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1

Die Casting.  

National Technical Information Service (NTIS)

Contents: Mechanical properties of creep resistant zinc die casting alloys; Studies on a gravity die cast zinc base alloy; Parashot system for turbulence-free injection of metal; Zinc--the versatile metal; Prevention of metal dribble on hot chamber die ca...

1977-01-01

2

Die Casting.  

National Technical Information Service (NTIS)

Contents: Recording technical information in pressure diecasting; Influence of copper addition on the dendritic structure of ILZRO-12; Graphite innoculated alloys for pressure die casting; Zinc--The versatile metal; Removal of scales from die cooling chan...

1978-01-01

3

Application of mold filling simulation to die casting processes  

SciTech Connect

Recently the authors find many reports on mold filling simulation and the related subjects. Using a general use computer code FLOW-3D, they research the practical application of mold filling simulation to die casting processes. The paper describes the result of this application. They compare the results of a water model experiment for die castings with that of the simulation. They determine the analysis conditions which cause the same flow patterns. To estimate the casting defects from the conditions, they compare the casting by a test die with that of the simulation. The application of the analysis model to a casting of air conditioner compressor proves practically useful by measuring amount of gases contained in the die castings.

Masuda, Eiji; Itoh, Isao; Haraguchi, Kenta [Honda Engineering Co., Ltd., Tochigi (Japan). Tochigi Research Center

1995-12-31

4

Magnesium die casting properties  

SciTech Connect

Numerous innovative applications of magnesium alloy die castings have recently been introduced by the automotive industry. This is the result of dedicated long-term development involving end users, die casters, and equipment and material suppliers. It is realized that superior product performance can only by obtained by fully exploiting the synergy of optimum design, processing route, and material selection. A particularly good example is provided by the rapid growth of magnesium die casting applications for safety parts, requiring high fracture toughness. In such applications, the favorable intrinsic properties of magnesium die casting alloys have been exploited to an extent which was formerly not believed possible. Introduction of new alloys such as AM50 has further expanded the range of properties attainable. Standard references on alloy properties do not reflect these developments, and there is a strong need for updated information. These data, reflecting recent advances in alloy chemistry and die casting technology, should be more current than those available in most sources of physical and mechanical properties.

NONE

1995-08-01

5

Vacuum Die Casting of Silicon Sheet for Photovoltaic Applications  

NASA Technical Reports Server (NTRS)

The development of a vacuum die-casting process for producing silicon sheet suitable for photovoltaic cells with a terrestrial efficiency greater than 12 percent and having the potential to be scaled for large quantity production is considered. The initial approach includes: (1) obtaining mechanical design parameters by using boron nitride, which has been shown to non-wetting to silicon; (2) optimizing silicon nitride material composition and coatings by sessile drop experiments; (3) testing effectiveness of fluoride salt interfacial media with a graphite mold; and (4) testing the effect of surface finish using both boron nitride and graphite. When the material and mechanical boundary conditions are established, a finalized version of the prototype assembly will be constructed and the casting variables determined.

1979-01-01

6

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

7

Application of a tungsten/tungsten-carbide film to H-13 casting dies by plasma assisted deposition  

SciTech Connect

Die casting is used extensively to produce Al, Mg and Zn alloy parts. H-13, a widely used die material, is a medium carbon steel alloy with Cr, Mo, and Si. A problem with die casting is soldering, thermal fatigue cracking, and carbon buildup which cause degradation of the casting. Application of a metallic coating to the die has been shown to increase the resistance to thermal fatigue cracking. In this study, a tungsten/tungsten carbide thin film was deposited on a casting die of H-13 die steel by a two step Plasma Source Ion Enhanced Deposition process using an argon and methane plasmas. The film was characterized using Auger Electron Spectroscopy, Scanning Electron Microscopy and Electron Dispersive Spectroscopy. The die and representative castings (from regular intervals during the lifetime of the die) were examined for evidence of soldering, thermal fatigue cracking and carbon buildup.

Horswill, N.; Jetzer, W.; Fetherston, P.; Conrad, J.R. [Univ. of Wisconsin, Madison, WI (United States)

1995-12-31

8

Thermo fatigue cracking of die casting dies  

Microsoft Academic Search

The investigation of aluminium alloy die casting die failures was done with the emphasis on thermal cracks. The aim of the study was to prolog the in-service die life by cladding with maraging steels, which would be economically beneficial. A vast analysis of thermal fatigue cracks in aluminium alloy die casting is done. Immersion test apparatus was developed, which enables

D. Klob?ar; L. Kosec; B. Kosec; J. Tuek

2010-01-01

9

Design for die casting  

Microsoft Academic Search

The purpose of this research was to establish methods and a system for transforming finished (machined) part designs into shapes that are die castable. The major contribution from this work is a consistent and systematic method of analysing the shape of die castings. This research is necessary because computer-aided design\\/manufacturing\\/engineering (CAD\\/CAM\\/CAE) systems are only loosely coupled, making manufacturability analysis very

S. Y. LIOU; R. A. MILLER

1991-01-01

10

Application of hard coatings in aluminium die casting soldering, erosion and thermal fatigue behaviour  

Microsoft Academic Search

In aluminium die casting, tools are exposed to erosion, corrosion and soldering due to the frequent contact of the tool surface to the casting alloy, to heat checking and gross cracking due to thermal fatigue and to oxidation due to high pouring temperatures. The gradual destruction of die surfaces during service decreases casting piece quality and limits die lifetime. Hard

C Mitterer; F Holler; F stel; D Heim

2000-01-01

11

Fatigue properties of die cast zinc alloys for automotive lock applications  

SciTech Connect

During the 1970s many automotive lock systems were converted from zinc die casting alloys to engineering plastics for reasons of weight and cost. Recent increases in requirements for precision and security have caused automotive and other lock designers to reconsider zinc alloy die-castings for these applications. To enable this, there is a need for mechanical property data comparable to that of the plastics materials used in these applications. In this work, rotary bending fatigue tests were performed on Alloys 3, 5, ZA-8 and AcuZinc 5 using an R.R. Moore fatigue machine. Testing was performed at 30 Hz and was stopped at 1x107 cycles. The fatigue limit results were compared to data reported in the literature for higher number of cycles and faster rotations.

Schrems, Karol K.; Dogan, Omer N.; Goodwin, F.E. (International Lead and Zinc Research Organization, Research Triangle, NC)

2004-06-01

12

Sputtered protective coatings for die casting dies  

SciTech Connect

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.

1981-01-01

13

Die Soldering in Aluminium Die Casting.  

National Technical Information Service (NTIS)

Two types of tests, dipping tests and dip-coating tests were carried out on small steel cylinders using pure aluminum and 380 alloy to investigate the mechanism of die soldering during aluminum die casting. Optical and scanning electron microscopy were us...

Q. Han, E. A. Kenik, S. Viswanathan

2000-01-01

14

Die Soldering in Aluminium Die Casting  

Microsoft Academic Search

Two types of tests, dipping tests and dip-coating tests were carried out on small steel cylinders using pure aluminum and 380 alloy to investigate the mechanism of die soldering during aluminum die casting. Optical and scanning electron microscopy were used to study the morphology and composition of the phases formed during soldering. A soldering mechanism is postulated based on experimental

Q. Han; E. A. Kenik; S. Viswanathan

2000-01-01

15

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

16

A study of PVD coatings and die materials for extended die-casting die life  

Microsoft Academic Search

There have been some applications of PVD coatings to extend die-casting die life, mainly by reducing molten metal corrosion and erosion to the die. However, die steel heat checking (or thermal cycling induced cracking) resistance is affected significantly by the PVD coatings. This paper presents the results of a systematic study involving three H series and two maraging hot work

Yucong Wang

1997-01-01

17

Die Soldering in Aluminium Die Casting  

SciTech Connect

Two types of tests, dipping tests and dip-coating tests were carried out on small steel cylinders using pure aluminum and 380 alloy to investigate the mechanism of die soldering during aluminum die casting. Optical and scanning electron microscopy were used to study the morphology and composition of the phases formed during soldering. A soldering mechanism is postulated based on experimental observations. A soldering critical temperature is postulated at which iron begins to react with aluminum to form an aluminum-rich liquid phase and solid intermetallic compounds. When the temperature at the die surface is higher than this critical temperature, the aluminum-rich phase is liquid and joins the die with the casting during the subsequent solidification. The paper discusses the mechanism of soldering for the case of pure aluminum and 380 alloy casting in a steel mold, the factors that promote soldering, and the strength of the bond formed when soldering occurs. conditions, an aluminum-rich soldering layer may also form over the intermetallic layer. Although a significant amount of research has been conducted on the nature of these intermetallics, little is known about the conditions under which soldering occurs.

Han, Q.; Kenik, E.A.; Viswanathan, S.

2000-03-15

18

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

19

Thermal stresses in aluminium alloy die casting dies  

Microsoft Academic Search

The aim of this research is to analyze the influence of Aluminium Alloy die casting parameters, die material, and die geometry on in-service tool life. An innovative immersion testing apparatus is developed, at which Aluminium Alloy die casting is simulated. It enables controlled thermal fatigue cycling. Special specimens with different edge geometry and specimens with maraging steel welds deposited by

Damjan Klob?ar; Janez Tuek

2008-01-01

20

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

21

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

22

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

23

Die casting process optimization using Taguchi methods  

Microsoft Academic Search

This paper analyzes various significant process parameters of the die casting method of AlSi9Cu13 aluminum alloy. An attempt has been made to obtain optimal settings of the die casting parameters, in order to yield the optimum casting density of the AlSi9Cu13 aluminum alloy castings. The process parameters considered were: piston velocity (first and second stage), metal temperature, filling time and

G. P. Syrcos

2003-01-01

24

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

SciTech Connect

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 {alpha}-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 deg. 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, Yuecel [Materials Institute, Marmara Research Center, TUeBITAK, Kocaeli (Turkey); Birol, Feriha [R and D Center, ARCELIK, Tuzla, Istanbul (Turkey)

2007-04-07

25

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

26

Development of a non-intrusive heat transfer coefficient gauge and its application to high pressure die casting  

Microsoft Academic Search

A heat transfer coefficient gauge has been built, obeying particular rules in order to ensure the relevance and accuracy of the collected information. The gauge body is made out of the same materials as the die casting die (H13). It is equipped with six thermocouples located at different depths in the body and with a sapphire light pipe. The light

G. Dour; M. Dargusch; C. Davidson; A. Nef

2005-01-01

27

Modeling the Mechanical Performance of Die Casting Dies  

SciTech Connect

The following report covers work performed at Ohio State on modeling the mechanical performance of dies. The focus of the project was development and particularly verification of finite element techniques used to model and predict displacements and stresses in die casting dies. The work entails a major case study performed with and industrial partner on a production die and laboratory experiments performed at Ohio State.

R. Allen Miller

2004-02-27

28

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

29

Sputtered protective coatings for die casting dies  

NASA Technical Reports Server (NTRS)

Three experimental research designs investigating candidate materials and processes involved in protective die surface coating procedures by sputter deposition, using ion beam technologies, are discussed. Various pre-test results show that none of the coatings remained completely intact for 15,000 test cycles. The longest lifetime was observed for coatings such as tungsten, platinum, and molybdenum which reduced thermal fatigue, but exhibited oxidation and suppressed crack initiation only as long as the coating did not fracture. Final test results confirmed earlier findings and coatings with Pt and W proved to be the candidate materials to be used on a die surface to increase die life. In the W-coated specimens, which remained intact on the surface after thermal fatigue testing, no oxidation was found under the coating, although a few cracks formed on the surface where the coating broke down. Further research is planned.

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

1981-01-01

30

Formation of defect bands in high pressure die cast magnesium alloys  

Microsoft Academic Search

Die cast magnesium components are being increasingly used worldwide because of the excellent castability and properties that magnesium alloys offer. High pressure die casting of thin-walled components is particularly suitable because of the excellent flow characteristics of molten magnesium alloys. Typical automotive applications for thin-walled castings include components such as instrument panels, steering wheels, door frames and seat frames. These

A. K Dahle; S Sannes; D. H St. John; H Westengen

2001-01-01

31

Potential Magnesium Alloys for High Temperature Die Cast Automotive Applications: A Review  

Microsoft Academic Search

Magnesium, as a lightweight construction material, has rapidly grown its applications in the automotive industry since the early 1990s. To maximize the weight reduction of vehicles by lightweight magnesium alloys in the coming years, the use of newly developed high-temperature magnesium alloys is expected to increase significantly, particularly in the powertrain applications where the creep resistance is always required. This

Henry Hu; Alfred Yu; Naiyi Li; John E. Allison

2003-01-01

32

Metalcasting: Die Casting Copper Motor Rotors  

SciTech Connect

Decreased energy requirements, air emissions, production time, and operating costs are some of the benefits that will accrue to the metalcasting industry as result of this new die casting technique. This fact sheet provides the details of this exciting new process for fabricating copper motor rotors.

Recca, L.

1999-01-29

33

Fatigue of die cast zinc alloys  

SciTech Connect

The rotating bending fatigue limit of die cast zinc alloy 2, alloy 3, alloy 5, AcuZinc 5, and ZA-8 were determined as a part of an on-going program by ILZRO into the mechanical properties of die cast zinc. The stress-life (S-N) curves of alloys 3, 5, AcuZinc 5, and ZA-8 were determined previously. This presentation reports the results of the S-N curve for Alloy 2 and the calculated fatigue limits for all five alloys. During the previous stress-life testing, the samples were stopped at 10 million cycles and the fatigue limit for alloy 3, alloy 5, and AcuZinc 5 appeared to be higher and the fatigue limit for ZA-8 appeared to be lower than the values reported in the literature. This was further investigated in alloy 5 and ZA-8 by testing continuous cast bulk alloy 5 and ZA-8.

Schrems, K.K.; Dogan, O.N.; Goodwin, F.E. (International Lead Zinc Research Organization, Inc.)

2006-04-01

34

Computer modeling and prediction of thermal fatigue cracking in die-casting tooling  

Microsoft Academic Search

Thermal fatigue cracking is a major mode of failure of hot working tool steel dies in die-casting and forging applications. This results in huge loss owing to high cost of dies, downtime and die repair and replacement. The cracking initiates due to the large thermal shock experienced by the die surface when it is rapidly heated to 700C and then

A Srivastava; V Joshi; R Shivpuri

2004-01-01

35

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

36

Study on a CAD\\/CAE system of die casting  

Microsoft Academic Search

Increasing demans for premium quality, high productivity and cost-saving products provide powerful incentives to improve the way that die castings are made today. Research has shown that the fluid flow of the liquid metal and the temperature distribution of the dies and the die castings have a critical influence on the quality of the cast products, on the production rate

Zhang Weishan; Xiong Shoumei; Liu Baicheng

1997-01-01

37

Characterization of Spray Lubricants for the Die Casting Process  

SciTech Connect

During the die casting process, lubricants are sprayed in order to cool the dies and facilitate the ejection of the casting. The cooling effects of the die lubricant were investigated using Thermogravimetric analysis (TGA), heat flux sensors (HFS), and infrared imaging. The evolution of the heat flux and pictures taken using a high speed infrared camera revealed that lubricant application was a transient process. The short time response of the HFS allows the monitoring and data acquisition of the surface temperature and heat flux without additional data processing. A similar set of experiments was performed with deionized water in order to assess the lubricant effect. The high heat flux obtained at 300 C was attributed to the wetting and absorbant properties of the lubricant. Pictures of the spray cone and lubricant flow on the die were also used to explain the heat flux evolution.

Sabau, Adrian S [ORNL

2008-01-01

38

A runner-optimization design study of a die-casting die  

Microsoft Academic Search

Die casters usually carry out a die casting test before producing new castings. At the die-casting test stage, the runner part is always repeatedly corrected, which leads to a lengthened processing time and increased processing cost. In order to solve this problem, research studies of the runner and die body parts have been performed separately during the present experiments. For

C. C Tai; J. C Lin

1998-01-01

39

77 FR 6587 - PHB Die Casting a Subsidiary of PHB, Inc., Including On-Site Leased Workers From Career Concepts...  

Federal Register 2010, 2011, 2012, 2013

...Administration [TA-W-64,292] PHB Die Casting a Subsidiary of PHB, Inc., Including...applicable to workers of PHB Die Casting, a subsidiary of PHB, Inc...are engaged in the production of die castings. New information shows that...

2012-02-08

40

Improved die castings through plasma surface modification, improved sensors and die soldering prevention. Quarterly progress report 1, July 1--September 30, 1994  

SciTech Connect

This quarterly report covers activities of the Die Casting Research project during the period July 1, 1994 through September 30, 1994, at The Ohio State University. The objective of the Die Casting Research project is to enhance the competitiveness of the US die casting industry. To accomplish this objective, the Center for Die Casting at The Ohio State University shall perform tasks that focus on three general areas: the application of plasma surface modifications to aluminum and zinc casting dies; the development and evaluation of systems to monitor temperature, pressure, and gas content of die casting cavities; and the determination of causes of die soldering in zinc die castings. This quarterly report covers work on Task 2 -- Commercial Sensor Evaluation.

Mobley, C.; Brevick, J.

1994-10-17

41

Possibility of introducing laser surfacing into maintenance service of die-casting dies  

Microsoft Academic Search

The shape and manufacturing of tools for die casting of aluminium and magnesium alloys are usually extremely exacting and therefore very expensive. In a die-casting process, these tools are subjected to strong thermo-mechanical loads. From the economic point of view the operation life of dies is extremely important to the price of the castings. It has been proved that by

J. Grum; J. M. Slabe

2004-01-01

42

Case of temperature field and failure analysis of die-casting die  

Microsoft Academic Search

Purpose: Dies for aluminium alloys die-casting fail because of a great number of a different and simultaneously operating factors. Some of them may be controlled to some extent by the die-casting experts. Design\\/methodology\\/approach: In the experimental part of our work the failures on the working surface of the fixed half of the testing die for die-casting of aluminium alloys were

B. Kosec; G. Kosec

43

Vacuum assisted high pressure die casting of aluminium alloys  

Microsoft Academic Search

High pressure die castings usually contain gas porosity due mainly to the entrapment of air or gas in the melt during the very high speed injection of the molten metal into the cavity. In this paper, the advantages of using an evacuated die cavity during mould filling were evaluated. ASTM standard die casting tensile specimens of three Al alloys, Al5%Si,

X. P. Niu; B. H. Hu; I. Pinwill; H. Li

2000-01-01

44

Die-cast copper rotors for improved motor performance  

Microsoft Academic Search

Aluminum has been the common conductor material for the squirrel cage of the induction motor largely because of ease of manufacturing by pressure die casting. Short die life in die casting the higher melting copper resulting in high production cost has prevented the copper rotor from attaining a place in integral horsepower motors. Because of its higher electrical conductivity, copper

John G. Cowie; D. T. Brender

2003-01-01

45

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

46

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

47

Effect of process parameters on porosity distributions in high-pressure die-cast AM50 Mg-alloy  

Microsoft Academic Search

High-pressure die-casting is the preferred manufacturing process for cast Mg-alloy components used for numerous applications. High-pressure die-cast components usually contain micro-porosity that adversely affects their mechanical properties. In this contribution, the effects of three important process parameters, gate velocity, intensification pressure, and melt temperature on the micro-porosity distributions in high-pressure die-cast AM50 Mg-alloy are quantitatively characterized. The amounts of total

S. G. Lee; A. M. Gokhale; G. R. Patel; M. Evans

2006-01-01

48

Copper die-cast rotor efficiency improvement and economic consideration  

Microsoft Academic Search

Significant motor efficiency improvement can be achieved by substituting aluminum with copper die-cast rotor in a squirrel cage induction motor. This paper summarizes the experiments conducted by Westinghouse Motor Company Canada Ltd. in our copper die-cast rotor induction motors project

SIAN LIE; CARLO DI PIETRO

1995-01-01

49

Segregation band formation in Al-Si die castings  

Microsoft Academic Search

Banded defects are often found in high-pressure die castings. These bands can contain segregation, porosity, and\\/or tears,\\u000a and changing casting conditions and alloy are known to change the position and make-up of the bands. Due to the complex, dynamic\\u000a nature of the high-pressure die-casting (HPDC) process, it is very difficult to study the effect of individual parameters\\u000a on band formation.

Christopher M. Gourlay; Arne K. Dahle; Hans I. Laukli

2004-01-01

50

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

51

Evaluation of a Heat Flux Sensor for Spray Cooling for the Die Casting Processes  

SciTech Connect

During the die casting process, lubricants are sprayed in order to cool the dies and facilitate the ejection of the casting. In this paper, a new technique for measuring the heat flux during lubricant application is evaluated. Data from experiments conducted using water spray are first presented. Water spray experiments were conducted for different initial plate temperatures. Measurements were conducted for the application of two different lubricants, of dilution ratios of 1/15 and 1/50 of lubricant in water. The measurement uncertainties were documented. The results show that the surface temperature decreases initially very fast. Numerical simulation results confirmed that the abrupt temperature drop is not an artifact but illustrates the thermal shock experienced by the dies during the initial stages of lubricant application. The lubricant experiments show that the sensor can be successfully used for testing die lubricants with typical dilution ratios encountered in the die casting process.

Sabau, Adrian S [ORNL; Wu, Zhuoxi [ORNL

2007-02-01

52

Performance enhancements of high-pressure die-casting die processed by biomimetic laser-remelting process  

Microsoft Academic Search

Die service life improvement is an important problem in high-pressure die-casting industry. Experiment results on die steel\\u000a shows that biomimetic laser-remelting process provides a promising method to improve the service life of die-casting die.\\u000a A casting with uneven wall thickness was selected and problems existing in die-casting production were analyzed. The corresponding\\u000a die-casting die was processed by biomimetic laser-remelting process.

Zhi-xin Jia; Ji-qiang Li; Li-Jun Liu; Hong Zhou

53

Aging of maraging steel welds during aluminium alloy die casting  

Microsoft Academic Search

The aim of this study is to evaluate precipitation annealing of 18% Ni maraging steel repair welds during aluminium die casting and to predict the prolonged in-service tool life. The emphasis of this study is the influence of post-weld precipitation annealing heat treatment and aluminium die casting thermal cycling on metallurgical and mechanical properties. A series of specimens of 1.2344

D. Klob?ar; J. Tuek; B. Taljat; L. Kosec; M. Pleterski

2008-01-01

54

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

55

Analysis of the mechanism of die soldering in aluminum die casting  

Microsoft Academic Search

A mechanism of soldering of an aluminum alloy die casting to a steel die is proposed. A soldering critical temperature is\\u000a postulated, at which iron begins to react with aluminum to form an aluminum-rich liquid phase and solid intermetallic compounds.\\u000a The liquid joins the die with the casting upon solidification. The critical temperature is determined by the elements in both

Q. Han; S. Viswanathan

2003-01-01

56

Formation and progression of die soldering during high pressure die casting  

Microsoft Academic Search

High pressure die casting experiments have been conducted and detailed metallurgical examination of the soldered samples was made to study the formation and early progression of die soldering. It was found that soldering formed initially with a build-up of cast alloy on the samples (named mechanical soldering). Two major build-up modes were identified. One was a sudden build-up of a

Z. W. Chen

2005-01-01

57

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

58

Evaluation of permanent die coatings to improve the wear resistance of die casting dies. Final project report, January 1, 1995--April 30, 1997.  

National Technical Information Service (NTIS)

Die Casting dies are subject to severe service conditions during the die casting operation. While these severe conditions are necessary to achieve high production rates, they cause the dies which are commonly made of H13 die steel, to suffer frequent fail...

R. Shivpuri

1997-01-01

59

Effect of Phase Pressure on Casting Properties in Cold Chamber Die Casting Process  

NASA Astrophysics Data System (ADS)

This paper focuses on the parametric optimization of process parameter in cold chamber die casting for an industrial component (crank case). Three controllable factors of the cold chamber die casting process (namely: 1st phase pressure, 2nd phase pressure and limit switch position) were studied at three levels each by Taguchi's parametric approach and single-response optimization was conducted to identify the main factor controlling surface hardness, weight of casting and dimensional accuracy (?d). Castings were produced using aluminium alloy at recommended parameters through cold chamber die casting process. Analysis shows that in cold chamber die casting process the percentage contribution of 1st phase pressure, limit switch position and 2nd phase pressure for surface hardness is 84.17, 11.43 and 1.93 % respectively. While in the case of weight of cast component, the contribution of limit switch position is 52.26 %, followed by 1st phase pressure and 2nd phase pressure 34.77 and 9.65 % respectively. Further for ?d, contribution of 1st phase pressure is 64.55 %, limit switch position 27.71 % and 2nd phase pressure contributes 4.87 %.

Singh, R.; Kapoor, R.

2013-04-01

60

Creep behavior of magnesium die-cast alloy ZA85  

Microsoft Academic Search

The compressive creep behavior of a magnesium die-cast alloy with 8 wt.% Zn and 5 wt.% Al was investigated. We argue that grain boundary sliding does not contribute to the deformation. Creep data and microstructural analysis strongly support dislocation creep, influenced by the formation and over-aging of precipitates, as the dominant mechanism.

M. Vogel; O. Kraft; E. Arzt

2003-01-01

61

Evaluation of permanent die coatings to improve the wear resistance of die casting dies. Final project report, January 1, 1995--April 30, 1997  

SciTech Connect

Die Casting dies are subject to severe service conditions during the die casting operation. While these severe conditions are necessary to achieve high production rates, they cause the dies which are commonly made of H13 die steel, to suffer frequent failures. The major die failure mechanisms are erosion or washout, Heat checking, soldering and corrosion. Due to their geometrical complexity, die casting dies are very expensive (some dies cost over a million dollars), and thus a large number of parts have to be produced by a die, to justify this cost and leverage the advantages of the die casting process (high production rates, low manpower costs). A potential increase in the die service life, thus has a significant impact on the economics of the die; casting operation. There are many ways to extend die life: developing new wear resistant die materials, developing new surface treatments including coatings, improving heat treatment of existing H13 dies, using better lubricants that can protect the die material, or modifying the die geometry and process parameters to reduce the intensity of wear. Of these the use of coatings to improve the wear resistance of the die surface has shown a lot of promise. Consequently, use of coatings in the die casting industry and their wide use to decrease die wear can improve significantly the productivity of shop operations resulting in large savings in material and energy usage.

Shivpuri, R.

1997-09-18

62

Metallographic assessment of Al-12Si high-pressure die casting escalator steps.  

PubMed

A microstructural characterization study was performed on high-pressure die cast specimens extracted from escalator steps manufactured from an Al-12 wt.% Si alloy designed for structural applications. Black and white, color light optical imaging and scanning electron microscopy techniques were used to conduct the microstructural analysis. Most regions in the samples studied contained globular-rosette primary ?-Al grains surrounded by an Al-Si eutectic aggregate, while primary dendritic ?-Al grains were present in the surface layer. This dendritic microstructure was observed in the regions where the melt did not impinge directly on the die surface during cavity filling. Consequently, microstructures in the surface layer were nonuniform. Utilizing physical metallurgy principles, these results were analyzed in terms of the applied pressure and filling velocity during high-pressure die casting. The effects of these parameters on solidification at different locations of the casting are discussed. PMID:24999947

Vander Voort, George Frederic; Surez-Pea, Beatriz; Asensio-Lozano, Juan

2014-10-01

63

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.

64

High-speed machining of cast iron and alloy steels for die and mold manufacturing  

E-print Network

High-speed machining of cast iron and alloy steels for die and mold manufacturing P. Fallbo?hmer, C of cast iron and alloy steels used in die and mold manufacturing. This work covers: (a) theoretical tool temperatures and stresses and for extending tool life. Along with machining of castings, die

Ozel, Tugrul

65

A neural network system for the prediction of process parameters in pressure die casting  

Microsoft Academic Search

In this work an artificial intelligent neural network system is developed to generate the process parameters for the pressure die casting process. The scope of this work includes analysing a physical model of the pressure die casting filling stage based on the governing equations of die cavity filling, and the collection of feasible casting data for the training of the

Prasad K. D. V. Yarlagadda; Eric Cheng Wei Chiang

1999-01-01

66

Die casting die deflections: Prediction and attenuation. Final report, July 1, 1995--September 30, 1997  

SciTech Connect

This report summarizes two years of research intended to develop methods to model and predict the deflection patterns in die casting dies. No comprehensive analysis of this type had previously been completed. The die casting process is complex and involves numerous mechanical and thermal phenomena that effect the mechanical behavior of the die. A critical activity in this work was sorting out and evaluating the relative contributions of the various mechanisms to die deflections. This evaluation was accomplished through a series of simple engineering analyses based primarily on the order of magnitude of the influence of each load considered on die deflections. A modeling approach incorporating commercially available finite element analysis software was developed and tested. The model evolved by testing simple models against more comprehensive models and against the limited experimental data that is available. The development of the modeling approach lead to consideration of the die casting machine in more detail than was originally anticipated. The machine is critical and cannot be ignored. A simplified model described as a spring/platen model was developed to account for the machine platens, tie bars, and toggles. The characteristics of this model are described and predictions based on this model are compared against full machine models and measured deflections of machine platens. Details of the modeling approach and the various case studies are provided in the report and in several publications that have resulted from the work.

Miller, R.A.; Ahuett-Garza, H.; Choudhury, A.K.; Dedhia, S.

1998-05-01

67

Laser beam welding of aluminum die casting with reduced pore formation  

SciTech Connect

Laser beam welding is already well treated within the laboratory, but there is still a minor industrial application because of the lack of reliability of the process due to violent fluctuations of the plasma formation above and melt flow turbulence around the welding key-hole. An even greater challenge is the welding of die cast aluminum since the high hydrogen content dissolved within the material during the casting process is responsible for a strong pore formation of the weld and a rather unsteady welding process. During the last 10 years, intensive research work has been executed by the research institute of the authors in order to increase the weldability of die-case aluminum by optimization of the casting process. The casting process has been optimized in such a way that as few gases as possible can penetrate into the castings. The porosity of the welds has been reduced to a level comparable to that of high-quality joints of wrought material. The weld quality achieved by electron beam welding is excellent. The range of possible welding speeds and the necessary laser power depending on the wall thickness and the chosen optical arrangement are quantified. Die casting of aluminum is a manufacturing operation of high productivity. However, it s not suited for production of hollow structures. A combination with a highly productive welding technique such as laser beam welding is now available, and one may expect it to be of reasonable economic benefit in the future.

Rehbein, D.H.; Decker, I.; Wohlfahrt, H.

1994-12-31

68

Corrosion behaviour of high pressure die-cast and semi-solid cast AZ91D alloys  

Microsoft Academic Search

The microstructure and the corrosion behaviour of high pressure die-cast and semi-solid cast AZ91D magnesium alloys have been investigated. Semi-solid processing leads to a structure with large rounded grains of a solid solution of magnesium (? phase) whereas die-cast alloys are more homogeneous. Electrochemical measurements, particularly with impedance spectroscopy, have shown that the semi-solid cast alloy possesses a corrosion rate

S Mathieu; C Rapin; J Hazan; P Steinmetz

2002-01-01

69

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

70

Corrosion fatigue of die-cast and extruded magnesium alloys  

Microsoft Academic Search

To study the fatigue life of die-cast and extruded AZ91D, AM50 and AZ31 magnesium alloys, corrosion fatigue tests were carried out using a rotating beam type fatigue machine. Corrosive environment (3.5% NaCl) significantly decreases fatigue life of alloys, especially for extruded alloys. The fatigue data at high stresses were analyzed using fitting equations. Extruded alloys show a higher sensitivity to

A Eliezer; E. M Gutman; E Abramov; Ya Unigovski

2001-01-01

71

Die casting research: Die cavity instrumentation. Final report, Tasks 2--5  

SciTech Connect

The primary objective of this project was to evaluate the performance characteristics and usefulness of near cavity temperature, liquid pressure, and gas flow rate sensors for improved monitoring and control of die casting processes. Three types of near cavity sensors were evaluated: a multi-thermocouple probe used for determining the surface and near-cavity thermal history of the die; a commercially available direct cavity pressure sensor for measuring the pressure history of the liquid and solidifying alloy in the die cavity; and a vent gas flow sensor for monitoring whether gas exits the cavity vent during cavity filling.

Mobley, C.E.; Brevick, J.

1997-12-31

72

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

73

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

74

Optimization of Gating System Design for Die Casting of Thin Magnesium Alloy-Based Multi-Cavity LCD Housings  

NASA Astrophysics Data System (ADS)

High-pressure die casting is the preferred process for manufacturing Mg-alloy components used for numerous applications. High-pressure die casting is suitable for mass production and has the advantage of also being suitable for accurately fashioning objects of complicated shapes. One disadvantage of high-speed die casting is the occurrence of defects such as shrinkage or air entrainment. Gating system design must be very effective in actual manufacturing facilities to avoid the occurrence of such defects. The objective of this study is to present a methodology for obtaining optimal designs of 4-cavity thin electronic component housings. The fluid behavior and amount of air entrainment caused by the overflows and air vent designs were analyzed using a computer fluid dynamics (CFD) simulator. The effectiveness of the proposed system was demonstrated through CFD simulations and experiments using an actual manufacturing process. Also, the effect of vacuum systems on the porosity and mechanical properties of the castings was studied. The volume of porosity in the casting was found to be significantly reduced using vacuum assistance during die casting. As a result, the tensile strength and the elongation of the die casting products are improved.

Lee, B. D.; Baek, U. H.; Han, J. W.

2012-09-01

75

Notched bar Izod impact properties of zinc die castings  

SciTech Connect

Notched bar Izod impact testing of zinc die cast Alloy 3, Alloy 5, ZA-8, and AcuZinc 5 was performed at five temperatures between -40\\mDC and room temperature in accordance with ASTM E23 for impact testing of metallic materials. A direct comparison between ASTM D256 for impact testing of plastics and ASTM E23 was performed using continuously cast zinc specimens of Alloy 5 and ZA-8 at -40\\mDC and room temperature. There are differences in sample sizes, impact velocity, and striker geometry between the two tests. Bulk zinc tested according to ASTM E23 resulted in higher impact energies at -40\\mDC and lower impact energies at room temperature then did the same alloys when tested according to ASTM D256.

Schrems, K.K.; Dogan, O.N.; Goodwin, F.E. (International Lead Zinc Research Organization, Inc.)

2007-03-01

76

The Effects of Externally Solidified Product on Wave Celerity and Quality of Die Cast Products  

SciTech Connect

The cold chamber die casting process is used to produce essentially all the die cast aluminum products and about 50% of the die cast magnesium products made today. Modeling of the cold chamber die casting process and metallographic observations of cold chamber die cast products indicate that typically 5 to 20% of the shot weight is solidified in the shot sleeve before or during cavity filling. The protion of the resulting die casting which is solidified in the shot sleeve is referred to as externally solidified product, or, when identified as a casting defect, as cold flakes. This project was directed to extending the understanding of the effects of externally solidified product on the cold chamber die casting process and products to enable the production of defect-free die castings and reduce the energy associated with these products. The projected energy savings from controlling the fraction of externally solidified product in die cast components is 40 x 10 Btu through the year 2025.

Carroll Mobley; Yogeshwar Sahai; Jerry Brevick

2003-10-10

77

Research on Alloying Tecniques of Mischmetal in Die Casting Magnesium Alloy  

Microsoft Academic Search

An aim of the experiments is to study alloying techniques of dollop-like MM, as-cast and extruded Mg-MM master alloy in die casting AZ91D magnesium alloy at conventional cold chamber die casting temperature. The as-cast AZ91D-1.2wt%MM alloys were prepared and MM was added by different way at 720C. The results showed that the efficiency of alloying achieved less than 50% within

Yulei Xu; Kui Zhang; Xinggang Li; Kang Zhang; Jian Lei; Haibo Yuan

2009-01-01

78

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

79

Die casting die deflections: Prediction and attenuation. 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 or 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.Allen; Ahuett-Garza, Horacio; Choudhury, Aswin K.; Dedhia, Sanjay

1998-05-01

80

WARM WATER SCALE MODEL EXPERIMENTS FOR MAGNESIUM DIE CASTING  

SciTech Connect

High-pressure die casting (HPDC) involves the filling of a cavity with the molten metal through a thin gate. High gate velocities yield jet break-up and atomization phenomena. In order to improve the quality of magnesium parts, the mold filling pattern, including atomization phenomena, needs to be understood. The goal of this study was to obtain experimental data on jet break-up characteristics for conditions similar to that of magnesium HPDC, and measure the droplet velocity and size distribution. A scale analysis is first presented in order to identify appropriate analogue for liquid magnesium alloys. Based on the scale analysis warm water was chosen as a suitable analogue and different nozzles were manufactured. A 2-D component phase Doppler particle analyzer (PDPA) and 2-D component particle image velocimetry (PIV) were then used to obtain fine particle diameter and velocity distributions in 2-D plane.

Sabau, Adrian S [ORNL

2006-01-01

81

Modelling the pressure die casting process using boundary and finite element methods  

Microsoft Academic Search

This paper is concerned with an investigation into the benefits and problems of modelling the pressure die casting process using a finite element solidification model for the casting and boundary element model for the die. Linking boundary and finite element methods is beset with difficulties with each method requiring different mesh, time-step and other requirements for accurate results. The numerical

K. Davey; S. Bounds

1997-01-01

82

Casting defects and fatigue strength of a die cast aluminium alloy: a comparison between standard specimens and production components  

Microsoft Academic Search

The influence of casting defects on static and fatigue strength is investigated for a high pressure die cast aluminium alloy. Defects exist in gas and shrinkage pores as well as cold fills, dross and alumina skins. For the three batches of specimens, differing for the spruerunner design, the influence was straightforward, while no significant variation in the fatigue strength was

M. Avalle; G. Belingardi; M. P. Cavatorta; R. Doglione

2002-01-01

83

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

84

Deep Drilling of Aluminium Die-Cast Parts: Surface Roughness, Dimensional Tolerance, and ToolChip Interaction  

Microsoft Academic Search

Many automotive applications require deep drilling on pressure die-cast parts in Aluminium alloys. The aim of the research was to understand if common cutting practices, usually determined on raw materials, can be successful on semimanufactured parts as well, having an inhomogeneous microstructure. A specific investigation was carried out on deep drilling of an EN AB-46000 cylinder block, varying technological parameters

Elena Bassoli; Luca Iuliano; Alessandro Salmi

2010-01-01

85

Understanding the Relationship Between Filling Pattern and Part Quality in Die Casting  

SciTech Connect

The overall objective of this research project was to investigate phenomena involved in the filling of die cavities with molten alloy in the cold chamber die-casting process. It has long been recognized that the filling pattern of molten metal entering a die cavity influences the quality of die-cast parts. Filling pattern may be described as the progression of molten metal filling the die cavity geometry as a function of time. The location, size and geometric configuration of points of metal entry (gates), as well as the geometry of the casting cavity itself, have great influence on filling patterns. Knowledge of the anticipated filling patterns in die-castings is important for designers. Locating gates to avoid undesirable flow patterns that may entrap air in the casting is critical to casting quality - as locating vents to allow air to escape from the cavity (last places to fill). Casting quality attributes that are commonly flow related are non-fills, poor surface finish, internal porosity due to trapped air, cold shuts, cold laps, flow lines, casting skin delamination (flaking), and blistering during thermal treatment.

Jerald Brevick; R. Allen Miller

2004-03-15

86

Determining thermal fatigue of steels for die casting of aluminum alloys  

Microsoft Academic Search

1.The total deformation of a sample under the influence of thermal cycling and uniaxial stress characterizes the resistance to thermal fatigue of die-casting molds.2.Experimental determination of the deformation makes it possible to calculate the number of cycles to failure of die-casting molds due to thermal fatigue.3.Calculating the thermal fatigue by the method proposed makes it possible to compare different steels.

V. G. Gorbach; V. G. Alekhin; G. L. Kurganova

1977-01-01

87

The influence of pressure during solidification of high pressure die cast aluminium telecommunications components  

Microsoft Academic Search

The effects of process variables on the quality of high-pressure die cast components was determined with the aid of in-cavity pressure sensors. In particular, the effects of set intensification pressure, delay time, and casting velocity have been investigated. The in-cavity pressure sensor has been used to determine how conditions within the die-cavity are related to the process parameters regulated by

Matthew S. Dargusch; G. Dour; N. Schauer; C. M. Dinnis; G. Savage

2006-01-01

88

Relationship between internal porosity and fracture strength of die-cast magnesium AM60B alloy  

Microsoft Academic Search

A die-cast magnesium alloy was examined with the use of X-ray tomography. Five tensile samples cut from different locations of a thin-walled, high-pressure magnesium die-casting were analyzed. The size and locations of pores in each sample were obtained from the X-ray tomography data. A critical local strain model was used to predict the fracture properties of the tensile samples. The

J. P. Weiler; J. T. Wood; R. J. Klassen; E. Maire; R. Berkmortel; G. Wang

2005-01-01

89

Die thermal behavior in machine casting of partially solid high temperature alloys  

Microsoft Academic Search

Experimental measurements and computer simulations of die thermal behavior during machine (die) casting of fully liquid and\\u000a partially solid bronze alloy 905 were carried out. Ingots of the alloy were heated to temperatures above the liquidus and\\u000a in the liquidsolid range in a reheat furnace. The partially solidified charge was previously made in a continuous slurry producer.\\u000a Castings were made

D. G. Backman; R. Mehrabian; M. C. Flemings

1977-01-01

90

Creep behavior of the die-cast MgAl alloy AS21  

Microsoft Academic Search

Creep behavior of the die-cast MgAl-based alloy AS21 was investigated at temperatures up to 150C in compression. The obtained stress exponent n is in the range of 1319. Microstructure observation clarified that the die-cast magnesium alloy is hardened by the stable rod-shaped Mg2Si precipitates. The induction of a threshold stress into the analysis leads to a stress exponent of 5,

P. Zhang

2005-01-01

91

Influence of porosity on the fatigue limit of die cast magnesium and aluminium alloys  

Microsoft Academic Search

High cycle fatigue properties of high-pressure die-cast magnesium alloys AZ91 hp, AM60 hp, AE42 hp, AS21 hp and of similarly produced cast aluminium alloy AlSi9Cu3 have been investigated. Ultrasonic fatigue tests up to 109 cycles show mean fatigue limits of approx. 3850 MPa (magnesium alloys) and 75 MPa (AlSi9Cu3) in the tested casting condition. Fatigue cracks initiated at porosity in

H Mayer; M Papakyriacou; B Zettl; S. E Stanzl-Tschegg

2003-01-01

92

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

93

On-line ultrasonic monitoring of a die-casting process using buffer rods  

Microsoft Academic Search

On-line ultrasonic monitoring of die casting of an aluminum plate with steps of different thicknesses is studied using pulse-echo techniques. Clad buffer rods are inserted into the die wall for the monitoring. The flow front of molten aluminum inside the die has been probed by a two-channel acquisition system with a time resolution up to 1 ms. This information may

C.-K. Jen; B. Cao; K. T. Nguyen; C. A. Loong; J.-G. Legoux

1997-01-01

94

Relation between cooling rates and microstructures in gravity-die-cast AZ91D disks  

SciTech Connect

In-die temperature measurements during the casting of 3.5- and 11.7-mm-thick disks in metal dies at 100 C, 200 C, and 400 C enables calculating of the heat flux from the casting to the die as a function of the casting parameters. Using the flux so determined, the temperature field in the plates could be calculated in agreement with measured values. Increasing preheating temperatures reduced the heat flux, which extended the local solidification time and coarsened the structure. Directional solidification, from the wall of the die to the center of the disk, took place only when casting a thin disk in a die at 400 C, because of the combination of low undercooling (which prevents homogeneous nucleation) and a sufficiently steep temperature gradient at the solidification front to ensure directional growth. A relatively long residence time at the high temperature, as occurs during casting in a die at 400 C, leads to a more-uniform distribution of the Al, due to diffusion in the solid, and prevents the divorced eutectic, distinct from that obtained at slow solidification, of the AZ91D ingot.

Avishei, A.; Bamberger, M. [Technion, Haifa (Israel). Dept. of Materials Engineering

1999-08-01

95

Nanocrystalline TiC powder alloying and glazing of H13 steel using a CO 2 laser for improved life of die-casting dies  

Microsoft Academic Search

Premature failures of die-casting dies used in the metal casting industry occur because of the damage caused by thermal fatigue, erosion, stress corrosion, and soldering on the die surfaces. In this work, the effects of two laser surface-treatment methods for the prevention of die failures were investigated. A 1500-W CO2 laser with round and line beam-shapes was employed to glaze

Wenping Jiang; Pal Molian

2001-01-01

96

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

97

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

98

Impact behaviour of A356 alloy for low-pressure die casting automotive wheels  

Microsoft Academic Search

Instrumented impact strength tests have been carried out on KV sub-size Charpy samples drawn from A356 aluminium alloy 17-in. wheels, produced by a low-pressure die casting. The wheels show different geometry and thermal treatment. In this paper, the effects of microstructure and defects on the impact properties are studied. The results indicate that the impact energy is lower in as-cast

Mattia Merlin; Giulio Timelli; Franco Bonollo; Gian Luca Garagnani

2009-01-01

99

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

100

High cycle fatigue of a die cast AZ91ET4 magnesium alloy  

Microsoft Academic Search

This study reveals the micro-mechanisms of fatigue crack nucleation and growth in a commercial high-pressure die cast automotive AZ91E-T4 Mg component. Mechanical fatigue tests were conducted under R=?1 conditions on specimens machined at different locations in the casting at total strain amplitudes ranging from 0.02% to 0.5%. Fracture surfaces of specimens that failed in the high cycle fatigue regime with

M. F Horstemeyer; N Yang; Ken Gall; D. L McDowell; J Fan; P. M Gullett

2004-01-01

101

Crossing Line Profile: A New Approach to Detecting Defects in Aluminium Die Castings  

Microsoft Academic Search

Radioscopy is the accepted way for controlling the quality of aluminium die cast pieces through computer-aided analysis of\\u000a X-ray images. Two classes of regions are possible in a digital X-ray image of a casting: regions belonging to regular structures\\u000a of the specimen, and those relating to defects. Since the contrast between a flaw and a defect-free neighbourhood is distinctive,\\u000a the

Domingo Mery

2003-01-01

102

Fatigue behaviour of friction stir processed AZ91 magnesium alloy produced by high pressure die casting  

Microsoft Academic Search

The room temperature fatigue properties of AZ91 magnesium alloy produced by high pressure die casting (HPDC) as cast, heat treated, friction stir processed (FSP) and FSP and heat treated were studied. The fatigue properties of the material were evaluated for the HPDC magnesium alloy in the as-received state and after a solution treatment at 415C for 2h and an ageing

P.. Cavaliere; P. P. De Marco

2007-01-01

103

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

104

Advances in aluminum casting technology  

SciTech Connect

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

Tiryakioglu, M.; Campbell, J. (eds.)

1998-01-01

105

Utility of micro-indentation technique for characterization of the constitutive behavior of skin and interior microstructures of die-cast magnesium alloys  

Microsoft Academic Search

There has been increasing thrust lately on the development of lightweight cast magnesium alloy components for structural automotive and other applications. The microstructure of the high-pressure die-cast Mg alloys usually contains a fine-grained skin having a microstructure significantly different from that of the bulk material. Characterization of the local constitutive behavior of the skin microstructure is of interest as it

Zhaohui Shan; Arun M Gokhale

2003-01-01

106

Studies on Flow Characteristics at High-Pressure Die-Casting  

NASA Astrophysics Data System (ADS)

The flow and filling characteristics during injection of liquid aluminum during high-pressure die-casting is studied threefoldly: a) analytically, b) experimentally and c) numerically. A planar jet of liquid aluminum is formed at the ingate due to its small width (?O(10-3) m), its high aspect ratio (? 100) and high inlet velocity (up to 60 m/s). On the one hand, wavy disintegration of such a jet can inevitably lead to cold runs in the final casting. On the other hand, a high degree of atomization may strongly increase the porosity of the casting part. Both processes can highly reduce the mechanical stability of the product. Analytical investigations of Ohnesorge (or equivalently Weber) and Reynolds numbers show that the process of drop formation at the liquid planar free jet is dominated by atomization assuming an orifice nozzle geometry at the ingate. From a simple experimental investigation of an equivalent free jet of water, however, it is deduced that the process of drop formation can be changed to wavy disintegration by the nozzle geometry. Numerically, high-pressure die-casting is attacked by a Volume of Fluid approach. Although the drop formation at the phase interphase can not be captured by the numerical model since the drops are an order of magnitude smaller than feasible grid spacings, the global spreading of the free jet in the casting mold is well pictured by this first numerical simulation. In addition, a new approach is presented to detect cold runs at the final casting. Finally, the studies presented lead to an increased understanding of high pressure die casting and can help to improve the quality of casting products.

Schneiderbauer, S.; Pirker, S.; Chimani, C.; Kretz, R.

2012-01-01

107

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

108

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

109

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

110

Simulation of distortion and residual stress in high pressure die casting - modelling and experiments  

NASA Astrophysics Data System (ADS)

Two individual high-pressure die-casting geometries were developed in order to study the influence of process parameters and different alloys on the distortion behaviour of castings. These geometries were a stress lattice and a V-shaped sample tending to form residual stress due to different wall thickness respectively by a deliberate massive gating system. In the experimental castings the influence of the most important process parameters such as die temperature and die opening time and the cooling regime was examined. The time evolution of process temperatures was measured using thermal imaging. The heat transfer coefficients were adapted to the observed temperature distributions. Castings were produced from the two alloys AlSi12 and AlSi10MnMg. The distortion of the castings was measured by means of a tactile measuring device. For the alloy AlSi10MnMg thermo-physical and thermo-mechanical data were obtained using differential scanning calorimetry, laser flash technique, dilatometry and tensile testing at elevated temperatures. These data were used for modelling the material behaviour of the AlSi10MnMg alloy in the numerical model while for the alloy AlSi12(Fe) literature data were used. Process and stress simulation were conducted using the commercial FEM software ANSYS Workbench. A survey on the results of the comparison between simulation and experiment is given for both alloys.

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

2012-07-01

111

Wear mechanism maps of uncoated HSS tools drilling die-cast aluminum alloy  

Microsoft Academic Search

A map describing the flank wear characteristics of uncoated high-speed steel (HSS) tools is constructed under the condition of drilling die-cast aluminum alloy. Several wear mechanisms are revealed which describe different wear modes observed by SEM in uncoated HSS tools, including adhesive wear, adhesive and abrasive wear, abrasive wear, severely plastic flow, and thermal wear. In the map, there exists

M. Z Zhang; Y. B Liu; H Zhou

2001-01-01

112

On the optimum plunger acceleration law in the slow shot phase of pressure die casting machines  

Microsoft Academic Search

The objective of this paper is to analyse a plunger acceleration law that is expected to minimize air entrapment in the slow shot phase of pressure die casting in horizontal cold chambers, and thus to reduce porosity in manufactured parts. The study is carried out using results from an analytical model of the flow of molten metal in the shot

F Faura; J Lpez; J Hernndez

2001-01-01

113

Corrosion resistance of aged die cast magnesium alloy AZ91D  

Microsoft Academic Search

The corrosion behaviour of die cast magnesium alloy AZ91D aged at 160C was investigated. The corrosion rate of the alloy decreases with ageing time in the initial stages and then increases again at ageing times greater than 45h. The dependence of the corrosion rate on ageing time can be related to the changes in microstructure and local composition during ageing.

Guangling Song; Amanda L Bowles; David H StJohn

2004-01-01

114

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

115

Superplastic behaviour of friction stir processed AZ91 magnesium alloy produced by high pressure die cast  

Microsoft Academic Search

The room temperature and hot tensile properties of AZ91 magnesium alloy produced by high pressure die cast after friction stir processing (FSP) were studied in the present paper. Such process is a modification of classical friction stir welding one in which the sheets are not joined but the stirring action of the tool, on the bulk material, is used to

P. Cavaliere; P. P. De Marco

2007-01-01

116

Microstructural characterization of a die-cast magnesium-rare earth alloy  

Microsoft Academic Search

Microstructural characterization of high-pressure die-cast alloy MEZ (Mg2.5RE0.35Zn0.3Mn) reveals equiaxed dendrites of ?-Mg with a partially divorced interdendritic eutectic. Detailed diffraction studies coupled with WDS analysis reveal the presence of a continuous Mg12RE intermetallic phase in the eutectic aggregate along with fine Mg particles.

I. P Moreno; T. K Nandy; J. W Jones; J. E Allison; T. M Pollock

2001-01-01

117

3D SPH flow predictions and validation for high pressure die casting of automotive components  

Microsoft Academic Search

The geometric complexity and high fluid speeds involved in high pressure die casting (HPDC) combine to give strongly three-dimensional fluid flow with significant free surface fragmentation and splashing. A Lagrangian simulation technique that is particularly well suited to modelling HPDC is smoothed particle hydrodynamics (SPH). Materials are approximated by particles that are free to move around rather than by fixed

P. W. Cleary; J. Ha; M. Prakash; T. Nguyen

2006-01-01

118

Use of Taguchi method to develop a robust design for the magnesium alloy die casting process  

Microsoft Academic Search

This study applies the Taguchi method to optimize the process parameters for the die casting of thin-walled magnesium alloy parts in computer, communications, and consumer electronics (3C) industries. The objectives of the Taguchi method for robust parameter design are to establish the optimal combination of design parameters and to reduce the variation in quality from a minimum number of experiments.

Der Ho Wu; Mao Sheng Chang

2004-01-01

119

Three defect types in friction stir welding of aluminum die casting alloy  

Microsoft Academic Search

For different tool plunge downforces, the optimum FSW conditions of aluminum die casting alloy were examined. The higher the tool plunge downforce is, the wider the range of the optimum FSW conditions is. The following three different types of defects are formed, depending on the FSW conditions. (1) A large mass of flash due to the excess heat input; (2)

Y. G. Kim; H. Fujii; T. Tsumura; T. Komazaki; K. Nakata

2006-01-01

120

Die-casting effect on surface characteristics of thin-walled AZ91D magnesium components  

NASA Astrophysics Data System (ADS)

Filling trace, filling time and temperature distribution during the die-casting process were simulated using commercial software (MAGMA). The surface microstructure and phase distribution in thin-walled AZ91D magnesium components cast on a hot-chamber die-casting machine were investigated by means of optical microscopy and scanning electron microscopy. The depth profile of alloying elements was examined using a glow discharge optical emission spectrometer. The outer skin microstructure consists of more ?-phase and less eutectic ?-phase than the interior region. The elemental content of C, Si, and Fe in the outer skin increased along the filling trace, and they decreased with increasing distance from the surface to the interior region, while the Al had an inverse trend. The corrosion resistance decreased along the filling trace.

Hu, Lifang; Chen, Shaoping; Miao, Yang; Meng, Qingsen

2012-11-01

121

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

122

In-line ultrasonic monitoring of semi-solid magnesium die casting process.  

PubMed

Ultrasonic velocity and attenuation measurements in AZ91D magnesium (Mg) alloy with dendritic, rosette and globular microstructures were performed at elevated temperatures using a non-contact laser-ultrasonic technique. It was found that the ultrasonic velocity in the globular microstructure and the ultrasonic attenuation in the dendritic microstructure are the highest among the three microstructures. An ultrasonic clad steel buffer rod sensor embedded in the die has been used to monitor the semi-solid die casting process in-line for the AZ91D Mg alloy. This probe monitored the completion of the die filling, the release of the pressure, the opening of the die, part detachment, solidification of the part, the averaged temperature of the die and the part. PMID:15110535

Jen, C-K; Moisan, J-F; Zheng, C-Q; Loong, C A; Kruger, S E; Shehata, M T; Essadiqi, E

2004-05-01

123

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

124

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

125

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

126

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

127

Microstructural stability and creep properties of die casting Mg-4Al-4RE magnesium alloy  

SciTech Connect

The AE44 (Mg-4Al-4RE) alloy was prepared by a hot-chamber die casting method. The microstructure, microstructural stability and creep properties at 175 deg. C were investigated. The microstructure was analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and the Rietveld method. The results show that die cast AE44 magnesium alloy consists of {alpha}-Mg, Al{sub 11}RE{sub 3}, Al{sub 2}RE and Al{sub 2.12}RE{sub 0.88} phases. The Al{sub 11}RE{sub 3} phase is thermally stable at 175 deg. C whereas the metastable Al{sub 2.12}RE{sub 0.88} phase undergoes a transition into the equilibrium Al{sub 2}RE phase. The alloy investigated is characterized by good creep properties at temperatures of 175 deg. C and 200 {sup o}C.

Rzychon, Tomasz, E-mail: tomasz.rzychon@polsl.pl [Silesian University of Technology, Faculty of Materials Science and Metallurgy, Krasinskiego 8, 40-019 Katowice (Poland); Kielbus, Andrzej; Cwajna, Jan [Silesian University of Technology, Faculty of Materials Science and Metallurgy, Krasinskiego 8, 40-019 Katowice (Poland); Mizera, Jaroslaw [Warsaw University of Technology, Woloska 141, 02-507 Warsaw (Poland)

2009-10-15

128

Formation Mechanism of Discoloration on Die-Cast AZ91D Components Surface After Chemical Conversion  

NASA Astrophysics Data System (ADS)

A notebook (NB) computer component was manufactured from AZ91D Mg alloy by a die-casting process. After chemical conversion treatment, a discoloration was noted on the component surface. The source of this discoloration has been studied in detail by scanning electron microscopy, energy dispersive spectroscopy, and spark atomic absorption spectroscopy. The corrosion resistance was also measured by potentiodynamic polarization, hydrogen evolution and salt spray testing. The formation mechanism for the discoloration which was caused by the residue left behind by excess mold release agent sprayed during the die-casting was discussed in detail. After chemical conversion treatment, the residual-baked mold release agent was apparent on the component surface as "white ash." Consequently, it degraded seriously both the appearance and the corrosion resistance of the manufactured component.

Liu, Bao-sheng; Wei, Ying-hui; Hou, Li-feng

2013-01-01

129

Galvanic corrosion properties of differently PVD-treated magnesium die cast alloy AZ91  

Microsoft Academic Search

Different types of PVD coatings and plasma treatments were applied for the surface treatment of magnesium die cast alloy AZ91 specimens. The different types of surface treatment were all developed by the authors and the fundamental properties are described elsewhere. The coating systems were:9 ?m CrN hard coating3 ?m TiN coating0.5 ?m plasma anodisation layer and 3 ?m Al2O3 coatingThe

H. Hoche; C. Blawert; E. Broszeit; C. Berger

2005-01-01

130

Improvement of mechanical properties of aluminum die casting alloy by multi-pass friction stir processing  

Microsoft Academic Search

An improvement in the mechanical properties was accomplished due to the microstructural modification of an aluminum die casting alloy by multi-pass friction stir processing (MP-FSP), which is a solid-state microstructural modification technique using a frictional heat and stirring action. The hardness of the MP-FSP sample is about 20Hv higher than that of the base metal. The tensile strengths of the

K. Nakata; Y. G. Kim; H. Fujii; T. Tsumura; T. Komazaki

2006-01-01

131

Fatigue crack growth behaviour of a die-cast magnesium alloy AZ91D  

Microsoft Academic Search

This paper deals with the room temperature fatigue crack growth behaviour of a die-cast magnesium alloy AZ91D. Short and long fatigue crack growth studies were done using single edge V-notched plate specimens under pulsating tension with a stress ratio of 0.1 and a frequency of 20 Hz at different maximum applied stress levels. Retardationacceleration in growth of short cracks was

P Venkateswaran; S Ganesh Sundara Raman; S. D Pathak; Y Miyashita; Y Mutoh

2004-01-01

132

A thousandfold creep strengthening by Ca addition in die-cast AM50 magnesium alloy  

Microsoft Academic Search

The effect of calcium addition on the microstructure and creep strength of the die-cast AM50 magnesium alloy was investigated.\\u000a The ?-Mg grains with the diameter of 4.9 m are surrounded by the eutectic phases for the AM50-1.72 mass pct Ca alloy, while the ?(Mg17Al12) particles are located mainly on the grain boundaries of the ? grains for the AM50 alloy.

Yoshihiro Terada; Rie Sota; Naoya Ishimatsu; Tatsuo Sato; Koichi Ohori

2004-01-01

133

Development of creep resistant die cast MgSnAlSi alloy  

Microsoft Academic Search

A study has been made on the tensile properties and high temperature properties of die cast MgSnAlSi (TAS831) alloy. The microstructure of TAS831 alloy is characterized by the presence of thermally stable Mg2Sn particles within matrix and along grain boundaries. It also contains a small volume fraction of thermally stable Mg2Si particles. It has been shown that TAS831 alloy has

Dae H. Kang; Sung S. Park; Nack J. Kim

2005-01-01

134

Microstructure of a pressure die cast magnesium4wt.% aluminium alloy modified with rare earth additions  

Microsoft Academic Search

Addition of cerium-rich mixtures of rare earth (RE) elements to aluminium-containing magnesium pressure die cast alloys is known to improve the creep properties at elevated temperatures. In the present investigation, a detailed description of the microstructure of a magnesium-4 wt.% aluminium alloy containing 1.4 wt.% of a cerium-rich mixture of RE elements is presented. Particle types occurring and their distribution

G. Pettersen; H. Westengen; R. Hier; O. Lohne

1996-01-01

135

Multilayered chromium\\/chromium nitride coatings for use in pressure die-casting  

Microsoft Academic Search

Chromium nitride coatings are known to give reasonable solutions to the requirements of semisolid forming tools and of pressure die-casting of low-melting-point metals and alloys. These hard coatings have good mechanical behavior when working at high temperatures. They show enhanced hardness and good wear and corrosion resistance, as well as reduced adhesion to the molten or semisolid metal. We have

A Lousa; J Romero; E Mart??nez; J Esteve; F Montal; L Carreras

2001-01-01

136

Microstructure and creep behavior in AE42 magnesium die-casting alloy  

Microsoft Academic Search

The micro structural analysis of die-cast AE42 reveals a correlation between micro structure and creep strength. A lamellar-phase\\u000a Al11RE3, which dominates the interdendritic microstructure of the alloy, partly decomposes above 150C into Al2RE and Al (forming Mg17Al12). The increased solubility of aluminum in magnesium at higher temperatures may also promote the decomposition of Al11RE3. The creep strength decreases sharply with

Bob R. Powell; Vadim Rezhets; Michael P. Balogh; Richard A. Waldo

2002-01-01

137

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

138

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.

139

2005 May JOM 35 Casting DefectsOverview  

E-print Network

, for commercial applications, die casting is used as a net-shape process. Die cast- ing, a common technique, on the other hand, are slow cool- ing and small temperature gradients. In a die-cast process, the liquid BMG2005 May · JOM 35 Casting DefectsOverview Superplastic forming (SPF) is intro- duced

Haller, Gary L.

140

Machining studies of die cast aluminum alloy-silicon carbide composites  

NASA Astrophysics Data System (ADS)

Metal matrix composites (MMCs) with high specific stiffness, high strength, improved wear resistance, and thermal properties are being increasingly used in advanced structural, aerospace, automotive, electronics, and wear applications. Aluminum alloy-silicon carbide composites were developed using a new combination of the vortex method and the pressure die-casting technique in the present work. Machining studies were conducted on the aluminum alloy-silicon carbide (SiC) composite work pieces using high speed steel (HSS) end-mill tools in a milling machine at different speeds and feeds. The quantitative studies on the machined work piece show that the surface finish is better for higher speeds and lower feeds. The surface roughness of the plain aluminum alloy is better than that of the aluminum alloy-silicon carbide composites. The studies on tool wear show that flank wear increases with speed and feed. The end-mill tool wear is higher on machining the aluminum alloy-silicon carbide composites than on machining the plain aluminum alloy.

Sornakumar, Thambu; Kathiresan, Marimuthu

2010-10-01

141

Energy Saving Melting and Revert Reduction Technology: Improved Die Casting Process to Preserve the Life of the Inserts  

SciTech Connect

The goal of this project was to study the combined effects of die design, proper internal cooling and efficient die lubricants on die life. The project targeted improvements in die casting insert life by: Optomized Die Design for Reduced Surface Temperature: The life of die casting dies is significantly shorter when the die is exposed to elevated temperature for significant periods of time. Any die operated under conditions leading to surface temperature in excess of 1050oF undergoes structural changes that reduce its strength. Optimized die design can improve die life significantly. This improvement can be accomplished by means of cooling lines, baffles and bubblers in the die. A key objective of the project was to establish criteria for the minimal distance of the cooling lines from the surface. This effort was supported with alloys and machining by BohlerUddeholm, Dunn Steel, HH Stark and Rex Buckeye. In plant testing and evaluation was conducted as in-kind cost share at St. Clair Die Casting. The Uddeholm Dievar steel evaluated in this program showed superior resistance to thermal fatigue resistance. Based on the experimental evidence, cooling lines could be placed as close as 0.5" from the surface. Die Life Extension by Optimized Die Lubrication: The life of die casting dies is affected by additions made to its surface with the proper lubricants. These lubricants will protect the surface from the considerable temperature peaks that occur when the molten melt enters the die. Dies will reach a significantly higher temperature without this lubricant being applied. The amount and type of the lubricant are critical variables in the die casting process. However, these lubricants must not corrode the die surface. This effort was supported with alloys and machining by BohlerUddeholm, Dunn Steel, HH Stark and Rex Buckeye. In plant testing and evaluation was conducted as in-kind cost share at St. Clair Die Casting. Chem- Trend participated in the program with die lubricants and technical support. Experiments conducted with these lubricants demonstrated good protection of the substrate steel. Graphite and boron nitride used as benchmarks are capable of completely eliminating soldering and washout. However, because of cost and environmental considerations these materials are not widely used in industry. The best water-based die lubricants evaluated in this program were capable of providing similar protection from soldering and washout. In addition to improved part quality and higher production rates, improving die casting processes to preserve the life of the inserts will result in energy savings and a reduction in environmental wastes. Improving die life by means of optimized cooling line placement, baffles and bubblers in the die will allow for reduced die temperatures during processing, saving energy associated with production. The utilization of optimized die lubricants will also reduce heat requirements in addition to reducing waste associated with soldering and washout. This new technology was predicted to result in an average energy savings of 1.1 trillion BTU's/year over a 10 year period. Current (2012) annual energy saving estimates, based on commercial introduction in 2010, a market penetration of 70% by 2020 is 1.26 trillion BTU's/year. Along with these energy savings, reduction of scrap and improvement in casting yield will result in a reduction of the environmental emissions associated with the melting and pouring of the metal which will be saved as a result of this technology. The average annual estimate of CO2 reduction per year through 2020 is 0.025 Million Metric Tons of Carbon Equivalent (MM TCE).

David Schwam, PI; Xuejun Zhu, Sr. Research Associate

2012-09-30

142

On the influence of process variables on the thermal conditions and properties of high pressure die-cast magnesium alloys  

Microsoft Academic Search

The influence of pressure and velocity in high-pressure magnesium die casting on the thermal conditions and on the casting properties is studied. Specimens with the shape of a tensile test plate with a thickness of 12 mm and a length of 295 mm were cast using the alloys AM20HP, AM50HP, AS41, AE42, AZ91HP. Two gate velocities of the liquid metal

Nahed A. El-Mahallawy; Mohamed A Taha; Engenius Pokora; Friedrich Klein

1998-01-01

143

Effect of substituting cerium-rich mischmetal with lanthanum on high temperature properties of die-cast MgZnAlCaRE alloys  

Microsoft Academic Search

MgZnAlCaRE alloys have been found to be promising materials for substituting aluminum alloys used for automatic transmission case applications in the automobile industry. Particularly, Mg0.5%Zn6%Al1%Ca3%RE (ZAXE05613) alloy exhibits comparable creep resistance as ADC12 die-casting aluminum alloy that is currently used for automatic transmission case applications. Changing the rare earth (RE) content of the alloy from mischmetal to lanthanum gives a

Ifeanyi A Anyanwu; Yasuhiro Gokan; Atsuya Suzuki; Shigeharu Kamado; Yo Kojima; Suguru Takeda; Taketoshi Ishida

2004-01-01

144

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

145

Sand, die and investment cast parts via the SLS selective laser sintering process  

NASA Astrophysics Data System (ADS)

Complex three-dimensional parts can be manufactured directly from CAD data using rapid prototyping processes. SLS selective laser sintering is a rapid prototyping process developed at the University of Texas at Austin and commercialized by DTM Corporation. SLS parts are constructed layer by layer from powdered materials using laser energy to melt CAD specified cross sections. Polymer, metal, and ceramic powders are all potential candidate materials for this process. In this paper the fabrication of complex metal parts rapidly using the investment, die and sand casting technologies in conjunction with the selective laser sintering process are being explained and discussed. TrueForm and polycarbonate were used for investment casting, while RapidSteel metal mould inserts were used for the die casting trials. Two different SandForm materials, zircon and silica sand, are currently available for the direct production of sand moulds and cores. The flexible and versatile selective laser sintering process all these materials on one single sinterstation. Material can be changed fast and easily between two different builds.

van de Crommert, Simon; Seitz, Sandra; Esser, Klaus K.; McAlea, Kevin

1997-09-01

146

Fatigue Life Prediction in Rapid Die Casting - Preliminary Work in View of Current Research  

SciTech Connect

Numerical simulation technique as a prediction tool is slowly adopted in metal casting industry for predicting design modelling solidification analysis. The reasons for this activity is found in the need to further enhance the geometrical design and mechanical properties of the tool design and the correct prediction methodology to fulfil industrial needs. The present state of numerical simulation capabilities in rapid die casting technologies is reviewed and the failure mode mechanisms of thermal fatigue, aimed at developing a numerical simulation with a systematic design guidance for predicting the thermal cyclic loading analysis and improvement is presented along with several other methods. The economic benefits of a numerical simulation technique in die casting are limited to tool life time, mechanical properties and design guidance. The extensive computer capabilities of a numerical simulation with a systematic design guidance methodology are exploited to provide a solution for flexible design, mechanical properties and mould life time. Related research carried out worldwide by different organisations and academic institutions are discussed.

Chuan Huat Ng [Faculty of Mechanical and Manufacturing Engineering (FKMP), Kolej Universiti Teknologi Tun Hussein Onn (KUiTTHO), P.O.Box 101, 86400 Parit Raja, Batu Pahat, Johor (Malaysia); Grote, Karl-Heinrich [Institut fuer Maschinenkonstruktion, Lehrstuhl Konstruktionstechnik, Otto-von-Guericke University Magdeburg, Universitaetsplatz 2, 39106 Magdeburg (Germany); Baehr, Ruediger [Institut fuer Fertigungstechnik und Qualitaetssicherung, Ur und Umformtechnik, Otto-von-Guericke University Magdeburg, Universitaetsplatz 2, 39106 Magdeburg (Germany)

2007-05-17

147

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

148

Semi solid metal (SSM) casting: Applications and case stories in aluminum and magnesium  

SciTech Connect

A semi-solid metal (SSM) casting process based around real time controlled horizontal cold chamber die casting machines is described. SSM casting has been successfully applied to both aluminum and magnesium alloys with the largest shot weight to date being 11.5 kilogram (25 pounds). SSM casting offers a unique combination of near net shape and premium quality mechanical performance. Aluminum components generally require either partial (T5) or full (T6) heat treatment providing attractive combinations of strength and ductility. In the case of magnesium alloys, the ability to completely eliminate liquid metal handling from the casting floor allows SSM casting to compete with magnesium cold chamber die casting. In these instances, less massive gating than for aluminum is required and normal trimming operations can be considered. A series of case studies are presented together with projections for future developments. As raw material costs decrease and secondary recycling becomes viable it is expected that SSM casting will be considered for a much wider range of applications.

Young, K.P. [Buhler Inc., Uzwil (Switzerland)

1996-10-01

149

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.; Cceres, C. H.; Nagasekhar, A. V.; Easton, M. A.

2012-03-01

150

Fatigue behaviour of friction stir processed AZ91 magnesium alloy produced by high pressure die casting  

SciTech Connect

The room temperature fatigue properties of AZ91 magnesium alloy produced by high pressure die casting (HPDC) as cast, heat treated, friction stir processed (FSP) and FSP and heat treated were studied. The fatigue properties of the material were evaluated for the HPDC magnesium alloy in the as-received state and after a solution treatment at 415 deg. C for 2 h and an ageing treatment at 220 deg. C for 4 h. The heat treatment resulted in a significant increase in the fatigue properties of the HPDC material, while no significance influence of heat treatment was recorded in the FSP condition. The morphology of fracture surfaces was examined by employing a field emission gun scanning electron microscope (FEGSEM)

Cavaliere, P. [INFM-Dept. of 'Ingegneria dell'Innovazione', Engineering Faculty, University of Lecce, Via per Arnesano, 73100, Lecce (Italy)]. E-mail: pasquale.cavaliere@unile.it; De Marco, P.P. [INFM-Dept. of 'Ingegneria dell'Innovazione', Engineering Faculty, University of Lecce, Via per Arnesano, 73100, Lecce (Italy)

2007-03-15

151

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

152

Microstructure of high pressure die cast AZ91D modified with Ca and Ce  

Microsoft Academic Search

High pressure die cast (HPDC) AZ91D (Mg8.8wt%Al0.74wt%Zn0.29wt%Mn) modified with Ca and Ce was investigated. Thermodynamic calculations of liquid\\/solid equilibrium were confirmed by DTA measurements and solid\\/liquid equilibrium at various temperatures between the liquidus and solidus temperatures.The solidification path of HPDC AZ91 and AZ91 modified with Ca and Ce was calculated using the Termo-Calc program. The microstructure was investigated utilizing optical

L. Shepeleva; M. Bamberger

2006-01-01

153

Strategies to reduce the environmental impact of an aluminium pressure die casting plant: a scenario analysis.  

PubMed

This study explores a model (MIKADO) to analyse scenarios for the reduction of the environmental impact of an aluminium die casting plant. Our model calculates the potential to reduce emissions, and the costs associated with implementation of reduction options. In an earlier paper [Neto, B., Kroeze, C., Hordijk, L., Costa, C., 2008. Modelling the environmental impact of an aluminium pressure die casting company and options for control. Environmental Modelling & Software 23 (2) 147-168] we included the model description and explored the model by applying it to a plant in which no reduction options are assumed to be implemented (so-called zero case, reflecting the current practice in the plant). Here, we perform a systematic analysis of reduction options. We analysed seven types of reduction strategies, assuming the simultaneous implementation of different reduction options. These strategies are analysed with respect to their potential to reduce emissions, environmental impact and costs associated with the implementation of options. These strategies were found to differ largely in their potential to reduce the environmental impact of the plant (10-87%), as well as in the costs associated with the implementation of options (-268 to +277keuro/year). We were able to define 11 strategies, reducing the overall environmental impact by more than 50%. Of these, two have net negative costs, indicating that the company may in fact earn money through their implementation. PMID:18342428

Neto, Belmira; Kroeze, Carolien; Hordijk, Leen; Costa, Carlos; Pulles, Tinus

2009-02-01

154

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

155

Casting Process Simulation Based of Interface Friction between Metallic Liquid and Die Wall  

NASA Astrophysics Data System (ADS)

Rapid Tooling (RT) is a major field in rapid prototyping manufacturing (RPM). In order to obtain metallic molds for automobile industry, ceramic shell precision casting technology is being used. Models are used in this kind of casting technology in RT in our lab. Some main factors have been analysed and estimated. MARC nonlinear finite element analysis software has been used for calculation of size change in the casting process. Selection of boundary conditions in the solidification process is the most important. There is interface friction between metallic liquid and die wall. Except influence in size change due to phase transition and cooling process, this friction force in tangential direction could give severe influence on the size change. If this factor is not considered in the calculation for size change, there is a large difference between real value and calculated value. We use this new model instead of usual contact model, a better result has been obtained. Work supported by the National Natural Science Foundation of China.

Zhang, Renji; Liu, Yuan; Xu, Da; Yan, Yongnian

1998-03-01

156

An evaluation of fiberglass cast application techniques.  

PubMed

Cylindrical casts constructed from 2, 3, 4, and 5 inch widths of fiberglass casting material were evaluated for strength in bending using an unstable fracture model. Five-inch casting material produced the strongest casts. The effect of longitudinal splinting with 2-inch fiberglass tape was evaluated in cylindrical casts constructed from 4-inch tape. Casts with splints on the compression side or with splints on both the tension and compression sides were stronger in bending than casts with a single splint on the tension side or casts without splints. PMID:7778250

Wilson, D G; Vanderby, R

1995-01-01

157

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

158

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

159

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 Engineering , ABC-NACO TECHNOLOGIES, Lombard, IL1 Project Engineer - Casting Simulation, ABC-NACO TECHNOLOGIES castings, and comparisons are made between these new rules and the feeding rules presently published

Beckermann, Christoph

160

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

161

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

Code of Federal Regulations, 2010 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...

2010-07-01

162

Development of a 3-D thermal model of the low-pressure die-cast (LPDC) process of A356 aluminum alloy wheels  

Microsoft Academic Search

A mathematical model of the low-pressure die casting process for the production of A356 aluminum alloy wheels has been developed to predict the evolution of temperature within the wheel and die under the auspices of a collaborative research agreement between researchers at the University of British Columbia and a North American wheel casting facility. The heat transfer model represents a

B. Zhang; D. M. Maijer; S. L. Cockcroft

2007-01-01

163

Quantitative characterization of processing-microstructure-properties relationships in pressure die-cast magnesium alloys  

NASA Astrophysics Data System (ADS)

The central goal of this research is to quantitatively characterize the relationships between processing, microstructure, and mechanical properties of important high-pressure die-cast (HPDC) Mg-alloys. For this purpose, a new digital image processing technique for automatic detection and segmentation of gas and shrinkage pores in the cast microstructure is developed and it is applied to quantitatively characterize the effects of HPDC process parameters on the size distribution and spatial arrangement of porosity. To get better insights into detailed geometry and distribution of porosity and other microstructural features, an efficient and unbiased montage based serial sectioning technique is applied for reconstruction of three-dimensional microstructures. The quantitative microstructural data have been correlated to the HPDC process parameters and the mechanical properties. The analysis has led to hypothesis of formation of new type of shrinkage porosity called, "gas induced shrinkage porosity" that has been substantiated via simple heat transfer simulations. The presence of inverse surface macrosegregation has been also shown for the first time in the HPDC Mg-alloys. An image analysis based technique has been proposed for simulations of realistic virtual microstructures that have realistic complex pore morphologies. These virtual microstructures can be implemented in the object oriented finite elements framework to model the variability in the fracture sensitive mechanical properties of the HPDC alloys.

Lee, Soon Gi

164

Variability in the tensile ductility of high-pressure die-cast AM50 Mg-alloy  

Microsoft Academic Search

Variability in the tensile ductility of high-pressure die-cast AM50 Mg-alloy is examined at five different test temperatures. The fracture path preferentially goes through the regions of clusters of pores. The percent ductility is correlated to area fraction of porosity in the fracture surfaces using a power law equation.

S. G. Lee; G. R. Patel; A. M. Gokhale; A. Sreeranganathan; M. F. Horstemeyer

2005-01-01

165

Simulation-based selection of optimum pressure die-casting process parameters using neural nets and genetic algorithms  

Microsoft Academic Search

Pressure die-casting condition selection mainly relies on the experience and expertise of individuals working in production industries. Systematic knowledge accumulation regarding the manufacturing process is essential in order to obtain optimal process conditions. It is not safe a priori to presume that rules of thumb, which are widely used on the shop floor, always lead to fast prototype production calibration

A. Krimpenis; P. G. Benardos; G.-C. Vosniakos; A. Koukouvitaki

2006-01-01

166

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

167

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; Rbner, Matthias; Ilg, Jrgen; Rupitsch, Stefan J.; Lerch, Reinhard; Singer, Robert F.; Krner, Carolin

2012-11-01

168

Low-Cycle Fatigue Behavior of Die-Cast Mg Alloys AZ91 and AM60  

NASA Astrophysics Data System (ADS)

The influence of microstructure and artificial aging response (T6) on the low-cycle fatigue behavior of super vacuum die-cast (SVDC) AZ91 and AM60 has been investigated. Fatigue lifetimes were determined from the total strain-controlled fatigue tests for strain amplitudes of 0.2 pct, 0.4 pct, 0.6 pct, 0.8 pct, and 1.0 pct under fully reversed loading at a frequency of 5 Hz. Cyclic stress-strain behavior was determined using an incremental step test (IST) and compared with the more traditional constant amplitude test. Two locations in a prototype casting were investigated to examine the role of microstructure and porosity on fatigue behavior. At all total strain amplitudes microstructure refinement had a negligible impact on fatigue life because of significant levels of porosity. AM60 showed an improvement in fatigue life at higher strain amplitudes when compared with AZ91 because of higher ductility. T6 heat treatment had no impact on fatigue life. Cyclic stress-strain behavior obtained via the incremental step test varied from constant amplitude test results due to load history effects. The constant amplitude test is believed to be the more accurate test method. In general, larger initiation pores led to shorter fatigue life. The fatigue life of AZ91 was more sensitive to initiation pore size and pore location than AM60 at the lowest tested strain amplitude of 0.2 pct. Fatigue crack paths did not favor any specific phase, interdentritic structure or eutectic structure. A multistage fatigue (MSF) model showed good correlation to the experimental strain-life results. The MSF model reinforced the dominant role of inclusion (pore) size on the scatter in fatigue life.

Rettberg, Luke H.; Jordon, J. Brian; Horstemeyer, Mark F.; Jones, J. Wayne

2012-07-01

169

21 CFR 888.5980 - Manual cast application and removal instrument.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Manual cast application and removal instrument...Surgical Devices 888.5980 Manual cast application and removal instrument. (a) Identification. A manual cast application and removal...

2010-04-01

170

21 CFR 888.5980 - Manual cast application and removal instrument.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Manual cast application and removal instrument...Surgical Devices 888.5980 Manual cast application and removal instrument. (a) Identification. A manual cast application and removal...

2013-04-01

171

21 CFR 888.5980 - Manual cast application and removal instrument.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Manual cast application and removal instrument...Surgical Devices 888.5980 Manual cast application and removal instrument. (a) Identification. A manual cast application and removal...

2012-04-01

172

21 CFR 888.5980 - Manual cast application and removal instrument.  

...2014-04-01 2014-04-01 false Manual cast application and removal instrument...Surgical Devices 888.5980 Manual cast application and removal instrument. (a) Identification. A manual cast application and removal...

2014-04-01

173

21 CFR 888.5980 - Manual cast application and removal instrument.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Manual cast application and removal instrument...Surgical Devices 888.5980 Manual cast application and removal instrument. (a) Identification. A manual cast application and removal...

2011-04-01

174

Microstructural Evolution and Solidification Behavior of Al-Mg-Si Alloy in High-Pressure Die Casting  

NASA Astrophysics Data System (ADS)

Microstructural evolution and solidification behavior of Al-5 wt pct Mg-1.5 wt pct Si-0.6 wt pct Mn-0.2 wt pct Ti alloy have been investigated using high-pressure die casting. Solidification commences with the formation of primary ?-Al phase in the shot sleeve and is completed in the die cavity. The average size of dendrites and fragmented dendrites of the primary ?-Al phase formed in the shot sleeve is 43 ?m, and the globular primary ?-Al grains formed inside the die cavity is at a size of 7.5 ?m. Solidification inside the die cavity also forms the lamellar Al-Mg2Si eutectic phase and the Fe-rich intermetallics. The size of the eutectic cells is about 10 ?m, in which the lamellar ?-Al phase is 0.41 ?m thick. The Fe-rich intermetallic compound exhibits a compact morphology and is less than 2 ?m with a composition of 1.62 at. pct Si, 3.94 at. pct Fe, and 2.31 at. pct Mn. A solute-enriched circular band is always observed parallel to the surface of the casting. The band zone separates the outer skin region from the central region of the casting. The solute concentration is consistent in the skin region and shows a general drop toward the center inside the band for Mg and Si. The peak of the solute enrichment in the band zone is much higher than the nominal composition of the alloy. The die casting exhibits a combination of brittle and ductile fracture. There is no significant difference on the fracture morphology in the three regions. The band zone is not significantly detrimental in terms of the fracture mechanism in the die casting. Calculations using the Mullins and Sekerka stability criterion reveal that the solidification of the primary ?-Al phase inside the die cavity has been completed before the spherical ?-Al globules begin to lose their stability, but the ?-Al grains formed in the shot sleeve exceed the limit of spherical growth and therefore exhibit a dendritic morphology.

Ji, Shouxun; Wang, Yun; Watson, D.; Fan, Z.

2013-07-01

175

Microstructure and Creep Behavior of High-Pressure Die-Cast Magnesium Alloy AE44  

NASA Astrophysics Data System (ADS)

The microstructure and creep behavior of a high-pressure die-cast AE44 (Mg-4Al-4RE) alloy have been studied. The creep properties were evaluated at 423 K and 448 K (150 C and 175 C) under stresses in the range 90 to 110 MPa. The microstructures before and after creep were examined by transmission electron microscopy (TEM). After creep, AE44 exhibits anomalously high stress exponents ( n = 67 at 423 K [150 C] and n = 41 at 448 K [175 C]) and stress-dependant activation energies ranging from 221 to 286 kJ/mol. The dislocation substructure developed during creep is characterized by extensive nonbasal slip and isolated but well-defined subgrain boundaries. It is shown that the anomalously high stress exponents cannot be rationalized by the threshold stress approach that is commonly adopted in analyzing the creep behavior of dispersion-strengthened alloys or metal matrix composites. A comparison in creep resistance is also made between AE44 and AE42 (Mg-4Al-2RE).

Zhu, S. M.; Nie, J. F.; Gibson, M. A.; Easton, M. A.; Bakke, P.

2012-11-01

176

[Studies on application of pure titanium for cast plate].  

PubMed

Pure titanium produced by a commercial pure titanium casting system was studied for use as a cast plate for clinical application. The mechanical properties, elemental analysis, castability, adaptability of pure titanium and adhesion to denture base resin were investigated. The interfacial zone of the pure titanium castings was composed of a layered structure obtained by reaction with phosphate bonded Al2O3/SiO2 investment material. Vicher's hardness at 100 microns thick from the surface was higher than that in the inner part by oxidation. Cast pure titanium showed tensile strength, elongation and hardness close to those of the type III or IV dental gold alloy. The castability of pure titanium was lower than that of Co-Cr alloy and pure titanium castings also had large casting defects. Adaptability between pure titanium cast plate and the working model was satisfactory when reversible hydrocolloid impression material was used with heating-bath treatment in the refractory model. The tensile and compressive shear bonding strength of pure titanium to heat-curing or self-curing resin were similar to that of the Co-Cr alloy, and surface treatment using a solution containing 2-vol% 3-methacryloxypropyltrimethoxysilane produced a higher bonding strength than non-treatment, MKV treatment and 4-META treatment. These findings suggest that pure titanium castings produced by this system have suitable mechanical properties, adaptability and adhesion to denture base resin, and is available for cast plate in clinical application. PMID:2134765

Sakai, M

1990-06-01

177

An electron metallographic study of pressure die-cast commercial zincaluminium-based alloy ZA27  

Microsoft Academic Search

The microstructure of ZA27 pressure die-castings was examined by scanning and transmission electron microscopy after ageing\\u000a for 5 years at ambient temperatures. Solidification began with the formation of compact aluminium-rich ?? dendrites and tiny\\u000a rounded ?? particles, followed by the peritectic reaction whereby a zinc-rich ? phase formed around the edges of the primary\\u000a phases. The extremely high cooling rate

M. DURMAN; S. MURPHY

1997-01-01

178

Finite element analysis of filling stage in die-casting process using marker surface method and adaptive grid refinement technique  

Microsoft Academic Search

The marker surface method and the adaptive grid refinement technique have been applied to the three-dimensional (3-D) finite element analysis of the filling stage in the die-casting process. Especially, the marker surface plugging technique and the marker surface regeneration technique incorporated in the marker surface method have been proposed for the efficient analysis of 3-D practical problems. Through the marker

J. H. Jeong; D. Y. Yang

2004-01-01

179

Induction heating process of an AlSi aluminum alloy for semi-solid die casting and its resulting microstructure  

Microsoft Academic Search

During induction heating, the relationship between time and temperature must be controlled exactly to obtain a homogeneous temperature distribution over the entire cross-sectional area. Because the initial solid fraction in the semi-solid die casting (SDC) process is the main parameter to achieve a homogeneous flow behavior of the liquid and solid phases and to prevent macro-segregation effects in the SDC

H. K Jung; C. G Kang

2002-01-01

180

Fabrication of metal-matrix composites by the die-casting technique and the evaluation of their mechanical properties  

Microsoft Academic Search

To understand the possibility of the fabrication of metal-matrix composites (MMCs) by the die-casting technique, experimental data are presented for the injection of aluminum-alloy-based melts into fiber preforms composed of ?-alumina with silica binder. Preforms of volume fraction 15% were prepared from liquid slurry by vacuum-filtration processes. To find the optimal conditions for preform fabrication a series of experiments was

C. G. Kang; K. S. Yun

1996-01-01

181

Correlation of abrasive wear with microstructure and mechanical properties of pressure die-cast aluminum hard-particle composite  

Microsoft Academic Search

Aluminum hard particle composites were synthesized by the solidification processing technique and the composite melt was solidified\\u000a using gravity and pressure die castings. An aluminum-silicon alloy (A 332.1) has been used as the matrix and silicon carbide\\u000a particles (quantity: 10 wt pct, and size: 50 to 80 m) have been used as reinforcement for synthesis of the composite. The microstructure

S. Das; D. P. Mondal; G. Dixit

2001-01-01

182

Structure and formation mechanism of phosphate conversion coating on die-cast AZ91D magnesium alloy  

Microsoft Academic Search

Phosphate conversion coating, which is considered as an alternative to chromium conversion coating for improving the corrosion resistance of die-cast AZ91D magnesium alloy is studied. The structure and formation mechanism of the coating was investigated in details using ESEM\\/EDX, XRD, EPMA, ICP and electrochemical method. It was found that the conversion coating was composed of complex phosphate containing magnesium and

Wanqiu Zhou; Dayong Shan; En-Hou Han; Wei Ke

2008-01-01

183

A model of the interfacial heat-transfer coefficient for the aluminum gravity die-casting process  

Microsoft Academic Search

Interfacial heat-transfer coefficients were measured during the solidification of Al-Si alloys against coated die steel chills\\u000a with varying chill temperature, coating thickness and coating type. Two principal resistances to heat transfer across the\\u000a casting-chill interface were identified, namely, (1) the resistance to heat transfer of the coating itself and (2) the resistance\\u000a to heat transfer of a layer of gas,

C. P. Hallam; W. D. Griffiths

2004-01-01

184

The influence of manganese on the microstructure and mechanical properties of AZ31 gravity die cast alloys  

Microsoft Academic Search

Calculated phase diagrams for the MgAlZnMn system indicate that ?-Mn(Al) and Al8Mn5 can primarily crystallize during the solidification of Mn-modified AZ31. Both phases may act as potential heterogeneous nucleants for Mg grains and thus as potential grain refiners in the MgAl system. In this investigation three Mg3Al1Zn alloys with different Mn content were die cast and hot rolled at 450C.

T. Laser; M. R. Nrnberg; A. Janz; Ch. Hartig; D. Letzig; R. Schmid-Fetzer; R. Bormann

2006-01-01

185

Microstructure and mechanical properties of ZA104 (0.30.6Ca) die-casting magnesium alloys  

Microsoft Academic Search

In this paper, the microstructure of die-cast and slowly cooled specimens of two new experimental magnesium alloys (ZA104 + 0.3Ca and ZA104 + 0.6Ca) is examined. Microanalysis of specimens has revealed the presence of ?-Mg phase (matrix) and two intermetallic compounds containing calcium with different Zn\\/Al ratios. These compounds, which have a crystal structure close to that of ? phase

Z. Zhang; R. Tremblay; D. Dub

2004-01-01

186

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

187

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

188

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

Code of Federal Regulations, 2011 CFR

...false Applicability; description of the cast iron basis material subcategory. 466...PORCELAIN ENAMELING POINT SOURCE CATEGORY Cast Iron Basis Material Subcategory 466.20 Applicability; description of the cast iron basis material subcategory....

2011-07-01

189

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

Code of Federal Regulations, 2013 CFR

...false Applicability; description of the cast iron basis material subcategory. 466...PORCELAIN ENAMELING POINT SOURCE CATEGORY Cast Iron Basis Material Subcategory 466.20 Applicability; description of the cast iron basis material subcategory....

2013-07-01

190

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

Code of Federal Regulations, 2012 CFR

...false Applicability; description of the cast iron basis material subcategory. 466...PORCELAIN ENAMELING POINT SOURCE CATEGORY Cast Iron Basis Material Subcategory 466.20 Applicability; description of the cast iron basis material subcategory....

2012-07-01

191

Design and optimisation of runner and gating systems for the die casting of thin-walled magnesium telecommunication parts through numerical simulation  

Microsoft Academic Search

A well-designed runner and gating system is very important to secure good quality die castings through providing a homogenous mould filling pattern. Numerical simulation is a cost-effective tool in the design of runner and gating systems to visibly analyse the mould filling process. A thin-walled magnesium telecommunication part was selected to be hot chamber die cast and a numerical simulation

B. H Hu; K. K Tong; X. P Niu; I Pinwill

2000-01-01

192

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

193

Influence of Al addition on microstructure of die casting magnesium alloys  

Microsoft Academic Search

Purpose: In the following paper there have been the structure and properties of the MCMgAl9Zn1 magnesium cast alloy as-cast state and after a heat treatment presented. Design\\/methodology\\/approach: A casting cycle of alloys has been carried out in an induction crucible furnace using a protective salt bath Flux 12 equipped with two ceramic filters at the melting temperature of 75010C, suitable

L. A. Dobrza?ski a; T. Ta?ski; L. ?ek

2006-01-01

194

[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

195

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

196

The corrosion performance of die-cast magnesium alloy MRI230D in 3.5% NaCl solution saturated with Mg(OH){sub 2}  

SciTech Connect

The environmental behavior of die-cast magnesium alloy MRI230D designated for high-temperature applications was evaluated in comparison with regular AZ91D alloy. The microstructure examination was carried out using SEM, TEM, and X-ray diffraction analysis; the corrosion performance in 3.5% NaCl solution was evaluated by immersion test, salt spray testing, potentiodynamic polarization analysis, and stress corrosion behavior by Slow Strain Rate Testing (SSRT). Although the general corrosion resistance of MRI230D was slightly improved compared to that of AZ91D alloy its stress corrosion resistance was relatively reduced. The variations in the environmental behavior of the two alloys were mainly due to the differences in their chemical composition and microstructure after die casting. In particular, the differences were related to the reduced Al content in MRI230D and the addition of Ca to this alloy, which consequently affected its relative microstructure and electrochemical characteristics. - Research Highlights: {yields}Corrosion and SCC resistance of a new Mg alloy MRI230D was evaluated vs. regular AZ91D. {yields}MRI230D has a minor advantage in corrosion performance compared with AZ91D. {yields}The SCC resistance of MRI230D by SSRT analysis was relatively reduced. {yields}The reduced SCC resistance of MRI230D was due to the detrimental effect of Ca on ductility.

Aghion, E., E-mail: egyon@bgu.ac.il; Lulu, N.

2010-11-15

197

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

198

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 m 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

199

Novel through-die connections for MEMS applications  

NASA Astrophysics Data System (ADS)

Novel through-die front-to-back connections for MEMS applications are described. Large diameter (~100 ?m diameter) front-to-back through-die connections have been studied previously for MEMS applications. Multi-level through-die hole structures are proposed here to overcome problems of large diameter through-die holes (lesser front-side active area) and facilitate new applications. Two-level versions of such through-die holes comprise of a small front-side hole (<1 ?m diameter) and a large back-side hole (~100 ?m diameter), or vice versa. Alternatively, multiple small holes from one side can connect to a large hole from the other side. Multiple concentric holes from one surface can be fabricated with appropriate spacer technology. Two-level through-die structures in silicon have been designed, fabrication processes developed, and the resulting structures characterized. New CMP based patterning techniques have been developed for sidewall films on through-die wafers. Two-level through-die holes have been fabricated with 100 ?m diameter hole in the back and 5 to 30 ?m diameter holes in the front-side with a pitch from 300 ?m to 1000 ?m. Through-die hole sidewall conductive coatings have been accomplished with CVD Tungsten and in-situ doped LPCVD Polysilicon. Two-level through-die holes have many potential applications, including low impedance ground connections, on-die power/ground distribution, on-die Faraday shielding, on-chip CMOS and MEMS integration, 3D MEMS devices, micro-fluidics, and 3D integration.

Kommera, Swaroop; Woods, Wayne; Krusius, J. Peter

2003-01-01

200

Microstructure-properties correlation of pressure die cast eutectic aluminum-silicon alloys for escalator steps (Part I)  

SciTech Connect

This paper is a study of the roles of strontium as a modifier and titanium as a refiner of the Al-12%Si commercial alloy for escalator steps processed by a hot-chamber pressure-die casting method. Specifically, two objectives were pursued. First, the detection of the level at which the modifier and the refiner become effective in altering the relevant microstructural parameters, namely, the volume fraction, grain size and shape of proeutectic phases. Second, investigation of the morphology of the eutectic matrix.

Asensio-Lozano, J. [Department of Materials Science and Metallurgical Engineering, The School of Mines, University of Oviedo, 13 Independence St., Oviedo, E-33004 Asturias (Spain)]. E-mail: jasensio@etsimo.uniovi.es; Suarez-Pena, B. [Department of Materials Science and Metallurgical Engineering, Technical School of Industrial Engineering, University of Oviedo, Viesques University Campus, Carretera de Castiello de Bernueces, s/n, Gijon, E-33203 Asturias (Spain)

2006-04-15

201

Microstructure and second-phase particles in low- and high-pressure die-cast magnesium alloy AM50  

Microsoft Academic Search

The microstructure and phase composition of low-pressure die-cast (LPDC) and high-pressure diecast (HPDC) magnesium alloy\\u000a AM50 were examined by transmission electron microscopy (TEM) techniques in combination with optical microscopy, scanning electron\\u000a microscopy (SEM), and electron-probe microanalysis (EPMA). It has been established that the dimensions and morphology of the\\u000a constituent phases (?-Mg solid solution, Mg17Al12, and Al8Mn5) depend on the processing

Val Y. Gertsman; Jian Li; Su Xu; James P. Thomson; Mahi Sahoo

2005-01-01

202

Thermal and metallographic characteristics of the Al20% 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 Al20% Si cylinder block at a cooling rate of 1C\\/s. The liquidus temperature was approximately 6912.2C, the nucleation temperature of the AlSi eutectic was approximately 567.11.9C and the nucleation temperature of the Cu- and Mg-enriched eutectic was approximately 513.61.4C. The fraction solid increases linearly from 0 to

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

2008-01-01

203

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

204

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

205

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

206

25 CFR 301.4 - Application of dies.  

Code of Federal Regulations, 2010 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...

2010-04-01

207

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.

2012-02-06

208

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

209

Finite element analysis of filling stage in die-casting process using marker surface method and adaptive grid refinement technique  

NASA Astrophysics Data System (ADS)

The marker surface method and the adaptive grid refinement technique have been applied to the three-dimensional (3-D) finite element analysis of the filling stage in the die-casting process. Especially, the marker surface plugging technique and the marker surface regeneration technique incorporated in the marker surface method have been proposed for the efficient analysis of 3-D practical problems. Through the marker surface plugging technique, new parts of marker surface are effective lycreated in order to eliminate the gaps between the parts of marker surface or between the edge of marker surface and cavity wall. By using the marker surface regeneration technique, the marker surface including a great number of marker elements is recreated on the basis of its original shape in order to decrease the number of marker elements and computational time. A3-D example used as the benchmark test and a typical industrial problem of the die-casting process have been analysed. The numerical results have been in good agreement with the experimental results and the efficiency of the adaptive grid refinement technique has been verified. It has been shown that the proposed techniques incorporated in the marker surface method and the adaptive grid refinement technique can be effectively applied to general industrial problems.

Jeong, J. H.; Yang, D. Y.

2004-01-01

210

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

211

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

212

Surface compositional inhomogeneity and subsurface microstructures in a thin-walled AZ91D plate formed by hot-chamber die casting  

Microsoft Academic Search

The accumulation of alloying elements and iron impurities in thin-wall AZ91D plate (300mm240mm1.4mm) formed by hot-chamber die casting were investigated. Mold filling and temperature variation during casting were computationally simulated. The concentrations of alloy elements were examined using a glow discharge optical emission spectrometer (GD-OES). Glancing angle X-ray diffraction (GAXRD) and scanning electron microscopy (SEM) were employed to elucidate the

C. Y. Cho; J. Y. Uan; H. J. Lin

2005-01-01

213

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

214

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

215

Effect of the use of die spacer on the marginal fit of copings cast in NiCr, NiCrBe and commercially pure titanium.  

PubMed

The goal of this study was to evaluate the effect of using die spacers on the marginal fit of NiCr (M1) and NiCrBe (M2) alloys and commercially pure titanium (cpTi) (M3) copings cast by the lost wax technique. Using a metal matrix, 45 resin added extra hard type IV stone models were obtained for the fabrication of wax patterns under the following conditions: no die spacer (A), with one die spacer layer (B) and with two die spacer layers (C), with five repetitions for each condition (alloy x die). Each die was waxed and the wax patterns were invested as per manufacturer's instructions. Three wax patterns were embedded in each casting ring, each corresponding to one of the conditions. Each coping, seated to the metal matrix by a seating pressure standardizing device (SPSD), was taken to an optical microscope for measurement of marginal discrepancy. The obtained data (microm) were analyzed statistically by ANOVA and Tukey' test (a=5%). There was statistically significant difference (p<0.05) among the materials (M1=110.67; M2=130.33 and M3=148.33). Regarding the use of the die spacer, there was a statistically significant difference (p<0.05) among the three conditions (A=162.00; B=131.06 and C=96.67). It was concluded that there is less marginal discrepancy with two die spacer layers. PMID:18176714

Soriani, Natrcia Carreira; Leal, Mnica Barbosa; Paulino, Silvana Maria; Pagnano, Valria Oliveira; Bezzon, Osvaldo Luiz

2007-01-01

216

40 CFR 63.1500 - Applicability.  

...subpart applicable to area sources. (f) An aluminum die casting facility, aluminum foundry, or aluminum extrusion...subpart or any other subpart. In the case of an aluminum die casting facility, aluminum foundry, or aluminum...

2014-07-01

217

40 CFR 63.1500 - Applicability.  

Code of Federal Regulations, 2012 CFR

...subpart applicable to area sources. (f) An aluminum die casting facility, aluminum foundry, or aluminum extrusion...subpart or any other subpart. In the case of an aluminum die casting facility, aluminum foundry, or aluminum...

2012-07-01

218

40 CFR 63.1500 - Applicability.  

Code of Federal Regulations, 2011 CFR

...subpart applicable to area sources. (f) An aluminum die casting facility, aluminum foundry, or aluminum extrusion...subpart or any other subpart. In the case of an aluminum die casting facility, aluminum foundry, or aluminum...

2011-07-01

219

40 CFR 63.1500 - Applicability.  

Code of Federal Regulations, 2010 CFR

...subpart applicable to area sources. (f) An aluminum die casting facility, aluminum foundry, or aluminum extrusion...subpart or any other subpart. In the case of an aluminum die casting facility, aluminum foundry, or aluminum...

2010-07-01

220

40 CFR 63.1500 - Applicability.  

Code of Federal Regulations, 2013 CFR

...subpart applicable to area sources. (f) An aluminum die casting facility, aluminum foundry, or aluminum extrusion...subpart or any other subpart. In the case of an aluminum die casting facility, aluminum foundry, or aluminum...

2013-07-01

221

An Application of Trapped-Air Analysis to Large Complex High-Pressure Magnesium Casting  

SciTech Connect

The usual method for simulating die-castings consists of a solidification analysis of the casting process - a computer calculation of heat transfer between the casting and the die components. The use of cyclic simulations, coupled with the geometric accuracy of the finite element method, has advanced this procedure to the point where it is routinely used for reliable prediction of shrinkage defects in die-castings. Filling analysis is also routinely used to get a glimpse of cavity filling and ensures that overflows are at their most effective location. When coupled with heat transfer, a filling analysis is also very effective in demonstrating the effects of heat loss in the fluid and how it consequentially can negatively affect filling.

Prindiville, J; Lee, S; Gokhale, A

2004-07-08

222

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

223

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

Code of Federal Regulations, 2010 CFR

...EFFLUENT GUIDELINES AND STANDARDS IRON AND STEEL MANUFACTURING POINT...CATEGORY Continuous Casting Subcategory 420...applicable to discharges and to the introduction...from the continous casting of molten steel into...

2010-07-01

224

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

Code of Federal Regulations, 2013 CFR

...EFFLUENT GUIDELINES AND STANDARDS IRON AND STEEL MANUFACTURING POINT...CATEGORY Continuous Casting Subcategory 420...applicable to discharges and to the introduction...from the continous casting of molten steel into...

2013-07-01

225

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

Code of Federal Regulations, 2012 CFR

...EFFLUENT GUIDELINES AND STANDARDS IRON AND STEEL MANUFACTURING POINT...CATEGORY Continuous Casting Subcategory 420...applicable to discharges and to the introduction...from the continous casting of molten steel into...

2012-07-01

226

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

Code of Federal Regulations, 2011 CFR

...EFFLUENT GUIDELINES AND STANDARDS IRON AND STEEL MANUFACTURING POINT...CATEGORY Continuous Casting Subcategory 420...applicable to discharges and to the introduction...from the continous casting of molten steel into...

2011-07-01

227

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

228

The effect of microstructure on the thermal fatigue resistance of investment cast and wrought AISI H13 hot work die steel  

SciTech Connect

Variable thickness plate investment castings of AISI H13 hot work die steel were pour 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 steel were heat treated and characterized similarly for comparison. Microstructural differences were observed in as-cast samples poured to different section thicknesses. Dendrite cell size and carbide morphology constituted the most prominent microstructural differences observed. After a full heat treatment, however, 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 designed and built to correlate the heat checking susceptibility of AISI H13 steel to its processing and consequent microstructural condition. Surface hardness decreased significantly with thermal cycling, and heat checking was noticed 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; however, the heat-treat cast and as-cast H13 tool steel (made from standard grade wrought H13 tool steel) provided comparable resistance to heat checking in terms Of area fraction of heat checking and maximum crack length.

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

1995-07-01

229

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

230

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.; Cceres, Carlos H.; Easton, Mark A.

2014-08-01

231

Freeze-cast hydroxyapatite scaffolds for bone tissue engineering applications.  

PubMed

Freeze casting of aqueous suspensions was investigated as a method for preparing porous hydroxyapatite (HA) scaffolds for eventual application to bone tissue engineering. Suspensions of HA particles (10-20 volume percent) were frozen unidirectionally in a cylindrical mold placed on a cold steel substrate (-20 degrees C). After sublimation of the ice, sintering for 3 h at 1350 degrees C produced constructs with dense HA lamellae, with porosity of approximately 50%, and inter-lamellar pore widths of 5-30 microm. These constructs had compressive strengths of 12 +/- 1 MPa and 5 +/- 1 MPa in the directions parallel and perpendicular to the freezing direction, respectively. Manipulation of the microstructure was achieved by modifying the solvent composition of the suspension used for freeze casting. The use of water-glycerol mixtures (20 wt% glycerol) resulted in the production of constructs with finer pores (1-10 microm) and a larger number of dendritic growth connecting the HA lamellae, and higher strength. On the other hand, the use of water-dioxane mixtures (60 wt% dioxane) resulted in a cellular-type microstructure with larger pores (90-110 microm). The mechanical response showed high strain tolerance (5-10% at the maximum stress), high strain for failure (>20%) and sensitivity to the loading rate. The favorable mechanical behavior of the porous constructs, coupled with the ability to modify their microstructure, indicates the potential of the present freeze casting route for the production of porous scaffolds for bone tissue engineering. PMID:18458369

Fu, Qiang; Rahaman, Mohamed N; Dogan, Fatih; Bal, B Sonny

2008-06-01

232

Comparative study of creep of the die-cast Mg-alloys AZ91, AS21, AS41, AM60 and AE42  

Microsoft Academic Search

The creep resistance of five high-purity die-cast MgAl-alloys was investigated in uniaxial compression at temperatures from 70 to 150C. The evolution of deformation resistance under creep conditions is described as a function of strain ?. The work hardening in primary creep determines the times for creep by strains <0.01. Among the investigated alloys AZ91 has the highest creep resistance with

W Blum; P Zhang; B Watzinger; B. v Grossmann; H. G Haldenwanger

2001-01-01

233

Constitutive prediction and dependence of tensile properties of high-pressure die-cast AM60B and AZ91D magnesium alloy on microporosity  

Microsoft Academic Search

The effect of micro-voids on the tensile property of high-pressure die-cast AM60B and AZ91D magnesium alloy was investigated\\u000a through systematic experimental approaches, with a constitutive prediction on the load carrying capacity and strain-related\\u000a factors. The strain rate sensitivity was measured through the incremental strain rate change test, and the microporosity was\\u000a measured from a comparison between the area of the

Choong Do Lee

2006-01-01

234

Influence of heat treatment on degradation behavior of bio-degradable die-cast AZ63 magnesium alloy in simulated body fluid  

Microsoft Academic Search

The effects of hybrid aging and solution treatments on the degradation of bio-degradable die-cast AZ63 magnesium alloy in 371C Tyrode's simulated body fluid have been investigated. The heat treatment is observed to alter the microstructure of the alloy. The amount of ?-Mg17Al2 precipitates is larger and their distribution is more homogeneous. The homogeneous microstructure enhances the corrosion resistance of the

Chenglong Liu; Yunchang Xin; Guoyi Tang; Paul K. Chu

2007-01-01

235

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

236

Relationship Between the 3D Porosity and ?-Phase Distributions and the Mechanical Properties of a High Pressure Die Cast AZ91 Mg Alloy  

NASA Astrophysics Data System (ADS)

Currently, most magnesium lightweight components are fabricated by casting as this process is cost effective and allows forming parts with complex geometries and weak textures. However, cast microstructures are known to be heterogeneous and contain unpredictable porosity distributions, which give rise to a large variability in the mechanical properties. This work constitutes an attempt to correlate the microstructure and the mechanical behavior of a high pressure die cast (HPDC) Mg AZ91 alloy, aimed at facilitating process optimization. We have built a stairway-shaped die to fabricate alloy sections with different thicknesses and, thus, with a range of microstructures. The grain size distributions and the content of ?-phase (Mg17Al12) were characterized by optical and electron microscopy techniques as well as by electron backscatter diffraction (EBSD). The bulk porosity distribution was measured by 3D computed X-ray microtomography. It was found that the through-thickness microhardness distribution is mostly related to the local area fraction of the ?-phase and to the local area fraction of the pores. We correlate the tensile yield strength to the average pore size and the fracture strength and elongation to the bulk porosity volume fraction. We propose that this empirical approach might be extended to the estimation of mechanical properties in other HPDC Mg alloys.

Biswas, Somjeet; Sket, Federico; Chiumenti, Michele; Gutirrez-Urrutia, Ivn; Molina-Aldaregua, Jon M.; Prez-Prado, Maria Teresa

2013-09-01

237

Application of cast gamma TiAl for automobiles  

Microsoft Academic Search

Studies of cast gamma TiAl applied for engine valves and turbocharger confirmed excellent performances. The durability of TiAl valves was also proven. Two cast gamma TiAl alloys were developed for the engine valves and the turbine wheels of turbochargers. New precision casting process of LEVICAST and induction brazing process of the gamma TiAl and alloy steels were proposed as advanced

T. Noda

1998-01-01

238

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

239

Effect of Nd on the microstructure, mechanical properties and corrosion behavior of die-cast Mg4Al-based alloy  

Microsoft Academic Search

Die-cast Mg4Al0.4MnxNd (x=0, 1, 2, 4 and 6wt.%) magnesium alloys were prepared successfully and influences of Nd on the microstructure, mechanical properties and corrosion behavior of the Mg4Al0.4Mn alloy have been investigated. The results showed that with the addition of Nd binary Al2Nd phase and Al11Nd3 phase, which mainly aggregated along the grain boundaries, were formed, and the relative ratio

Jinghuai Zhang; Jun Wang; Xin Qiu; Deping Zhang; Zheng Tian; Xiaodong Niu; Dingxiang Tang; Jian Meng

2008-01-01

240

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

241

Determination of particle concentration rankings by spatial mapping of particle surface area, number, and mass concentrations in a restaurant and a die casting plant.  

PubMed

Measurements using several exposure metrics were carried out in a restaurant and a die casting plant to compare the spatial distributions of particle surface area (SA), number, and mass concentrations and rank exposures in different areas by those metrics. The different exposure metrics for incidental nanoparticle and fine particle exposures were compared using the concentration rankings, statistical differences between areas, and concentration ratios between different areas. In the die casting plant, area concentration rankings and spatial distributions differed by the exposure metrics chosen. Surface area and fine particle number concentrations were greatest near incidental nanoparticle sources and were significantly different between three areas. However, mass and coarse particle number concentrations were similar throughout the facility, and rankings of the work areas based on these metrics were different from those of SA and fine number concentrations. In the restaurant, concentrations in the kitchen for all metrics except respirable mass concentration were significantly greater than in the serving area, although SA and fine particle number concentrations showed larger differences between the two areas than either the mass or coarse particle number concentrations. Thus, the choice of appropriate exposure metric has significant implications for exposure groupings in epidemiologic and occupational exposure studies. PMID:20526949

Park, Ji Young; Ramachandran, Gurumurthy; Raynor, Peter C; Olson, Gregory M

2010-08-01

242

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

243

3D characterization of intermetallics in a high pressure die cast Mg alloy using focused ion beam tomography  

SciTech Connect

The degree of spatial interconnection of the Mg{sub 17}Al{sub 12} ({beta}-phase) intermetallic in a Mg-9Al-1Zn alloy was assessed through serial sectioning at the centre and near a corner in a casting cross-section. The three dimensional reconstructions showed that the intermetallics were profusely interconnected forming a scaffold-like network over the entire cross-section, but especially near the casting surface. The scale and degree of the interconnection appeared determined by the local concentration of large dendritic grains injected from the shot sleeve. The volume fractions of intermetallics obtained through the 3D reconstruction indicated a higher content of {beta}-phase at the corner regions in comparison with the core. The volume fractions obtained by FIB were consistent with theoretical and experimental values obtained using other techniques.

Nagasekhar, A.V. [ARC Centre of Excellence for Design in Light Metals, Materials Engineering, University of Queensland, Brisbane, QLD 4072 (Australia); Caceres, C.H., E-mail: c.caceres@uq.edu.au [ARC Centre of Excellence for Design in Light Metals, Materials Engineering, University of Queensland, Brisbane, QLD 4072 (Australia); Kong, C. [Electron Microscope Unit, UNSW Analytical Centre, University of New South Wales, Sydney, NSW 2052 (Australia)

2010-11-15

244

Assessment of skin dose modification caused by application of immobilizing cast in head and neck radiotherapy.  

PubMed

Skin dose assessment for radiotherapy patients is important to ensure that the dose received by skin is not excessive and does not cause skin reactions. Immobilizing casts may have a buildup effect, and can enhance the skin dose. This study has quantified changes to the surface dose as a result of head and neck immobilizing casts. Medtech and Renfu casts were stretched on the head of an Alderson Rando-Phantom. Irradiation was performed using 6 and 15 MV X-rays, and surface dose was measured by thermoluminescence dosimeters. In the case of 15MV photons, immobilizing casts had no effect on the surface dose. However, the mean surface dose increase reached up to 20% when 6MV X-rays were applied. Radiation incidence angle, thickness, and meshed pattern of the casts affected the quantity of dose enhancement. For vertical beams, the surface dose increase was more than tangential beams, and when doses of the points under different areas of the casts were analysed separately, results showed that only doses of the points under the thick area had been changed. Doses of the points under the thin area and those within the holes were identical to the same points without immobilizing casts. Higher dose which was incurred due to application of immobilizing casts (20%) would not affect the quality of life and treatment of patients whose head and neck are treated. Therefore, the benefits of head and neck thermoplastic casts are more than their detriments. However, producing thinner casts with larger holes may reduce the dose enhancement effect. PMID:24964872

Soleymanifard, Shokouhozaman; Toossi, Mohammad Taghi Bahreyni; Khosroabadi, Mohsen; Noghreiyan, Atefeh Vejdani; Shahidsales, Soodabeh; Tabrizi, Fatemeh Varshoee

2014-09-01

245

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

246

Fastcast: Integration and application of rapid prototyping and computational simulation to investment casting  

SciTech Connect

The emergence of several rapid prototyping and manufacturing (RP and M) technologies is having a dramatic impact on investment casting. While the most successful of the rapid prototyping technologies are almost a decade old, relatively recent process advances in their application have produced some remarkable success in utilizing their products as patterns for investment castings. Sandia National Laboratories has been developed highly coupled experimental and computational capabilities to examine the investment casting process with the intention of reducing the amount of time required to manufacture castings, and to increase the quality of the finished product. This presentation will begin with process aspects of RP and M pattern production and handling, shell fabrication, burnout, and casting. The emphasis will be on how the use of Stereolithography (SL) or Selective Laser Sintered (SLS) patterns differs from more traditional wax pattern processes. Aspects of computational simulation to couple design, thermal analysis, and mold filling will be discussed. Integration of these topics is probably the greatest challenge to the use of concurrent engineering principles with investment casting. Sandia has conducted several experiments aimed at calibrating computer codes and providing data for input into these simulations. Studies involving materials as diverse as stainless steel and gold have been conducted to determine liquid metal behavior in molds via real time radiography. The application of these experiments to predictive simulations will be described.

Maguire, M.C.; Baldwin, M.D.; Atwood, C.L.

1996-09-01

247

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

Federal Register 2010, 2011, 2012, 2013

...related to the production of aluminum die castings. New information revealed that...or directly competitive aluminum die castings produced by the subject firm have...regarding their purchases of aluminum die castings during the relevant period....

2011-02-02

248

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

249

Acquired Localized Hypertrichosis Induced by Internal Fixation and Plaster Cast Application  

PubMed Central

Hypertrichosis refers to increased vellus hair growth and is independent to androgen excess. The acquired localized hypertrichosis (ALH) is one of the typical hypertrichosis, which mainly results from chronic irritation, inflammation, friction, and occlusion by plaster of Paris. Here, we report a young boy who had ALH on his right hand following a closed fracture with internal fixation and plaster cast application. The case is unusual because the hairy area is limited to the operative region of internal fixation. We suggest that the local vascular changes and skin inflammation induced by internal fixation and plaster cast application may be associated with ALH. PMID:24003283

Yang, Yang; Ma, Hui-Yong; Jia, Chi-Yu; Li, Ting-Hui

2013-01-01

250

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

251

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

252

Cast CF8C-Plus Stainless Steel for Turbocharger Applications  

SciTech Connect

The purpose of this Cooperative Research and Development Agreement (CRADA) project is to provide the critical test data needed to qualify CF8C-Plus cast stainless steel for commercial production and use for turbocharger housings with upgraded performance and durability relative to standard commercial cast irons or stainless steels. The turbocharger technologies include, but are not limited to, heavy-duty highway diesel engines, and passenger vehicle diesel and gasoline engines. This CRADA provides additional critical high-temperature mechanical properties testing and data analysis needed to quality the new CF8C-Plus steels for turbocharger housing applications.

Maziasz, P.J.; Shyam, A.; Evans, N.D.; Pattabiraman, K. (Honeywell Turbo Technologies

2010-06-30

253

Numerical simulation of the interface molten metal air in the shot sleeve chambre and mold cavity of a die casting machine  

NASA Astrophysics Data System (ADS)

The objective of this study relates to the numerical simulation of the free surface during the two-dimensional flow and solidification of aluminum in the horizontal cylinder and mold cavity of the high pressure die casting HPDC machine with cold chamber. The flow is governed by the Navier-Stokes equations (the mass and the momentum conservations) and solved in the two phase's liquid aluminum and air. The tracking of the free surface is ensured by the VOF method. The equivalent specific heat method is used to solve the phase change heat transfer problem in the solidification process. Considering the displacement of the plunger, the geometry of the problem is variable and the numerical resolution uses a dynamic grid. The study examines the influence of the plunger speed on the evolution of the interface aluminum liquid-air profile, the mass of air imprisoned and the stream function contours versus time. Filling of a mold is an essential part of HPDC process and affects significantly the heat transfer and solidification of the melt. For this reason, accurate prediction of the temperature field in the system can be achieved only by including simulation of filling in the analysis.

Korti, Abdel Illah Nabil; Abboudi, Said

2011-11-01

254

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

255

Development of cast ferrous alloys for Stirling engine application  

NASA Technical Reports Server (NTRS)

Low cost cast ferrous base alloys that can be used for cylinder and regenerator housing components of the Stirling engine were investigated. The alloys must meet the requirements of high strength and thermal fatigue resistance to approximately 1500 F, compatibility and low permeability with hydrogen, good elevated temperature oxidation/corrosion resistance, and contain a minimum of strategic elements. The phase constituents of over twenty alloy iterations were examined by X-ray diffraction. These alloy candidates were further screened for their tensile and stress rupture strength and surface stability in air at 1450 and 1600 F, respectively. Two alloys, NASAUT 1G (Fe-10Mn-20Cr-1.5C-1.0Si) and NASAUT 4G (Fe-15Mn-12Cr-3Mo-1.5C-1.0Si-1.0Nb), were chosen for more extensive elevated temperature testing. These alloys were found to exhibit nearly equivalent elevated temperature creep strength and oxidation resistance. Silicon present in these alloys at the 1 w/o level permitted the achievement of oxide scale adherence to 1600 F without loss of strength (or ductility) as was noted for equivalent additions of aluminum.

Lemkey, F. D.

1982-01-01

256

A three-dimensional boundary element approach to confined free-surface flow as applied to die casting  

Microsoft Academic Search

A three-dimensional boundary-element method is proposed for the numerical simulation of confined free surface flow problems. Although the method is applicable to viscous and inviscid flows, the present formulation will be limited to potential flow, including transient and nonlinear waves in cavities of general shape. The emphasis in this study, however, will be on the flow driven by a plunger

Roger E. Khayat

1998-01-01

257

Quality index chart for different alloys and temperatures: a case study on aluminium die-casting alloys  

Microsoft Academic Search

The possibility of developing an analytical quality index chart for applications above room temperature valid for different alloys is explored. The testing temperature and the chemical composition of the material are incorporated into the analysis through their respective effects on the material's strain hardening rate and yield strength. The resulting quality index chart has been used to compare the performance

C. H Cceres; M Makhlouf; D Apelian; L Wang

2001-01-01

258

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

259

Evaluation and comparison of casting materials in forensic sciences Applications to tool marks and foot\\/shoe impressions  

Microsoft Academic Search

Elastomeric products used for casting toolmarks and footprints have been tested as to their dimensional stability, elastical memory, viscosity and application time. A survey of products used by different police forces in Europe has also shown the perceived advantages or drawbacks of 13 different products. New products have been tested and adapted for footmark casting. Side by side comparison of

E. Du Pasquier; J. Hebrard; P. Margot; M. Ineichen

1996-01-01

260

Urinary casts  

MedlinePLUS

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

261

Steel castings by the electroslag casting technique  

NASA Astrophysics Data System (ADS)

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

Sikka, V. K.; Mitchell, A.

1984-10-01

262

Steel castings by the electroslag casting technique  

SciTech Connect

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

Sikka, V.K.; Mitchell, A.

1984-10-01

263

Development of simultaneous CAE system for design and production of casting parts  

SciTech Connect

Recently, it has become a requirement to produce high quality automotive castings with more complicated and thinner shapes with lower cost. The authors have developed a simultaneous CAE system that makes it possible to consider and optimize various demands of functional design and casting design simultaneously in the conceptual stage. It has several functions and features as follows: (1) functional design of casting part by stress analysis; (2) predicting flow characteristics and heat transfer to die when molten metal is poured into a die; (3) predicting shrinkage of cast iron in solidification after filling up; (4) predicting material properties of cast iron; (5) using common CAD data for functional design and casting design. This paper presents the numerical analysis methods, system configuration and application example of the simultaneous CAE system.

Maeda, M.; Yamamoto, T.; Keta, M.; Otsuka, Y.; Tokui, M. [Toyota Motor Corp., Aichi (Japan)

1995-12-31

264

Research of semi solid casting of iron  

Microsoft Academic Search

One result of the research on semi solid casting of iron is the development of parts having qualities that combine the superior material properties of ferrous alloy with the dimensional accuracy of aluminum die-cast parts. Iron material composition, molding methods using optimal billet heating speeds and copper die materials and methods for the continuous casting of raw material billets were

Masayuki Tsuchiya; Hiroaki Ueno; Isamu Takagi

2003-01-01

265

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

266

Comment on the reported fiber attenuations in the visible regime in 'Fabrication of glass photonic crystal fibers with a die-cast process'  

SciTech Connect

We comment on the recent paper by Zhou et al. [Appl. Opt.45, 4433 (2006)APOPAI0003-693510.1364/AO.45.004433], in which transmission losses of 0.2-0.3 dB/m were claimed across the wavelength range 420-900 nm in a high-index (nd=1.80518 at 587.6 nm) SF6 glass-based photonic crystal fiber fabricated by novel die-cast technique. If confirmed, these losses are at least 1 order of magnitude lower than previous reported losses of SF6 photonic crystal fibers from other fabrication approaches. Here we present a statistic survey on the relationship between the refractive index and the bulk material attenuation, based on a large number of commercial Schott optical glasses with the nd ranging between 1.40 and 2.05. It shows that the loss of a high-index (nd=1.80) glass optical fiber should be at the levels of 10-50 dB/m at 420 nm and 1-10 dB/m at 500 nm, respectively. Moreover, the material attenuation of such a high-index glass fiber should intrinsically show a large decay, from 10-50 dB/m at 420 nm to the level of 1 dB/m at 700 nm, which arises from the tail on the UV absorption edge of the high-index glass extending to the visible region. Therefore, we conclude that: (1) the low loss of 0.2-0.3 dB/m reported in the cited paper is abnormally one or two magnitudes lower than the material attenuation that a high-index (nd=1.80) glass optical fiber should have in the range between 420 and 500 nm and that (2) the flat loss curve between 420 and 700 nm in the cited paper deviates greatly from the intrinsic behavior of a high-index (nd=1.80) glass fiber.

Feng Xian; Loh, Wei H.; Richardson, David J

2008-10-01

267

Influence of casting methods on marginal and internal discrepancies of complete cast crowns.  

PubMed

The relationship between the application of die-spacer prior to wax pattern fabrication and metal removal from the inner surface of the casting on marginal and internal discrepancies of complete cast crowns was evaluated. One hundred and twenty complete crowns were cast with palladium-silver alloy melted by gas-oxygen torch or electrical resistance and cast with a centrifuge casting machine. After casting, the crowns were seated on each type of different marginal configuration dies (90-degree shoulder, 20-degree beveled shoulder, and 45-degree chamfered shoulder) with a static load of 90 N during 1 min. Evaluation of the marginal fit of the specimens was made using a digital micrometer. The crowns were embedded in acrylic resin and longitudinally sectioned to verify the internal discrepancy that occurred in lateral and occlusal interfaces with a digital micrometer. The data were submitted to ANOVA and Tukey's test with a significance level of 5%. The best marginal and inner fits were obtained with the gas-oxygen torch source. The 45-degree chamfered shoulder showed the best marginal and inner fit, and better internal relief was obtained in the crowns abraded with 50 microm Al2O3 particles. PMID:15776195

Milan, Fbio Machado; Consani, Simonides; Correr Sobrinho, Loureno; Sinhoreti, Mario Alexandre Coelho; Sousa-Neto, Manoel D; Knowles, Jonathan C

2004-01-01

268

OF INVESTMENT CASTS ALLOYS  

Microsoft Academic Search

Deformation and cracking of cast parts due to thermal stresses and hindered shrinkage are fre- quent casting defects. Whereas the numerical simulation of mold filling and solidification are already state of the art, applications of a thermal stress analysis are rarely found. The present study reveals how a combined thermo-mechanical model can be used for the investment casting process by

L. C. Wrker; M. Fackeldey; P. R. Sahm; B. G. Thomas

269

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

270

a Study on the Failure Analysis of Cast Iron Brake Blocks that are Used for Railway Applications  

Microsoft Academic Search

In order to clarify the cracking and failure behavior of gray cast iron brake blocks that are used for the railway applications, macro- and micro observations regarding the cracks and the micro-structure of the used brake blocks were examined. Three brake blocks, which have different degrees of hot spots and cracking during the actual application, were selected for testing. In

Chang-Min Suh; Byung-Won Hwang; Woo-Ho Bae

2006-01-01

271

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

272

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

Federal Register 2010, 2011, 2012, 2013

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

2010-04-19

273

Structure and transition of eutectic (Mg,Al) 2Ca Laves phase in a die-cast MgAlCa base alloy  

Microsoft Academic Search

The crystal structure of a eutectic (Mg,Al)2Ca Laves phase in as-cast AXJ530 (Mg5Al3Ca0.15Sr) was identified as C36 by electron diffraction analysis. The C36 phase transformed to C15(Al2Ca) during annealing at 573 K. The orientation relationship for the C15 and C36 phases is reported.

A. Suzuki; N. D. Saddock; J. W. Jones; T. M. Pollock

2004-01-01

274

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

275

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

Microsoft Academic Search

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: ;\\u000a*\\u0009Little proof of consistency

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

2012-01-01

276

The application of defect maps in the process modeling of single-crystal investment casting  

NASA Astrophysics Data System (ADS)

Because single-crystal components are Jmrd to cast, accurate models of the casting parameters can help to reduce the scrap rate and lower costs. A defect map, which plots the occurrence of defects based on the temperature gradient and the solidification rate, can be used as a performance criterion in process modeling. This article describes the use of defect maps in the investment casting of a single-crystal turbine blade.

Tu, John S.; Kelly Foran, R.

1992-06-01

277

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

278

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

NASA Astrophysics Data System (ADS)

In simulation of solidification processes, an open issue is the concurrent modelling of fluid flow and solid mechanics. This is critical for the prediction of cracks formed in solidified regions during the filling stage of ingot casting, or in the mould during continuous casting. The proposed approach consists of a partitioned two-step resolution strategy.

Bellet, Michel; Boughanmi, Okba; Fidel, Grgory

2012-07-01

279

Large shaped parts of melt cast BSCCO for applications in electrical engineering  

Microsoft Academic Search

A melt casting process (MCP) that is tailor made for BSCCO, especially for the 2212 phase, is described. It is reported that melt casting offers an easy access to a variety of different shapes and sizes. The properties of the material obtained by MCP have been significantly improved by admixing strontium sulphate. Jc values superior to those of sintered ceramics

J. Bock; H. Bestgen; S. Elschner; E. Preisler

1993-01-01

280

The improvement of aluminium casting process control by application of the new CRIMSON process  

Microsoft Academic Search

All The traditional foundry usually not only uses batch melting where the aluminium alloys are melted and held in a furnace for long time, but also uses the gravity filling method in both Sand Casting Process (SCP) and Investment Casting Process (ICP). In the gravity filling operation, the turbulent behaviour of the liquid metal causes substantial entrainment of the surface

X Dai; M Jolly; B Zeng

2012-01-01

281

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

National Technical Information Service (NTIS)

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 H...

D. Schwam, J. F. Wallace, Q. Zhou

2002-01-01

282

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 colismallest-sized water-borne bacteria) test confirm the possibility of separation through this membrane

Das, Nandini; Maiti, H. S.

2009-11-01

283

An accuracy evaluation of four removable die systems  

Microsoft Academic Search

Statement of problem. The advent of implant dentistry has redefined the need for accuracy of working cast models. Die stone expansion and errors introduced by removable die casts may exceed the accuracy required for the passive fit of implant prostheses. Purpose. Several removable die systems claim improved accuracy because of their design and\\/or technical advancements. This study evaluated the 3-dimensional

Juan Glen Serrano; Xavier Lepe; John D. Townsend; Glen H. Johnson; Stephen Thielke

1998-01-01

284

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

285

Application of quality criteria for the prediction of porosity in the design of casting processes.  

National Technical Information Service (NTIS)

Solidification parameters calculated from temperature measurements and experimentally determined distributions of porosity in gain- refined Al-4.5% Cu alloy castings are linked to provide quality criteria for the prediction of porosity in the computer-aid...

S. Viswanathan, V. K. Sikka, H. D. Brody

1993-01-01

286

Improvement of nuclear castings by application of hot isostatic pressing (HIP). Final report  

Microsoft Academic Search

A three-part team of foundries assess coal the benefits of hot-isostatic processing (HIP), a pressure heat treatment, as applied to cast stainless steel (CF-8 and CF-8M) valve components destined for nuclear power plant service. The basic goal was to establish the level of quality improvement obtained when pores, tears, and other flaws are eliminated from these castings. Improvement was expected

J. J. Mueller; M. Behravesh

1979-01-01

287

[Application of nitrides to dental casting. 2. Feasibility as coating materials for Co-Cr alloy].  

PubMed

Nitrides used in this experiment are hBN, A1N and Si3N4. We studied feasibility of nitrides as wax pattern coating materials for Co-Cr alloy in an atmosphere of argon. Wax patterns were painted with coating material of nitrides (first investing), then a mixture of phosphate bonded investment and water was used in outer investing (second investing). The temperature of mold was 800 degrees C, and an argon arc vacuum-pressure casting machine was used. We cast the thin specimens in Co-Cr alloy (composition Co: 63 wt%, Cr: 27 wt%, Mo: 5 wt%, Bal.: 5 wt%; melting point: 1,380 degrees C). Surfaces of cast specimens were investigated using the unaided eye, a scanning electron microscope and a surface roughness analyzer. Furthermore, the thick specimens (globular form: phi 6.5 mm) using coating material of hBN were investigated using the unaided eye. Results were summarized as follows; 1. The nitrides controlled remarkably the reaction between cast specimen and investment. 2. The nitrides had the good effect of separation. 3. The cast surface coated the nitrides had less clinging than uncoated one, and this indicated that its cleansability was improved. 4. The nitrides decreased the surface roughness (Rz) of the cast to about 1/3. 5. hBN had the best effect in nitrides. 6. hBN also had the effect in a thick globular specimen. PMID:2489703

Kanatani, M; Nomura, S; Ishioka, K; Hotta, N; Kimura, I

1989-02-01

288

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

289

Titanium investiment casting defects: A metallographic overview  

Microsoft Academic Search

Although titanium castings have been used in aerospace structures for decades, those uses have largely been in secondary applications. Expanding the use of titanium castings in critical applications would be encouraged by a better understanding of investment casting defects in titanium alloy systems. This paper describes several types of casting-related defects that are identified as potentially affecting the design life

J. D. Cotton; L. P. Clark; H. R. Phelps

2006-01-01

290

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 GradedSix common discontinuity types each illustrated in eight degrees of progressively increasing severity. 1.2.2 UngradedTwelve single illustrations of additional discontinuity types and of patterns and imper...

American Society for Testing and Materials. Philadelphia

2010-01-01

291

Recent advances in the application of modeling to the investment casting process  

SciTech Connect

Process modeling is being used to reduce development cycle time and cost, and improve the quality of investment castings. A critical component of modeling development is to improve model accuracy. Accuracy improvements are necessary not only for basic solutions such as fluid flow and thermal gradients, but they are also a prerequisite for more sophisticated analysis such as thermal stress and nonfill. This paper discusses accuracy improvements resulting from more complete and accurate thermophysical databases, improved estimates of the contact conductance between different materials, and more metallurgically correct methods to track latent heat evolution. Nonfill prediction techniques have been developed for the case of metal freeze off and applied to titanium castings. These results are being used to develop economical, high quality products and investment casting processes.

Foran, R.K.; Hansen, T.; Mueller, B. [Howmet Corp., Whitehall, MI (United States). Operhall Research Center

1995-12-31

292

Oxide films, pores and the fatigue lives of cast aluminum alloys  

NASA Astrophysics Data System (ADS)

In the absence of gross defects such as cold shuts, the fatigue properties of castings are largely determined by the sizes of microstructural defects, particularly pores and oxide films. In contrast, the effects of grain size, second-phase particles, and nonmetallic inclusions are insignificant. The authors review the fatigue properties of castings made by gravity die casting, sand casting, lost-foam casting, squeeze casting, and semisolid casting, and compare A356/357 alloys with 319-type alloys. The application of fracture mechanics enables the properties to be rationalized in terms of the defects that are characteristic of each casting process, noting both the sizes and types of defect. The differences in the properties of castings are entirely attributed to their different defect populations. No single process is inherently superior. For defects of the same size (in terms of projected area normal to the loading direction), oxide films are less detrimental to fatigue life than pores. Areas of current controversy are highlighted and suggestions for further work are made.

Wang, Q. G.; Crepeau, P. N.; Davidson, C. J.; Griffiths, J. R.

2006-12-01

293

Technological study of liquid die forging for the aluminum alloy connecting rod of an air compressor  

Microsoft Academic Search

The aluminum alloy connecting rod of an air compressor was manufactured with liquid die forging replacing die casting and hot die forging. Not only were the defects of gas holes, porosity and non-metal inclusions in the die casting eliminated, but also the investment of the forging equipment and the performing process were decreased, and the coefficient of material utilization and

F. Yin; G. X. Wang; S. Z. Hong; Z. P. Zeng

2003-01-01

294

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...

295

The application of defect maps in the process modeling of single-crystal investment casting  

Microsoft Academic Search

Defect maps, which plot the occurrences of defects on the bases of both temperature gradient and solidification rate, can be used as a performance criterion in process modeling for single-crystal components in order to reduce rejection rates and thereby lower costs. Attention is presently given to the case of defect mapping for single-crystal turbine blade investment castings subjected to grain

John S. Tu; R. K. Foran

1992-01-01

296

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...

297

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

Code of Federal Regulations, 2010 CFR

... Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS LOANS BY BANKS ON...Certificate Under the World War Adjusted Compensation Act...68th Cong.) 11.128 Veteran dies without having filed...

2010-07-01

298

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

Code of Federal Regulations, 2012 CFR

... Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS LOANS BY BANKS ON...Certificate Under the World War Adjusted Compensation Act...68th Cong.) 11.128 Veteran dies without having filed...

2012-07-01

299

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

Code of Federal Regulations, 2013 CFR

... Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS LOANS BY BANKS ON...Certificate Under the World War Adjusted Compensation Act...68th Cong.) 11.128 Veteran dies without having filed...

2013-07-01

300

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

Code of Federal Regulations, 2011 CFR

... Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS LOANS BY BANKS ON...Certificate Under the World War Adjusted Compensation Act...68th Cong.) 11.128 Veteran dies without having filed...

2011-07-01

301

Application of EDS microanalysis in the identification of inhomogeneities in surface protective layers on ductile cast iron parts  

NASA Astrophysics Data System (ADS)

In this study, the results of the application of both scanning electron microscopy and EDS microanalysis in investigations of the process of the protective layer formation on the surface of ductile cast iron (the substrate material) turbine blades are presented. The turbine blades, designated for operation in an aggressive environment, were coated with protective chromium carbide layers using plasma spraying methods. The first turbine blade was coated using a standard plasma spraying technique, followed by superficial remelting treatment, while the second one was coated using a modified plasma technology, i.e., HVOF (High Velocity Oxy Fuel) spraying technique.

Boro?, ?.; Tchrz, A.

2010-02-01

302

Influence of inclusion on nucleation of silicon casting for photovoltaic (PV) application  

NASA Astrophysics Data System (ADS)

The photovoltaic (PV) industry has grown rapidly in recent years. The predominant PV material, multicrystalline silicon (mc-Si), is manufactured by relatively low-cost casting methods, especially directional solidification. One factor affecting the quality of cast silicon and the resultant mc-Si solar cells is Si3N4 and SiC precipitates and inclusions. These inclusions cause crystal defects, distorted grain structure, decreased wafer yield and quality and even electrical shunts. A Computational Fluid Dynamic (CFD) Simulation tool has been applied to simulate temperatures and flow fields during growth and how they will affect the grain structure under the influence of inclusions. The Cellular Automata Finite Element (CAFE) modeling technique is used to simulate silicon grain growth.

Wu, Bei; Clark, Roger

2011-03-01

303

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, 290C (550F). The Argonne National Laboratory (ANL) recently completed a research program and the results indicate that the lower-bound fracture

O. Chopra

1997-01-01

304

Construction of highly nonlinear injective S-boxes with application to CAST-like encryption algorithms  

Microsoft Academic Search

We present two methods for constructing highly nonlinear injective S-boxes. Both of these methods, which are based on exponential sums, outperform previously proposed methods. In particular, we are able to obtain injective 832 S-boxes with nonlinearity equal to 80 and maximum XOR table entry of 2. We also reevaluate the resistance of the CAST like encryption algorithms constructed using randomly

A. M. Youssef; Z. G. Chen; S. E. Tavares

1997-01-01

305

Exploratory study on H13 steel dies  

SciTech Connect

Ultrahigh-strength H13 steel is a recommended die material for aluminum die casting; dies made from H13 steel can be safely water- cooled during hot working operations without cracking. However, after time the dies exhibited surface cracking and excessive wear. Erosive wear also occurs owing to high pressure injection of molten Al. An exploratory study was made of the causes for surface cracking of H13 dies. Results suggest that surface cracking is caused by interrelated factors, internal to the die material as well as externally induced conditions.

Sunwoo, A.J.

1994-04-01

306

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

307

Precision cast vs. wrought superalloys  

NASA Technical Reports Server (NTRS)

While cast polycrystalline superalloys recommend themselves in virtue of better 'buy-to-fly' ratios and higher strengthening gamma-prime volume fractions than those of wrought superalloys, the expansion of their use into such critical superalloy applications as gas turbine hot section components has been slowed by insufficient casting process opportunities for microstructural control. Attention is presently drawn, however, to casting process developments facilitating the production of defect-tolerant superalloy castings having improved fracture reliability. Integrally bladed turbine wheel and thin-walled turbine exhaust case near-net-shape castings have been produced by these means.

Tien, J. K.; Borofka, J. C.; Casey, M. E.

1986-01-01

308

Zinc Casting and Recycling (8 pp)  

Microsoft Academic Search

Aim, Scope and Background. Metal die casting is a highly energy-intensive industry. In addition to that, the production of primary zinc by smelting consumes huge amounts of energy as well as generates many types of pollution. This paper uses LCA to investigate the environmental performance of a zinc cast product. The areas of environmental concern are focused on the direct

Reginald Tan; Hsien H. Khoo

2005-01-01

309

Using EShP to obtain cast electroslag forging billets  

Microsoft Academic Search

The results of experimental industrial tests show convincingly that the use of cast electroslag die billets makes it possible to increase the strength of the die attachment, manufactured from the most modern high strength brands of steels 1.5 to 2 times, under operating conditions on highly productive presses and on the most recent automatic presses. Extensive introduction of cast electroslag

G. A. Boyko; V. S. Grinyuk; V. M. Shneyberg; N. A. Tsvetkov

1974-01-01

310

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

311

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

312

The application of defect maps in the process modeling of single-crystal investment casting  

NASA Astrophysics Data System (ADS)

Defect maps, which plot the occurrences of defects on the bases of both temperature gradient and solidification rate, can be used as a performance criterion in process modeling for single-crystal components in order to reduce rejection rates and thereby lower costs. Attention is presently given to the case of defect mapping for single-crystal turbine blade investment castings subjected to grain mapping and metallographic inspection. The solidification rate vs temperature gradient plot obtained can serve as a secondary performance criterion for process iteration.

Tu, John S.; Foran, R. K.

1992-06-01

313

Shrinkage Prediction for the Investment Casting of Stainless Steels  

Microsoft Academic Search

In this study, the alloy shrinkage factors were obtained for the investment casting of 17-4PH stainless steel parts. For the investment casting process, unfilled wax and fused silica with a zircon prime coat were used for patterns and shell molds, respectively. Dimensions of the die tooling, wax pattern, and casting were measured using a Coordinate Measurement Machine in order to

Sabau; Adrian S

2007-01-01

314

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

315

Classification techniques based on AI application to defect classification in cast aluminum  

NASA Astrophysics Data System (ADS)

This paper describes the Artificial Intelligent techniques applied to the interpretation process of images from cast aluminum surface presenting different defects. The whole process includes on-line defect detection, feature extraction and defect classification. These topics are discussed in depth through the paper. Data preprocessing process, as well as segmentation and feature extraction are described. At this point, algorithms employed along with used descriptors are shown. Syntactic filter has been developed to modelate the information and to generate the input vector to the classification system. Classification of defects is achieved by means of rule-based systems, fuzzy models and neural nets. Different classification subsystems perform together for the resolution of a pattern recognition problem (hybrid systems). Firstly, syntactic methods are used to obtain the filter that reduces the dimension of the input vector to the classification process. Rule-based classification is achieved associating a grammar to each defect type; the knowledge-base will be formed by the information derived from the syntactic filter along with the inferred rules. The fuzzy classification sub-system uses production rules with fuzzy antecedent and their consequents are ownership rates to every defect type. Different architectures of neural nets have been implemented with different results, as shown along the paper. In the higher classification level, the information given by the heterogeneous systems as well as the history of the process is supplied to an Expert System in order to drive the casting process.

Platero, Carlos; Fernandez, Carlos; Campoy, Pascual; Aracil, Rafael

1994-11-01

316

Impact properties of zinc die cast alloys  

SciTech Connect

Alloys 3, 5, AcuZinc 5, and ZA-8 were tested at five temperatures between -40 C and room temperature to determine impact properties. Izod impact energy data was obtained in accordance with ASTM D256. Unlike ASTM E23, these samples were tested with a milled notch in order to compare with plastic samples. In addition, flexural data was obtained for design use.

Schrems, Karol K.; Dogan, Omer N.; Manahan, M.P. (MPM Technologies, Inc.); Goodwin, F.E. (ILZRO)

2005-01-01

317

Industrial application of a numerical model to simulate lubrication, mould oscillation, solidification and defect formation during continuous casting  

NASA Astrophysics Data System (ADS)

In recent years, the addition of the slag phase to numerical models of the Continuous Casting (CC) process has opened the door to a whole new range of predictions. These include the estimation of slag infiltration and powder consumption (lubrication), heat transfer and cooling through the cooper mould (solidification) and investigating the effect of operational parameters such as mould oscillation and powder composition on surface quality / defect formation. This work presents 2D and 3D CC models capable of describing the dynamic behaviour of the liquid/solid slag in both the shell mould-gap and bed as well as its effects on heat extraction and shell formation. The present paper also illustrates the application of the model to a variety of casters and the challenges faced during its implementation. The model attained good agreement on the prediction of mould temperatures and shell thicknesses as well as slag film formation and heat flux variations during the casting sequence. The effect of different oscillation strategies (sinusoidal and non-sinusoidal) was explored in order to enhance powder consumption and surface quality. Furthermore, the modelling approach allows one to predict the conditions leading to irregular shell growth and uneven lubrication; these are responsible for defects such as, stickers, cracking and, in the worst case scenario, to breakouts. Possible mechanisms for defect formation are presented together with strategies to enhance process stability and productivity of the CC machine.

Ramirez Lopez, Pavel E.; Sjstrm, Ulf; Jonsson, Thomas; Lee, Peter D.; Mills, Kenneth C.; Petjjrvi, Marko; Pirinen, Jarno

2012-07-01

318

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

319

Worldline Casting of the Stochastic Vacuum Model and Non-Perturbative Properties of QCD: General Formalism and Applications  

E-print Network

The Stochastic Vacuum Model for QCD, proposed by Dosch and Simonov, is fused with a Worldline casting of the underlying theory, i.e. QCD. Important, non-perturbative features of the model are studied. In particular, contributions associated with the spin-field interaction are calculated and both the validity of the loop equations and of the Bianchi identity are explicitly demonstrated. As an application, a simulated meson-meson scattering problem is studied in the Regge kinematical regime. The process is modeled in terms of the "helicoidal" Wilson contour along the lines introduced by Janik and Peschanski in a related study based on a AdS/CFT-type approach. Working strictly in the framework of the Stochastic Vacuum Model and in a semiclassical approximation scheme the Regge behavior for the Scattering amplitude is demonstrated. Going beyond this approximation, the contribution resulting from boundary fluctuation of the Wilson loop contour is also estimated.

A. I. Karanikas; C. N. Ktorides

2008-10-07

320

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 10kg 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

321

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

322

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

323

Thermal and Kinetic Modelling of Elastomer FlowApplication to an Extrusion Die  

NASA Astrophysics Data System (ADS)

This paper reports and discusses the thermal and kinetic behaviour of elastomer flow inside an extrusion die. The reaction progress through the runner was modeled by using a particle tracking technique. The aim is to analyze viscous dissipation phenomena to control scorch arisen, improve the rubber compound curing homogeneity and reduce the heating time in the mould using the progress of the induction time. The heat and momentum equations were solved in three dimensions with Ansys Polyflow. A particle tracking technique was set up to calculate the reaction progress. Several simulations were performed to highlight the influence of process parameters and geometry modifications on the rubber compound thermal and cure homogeneity.

Launay, J.; Allanic, N.; Mousseau, P.; Deterre, R.

2011-05-01

324

Titanium investiment casting defects: A metallographic overview  

Microsoft Academic Search

Although titanium castings have been used in aerospace structures for decades, those uses have largely been in secondary applications.\\u000a Expanding the use of titanium castings in critical applications would be encouraged by a better understanding of investment\\u000a casting defects in titanium alloy systems. This paper describes several types of casting-related defects that are identified\\u000a as potentially affecting the design life

J. D. Cotton; L. P. Clark; H. R. Phelps

2006-01-01

325

SIMULATION OF POROSITY AND HOT TEARS IN A SQUEEZE CAST MAGNESIUM CONTROL ARM  

E-print Network

arms were produced as squeeze castings, using the steel die depicted in Fig. 2. Squeeze casting SIMULATION OF POROSITY AND HOT TEARS IN A SQUEEZE CAST MAGNESIUM CONTROL ARM K.D. Carlson1 , C: Magnesium Alloys, Casting, Shrinkage Porosity, Hot Tears, Modeling Abstract Simulations are performed

Beckermann, Christoph

326

RAPID THICK STRIP CASTING - CONTINUOUS CASTING WITH MOVING MOULDS  

Microsoft Academic Search

Moving mould for the future Due to mechanical reasons, conventional lubricated oscillating moulds limit the casting velocity. If the friction in the mould grows too strongly, the thin strand shell can tear, in a worst case followed by a breakout. However these constraints are not applicable to moving moulds. RTSC (Rapid Thick Strip Casting) is an innovative concept for the

R. Nagy; A. J. Hulek; D. Senk

327

Hair casts  

PubMed Central

Hair casts or pseudonits are circumferential concretions, which cover the hair shaft in such a way that, it could be easily removed. They are thin, cylindrical, and elongated in length. We present an unusual case of an 8-year-old girl presenting with hair casts. Occurrence of these is unusual, and they may have varied associations. This patient was suffering from developmental delay. It is commonly misdiagnosed as and very important to differentiate from pediculosis capitis.

Parmar, Sweta S.; Parmar, Kirti S.; Shah, Bela J.

2014-01-01

328

Hair casts.  

PubMed

Hair casts or pseudonits are circumferential concretions, which cover the hair shaft in such a way that, it could be easily removed. They are thin, cylindrical, and elongated in length. We present an unusual case of an 8-year-old girl presenting with hair casts. Occurrence of these is unusual, and they may have varied associations. This patient was suffering from developmental delay. It is commonly misdiagnosed as and very important to differentiate from pediculosis capitis. PMID:25396168

Parmar, Sweta S; Parmar, Kirti S; Shah, Bela J

2014-10-01

329

To cite this version : Niklas, Andrea and Abaunza, Unai and Fernandez-Calvo, Ana Isabel and Lacaze, Jacques. Relationship between casting modulus  

E-print Network

in the solidification conditions. For that purpose, thermal analysis cups and instrumented sand and die castings related to grain refinement in sand and die castings allowed determining the most significant parameters, Jacques. Relationship between casting modulus and grain size in cast A356 aluminium alloys. (2012). IOP

Paris-Sud XI, Université de

330

Rapid Tooling via Investment Casting and Rapid Prototype Patterns  

SciTech Connect

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

Baldwin, Michael D.

1999-06-01

331

a Study on the Failure Analysis of Cast Iron Brake Blocks that are Used for Railway Applications  

NASA Astrophysics Data System (ADS)

In order to clarify the cracking and failure behavior of gray cast iron brake blocks that are used for the railway applications, macro- and micro observations regarding the cracks and the micro-structure of the used brake blocks were examined. Three brake blocks, which have different degrees of hot spots and cracking during the actual application, were selected for testing. In addition, a thermal-mechanical coupled finite element analysis (FEA) was applied to calculate the temperature and the stress field in the brake blocks during braking. As a result, it was observed that surface cracks were initiated at the hot spots and propagated into the matrix. From the observation of dispersed graphites close to the crack path, it can be said that the deterioration of materials due to the frictional heat of braking made it easy to initiate cracks at the hot spot. The hardness of the brake block was recommended to be under 85 by the Rockwell B scale in order to prevent hot spots and crack initiation. From the FEA, the procedure for the occurrence of hot spots and cracks was successfully simulated by assuming the surface roughness on the slid surface of the brake block.

Suh, Chang-Min; Hwang, Byung-Won; Bae, Woo-Ho

332

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

333

Metal casting extended assessments  

SciTech Connect

In 1997, the Industrial Assessment Center program of the US Department of Energy initiated Extended Assessments as an option for some of their in-plant assessments. Intended for larger, more complex manufacturing facilities, the multi-day Extended Assessment allows the plant assessment team to explore more complex recommendations with the intent of encouraging major process and equipment changes. In this paper the authors describe the results of Extended Assessments at plants in the Metal Casting Industry, one of the DOE Industries of the Future. They visited five plants, two foundries and three die casting plants, with combined annual sales of $134 million and a combined annual production volume of 35,300 tons. The recommendations offered potential savings to each plant of an average $417,000 or 1.5% of average gross sales. A number of generalizations can be observed based on the assessments in the cast metals industry. First is that many of the smaller firms in this industry have been slow to adopt innovative technology. Off the shelf technologies are available that will help these firms reach the 21st Century. The concept of remelt of metal or scrap in the plant is an operation that can be improved. They found approximately two pounds of metal melted for every pound shipped. Finally, many opportunities exist outside of the core plant operations to reduce operating costs.

Ambs, L.; Kosanovic, D.; Muller, M.; Kasten, D.

1999-07-01

334

Dicing Die Attach Film for 3D Stacked Die QFN Packages  

Microsoft Academic Search

The application of die attach film (DAF) in semiconductor packaging is become wider especially in three dimensional (3D) QFN stacked die package. As wafer getting thinner until beyond 100 mum, challenges in die attach process become greater and die attach paste may not be suitable in most cases. DAF has many advantages including no die tilt, no void, consistent bond

S. Abdullah; S. Mohd Yusof; I. Ahmad; A. Jalar; R. Daud

2007-01-01

335

New fibreglass casting system in orthopaedic practice.  

PubMed

The composition, manufacture and application of a new fibreglass casting system for use in orthopaedic practice are described. The performance of the first 51 fibreglass casts used in routine fracture work is reviewed. The advantages (the cast is waterprof, extremely light and strong) and the disadvantages (an ultraviolet light source is required to cure the cast and the fiberglass tape is rather expensive) are evaluated. PMID:979766

Davis, B; Dooley, B

1976-06-26

336

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.

337

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

338

Die Verfassung  

Microsoft Academic Search

Laut seiner Verfassung ist das Groherzogtum ein demokratisches Staatswesen.2 Die Nation ist der Souvern. Der demokratische\\u000a Charakter ist eine relativ rezente Errungenschaft. Bis 1919 dominierten die autokratischen Merkmale, da zumindest gem der\\u000a Verfassung alle Attribute der Souvernitt in der Person des Groherzogs konzentriert waren. Erst 1919 wurde das Prinzip,\\u000a la puissance souveraine rside dans la Nation, in Artikel 32(1) der

Mario Hirsch; Marc Thewes

339

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

Federal Register 2010, 2011, 2012, 2013

...143] JL French Automotive Castings, LLC, Including On-Site...workers of JL French Automotive Castings LLC, including on-site leased...the production of aluminum die cast parts. The company reports...location of JL French Automotive Castings LLC. The Department has...

2010-11-12

340

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

341

Mechanical evaluation of a soft cast material.  

PubMed

In this study, the structural and material properties of a new semi-rigid material, Scotchcast SoftCast (SCS), were compared to the properties of two rigid materials, plaster of paris (POP) and Scotchcast Plus (SCP). Cylinders and flat beams made from 4, 6, 8, and 10 layers of each casting material were tested in three-point bending and diametrical compression. Initial stiffness and yield force values of SCS casts were significantly lower than for casts of SCP and POP made of the same number of layers. Casts made from SCS may be indicated for non-rigid applications, but not where rigid immobilization is required. PMID:9263288

Zmurko, M G; Belkoff, S M; Herzenberg, J E

1997-08-01

342

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 430C 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 250C to evaluate room- and high-temperature performance. Furthermore, the effect of aging at 300C 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

343

Simulating the deformation of dies in the foundry  

NASA Astrophysics Data System (ADS)

Digital simulation (QuikCAST, ProCAST) is already used extensively when designing metallic dies for founding, in particular to design filling and gating systems. Simulation of the steady-state temperature cycles of dies has also been mastered. With large castings, the temperature gradient induced between the moulding surface and the rear surfaces of the die leads to deformations that may be large enough to measure, and incompatible with the required dimensional accuracy. The temperature gradient also creates thermal fatigue stresses that cause crazing of the die surface. In the study conducted by CTIF, aimed at measuring tooling deformations, various ways of measuring displacements at high temperatures (with and without contact) were investigated in order to evaluate their capabilities and limitations. An experimental device was designed - a test bench combining a metallic die having a simple geometry, in which an aluminium part could be cast, and instrumentation (temperature and displacement sensors). The deformations of the die were measured during first cycles of temperature homogenization. Concurrently, thermomechanical calculations were carried out on the same geometry using PROCAST. The calculation results are well correlated with the experimental measurements and validate the tools and the calculation methods. This thermomechanical approach makes it possible to optimize die design in the foundry and to predict high-temperature deformations as early as the design stage. Knowledge of these deformations makes it possible in turn to anticipate the geometrical and dimensional variations undergone by the castings themselves and so to improve their accuracy. The designer can act on the temperature of the die or the design of the casting, or create a die in which the expected thermal deformation is reversed so as to produce a casting having the correct dimensions. In short, thermomechanical simulation can be applied to this problem to achieve a better understanding of the phenomena and to test solutions in advance.

Chabod, A.; Longa, Y.; Dracon, J. M.; Chailler, K.; Hairy, P.; Da Silva, A.

2012-07-01

344

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

345

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

346

SIMULATION OF STRESSES DURING CASTING OF BINARY MAGNESIUM-ALUMINUM ALLOYS M.G. Pokorny1  

E-print Network

heat treated or contained porosity (e.g., die cast specimens) must be excluded. Some studies have beenSIMULATION OF STRESSES DURING CASTING OF BINARY MAGNESIUM-ALUMINUM ALLOYS M.G. Pokorny1 , C, Geesthacht, Germany Keywords: Magnesium Alloys, Casting, Stress Simulation Abstract A visco

Beckermann, Christoph

347

Alloy Shrinkage Factors for the Investment Casting of 17-4PH Stainless Steel Parts  

Microsoft Academic Search

In this study, alloy shrinkage factors were obtained for the investment casting of 17-4PH stainless steel parts. For the investment casting process, unfilled wax and fused silica with a zircon prime coat were used for patterns and shell molds, respectively. The dimensions of the die tooling, wax pattern, and casting were measured using a coordinate measurement machine (CMM). For all

Adrian S. Sabau; Wallace D. Porter

2008-01-01

348

Influence of Bravo fungicide applications on wood density and moisture content of Swiss needle cast affected Douglas-fir trees  

Microsoft Academic Search

Wood density, moisture content, tracheid width and cell wall size were examined in trees from plots that were sprayed for 5 years with chlorothalonil (Bravo1) fungicide to reduce the impact of Swiss needle cast (SNC) and from trees in adjacent unsprayed plots. The unsprayed (more heavily diseased) trees had significantly narrower sapwood, narrower growth rings, lower sapwood moisture content, and

G. R. Johnson; Barbara L. Gartner; Alan Kanaskie

349

Industrial application of a numerical model to simulate lubrication, mould oscillation, solidification and defect formation during continuous casting  

Microsoft Academic Search

In recent years, the addition of the slag phase to numerical models of the Continuous Casting (CC) process has opened the door to a whole new range of predictions. These include the estimation of slag infiltration and powder consumption (lubrication), heat transfer and cooling through the cooper mould (solidification) and investigating the effect of operational parameters such as mould oscillation

Pavel E Ramirez Lopez; Ulf Sjstrm; Thomas Jonsson; Peter D Lee; Kenneth C Mills; Marko Petjjrvi; Jarno Pirinen

2012-01-01

350

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

E-print Network

(ingot mould filling, nozzle jet in continuous casting) and solid mechanics (stress-strain in solidified mechanics has been developed. Liquid flow (natural convection or filling flow), thermal dilatation as well Matériaux (CEMEF), UMR CNRS 7635, Sophia Antipolis, France Keywords: solidification, thermo-mechanical

Paris-Sud XI, Université de

351

Interaktives Ray-Tracing und Ray-Casting auf  

E-print Network

Interaktives Ray-Tracing und Ray-Casting auf programmierbaren Grafikkarten Bachelorarbeit. Januar 2005 Diese Version entstand durch die Bemerkungen und Hinweise, welche ich im Rahmen der Versicherung Hiermit erkl�re ich eidesstattlich, dass ich die vorliegende Arbeit selbst�ndig verfasst habe und

Toronto, University of

352

A comparison of the accuracy of three removable die systems and two die materials.  

PubMed

The purpose of this study was to evaluate the dimensional shift of three commonly used die systems (Conventional system, Pindex system, Di-Lok tray system) with two commercially available type IV die stones (Ultra rock and Pearl stone). Under controlled conditions, ten casts, each with two removable dies, were constructed for each system for a total of 30 casts and 60 removable dies. Before and after sectioning measurements to within 0.01 mm in horizontal and vertical planes were recorded and differences calculated. Data were analyzed with 't' tests, one way analysis of variance and post hoc Tukey test. The results demonstrated that among the die systems compared, no single system was superior to the others in all respects. But among the die materials, dies poured in Pearl stone exhibited more dimensional changes than Ultra rock (p<0.05). Selection of die material is as critical as selection of any particular die system for successful fabrication of fixed partial denture and implant prosthesis. PMID:24261103

Sivakumar, I; Mohan, J; Arunachalam, K S; Zankari, V

2013-09-01

353

Casting of electron field defining apertures: Casting with the metal mold kits  

SciTech Connect

Cerrobend alloy casts are made to define the desired electron field shapes. These custom casts are fabricated for the selected electron applicator size that has been chosen for the patient. When the cast is placed into that selected electron applicator, it will block out areas that are not to be treated. When an all metal mold assembly was used for the fabrication of these casts, the lip region of the cast which is used to accurately align the cast in the actual treatment applicator, had an irregular edge that prevented an accurate alignment of the cast. To eliminate the irregular edges on the lip region of the cast, the metal mold assembly was heated to approximately 80-85 degrees C before the molten cerrobend alloy was poured into it. The heating of the metal mold assembly helps eliminate the irregular edges on the lip region of the cast. Unfortunately it also created new flaws such as holes, dents, cracks and/or crystallization of the cast as it solidified. These flaws were controlled by cooling the metal mold assembly and the cast immediately after the pouring of the molten cerrobend alloy, evenly with water.

Dea, D.; San Luis, E. (Univ. of California, San Francisco (USA))

1988-09-01

354

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

355

LLNL casting technology  

Microsoft Academic Search

Competition to produce cast parts of higher quality, lower rejection rate, and lower cost is a fundamental factor in the global economy. To gain an edge on foreign competitors, the US casting industry must cut manufacturing costs and reduce the time from design to market. Casting research and development (R&D) are the key to increasing US competiveness in the casting

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

1994-01-01

356

Die Milchzhne des Feldhasen  

Microsoft Academic Search

ZusammenfassungDer gemeine Feldhase (Lepus europaeus Pallas 1778) ist ein heterodontes Sugetier, das zwei Zahngenerationen besitzt. Die Milchzahngeneration, die unterdrckt ist, verschwindet in der vierten Lebenswoche, whrend die Dauerzahngeneration, abgesehen von Unglcksfllen, bis zum Tode erhalten bleibt. Beim Feldhasen ist die Hypselodontie sekundr. Die Milchzhne, deren Zahl zwlf betrgt, haben Wurzeln, die den Dauerzhnen fehlen. Endlich besitzt dieses Sugetier ein einziges

D. Fraguglione

1957-01-01

357

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

358

The application of pattern recognition as defect prediction tool in solidification modeling of single crystal investment castings  

SciTech Connect

Solidification grain conditions were separated into four separate categories corresponding to the more common conditions found in single crystal production castings. The four grain conditions investigated were equiaxed grains, columnar grains, single crystals and freckle defects. Baseline computer models were developed which define these conditions in terms of various thermal history data obtained form the models, related to the thermal gradient (G) and rate of solidification (R) for the single crystal investment castings. By resolving the G and R values into vector components, as well as published criteria functions, numerous features of the thermal history were obtained and compared for the defining data. Extensive statistics were performed on the data to determine the statistical influence of each of the features on the categorization of the baseline data. The relative influence of the variables in identifying the grain conditions was determined by using pattern recognition, a categorization technique normally used in signal processing. It was discovered that many of the traditional features used in criteria functions were not influential when used to recognize the four grain condition categories of data. A least square 3 variable linear equation using the influential features was better for identification of grain conditions than more traditional methods in the categorization techniques. The baseline, or training data, was then tested with laboratory and production shaped solidification models to categorize the thermal history and compare directly with the defined baseline models. The numerical categorization was very consistent with experimental results and process changes were made to eliminate the undesirable grain conditions in several different casting shapes.

Purvis, A.L. [Bradley Univ., Peoria, IL (United States). Dept. of Industrial and Manufacturing Engineering and Technology; Hanslits, C.R. [Howmet Corp., Whitehall, MI (United States). Operhall Research Center

1995-12-31

359

Comparison of Mechanical Properties of TMW Alloys, New Generation of Cast-and-Wrought Superalloys for Disk Applications  

NASA Astrophysics Data System (ADS)

A new kind of Ni-Co-base disk alloys, named TMW alloys, has been developed on the basis of our innovative concept. Full-scale pancakes (440 mm in diameter and 65 mm in thickness) with an average grain size of about 10 ?m were successfully manufactured from TMW alloys by a conventional cast-and-wrought (C&W) processing route. The property assessments of the pancakes indicate that TMW alloys are superior to C&W U720Li alloys in tensile strength and in creep resistance, while the performances of low-cycle fatigue (LCF) and fatigue crack growth (FCG) are comparative.

Gu, Y. F.; Fukuda, T.; Cui, C.; Harada, H.; Mitsuhashi, A.; Yokokawa, T.; Fujioka, J.; Koizumi, Y.; Kobayashi, T.

2009-12-01

360

Relationship between casting modulus and grain size in cast A356 aluminium alloys  

NASA Astrophysics Data System (ADS)

Microstructure of Al-Si alloy castings depends most generally on melt preparation and on the cooling rate imposed by the thermal modulus of the component. In the case of Al-Si alloys, emphasis is put during melt preparation on refinement of pro-eutectic (Al) grains and on modification of the Al-Si eutectic. Thermal analysis has been used since long to check melt preparation before casting, i.e. by analysis of the cooling curve during solidification of a sample cast in an instrumented cup. The conclusions drawn from such analysis are however valid for the particular cooling conditions of the cups. It thus appeared of interest to investigate how these conclusions could extrapolate to predict microstructure in complicated cast parts showing local changes in the solidification conditions. For that purpose, thermal analysis cups and instrumented sand and die castings with different thermal moduli and thus cooling rates have been made, and the whole set of cooling curves thus recorded has been analysed. A statistical analysis of the characteristic features of the cooling curves related to grain refinement in sand and die castings allowed determining the most significant parameters and expressing the cube of grain size as a polynomial of these parameters. After introduction of a further parameter quantifying melt refining an excellent correlation, with a R2 factor of 0.99 was obtained.

Niklas, A.; Abaunza, U.; Fernndez-Calvo, A. I.; Lacaze, J.

2012-01-01

361

A finite element method for casting simulations  

SciTech Connect

The rapid growth in the use of advanced materials in a large number of highly demanding automotive, electronic, and consumer applications has promoted the development of new and more complex material forming processes. A good understanding of the interaction between material and processing conditions is now very important in order to comply with stricter tolerances and demanding service conditions. This is particularly important in the case of castings involving the filling of a die where the coupled phenomena of fluid flow and heat transfer determine, to a large extent the final properties of the part. This paper presents a finite element model for the three-dimensional simulation of industrial mold filling and solidification problems. The finite element solutions of mold filling problems involve highly convective fluid flow coupled with free surface, heat transfer, nonconstant material properties, and complex three-dimensional geometries. They present unusual challenges for both the finite element modeling and numerical solution algorithms. In this work a segregated algorithm is proposed to solve Navier-Stokes, energy, and front tracking equations. The streamline upwind Petrov-Galerkin formulation is used to obtain stable solutions. The position of the free surface is modeled using a level-set approach. The whole procedure is shown to present the accuracy, robustness, and cost-effectiveness needed for complex three-dimensional industrial applications.

Hetu, J.F.; Ilinca, F.

1999-11-26

362

Microstructure and tensile properties of squeeze cast magnesium alloy AM50  

NASA Astrophysics Data System (ADS)

High-pressure die cast magnesium alloy AM50 is currently used extensively in large and complex shaped thin-wall automotive components. For further expansion of the alloy usage in automobiles, novelmanufacturing processes need to be developed. In this study, squeeze casting of AM50 alloy with a relatively thick cross section was carried out using a hydraulic press with an applied pressure of 70 MPa. Microstructure and mechanical properties of the squeeze cast AM50 with a cross-section thickness of 10 mm were characterized in comparison with the die cast counterpart. The squeeze cast AM50 alloy exhibits virtually no porosity in the microstructure as evaluated by both optical microscopy and the density measurement technique. The results of tensile testing indicate the improved tensile properties, specifically ultimate tensile strength and elongation, for the squeeze cast samples over the conventional high-pressure die cast parts. The analysis of tensile behavior show that the strain-hardening rate during the plastic deformation of the squeeze cast specimens is constantly higher than that of the die cast specimens. The scanning electron microscopy fractography evidently reveals the ductile fracture features of the squeeze cast alloy AM50.

Zhou, Ming; Hu, Henry; Li, Naiyi; Lo, Jason

2005-08-01

363

Improving Tribological Properties of Cast Al-Si Alloys through Application of Wear-Resistant Thermal Spray Coatings  

NASA Astrophysics Data System (ADS)

Flame Spray Thermal Spray coatings are low-cost, high-wear surface-treatment technologies. However, little has been reported on their potential effects on cast automotive aluminum alloys. The aim of this research was to investigate the tribological properties of as-sprayed NiCrBSi and WC/12Co Flame Spray coatings applied to two cast aluminum alloys: high-copper LM24 (AlSi8Cu3Fe), and low-copper LM25 (AlSi7Mg). Potential interactions between the mechanical properties of the substrate and the deposited coatings were deemed to be significant. Microstructural, microhardness, friction, and wear (pin-on-disk, microabrasion, Taber abrasion, etc.) results are reported, and the performance differences between coatings on the different substrates were noted. The coefficient of friction was reduced from 0.69-0.72 to 0.12-0.35. Wear (pin-on-disk) was reduced by a factor of 103-104, which was related to the high surface roughness of the coatings. Microabrasion wear was dependent on coating hardness and applied load. Taber abrasion results showed a strong dependency on the substrate, coating morphology, and homogeneity.

Culliton, David; Betts, Anthony; Carvalho, Sandra; Kennedy, David

2013-04-01

364

The production of large structural titanium castings  

NASA Astrophysics Data System (ADS)

Titanium-alloy castings have recently become an attractive option for critical-structural applications in aerospace structures. These opportunities have occurred primarily because of the development of advanced-process technologies, such as rapid-prototyping methodology and solidification modeling, which have dramatically reduced the cost and time required to obtain first-article castings through concurrent engineering. Moreover, these technologies have lowered the risk involved in examining new applications for titanium castings. This article examines the implementation of these new technologies and the heat treatment and mechanical properties of large structural castings, particularly in relation to section size. Additionally, the production of a cast-titanium transmission adapter for the V-22 Osprey Tiltrotoraircraft is described.

Klepeisz, J.; Veeck, S.

1997-11-01

365

Sensor-Based Assessment of Cast Placement and Removal  

PubMed Central

Appropriate pressure during the application of a cast is critical to provide adequate stabilization of fractures. Force-sensing resistors (FSR) were used to measure pressure during cast placement and removal. The data demonstrated a signature pattern of skin pressure during the different steps of cast placement and removal. This reproducible signal provides validity evidence for our model. PMID:24732518

MAAG, Anne-Lise D.; LAUFER, Shlomi; KWAN, Calvin; COHEN, Elaine R.; LENHART, Rachel L.; STORK, Natalie C.; HALANSKI, Matthew A.; PUGH, Carla M.

2014-01-01

366

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

367

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

368

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

369

Modified soft tissue cast for fixed partial denture: a technique  

PubMed Central

In process of fabrication of a fixed partial denture, dies are trimmed to expose margins of the preparations. The need for the soft tissue cast is quite evident as the soft tissue emergence profile that surrounds the prepared tooth is destroyed in the process of fabrication. This article describes a modified technique to fabricate the soft tissue cast for the conventional fixed partial denture. The impression made with the polyvinylsiloxane was first poured to prepare the die cast. After retrieval of the cast, the same impression was poured second time with the resin based resilient material to cover the facial and proximal gingival areas. The remaining portion of the impression was poured with the gypsum material. This technique does not require additional clinical appointment, second impression procedure, technique sensitive manipulations with impression, or cumbersome laboratory procedures. The simplicity of this technique facilitates and justifies its routine use in fabrication of the fixed partial denture. PMID:21503191

2011-01-01

370

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

371

LLNL casting technology  

NASA Astrophysics Data System (ADS)

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

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

1994-01-01

372

LLNL casting technology  

SciTech Connect

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

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

1994-01-01

373

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

374

Investigation on Tool Wear Rate for Modified and Unmodified Aluminium-Silicon Casting Alloy  

NASA Astrophysics Data System (ADS)

This study demonstrates and explains the effect of strontium modification on machinability of aluminium-silicon eutectic (LM-6 type) alloy. This alloy is known to have many favourable features including weight to strength ratio, high corrosion resistance and excellent castability. However, normal unmodified LM-6 alloy has poor machinability, which reduces its applications range. In this work, various samples of LM-6 alloy were cast using sand and metallic chill mould with and without strontium addition. Machining on each cast product, was carried out using recommended cutting parameters for Al-Si alloys. Strontium modified samples have recorded a reduction in average flank wear, an increase in shear plane angles and a reduction in chip thickness. The main reason for this improvement is the refining effect of strontium, which reduces the size of the hard silicon particles. As a result, their abrasive action on the tool face has reduced a lot. Dramatic reductions in tool wear rate were recorded when the microstructures were refined. On the other hand, when no refinement of microstructure occurs, tool wear rate becomes high. Chip analysis showed that strontium modified sample produced a thinner chip thickness with a larger shear plane angle, requiring less cutting forces. The tool wear depends not only on the phases present in the work material, but also on their sizes and distribution over entire structure. Thus, strontium modification has better effect on machinability of die cast alloy compared to that of the sand cast LM-6 alloy.

Haque, M. M.; Khan, A. A.; Ismail, Ahmad F.

375

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 ...

Issen, Ms.

2009-09-17

376

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.

Blind, Perkins S.

2012-06-26

377

Evaluation of electroslag castings  

SciTech Connect

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

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

1985-01-01

378

Faster, Less Expensive Dies Using RSP Tooling  

NASA Astrophysics Data System (ADS)

RSP Tooling is an indirect spray form additive process that can produce production tooling for virtually any forming process and from virtually any metal. In the past 24 months a significant amount of research and development has been performed. This resulted in an increase in the basic metallurgical understanding of what transpires during the rapid solidification of the metal, significant improvements in the production machine up time, ceramic developments that have improved finish, process changes that have resulted in a shorter lead time for tool delivery, and the testing of many new alloys. RSP stands for Rapid Solidification Process and is the key to the superior metallurgical properties that result from the technology. Most metals that are sprayed in the process leave the machine with the same physical properties as the same metal normally achieves through heat treatment and in some cases the properties are superior. Many new applications are being pursued including INVAR tools for aerospace composite materials, and bimetallic tools made from tool steel and beryllium copper for die casting and plastic injection molding. Recent feasibility studies have been performed with tremendous success.

Knirsch, James R.

2007-08-01

379

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

380

Beryllium-aluminum alloys for investment castings  

SciTech Connect

Beryllium-aluminum alloys containing greater than 60 wt % beryllium are very favorable materials for applications requiring light weight and high stiffness. However, when produced by traditional powder metallurgical methods, these alloys are expensive and have limited applications. To reduce the cost of making beryllium-aluminum components, Nuclear Metals Inc. (NMI) and Lockheed Martin Electronics and Missiles have recently developed a family of patented beryllium-aluminum alloys that can be investment cast. Designated Beralcast, the alloys can achieve substantial weight savings because of their high specific strength and stiffness. In some cases, weight has been reduced by up to 50% over aluminum investment casting. Beralcast is now being used to make thin wall precision investment castings for several advanced aerospace applications, such as the RAH-66 Comanche helicopter and F-22 jet fighter. This article discusses alloy compositions, properties, casting method, and the effects of cobalt additions on strength.

Nachtrab, W.T.; Levoy, N. [Nuclear Metals Inc., Concord, MA (United States)

1997-05-01

381

Shrinkage Prediction for the Investment Casting of Stainless Steels  

SciTech Connect

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

Sabau, Adrian S [ORNL

2007-01-01

382

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

NASA Astrophysics Data System (ADS)

The development of alternative manufacturing processes is essential for the success in applying Ca-containing magnesium alloys for automotive applications due to their relatively poor die castability. Squeeze casting with its inherent advantages has been demonstrated capable of minimizing the formation of casting defects in Mg-Al-Ca alloys. In this study, the effect of applied pressures on tensile behavior and microstructure of squeeze cast Mg-5wt.%Al-1%wt.%Ca alloy (AMX501) was investigated with the applied pressure varying from 3 to 90 MPa. The results of tensile testing indicate that the tensile properties of AMX501 alloy including ultimate tensile strength, yield strength, and elongation ( E f) increase from 153.7, 80 MPa and 3.26% to 183.7, 90.5, and 5.42% with increasing applied pressure levels from 3 to 90 MPa, respectively. The analysis of true stress versus strain curves shows that an increase in applied pressure levels result in high straining hardening rates during the plastic deformation of the alloy. Microstructural analysis and density measurements indicate that, as the applied pressure increases, the porosity levels of the alloy decrease considerably, despite of almost no significant reduction in grain sizes of the squeeze cast alloys due to their high aspect ratio of cylindrical castings. Hence, the improvement in tensile properties should be primarily attributed to casting densification resulting from applied pressures. The scanning electron microscopy observation on fractured surfaces reveals that the fracture modes of the squeeze cast alloys transit to ductile from brittle with increasing applied pressures.

Zhang, Qiang; Masoumi, Mohsen; Hu, Henry

2012-01-01

383

Prediction of ALLOY SHRINKAGE FACTORS FOR THE INVESTMENT CASTING PROCESS  

SciTech Connect

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

Sabau, Adrian S [ORNL

2006-01-01

384

Casting accuracy of experimental Ti-Cu alloys.  

PubMed

The purpose of the present study was to investigate the casting accuracy and the dimensional change of experimental titanium-copper alloys (3.0 and 5.0 mass% Cu; hereafter, only "%" will be used) and to compare the findings with those of pure titanium. Castings were made using an argon-arc melting/pressure difference-casting unit. The fit of the metals cast in both full crown and MOD inlay dies was evaluated by measuring the distance between the shoulder margin and the cervical shoulder of the die. The changes in the inner diameter of castings were determined. In addition, surface roughness measurements inside the castings were carried out using a conventional profilometer, and thermal expansion measurements were made on cast cylindrical specimens using a differential dilatometer. There were no significant differences in dimensional change between pure titanium and the titanium-copper alloys. The fit of the titanium-copper alloys was inferior to pure titanium. The results of surface roughness measurements showed significance differences between the roughness of the pure titanium and titanium-copper alloys. PMID:11441485

Hattori, M; Hasegawa, K; Yoshinari, M; Kawada, E; Oda, Y; Okabe, T

2001-03-01

385

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...

386

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...

387

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

388

1. Introduction Flow in the mold region during the continuous casting of  

E-print Network

1. Introduction Flow in the mold region during the continuous casting of steel is of great interest­1271 © 2001 ISIJ 1262 Comparison of Four Methods to Evaluate Fluid Velocities in a Continuous Slab Casting. Transient computations are then performed using a 1.5-million node grid to resolve the turbulent ed- dies

Thomas, Brian G.

389

A simple technique for exposing margins on a solid working cast.  

PubMed

Removable dies used in fixed prosthodontics typically exhibit movement. A solid working cast permits the technician to perfect the interproximal contacts of fixed prostheses. This saves the clinician time at the insertion appointment. This article describes a quick and easy procedure for making a solid working cast with easily visualized margins. PMID:9710830

Windhorn, R J

1998-08-01

390

Alloy Shrinkage Factors for the Investment Casting of 17-4PH Stainless Steel Parts  

Microsoft Academic Search

In this study, alloy shrinkage factors were obtained for the investment casting of 17-4PH stainless steel parts. For the investment\\u000a casting process, unfilled wax and fused silica with a zircon prime coat were used for patterns and shell molds, respectively.\\u000a The dimensions of the die tooling, wax pattern, and casting were measured using a coordinate measurement machine (CMM). For\\u000a all

Adrian S. Sabau; Wallace D. Porter

2008-01-01

391

Internal adaptation of cast titanium crowns.  

PubMed

As the adaptation of titanium crowns obtained by Rematitan Plus investment, specific for titanium, is not recognized to be suitable, this study evaluated the effect of the concentration of the specific liquid and the temperature of the mold of investments on the internal misfit of crowns cast on commercially pure titanium. Individual dies of epoxy resin were obtained, representing teeth prepared for full-crown restoration with a 6-degree axial surface convergence angle and shoulder (1.0 mm). For the waxing of each crown, a ring-shaped stainless steel matrix (8.0mm internal diameter; 7.5 mm height) was adapted above the individual dies of epoxy resin. The Rematian Plus investment was mixed according to the manufacturer's instructions using two different concentrations of the specific liquid: 100%, 75%. Casting was performed in a Discovery Plasma Ar-arc vacuum-pressure casting machine with molds at temperatures of 430 degrees C, 515 degrees C and 600 degrees C. The crowns were cleaned individually in a solution (1% HF + 13% HNO3) for 10 min using a ultrasonic cleaner, with no internal adaptations, and luted with zinc phosphate cement under a 5 kg static load. The crown and die assemblies were embedded in resin and sectioned longitudinally. The area occupied by cement was observed using stereoscopic lens (10X) and measured by the Leica Qwin image analysis system (mm(2)). The data for each experimental condition (n=8) were analyzed by Kruskal-Wallis non-parametric test (=0.05). The results showed that liquid dilution and the increase in mold temperature did not significantly influence the levels of internal fit of the cast titanium crowns. The lowest means (+/-SD) of internal misfit were obtained for the 430 degrees C/100%: (7.25 mm(2) +/-1.59) and 600 degrees C/100% (8.8 mm(2) +/-2.25) groups, which presented statistically similar levels of internal misfit. PMID:19089139

da Rocha, Sicknan Soares; Adabo, Gelson Luis; Ribeiro, Ricardo Faria; Fonseca, Renata Garcia

2007-08-01

392

Improving Metal Casting Process  

NASA Technical Reports Server (NTRS)

Don Sirois, an Auburn University research associate, and Bruce Strom, a mechanical engineering Co-Op Student, are evaluating the dimensional characteristics of an aluminum automobile engine casting. More accurate metal casting processes may reduce the weight of some cast metal products used in automobiles, such as engines. Research in low gravity has taken an important first step toward making metal products used in homes, automobiles, and aircraft less expensive, safer, and more durable. Auburn University and industry are partnering with NASA to develop one of the first accurate computer model predictions of molten metals and molding materials used in a manufacturing process called casting. Ford Motor Company's casting plant in Cleveland, Ohio is using NASA-sponsored computer modeling information to improve the casting process of automobile and light-truck engine blocks.

1998-01-01

393

Cast aluminized explosives (review)  

Microsoft Academic Search

This paper reviews the current status and future trends of aluminized explosives. The major focus is on cast compositions,\\u000a which encompass both the melt-cast trinitrotoluene (TNT) based and the slurry cast polymer-based compositions. Widely reported\\u000a RDX and HMX based aluminized compositions with TNT used as a binder are discussed in detail. Various researchers have suggested\\u000a a 1520% Al content as

P. P. Vadhe; R. B. Pawar; R. K. Sinha; S. N. Asthana; A. Subhananda Rao

2008-01-01

394

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

395

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

396

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

397

Hickey, W8206, all casts Hickey, W8206, all casts, page 1  

E-print Network

Hickey, W8206, all casts Hickey, W8206, all casts, page 1 #12;Hickey, W8206, all casts Hickey, W8206, all casts, page 2 #12;Hickey, W8206, all casts Hickey, W8206, all casts, page 3 #12;Hickey, W8206, all casts Hickey, W8206, all casts, page 4 #12;Hickey, W8206, all casts Hickey, W8206, all casts, page

Hickey, Barbara

398

Die Wirkung von Bradykinin auf die zerebrale Mikrozirkulation.  

E-print Network

??In der vorliegenden Arbeit wurde die Wirkung von Bradykinin auf die zerebrale Mikrozirkulation untersucht. Von besonderer Bedeutung war hierbei die Beurteilung der Interaktion von Leukozyten (more)

Waldner, Maximilian

2007-01-01

399

Thermal fatigue of materials for die-casting tooling  

Microsoft Academic Search

This research is conducted to study the thermal fatigue resistance of different hot-work tool steels; AISI H11 and H13, special tool steel and 18% Ni maraging steel. The maraging steel is surface cladded by GTA welding to study the thermal fatigue resistance of surface layer. An influence of mechanical and microstructural properties on thermal fatigue resistance is evaluated. An innovative

D. Klob?ar; J. Tuek; B. Taljat

2008-01-01

400

Cyclic material behaviour of magnesium die castings and extrusions  

Microsoft Academic Search

An increasing number of components are designed by using the local strain concept. This concept is commonly used for many different materials. The question is, can the local concept be used for components made of magnesium alloys? Therefore the material behaviour must be described and the material properties need to be adequate.The main topic of the present investigations is the

H Zenner; F Renner

2002-01-01

401

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

402

Racing Game with One Die  

NSDL National Science Digital Library

In this activity, students roll a die that will advance either a blue or red car in a race to the finish. Students can adjust which numbers on the die make each car move, changing the probability that each car will win. This activity allows students to explore experimental and theoretical probability by running multiple races at once and examining how often each car wins and comparing that to how often each car is expected to win. This activity includes supplemental materials, including background information about the topics covered, a description of how to use the application, and exploration questions for use with the java applet.

2010-01-01

403

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

404

Die aszendierende Varikophlebitis  

Microsoft Academic Search

Zusammenfassung Die Varikophlebitis ist die wichtigste akute Komplikation einer Stammvarikosis vom V.-saphena-magna- und\\/oder -parva-Typ.\\u000a Durch Aszension kann es zu einer Migration des Thrombus in das tiefe Venensystem ber die Mndungen der Stammvenen in Leiste\\u000a und Kniekehle oder ber insuffiziente Vv. perforantes kommen, wodurch die Komplikation einer Lungenembolie droht. Ausdehnung\\u000a und Progression einer aszendierenden Varikophlebitis lassen sich mit der Duplexsonographie und\\/oder

F. Verrel; B. Steckmeier; A. Parzhuber; F. A. Spengel; G. Rauh; C. B. Reininger

1999-01-01

405

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. Mageblich durch das Eingreifen Albert Einsteins entwickelte sich daraus im folgenden Vierteljahrhundert eine fundamentale Krise der Physik, die dann in einer wissenschaftlichen Revolution groten Ausmaes mundete: der Quantentheorie. Die Quantentheorie entwickelte sich von Anfang an diametral gegen

Domenico Giulini

406

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

407

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

408

New Zinc alloys for semisolid applications  

Microsoft Academic Search

A new alloy for fashion products, alternative to traditional die-cast Zamak and hot-forged brass, was designed. The attention\\u000a was focused on zinc-based alloy and different chemical compositions were investigated, mainly containing aluminum and copper\\u000a as alloying elements, in order to obtain a proper material also for semisolid applications. The semisolid microstructure was\\u000a obtained by ultrasound treatment of the liquid metal.

A. Pola; R. Roberti; L. Montesano

2010-01-01

409

Effect of serial casting in spastic cerebral palsy  

Microsoft Academic Search

ObjectiveCerebral palsy (CP) is a range of non progressive syndromes of posture and motor impairment due to an insult to developing\\u000a brain. Spasticity and incoordination are major causes of disability in these children which can be managed by different modalities\\u000a like casting, botulinum toxin, surgery etc. Cast application in spastic equinus is a well established procedure in CP but\\u000a cast

Shweta Jain; Navnendra Mathur; Mrinal Joshi; Rajeshwari Jindal; Sunil Goenka

2008-01-01

410

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

411

Casting in Sport  

PubMed Central

Attempts by sports medicine professionals to return high school athletes with hand and wrist injuries to competition quickly and safely have been the source of confusion and debate on many playing fields around the country. In addition to the differing views regarding the appropriateness of playing cast usage in high school football, a debate exists among sports medicine professionals as to which material is best suited for playing cast construction. Materials used in playing cast construction should be hard enough to provide sufficient stabilization to the injured area and include adequate padding to absorb blunt impact forces. The purpose of the biomechanical portion of this investigation was to attempt to determine the most appropriate materials for use in constructing playing casts for the hand and wrist by assessing different materials for: 1) hardness using a Shore durometer, and 2) ability to absorb impact using a force platform. Results revealed that RTV11 and Scotchcast were the least hard of the underlying casting materials and that Temper Stick foam greatly increased the ability of RTV11 to absorb impact. Assessment of the mechanical properties of playing cast materials and review of current developments in high school football rules are used to aid practitioners in choosing the most appropriate materials for playing cast construction. ImagesFig 1.Fig 2.Fig 3. PMID:16558257

DeCarlo, Mark; Malone, Kathy; Darmelio, John; Rettig, Arthur

1994-01-01

412

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

413

78 FR 15048 - Johnstown Specialty Castings, Inc., a Subsidiary of WHEMCO, Johnstown, Pennsylvania; Notice of...  

Federal Register 2010, 2011, 2012, 2013

...TAA) applicable to workers and former workers of Johnstown Specialty Castings, Inc., a subsidiary of...related to the production of steel castings, slag pots, steel rolls, steel sleeves, and mill liners. The...

2013-03-08

414

75 FR 71456 - Algonac Cast Products, Inc., Algonac, MI; Notice of Affirmative Determination Regarding...  

Federal Register 2010, 2011, 2012, 2013

...Employment and Training Administration [TA-W-74,549] Algonac Cast Products, Inc., Algonac, MI; Notice of Affirmative Determination...Assistance (TAA) applicable to workers and former workers of Algonac Cast Products, Inc., Algonac, Michigan (subject firm)....

2010-11-23

415

Impact of Simulation Technology on Die and Stamping Business  

NASA Astrophysics Data System (ADS)

Over the last ten years, we have seen an explosion in the use of simulation-based techniques to improve the engineering, construction, and operation of GM production tools. The impact has been as profound as the overall switch to CAD/CAM from the old manual design and construction methods. The changeover to N/C machining from duplicating milling machines brought advances in accuracy and speed to our construction activity. It also brought significant reductions in fitting sculptured surfaces. Changing over to CAD design brought similar advances in accuracy, and today's use of solid modeling has enhanced that accuracy gain while finally leading to the reduction in lead time and cost through the development of parametric techniques. Elimination of paper drawings for die design, along with the process of blueprinting and distribution, provided the savings required to install high capacity computer servers, high-speed data transmission lines and integrated networks. These historic changes in the application of CAE technology in manufacturing engineering paved the way for the implementation of simulation to all aspects of our business. The benefits are being realized now, and the future holds even greater promise as the simulation techniques mature and expand. Every new line of dies is verified prior to casting for interference free operation. Sheet metal forming simulation validates the material flow, eliminating the high costs of physical experimentation dependent on trial and error methods of the past. Integrated forming simulation and die structural analysis and optimization has led to a reduction in die size and weight on the order of 30% or more. The latest techniques in factory simulation enable analysis of automated press lines, including all stamping operations with corresponding automation. This leads to manufacturing lines capable of running at higher levels of throughput, with actual results providing the capability of two or more additional strokes per minute. As we spread these simulation techniques to the balance of our business, from blank de-stacking to the racking of parts, we anticipate continued reduction in lead-time and engineering expense while improving quality and start-up execution. The author will provide an overview of technology and business evolution of the math-based process that brought an historical transition and revitalization to the die and stamping industry in the past decade. Finally, the author will give an outlook for future business needs and technology development directions.

Stevens, Mark W.

2005-08-01

416

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 (760C, 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 800C. 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

417

Numerical Optimization of the Method of Cooling of a Massive Casting of Ductile Cast-Iron  

NASA Astrophysics Data System (ADS)

The numerical models of the temperature field of solidifying castings, according to various authors, have been observing two main goalsdirected solidification as the basic assumption for the healthiness of a casting and the optimization of the technology while maintaining the optimal product properties. The achievement of these goals is conditioned by the ability to analyze and, successively, to control the effect of the deciding factors, which either characterize the process or accompany it. An original application of ANSYS simulated the forming of the temperature field of a massive casting from ductile cast-iron during the application various methods of its cooling using steel chills. The numerical model managed to optimize more than one method of cooling but, in addition to that, provided serious results for the successive model of structural and chemical heterogeneity, and so it also contributes to influencing the pouring structure. The file containing the acquired results from both models, as well as from their organic unification, brings new and, simultaneously, remarkable findings of causal relationships between the structural and chemical heterogeneity (i.e. between the sizes of the spheroids of graphite, the cells, density of the spheroids of graphite, etc.) and the local solidification time in any point of the casting. The determined relations therefore enable the prediction of the face density of the spheroids of graphite in dependence on the local solidification time. The calculated temperature field of a two-ton 5005001000 mm casting of ductile cast-iron with various methods of cooling has successfully been compared with temperatures obtained experimentally. The casting was cast in sand mould. The calculated model of the kinetics of the temperature field of the casting was verified during casting with temperature measurements in selected points. This has created a tool for the optimization of the structure with an even distribution of the spheroids of graphite in such a way so as to minimize the occurrence of degenerated shapes of graphite, which happens to be one of the conditions for achieving good mechanical properties of castings of ductile cast-iron.

Dobrovska, Jana; Kavicka, Frantisek; Stransky, Karel; Sekanina, Bohumil; Stetina, Josef

2010-06-01

418

Effect of pre\\/post T6 heat treatment on the mechanical properties of laser welded SSM cast A356 aluminium alloy  

Microsoft Academic Search

Aluminium alloy A356 was treated by the Rheo semi solid metal (SSM) process, developed recently by CSIR-Pretoria, and cast in plates using a high pressure die casting (HPDC) machine. Plates in as cast condition (F) and heat treated T6 condition (pre HT) were butt welded, using an Nd:YAG laser. In another experiment, as cast welded samples were heat treated to

R. Akhter; L. Ivanchev; H. P. Burger

2007-01-01

419

New approaches in microcasting: permanent mold casting and composite casting  

Microsoft Academic Search

For several years, microcasting was based on investment casting. New approaches are now the permanent mold casting and composite\\u000a casting of micro parts. Casting was performed with aluminum bronze of the type CuAl10Ni5Fe4. Permanent mold casting was commenced with steel mold inserts in a lost mold. The development of a band heater enabled the\\u000a heating of permanent molds inside the

G. Baumeister; D. Buqezi-Ahmeti; J. Glaser; H.-J. Ritzhaupt-Kleissl

2011-01-01

420

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

421

Translating Water Spray Cooling of a Steel Bar Sand Casting Thomas J. Williams, Daniel Galles, and Christoph Beckermann  

E-print Network

Translating Water Spray Cooling of a Steel Bar Sand Casting Thomas J. Williams, Daniel Galles. The present study investigates the potential application of the ablation casting method to steel castings promise for use in steel casting, several issues remain, such as finding a suitable water-soluble binder

Beckermann, Christoph

422

A Winning Cast  

NASA Technical Reports Server (NTRS)

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

2001-01-01

423

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

Zilinskas, Juozas; Junevicius, Jonas; Ramonaite, Agne; Pavilonis, Alvydas; Gleiznys, Alvydas; Sakalauskiene, Jurgina

2014-01-01

424

Reinraumtechnik fr die Medizintechnik  

NASA Astrophysics Data System (ADS)

Die Reinraumtechnik ist heute ein unverzichtbarer Bestandteil bei der Fertigung von Produkten der Life Sciences, den Bereichen Pharma, Lebensmittel, Kosmetik und Medizintechnik. In Anbetracht der langen Historie der Medizintechnik ist sie jedoch eine sehr junge Disziplin. Die Bedeutung von Keimen und die richtige Einschtzung ihrer Gre wurden zwar sehr frh bereits durch Paracelsus erkannt, jedoch wurden daraus noch keine speziellen oder kontinuierlich umgesetzten Hygienevorschriften abgeleitet. Die erste bekannte technische Umsetzung von Hygieneempfehlungen geht auf den Franzosen Franois Nicolas Appert zurck, der eine aseptische Abfllmethode fr Lebensmittel entwickelte und diese 1810 verffentlichte [1]. Die erste dokumentierte medizinische Umsetzung stellten Hygienevorschriften fr rzte dar, die Ignaz Philipp Semmelweis nach 1847 in der Wiener Klinik fr Geburtshilfe einfhrte [2].

Petek, Max; Jungbluth, Martin; Krampe, Erhard

425

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

426

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

427

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

428

The Ambiguous Dying Syndrome  

ERIC Educational Resources Information Center

More than one-half of the 2.4 million deaths that will occur in the United States in 2004 will be immediately preceded by a time in which the likelihood of dying can best be described as "ambiguous." Many people die without ever being considered "dying" or "at the end of life." These people may miss out on the opportunity to close important

Bern-Klug, Mercedes

2004-01-01

429

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

430

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

431

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.

432

The Angry Dying Patient  

PubMed Central

Over 25 years ago, Kubler-Ross identified anger as a predictable part of the dying process. When the dying patient becomes angry in the clinical setting, all types of communication become strained. Physicians can help the angry dying patient through this difficult time by using 10 rules of engagement. When physicians engage and empathize with these patients, they improve the patient's response to pain and they reduce patient suffering. When physicians educate patients on their normal responses to dying and enlist them in the process of family reconciliation, they can impact the end-of-life experience in a positive way. PMID:15014699

Houston, Robert E.

1999-01-01

433

Old soldiers never die ....  

PubMed Central

An ancestral supersoldier phenotype of Pheidole ants can be recovered when selection for supersoldiers re-emerges, indicating that the developmental potential for caste pathways is retained. PMID:22356770

2012-01-01

434

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...

435

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...

436

The effect of Sr and Fe additions on the microstructure and mechanical properties of a direct squeeze cast Al-7Si-0.3Mg alloy  

SciTech Connect

This article describes the results of an investigation into the microstructure and mechanical properties of a gravity die cast and direct squeeze cast LM25 alloy (Al-7Si-0.3Mg-0.3Fe). The direct squeeze cast LM25 alloy has superior mechanical properties compared to the gravity die cast LM25 alloy, especially with regard to ductility, which is increased from {approximately}1.7 pct for the gravity die cast LM25 alloy to {approximately}8.0 pct for the direct squeeze cast LM25 alloy in the T6 heat-treated conditions. This increase in ductility is due to (1) the removal of porosity, (2) a decrease in Si particle size, and (3) a refinement of the Fe-Si-aluminide particles. High cooling rates in direct squeeze casting result in quench modification of the Si particles, such that chemical modification with Sr or Na may not be required. In addition, direct squeeze casting is more tolerant of Fe impurities in the alloy, due to the formation of smaller Fe-Si-aluminide particles than those in gravity die cast material. The direct squeeze cast LM25 + Fe alloy (Al-7Si-0.3Mg-1.0Fe) has a ductility of {approximately}6.5 pct, compared to that of {approximately}0.5 pct for the gravity die cast LM25 + Fe alloy in the T6 heat-treated condition. This increase in tolerance to Fe impurities can lead to a substantial reduction in manufacturing costs due to (1) reduced raw-material costs, (2) reduced die sticking, and (3) improved die life.

Dong, J.X.; Karnezis, P.A.; Durrant, G.; Cantor, B. [Univ. of Oxford (United Kingdom). Dept. of Materials

1999-05-01

437

Steel castings by the electroslag casting technique. [CF8M  

SciTech Connect

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

Sikka, V.K.; Mitchell, A.

1984-01-01

438

Extrusion die and method  

DOEpatents

A method and die apparatus for manufacturing a honeycomb body of triangular cell cross-section and high cell density, the die having a combination of (i) feedholes feeding slot intersections and (ii) feedholes feeding slot segments not supplied from slot intersections, whereby a reduction in feedhole count is achieved while still retaining good extrusion efficiency and extrudate uniformity.

Lipp, G. Daniel (Painted Post, NY)

1994-05-03

439

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

440

Strain Rate Dependency of Bronze Metal Matrix Composite Mechanical Properties as a Function of Casting Technique  

Microsoft Academic Search

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

Lloyd Brown; Peter Joyce; Joshua Radice; Dro Gregorian; Michael Gobble

2011-01-01

441

A new method for casting discrepancy: some results for a phosphate-bonded investment  

Microsoft Academic Search

Objectives: An accurate and realistic casting discrepancy method applicable to base metal alloys has hitherto been lacking. The purpose of this study was to develop a method for determining casting discrepancy free of interference from oxide, slag and surface defects, working under realistic conditions. In addition, a variable was sought that could be used for calibrating the casting process to

E. K.-H. Ho; B. W. Darvell

1998-01-01

442

Peculiarities of producing decorative articles by the method of lost foam casting  

NASA Astrophysics Data System (ADS)

This paper investigates the method of lost foam casting performed with consumable patterns. The dependence of the fluidity of the silumin on the polystyrene's characteristics, casting temperature and the pattern's parameters is revealed. Recommendations regarding the application of various polystyrene types for artistic casting are provided.

Utyev, Oleg; Lukyanchenko, Anna

2014-10-01

443

Evaluation of cast creep occurring during simulated clubfoot correction.  

PubMed

The Ponseti method is a widely accepted and highly successful conservative treatment of pediatric clubfoot involving weekly manipulations and cast applications. Qualitative assessments have indicated the potential success of the technique with cast materials other than standard plaster of Paris. However, guidelines for clubfoot correction based on the mechanical response of these materials have yet to be investigated. The current study sought to characterize and compare the ability of three standard cast materials to maintain the Ponseti-corrected foot position by evaluating cast creep response. A dynamic cast testing device, built to model clubfoot correction, was wrapped in plaster of Paris, semi-rigid fiberglass, and rigid fiberglass. Three-dimensional motion responses to two joint stiffnesses were recorded. Rotational creep displacement and linearity of the limb-cast composite were analyzed. Minimal change in position over time was found for all materials. Among cast materials, the rotational creep displacement was significantly different (p < 0.0001). The most creep displacement occurred in the plaster of Paris (2.0), then the semi-rigid fiberglass (1.0), and then the rigid fiberglass (0.4). Torque magnitude did not affect creep displacement response. Analysis of normalized rotation showed quasi-linear viscoelastic behavior. This study provided a mechanical evaluation of cast material performance as used for clubfoot correction. Creep displacement dependence on cast material and insensitivity to torque were discovered. This information may provide a quantitative and mechanical basis for future innovations for clubfoot care. PMID:23636764

Cohen, Tamara L; Altiok, Haluk; Wang, Mei; McGrady, Linda M; Krzak, Joseph; Graf, Adam; Tarima, Sergey; Smith, Peter A; Harris, Gerald F

2013-08-01

444

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

445

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 440C 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

446

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

447

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, Jol; Buffiere, Jean-Yves; Charkaluk, Eric

2014-04-01

448

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

449

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

450

Die zwei Kulturen  

NASA Astrophysics Data System (ADS)

Oft werden zwei mgliche Entwicklungen des Webs diskutiert - das Web 2.0 und das Semantic Web. Wenn wir diese zwei Visionen fr das zuknftige Web unter die Lupe nehmen, dann lsst sich feststellen, dass sich die Ideen in ihrem Kern und ihren Technologien gegenseitig ergnzen. Dementsprechend knnen und sollen beide Visionen von den Erfahrungen und Strken der anderen profitieren. Wir glauben daran, dass zuknftige Webanwendungen den Web 2.0-Fokus auf Community und Benutzerfreundlichkeit beibehalten und, darber hinaus, auch von Technologien des Semantic Web zur Vereinfachung der mashuphnlichen Datenintegration profitieren werden. Auf Basis eines Semantic Blog-Szenarios werden wir hier die Vorteile einer mglichen Kombination von Semantic Web und Web 2.0 illustrieren, die zeitnah realisiert werden kann. Wir werden auch auf technische Probleme eingehen, die bei der Erweiterung dieses Szenarios entstehen. Wir stellen dar, wie aktuelle Entwicklungen in der Semantic Web Forschung diese Probleme angehen knnen, und setzen zugleich auch Schwerpunkte fr die zuknftige Forschung, die in diesem Zusammenhang relevant sind.

Ankolekar, Anupriya; Krtzsch, Markus; Tran, Than; Vrandecic, Denny

451

DIVISION 04 MASONRY 04720 CAST STONE  

E-print Network

DIVISION 04 ­ MASONRY _____________________________________________________________ 04720 CAST STONE A. Design Considerations 1. Cast stone shall comply with ASTM C1364, Standard Specification for Cast Stone. 2. Care must be taken in the design of individual units of cast stone, working within

452

Die Dispositionsqualitt einer Rettungsleitstelle  

Microsoft Academic Search

Zusammenfassung\\u000a Qualittsmanagement in der Leitstelle sollte neben quantitativen Parametern wie Zeitintervallen auch inhaltliche Fragestellungen\\u000a beleuchten. Bezogen auf den Notrufabfrage- und Dispositionsprozess wre somit die Korrelation zwischen vermuteter und tatschlicher\\u000a Notfalllage zu untersuchen. Hierzu ist eine Rckmeldung ber Art und Schwere des Notfalls erforderlich, die von dem vor\\u000a Ort agierenden Rettungsdienstpersonal an die Leitstelle bermittelt werden muss.\\u000a \\u000a \\u000a \\u000a Im hessischen Main-Kinzig-Kreis wurde

W. Lenz; M. Luderer; G. Seitz; M. Lipp

2000-01-01

453

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

454

Usefulness of gel-casting method in the fabrication of nonstoichiometric CaZrO{sub 3}-based electrolytes for high temperature application  

SciTech Connect

Hydrogels obtained from lower toxicity monomers of N-(hydroxymethyl)acrylamide and N,N'-methylenebisacrylamide were applied to form nonstoichiometric CaZrO{sub 3}-based electrolytes. A coprecipitation-calcination method with ((NH{sub 4}){sub 2}C{sub 2}O{sub 4}) in concentrated NH{sub 3} aqueous solution was used to synthesise CaZrO{sub 3} involving 51 mol.% CaO (CZ-51) powder. The gas-tight CaZrO{sub 3}-based rods were prepared by the gel-casting method with 45 vol.% suspension and then sintered at 1500 deg. C-2 h. It was found that in low oxygen partial pressure, the nonstoichiometric CaZrO{sub 3} obtained by gel-casting method were pure oxide ion conductors. These samples exhibited comparable electrical conductivity values to isostatically compressed pellets starting from the same powder. The results of experiments on thermochemical stability of CZ-51 gel-cast shapes at high temperatures in air or gas mixtures involving 2-50 vol.% H{sub 2}, as well as the corrosion resistance in exhaust gases from a self-ignition engine were also presented and discussed. The thermal resistance of CaZrO{sub 3} obtained rods against molten nickel or iron was also examined. Based upon these investigations, it is evident that only in hydrogen-rich gas atmospheres can the stability of CaZrO{sub 3} shapes be limited due to the presence of CaO precipitation as a second phase. The nonstoichiometric CaZrO{sub 3} (CZ-51) gel-cast materials were also tested in solid galvanic cells, designed to study thermodynamic properties of oxide materials, important for SOFC and energy technology devices. In this way, the Gibbs energy of NiM{sub 2}O{sub 4}, M = Cr, Fe, at 650-1000 deg. C was determined. The CaZrO{sub 3} involving 51 mol.% CaO gel-cast sintered shapes seems to be promising solid electrolytes for electrochemical oxygen probes in control of metal processing and thermodynamic studies of materials important for the development of the energy industry.

Dudek, Magdalena [AGH - University of Science and Technology, Faculty of Energy and Fuels, 30-059 Cracow (Poland)

2009-09-15

455

Cool Cast Facts  

MedlinePLUS

... may tell you to cover it with a plastic bag while you shower or you can get a special waterproof sleeve to cover it. Depending on where your cast or splint is on your body, you may find it easier to take a ...

456

ber die Lumineszenz der Alkalivanadate  

Microsoft Academic Search

Zusammenfassung Die aus einer Alkalikarbonatlsung mit V2O5 ohne Zusatz von Aktivatoren prparierten Alkalimetavanadate zeigen mit Ausnahme des Lithiumvanadats unter Ultraviolettanregung eine gelbe bis grne Lumineszenz. Die Lumineszenzausbeute steigt mit zunehmendem Atomgewicht des Alkali-Ions und erreicht beim CsVO3 die Helligkeit von gut prparierten Zinkcadmiumsulfiden. Emissions- und Absorptionsspektren, die Temperaturabhngigkeit der Quantenausbeute, die Temperaturabhngigkeit der Emissionsbanden, die Erregungsverteilung und das Verhalten unter

H. Gobrecht; G. Heinsohn

1957-01-01

457

Study and prevention of cracking during weld-repair of heat-resistant cast steels  

Microsoft Academic Search

Heat-resistant cast steels are highly sensitive to cracking as they are weld-repaired because of their very low ductility. To prevent weld-repair cracking of three different heat-resistant cast steels used for the manufacturing of superplastic forming (SPF) dies, the effect of various welding parameters, such as the choice of the filler material, the number of weld passes and the pre-heating temperature

T. Branza; F. Deschaux-Beaume; G. Sierra; P. Lours

2009-01-01

458