfrage  

E-print Network

Der Islam und die Geschlechterfrage ­ theologische, gesellschaftliche, historische und praktische ausloten. Dazu gehört die Analyse der Wurzeln des Diskurses um ,,die Frau im Islam" aus einer and the Transmission of Religious Knowledge in Islam Prof. Dr. Asma Sayeed, University of California 10. Dezember

Steinhoff, Heinz-Jürgen

396

Section thickness-dependant interfacial heat transfer in squeeze casting of aluminum alloy A443  

NASA Astrophysics Data System (ADS)

Five-step castings of aluminum alloy A443 with different section thicknesses (2, 6, 8, 10, 20 mm) were squeezed under a hydraulic pressure of 60 MPa. Temperatures inside the P20 steel die mold and at the casting surface were recorded by fine type-K thermocouples. A numerical solution, i.e. inverse method was employed to determine the casting-die interfacial heat transfer coefficients (IHTCs). The results show the IHTCs initially reached a maximum peak value followed by a gradually decline to a lower level. With the applied pressure of 60MPa, the peak IHTC values from steps 1 to 5 varied from 5629 W/m2K to 9419 W/m2K. The section thickness affected IHTC peak values significantly. Compared to the thin steps at upper cavity, the lower thick steps obtained higher peak IHTCs and heat flux values due to high local pressures and high melt temperature.

Sun, Zhizhong; Zhang, Xuezhi; Hu, Henry; Niu, Xiaoping

2012-01-01

397

Columnar to equiaxed transition in high Cr white iron castings  

SciTech Connect

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.

Dogan, O.N. [Bureau of Mines, Albany, OR (United States)] [Bureau of Mines, Albany, OR (United States)

1996-07-15

398

Crystallinity in cast Nafion  

SciTech Connect

The performance of a polymer electrolyte fuel cell is critically dependent on the water uptake in the polymer electrolyte, usually Nafion. Nafion in solution is often painted onto the electrodes of the fuel cell. It is important that this cast Nafion film stay amorphous and not crystallize. Cast Nafion films, ca. 1 {micro}m thick, crystallized on silicon plates when kept in air at room temperature for a long time. The films contain large crystalline regions ranging from 0.5 mm to several millimeters in size. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) microspectroscopy have been used to investigate the crystalline and amorphous regions. The XRD shows two sharp peaks. One of the peaks is developed before the second one appears in the diffractogram, indicating that there might be two types of crystallizing processes. FTIR spectra of the amorphous and crystalline regions in the films show important differences. In the crystalline regions, the film contains the sulfonic acid at the end of the side chains; hence, the crystalline regions contain no water molecules. In the amorphous regions there is a complete proton transfer from the acid to the water molecules, and sulfonate groups are obtained.

Ludvigsson, M.; Lindgren, J.; Tegenfeldt, J.

2000-04-01

399

Liquid crystal polymer/polyethylene (LCP/PE) in-situ composite thin film: Effect of counter-rotating die on film structure and properties  

SciTech Connect

Polyethylene blends (LLDPE:HDPE {approx} 2:1 by wt.) used in NASA`s balloon film applications can be effectively reinforced by addition of a small amount of liquid crystalline polymer (LCP). Cast and blown PE films containing {approx} 10% LCP show an appreciable enhancement in tensile modulus {approx} 400% over that of the neat PE matrix. Anisotropy in these in-situ composites was reduced by controlling LCP molecular orientation via a counter-rotating (C/R) annular die. LCP/PE blend blown films with nearly isotropic properties are obtained. Based on microscopic studies, LCP domains were generally present as fibrils with diameters of {approx} 1-3 {mu}M and lengths of {approx} 100-300 {mu}M. Films, produced using a C/R die, had fibrillated LCP phases and variable orientation through the film thickness. Our project has focused on upgrading currently used PE materials by incorporation of liquid crystalline polymer (LCP) fiber into the PE matrix. Present modulus and yield stress of these existing PE materials are approximately {approx}220 MPa and {approx} 10 MPa, respectively. Previous studies of LCP/PE blends have demonstrated that with addition of {approx} 10% LCP, cast and blown films can be produced that have a modulus of {approx}400% over that of the neat PE matrix. This result is attributed to the self-reinforcement effect of LCP fibrillar structures of high aspect ratio, that developed under a strong elongational flow field created by a converging flow die adapter. However, mechanical properties of these LCP/PE blend films are highly anisotropic, which is not desirable for balloon film applications, as well as for a number of other engineering uses. Control of this anisotropic characteristic via manipulation of LCP fiber orientation during processing is key to overcoming structural limitations (low transverse properties) of conventionally extruded LCPs and their blends.

Chinsirikul, W.; Harrison, I.R. [Pennsylvania State Univ., University Park, PA (United States); Hsu, T.C. [Polymics, Ltd., State College, PA (United States)

1996-12-31

400

Management of Intolerance to Casting the Upper Extremities in Claustrophobic Patients  

PubMed Central

Introduction. Some patients showed unusual responses to the immobilization without any objective findings with casts in upper extremities. We hypothesized their that intolerance with excessive anxiety to casts is due to claustrophobia triggered by cast immobilization. The aim of this study is to analyze the relevance of cast immobilization to the feeling of claustrophobia and discover how to handle them. Methods. There were nine patients who showed the caustrophobic symptoms with their casts. They were assesed whether they were aware of their claustrophobis themselves. Further we investigated the alternative immobilization to casts. Results. Seven out of nine cases that were aware of their claustrophobic tendencies either were given removable splints initially or had the casts converted to removable splints when they exhibited symptoms. The two patients who were unaware of their latent claustrophobic tendencies were identified when they showed similar claustrophobic symptoms to the previous patients soon after short arm cast application. We replaced the casts with removable splints. This resolved the issue in all cases. Conclusions. We should be aware of the claustrophobia if patients showed unusual responses to the immobilization without any objective findings with casts in upper extremities, where removal splint is practical alternative to cast to continue the treatment successfully. PMID:25379544

Nagura, Issei; Kanatani, Takako; Sumi, Masatoshi; Inui, Atsuyuki; Mifune, Yutaka; Kokubu, Takeshi; Kurosaka, Masahiro

2014-01-01

401

Low Background Micromegas in CAST  

E-print Network

Solar axions could be converted into x-rays inside the strong magnetic field of an axion helioscope, triggering the detection of this elusive particle. Low background x-ray detectors are an essential component for the sensitivity of these searches. We report on the latest developments of the Micromegas detectors for the CERN Axion Solar Telescope (CAST), including technological pathfinder activities for the future International Axion Observatory (IAXO). The use of low background techniques and the application of discrimination algorithms based on the high granularity of the readout have led to background levels below 10$^{-6}$ counts/keV/cm$^2$/s, more than a factor 100 lower than the first generation of Micromegas detectors. The best levels achieved at the Canfranc Underground Laboratory (LSC) are as low as 10$^{-7}$ counts/keV/cm$^2$/s, showing good prospects for the application of this technology in IAXO. The current background model, based on underground and surface measurements, is presented, as well as the strategies to further reduce the background level. Finally, we will describe the R&D paths to achieve sub-keV energy thresholds, which could broaden the physics case of axion helioscopes.

J. G. Garza; S. Aune; D. Calvet; J. F. Castel; F. E. Christensen; T. Dafni; M. Davenport; T. Decker; E. Ferrer-Ribas; J. Galán; J. A. García; I. Giomataris; R. M. Hill; F. J. Iguaz; I. G. Irastorza; A. C. Jakobsen; D. Jourde; H. Mirallas; I. Ortega; T. Papaevangelou; M. J. Pivovaroff; J. Ruz; A. Tomás; T. Vafeiadis; J. K. Vogel

2015-03-17

402

Low Background Micromegas in CAST  

E-print Network

Solar axions could be converted into x-rays inside the strong magnetic field of an axion helioscope, triggering the detection of this elusive particle. Low background x-ray detectors are an essential component for the sensitivity of these searches. We report on the latest developments of the Micromegas detectors for the CERN Axion Solar Telescope (CAST), including technological pathfinder activities for the future International Axion Observatory (IAXO). The use of low background techniques and the application of discrimination algorithms based on the high granularity of the readout have led to background levels below 10$^{-6}$ counts/keV/cm$^2$/s, more than a factor 100 lower than the first generation of Micromegas detectors. The best levels achieved at the Canfranc Underground Laboratory (LSC) are as low as 10$^{-7}$ counts/keV/cm$^2$/s, showing good prospects for the application of this technology in IAXO. The current background model, based on underground and surface measurements, is presented, as well as ...

Garza, J G; Calvet, D; Castel, J F; Christensen, F E; Dafni, T; Davenport, M; Decker, T; Ferrer-Ribas, E; Galán, J; García, J A; Giomataris, I; Hill, R M; Iguaz, F J; Irastorza, I G; Jakobsen, A C; Jourde, D; Mirallas, H; Ortega, I; Papaevangelou, T; Pivovaroff, M J; Ruz, J; Tomás, A; Vafeiadis, T; Vogel, J K

2015-01-01

403

Casting Freedom, 1860-1862  

ERIC Educational Resources Information Center

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…

Social Education, 2005

2005-01-01

404

PLUTONIUM FUEL-CASTING FACILITY  

Microsoft Academic Search

An induction-heated glove-box-enclosed casting facility was used at ; Hanford for the melting and casting of experimental plutonium-containing fuel ; alloys. The alloys are prepared in furnaces with removable clay-graphite ; crucibles, supported by rammed alumina containment shells. The furnaces, which ; have capacities of 25 and 50 pounds of aluminum, are tilted by rotary hydraulic ; actuators. Furnace power

L. G. Merker; C. H. Bloomster

1963-01-01

405

Biotransformation and ToxCast?  

EPA Science Inventory

A major focus in toxicology research is the development of in vitro methods to predict in vivo chemical toxicity. Within the EPA ToxCast program, a broad range of in vitro biochemical and cellular assays have been deployed to profile the biological activity of 320 ToxCast Phase I...

406

Lost-Soap Aluminum Casting.  

ERIC Educational Resources Information Center

Lost-wax casting in sterling silver is a costly experience for the average high school student. However, this jewelry process can be learned at no cost if scrap aluminum is used instead of silver, and soap bars are used instead of wax. This lost-soap aluminum casting process is described. (Author/KC)

Mihalow, Paula

1980-01-01

407

Volatile Species Retention During Metallic Fuel Casting  

SciTech Connect

Metallic nuclear fuels are candidate transmutation fuel forms for advanced fuel cycles. Through the operation of the Experimental Breeder Reactor II metallic nuclear fuels have been shown to be robust and easily manufactured. However, concerns have been raised concerning loss of americium during the casting process because of its high vapor pressure. In order to address these concerns a gaseous diffusion model was developed and a series of experiments using both manganese and samarium as surrogates for americium were conducted. The modeling results showed that volatility losses can be controlled to essentially no losses with a modest overpressure. Experimental results also showed volatile species retention down to no detectable losses through overpressure, although the loss values varied from the model results the same trend was seen. Bases on these results it is very probably that americium losses through volatility can be controlled to no detectable losses through application of a modest overpressure during casting.

Randall S. Fielding; Douglas L. Proter

2013-10-01

408

Flexible, Ultra-Thin, Embedded Die Packaging  

NASA Astrophysics Data System (ADS)

As thin, flexible electronics solutions become more robust, their integration into everyday life becomes more likely. With possible applications in wearable electronics, biomedical sensors, or 'peel and stick' sensors, the reliability of these ultra-thin packages becomes paramount. Likewise, the density achievable with stacked packages benefits greatly from thinner die stacks. To this end, techniques previously developed have demonstrated packages with die thinned to approximately 20mum. Covered in this work are methods for thinning and packaging silicon die, as well as information on common materials used in these processes. The author's contribution is a fabrication process for embedding ultra-thin (approximately 10mum) silicon die in polyimide substrates. This method is fully illustrated in Chapter 3 and enumerated in the Appendix as a quick reference. Additionally, thermal cycle testing of passive daisy chain assemblies has shown promising reliability data. Packages were mounted in three alignments: flat, concave, and convex, and placed into thermal shock testing. Finally, the author discusses possible applications for this fabrication process, including the fabrication of multi-chip-modules.

McPherson, Ryan J.

409

Rep. George Brown dies  

NASA Astrophysics Data System (ADS)

George E. Brown, ranking Democratic member of the U.S. House of Representatives Science Committee, died on July 15 at the age of 79 due to complications following a heart valve replacement last May. He was a strong advocate for science and environmental protection measures, and an independent thinker who sometimes found himself alone or far ahead of other people on issues. A congressman for 34 years who represented first the 29th Congressional District and then the 42nd District in California, Brown served on the science committee since 1965 and was chair from 1991 through 1994.

Showstack, Randy

410

Structural changes of radial forging die surface during service under thermo-mechanical fatigue  

Microsoft Academic Search

Radial forging is one of the modern open die forging techniques and has a wide application in producing machine parts. During operation at high temperatures, severe temperature change associated with mechanical loads and the resultant wearing of the die surface lead to intense variation in strain on the die surface. Therefore, under this operating condition, thermo-mechanical fatigue (TMF) occurs on

Fardin Nematzadeh; Mohammad Reza Akbarpour; Amir Hosein Kokabi; Seyed Khatiboleslam Sadrnezhaad

2009-01-01

411

Die Infrarot- und die Videookulographie – Alternativen zur Elektrookulographie?  

Microsoft Academic Search

Zusammenfassung  \\u000a Neuartige Technologien für die Registrierung von Augenbewegungen werfen die Frage auf, ob sie für die HNO-Heilkunde eine zuverlässige\\u000a und genaue Alternative zur bewährten Elektrookulographie darstellen. Ein direkter Vergleich zwischen drei verschiedenen Technologien,\\u000a nämlich der Elektrookulographie (EOG), der Videookulographie (VOG) und der Infrarotokulographie (IROG) wurde anhand der mittleren\\u000a Geschwindigkeit der langsamen Phase (SPV) während den 4 Routineuntersuchungen der Nystagmographieuntersuchungsbatterie, also

A. Schmid-Priscoveanu; J. H. J. Allum

1999-01-01

412

Computer-aided structural design of drawing dies for stamping processes based on functional features  

Microsoft Academic Search

This paper describes a structural design system for 3D drawing dies based on functional features using a minimum set of initial\\u000a information. In addition, it is also applicable to assign the functional features flexibly before accomplishing the design\\u000a of a solid model for the main parts of a drawing die, such as upper die, lower die, and blank holder. The

Bor-Tsuen Lin; Ming-Ren Chang; Hau-Luen Huang; Chun-Yu Liu

2009-01-01

413

Graphite/Thermoplastic-Pultrusion Die  

NASA Technical Reports Server (NTRS)

Attachment to extruder produces thermoplastic-impregnated graphite tape. Consists of profile die, fiber/resin collimator, and crosshead die body. Die designed to be attached to commercially available extrusion machine capable of extruding high-performance thermoplastics. Simple attachment to commercial extruder enables developers of composites to begin experimenting with large numbers of proprietary resins, fibers, and hybrid composite structures. With device, almost any possible fiber/resin combination fabricated.

Wilson, Maywood L.; Frye, Mark W.; Johnson, Gary S.; Stanfield, Clarence E.

1990-01-01

414

Strip casting with fluxing agent applied to casting roll  

DOEpatents

A strip caster for producing a continuous strip includes a tundish for containing a melt, a pair of horizontally disposed water cooled casting rolls and devices for electrostatically coating the outer peripheral chill surfaces of the casting rolls with a powder flux material. The casting rolls are juxtaposed relative to one another for forming a pouting basin for receiving the melt through a teeming tube thereby establishing a meniscus between the rolls for forming the strip. The melt is protected from the outside air by a non-oxidizing gas passed through a supply line to a sealing chamber. A preferred flux is boron oxide having a melting point of about 550 C. The flux coating enhances wetting of the steel melt to the casting roll and dissolves any metal oxide formed on the roll. 3 figs.

Williams, R.S.; O`Malley, R.J.; Sussman, R.C.

1997-07-29

415

Strip casting with fluxing agent applied to casting roll  

DOEpatents

A strip caster (10) for producing a continuous strip (24) includes a tundish (12) for containing a melt (14), a pair of horizontally disposed water cooled casting rolls (22) and devices (29) for electrostatically coating the outer peripheral chill surfaces (44) of the casting rolls with a powder flux material (56). The casting rolls are juxtaposed relative to one another for forming a pouting basin (18) for receiving the melt through a teeming tube (16) thereby establishing a meniscus (20) between the rolls for forming the strip. The melt is protected from the outside air by a non-oxidizing gas passed through a supply line (28) to a sealing chamber (26). A preferred flux is boron oxide having a melting point of about 550.degree. C. The flux coating enhances wetting of the steel melt to the casting roll and dissolves any metal oxide formed on the roll.

Williams, Robert S. (Fairfield, OH); O'Malley, Ronald J. (Miamisburg, OH); Sussman, Richard C. (West Chester, OH)

1997-01-01

416

Strip casting apparatus and method  

DOEpatents

Strip casting apparatus including a molten-metal-holding container and a nozzle to deposit molten metal onto a moving chill drum to directly cast continuous metallic strip. The nozzle body includes a slot bounded between a back and a front lip. The slot width exceeds about 20 times the gap distance between the nozzle and the chill drum surface. Preferably, the slot width exceeds 0.5 inch. This method of strip casting minimizes pressure drop, insuring better metal-to-chill-drum contact which promotes heat transfer and results in a better quality metallic strip.

Williams, Robert S. (Plum, PA); Baker, Donald F. (Hempfield, PA)

1988-01-01

417

Strip casting apparatus and method  

DOEpatents

Strip casting apparatus including a molten-metal-holding container and a nozzle to deposit molten metal onto a moving chill drum to directly cast continuous metallic strip. The nozzle body includes a slot bounded between a back and a front lip. The slot width exceeds about 20 times the gap distance between the nozzle and the chill drum surface. Preferably, the slot width exceeds 0.5 inch. This method of strip casting minimizes pressure drop, insuring better metal-to-chill-drum contact which promotes heat transfer and results in a better quality metallic strip. 6 figs.

Williams, R.S.; Baker, D.F.

1988-09-20

418

Rapid Manufacturing Via Metal Casting  

NSDL National Science Digital Library

The metal casting industry in undergoing significant changes and it is necessary for manufacturing engineering, industrial engineering and design students to recognize these changes. Rapid manufacturing has the potential to revolutionize the metal casting industry by greatly reducing the tooling requirements necessary to produce components. The lead times to produce complex components are being reduced from months to days. A large reduction in the traditional labor requirements for molders, coremakers, patternmakers, and toolmakers will occur. The numerous advantages of the process are discussed and the major limitations are also presented. The "Third Wave" has arrived in the metal casting industry.

Creese, Robert

419

Continuous Casting for Aluminum Sheet: a Product Perspective  

NASA Astrophysics Data System (ADS)

Continuous casting processes have been used successfully for more than 50 years to reduce the cost of manufacturing a variety of aluminum rolled products. Approximately 25% of North American flat-rolled sheet and foil is sourced from twin-roll cast or slab cast processes. Twin roll-casters provide a cost-effective solution for producing foil and light-gauge sheet from relatively low-alloyed aluminum (1xxx and 8xxx alloys). Slab casters, particularly Hazelett twin-belt machines, are well utilized in the production of 3xxx or 5xxx painted building products which require moderate strength and good corrosion resistance. Both foil and painted sheet are cost-sensitive commodity products with well-known metallurgical and quality requirements. There have been extensive trials and modest successes with continuous cast can stock and automotive sheet. However, they have not been widely adopted commercially due to generally lower levels of surface quality and formability compared with sheet produced from scalped direct chill (DC) cast ingot. The metallurgical requirements for can and auto sheet are considered in more detail with emphasis on the microstructural features which limit their application, e.g., particle distribution, grain size, and texture. Looking forward, slab casting offers the most viable opportunity for producing strong (i.e., higher alloy content), formable structural auto sheet with acceptable surface quality.

Sanders, Robert E.

2012-02-01

420

Hickey -TT136 casts 1-2 Hickey -TT136,Casts 1-2, page 1  

E-print Network

Hickey -TT136 casts 1-2 Hickey -TT136,Casts 1-2, page 1 CTD001 #12;Hickey -TT136 casts 1-2 Hickey -TT136,Casts 1-2, page 2 CTD001 #12;Hickey -TT136 casts 1-2 Hickey -TT136,Casts 1-2, page 3 CTD001 #12;Hickey -TT136 casts 1-2 Hickey -TT136,Casts 1-2, page 4 CTD001 #12;Hickey -TT136 casts 1-2 Hickey -TT136

Hickey, Barbara

421

Pre-Cast Gel Electrophoresis Guide  

E-print Network

Novex® Pre-Cast Gel Electrophoresis Guide Version B January 27, 2003 IM-1002 Novex® Pre-Cast Gel Electrophoresis Guide General information and protocols for using Novex® pre-cast gels www.invitrogen.com tech.............................................................................................................................28 Electrophoresis of Novex® Pre-Cast Gels

Kirschner, Marc W.

422

A Membrane Process for Recycling Die Lube from Wastewater Solutions  

SciTech Connect

An active-surface membrane technology was used to separate a die lube manufacturing wastewater stream consisting of various oils, hydrocarbons, heavy metals, and silicones. The ultrafiltration membranes reduced organics from initial oil and grease contents by 20?25X, carbon oxygen demand (COD) by 1.5 to 2X, and total organic carbon (TOC) by 0.6, while the biological oxygen demand (BOD) remained constant. The active-surface membranes were not fouled as badly as non-active-surface systems and the active-surface membrane flux levels were consistently higher and more stable than those of the non-active-surface membranes tested. Field testing demonstrated that the rotary microfilter can concentrate the die lube, i.e. remove the glycerin component, and produce a die lube suitable for recycling. The recycling system operated for six weeks with only seven cleaning cycles and no mechanical or electrical failures. Test data and quality records indicate that the die casting scrap was reduced from 8.4 to 7.8%. There is no doubt that this test yielded tremendous results. This separation process presents significant opportunities that can be evaluated further.

Peterson, E.S.; Trudeau, J.; Cleary, B.; Hackett, M.; Greene, W.A.

2003-04-30

423

A Membrane Process for Recycling Die Lube from Wastewater Solutions  

SciTech Connect

An active-surface membrane technology was used to separate a die lube manufacturing wastewater stream consisting of various oils, hydrocarbons, heavy metals, and silicones. The ultrafiltration membranes reduced organics from initial oil and grease contents by 20–25X, carbon oxygen demand (COD) by 1.5 to 2X, and total organic carbon (TOC) by 0.6, while the biological oxygen demand (BOD) remained constant. The active-surface membranes were not fouled as badly as non-active-surface systems and the active-surface membrane flux levels were consistently higher and more stable than those of the non-active-surface membranes tested. Field testing demonstrated that the rotary microfilter can concentrate the die lube, i.e. remove the glycerin component, and produce a die lube suitable for recycling. The recycling system operated for six weeks with only seven cleaning cycles and no mechanical or electrical failures. Test data and quality records indicate that the die casting scrap was reduced from 8.4 to 7.8%. There is no doubt that this test yielded tremendous results. This separation process presents significant opportunities that can be evaluated further.

Eric S. Peterson; Jessica Trudeau; Bill Cleary; Michael Hackett; William A. Greene

2003-04-01

424

Effect of chemical composition and superheat on macrostructure of high Cr white iron castings  

SciTech Connect

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)7C3 carbides in a steel matrix. 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. 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.

Dogan, Omer N.

2005-08-01

425

Casting evaluation of U-Zr alloy system fuel slug for SFR prepared by injection casting method  

SciTech Connect

Metal fuel slugs of U-Pu-Zr alloys for Sodium-cooled Fast Reactor (SFR) have conventionally been fabricated by a vacuum injection casting method. Recently, management of minor actinides (MA) became an important issue because direct disposal of the long-lived MA can be a long-term burden for a tentative repository up to several hundreds of thousand years. In order to recycle transuranic elements (TRU) retained in spent nuclear fuel, remote fabrication capability in a shielded hot cell should be prepared. Moreover, generation of long-lived radioactive wastes and loss of volatile species should be minimized during the recycled fuel fabrication step. In order to prevent the evaporation of volatile elements such as Am, alternative fabrication methods of metal fuel slugs have been studied applying gravity casting, and improved injection casting in KAERI, including melting under inert atmosphere. And then, metal fuel slugs were examined with casting soundness, density, chemical analysis, particle size distribution and microstructural characteristics. Based on these results there is a high level of confidence that Am losses will also be effectively controlled by application of a modest amount of overpressure. A surrogate fuel slug was generally soundly cast by improved injection casting method, melted fuel material under inert atmosphere.

Song, Hoon; Kim, Jong-Hwan; Kim, Ki-Hwan; Lee, Chan-Bock [Korea Atomic Energy Research Institute, Daedeok-daro 989-111, Yuseong-gu, Daejeon (Korea, Republic of)

2013-07-01

426

Imiminofluorescent Studies of Urinary Casts  

Microsoft Academic Search

Immunofluorescent staining of urinary casts of patients with chronic glomerulonephritis or with acute renal failure was performed. Urinary and cast Tamm-Horsfall muco-proteins were purified by a modified McQueen’s method. Rabbits were immunized by both of these materials to obtain antisera. The antigenic specificity of the prepared material was examined by the Ouchterlony gel diffusion method and immunoelectrophoresis. Indirect and direct

Yoshimasa Orita; Nobuko Imai; Naohiko Ueda; Keiko Aoki; Keiko Sugimoto; Akio Ando; Yoshihiro Fujiwara; Sho Hirano; Hiroshi Abe

1977-01-01

427

CAST STONE TECHNOLOGY FOR THE TREATMENT AND IMMOBILIZATION OF LOW-ACTIVITY WASTE  

SciTech Connect

Cast stone technology is being evaluated for potential application in the treatment and immobilization of Hanford low-activity waste. The purpose of this document is to provide background information on cast stone technology. The information provided in the report is mainly based on a pre-conceptual design completed in 2003.

MINWALL HJ

2011-04-08

428

Integration of reverse engineering and rapid technologies for rapid investment casting of gas turbine blades  

Microsoft Academic Search

The aim of this research work is to offer a unique procedure of integrated Reverse Engineering (RE) and Additive Manufacturing (AM) technologies through implementation of a comprehensive experimental study to present an extensive comparison between applicable rapid technologies for blade rapid investment casting. Different direct and indirect AM techniques were used to produce sacrificial investment casting patterns. In addition, an

Mohammad Vaezi; Davood Safaeian; Mohsen Shakeri

2011-01-01

429

Robustness of Ability Estimation to Multidimensionality in CAST with Implications to Test Assembly  

ERIC Educational Resources Information Center

Computer Adaptive Sequential Testing (CAST) is a test delivery model that combines features of the traditional conventional paper-and-pencil testing and item-based computerized adaptive testing (CAT). The basic structure of CAST is a panel composed of multiple testlets adaptively administered to examinees at different stages. Current applications…

Zhang, Yanwei; Nandakumar, Ratna

2006-01-01

430

Superplastic Response of Continuously Cast AZ31B Magnesium Sheet Alloys  

Microsoft Academic Search

Magnesium sheet is typically produced for commercial applications with the traditional DC-ingot casting method. As a result of the hexagonal close-packed crystallographic structure in magnesium, multiple rolling passes and annealing steps are required to reduce the thickness of the ingots. Thus, high fabrication costs characterize the creation of magnesium sheet suitable for common forming operations. Recently, continuous casting (CC) technology,

J. M. Boileau; P. A. Friedman; D. Q. Houston; S. G. Luckey

2010-01-01

431

Is it possible to decrease skin temperature with ice packs under casts and bandages?  

Microsoft Academic Search

Introduction  There is a general belief that the presence of a cast or a bandage eliminates the lowering effects of skin temperature when local cold therapy applied on the surface of the cast or bandage. The purpose of this study is to determine the magnitude of temperature changes at the skin of the ankle after the application of frozen ice packs

Guvenir Okcu; H. S. Yercan

2006-01-01

432

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

SciTech Connect

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.

Fasoyinu, Yemi [CanmetMATERIALS] [CanmetMATERIALS

2014-03-31

433

Informatics approach using metabolic reactivity classifiers to link in vitro to in vivo data in application to the ToxCast Phase I dataset  

EPA Science Inventory

Strategic combinations and tiered application of alternative testing methods to replace or minimize the use of animal models is attracting much attention. With the advancement of high throughput screening (HTS) assays and legacy databases providing in vivo testing results, suffic...

434

Quantitative measurement from vascular casts.  

PubMed

A review of quantitative measurements show casting materials shrink from 0.2 - 20% and have viscosities ranging from 1.4 - 100,000 centipoise. Blood vessels have highly variable mechanical properties. Some microvessels are very stiff having little change in dimensions with pressure. Larger vessels generally change diameter significantly but show highly variable changes in length with pressure. Perfusion fixation does not fix the dimensions of blood vessels. Dog carotid arteries well fixed with glutaraldehyde at physiologic dimensions retain approximately 20% of their elastic recoil circumferentially and approximately 30% longitudinally. We recommend vascular casting as a method of accurately measuring the vasculature if care is taken to use low shrinkage casting resins and maintain physiologic transmural pressures for the duration of any casting procedure, even if prefixation is used. We measured a approximately 10% error in our method of measuring both the size and location of periorificial atherosclerotic lesions from aortic casts. Little is known about how vascular smooth muscle tone changes during casting. PMID:2694360

Kratky, R G; Zeindler, C M; Lo, D K; Roach, M R

1989-09-01

435

A clinical perspective on dying  

PubMed Central

There is continuing need for dissemination of already available, clinically useful knowledge concerning the psychological needs of the seriously ill and dying. Against the changing social context of dying, some of our erroneous assumptions about these patients are explored and the genuine fears and personal needs are discussed. The implications of this knowledge for medical education are recognized. PMID:5074753

Janes, Robert G.

1972-01-01

436

Refractory films from spin-cast carbon  

SciTech Connect

A method is described to produce thin films of carbon by the pyrolysis of spin-cast polyacrylonitrile. Uv, ir, and Raman spectroscopies were employed to investigate the chemical structure of the films during pyrolysis. The electrical conductivity of films made in this way can be varied over several decades by changing the final temperature of carbonization. These films can also be photolithographically patterned and manipulated by wet and dry transfer techniques. As such, these films may have utility in microelectronic and hybrid microcircuit applications. 7 refs., 4 figs.

Renschler, C.L.; Sylwester, A.P.

1988-01-01

437

Two Piece Compaction Die Design  

SciTech Connect

Compaction dies used to create europium oxide and tantalum control plates were modeled using ANSYS 11.0. Two-piece designs were considered in order to make the dies easier to assemble than the five-piece dies that were previously used. The two areas of concern were the stresses at the interior corner of the die cavity and the distortion of the cavity wall due to the interference fit between the two pieces and the pressure exerted on the die during the compaction process. A successful die design would have stresses less than the yield stress of the material and a maximum wall distortion on the order of 0.0001 in. Design factors that were investigated include the inner corner radius, the value of the interference fit, the compaction force, the size of the cavity, and the outer radius and geometry of the outer ring. The results show that for the europium oxide die, a 0.01 in. diameter wire can be used to create the cavity, leading to a 0.0055 in. radius corner, if the radial interference fit is 0.003 in. For the tantalum die, the same wire can be used with a radial interference fit of 0.001 in. Also, for the europium oxide die with a 0.003 in. interference fit, it is possible to use a wire with a diameter of 0.006 in. for the wire burning process. Adding a 10% safety factor to the compaction force tends to lead to conservative estimates of the stresses but not for the wall distortion. However, when the 10% safety factor is removed, the wall distortion is not affected enough to discard the design. Finally, regarding the europium oxide die, when the cavity walls are increased by 0.002 in. per side or the outer ring is made to the same geometry as the tantalum die, all the stresses and wall distortions are within the desired range. Thus, the recommendation is to use a 0.006 in. diameter wire and a 0.003 in. interference fit for the europium oxide die and a 0.01 in. diameter wire and a 0.001 in. interference fit for the tantalum die. The dies can also be made to have the same outer geometry if desired.

Coffey, Ethan N [ORNL

2010-03-01

438

Die Euler-Mascheroni-Konstante Niloufar Rahi  

E-print Network

, die nach dem Mathe- matiker Leonhard Euler benannt ist: die Euler-Mascheroni-Konstante 0, 5772156649Die Euler-Mascheroni-Konstante Niloufar Rahi Ausarbeitung zum Vortrag in Überraschungen und Euler-Konstante die Rede ist, denkt man zuerst an die Zahl e 2, 7182818284 . . ., also den Wert der

Thäter, Gudrun

439

Zukunftssicherung für die Zeit nach der Krise  

Microsoft Academic Search

Die Studie berichtet zusammenfassend über die Ergebnisse der 9. HR-Expertenbefragung mit der Zeitschrift „Personalwirtschaft“ zum Thema „Employer Branding“. Berichtet wird über die Verbreitung des Employer Branding, die dabei verfolgten Ziele und die Instrumente, mit denen ein erfolgreiches Employer Branding realisiert werden kann. Eng damit verbunden sind ergänzende Fragen nach den Einflussfaktoren und den Gestaltungsmöglichkeiten der Arbeitgebermarke sowie nach den eingesetzten

Karl-Friedrich Ackermann; Martina Wehner

2009-01-01

440

Titan Casts Revealing Shadow  

NASA Astrophysics Data System (ADS)

A rare celestial event was captured by NASA's Chandra X-ray Observatory as Titan -- Saturn's largest moon and the only moon in the Solar System with a thick atmosphere -- crossed in front of the X-ray bright Crab Nebula. The X-ray shadow cast by Titan allowed astronomers to make the first X-ray measurement of the extent of its atmosphere. On January 5, 2003, Titan transited the Crab Nebula, the remnant of a supernova explosion that was observed to occur in the year 1054. Although Saturn and Titan pass within a few degrees of the Crab Nebula every 30 years, they rarely pass directly in front of it. "This may have been the first transit of the Crab Nebula by Titan since the birth of the Crab Nebula," said Koji Mori of Pennsylvania State University in University Park, and lead author on an Astrophysical Journal paper describing these results. "The next similar conjunction will take place in the year 2267, so this was truly a once in a lifetime event." Animation of Titan's Shadow on Crab Nebula Animation of Titan's Shadow on Crab Nebula Chandra's observation revealed that the diameter of the X-ray shadow cast by Titan was larger than the diameter of its solid surface. The difference in diameters gives a measurement of about 550 miles (880 kilometers) for the height of the X-ray absorbing region of Titan's atmosphere. The extent of the upper atmosphere is consistent with, or slightly (10-15%) larger, than that implied by Voyager I observations made at radio, infrared, and ultraviolet wavelengths in 1980. "Saturn was about 5% closer to the Sun in 2003, so increased solar heating of Titan may account for some of this atmospheric expansion," said Hiroshi Tsunemi of Osaka University in Japan, one of the coauthors on the paper. The X-ray brightness and extent of the Crab Nebula made it possible to study the tiny X-ray shadow cast by Titan during its transit. By using Chandra to precisely track Titan's position, astronomers were able to measure a shadow one arcsecond in diameter, which corresponds to the size of a dime as viewed from about two and a half miles. Illustration of Crab, Titan's Shadow and Chandra Illustration of Crab, Titan's Shadow and Chandra Unlike almost all of Chandra's images which are made by focusing X-ray emission from cosmic sources, Titan's X-ray shadow image was produced in a manner similar to a medical X-ray. That is, an X-ray source (the Crab Nebula) is used to make a shadow image (Titan and its atmosphere) that is recorded on film (Chandra's ACIS detector). Titan's atmosphere, which is about 95% nitrogen and 5% methane, has a pressure near the surface that is one and a half times the Earth's sea level pressure. Voyager I spacecraft measured the structure of Titan's atmosphere at heights below about 300 miles (500 kilometers), and above 600 miles (1000 kilometers). Until the Chandra observations, however, no measurements existed at heights in the range between 300 and 600 miles. Understanding the extent of Titan's atmosphere is important for the planners of the Cassini-Huygens mission. The Cassini-Huygens spacecraft will reach Saturn in July of this year to begin a four-year tour of Saturn, its rings and its moons. The tour will include close flybys of Titan that will take Cassini as close as 600 miles, and the launching of the Huygens probe that will land on Titan's surface. Chandra's X-ray Shadow of Titan Chandra's X-ray Shadow of Titan "If Titan's atmosphere has really expanded, the trajectory may have to be changed." said Tsunemi. The paper on these results has been accepted and is expected to appear in a June 2004 issue of The Astrophysical Journal. Other members of the research team were Haroyoski Katayama (Osaka University), David Burrows and Gordon Garmine (Penn State University), and Albert Metzger (JPL). Chandra observed Titan from 9:04 to 18:46 UT on January 5, 2003, using its Advanced CCD Imaging Spectrometer instrument. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the Office of Space Science, NASA Headquarters,

2004-05-01

441

Fillability of Thin-Wall Steel Castings  

SciTech Connect

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.

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

2002-07-30

442

Über die Bedeutung der Graphologie für die gerichtsärztliche Begutachtung  

Microsoft Academic Search

Zusammenfassung  \\u000a \\u000a \\u000a \\u000a 1. \\u000a \\u000a Die Graphologie ist eine Wissenschaft, die für charakterologische Behauptungen eine objektiv faßbare Grundlage bietet.\\u000a \\u000a \\u000a \\u000a \\u000a 2. \\u000a \\u000a Gegenüber der Beobachtung und Psychoanalyse bietet die Graphologie den Vorteil, daß sie unter völliger Wahrung der Integrität\\u000a des Patienten sehr viel schneller zum Ziele führt, auch wenn durch Unechtheit oder Verschlossenheit eine Erschwerung vorliegt.\\u000a \\u000a \\u000a \\u000a \\u000a 3. \\u000a \\u000a Die Graphologie ist eine Wissenschaft, deren sich der

A. Jores

1927-01-01

443

Die Frequenz, die wichtigste Eigenschaft des Augenzitterns der Bergleute  

Microsoft Academic Search

Von 1914–1950 ist die Frequenz im Hellen im Durchschnitt um 30 Schwingungen in der Minute gestiegen. Diese Zunahme ist größer als der Unterschied zwischen der Hell- und Dunkelfrequenz, der im Durchschnitt höchstens 17 Schwingungen beträgt.

J. Ohm

1952-01-01

444

CTD019Hickey, W8201_casts 19-22 Hickey, W8201_casts 19-22, page 1  

E-print Network

CTD019Hickey, W8201_casts 19-22 Hickey, W8201_casts 19-22, page 1 #12;CTD019Hickey, W8201_casts 19-22 Hickey, W8201_casts 19-22, page 2 #12;CTD019Hickey, W8201_casts 19-22 Hickey, W8201_casts 19-22, page 3 #12;CTD019Hickey, W8201_casts 19-22 Hickey, W8201_casts 19-22, page 4 #12;CTD019Hickey, W8201_casts 19

Hickey, Barbara

445

CTD021Hickey, W8101_casts 21-23 Hickey, W8101_casts 21-23, page 1  

E-print Network

CTD021Hickey, W8101_casts 21-23 Hickey, W8101_casts 21-23, page 1 #12;CTD021Hickey, W8101_casts 21-23 Hickey, W8101_casts 21-23, page 2 #12;CTD021Hickey, W8101_casts 21-23 Hickey, W8101_casts 21-23, page 3 #12;CTD021Hickey, W8101_casts 21-23 Hickey, W8101_casts 21-23, page 4 #12;CTD021Hickey, W8101_casts 21

Hickey, Barbara

446

CTD023Hickey, W8201_casts 23-25 Hickey, W8201_casts 23-25, page 1  

E-print Network

CTD023Hickey, W8201_casts 23-25 Hickey, W8201_casts 23-25, page 1 #12;CTD023Hickey, W8201_casts 23-25 Hickey, W8201_casts 23-25, page 2 #12;CTD023Hickey, W8201_casts 23-25 Hickey, W8201_casts 23-25, page 3 #12;CTD023Hickey, W8201_casts 23-25 Hickey, W8201_casts 23-25, page 4 #12;CTD023Hickey, W8201_casts 23

Hickey, Barbara

447

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

PubMed

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

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

2008-02-01

448

Yield improvement and defect reduction in steel casting  

SciTech Connect

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.

Kent Carlson

2004-03-16

449

Casting Castings: A Classroom Hands-on Activity  

NSDL National Science Digital Library

This learning activity will provide a useful technique for students to learn casting concepts. The class will be allowed a hands-on experience with casting. Students will make their own fishing sinkers. The lesson plan document includes step by step instructions for the lesson along with photographs.This activity would be appropriate for high school and college level students. The lesson should take about one hour of class time. This document will serve as a framework for instructors and may be downloaded in PDF format.

Johnson, Craig

450

Microstructure control during twin roll casting of an AZ31 magnesium alloy  

NASA Astrophysics Data System (ADS)

The existing twin roll casting technique for magnesium alloys suffers heterogeneity in both microstructure and chemistry and downstream processing is required to improve the strip quality, resulting in cost rise. In the present work, twin roll casting was carried out using an AZ31 magnesium alloy, with the application of intensive shearing melt conditioning prior to casting. The effect of process parameters such as pouring temperature and casting speed on microstructure control during casting and subsequent downstream processing was studied. Experimental results showed that the melt conditioning treatment allowed the production of AZ31 strips with uniform and refined microstructure free of centreline segregations. It was also shown that an optimized combination of pouring temperature and casting speed, in conjunction with a strip thickness control operation, resulted in uniformly distributed stored energies due to enhanced plastic deformation, which promoted recrystallization during casting and subsequent heat treatment. Strips prepared by twin roll casting and homogenization developed similar microstructural features to those prepared by twin roll casting followed by lengthy downstream processing by homogenization, hot rolling and annealing and displayed a weaker basal texture, exhibiting a potentially better formability.

Huang, Y.; Bayandorian, I.; Fan, Z.

2012-01-01

451

Texturing polymer surfaces by transfer casting. [cardiovascular prosthesis  

NASA Technical Reports Server (NTRS)

A technique for fabricating textured surfaces on polymers without altering their surface chemistries is described. A surface of a fluorocarbon polymer is exposed to a beam of ions to texture it. The polymer which is to be surface-roughened is then cast over the textured surface of the fluorocarbon polymer. After curing, the cast polymer is peeled off the textured fluorocarbon polymer, and the peeled off surface has negative replica of the textured surface. The microscopic surface texture provides large surface areas for adhesive bonding. In cardiovascular prosthesis applications the surfaces are relied on for the development of a thin adherent well nourished thrombus.

Banks, B. A.; Weigand, A. J.; Sovey, J. S. (inventors)

1982-01-01

452

Tape-cast sensors and method of making  

DOEpatents

A method of making electrochemical sensors in which an electrolyte material is cast into a tape. Prefabricated electrodes are then partially embedded between two wet layers of the electrolyte tape to form a green sensor, and the green sensor is then heated to sinter the electrolyte tape around the electrodes. The resulting sensors can be used in applications such as, but not limited to, combustion control, environmental monitoring, and explosive detection. A electrochemical sensor formed by the tape-casting method is also disclosed.

Mukundan, Rangachary (Santa Fe, NM); Brosha, Eric L. (Los Alamos, NM); Garzon, Fernando H. (Santa Fe, NM)

2009-08-18

453

PostCast Server Free Edition 2.6  

NSDL National Science Digital Library

Some users may find the need to send a significant number of emails at a time, and the free edition version of PostCast Server may be just the program to help accomplish this. This application allows users to deliver up to 50 messages at a time, and also increases the privacy of outgoing emails as well. Also, this same program may be used to send out electronic newsletters and other such notifications. This version of PostCast Server is compatible with all operating systems running Windows 95 and higher.

454

Three-dimensional assessment of dental casts' occlusal surfaces using two impression materials.  

PubMed

The aim of this study was to assess by means of a three-dimensional computed tomography scanning system the occlusal surface characteristics of dental casts made using two different impression materials. Alginate and polyvinyl siloxane impressions were taken of 20 dental students resulting in 40 dental casts. The casts were paired for each student separately so that each pair consisted of an alginate poured cast and a polyvinyl siloxane poured out cast. The casts were scanned using FlashCT scanner and for each cast, a three-dimensional digital image was obtained. The digitized casts were processed using the three-dimensional imaging software Geomagic Studio 9. A total of 464 paired teeth were digitally separated and superimposed. For each tooth, two measurements were obtained corresponding to the two different impression materials used. The two sets of volumes for all digitally separated teeth were compared and analysed using the Wilcoxon signed test. Larger volume measurements were obtained for teeth separated from alginate poured out casts than from their corresponding ones from polyvinyl siloxane casts (P = 0.005). When the teeth were divided into the groups of incisors, canines and premolars/molars, only the last one exhibited significant difference (P = 0.00). The mean difference between the volumes measured for all 464 teeth separated was 0.041 mm(3) (+/-0.33). The occlusal surfaces of teeth appear differently in dental casts depending on the impression materials used. Impressions of dental casts should be utilized with caution in relation to their research application and in reference with dental wear studies. PMID:18482343

Tarawneh, F M; Panos, P G; Athanasiou, A E

2008-11-01

455

Strain Rate Dependency of Bronze Metal Matrix Composite Mechanical Properties as a Function of Casting Technique  

NASA Astrophysics Data System (ADS)

Strain rate dependency of mechanical properties of tungsten carbide (WC)-filled bronze castings fabricated by centrifugal and sedimentation-casting techniques are examined, in this study. Both casting techniques are an attempt to produce a functionally graded material with high wear resistance at a chosen surface. Potential applications of such materials include shaft bushings, electrical contact surfaces, and brake rotors. Knowledge of strain rate-dependent mechanical properties is recommended for predicting component response due to dynamic loading or impact events. A brief overview of the casting techniques for the materials considered in this study is followed by an explanation of the test matrix and testing techniques. Hardness testing, density measurement, and determination of the volume fraction of WC particles are performed throughout the castings using both image analysis and optical microscopy. The effects of particle filling on mechanical properties are first evaluated through a microhardness survey of the castings. The volume fraction of WC particles is validated using a thorough density survey and a rule-of-mixtures model. Split Hopkinson Pressure Bar (SHPB) testing of various volume fraction specimens is conducted to determine strain dependence of mechanical properties and to compare the process-property relationships between the two casting techniques. The baseline performances of C95400 bronze are provided for comparison. The results show that the addition of WC particles improves microhardness significantly for the centrifugally cast specimens, and, to a lesser extent, in the sedimentation-cast specimens, largely because the WC particles are more concentrated as a result of the centrifugal-casting process. Both metal matrix composites (MMCs) demonstrate strain rate dependency, with sedimentation casting having a greater, but variable, effects on material response. This difference is attributed to legacy effects from the casting process, namely, porosity and localized WC particle grouping.

Brown, Lloyd; Joyce, Peter; Radice, Joshua; Gregorian, Dro; Gobble, Michael

2012-07-01

456

Marginal reservoirs for multiunit castings.  

PubMed

This study measured the distortion of one-piece base metal four-unit fixed partial dentures and recorded the effect of positioning "marginal reservoirs" on the wax patterns. Standard wax patterns were made in a special three-piece stainless steel mold. Twenty anterior prostheses were cast: 10 for the experimental group and 10 for the control group. The prostheses were cast in a nickel-chromium alloy and were measured with a traveling microscope with a micrometer scale. Premarked points were designated on gingivoaxial line angles for buccolingual and mesiodistal distances and diameters to record marginal discrepancies of specimens with or without marginal reservoirs. Castings with marginal reservoirs distorted significantly less than did the control fixed partial dentures. PMID:7568745

Omurtay, S; Aslan, Y

1995-04-01

457

CAST results and Axion review  

E-print Network

We present results from the CERN Axion Solar Telescope (CAST) and the Axion Dark Matter eXperiment (ADMX), together with a brief review on prospects on Axion searches with a variety of experimental techniques. CAST has explored masses up to 0.64 eV setting the most stringent limit on the axion-photon coupling, apart for the micro-eV region where ADMX is the most competitive experiment. CAST is aiming at surpassing the 1eV WMAP upper limit and possibly revisiting the operation in vacuum with extra sensitive X-ray detectors, while ADMX, using improved extra sensitive SQUID amplifiers will explore the micro-eV mass range.

T. Geralis; for the CAST collaboration

2009-05-26

458

Die fermentative Spaltung des Acetylcholins  

Microsoft Academic Search

Zusammenfassung Es wird eine neue Methode zum Nachweis des Fermentes, das Acetylcholin in Cholin und Essigsäure hydrolysiert, die Cholinesterase, beschrieben. Das Verfahren ist nach derWarburgschen Methode aufgebaut.

R. Ammon

1934-01-01

459

UNIVERSIT DE GENVE Dies Academicus  

E-print Network

Dufour, Auditoire Piaget Palmarès de l'année civile 1999 #12;Programme officiel de la journée du Dies connaissance Allocution de Monsieur Jean-Luc FALCONE Membre du Conseil de l'Université Représentant des

Loewith, Robbie

460

Development and Demonstration of Adanced Tooling Alloys for Molds and Dies  

SciTech Connect

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.

Kevin M. McHugh; Enrique J. Lavernia

2006-01-01

461

Feasibility Study for Casting of High Temperature Refractory Superalloy Composites  

NASA Technical Reports Server (NTRS)

Abstract This study investigated the feasibility of using conventional casting technique to fabricate refractory wires reinforced superalloy composites. These composites were being developed for advanced rocket engine turbine blades and other high temperature applications operating up to 2000 F. Several types of refractory metal wires such as W- Th, W-Re, Mo-Hf-C and W-HF-C reinforced waspaloy were experimentally cast and heat treated at 2000 F up to 48 hrs. Scanning electron microscope analysis was conducted in regions adjacent to the wire-matrix interface to determine the reaction zone and chemical compatibility resulting from material interdiffusion. It was concluded that fabrication using conventional casting may be feasible because the wire-matrix reaction zone thickness was comparable to similar composites produced by arc-sprayed monotape with hot isostatic pressing technique, Moreover, it was also found that the chemical compatibility could be improved significantly through a slight modification of the superalloy matrix compositions.

Lee, Jonathan A.

1998-01-01

462

Salicylatreiche Weiden für die Arzneimittelherstellung  

Microsoft Academic Search

Zusammenfassung  Die Verwendung eines möglichst salicylatreichen Ausgangsmaterials für die Herstellung von Phytopharmaka aus Weidenrinde ist\\u000a für eine ökonomische Arzneimittelherstellung notwendig. Nur so können günstige, pflanzliche Produkte auf den Markt gelangen,\\u000a welche von der Bevölkerung käuflich erworben werden, um fieberhafte Erkrankungen, Rheuma oder Kopfschmerzen behandeln zu können.\\u000a Um geeignetes Rindenmaterial zu finden, wurden Klone von den drei Weidenarten Salix daphnoides, Salix pentandra

Nadja Förster; Christian Ulrichs; Matthias Zander; Ralf Kätzel; Inga Mewis

2009-01-01

463

Destination Disney: Die japanischen Erfahrungen  

Microsoft Academic Search

Die Präsenz Japans auf dem internationalen Markt kultureller Produkte ist unübersehbar. Mangas und Anime finden weltweit begeisterte\\u000a Leser und Zuschauer. Die Pokémon-Zeichentrickserie erreichte beispielsweise in Deutschland über 70% der fernsehenden Kinder.\\u000a Der „Geist“ Japans mutiert in den Labors von Kosmetikherstellern und den Werkstätten von Innenausstattern zum Lebensstilemblem\\u000a und Ethno-Accessoire eines vorwiegend westlichen Publikums. Kaum ein Einkaufszentrum hierzulande und anderswo kommt

Ute Hoffmann

464

Microstructure of Al–Si–Mg alloy processed by rotary-die equal channel angular pressing  

Microsoft Academic Search

New rotary-die ECAP (RD-ECAP) was applied to a commercial Al–Si–Mg (AC4C) alloy to improve the ductility, and the microstructural developments and mechanical properties of ECAPed specimens were investigated. The as-cast Al alloy was used after machining to a cylindrical shape. ECAP was performed at 543, 603 and 673 K. The microstructure changes of samples were examined. The Vickers microhardness was

Jin-Chun Kim; Yoshinori Nishida; H Arima; Teiichi Ando

2003-01-01

465

Casting propellant in rocket engine  

NASA Technical Reports Server (NTRS)

A method is described for casting a solid propellant in the casing of a rocket engine having a continuous wall with a single opening which is formed by leaves of a material which melt at a temperature of the propellant and with curved edges concentric to the curvature of the spherical casing. The leaves are inserted into the spherical casing through the opening forming a core having a greater width than the width of the single opening and with curved peripheral edges. The cast propellant forms a solid mass and then heated to melt the leaves and provide a central opening with radial projecting flutes.

Roach, J. E.; Froehling, S. C. (inventors)

1976-01-01

466

Effect of severe plastic deformation on tensile properties of a cast Al–11 mass% Si alloy  

Microsoft Academic Search

Up to now, investigations for the effect of the severe plastic deformation on mechanical properties of the processed materials are not enough. In the present work, tensile properties of a cast Al–11mass% Si alloy processed by rotary-die equal-channel angular pressing (RD-ECAP) with 4–32 passes were investigated at room temperature. Elongation to failure significantly increased with the number of RD-ECAP passes

Aibin Ma; Naobumi Saito; Makoto Takagi; Yoshinori Nishida; Hiroyuki Iwata; Kazutaka Suzuki; Ichinori Shigematsu; Akira Watazu

2005-01-01

467

The effects of sprue design on the roughness and porosity of titanium castings  

Microsoft Academic Search

Purpose. This study measured the effects of the sprue number and position on the roughness and porosity of cast titanium crowns.Material and methods. Twenty-four complete veneer crown wax patterns were fabricated on a stainless steel die with a 30-degree bevel finish line. Twelve wax patterns were sprued with one 8-gauge wax sprue and the remaining 12 were double sprued. All

Daniel Chan; Villa Guillory; Ronald Blackman; Kwok-hung Chung

1997-01-01

468

Casting behavior of titanium alloys in a centrifugal casting machine.  

PubMed

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

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

2003-05-01

469

Cast-a-Box: Casting Conditions and Macroporosity  

NSDL National Science Digital Library

An illustration of three-dimensional finite difference simulation of heat conduction with phase change and complex boundary conditions, this requires students to adjust boundary conditions to make the top surface of a regular hexahedral "casting" to freeze last, eliminating macroporosity.

Powell, Adam C., IV

2004-08-24

470

Initial solidification phenomena: Factors affecting heat transfer in strip casting  

NASA Astrophysics Data System (ADS)

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 by increasing the critical undercooling, which in turns can be changed by changing the composition of the coating applied on the roll surface; this increase is significant when casting thicknesses are small (less than 1 mm). Finally, a procedure, based on Scheill's method, vaporization and liquation, to predict the composition of films depositing naturally during solidification, starting from the steel composition, is proposed.

Nolli, Paolo

471

INTERIOR VIEW WITH CASTING MACHINE COOLING A 20' IRON PIPE ...  

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

INTERIOR VIEW WITH CASTING MACHINE COOLING A 20' IRON PIPE PRIOR TO EXTRACTION FROM CASTING MACHINE. - McWane Cast Iron Pipe Company, Pipe Casting Area, 1201 Vanderbilt Road, Birmingham, Jefferson County, AL

472

INTERIOR VIEW WITH CASTING MACHINE AND A 4' DUCTILE IRON ...  

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

INTERIOR VIEW WITH CASTING MACHINE AND A 4' DUCTILE IRON PIPE BEING CENTRIFUGALLY CAST, AS OPERATOR WATCHES TO ENSURE QUALITY. - McWane Cast Iron Pipe Company, Pipe Casting Area, 1201 Vanderbilt Road, Birmingham, Jefferson County, AL

473

INTERIOR VIEW WITH CASTING MACHINE AND A 4" DUCTILE IRON ...  

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

INTERIOR VIEW WITH CASTING MACHINE AND A 4" DUCTILE IRON PIPE BEING EXTRACTED FROM CASTING MACHINE - McWane Cast Iron Pipe Company, Pipe Casting Area, 1201 Vanderbilt Road, Birmingham, Jefferson County, AL

474

INTERIOR VIEW OF CASTING MACHINE WITH 4' DUCTILE IRON PIPE ...  

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

INTERIOR VIEW OF CASTING MACHINE WITH 4' DUCTILE IRON PIPE BEING WEIGHED ON SCALES AT CASTING MACHINE. - McWane Cast Iron Pipe Company, Pipe Casting Area, 1201 Vanderbilt Road, Birmingham, Jefferson County, AL

475

INTERIOR VIEW, LOOKING NORTH, WITH CASTING SUPERINTENDENT OVERSEEING TRANSFER OF ...  

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

INTERIOR VIEW, LOOKING NORTH, WITH CASTING SUPERINTENDENT OVERSEEING TRANSFER OF MOLTEN METAL TO A CASTING MACHINE. - McWane Cast Iron Pipe Company, Pipe Casting Area, 1201 Vanderbilt Road, Birmingham, Jefferson County, AL

476

Mundrabilla: A Microgravity Casting  

NASA Astrophysics Data System (ADS)

The name "Mundrabilla" is applied to two nickel-iron meteorite masses (combined mass over 22,700 kg), which apparently were a single mass before atmospheric entry [1]. A medium octahedrite, Mundrabilla exhibits the microstructural features common to other nickel-iron meteorites such as Widmanstatten structure and troilite; however, its macrostructure is anything but common. Described by Buchwald as "anomalous" [1], Mundrabilla's macrostructural morphology is characterized by strikingly prominent, rounded Widmanstatten areas separated by regions of sulfur segregation (Fig. 1). While microstructural development of a metal can reflect both solidification and solid state reactions, macrostructural features are determined during solidification. Thus, a typical metallurgist, unfamiliar with microgravity solidification, might describe Mundrabilla's macrostructure as an "anomalous" casting. Those familiar with microgravity solidification might characterize Mundrabilla's macrostructural features as due to solidification of two immiscible liquids [2]--one rich in nickel-iron, the other rich in sulfur. Combining these observations, Mundrabilla's macrostructural features are consistent with that of a liquid mass solidified under microgravity conditions [3,4]. Since nickel-iron meteorite cooling rates often serve as the foundation for assumptions about the formation of solar system bodies, information on the solidification time for the Mundrabilla mass may give additional insights. How long did it take for Mundrabilla, with a minimum "as received" mass of approximately 22,700 kg to solidify? Because Mundrabilla's mass before atmospheric entry is unknown, we take as an upper boundary a mass of 4.1 x 10^15kg. These masses, assumed spherical, range in diameter between 1.8 meters and 10 kilometers, respectively. Mundrabilla can be idealized as a pure iron liquid mass cooling from the melting point of pure iron (1535C) by radiation into space at absolute zero. The latent heat of transformation for iron is used to calculate "excess temperature," i.e., the amount the mass temperature can be raised due to recalescence. Solidification is considered complete when the center of the mass is solid. Fig. 2, is a plot of the solidification times for an iron mass in the range 1.8 meters to 10 kilometers in diameter. At the lower bound, solidification time is about 1.6 hours; at the upper bound, solidification time is on the order of 3,400 years. References: [1] Buchwald V. F. (1975) Handbook of Iron Meteorites, University of California, Berkeley. [2] Carlberg T. and Fredriksson H. (1980) Metallurgical Transactions A, 11A, 1665-1676. [3] Budka P. Z. (1988) Metallurgical Transactions A, 19A, 1919-1923. [4] Budka P. Z. (1988) J. Metals, 40, 9, 6-9. Fig. 1, which appears here in the hard copy, shows Mundrabilla--a scale in inches. Figure 2, which appears here in the hard copy, shows solidification time vs. diameter.

Budka, P. Z.; Viertl, J. R. M.

1993-07-01

477

Integrally cored ceramic investment casting mold fabricated by ceramic stereolithography  

NASA Astrophysics Data System (ADS)

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 sil