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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

Application of an integrated CAD\\/CAE\\/CAM system for die casting dies  

Microsoft Academic Search

According to the concept of concurrent engineering (CE), a CAD\\/CAE\\/CAM integrated system for die casting dies is established and applied in the primary stage. The platform of the Pro\\/ENGINEER CAD\\/CAM software, the MAGMASOFT simulation software and a primary expert system for the design of the die casting process are available to establish this integrated system. A primary expert system package

Shuhua Yue; Guoxiang Wang; Fei Yin; Yixin Wang; Jiangbo Yang

2003-01-01

3

Casting Characteristics of Aluminum Die Casting Alloys  

Microsoft Academic Search

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

Makhlouf M. Makhlouf; Diran Apelian

2002-01-01

4

Fatigue properties of die cast zinc alloys for automotive lock applications  

SciTech Connect

During the 1970’s 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

5

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

6

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

7

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

8

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

NASA Astrophysics Data System (ADS)

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

Birol, Yücel; Birol, Feriha

2007-04-01

9

Application of Nonlinear Superposition to Creep and Relaxation of Commercial Die-Casting Aluminum Alloys  

NASA Astrophysics Data System (ADS)

Die-cast aluminum alloys are heavily used in small engines, where they are subjected to long-term stresses at elevated temperatures. The resulting time-dependent material responses can result in inefficient engine operation and failure. A method to analytically determine the stress relaxation response directly from creep tests and to accurately interpolate between experimental time-history curves would be of great value. Constant strain, stress relaxation tests and constant load, creep tests were conducted on aluminum die-casting alloys: B-390, eutectic Al Si and a 17% Si Al alloy. A nonlinear superposition integral was used to (i) interpolate between empirical primary inelastic creep-strain and stress-relaxation time histories and (ii) to determine the stress relaxation response from corresponding creep data. Using isochronal stress-strain curves, prediction of the creep response at an intermediate stress level from empirical creep curves at higher and lower stresses resulted in a correlation (R) of 0.98. Similarly for relaxation, correlations of 0.98 were obtained for the prediction of an intermediate strain level curve from higher and lower empirical relaxation curves. The theoretical prediction of stress relaxation from empirical creep curves fell within 10% of experimental data.

Oza, Ashish; Jaglinski, Tim; Vanderby, Ray; Lakes, Roderic S.

2004-12-01

10

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

11

Applications for the strontium treatment of wrought and die-cast Al  

NASA Astrophysics Data System (ADS)

Strontium is well known for its ability to modify the eutectic silicon phase in aluminum-silicon foundry alloys. More recently, however, it has been established that strontium also stabilizes the more desirable ? iron-bearing intermetallic phase in 6XXX series wrought aluminum alloys. As a result, lengthy billet homogenization times that are normally required to transform the acicular ? iron-bearing intermetallic phase to the ? phase can be shortened significantly. In the case of the foundry alloys, strontium additions to a 380 alloy were found to increase the pressure tightness of high-pressure die castings by as much as 60%. This improvement is believed to occur as a result of improved metal flow with the strontium addition causing a reduction in the size of the entrapped air pores and the refinement of sludge particles.

Kulunk, B.; Zuliani, D. J.

1996-10-01

12

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

13

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

14

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

15

Vacuum die Casting of Silicon Sheet for Photovoltaic Applications. First Quarterly Report, March 16-June 30, 1979.  

National Technical Information Service (NTIS)

The obtective of this program is to develop a vacuum die-casting process for producing silicon sheet suitable for photovoltaic cells and to develop production techniques for optimization of polycrystallie silicon solar cell output. Efforts will examine pr...

1979-01-01

16

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

17

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

18

Automated Radioscopic Inspection of Aluminum Die Castings  

Microsoft Academic Search

Castings produced for the automotive industry are c onsidered important components for overall roadworthiness. To ensure the safety of con struction, it is necessary to check every part thoroughly using non-destructive testing . Radioscopy rapidly became the accepted way for controlling the quality of die cas t pieces. In this paper the fundamental principles of the automated detection of casting

Domingo Mery

19

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

Microsoft Academic Search

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

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

1995-01-01

20

Spray-formed Tooling for Injection Molding and Die Casting Applications  

SciTech Connect

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

Mc Hugh, Kevin Matthew

2000-06-01

21

Heat-Transfer Coefficient and In-Cavity Pressure at the Casting-Die Interface during High-Pressure Die Casting of the Magnesium Alloy AZ91D  

NASA Astrophysics Data System (ADS)

The present article deals with the application of a new measurement method to determine the heat-transfer coefficient (HTC) and the heat flux density at the casting-die interface during high-pressure die casting (HPDC) and solidification of the magnesium AZ91D alloy. The main measurements during the trial included velocity and the position of the piston that delivers the metal into the die, the pressure in the die cavity and at the tip of the piston, the alloy surface temperature, and the die temperature at different depths from the surface of the die. The temperature data were analyzed using an inverse method to determine the HTC at the casting-die interface during solidification. This article examines in detail the influence of the piston velocity and in-cavity pressure on heat transfer at the casting-die interface during casting and solidification of the magnesium AZ91D alloy.

Hamasaiid, A.; Dour, G.; Dargusch, M. S.; Loulou, T.; Davidson, C.; Savage, G.

2008-04-01

22

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

23

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

24

Modeling of high temperature- and diffusion-controlled die soldering in aluminum high pressure die casting  

Microsoft Academic Search

Soldering of cast alloys to the dies has been a continuing source of die surface damage in the aluminum die-casting industry. To reduce the repair and maintenance costs, an approach to modeling the damage and predicting the die lifetime is required. The aim of the present study is the estimation of the die lifetime based on a quantitative analysis of

K. Domkin; J. H. Hattel; J. Thorborg

2009-01-01

25

Vacuum-Die casting titanium for aerospace and commercial components  

NASA Astrophysics Data System (ADS)

Vacuum-die casting offers a high-quality, low-cost alternative for manufacturing titanium components. Lower costs are obtained through the elimination of processing steps that are associated with other manufacturing methods, such as investment casting. However, vacuum-die-cast component geometry is limited to single-plane, solid components weighing less than 18 kg. Initial mechanical property tests performed on vacuum-die-cast Ti-6Al-4V show properties similar to that of wrought material, which could lead to the direct substitution of vacuum-die casting components for wrought components. Additionally, the quality of vacuum-die-cast components shows improvement over investment castings through the elimination of alpha-case and the use of a ceramic-less casting system.

Larsen, Don; Colvin, Greg

1999-06-01

26

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

27

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

28

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

29

Computer Aided Manufacturability Analysis of Die-cast Parts  

Microsoft Academic Search

Automated manufacturability analysis is an important tool with the designer which is meant to incorporate manufacturability aspects at initial stages of design. This paper deals with a system developed for automated manufacturability analysis for die-cast parts. Purpose of this system is to assist designers in their effort to come up with manufacturable die-cast parts economizing in terms of cost and

J. Madan; P. V. M. Rao; T. K. Kundra

2007-01-01

30

Die erosion and its effect on soldering formation in high pressure die casting of aluminium alloys  

Microsoft Academic Search

Erosion of the die material during die filling has long been regarded as a possible damage mechanism of dies in high pressure die casting (HPDC) of aluminium alloys. Melt impingement and erosion have also been proposed to be an important step leading to die soldering. However, there is little information in the literature on the direct measurement of any kind

Z. W Chen; M. Z Jahedi

1999-01-01

31

Modern steels for pressure die-casting molds  

Microsoft Academic Search

1.The service life of pressure die-casting molds can be improved substantially by using corrosion resistant steels in place of the heat resistant die steels used at the present time.2.The heat resistance of corrosion resistant steels can be improved by alloying with molybdenum and tungsten.3.Steels 18Kh12VMBFR, 2Kh9V6, and 4Kh4MVFS are the most suitable for pressure die-casting molds used for copper alloys,

Yu. A. Geller; E. S. Golubeva; A. I. Goncharova

1975-01-01

32

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

Microsoft Academic Search

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 \\

Yongyou Cao; Zhipeng Guo; Shoumei Xiong

2012-01-01

33

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

34

Numerical simulation of low pressure die-casting aluminum wheel  

Microsoft Academic Search

The FDM numerical simulation software, ViewCast system, was employed to simulate the low pressure die casting (LPDC) of an aluminum wheel. By analyzing the mold-fi lling and solidifi cation stage of the LPDC process, the distribution of liquid fraction, temperature field and solidification pattern of castings were studied. The potential shrinkage defects were predicted to be formed at the rim\\/spoke

Mi Guofa; Liu Xiangyu; Wang Kuangfei; Fu Hengzhi

35

Optimization of Sprue Shape for Die Casting Using CFD Simulator  

NASA Astrophysics Data System (ADS)

Computational fluid dynamics (CFD) simulators have recently been used for optimization in die casting and various other fields. However, solving an optimization problem with a CFD simulator (CFD optimization problem) has the issue of uncertainty in the evaluated values from the CFD simulations. Such problems are, of course, difficult to optimize compared to general problems. In this paper, we propose an optimization algorithm that can search for good solutions to CFD optimization problems. We have appliedthe algorithm to the optimization of the sprue shape for die casting at an actual plant.

Kanazawa, Ken'Ichi; Yano, Ken'Ichi

36

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

37

Microstructures and properties of aluminum die casting alloys  

Microsoft Academic Search

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

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

1998-01-01

38

An indicator for fitting castings to a die.  

PubMed

This article describes a procedure for making an indicator to be used in fitting a casting to a die. It also describes how to use the indicator in the laboratory. The materials for making the indicator are inexpensive, present no health hazard, and are readily available at any arts and crafts store. PMID:1403953

Troendle, G R; Troendle, K B

1992-10-01

39

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

40

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

41

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

42

Isothermal Forging of Titanium Alloys Using Large Precision-Cast Dies.  

National Technical Information Service (NTIS)

The technology of isothermal forging of titanium alloys in large precision-cast dies was established. Twelve forging die castings were produced in the range of 200 to 1400 lb per die half. MAR-M 200 and IN-100 nickel-base superalloys were selected as die ...

K. M. Kulkarni N. M. Parikh T. Watmough

1970-01-01

43

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

44

Application of Rapid Prototyping Technology in Die Making of Diesel Engine  

Microsoft Academic Search

This paper studies engineering applications of rapid prototyping (RP) technology in die making of diesel engine. On demand of product development and die making of, an integrated system of reverse engineering and rapid prototyping (RE\\/RP) for engineering application is constructed, and effective application of RP technology in die making is thus realized. Taking the casting die for clutch house of

Yu Zhang; Hongwu Liu

2009-01-01

45

Heat Treatment of High-Pressure Die Castings  

NASA Astrophysics Data System (ADS)

High-pressure die-cast Al alloys cannot normally be heated at high temperatures due to the presence of pores containing entrapped gases, which lead to the formation of surface blisters. It has been found that blistering can be avoided by using considerably shorter solution-treatment times and lower temperatures. Experiments with alloys 360 (Al-9.5Si-0.5Mg) and 380 (Al-8.5Si-3.5Cu) have shown that strong responses to age hardening are still possible following these modified solution treatments.[1-3] For T6 tempers, increases in 0.2 pct proof stress of 80 pct for 360 and 115 pct for 380 have been obtained compared with as-cast values. Using a T4 temper, ductility is improved without any sacrifice in strength.

Lumley, R. N.; O'Donnell, R. G.; Gunasegaram, D. R.; Givord, M.

2007-10-01

46

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

47

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

48

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

49

Thermal Stress Analysis for Ceramics Stalk in the Low Pressure Die Casting Machine  

Microsoft Academic Search

Low pressure die casting (LPDC) is defined as a net shape casting technology in which the molten metal is injected at high speeds and pressure into a metallic die. The LPDC process is playing an increasingly important role in the foundry industry as a low-cost and high-efficiency precision forming technique. The LPDC process is that the permanent die and filling

Nao-Aki Noda; Nao-Aki Hendra; Yasushi Takase; Wenbin Li

2009-01-01

50

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

51

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

52

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

53

Interfacial Heat Transfer during Die Casting of an Al-Si-Cu Alloy  

NASA Astrophysics Data System (ADS)

The relationship between in-cavity pressure, heat flux, and heat-transfer coefficient during high-pressure die casting of an Al-9 pct Si-3 pct Cu alloy was investigated. Detailed measurements were performed using infrared probes and thermocouple arrays that accurately determine both casting and die surface temperatures during the pressure die casting of an aluminum A380 alloy. Concurrent in-cavity pressure measurements were also performed. These measurements enabled the correlation between in-cavity pressure and accurate heat-transfer coefficients in high-pressure die-casting operations.

Hamasaiid, A.; Wang, G.; Davidson, C.; Dour, G.; Dargusch, M. S.

2009-12-01

54

Maximizing average efficiency of process time for pressure die casting in real foundries  

Microsoft Academic Search

Scheduling of casting processes is the problem of determining the number of products that will be manufactured in each casting\\u000a shift so as to optimize a predetermined objective function. In this paper, we propose a linear programming (LP) model that\\u000a maximizes the average efficiency of process time for casting in real foundries. The considered casting process is pressure\\u000a die casting,

Yong Kuk Park; Jung-Min Yang

2011-01-01

55

Investment cast AISI H13 tooling for automotive applications  

Microsoft Academic Search

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

M. C. Maguire; M. D. Baldwin; P. W. Hochanadel; G. R. Edwards

1995-01-01

56

Mechanism and preventive measures for die soldering during Al casting in a ferrous mold  

NASA Astrophysics Data System (ADS)

This work provides a comprehensive understanding of the reactions at the ferrous die/molten metal interface in a metal mold casting operation. The literature has shown that several important factors influence reactions at the ferrous die/molten aluminum interface, including temperature of the melt, temperature of the die, alloy chemistry of the melt and die, die surface engineering, topographical features, and coatings. This article discusses the effect of the more critical factors on soldering, based on the authors’ investigations. Inaddition, based on a mechanistic understanding of the interface reactions between ferrous die and molten aluminum, recommendations are given for specific processing issues to alleviate soldering during die casting of aluminum alloys.

Shankar, Sumanth; Apelian, Diran

2002-08-01

57

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 sprue–runner 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

58

Optimization of a Wear Property of Die Cast AZ91D Components via a Neural Network  

Microsoft Academic Search

This study integrated a trained general regression neural network (GRNN) and a sequential quadratic programming (SQP) method to determine an optimal parameter setting for a die casting process of AZ91D. Nine experiments were prepared under different die casting processes by selecting slurry pressure, the fusion slurry velocity and the mold temperature as three controlled parameters and the wear mass loss

Jeong-Lian Wen; Jie-Ren Shie; Yung-Kuang Yang

2009-01-01

59

Effect of Alloying Elements on Thermal Wear of Cast Hot-Forging Die Steels  

Microsoft Academic Search

The effect of main alloying elements on thermal wear of cast hot-forging die steels was studied. The wear mechanism was discussed. The results show that alloying elements have significant influences on the thermal wear of cast hot-forging die steels. The wear rates decrease with an increase in chromium content from 3% to 4% and molybdenum content from 2% to 3%,

Shu-qi WANG; Kang-min CHEN; Xiang-hong CUI; Qi-chuan JIANG; Bian HONG

2006-01-01

60

Investigation of erosive-corrosive wear in the low pressure die casting of aluminum A356  

Microsoft Academic Search

Die surfaces are exposed to a wide range of operating conditions during permanent mould casting. The combination of materials, temperature, pressure, and flow can result in erosive-corrosive wear. The resulting accelerated wear can be a recurring problem along the sprue exit surface during the low pressure die casting of aluminum A356 wheels. The primary factor determining the occurrence of wear

A. E. Miller; D. M. Maijer

2006-01-01

61

Mechanical and wear properties of rheocast and conventional gravity die cast A356 alloy  

Microsoft Academic Search

A356 alloy produced by means of conventional gravity die casting and rheocasting has been investigated and their microstructure, mechanical and tribological properties were compared. The microstructure of conventional cast sample is fully dendritic in contrast to spheroidal morphology in rheocast sample. The mechanical properties of the rheocast samples are considerably higher than the conventional cast samples. The volumetric wear loss

A. K. Dey; P. Poddar; K. K. Singh; K. L. Sahoo

2006-01-01

62

Die Materials for Critical Applications and Increased Production Rates  

SciTech Connect

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

David Schwam; John Wallace; Sebastian Birceanu

2002-11-30

63

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

64

Investment cast AISI H13 tooling for automotive applications.  

National Technical Information Service (NTIS)

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 mate...

M. C. Maguire M. D. Baldwin P. W. Hochanadel G. R. Edwards

1995-01-01

65

Melt-Conditioned, High-Pressure Die Casting of Mg-Zn-Y Alloy  

NASA Astrophysics Data System (ADS)

The liquid Mg-Zn-Y alloy was conditioned by an application of high-intensive shearing with a pair of intermesh twin screws prior to high-pressure die casting (HPDC). Melt conditioning produces a uniform microstructure with fine grain size and high integrity. The microstructure was analyzed thoroughly, and the solidification characteristics of the melt-conditioned HPDC (MC-HPDC) structure were discussed. The enhancement in I-phase precipitation and the improvement in mechanical properties of MC-HPDC Mg-Zn-Y alloy can be achieved through cyclic annealing.

Xia, Mingxu; Mitra, Subhajit; Dhindaw, Brij; Liu, Guojun; Fan, Zhongyun

2010-02-01

66

Effect of Process Parameters, Casting Thickness, and Alloys on the Interfacial Heat-Transfer Coefficient in the High-Pressure Die-Casting Process  

NASA Astrophysics Data System (ADS)

The heat transfer at the metal-die interface is believed to have great influence on the solidification process and cast structure of the high-pressure die-casting (HPDC) process. The present article focused on the effects of process parameters, casting thickness, and alloys on the metal-die interfacial heat-transfer coefficient (IHTC) in the HPDC process. Experiment was carried out on a cold-chamber die-casting machine with two casting alloys AM50 and ADC12. A special casting, namely, “step-shape” casting, was used and cast against a H13 steel die. The IHTC was determined using an inverse approach based on the temperature measurements inside the die. Results show that the IHTC is different at different steps and changes as the solidification of the casting proceeds. Process parameters only influence the IHTC in its peak value, and for both AM50 and ADC12 alloys, a greater fast shot velocity leads to a greater IHTC peak value at steps 1 and 2. The initial die surface temperature has a more prominent influence on the IHTC peak values at the thicker steps, especially step 5. Results also show that a closer contact between the casting and die could be achieved when the casting alloy is ADC12 instead of AM50, which consequently leads to a higher IHTC.

Guo, Zhi-Peng; Xiong, Shou-Mei; Liu, Bai-Cheng; Li, Mei; Allison, John

2008-12-01

67

The Effects of Die Relief Agent on the Retention of Full Coverage Castings.  

National Technical Information Service (NTIS)

The effect of the use of a proprietary die relief agent on the retention of castings cemented with zinc phosphate, a zinc polycarboxylate or a modified zinc oxide-eugenol cement was studied. Forces required to dislodge non-relieved castings from tooth pre...

S. G. Vermilyea M. J. Kuffler E. F. Huget

1981-01-01

68

Determination of wax pattern die profile for investment casting of turbine blades  

Microsoft Academic Search

In order to conform to dimensional tolerances, an efficient numerical method, displacement iterative compensation method, based on finite element methodology (FEM) was presented for the wax pattern die profile design of turbine blades. Casting shrinkages at different positions of the blade which was considered nonlinear thermo-mechanical casting deformations were calculated. Based on the displacement iterative compensation method proposed, the optimized

Yi-wei DONG; Kun BU; Yang-qing DOU; Ding-hua ZHANG

2011-01-01

69

The Microstructure of Direct Squeeze Cast and Gravity Die Cast 7050 (Al–6.2Zn–2.3Cu–2.3Mg) Wrought Al Alloy  

Microsoft Academic Search

A 7050 (Al–6.2 wt% Zn–2.3 wt% Cu–2.3 wt% Mg) Al alloy, conventionally used for wrought products, has been successfully cast to near-net shape using direct squeeze casting. Squeeze casting with an applied pressure of 50 MPa removes the defects observed in gravity die cast billets, in particular, (1) shrinkage pipe, (2) poor die replication and waisting, and (3) microporosity. Squeeze

S. W. Kim; G. Durrant; J. H. Lee; B. Cantor

1998-01-01

70

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

71

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

National Technical Information Service (NTIS)

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 prem...

P. W. Hochanadel G. R. Edwards M. C. Maguire M. D. Baldwin

1995-01-01

72

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

73

Evaluation of Die Forging of Ductile Cast Iron.  

National Technical Information Service (NTIS)

The report describes tests of the forgeability of ductile cast iron in the 1,700 to 1,950 range. It was found that while scaling is minimal, ductile iron is less plastic and requires more time and force for a given reduction than does steel forged at the ...

J. W. Spretnak D. E. Tilton S. Eliot S. J. Kiefer R. T. Herdegen

1977-01-01

74

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

Microsoft Academic Search

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

Soon Gi Lee

2006-01-01

75

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

76

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

Microsoft Academic Search

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

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

2007-01-01

77

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

78

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

SciTech Connect

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

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

2004-10-01

79

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

80

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

81

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

82

Predicting compositions and properties of aluminum die casting alloys using artificial neural network  

Microsoft Academic Search

Despite the large numbe r of ex isting alloys and alloy databases, identifying proper alloys for spe cific ap plicat io ns still remains a challenge. In order to facilitate the selection and prediction of aluminum die casting alloys and their properties, an electronic database - \\

L. Wang; D. Apelian; M. Ma; W. Huang

83

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

84

Corrosion resistance of aged die cast magnesium alloy AZ91D  

Microsoft Academic Search

The corrosion behaviour of die cast magnesium alloy AZ91D aged at 160°C 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

85

ALEXSYS - A Prototype Knowledge Based Expert System for the Quality Assurance of High Pressure Die Castings  

Microsoft Academic Search

The ALEXSYS System is aimed to be used as an industrial tool for the identification, assessment and correction of defects in the aluminium high pressure die casting industry. ALEXSYS consists of three modules: the Diagnostic Module, the Machine Parameters Module and the Design Module. The expert system is tested within a real industrial environment, where a robotic cell fully equipped

C. A. G. Webster; M. Weller; M. M. Sfantsikopoulos; V. D. Tsoukalas

1993-01-01

86

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

87

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

88

Fatigue Crack Growth Mechanisms in High-Pressure Die-Cast Magnesium Alloys  

NASA Astrophysics Data System (ADS)

Microstructure-affected micromechanisms of fatigue crack growth operating near the limit plasticity regime were experimentally identified for the four main commercial high-pressure die-cast (HPDC) magnesium alloys: AM50, AM60, AZ91, and AE44. These fatigue micromechanisms manifested by the concomitant effects of casting pores, interdendritic Al-rich solid solution layer, ?-phase particles, Mn-rich inclusions, rare earth-rich intermetallics, dendrite cell size, and surface segregation phenomena. These concomitant mechanisms clearly delineated the fatigue durability observed for the AM50, AM60, AZ91, and AE44 Mg alloys in both the low- and high-cycle fatigue regimes.

El Kadiri, Haitham; Horstemeyer, M. F.; Jordon, J. B.; Xue, Yibin

2008-01-01

89

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

90

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

91

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

NASA Astrophysics Data System (ADS)

Bands of positive macrosegregation and porosity commonly follow the surface contour of components produced by high-pressure die casting (HPDC). In this article, Al alloy AlSi7Mg and Mg alloys AZ91 and AM60 were cast into tensile test bars using cold-chamber (cc) HPDC. Microstructural characterization revealed that externally solidified crystals (ESCs) are not necessary for defect band formation, and that defect bands can form both near to and relatively far from any surface layer of different microstructure. The defect bands were 140 to 240 ?m thick. In addition to defect-band-related macrosegregation, the castings also contained inverse segregation and surface segregation. Defect bands are shown to have the characteristics of the dilatant shear bands reported in past rheology studies, indicating that defect bands form due to strain localization in partially solid material during the HPDC process.

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

2007-08-01

92

Feasibility of semi-solid die casting of ADC12 aluminum alloy  

Microsoft Academic Search

The feasibility of semi-solid die casting of ADC12 aluminum alloy was studied. The effects of plunger speed, gate thickness, and solid fraction of the slurry on the defects were determined. The defects investigated are gas and shrinkage porosity. In the experiments, semi-solid slurry was prepared by the gas-induced semi-solid (GISS) technique. Then, the slurry was transferred to the shot sleeve

S. JANUDOM; T. RATTANOCHAIKUL; R. BURAPA; S. WISUTMETHANGOON; J. WANNASIN

2010-01-01

93

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

94

Compressive strain-rate sensitivity of magnesium–aluminum die casting alloys  

Microsoft Academic Search

Compressive properties of three die cast magnesium alloys (AM20, AM50, and AM60) have been investigated at a nominal strain rate range from 0.001s?1 to approximately 1700s?1. The high strain rate experiments were conducted using a Split Hopkinson Bar apparatus. The strain rate sensitivity decreased with increasing Al content at the low strain rates. At strain rates above 1500s?1 there was

Wei Qian Song; Peter Beggs; Mark Easton

2009-01-01

95

Creep deformation mechanisms in high-pressure die-cast magnesium-aluminum-base alloys  

Microsoft Academic Search

Creep of die-cast Mg alloys is described as an integral part of their plastic deformation behavior in terms of stress-strain-rate-strain\\u000a relations. Creep tests yield information on yield stress, work hardening, maximum deformation resistance (minimum creep rate),\\u000a and work softening. Testing in compression avoids influences by fracture. Data on the alloy AJ52 (5Al, 2Sr) in the temperature\\u000a range between 135 °C

W. Blum; Y. J. Li; X. H. Zeng; P. Zhang; B. von Großmann; C. Haberling

2005-01-01

96

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 coating•3 ?m TiN coating•0.5 ?m plasma anodisation layer and 3 ?m Al2O3 coatingThe

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

2005-01-01

97

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

PubMed

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

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

2006-06-20

98

Thermal Stress Analysis for Ceramics Stalk in the Low Pressure Die Casting Machine  

NASA Astrophysics Data System (ADS)

Low pressure die casting (LPDC) is defined as a net shape casting technology in which the molten metal is injected at high speeds and pressure into a metallic die. The LPDC process is playing an increasingly important role in the foundry industry as a low-cost and high-efficiency precision forming technique. The LPDC process is that the permanent die and filling systems are placed over the furnace containing the molten alloy. The filling of the cavity is obtained by forcing the molten metal by means of a pressurized gas in order to rise into a ceramic tube, which connects the die to the furnace. The ceramics tube called stalk has high temperature resistance and high corrosion resistance. However, attention should be paid to the thermal stress when the stalk is dipped into the molten aluminum. It is important to develop the design of the stalk to reduce the risk of fracture because of low fracture toughness of ceramics. In this paper, therefore, the finite element method is applied to calculate the thermal stresses when the stalk is dipped into the crucible by varying the dipping speeds and dipping directions. It is found that the thermal stress can be reduced by dipping slowly if the stalk is dipped into the crucible vertically, while the thermal stress can be reduced by dipping fast if it is dipped horizontally.

Noda, Nao-Aki; Hendra, Nao-Aki; Takase, Yasushi; Li, Wenbin

99

The use of images in a language- and culture-independent expert system for diagnosing pressure die-casting defects  

Microsoft Academic Search

Under the overall title of ALEXSYS, two related knowledge-based systems have been produced for aluminium pressure die-casters. One is used for the diagnosis of the causes of defects in castings and suggests remedial process parameter adjustments. The second is intended for use at the design stage to given ab initio improvement in casting quality and reduced die run-in time. The

C. A. G. Webster

1995-01-01

100

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

101

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

102

The effect of die geometry on the microstructure of indirect squeeze cast and gravity die cast 7050 (Al6.2Zn2.3Cu2.3Mg) wrought Al alloy  

Microsoft Academic Search

The indirect squeeze casting process has been used to cast a 7050 (Al-6.2Zn-2.3Cu-2.3Mg) wrought Al alloy to near-net shape\\u000a with excellent die replication. Defects which occur with gravity casting, in particular (1) shrinkage pipe, (2) macro-porosity\\u000a and (3) hot-tearing, are largely removed by squeeze casting, although regions of macro-porosity can re-appear when thick sections\\u000a are fed through substantially thinner sections.

S-W Kim; G. Durrant; J-H Lee; B. Cantor

1999-01-01

103

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

104

Sliding wear and friction characteristics of six Zn-based die-casting alloys  

Microsoft Academic Search

The friction and wear characteristics of zinc-based alloys in warm, oil-lubricated, sliding contact against mild steel were investigated. The alloys, their compositions, and their microstructures included: pure Zn (100% Zn, ? zinc), Zamak 3 (Zn?4Al?0.1Cu, ? zinc plus ?? eutectic), ZA 27 (Zn?31Al?2.3Cu, ? aluminum plus ?ga eutectic), ACuZinc 5 (Zn?3.0Al?5Cu) in die cast form, and ACuZinc 10 (Zn?3.5Al?10Cu, epsilon

M. D. Hanna; J. T. Carter; M. S. Rashid

1997-01-01

105

Invloed van Procesvariabelen OP de Interne Kwaliteit van een Aluminium Spuitgietstuk (The Effect of Process Parameters on the Internal Quality of an Aluminum die Casting).  

National Technical Information Service (NTIS)

The influence of process parameters on the porosity of an aluminum die casting was investigated. Two types of die one of which had an interchangeable gate and two alloys, AlSi8Cu3 and AlSi7, were used. During the solidification phase of a die casting, air...

M. C. A. J. Dewit

1986-01-01

106

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

107

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

108

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

109

Influence of injection parameters on defects formation in die casting Al12Si1,3Cu alloy: Experimental results and numeric simulation  

Microsoft Academic Search

This paper describes the results obtained in a study performed in partnership between LabFund\\/DEM\\/PGCEM\\/UDESC and the WEG Motors Department of Industrial Engineering for the Quality Control and Aluminum Die Casting. It involves the combination of an experimental DOE (design of experiments) methodology and of a commercial numeric applicative. The influence of the speed injection parameters in the first and second

Guilherme Ourique Verran; Rui Patrick Konrad Mendes; Marco Aurélio Rossi

2006-01-01

110

Application of TRIZ Theory in Patternless Casting Manufacturing Technique  

NASA Astrophysics Data System (ADS)

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

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

111

The Use of Friction Stir Technology to Modify Surfaces of AM60B Magnesium Die Castings  

SciTech Connect

These experiments were done to evaluate the feasibility of locally modifying the surface properties of magnesium alloys with friction-stir processing. The magnesium alloy used for the study was high-pressure die-cast AM60B, nominally Mg-6Al-0.13 Mn (wt.%). Friction-stir passes were made with a translation speed of 1.7 mm/s using tool-rotation speeds of 1,250 rpm or 2,500 rpm. Stir passes with good appearance were obtained under both conditions. In some cases up to five passes were overlapped on a single bar to produce stir zones with cross-sectional dimensions of about 1.5 mm x 10 mm. Metallographic examinations indicated that the stir zones were largely comprised of a magnesium solid solution with equiaxed grains on the order of 5-10 {micro}m in size. Hardness mapping showed that the stir zones experienced increases of 16-25% compared to the as-cast metal. Room-temperature testing showed that, compared to the cast metal, the stir zones had flow stresses nearly 20% higher with about twice the tensile elongation.

Santella, Michael L [ORNL; Degen, Cassandra [South Dakota School of Mines and Technology; Frederick, David Alan [ORNL; Pan, Dr. Tsung-Yu [Ford Motor Company

2006-01-01

112

Modifying AM60B Magnesium Alloy Die Cast Surfaces by Friction Stir Processing  

SciTech Connect

These experiments were done to evaluate the feasibility of locally modifying the surface properties of magnesium alloys with friction-stir processing. The magnesium alloy used for the study was high-pressure die-cast AM60B, nominally Mg-6Al-0.13 Mn (wt. %). Friction-stir passes were made with a translation speed of 1.7 mm/s using tool-rotation speeds of 1,250 rpm or 2,500 rpm. Stir passes with good appearance were obtained under both conditions. In some cases up to five passes were overlapped on a single bar to produce stir zones with cross-sectional dimensions of about 1.5 mm x 10 mm. Metallographic examinations indicated that the stir zones were largely comprised of a magnesium solid solution with equiaxed grains on the order of 5-10 {micro}m in size. Hardness mapping showed that the stir zones experienced increases of 16-25% compared to the as-cast metal. Room-temperature testing showed that, compared to the cast metal, the stir zones had flow stresses nearly 20% higher with about twice the tensile elongation.

Santella, Michael L [ORNL; Feng, Zhili [ORNL; Degen, Cassandra [South Dakota School of Mines and Technology; Pan, Dr. Tsung-Yu [Ford Motor Company

2006-01-01

113

Improved design and durability of aluminum die casting horizontal shot sleeves  

NASA Astrophysics Data System (ADS)

The design and performance of shot sleeves is critical in meeting the engineering requirements of aluminum die cast parts. Improvement in shot sleeve materials have a major impact on dimensional stability, reproducibility and quality of the product. This investigation was undertaken in order to improve the life of aluminum die casting horizontal shot sleeves. Preliminary pin tests were run to evaluate the soldering, wash-out and thermal fatigue behavior of commercially available materials and coatings. An experimental rig was designed and constructed for shot sleeve configuration evaluation. Fabrication and testing of experimental shot sleeves was based upon preliminary results and manufacturing costs. Three shot sleeve designs and materials were compared to a reference nitrided H13 sleeve. Nitrided H13 is the preferred material for aluminum die casting shot sleeves because of wear resistance, strength and relative good soldering and wash-out resistance. The study was directed towards damage evaluation on the area under the pouring hole. This area is the most susceptible to damage because of high temperatures and impingement of molten aluminum. The results of this study showed that tungsten and molybdenum had the least amount of soldering and wash-out damage, and the best thermal fatigue resistance. Low solubility in molten aluminum and stability of intermetallic layers are main factors that determine the soldering and wash-out behavior. Thermal conductivity and thermal expansion coefficient directly influence thermal fatigue behavior. TiAlN nanolayered coating was chosen as the material with the best damage resistance among several commercial PVD coatings, because of relatively large thickness and simple deposition conditions. The results show that molybdenum thermal sprayed coating provided the best protection against damage under the pouring hole. Improved bonding is however required for life extension of the coating. TiAlN PVD coating applied on H13 nitrided substrate performed very well as long as the coating was maintained. Nitrided H13 sleeve showed extensive damage that occurred as early as 200 cycles. The nitrided layer only slowed down the diffusion process and dissolution took place at a higher rate as soon as the layer wore off. Stellite 6 sleeve also showed considerable wear under the action of molten aluminum.

Birceanu, Sebastian

114

CONTROLLED DIFFUSION SOLIDIFICATION: APPLICATION TO METAL CASTING  

Microsoft Academic Search

Wrought aluminum-based alloys exhibit superior physical and mechanical properties compared to conventional cast alloys. However, wrought alloys cannot be cast because they develop hot tears and hot cracks during solidification. For this reason, these alloys are typically cast into ingots and are subsequently brought to final shape by mechanical processes such as rolling, extrusion, drawing and forging. Controlled Diffusion Solidification

K. Symeonidis; D. Apelian; M. M. Makhlouf

115

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

116

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

117

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

SciTech Connect

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

NONE

1994-11-01

118

Variability of short arm cast application: the influence of experience using fibreglass tape and QuickCast.  

PubMed

A new short arm cast material which is heated to conform to the underlying limb was compared to conventional fibreglass tape. The time required for application, the pressures generated beneath the casts and the availability for digital motion were studied in three groups with varying lengths of casting experience. Results showed that the new immobilizer did not require additional time for application and provided similar interface pressures beneath the casts as compared to fibreglass tape. In addition, metacarpophalangeal joint motion was less restricted with the new casting experience. The shrinkable immobilizer thus offers an alternative to conventional fibreglass tape casts. PMID:9196621

Cohen, M S

1997-01-01

119

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

2010-07-01

120

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

2009-01-01

121

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

Code of Federal Regulations, 2010 CFR

...true Applicability; description of the zinc casting subcategory. 464.40 Section 464.40...EFFLUENT GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Zinc Casting Subcategory § 464.40 Applicability;...

2009-01-01

122

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

123

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

Code of Federal Regulations, 2010 CFR

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

2009-01-01

124

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

Code of Federal Regulations, 2013 CFR

...false Applicability; description of the zinc casting subcategory. 464.40 Section 464.40...AND STANDARDS (CONTINUED) METAL MOLDING AND CASTING POINT SOURCE CATEGORY Zinc Casting Subcategory § 464.40 Applicability;...

2013-07-01

125

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

Code of Federal Regulations, 2013 CFR

... Applicability; description of the aluminum casting subcategory. 464.10 Section 464.10...STANDARDS (CONTINUED) METAL MOLDING AND CASTING POINT SOURCE CATEGORY Aluminum Casting Subcategory § 464.10 Applicability;...

2013-07-01

126

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 464.40...EFFLUENT GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Zinc Casting Subcategory § 464.40 Applicability;...

2010-07-01

127

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

128

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

129

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

Code of Federal Regulations, 2010 CFR

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

2009-01-01

130

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

131

Skin Complications Following Cast Applications: Report of a Case.  

National Technical Information Service (NTIS)

A case of extensive skin atrophy and hyperpigmentation of the right lower leg following eight months of plaster cast application in a boy is described. The differential diagnosis of such lesions are considered and the reported skin complications of castin...

J. G. Beidler

1968-01-01

132

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

133

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

Microsoft Academic Search

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

Nick Cannell; Adrian S. Sabau

2005-01-01

134

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

SciTech Connect

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

J. F. Wallace; D. Schwam

1998-10-01

135

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

136

High Cycle Fatigue Properties of Die-Cast Magnesium Alloy AZ91D with Addition of Different Concentrations of Cerium  

Microsoft Academic Search

The effect of addition of different concentrations of Ce on high-cycle fatigue behavior of die-cast magnesium alloy AZ91D was investigated. Mechanical fatigue tests were conducted at the stress ratio of R = 0.1, and fatigue strength was evaluated using up-and-down loading method. The results show that the grain size of AZ91D alloy is remarkably refined, and the amount of porosity

You Yang; Yongbing Liu; Shuying Qin; Yi Fang

2006-01-01

137

Induction heating process of an Al–Si 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

138

Interface microstructure of aluminum die-casting alloy joints bonded by pulse electric-current bonding process  

Microsoft Academic Search

Aluminum die-casting alloy specimens were bonded by a pulse electric-current bonding (PECB) process using insert alloy powders containing 1mass% Mg into interface between two bonded specimens. Microstructure of the bonded joints was characterized and analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray energy dispersive spectroscopy (EDS). The results proposed that insert alloy powders containing Mg was

Guoqiang Xie; Osamu Ohashi; Kouji Wada; Takayuki Ogawa; Minghui Song; Kazuo Furuya

2006-01-01

139

Microstructure and mechanical properties of ZA104 (0.3–0.6Ca) 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. Dubé

2004-01-01

140

An investigation on the microstructure and tensile properties of direct squeeze cast and gravity die cast 2024 wrought Al alloy  

Microsoft Academic Search

2024 aluminum alloy, conventionally is used for wrought products. If this alloy is subjected to cast process, a large number of shrinkage porosities will be produced within its microstructure due to its long solidification range. Therefore, in order to see the effect of pressure on the microstructure and reduction of shrinkage porosities of this type of alloy, the effect of

E. Hajjari; M. Divandari

2008-01-01

141

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

Code of Federal Regulations, 2013 CFR

...description of the cast iron basis material subcategory. 466.20 Section 466.20 Protection of Environment ENVIRONMENTAL PROTECTION...SOURCE CATEGORY Cast Iron Basis Material Subcategory § 466.20 Applicability; description of the cast iron...

2013-07-01

142

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

Code of Federal Regulations, 2010 CFR

... Applicability; description of the aluminum casting subcategory. 464.10 Section 464.10...GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Aluminum Casting Subcategory § 464.10...

2010-07-01

143

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

Code of Federal Regulations, 2011 CFR

... Applicability; description of the aluminum casting subcategory. 464.10 Section 464.10...GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Aluminum Casting Subcategory § 464.10...

2011-07-01

144

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

Code of Federal Regulations, 2010 CFR

... Applicability; description of the aluminum casting subcategory. 464.10 Section 464.10...GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Aluminum Casting Subcategory § 464.10...

2009-01-01

145

A study on reheating characteristics for thixo die casting process with electromagnetic stirring and extruded aluminum alloys and their mechanical properties  

Microsoft Academic Search

In this paper, the reheating process and mechanical properties of thixo die cast A356 alloy, using electromagnetic stirring\\u000a (EMS) and extrusion before thixo die casting, were discussed. The EMS is used mainly to manufacture raw materials with a globular\\u000a microstructure. If relevant reheating is carried out, products with excellent mechanical properties can be manufactured by\\u000a EMS. Contrarily, extruded material has

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

2009-01-01

146

Determination of the die profile for the investment casting of aerofoil-shaped turbine blades using the finite-element method  

Microsoft Academic Search

Turbine blades and vanes used in aircraft engines are expected to conform to close dimensional tolerances, but super-alloy blade material cannot be machined easily. Although investment casting is an ideal route for producing such net-shape components, it calls for an accurate determination of the casting-die profile. This investigation outlines a simple finite-element methodology (FEM) for obtaining the die profile, which

S. C. Modukuru; N. Ramakrishnan; A. M. Sriramamurthy

1996-01-01

147

Effect of the Amount of Gases on the Foaming Efficiency of Porous Aluminum Using Die Castings Fabricated by Friction Stir Processing  

NASA Astrophysics Data System (ADS)

Porous aluminum was fabricated by friction stir processing using the gases intrinsically contained in aluminum alloy die castings without the use of a blowing agent. The effect of the amount of gases contained in the die castings on the foaming efficiency was investigated. Although the expansion efficiency of each type of gas was not clear, the total amount of gases was sufficient to obtain high porosity. A porosity of approximately 60 pct was obtained with highly spherical and fine pores.

Hangai, Yoshihiko; Kato, Hiroki; Utsunomiya, Takao; Kitahara, Soichiro

2010-08-01

148

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

Microsoft Academic Search

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.

P. W. Hochanadel; G. R. Edwards; M. C. Maguire; M. D. Baldwin

1995-01-01

149

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

Microsoft Academic Search

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

Renji Zhang; Yuan Liu; Da Xu; Yongnian Yan

1998-01-01

150

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

151

Three dimensional non-linear coupled thermo-mechanical FEM analysis of the dimensional accuracy for casting dies in rapid tooling  

Microsoft Academic Search

In Rapid Tooling (RT), all of the forming stages influence the dimensional accuracy of the die. The forming stages include slicing the CAD model to the STL file, making the prototype using an RP machine, obtaining the ceramic mold and transforming the ceramic mold to a metal die. In RT, the precise casting that is to transform the ceramic mold

Yuhua Song; Yongnian Yan; Renji Zhang; Qingping Lu; Da Xu

2001-01-01

152

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

2013-02-01

153

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

154

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

155

25 CFR 301.4 - Application of dies.  

Code of Federal Regulations, 2013 CFR

...2 2013-04-01 2013-04-01 false Application of dies. 301.4 Section 301.4 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER AND TURQUOISE PRODUCTS; STANDARDS §...

2013-04-01

156

Application of particle method to the casting process simulation  

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

157

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

158

The Role of Microstructure on Ductility of Die-Cast AM50 and AM60 Magnesium Alloys  

NASA Astrophysics Data System (ADS)

Die-cast AM50 and AM60 magnesium alloys have been examined to determine the fracture processes in bending and tension and to elucidate the influences of microstructure and porosity distribution on mechanical properties. The effect of section thickness has been explored using 2-, 6-, and 10-mm-thick die-cast plates. The processes of damage accumulation in terms of crack initiation, growth, and linkage leading to eventual failure have been studied qualitatively using progressive tensile straining experiments and three-point bend studies. The presence of a heterogeneous distribution of porosity played a critical role in the observed differences between strains to fracture in tension and in bending. More rapid damage accumulation at lower strains was observed in the high porosity regions with the rate of damage accumulation strongly dependent on the loading mode. Fracture processes at the microstructural level were characterized by scanning electron microscopy using an in-situ bending fixture. Crack initiation and growth occurred predominantly in the interdendritic eutectic regions, both in the presence of porosity and, to a lesser extent, in pore-free regions. The role of porosity volume fraction and distribution on ductility in these alloys has been examined using a modified Brown-Embury model. This model allows the prediction of fracture location in either loading mode by predicting the critical strains for the onset of cracking in differently strained regions of the test samples.

Chadha, Gurjeev; Allison, John E.; Jones, J. Wayne

2007-02-01

159

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

160

The use of friction-stir technology to modify the surfaces of AM60B magnesium die castings  

NASA Astrophysics Data System (ADS)

These experiments were done to evaluate the feasibility of locally modifying the surface properties of magnesium alloys with friction-stir processing. The magnesium alloy used for the study was high-pressure die-cast AM60B, nominally Mg-6Al-0.13 Mn (wt.%). Friction-stir passes were made with a translation speed of 1.7 mm/s using tool-rotation speeds of 1,250 rpm or 2,500 rpm. Stir passes with good appearance were obtained under both conditions. In some cases up to five passes were overlapped on a single bar to produce stir zones with cross-sectional dimensions of about 1.5 mm×10 mm. Metallographic examinations indicated that the stir zones were largely comprised of a magnesium solid solution with equiaxed grains on the order of 5-10 ?m in size. Hardness mapping showed that the stir zones experienced increases of 16-25% compared to the as-cast metal. Room-temperature testing showed that, compared to the cast metal, the stir zones had flow stresses nearly 20% higher with about twice the tensile elongation.

Santella, Michael; Frederick, Alan; Degen, Cassandra; Pan, Tsung-Yu

2006-05-01

161

CHOSEN VALIDATION PROBLEMS IN COMPUTER SIMULATION OF ALUMINUM ALLOY DIE-CASTING SOLIDIFICATION  

Microsoft Academic Search

The possibility of the best prediction of local quality of castings is, at present, one of the most significant criteria testifying about class of used simulation software (so-called Virtual Prototyping systems). In order to the simulation system could perform expectations of the foundry workers, physical-mathematical model of occurring phenomena should contain suitably prepared algorithms (about which the user of systems,

Zenon Ignaszak; Lukasz Bernat; Tomasz Tomczak; Jacek Piasecki

162

Polycyanate die-attach adhesives for microelectronic applications  

Microsoft Academic Search

Polycyanate based die attach adhesives have found increased popularity for many applications including hermetic as well as plastic molded IC packages. Principal advantages of cyanate thermoset are high heat resistance, low outgassing of volatiles, and easily modified to satisfy various application requirements. This paper reviews the development of various types of adhesives designed to meet advanced semiconductor packaging requirements. Generally

My N. Nguyen; Irving Y. Chien; Michael B. Grosse; Michael M. Chau; D. Arthur Burkhart

1995-01-01

163

Tape-cast ceramic membranes for microfiltration application  

Microsoft Academic Search

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 the tape-casting technique. Their pore size could be varied in the range 0.1–0.7 µm and porosity in the range 25%–55% through optimization of experimental parameters. The most important factor which determines the pore size, is the initial

N. Das; S. Bandyopadhyay; D. Chattopadhyay; H. S. Maiti

1996-01-01

164

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, Natércia Carreira; Leal, Mônica Barbosa; Paulino, Silvana Maria; Pagnano, Valéria Oliveira; Bezzon, Osvaldo Luiz

2007-01-01

165

Cathodic chromium carbide coatings for molding die applications  

Microsoft Academic Search

Chromium carbide coating on steel is a good candidate for applications on forming and molding dies. The high mechanical strength, chemical resistance and high temperature stability of Cr3C2 phase can be compatible with the severe abrasive wear and corrosion found in these manufacture operations. Chromium carbide coatings have been deposited on hardened steel probes by cathodic arc evaporation (CAE) from

J. Esteve; J. Romero; M. Gómez; A. Lousa

2004-01-01

166

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

2008-04-15

167

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

168

Adhesive Bonding and Corrosion Protection of a Die Cast Magnesium Automotive Door  

Microsoft Academic Search

It is well known that magnesium alloys, in close proximity to other alloys, are susceptible to galvanic corrosion. Combined with this fact, in automotive applications, it is rare that magnesium will be present in the absence of other alloys such as steel or aluminum. Therefore, in wet applications, where the galvanic cell is completed, it is necessary to isolate the

G. T. Bretz; K. A. Lazarz; D. J. Hill; P. J. Blanchard

169

Influence of Electrolytic Plasma Oxidation Coating on Tensile Behavior of Die-Cast AM50 Alloy Subjected to Salt Corrosion  

NASA Astrophysics Data System (ADS)

Three different thickness ceramic coatings were deposited on die-cast AM50 magnesium alloy in KOH and NaAlO2 solution using electrolytic plasma oxidation (EPO) technology for corrosion prevention. Immersion corrosion tests were carried out in 3.5% NaCl solution for 336 hours to investigate the effect of coating thicknesses on tensile and fracture behaviors of the coated AM50 alloys. The results show that the yield strength (YS) and ultimate tensile strength (UTS) of the coated AM50 alloy subjected to immersion corrosion increase with an increase in coating thicknesses. Further analyses on stress and strain curves indicate that the coating enhances the strain-hardening rates of the corroded alloy during its plastic deformation. SEM examination on the fractured surface manifests that the substrate AM50 alloys exhibit characteristics of ductile deformation with deep dimples. However, brittle features prevail on the fractured surface of the mixed layer of coating plus oxidation corrosion product. Micro cracks were observed between the mixed layer and the AM50 alloy substrate induced by corrosion and within the mixed layer induced by EPO process, which could be responsible for the brittle fracture.

Han, Lihong; Nie, Xueyuan; Zhang, Peng; Zhang, Qiang; Hu, Henry

170

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

SciTech Connect

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

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

1993-08-01

171

Fatigue characterization of high pressure die-cast magnesium AM60B alloy using experimental and computational investigations  

NASA Astrophysics Data System (ADS)

The object of the current dissertation is to foster fundamental advances in microstructure-fatigue characteristics of a high pressure die cast magnesium AM60B alloy. First, high cycle fatigue staircase experiments were conducted on specimens extracted from automobile instrument panels. The resulting fracture surfaces were then examined with scanning electron microscopic imaging to elucidate the fatigue crack initiation sites and propagation paths at different stages of the fatigue life. Due to the fact that the qualification of the crack initiation and propagation mechanisms through experiment alone is difficult, complementary micromechanical finite element simulations were conducted. Particularly, the effects of different applied loading conditions and the porosity morphology (e.g. pore shape, pore size, pore spacing, proximity to the free surface) on the maximum plastic shear strain range, as a driving force for crack initiation, were analyzed. Moreover, at the microstructually small crack (MSC) propagation stage, the shielding effects of beta-phase Mg17Al12 particles were systematically studied. Based on the distribution of the maximum principal stress within the particles and the maximum hydrostatic stress along the particle/matrix interfaces, the relative influence of the pre-damaged (fractured or debonded) particles and various particle cluster morphologies were carefully investigated. In the finite element simulations, the constitutive behaviours of AM60B alloy and the alpha-matrix were simulated by the advanced kinematic hardening law tuned with experimentally determined material parameters under cyclic loading.

Lu, You

172

X-Ray CT Inspection for Porosities and Its Effect on Fatigue of Die Cast Aluminium Alloy  

NASA Astrophysics Data System (ADS)

Effect of porosities on the fatigue properties of high-pressure die cast aluminium alloy is addressed. Three-dimensional shape and location of porosities in the specimen were inspected by the X-ray CT to determine which pore affects the fatigue crack. The tension-compression fatigue test was carried out and the CT inspection was also conducted for all the specimens before and after the fatigue test. By comparing the CT inspection with the SEM observation of the fracture surface, we confirmed that the crack initiation was restricted to shrinkage pores near the specimen surface, and the inner large pores were not the source of fatigue crack. But we found that a cluster of shrinkage cavities can initiate a crack and affect the fatigue fracture although it exists far inside. Multiple cracks were also found on the bumpy fracture surface, and they seemed to reduce the fatigue life by coalescing into a single large crack. Moreover, we demonstrated the successive CT inspection during the fatigue test, and showed its availability to detect the fatigue crack propagation behavior.

Kuwazuru, Osamu; Murata, Yozo; Hangai, Yoshihiko; Utsunomiya, Takao; Kitahara, Soichiro; Yoshikawa, Nobuhiro

173

Pressurized solidification of semi-solid aluminum die casting alloy A356  

Microsoft Academic Search

Pressurized solidification behavior of semi-solid aluminum alloy A356 slurry in relation to the final microstructures and mechanical properties has been investigated. Sound semi-solid slurry has been produced, in which the primary ?-Al presented in average diameter of 65?m and shape factor of 0.84, and featured zero-entrapped eutectic. The structural investigation revealed that application of pressure during solidification of semi-solid slurry

Hong-Min Guo; Xiang-Jie Yang; Jia-Xuan Wang

2009-01-01

174

Effect of Ce on microstructure, mechanical properties and corrosion behavior of high-pressure die-cast Mg–4Al-based alloy  

Microsoft Academic Search

Mg–4Al–xCe–0.3Mn (x=0, 1, 2, 4 and 6wt.%) alloys were prepared by high-pressure die-casting. The microstructures, mechanical properties and corrosion behavior were investigated. The cross-section of test bar is divided into the fine skin region and the relatively coarse interior region by a narrow band. The dendritic arm spacing is greatly reduced and the secondary phases Al11Ce3 and (Al, Mg)2Ce with

Jinghuai Zhang; Zhe Leng; Milin Zhang; Jian Meng; Ruizhi Wu

2011-01-01

175

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

Microsoft Academic Search

Optimum heat treatment of dies (quenching) is critical in ensuring satisfactory service performance: rapid cooling rates increase the thermal fatigue\\/heat checking resistance of the steel, although very fast cooling rates can also lead to distortion and lower fracture toughness, increasing the danger of catastrophic fracture. Goal of this project is to increase die life by using fast enough quenching rates

J. F. Wallace; D. Schwam

1995-01-01

176

Modified tape casting method for ceramic joining; Application to joining of silicon carbide  

Microsoft Academic Search

A simple modified tape casting procedure has been developed for application to ceramic joining when the joining materials are in powder form. The method involves preparation of a slurry from the powder, solvent, and thermoplastic binder, and then casting directly onto the joining surface using a moving doctor blade. Handling of the tape prior to joining is not necessary: therefore,

Barry H. Rabin

1990-01-01

177

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

178

Subclavian vein thrombosis after application of body cast.  

PubMed

Mehta-Cotrel body casting is a well-recognized and effective technique for the treatment of progressive infantile scoliosis. The treatment can be challenging to execute given the commitment required by the patient's family and treatment team, and is not without complications. In this report, we detail the occurrence of a subclavian vein thrombosis after the placement of a Mehta-Cotrel cast for the treatment of progressive infantile kyphoscoliosis. To date, this is a previously unreported complication after body casting. Expeditious and accurate diagnosis of this complication leads to effective treatment without further morbidity. Therefore, clinicians using body casting for the treatment of scoliosis should be aware of the possibility of this complication and know how to quickly diagnose and treat it. PMID:23232388

Badlani, Neil; Korenblit, Allen; Hammerberg, Kim

2013-01-01

179

Cost Saving Through Application of the Investment Casting Process.  

National Technical Information Service (NTIS)

Four XB231A Mechanical Assembly metal components (three only machined, and one which is machined and welded) were replaced with four investment castings, thereby realizing considerable cost saving. The XB231A Mechanical Assembly originally required mechan...

W. E. Cromwell J. P. Paul G. L. Tiehen

1976-01-01

180

The application of quality criteria for the prediction of porosity in the design of casting processes  

SciTech Connect

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-aided design and analysis of casting processes. The quality criteria applicable to a particular casting process are dependent on the thermal conditions and the solidification mode of the alloy. Accordingly, casting processes and alloy types are divided into four groups according to whether porosity distribution is dominated by liquid transport, dendrite structure, or bubble pressure, and a different set of quality criteria is obtained for each group. Results from test castings of Al-4.5% Cu alloy cast in a variety of configurations and mold media are used to develop models and extract quality criteria. The results obtained on Al-4.5% Cu alloy are tested on data on Al-7% Si-0.3% Mg alloy castings reported in the literature. The results show that the quality criteria developed for USSR Cu alloy are also applicable to other alloy systems. The procedure for applying quality criteria for the prediction of microporosity distributions in commercial casting processes is outlined.

Viswanathan, S.; Sikka, V.K. (Oak Ridge National Lab., TN (United States)); Brody, H.D. (Connecticut Univ., Storrs, CT (United States). School of Engineering)

1993-01-01

181

The application of quality criteria for the prediction of porosity in the design of casting processes  

SciTech Connect

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-aided design and analysis of casting processes. The quality criteria applicable to a particular casting process are dependent on the thermal conditions and the solidification mode of the alloy. Accordingly, casting processes and alloy types are divided into four groups according to whether porosity distribution is dominated by liquid transport, dendrite structure, or bubble pressure, and a different set of quality criteria is obtained for each group. Results from test castings of Al-4.5% Cu alloy cast in a variety of configurations and mold media are used to develop models and extract quality criteria. The results obtained on Al-4.5% Cu alloy are tested on data on Al-7% Si-0.3% Mg alloy castings reported in the literature. The results show that the quality criteria developed for USSR Cu alloy are also applicable to other alloy systems. The procedure for applying quality criteria for the prediction of microporosity distributions in commercial casting processes is outlined.

Viswanathan, S.; Sikka, V.K. [Oak Ridge National Lab., TN (United States); Brody, H.D. [Connecticut Univ., Storrs, CT (United States). School of Engineering

1993-12-31

182

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

SciTech Connect

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

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

1995-03-01

183

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

184

Application in casting defect lossless examination based on surf  

NASA Astrophysics Data System (ADS)

Based on the study of measures of the algorithm casting defect lossless examination and characteristics of X-ray imaging, a new automatic detection based on SURF is presented. Firstly, the algorithm detects the interested points of specifically component model in the standard image samples by SURF. Then the interested points of inspection produce are detected when the rotary worktable makes one revolution, at the same time, the interested points between model and produce are matched. The number of matched points is the basis for whether the product contains the component. Experimental results show that this method is effective in determining the component model well or not, which provides a novel method for casting defect lossless examination.

Fan, Youchen; Sun, Huayan; Wang, Haoxiang

2013-08-01

185

Virtual aluminum castings: An industrial application of ICME  

Microsoft Academic Search

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

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

2006-01-01

186

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

187

Virtual aluminum castings: An industrial application of ICME  

NASA Astrophysics Data System (ADS)

The automotive product design and manufacturing community is continually besieged by Hercule an engineering, timing, and cost challenges. Nowhere is this more evident than in the development of designs and manufacturing processes for cast aluminum engine blocks and cylinder heads. Increasing engine performance requirements coupled with stringent weight and packaging constraints are pushing aluminum alloys to the limits of their capabilities. To provide high-quality blocks and heads at the lowest possible cost, manufacturing process engineers are required to find increasingly innovative ways to cast and heat treat components. Additionally, to remain competitive, products and manufacturing methods must be developed and implemented in record time. To bridge the gaps between program needs and engineering reality, the use of robust computational models in up-front analysis will take on an increasingly important role. This article describes just such a computational approach, the Virtual Aluminum Castings methodology, which was developed and implemented at Ford Motor Company and demonstrates the feasibility and benefits of integrated computational materials engineering.

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

2006-11-01

188

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.

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

2013-01-01

189

Influence of chemical composition and microstructure on thermal conductivity of alloyed pearlitic flake graphite cast irons  

Microsoft Academic Search

Thermal conductivity is one of the most important properties of flake graphite cast iron, that decides the transient temperature and thermal stress distribution in the components which are subjected to elevated temperature applications. Such applications include cylinder heads, brake-drums, exhaust manifolds, ingot moulds, hot mill rolls and dies. Thermal conductivity values are experimentally measured in 23 flake graphite cast irons

Mohan C. Rukadikar; G. P. Reddy

1986-01-01

190

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

Code of Federal Regulations, 2013 CFR

38 Pensions, Bonuses, and Veterans' Relief 1 2013-07-01 2013-07-01 false Veteran dies without having filed application for...Section 11.128 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS...

2013-07-01

191

Modified tape casting method for ceramic joining; Application to joining of silicon carbide  

SciTech Connect

A simple modified tape casting procedure has been developed for application to ceramic joining when the joining materials are in powder form. The method involves preparation of a slurry from the powder, solvent, and thermoplastic binder, and then casting directly onto the joining surface using a moving doctor blade. Handling of the tape prior to joining is not necessary: therefore, binder content is minimized, plasticizers are not required, and viscosity is controlled by solvent content. The utility of this technique for producing joints with thin, uniform interlayers is demonstrated for silicon carbide materials joined with TiC + Ni and SiC + Si.

Rabin, B.H. (Idaho National Engineering Lab., EG and G Idaho, Inc., Idaho Falls, ID (US))

1990-09-01

192

A compact flip chip single die WiFi FEM for smart phone application  

Microsoft Academic Search

A flip chip single die WiFi FEM is developed using Bi-FET (HBT+E\\/D-PHEMT) technology for smart phone application. High thermal conductive copper-pillar bumps were developed for the flip chip process. This FEM flip chip die consists of a high-pass filter (HPF), a 2 GHz WiFi PA with on-chip regulator, PAON logic and detector circuit, and an SP3T. It showed good over-voltage

Cindy Yuen; Kirk Laursen; Duc Chu; Yi-Ching Pao; Alexander Chernyakov; Patric Heide

2010-01-01

193

Titanium Castings Today.  

National Technical Information Service (NTIS)

Titanium castings weighing from a few grams to over half a ton are being produced. Three foundries produce castings in rammed graphite molds chiefly for applications where high resistance to corrosion is important. Three other foundries use investment mol...

J. G. Kura

1973-01-01

194

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

195

Fabrication of fiber reinforced metal matrix composites by squeeze casting technology  

Microsoft Academic Search

Squeeze forming process is a special casting technique that combines the advantages of traditional high pressure die casting, gravity permanent mold die casting and common forging technology. It is a relatively new casting process. It is otherwise called squeeze forming, liquid forging, liquid pressing, extrusion casting, liquid metal stamping, pressure crystallization and corthias casting. The above said process was first

T. R. Vijayaram; S. Sulaiman; A. M. S. Hamouda; M. H. M. Ahmad

2006-01-01

196

Measurement of die stress in advanced electronic packaging for space and terrestrial applications  

NASA Astrophysics Data System (ADS)

Mechanical stresses in advanced electronic packages for space and terrestrial applications can cause premature failures due to such causes as fracture of the die, severing of connections, die bond failure, solder fatigue, and encapsulant cracking. These stresses are often thermally-induced, and result from uneven expansions and contractions of the various assembly materials due to mismatches in the coefficients of thermal expansion (CTE's). In this work, special (111) silicon test chips containing an array of piezoresistive stress sensor rosettes have been applied within several plastic encapsulated electronic packaging configurations. The test chips contain optimized eight element dual polarity rosettes which are capable of evaluating the complete stress state (6 stress components) at points on the surface of the die. Calibrated and characterized test chips were packaged in chip-on-board configurations using ``glob-top'' liquid encapsulants. The post packaging room temperature resistances of the sensors were then recorded. Using the measured resistance changes and appropriate theoretical equations, the stresses in the die have been calculated. Also, three-dimensional nonlinear finite element simulations of the chip-on-board packages were performed. The experimental results were in good agreement with the finite element predictions.

Suhling, J. C.; Lin, S. T.; Moral, R. J.; Johnson, R. W.; Jaeger, R. C.

1997-01-01

197

Worldline casting of the stochastic vacuum model and nonperturbative properties of QCD: General formalism and applications  

SciTech Connect

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 nonperturbative features of the model are studied. In particular, contributions associated with the spin-field interaction are calculated, and the validity of both the loop equations and of the Bianchi identity is 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 an 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 fluctuations of the Wilson loop contour is also estimated.

Karanikas, A. I.; Ktorides, C. N. [University of Athens, Physics Department, Nuclear and Particle Physics Section, Panepistimiopolis, Ilissia GR 15771, Athens (Greece)

2009-03-15

198

Die compaction simulation: Simplifying the application of a complex constitutive model using numerical and physical experiments  

NASA Astrophysics Data System (ADS)

The die compaction process is a rapid net-shape manufacturing process that yields low strength parts which are then sintered to create a functional part. The sintering stage induces shrinkage inversely proportional to the density of the part and distortion if density gradients are present. For an accurate description of the final shape and size, the amount of shrinkage and distortion must be anticipated and incorporated into the original tool design. Numerical modeling tools can be used to develop protocols to attain desired compact properties. The die compaction process is a complex process as the material undergoes particle rearrangement followed by plastic deformation. Modeling the process requires the use of a complex material model. The modified Drucker-Prager "cap" model can describe the loose powder response and the particle deformation under compaction loads. This research looks at simplifying the application of a numerical finite element model defined using this complex model. The significance of the parameters that define the material model on the results has been determined using a robust sensitivity analysis technique. The results from the analysis have been used to identify the critical parameters for density predictions. Since the recommended testing procedures used to characterize the material parameters are expensive and difficult to perform, alternative testing methods have been investigated for ease in industrial application. A testing protocol using a test method proposed by Coube and Riedel (2000) and a technique proposed in this research has been developed for characterizing the material parameters for the "cap" model. The protocol has been applied for characterizing two commonly used metal powders for die compaction applications: a water atomized A1000C iron powder and a water atomized 316L stainless steel powder. A numerical finite element model with the characterized parameters has been verified for application to predict density gradients in a die compacted part by comparing the numerically predicted density distribution to the density field obtained from physical measurements. The results of the verification establishes a good predictive capability of the numerical model and the testing protocol developed in this research.

Wagle, Gautam S.

199

Application of tape-cast graded impedance impactors for light-gas gun experiments  

Microsoft Academic Search

Fabrication of compositionally graded structures for use as light-gas gun impactors has been demonstrated using a tape casting technique. Mixtures of metal powders in the Mg-Cu system were cast into a series of 19 tapes with uniform compositions ranging from 100% Mg to 100% Cu. The individual compositions were fabricated into monolithic pellets for characterization of microstructure, density, and sound

L. Peter Martin; J. Reed Patterson; Daniel Orlikowski; Jeffrey H. Nguyen

2007-01-01

200

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

201

Application of baby deck initiation to reduce coal damage during cast blasting  

Microsoft Academic Search

The extra explosive energy used in cast blasting reduces the amount of overburden to be handled by the machinery but increases the risk of damage to the underlying coal. This damage will lead to reduced coal recovery and may negate much of the benefit sought from cast blasting. The Julius Kruttschnitt Mineral Research Centre in close association with the Australian

Sarma S. Kanchibotla; Andrew Scott

2000-01-01

202

Reduction in the development lead times of complex investment castings by the application of CIM technology  

Microsoft Academic Search

The development costs associated with complex investment casting processes for components, such as turbine blades, are large\\u000a due to long lead times. A CIM system is described which has been developed, in collaboration with Rolls-Royce, to substantially\\u000a reduce lead times in the development of precision cast turbine blades.

N. J. Brookes; C. B. Besant

1988-01-01

203

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, Grégory

2012-07-01

204

Design and application of dynamic control system for secondary cooling of billet continuous casting  

Microsoft Academic Search

The continuous casting process is used for the solidification of molten steel into semi-finished shapes. The technology of secondary cooling is extremely important for output of the casting machine and quality of the strand. In the paper, a dynamic control system is presented, including solidification model in the secondary cooling, feedforward control based on continuous temperature measurement in tundish and

Wenhong Liu; Zhi Xie

2010-01-01

205

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

NASA Astrophysics Data System (ADS)

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 oxide films which are subsequently trapped into the liquid and generate micro cracks and casting defects. In this paper a new CRIMSON process is introduced which features instead of gravity filling method, using the single shot up-casting method to realize the rapid melting and rapid filling mould operations which reduce the contact time between the melt and environment thus reducing the possibility of defect generation. Another advantage of the new process is the drastic reduction of energy consumption due to shortened melting and filling time. Two types of casting samples from SCP and ICP were compared with the new process. The commercial software was used to simulate the filling and solidification processes of the casting samples. The results show that the new process has a more improved behaviour during filling a mould and solidification than the two conventional casting processes.

Dai, X.; Jolly, M.; Zeng, B.

2012-07-01

206

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

NASA Astrophysics Data System (ADS)

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

Das, Nandini; Maiti, H. S.

2009-11-01

207

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

208

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 SOURCE CATEGORY Continuous...resulting from the continous casting of molten steel into intermediate or semi-finished steel products through water cooled...

2010-07-01

209

Application of Anand's constitutive model on twin roll casting process of AZ31 magnesium alloy  

Microsoft Academic Search

Twin-roll thin strip casting process combines casting and hot rolling into a single process, in which thermal stress and thermal mechanical stress were involved. Considering the high temperature gradient, the existing of liquid and solid regions and rolling deformation, suitable constitutive model is the key to describe the process. Anand's model is a temperature-dependent, rate-dependent and unified of creep and

Xiao-dong HU; Dong-ying JU

2006-01-01

210

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

211

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

212

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

PubMed

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

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

1990-07-01

213

Clinical experience with a new casting tape.  

PubMed

Between October 1977 and 1978, 93 CutterCast casts were applied at the Veterans Administration Hospital in Atlanta, Georgia. The composition and application of this new casting system are described, and the performance of the 93 casts is evaluated in relation to ease of application, roentgenographic clarity, skin condition, patient comfort, and ease of removal. The advantages and disadvantages are discussed. PMID:7375970

Fleming, L L; Miller, K; Sinback, M

1980-05-01

214

Modeling and control of casting and welding processes  

SciTech Connect

This book contains papers divided among the following sections: process monitor and control in welding; plasma processing and refining; strip casting; modelling of welding processes; CAD/CAM in casting; investment and die casting; ingot, continuous and other shape casting; and rapid solidification and microstructural evolution.

Kou, S.; Mehrabian, R.

1986-01-01

215

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

216

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

National Technical Information Service (NTIS)

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...

2005-01-01

217

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

National Technical Information Service (NTIS)

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...

A. S. Sabau

2005-01-01

218

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

219

Application of numerical simulation for wear analysis of warm forging die  

Microsoft Academic Search

Warm forging process has better forming precision than hot forging process and has better formability than cold forging. But warm forging die sustains higher temperature and working pressure, the die wear is faster than those of hot forging and cold forging. The purpose of this research is to combine the experimental techniques, wear model and numerical simulation method to predict

R. S Lee; J. L Jou

2003-01-01

220

Validating CSCW strategies and applications for rapid product development in the investment casting process  

Microsoft Academic Search

The aim of this study is to apply and validate a general-purpose working methodology, derived from the analysis of processes which come from two different domains (the field of medicine and the preservation of cultural heritage), in the investment casting process. CSCW methods and tools have proven to be the best ‘gluing tool’ to bond the different activities, and thus

C. Bandera; S. Filippi; B. Motyl

2006-01-01

221

The meaning of high stress abrasion and its application in white cast irons  

Microsoft Academic Search

White cast irons perform much less favourably in industrial service environments such as ball mills than would be predicted by standard laboratory abrasion tests. Pin abrasive tests are widely thought to simulate high stress abrasion, but in reality they grossly over-estimate service lives of white iron mill liners compared to pearlitic steel liners. The ‘impact-abrasion’ hypothesis has suggested that the

J. D. Gates; G. J. Gore; M. J. P. Hermand; M. J. P. Guerineau; P. B. Martin; J. Saad

2007-01-01

222

Simulation of solidification paths in high chromium white cast irons for wear applications  

Microsoft Academic Search

Thermodynamic calculations of the solidification paths in the Fe-Si-Cr-C system using the CALPHAD approach have been used for the interpretation of the solidification microstructures of high chromium white cast irons containing high silicon contents. The results show a reasonable agreement between experiments and calculations for alloys up to 2 wt% Si. The results suggests that the stability of the cementite

Cláudio Geraldo Schön; Amilton Sinatora

1998-01-01

223

Rapid prototyping and tooling techniques: a review of applications for rapid investment casting  

Microsoft Academic Search

Investment casting (IC) has benefited numerous industries as an economical means for mass producing quality near net shape metal parts with high geometric complexity and acceptable tolerances. The economic benefits of IC are limited to mass production. The high costs and long lead-time associated with the development of hard tooling for wax pattern moulding renders IC uneconomical for low-volume production.

C. M. Cheah; C. K. Chua; C. W. Lee; C. Feng; K. Totong

2005-01-01

224

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...

225

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...

226

Development of a compact nuclear microprobe system and its application to the analysis of titanium castings  

NASA Astrophysics Data System (ADS)

A compact nuclear microprobe system with a new configuration and a number of analysis functions has been developed. The overall size of the system is 4.5 (length) × 2.5 (width) × 1.8 (height) m. To estimate the focusing performance, secondary electron microscopic (SEM) images of line and 2-dimensional patterns of Au on a Si substrate were obtained. Stripes of 0.75 and 1 ?m were resolved in horizontal and vertical directions, respectively. Micro-PIXE has been applied to the analysis of Ti castings. Two kinds of casting samples were prepared. They were cast by using a phosphate bonded or an ethylsilicate bonded investment. It was found that Si and P in the former casting diffuse down to at least 160 and 80 ?m under the surface and Si in the latter down to at least 40 ?m. It was also found that these values of diffusion depths are in good correlation with the results of a micro-Vicker's hardness test.

Ishibashi, K.; Inoue, K.; Yokoyama, K.; Kawata, Y.; Fukuyama, H.; Iwasaki, M.

1993-04-01

227

Electroslag Casting.  

National Technical Information Service (NTIS)

The report contains an examination of the most important characteristics of the physico-mechanical properties of electroslag cast metal in comparison with the properties of open hearth steel, subjected to deformation by forging or used in the cast form.

B. E. Paton B. I. Medovar G. A. Boiko

1975-01-01

228

Application of the Carreau model to tape-casting fluid mechanics  

SciTech Connect

Tape-casting experiments were conducted with 30 different aqueous suspensions whose viscosities were functions of strain rate. Tape thickness measurements of the resulting casts varied from 180 to 310 {micro}m. The three-parameter Carreau model accurately conformed to the rheological data of the suspensions between 0.46 and 581 s{sup {minus}1}. With this model, the zero-shear-rate viscosities of the various suspensions ranged from 20 to 2 {times} 10{sup 5} mPa {center_dot} s. Within the framework of the Carreau model, the equations of motion for the flow of the suspension through the doctor blade were solved numerically. Calculated thicknesses were in very good agreement with experimental measurements.

Terrones, G.; Smith, P.A.; Armstrong, T.R.; Soltesz, T.J. [Pacific Northwest National Lab., Richland, WA (United States)

1997-12-01

229

Attitudes of elderly Korean patients toward death and dying: an application of Q-methodology  

Microsoft Academic Search

The aim of this study was to identify the attitudes of elderly Korean patients toward death and dying using Q-methodology to aid in the development of basic strategies for nursing care of elderly Koreans. Thirty participants at a university hospital sorted 40 selected Q-statements on a nine-point scale. Data analysis identified three types of attitudes toward death and dying in

Eunja Yeun

2005-01-01

230

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

Microsoft Academic Search

As part of a multi-year program funded by the United States Nuclear Regulatory Commission (US NRC) to address nondestructive examination (NDE) reliability of inservice inspection (ISI) programs, studies conducted at the Pacific N¬orthwest National Laboratory (PNNL) in Richland, Washington, have focused on assessing novel NDE approaches for the inspection of coarse-grained, cast stainless steel reactor components. The primary objective of

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

2006-01-01

231

Scuffing of cast iron and Al390-T6 materials used in compressor applications  

Microsoft Academic Search

Scuffing can lead to catastrophic failure in engineering components, but the surface mechanism that leads to scuffing is not well understood. In this experimental study, the surface and subsurface changes on gray cast iron and Al390-T6 were investigated under starved lubrication (a mixture of R410A refrigerant combined with a polyolester lubricant) and pure sliding. Controlled tribological experiments were conducted using

Allison Y. Suh; Jayesh J. Patel; Andreas A. Polycarpou; Thomas F. Conry

2006-01-01

232

A model for macrosegregation and its application to Al-Cu castings  

Microsoft Academic Search

A macrosegregation model has been developed to evaluate solute redistribution during solidification of casting alloys. The\\u000a continuum formulations were used to describe the macroscopic transports of mass, energy, and momentum, associated with the\\u000a microscopic transport phenomena, for two-phase systems. It was assumed that liquid flow is driven by thermal and solutal buoyancy,\\u000a as well as by solidification contraction. The movement

S. Chang; D. M. Stefanescu

1996-01-01

233

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

SciTech Connect

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

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

2006-10-01

234

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

NASA Astrophysics Data System (ADS)

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

Elalem, Kaled

235

Attitudes of elderly Korean patients toward death and dying: an application of Q-methodology.  

PubMed

The aim of this study was to identify the attitudes of elderly Korean patients toward death and dying using Q-methodology to aid in the development of basic strategies for nursing care of elderly Koreans. Thirty participants at a university hospital sorted 40 selected Q-statements on a nine-point scale. Data analysis identified three types of attitudes toward death and dying in elderly patients in Korea: religion-dependent, science-adherent, and sardonic. Religion-dependent elders are highly dependent upon religion as evidenced by their reply that they would like to rely on God and a minister the most. Science-adherent elders have great affection for life and believe in modern medical advancements. The sardonic elders regard death as the dispensation of nature so there is no need to be afraid of death and dying. This study will contribute to the understanding that nurses and other health professionals have of the perceptions of elderly Koreans about death and dying. Also, the findings may provide the basis for the development of more appropriate strategies to improve death and dying education programs of health professionals. PMID:16210025

Yeun, Eunja

2005-11-01

236

Die Klavierspielerin  

Microsoft Academic Search

Die Klavierlehrerin Erika Kohut (in der Folge als „Erika“ bezeichnet), Alter Ende dreißig, kommt abends — offensichtlich später\\u000a als gewohnt — nach Hause in die Wohnung, die sie mit ihrer Mutter teilt. Diese stellt sie wegen des Spätkommens zur Rede.\\u000a Die Begründung der Tochter, sie sei spazieren gegangen, als Ausrede erlebend, entreißt die Mutter ihr die Handtasche durchsucht\\u000a diese, findet

Marianne Springer-Kremser; Peter Schuster

237

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

238

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

239

A model for macrosegregation and its application to Al-Cu castings  

SciTech Connect

A macrosegregation model has been developed to evaluate solute redistribution during solidification of casting alloys. The continuum formulations were used to describe the macroscopic transports of mass, energy, and momentum, associated with the microscopic transport phenomena, for two-phase systems. It was assumed that liquid flow is driven by thermal and solutal buoyancy, as well as by solidification contraction. The movement of free surface was also considered to ensure volume conservation. In numerical calculations, the solidification event was divided into two stages. In the first stage, the liquid containing freely moving equiaxed grains was described through the relative viscosity concept. In the second stage, when a fixed dendritic network formed after dendrite coherency, the mushy zone was treated as a porous medium. After validation of the proposed model for the case of segregation in a bottom-chilled unidirectionally solidified casting of Al-Cu alloys, the numerical model was applied to the study of three different castings with simple geometry. It was found that solutal convection tends to decrease the macrosegregation generated by thermal convection. When shrinkage-driven convection was also considered, segregation was again increased, with highly segregated areas forming away from the riser and next to the mold wall. It was demonstrated that solidification contraction has a stronger effect on the liquid flow in the mushy region than buoyancy. The model also was applied to assess the probability of pore formation based on the pressure drop concept. While in the absence of experimental data for the critical pressure drop it was not possible to uniquely predict the formation of porosity, it was possible to indicate the regions where porosity may form preferentially.

Chang, S.; Stefanescu, D.M. [Univ. of Alabama, Tuscaloosa, AL (United States). Dept. of Metallurgical and Materials Engineering

1996-09-01

240

Microstructure and Corrosion Characterization of Squeeze Cast AM50 Magnesium Alloys  

NASA Astrophysics Data System (ADS)

Squeeze casting of magnesium alloys potentially can be used in lightweight chassis components such as control arms and knuckles. This study documents the microstructural analysis and corrosion behavior of AM50 alloys squeeze cast at different pressures between 40 and 120 MPa and compares them with high-pressure die cast (HPDC) AM50 alloy castings and an AM50 squeeze cast prototype control arm. Although the corrosion rates of the squeeze cast samples are slightly higher than those observed for the HPDC AM50 alloy, the former does produce virtually porosity-free castings that are required for structural applications like control arms and wheels. This outcome is extremely encouraging as it provides an opportunity for additional alloy and process development by squeeze casting that has remained relatively unexplored for magnesium alloys compared with aluminum. Among the microstructural parameters analyzed, it seems that the ?-phase interfacial area, indicating a greater degree of ? network, leads to a lower corrosion rate. Weight loss was the better method for determining corrosion behavior in these alloys that contain a large fraction of second phase, which can cause perturbations to an overall uniform surface corrosion behavior.

Sachdeva, Deepika; Tiwari, Shashank; Sundarraj, Suresh; Luo, Alan A.

2010-12-01

241

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 Cervera, Pascual; Aracil, Rafael

1994-11-01

242

Application of tape-cast graded impedance impactors for light-gas gun experiments  

NASA Astrophysics Data System (ADS)

Fabrication of compositionally graded structures for use as light-gas gun impactors has been demonstrated using a tape casting technique. Mixtures of metal powders in the Mg-Cu system were cast into a series of 19 tapes with uniform compositions ranging from 100% Mg to 100% Cu. The individual compositions were fabricated into monolithic pellets for characterization of microstructure, density, and sound wave velocity. Graded impactors were fabricated by stacking layers of different compositions in a sequence calculated to yield a tailored acoustic impedance profile, and were characterized by ultrasonic C-scan and white light interferometry. The graded impactors were launched into stationary Al targets using a two-stage light-gas gun, and the resulting wave profiles were measured with either VISAR or Photonic Doppler Velocimetry. For an impactor using only seven compositions ranging from Mg to Cu, the composition steps are visible in the wave profiles. An impactor utilizing the full series of 19 compositions produces smoother compression with no visible manifestation of the discrete-layer structure. Hydrodynamic simulations of these impactors also suggest smooth compression profiles within the impactor.

Martin, L. Peter; Patterson, J. Reed; Orlikowski, Daniel; Nguyen, Jeffrey H.

2007-07-01

243

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.; Sjöström, Ulf; Jonsson, Thomas; Lee, Peter D.; Mills, Kenneth C.; Petäjäjärvi, Marko; Pirinen, Jarno

2012-07-01

244

Melting and casting of FeAl-based cast alloy  

Microsoft Academic Search

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

V. K. Sikka; D. Wilkening; J. Liebetrau; B. Mackey

1998-01-01

245

The application of integrated computational material engineering (ICME) in metal castings simulation  

NASA Astrophysics Data System (ADS)

Integrated Computational Materials Engineering (ICME) is emerging as a methodology for developing advanced materials, manufacturing processing, and engineering components in a faster and more cost effective way. For casting processes, ICME involves many physical phenomena such as thermodynamics, heat transfer, fluid flow, stress, defect formation, microstructure evaluation, and thermophysical and mechanical properties. In this paper, the integration of thermodynamic calculations, thermophysical and mechanical property predictions, and the prediction of microstructure and defects during solidification and heat treatment will be presented. Such integration is helpful to understand the effects of alloy chemistry and processing conditions, and their relationship to microstructure, defect formation, and the final mechanical properties from solidification to heat treatment. Eventually the alloy chemistry and processing parameters can be optimized with the help of the integrated computational modelling.

Guo, Jianzheng; Cao, Weisheng; Samonds, Mark

2012-07-01

246

Die CSU  

Microsoft Academic Search

Die bayerischen Landtagswahlen vom 28. September 2008 bedeuteten eine tiefe Zäsur für die erfolgsverwöhnte christlich-soziale\\u000a Regierungspartei Bayerns. Vom „Ende der Staatspartei“, dem „Verlust der Einzigartigkeit Bayerns“, sogar von einer „Revolution“\\u000a im süddeutschen Freistaat war in der Presse die Rede. Schließlich hatte die CSU mehr als vierzig Jahre lang die bayerische\\u000a Staatsregierung gestellt, ohne dabei auf einen Koalitionspartner angewiesen zu sein.

Stephan Klecha; Clemens Wirries

247

Investment casting  

SciTech Connect

Materials and manufacturing technologies for investment casting have made impressive gains over the past several years, resulting in higher productivity, shorter lead times, and superior castings. To improve efficiency, investment casters have applied total quality control methods, new management concepts, and computer controls. Management and production efficiency improvements have been critical factors in maintaining and expanding market share.

Bidwell, H.T. [Investment Casting Inst., Dallas, TX (United States)

1996-04-01

248

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

249

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

250

Thermal investigation of compound cast steel tools  

NASA Astrophysics Data System (ADS)

Tools for hot forging are exposed to complex stresses during their life-cycle. Therefore, forging dies should have a high wear resistance and toughness on the surface, combined with excellent thermal conductivity in the die body. Hot-work tool steel is appropriate for this application except from its thermal conductance. Hence, a tool consisting of hot-work tool steel in the area of contact and heat-treatable steel as die body is favorable. A smoothly graded microstructure in the joint zone between the two steel alloys is needed to match with the requirements. Fabrication of such functionally graded dies by sand casting exhibits high sensitivity to temperature and geometry dependent parameters. To melt on the inlay's surface must be ensured without destroying this region according to overheat coarsening and mixing of alloying elements. Instead of empirical methods to optimize the process parameters, a thermographic CCD-device is used for visualization of the heat flow while pouring the melt on the inlay. In fact the molten metal flow can be directed homogeneously across the bonding surface at adequate temperatures after evaluation of thermography data. The use of a silica-aerogel sheet as opaque window beneath the inlay in the mold enables systematic development of gating and risering, whereas undesirable scaling of the inlay due to the change of emissivity is retarded. Infrared image sequences clearly demonstrate the influence of different ring gating systems concerning the filling properties. Non-joined cavities may even be classified from image data. Compound cast steel tools have been manufactured and examined in forging trials validating life-cycle prolongation.

Schaper, Mirko; Haferkamp, Heinz; Niemeyer, Matthias; Pelz, Christoph; Viets, Roman

1999-03-01

251

Application of the cost-per-good-die metric for process design co-optimization  

NASA Astrophysics Data System (ADS)

The semiconductor industry has pursued a rapid pace of technology scaling to achieve an exponential component cost reduction. Over the years the goal of technology scaling has been distilled down to two discrete targets. Process engineers focus on sustaining wafer costs, while manufacturing smaller dimensions whereas design engineers work towards creating newer IC designs that can feed the next generation of electronic products. In doing so, the impact of process choices made by manufacturing community on the design of ICs and vice-versa were conveniently ignored. Hoever, with the lack of cost effective lithography solutions at the forefront, the process and design communities are struggling to minimize IC die costs by following the described traditional scaling practices. In this paper we discuss a framework for quantifying the economic impact of design and process decisions on the overall product by comparing the cost-per-good-die. We discuss the intricacies involved in computing the cost-per-good-die as we make design and technology choices. We also discuss the impact of design and lithography choices for the 32nm and 22nm technology node. The results demonstrate a strong volume dependence on the optimum design style and corresponding lithography and strategy. Most importantly, using this framework process and design engineers can collaborate to define design style and lithography solutions that will lead to continued IC cost scaling.

Jhaveri, Tejas; Arslan, Umut; Rovner, Vyacheslav; Strojwas, Andrzej; Pileggi, Larry

2010-03-01

252

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

253

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

254

Titanium investiment casting defects: A metallographic overview  

NASA Astrophysics Data System (ADS)

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 of a structure: inclusions, voids, and weld repair defects.

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

2006-06-01

255

Application of submodeling technique to transient drop impact analysis of board-level stacked die packages  

Microsoft Academic Search

The objective of this research is to investigate the effects of board-level drop test based on the support excitation scheme incorporated with the submodel technique for stacked-die packages. This paper also demonstrates the transient dynamic response for lead-free SAC405 (95.5Sn4Ag0.5Cu) solder balls subject to JEDEC pulse-controlled board-level drop test standard JESD22-B110A Condition B. To evaluate the structure of the interested

Hsiang-Chen Hsu; Yu-Chia Hsu; Hui-Yu Lee; Chang-Lin Yeh; Yi-Shao Lai

2006-01-01

256

Application of artificial neural network (ANN) in the graphite morphology analysis of gray cast iron  

NASA Astrophysics Data System (ADS)

In this paper, we realize the classification of the gray cast iron according to the graphite morphology in it by Artificial Neural Network. It's a part of a big metallurgic analytical software system, and also takes on some significance in the automatic production in iron and steel industry. Our work is described as 2 steps here: The first one is texture feature extracting and the second one, classification. The images we worked on come from metallographic electron microscope, and in needs, we do some pretreatment on it. The textural features extracted mainly based on fractal parameter, roughness parameter and regression, and some comparison is also made between these textural modes. The classification is performed through artificial neural network--multilayer back-propagation neural network, which is based on a kind of feed-forward artificial neural network. It learns samples and trains itself by BP algorithm--error back propagation algorithm. To reduce the computational quantity, we obtain the number of hidden nodes directly by the numbers of input nodes and output nodes. Result shows available.

Jiang, Hong; Zeng, Libo; Zhang, Zelan; Hu, Jiming

2000-04-01

257

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

258

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

259

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

260

Beta tricalcium phosphate ceramics with controlled crystal orientation fabricated by application of external magnetic field during the slip casting process.  

PubMed

Beta tricalcium phosphate (?-TCP) is a resorbable bioceramic that has hitherto been utilized in the medical field. Since it crystallizes in the anisotropic hexagonal system, properties such as chemical and physical ones are expected to depend on its crystal axis direction and/or on its crystal plane (anisotropy). Control of crystal orientation is thus important when used in polycrystalline form. Meanwhile, application of a strong magnetic field has been found to be a promising technique to control crystal orientation of anisotropic shape or structured crystals. In this work, we attempted to fabricate ?-TCP ceramics with controlled crystal orientation by applying an external magnetic field during the slip casting process and subsequently sintering them at 1050°C, below the ?-? transition temperature. Application of a vertical magnetic field increased intensities of planes perpendicular to c-plane on the top surface, while a horizontal one with simultaneous mechanical mold rotation decreased it. These results indicated that crystal orientation of ?-TCP ceramics were successfully controlled by the external magnetic field and together that the magnetic susceptibility of ?-TCP is ?(c[perpendicular])>?(c//). PMID:23623120

Hagio, Takeshi; Yamauchi, Kazushige; Kohama, Takenori; Matsuzaki, Toshiya; Iwai, Kazuhiko

2013-03-23

261

New sol–gel refractory coatings on chemically-bonded sand cores for foundry applications to improve casting surface quality  

Microsoft Academic Search

Foundry refractory coatings protect bonded sand cores and moulds from producing defective castings during the casting process by providing a barrier between the core and the liquid metal. In this study, new sol–gel refractory coating on phenolic urethane cold box (PUCB) core was examined. The coating density, viscosity, moisture content and wet and dry weight of the coating were evaluated

U. C. Nwaogu; T. Poulsen; R. K. Stage; C. Bischoff; N. S. Tiedje

2011-01-01

262

The dental application of electroformed pure gold. II. A. Porcelain inlay. B. Cast copings with adaptable electroformed gold margins.  

PubMed

A technique for electroforming pure gold margins on the abutment castings of bridge substructures made from gold alloys or base metals alloys has been described. The margin of gold can be burnished to compensate for errors inherent in the production of these castings and ceramic procedures. A modification of this procedure permits marginal adjustment to completed crowns and bridges with deficient margins. PMID:6989351

Rogers, O W

1980-02-01

263

Powder Die Fill Study for Powder Metallurgy Applications Using New Experimental Approaches  

Microsoft Academic Search

p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Times; color: #2d2d2d} span.s1 {color: #4c4c4c} span.s2 {font: 11.0px Helvetica}\\u000ap.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Times} span.s1 {font: 11.0px Helvetica} span.s2 {font: 10.0px Verdana} span.Apple-tab-span {white-space:pre}\\u000aThe aim of this research is to enhance performance and durability of the final PM component by improving spatial density homogeneity at die

Dhanashree Aole

2010-01-01

264

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

265

ShakeCast Manual  

USGS Publications Warehouse

ShakeCast is a freely available, post-earthquake situational awareness application that automatically retrieves earthquake shaking data from ShakeMap, compares intensity measures against users? facilities, and generates potential damage assessment notifications, facility damage maps, and other Web-based products for emergency managers and responders.

Lin, Kuo-Wan; Wald, David J.

2008-01-01

266

Special Casting Techniques (Chapter 9).  

National Technical Information Service (NTIS)

Special casting techniques are progressive production methods. These casting techniques include the following: metal mold casting (chill mold casting), shell-mold casting, investment casting, centrifugal casting, and others. Each of these methods of casti...

N. P. Dubinin

1965-01-01

267

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

268

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

269

Die Energiespeicherung  

Microsoft Academic Search

\\u000a Wir haben uns daran gewöhnt, dass die für unser tägliches Leben notwendige Endenergie immer und ohne Beschränkungen zur Verfügung steht, also zu jedem Zeitpunkt und in der Menge vorhanden ist, die wir benötigen.\\u000a Dass dem so ist, liegt daran, dass die fossilen Energieträger, auf denen unsere Energieversorgung jetzt noch basiert, einen\\u000a enorm großen Energiespeicher bilden, einen Speicher für chemische Energie.

Dietrich Pelte

270

Prototype casting fabrication by stereolithography.  

National Technical Information Service (NTIS)

The evolution of the new technology of producing CAD models by ultraviolet solidification of resin materials (''STEREOLITHOGRAPHY'') continues to progress. The potential application area of rigid fabrication of prototype investment castings is becoming mo...

W. E. Cromwell

1992-01-01

271

SPHERICAL DIE  

DOEpatents

A die is presented for pressing powdered materials into a hemispherical shape of uniforin density and wall thickness comprising a fcmale and male die element held in a stationary spaced relation with the space being equivalent to the wall thickness and defining the hemispherical shape, a pressing ring linearly moveable along the male die element, an inlet to fill the space with powdered materials, a guiding system for moving the pressing ring along the male die element so as to press the powdered material and a heating system for heating the male element so that the powdered material is heated while being pressed.

Livingston, J.P.

1959-01-27

272

Application of hydrogen sensor using proton conductive ceramics as a solid electrolyte to aluminum casting industries  

Microsoft Academic Search

A galvanic cell type of hydrogen sensor was developed using CaZrO3-based proton conductor as a solid electrolyte. It was clear that the hydrogen sensor could be used for the accurate determination of hydrogen concentration in molten aluminum alloys. The sensor probe exhibited stable EMF values and a fast response when the hydrogen concentration in the melt was changed. The application

Tamotsu Yajima; Kunihiro Koide; Haruki Takai; Nirihiko Fukatsu; Hiroyasu Iwahara

1995-01-01

273

Evaluation of cast Ti–Fe–O–N alloys for dental applications  

Microsoft Academic Search

Good mechanical properties, biocompatibility and corrosion resistance make titanium an excellent material for biomedical applications. However, when better mechanical properties than those offered by commercially pure titanium (CPTi) are needed, Ti–6Al–4V is sometimes a good alternative. Some new titanium alloys, developed as industrial structural materials, aim at an intermediate range of strength between that of CP Ti and Ti–6Al–4V. Two

Marie Koike; Chikahiro Ohkubo; Hideki Sato; Hideki Fujii; Toru Okabe

2005-01-01

274

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

275

CASTING FURNACES  

DOEpatents

A device is described for casting uranium which comprises a crucible, a rotatable table holding a plurality of molds, and a shell around both the crucible and the table. The bottom of the crucible has an eccentrically arranged pouring hole aligned with one of the molds at a time. The shell can be connected with a vacuum.

Ruppel, R.H.; Winters, C.E.

1961-01-01

276

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.

277

Full-crown castings made with water-saturated and dry casting ring liners.  

PubMed

The carcinogenic potential of asbestos has led to the development of non-asbestos materials for use as casting ring liners. Cellulose paper are replacing asbestos paper. The brass die and crown were made to produce full crowns. The standardized wax pattern was replicated twenty-nine times. Two grooves were marked on the die and wax patterns. The marginal gaps between wax pattern and die shoulder were measured. Then, the wax specimens were divided into three groups. The dry ring liner and the water-saturated ring liner were used, in the third group, any liner was used. The castings were fabricated and were fitted on the die. Measurements were made of the distance separating the gingival margin of the castings from the shoulder on the die. Measurement points (X and Y) were the same points used for wax pattern measurement. The difference between wax pattern and casting was found to be statistically significant in all the groups (p = 0.0051). There was no statistically significant difference between groups on the comparative fit of the castings. The mean marginal space in the water-saturated liner group was 0.51 +/- 0.12 mm (X), 0.51 +/- 0.11 mm (Y), and in the dry liner group, the mean marginal space was 0.47 +/- 0.09 mm (X), 0.49 +/- 0.08 mm (Y). In the unlined group, they were 0.52 +/- 0.18 mm (X), 0.55 +/- 0.17 mm (Y). Use of dry ring lining material resulted in smaller marginal spaces between castings and the die than use of water-saturated cellulose ring lining material. The results demonstrated that the use of dry liners may improve the fit of castings to dies. PMID:10794510

Keyf, F; Erman, G

2000-04-01

278

Micromechanical die attachment surcharge  

DOEpatents

An attachment structure is disclosed for attaching a die to a supporting substrate without the use of adhesives or solder. The attachment structure, which can be formed by micromachining, functions purely mechanically in utilizing a plurality of shaped pillars (e.g. round, square or polygonal and solid, hollow or slotted) that are formed on one of the die or supporting substrate and which can be urged into contact with various types of mating structures including other pillars, a deformable layer or a plurality of receptacles that are formed on the other of the die or supporting substrate, thereby forming a friction bond that holds the die to the supporting substrate. The attachment structure can further include an alignment structure for precise positioning of the die and supporting substrate to facilitate mounting the die to the supporting substrate. The attachment structure has applications for mounting semiconductor die containing a microelectromechanical (MEM) device, a microsensor or an integrated circuit (IC), and can be used to form a multichip module. The attachment structure is particularly useful for mounting die containing released MEM devices since these devices are fragile and can otherwise be damaged or degraded by adhesive or solder mounting.

Filter, William F. (Albuquerque, NM); Hohimer, John P. (Albuquerque, NM)

2002-01-01

279

Prototype casting fabrication by stereolithography  

SciTech Connect

The evolution of the new technology of producing CAD models by ultraviolet solidification of resin materials ( STEREOLITHOGRAPHY'') continues to progress. The potential application area of rigid fabrication of prototype investment castings is becoming more feasible as we continue to successfully yield experimental castings by the SHELL'' processing method. This supplemental (to 11/90 publication) report briefly reviews the original project objectives, activities related to these objectives since November 1990, and progress made through December 1991. We discuss several new case studies involving new resin materials (and other materials) tested along with investment casting processing results. The most recent success, the processing of the highly complex C'' HOUSING design by the shell'' mold process in both aluminum and steel, will be discussed. This is considered a major breakthrough toward establishing this new technology as a viable approach to the rapid development of prototype investment castings, employing the most common aerospace (precision) cast process. Our future planning calls for expanding the study to help the investment casting industry in refining related processing techniques and to continue our evaluation of new resins suitable for the casting process. Present project planning calls for the completion of this study by the third quarter FY93 or sooner. We believe that with the continued excellent cooperation of our casting supplier study team and an accelerated effort by resin materials producers to further refine related materials, we can achieve all objectives during the planned time frame.

Cromwell, W.E.

1992-03-01

280

Prototype casting fabrication by stereolithography  

SciTech Connect

The evolution of the new technology of producing CAD models by ultraviolet solidification of resin materials (``STEREOLITHOGRAPHY``) continues to progress. The potential application area of rigid fabrication of prototype investment castings is becoming more feasible as we continue to successfully yield experimental castings by the ``SHELL`` processing method. This supplemental (to 11/90 publication) report briefly reviews the original project objectives, activities related to these objectives since November 1990, and progress made through December 1991. We discuss several new case studies involving new resin materials (and other materials) tested along with investment casting processing results. The most recent success, the processing of the highly complex ``C`` HOUSING design by the ``shell`` mold process in both aluminum and steel, will be discussed. This is considered a major breakthrough toward establishing this new technology as a viable approach to the rapid development of prototype investment castings, employing the most common aerospace (precision) cast process. Our future planning calls for expanding the study to help the investment casting industry in refining related processing techniques and to continue our evaluation of new resins suitable for the casting process. Present project planning calls for the completion of this study by the third quarter FY93 or sooner. We believe that with the continued excellent cooperation of our casting supplier study team and an accelerated effort by resin materials producers to further refine related materials, we can achieve all objectives during the planned time frame.

Cromwell, W.E.

1992-03-01

281

A Methodology to Predict Fatigue Life of Cast Iron: Uniform Material Law for Cast Iron  

Microsoft Academic Search

Mechanical, physical and manufacturing properties of cast iron make it attractive for many fields of application, such as cranks and cylinder holds. As in design of all metals, fatigue life prediction is an intrinsic part of the design process of structural sections that are made of cast iron. A methodology to predict high-cycle fatigue life of cast iron is proposed.

Sinan Korkmaz

2011-01-01

282

Novel compensation chemical metal polishing for low dishing and high global planarity for ultra-planar die applications in micro-optics and micro-electro-mechanical systems  

Microsoft Academic Search

Some recent micro-optical applications require die planarity on the scale of a fraction of wavelength of light. A novel chemical mechanical polishing (CMP) process on a damascene structure is described for such requirements. We present an approach that decouples obtaining patterning and planarity, into separate steps, not only to better control metal dishing but also to establish a high degree

Udayan Ganguly; J. Peter Krusius

2004-01-01

283

USGS ShakeCast  

USGS Publications Warehouse

Automating, Simplifying, and Improving the Use of ShakeMap for Post-Earthquake Decisionmaking and Response. ShakeCast is a freely available, post-earthquake situational awareness application that automatically retrieves earthquake shaking data from ShakeMap, compares intensity measures against users facilities, and generates potential damage assessment notifications, facility damage maps, and other Web-based products for emergency managers and responders.

Wald, David; Lin, Kuo-Wan

2007-01-01

284

AGARD handbook on advanced casting  

NASA Astrophysics Data System (ADS)

The need to improve aircraft performance and, simultaneously, to reduce costs has led to a re-examination of the use of casting processes in aircraft manufacture. The Structures and Materials Panel of AGARD has provided practical information about design, mechanical values, applications, quality assurance and damage tolerance. By providing the data in this form it is hoped that the designer will be encouraged to exploit the many recent advances in casting to optimum effect.

Mietrach, Dietmar

1991-03-01

285

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

286

Off-centric extrusion of circular rods through streamlined dies, CAD\\/CAM applications, analysis and some experiments  

Microsoft Academic Search

The previously given analytical method [1], which was based on the upper-bound theory, was used to design the streamlined dies and to investigate the three dimensional off-centric extrusion of circular sections from initially circular billets through linearly converging (ruled-surface) and smooth curved (advancedsurface) dies. For a reasonably correct upper-bound to the load, a set of generalised kinematically admissible velocity fields

K. F. Celik; N. R. Chitkara

2000-01-01

287

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

Federal Register 2010, 2011, 2012, 2013

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

2011-02-02

288

Cast Aluminum Structures Technology, Phase III (Cast).  

National Technical Information Service (NTIS)

The objective of CAST is to establish the necessary structural and manufacturing technologies and to demonstrate the validate the integrity, producibility, and viability of cast aluminum primary airframe structures. The baseline design is the AMST prototy...

D. Goehler

1978-01-01

289

Tensile, creep, and low-cycle fatigue behavior of a cast ? -TiAl-based alloy for gas turbine applications  

Microsoft Academic Search

The influence of chemical composition on the microstructure of the ?-titanium aluminide alloy Ti-48Al-2W-0.5Si (at. pct) and the accompanying tensile, low-cycle fatigue, and creep properties\\u000a has been evaluated. The study showed that small variations in chemical composition and casting procedures resulted in considerable\\u000a variations in the microstructure, yielding vastly different mechanical properties. Low contents of aluminum and tungsten led\\u000a to

V. Recina; D. Lundström; B. Karlsson

2002-01-01

290

Creep Behavior of AsCast Ti48Al2Cr Intermetallic Alloy for Aerospace and Automotive Applications  

Microsoft Academic Search

The creep properties of as-cast Ti-48Al-2Cr (at%) alloy which had been strengthen with addition of 2 at% Cr were investigated. Tensile creep experiments were performed in air at temperatures from 600–800°C and initial stresses ranging from 150 to 180 MPa. Stress exponent and activation energy were both measured. Data indicates that the alloy exhibits steady state creep behavior and the

E. Hamzah; M. Kanniah; M. Harun

2007-01-01

291

Squeeze Casting of Steel Weapon Components.  

National Technical Information Service (NTIS)

The project was initiated to study the feasibility of applying the squeeze casting process to produce two specific steel weapon components - the receiver base and the barrel support of the M85 weapon. Dies were designed and fabricated for both components ...

D. A. Stawarz K. M. Kulkarni K. R. Iyer R. B. Miclot

1974-01-01

292

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

293

An unusually severe case of the cast syndrome  

Microsoft Academic Search

A severe case of the cast syndrome is described following Harrington rod distraction and application of a body cast. The case was unusual as it presented late with no warning symptoms and progressed rapidly to death.

R. H. Kennedy; M. J. Cooper

1983-01-01

294

Casting shape optimisation via process modelling  

Microsoft Academic Search

The paper describes the application of numerical optimisation case studies to two practical cast components. The first study highlights the potential benefit of thermal controls to achieve an optimised cast part, whereas, the second focuses on shape optimisation. In comparison with practice, it was noted that the unconstrained optimisation for thermal control identified the improvement path correctly, but the solution

R. W Lewis; M. T Manzari; R. S Ransing; D. T Gethin

2000-01-01

295

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

PubMed

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

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

1990-07-01

296

Structure and properties of dies obtained from scrap of 5KhNM and R6M5 steels by electroslag remelting  

Microsoft Academic Search

It is known that in a number of cases cast dies of tool steels for hot working possess increased life. In the Lozovaya Forging and Machining Plant in electroslag remelting (ESR) of worn dies, a method is used making it possible to improve the quality of the cast blanks (dies) by additional alloying of them. A consumable composite electrode made

E. I. Timchenko; L. M. Semenova; Yu. A. Berezkin; I. D. Zaitseva

1987-01-01

297

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

298

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

299

Tape-cast and sintered ?-tricalcium phosphate laminates for biomedical applications: Effect of milled Al2O3 fiber additives on microstructural and mechanical properties.  

PubMed

The aim of this study was to develop the tape-cast, laminated, and sintered ?-tricalcium phosphate (?-TCP) with milled Al(2)O(3) fibers for biomedical applications. Moreover, the effects of Al(2)O(3)-fiber content on the microstructural and mechanical properties of the sintered ?-TCP laminates were investigated. The milled Al(2)O(3) fibers were added at four different contents, namely 0, 5, 10, or 15 mass%, to the initial ?-TCP slurry. Next, ?-TCP green sheets were fabricated from the ?-TCP slurry containing the milled Al(2)O(3) fibers by a tape-casting method. Finally, six plies of ?-TCP monolayer sheet were laminated and sintered at a maximum temperature of 1100°C in a furnace. The results showed that there were large differences between the apparent porosities, dynamic hardness, and flexural properties of the sintered ?-TCP laminates with Al(2)O(3)-fiber contents of 0 and 5 mass%, but few differences among laminates with fiber contents of 5, 10, and 15 mass%. This indicates that the addition of only 5 mass% of Al(2)O(3) fibers strongly affects the degree of sintering, corresponding to crystallization of the ?-TCP matrix phase. Furthermore, the flexural moduli of our materials ranged from 10.7 to 16.0 GPa when the Al(2)O(3)-fiber content changed from 5 to 15 mass% and were the almost same as those of human bones reported by other researchers. In conclusion, sintered ?-TCP laminates with Al(2)O(3) fibers have potential uses in a wide range of biomedical applications because the microstructural and mechanical properties of the sintered ?-TCP laminates can be controlled by adding Al(2)O(3) fibers to the ?-TCP. PMID:22887746

Tanimoto, Yasuhiro; Teshima, Masahiro; Nishiyama, Norihiro; Yamaguchi, Masaru; Hirayama, Satoshi; Shibata, Yo; Miyazaki, Takashi

2012-08-11

300

A Benchmark Study on Casting Residual Stress  

SciTech Connect

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

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

2012-01-01

301

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

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

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

302

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

Federal Register 2010, 2011, 2012, 2013

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

2010-11-12

303

Flow impact on cast ingots  

NASA Astrophysics Data System (ADS)

Aluminium alloys are a standard cast metal used in a number of automotive and transportation applications, allowing manufacturers to reduce vehicle weight, increase the strength of components and improve emission controls. One of the most challenging problems associated with aluminium casting is the influence of convection during all stages of solidification. The strength of fluid flow changes the as-cast internal structure (microstructure) such that the yield, fracture and fatigue strengths of the cast ingot can vary considerably. Although the importance of fluid flow has been recognised for decades, not even a simple model has been developed to predict the effect on microstructure. The MICAST project aims to identify and control experimentally the fluid-flow patterns that affect microstructure evolution during casting processes, and to develop analytical and advanced numerical models. The microgravity environment of the International Space Station and sounding rockets is of special importance to this project because only there are all gravity-induced convections eliminated and well-defined conditions for solidification prevail that can be disturbed by fluid flow controlled by experimenters.

Ratke, Lorenz; Fautrelle, Yves; Lacaze, Jacques; Müller, Georg; Roosz, Andras; Zimmermann, Gerhard; Jarry, Phillippe; Kieft, Rene; Csepeli, Zsolt; Sándor, Józef; Grün, Gerd-Ulrich; Sillinger, Nándor; Gerke-Cantow, Ralf

2005-10-01

304

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

PubMed Central

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

Viswambaran, M.; Agarwal, S. K.

2013-01-01

305

The effect of Sr and Fe additions on the microstructure and mechanical properties of a direct squeeze cast Al7Si0.3Mg alloy  

Microsoft Academic Search

This article describes the results of an investigation into the microstructure and mechanical properties of a gravity die\\u000a cast and direct squeeze cast LM25 alloy (Al-7Si-0.3Mg-0.3Fe). The direct squeeze cast LM25 alloy has superior mechanical properties\\u000a compared to the gravity die cast LM25 alloy, especially with regard to ductility, which is increased from ?1.7 pct for the\\u000a gravity die cast

J. X. Dong; P. A. Karnezis; G. Durrant; B. Cantor

1999-01-01

306

Highly conductive die attach adhesive from percolation control and its applications in light-emitting device thermal management  

NASA Astrophysics Data System (ADS)

Herein, we reported on the study of percolation dynamics in thermoset-based die attach (DA) materials and its effect on percolation conductivity. Two types of percolation mechanism in thermoset based DA were discovered, i.e., the curing reaction-induced percolation and the physical aging-induced percolation. The former features in a fast percolation network growth rate, which is one order of magnitude higher than the latter. It is demonstrated that the percolation kinetics largely affects the apparent percolation conductivity under the traditional packaging conditions; and reaction-induced percolation allows ultrahigh efficiency in reaching the volume fraction-limiting percolation conductance, resulting in enhanced thermal performance of DA.

Zhang, Xinfeng; Zhang, Kai; Zhang, Min; Yang, Chen; Sun, Hongye; Gao, Zhaoli; Yuen, Matthew M. F.; Yang, Shihe

2013-01-01

307

Opportunities for Conversion of Powertrain Components from Malleable\\/Ductile Cast Irons to Powder Metallurgy  

Microsoft Academic Search

Malleable and ductile cast irons are used extensively in gearing and high strength applications within automotive power train applications. Advantages of malleable and ductile cast irons are low material cost with mechanical properties that meet or exceed the requirements of the intended application(s). One disadvantage of the malleable cast iron is the extensive heat treating required to obtain the proper

Francis Hanejko; Arthur Rawlings; Robert Causton

308

A new methodology for measurement of semi-solid constitutive behavior and its application to examination of as-cast porosity and hot tearing in aluminum alloys  

Microsoft Academic Search

Hot tearing and as-cast porosity are the two defects which impede the performance of cast products. The effect of porosity on hot tearing was investigated using a novel semi-solid tensile deformation methodology combined with X-ray micro-tomography. Semi-solid deformation tests were conducted on the commercial aluminium–magnesium alloy AA5182 in the as-cast state. This material was tested in two forms: as-received and

A. B. Phillion; S. L. Cockcroft; P. D. Lee

2008-01-01

309

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

310

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

311

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

312

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

313

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

NASA Astrophysics Data System (ADS)

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

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

2007-12-01

314

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

315

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...

316

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...

317

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

318

Analytical stress modeling of high-energy laser windows: Application to fusion-cast calcium fluoride windows  

NASA Astrophysics Data System (ADS)

The performance of a laser-window material must be assessed not only in terms of its ability to transmit high-power beams without generating undue optical distortion but also in terms of the constraints imposed by stress-related failure modes. In operational use, the stress field images the superposition of stresses originating from the mechanical load created by the pressure differential and the thermal load created by the laser beam. Here, we provide the tools to carry out an analysis of both pressure- and beam-induced stresses, and illustrate the procedure in the context of assessing the performance of a ``model'' window made of fusion-cast CaF2. The analysis assumes (a) operation on a time scale such that lateral heat diffusion can be ignored, and (b) cylindrically symmetric Gaussian beam shapes, which permit straightforward calculations of stress distributions that should be representative of worst case situations. Pressure-induced stresses strongly depend on the window's aspect ratio, which suggests increasing the thickness to minimize the stress, but considerations relating to the optical performance require minimum allowable thicknesses based on a Weibull statistical analysis of the fracture probability. Beam-induced stresses are best evaluated in terms of (a) thickness-averaged radial and azimuthal stresses, which increase linearly with exposure time and depend on radial distances through the truncation parameter, and (b) across-the-thickness stress deviations relative to the average stress, which are caused by surface absorption and reach steady-state configurations on a time scale much shorter than the characteristic time for lateral heat transport. The average stress is always compressive and equibiaxial in the central region of the window, but its azimuthal component turns tensile in the rim region, thus threatening the structural integrity through brittle fracture. In addition, the coating-induced stress results in on-axis surface compressions that may exceed the yield strength of the windowpane material. In this light we formulate a figure of merit for stress, which demonstrates that promising laser-window materials must combine a small stress factor (expansion coefficient times elastic modulus) with superior thermal properties in terms of the product of heat capacity and thermal conductivity; CaF2 and SrF2 are the only known candidates that exhibit outstanding optical features at chemical laser wavelengths together with acceptable thermomechanical properties.

Klein, Claude A.

2005-08-01

319

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

320

Tape Casting Method and Tape Cast Materials.  

National Technical Information Service (NTIS)

A precursor tape casting method is one in which chemical precursors are converted into a final chemical phase from green tapes to products. Because chemical precursors are employed rather than the final powder materials, sintering is not required to form ...

D. Xiao M. Wu S. Hui Y. Zhang

2005-01-01

321

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

322

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

323

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

324

Investment casting of gold jewellery  

Microsoft Academic Search

The lost wax or investment casting process used extensively in gold jewellery fabrication is subject to the effects of a large\\u000a number of process variables. One consequence of this is that where problems arise or exist in its application, they can be\\u000a difficult to understand and solve. In order to promote optimization of the process the authors have studied the

Dieter Ott; Christoph J. Raub

1985-01-01

325

Tape casting of lanthanum chromite  

Microsoft Academic Search

Solid oxide fuel cells (SOFCs) are currently being developed for a variety of applications such as stationary on-site power plants and cogeneration. The effects of process additives, ball milling, and solids loading were evaluated for tape casting suspensions of glycine-nitrate-synthesized La{sub 0.7}Ca{sub 0.31}CrOâ powder. An optimized formulation was obtained based on rheological characterization, electrokinetic sonic amplitude measurements, qualitative examination of

Michael W. Murphy; Timothy R. Armstrong; Peter A. Smith

1997-01-01

326

Applicability of Carbon Fibers in Heavily Stressed Aircraft Components Untersuchungen ueber die Anwendung von Kohlenstoff-Fasern in Hochbeanspruchten Flugzeugbauteilen.  

National Technical Information Service (NTIS)

The feasibility of using carbon fiber reinforced plastics (CRP) for primary wing structures of aircraft was investigated. Strength and stiffness of CRP were determined with regard to application in wing spars and torsion boxes. Production methods for glas...

D. Muehlhahn H. Treiber W. Mischke

1973-01-01

327

Effects of chromium and nitrogen content on the microstructures and mechanical properties of as-cast Co-Cr-Mo alloys for dental applications.  

PubMed

The microstructure and mechanical properties of as-cast Co-(20-33)Cr-5Mo-N alloys were investigated to develop ductile Co-Cr-Mo alloys without Ni addition for dental applications that satisfy the requirements of the type 5 criteria in ISO 22674. The effects of the Cr and N contents on the microstructure and mechanical properties are discussed. The microstructures were evaluated using scanning electron microscopy with energy-dispersive X-ray spectroscopy (EDS), X-ray diffractometry (XRD), and electron back-scattered diffraction pattern analysis. The mechanical properties were evaluated using tensile testing. The proof strength and elongation of N-containing 33Cr satisfied the type 5 criteria in ISO 22674. ?-phase with striations was formed in the N-free (20-29)Cr alloys, while there was slight formation of ?-phase in the N-containing (20-29)Cr alloys, which disappeared in N-containing 33Cr. The lattice parameter of the ?-phase increased with increasing Cr content (i.e. N content) in the N-containing alloys, although the lattice parameter remained almost the same in the N-free alloys because of the small atomic radius difference between Co and Cr. Compositional analyses by EDS and XRD revealed that in the N-containing alloys Cr and Mo were concentrated in the cell boundary, which became enriched in N, stabilizing the ?-phase. The mechanical properties of the N-free alloys were independent of the Cr content and showed low strength and limited elongation. Strain-induced martensite was formed in all the N-free alloys after tensile testing. On the other hand, the proof strength, ultimate tensile strength, and elongation of the N-containing alloys increased with increasing Cr content (i.e. N content). Since formation of ?-phase after tensile testing was confirmed in the N-containing alloys the deformation mechanism may change from strain-induced martensite transformation to another form, such as twinning or dislocation slip, as the N content increases. Thus the N-containing 33Cr alloy with large elongation is promising for use in dentures with adjustable clasps through one piece casting. PMID:22430232

Yoda, Keita; Suyalatu; Takaichi, Atsushi; Nomura, Naoyuki; Tsutsumi, Yusuke; Doi, Hisashi; Kurosu, Shingo; Chiba, Akihiko; Igarashi, Yoshimasa; Hanawa, Takao

2012-03-17

328

Casting Design Knowledge Management  

Microsoft Academic Search

India has a global competitive advantage in medium-volume engineering-intensive metal products, such as automobile castings. To maintain and enhance this advantage, foundries need to adopt a systematic approach to preserve and reuse their in-house knowledge accumulated through years of experience. In this paper, we present a casting knowledge management system that facilitates: (1) capturing and updating casting knowledge in the

B. Ravi

329

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 15–20% Al content as

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

2008-01-01

330

Some Economic Implications of Caste  

Microsoft Academic Search

This paper compares outcomes across two types of villages in a poor region of rural India. The two types of villages systematically vary by which caste is dominant, i.e., the caste group which owns the majority of land. The dominant caste is either from an upper caste or a lower backward caste. The key finding is that income is substantially

Siwan Anderson

331

Evolution of halictine castes  

NASA Astrophysics Data System (ADS)

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

Knerer, Gerd

1980-03-01

332

Migration of crystals during the filling of semi-solid castings  

Microsoft Academic Search

In cold-chamber high-pressure die castings (HPDC), the microstructure consists of coarse externally solidified crystals (ESCs)\\u000a that are commonly observed in the central region of cross sections. In the present work, controlled laboratory scale casting\\u000a experiments have been conducted with particular emphasis on the flow and solidification conditions. An A356 aluminum alloy\\u000a was used to produce castings by pouring semi-solid metal

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

2005-01-01

333

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

334

Cast Aluminum Structures Technology (CAST) Manufacturing Methods--Phase II.  

National Technical Information Service (NTIS)

The objective of CAST is to establish the necessary structural and manufacturing technologies and to demonstrate and validate the integrity, producibility, and viability of cast aluminum primary airframe structures. The necessary casting foundry practices...

D. D. Goehler R. G. Christner

1978-01-01

335

INTERIOR VIEW WITH LARGE PIPE CASTING MACHINE CASTING A 48' ...  

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

INTERIOR VIEW WITH LARGE PIPE CASTING MACHINE CASTING A 48' PIPE. - United States Pipe & Foundry Company Plant, Pipe Casting & Testing Area, 2023 St. Louis Avenue at I-20/59, Bessemer, Jefferson County, AL

336

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

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

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

337

Reheating process of cast and wrought aluminum alloys for thixoforging and their globularization mechanism  

Microsoft Academic Search

A thixoforging process has numerous advantages compared to die casting, squeeze casting, and conventional forging. For the thixoforging process, beside a co-existing solidus–liquidus interval, the reheating conditions to obtain a fine globular microstructure are very important. During reheating, the eutectic must be remelted completely in order to obtain good mechanical properties. The solid fraction distribution over temperature, the phase distribution

H. K Jung; C. G Kang

2000-01-01

338

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

339

Feasibility of Squeeze Casting the Base for the PATRIOT Warhead XM248E1.  

National Technical Information Service (NTIS)

Squeeze casting is a hybrid of permanent mold casting and forging techniques. In this metalworking process molten metal is metered into a die cavity and pressure is applied to the solidifying metal. Suitable use of the optimized process parameters can eli...

A. Chakravartty

1979-01-01

340

CASTE (Course Assembly System and Tutorial Environment) and CVI: (Combat Vehicle Identification) A First Application of an Intelligent Tutorial System to Combat Vehicle Identification.  

National Technical Information Service (NTIS)

This research report describes an intelligent tutorial delivery system called CASTE and its complement, an authoring and representation system called THOUGHTSTICKER. The prototype system runs on an Apple microcomputer and is aimed principally at the eluci...

D. Gregory

1984-01-01

341

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 (á=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

342

Application of a casting-rolling unit in a combined process of production of high-quality products from copper scrap  

NASA Astrophysics Data System (ADS)

A highly efficient technology of processing of copper scrap is considered: it implies a combination of melting, refining, casting, and rolling to produce high-quality copper products. The characteristics and parameters of the main element of this technology (casting-rolling unit) and its most important functional element (mold), which substantially affects the unit capacity and the quality of the forming billet, are described.

Smirnov, A. N.; Shutov, I. V.; Kuberskii, S. V.; Volkov, S. M.

2012-12-01

343

Development of casting investment preventing blackening of noble metal alloys part 1. Application of developed investment for Ag-Pd-Cu-Au alloy.  

PubMed

The objective of this study is to develop a casting investment that prevents the blackening of the cast surface of noble metal alloys. The experimental investments were prepared using a gypsum-bonded investment in which the metallic powders such as boron (B), silicon (Si), aluminum (Al) and titanium (Ti) were added as oxidizing agents. An Ag-Pd-Cu-Au alloy was cast into the mold made of the prepared investment. The effect of the addition of each metal powder was evaluated from the color difference between the as-cast surface and the polished surface of the cast specimen. The color of the as-cast surface approached that of the polished surface with increasing B and Al content. A lower mean value in the color difference was obtained at 0.25-1.00 mass% B content. B and Al are useful as an additive in a gypsum-bonded investment to prevent the blackening of an Ag-Pd-Cu-Au alloy. The effects of Si and Ti powder addition could not be found. PMID:12790300

Kakuta, Kiyoshi; Nakai, Akira; Goto, Shin-ichi; Wakamatsu, Yasushi; Yara, Atushi; Miyagawa, Yukio; Ogura, Hideo

2003-03-01

344

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

345

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

346

LLNL casting technology.  

National Technical Information Service (NTIS)

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 ...

A. B. Shapiro W. J. Comfort

1994-01-01

347

Vitamin E in cardiovascular disease: has the die been cast?  

Microsoft Academic Search

Cardiovascular disease, in particular coronary artery disease (CAD), remains the most important cause of morbidity and mortality in developed countries and, in the near future, more so in the developing world. Atherosclerotic plaque formation is the underlying basis for CAD. Growth of the plaque leads to coronary stenosis, causing a progressive decrease in blood flow that results in angina pectoris.

Khalid Yusoff

2002-01-01

348

Expendable Pattern Casting Technology  

NASA Astrophysics Data System (ADS)

The expendable pattern casting (EPC) process is a potential casting process breakthrough which could dramatically improve the competitiveness of the U.S. foundry industry. Cooperatively supported by U.S. Industry and the Department of Energy and managed by the American Foundrymen's Society, a project was started in May 1989 to develop and optimize expendable pattern casting technology. Four major tasks were conducted in the first phase of the project. Those tasks involved: (1) reviewing published literature to determine the major problems in the EPC process; (2) evaluating factors influencing sand flow and compaction; (3) evaluating and comparing casting precision obtained in the EPC process with that obtained in other processes; and (4) identifying critical parameters that control dimensional precision and defect formation in EP castings.

1990-07-01

349

Material properties for predicting wax pattern dimensions in investment casting  

Microsoft Academic Search

An important factor in determining tooling allowances in investment casting is the dimensional change of the wax pattern. Dimensional changes between a pattern die and its wax pattern occur as a result of complex phenomena such as thermal expansion–contraction and hot deformation (elastic, plastic, and creep). Thus, the wax pattern dimensions are determined by the wax’s thermophysical and thermomechanical properties,

Adrian S Sabau; Srinath Viswanathan

2003-01-01

350

Influence of Processing Route on Fatique Behaviour of Investment Cast High Strength Steels.  

National Technical Information Service (NTIS)

The suitability of different bar stock conditions, casting methods and HIPing treatments to produce clean, sound, high integrity, ferrous investment castings for fatigue-rated applications has been investigated. Fatigue tests at two stress ratios revealed...

R. McCallum W. Lang

1985-01-01

351

Aqueous suspensions for tape-casting based on acrylic binders  

Microsoft Academic Search

The use of water-based systems represents an interesting alternative to the widespread non-aqueous tape-casting but the low strength of water-based binders generally limits their applicability. A tape-casting slurry is a complex system where each organic component has a substantial effect on the rheological behaviour. In this study the effect of the dispersant and binders in alumina aqueous tape-casting slurries were

C. Pagnoux; T. Chartier; M. de F. Granja; F. Doreau; J. M. Ferreira; J. F. Baumard

1998-01-01

352

Using cold-crucible melting for titanium precision castings  

NASA Astrophysics Data System (ADS)

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

Broihanne, Georges; Bannister, John

2000-05-01

353

Parameter Optimization for Mould and Die Recovering Using Laser Cladding  

NASA Astrophysics Data System (ADS)

In the last years the laser cladding has become an important technology that has been studied by several industries as automotive or aeronautical. Therefore, although this technology was used initially for coatings, actually it is being used for repairing or even direct manufacturing of high added value parts. In this paper, the application of laser cladding for repairing a GGG70L stamping die is presented. The first step is to present the methodology used to obtain the optimum conditions for AISI 316L stainless steel clads on structural steel (DIN C45). The next section shows a deeper study about the capacity of the process to fill standard geometries on DIN C45 and DIN 1.2379. Finally, a nodular cast iron GGG70L stamping die is repaired using laser cladding process. The parameters and strategy used for the repairing have been obtained on previous sections. Furthermore, in the final section a powder concentration model is presented as the first step to create a complete model that simulate the three stages of laser cladding: interaction between powder and laser beam, creation of melt pool and generation of clad geometry.

Tabernero, I.; Lamikiz, A.; Ukar, E.; Arregi, B.; Figueras, J.; Soriano, C.

2009-11-01

354

Development of casting investment preventing blackening of noble metal alloys Part 2. Application of developed investment for type 4 gold alloy.  

PubMed

The objective of this study was to evaluate the efficacy of the developed investment for the prevention of blackening of a cast Type 4 gold and to analyze the oxides on its surface in relation to the blackening of the alloy. The experimental investments were prepared using a gypsum-bonded investment in which boron (B) or aluminum (Al) was added as a reducing agent. A Type 4 gold alloy was cast into the mold made of the prepared investment. The effect of the additives was evaluated from the color difference (deltaE*) between the as-cast surface and the polished surface of the cast specimen. B and Al were effective to prevent the blackening of a Type 4 gold alloy and the color of the as-cast surface approached that of the polished surface with increasing B and Al content. The prevention of the blackening of the gold alloy can be achieved by restraining the formation of CuO. PMID:14620998

Nakai, Akira; Kakuta, Kiyoshi; Goto, Shin-ichi; Kato, Katuma; Yara, Atushi; Ogura, Hideo

2003-09-01

355

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

SciTech Connect

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

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

2011-02-27

356

Solidification process and infrared image characteristics of permanent mold castings  

NASA Astrophysics Data System (ADS)

Interdependence between the development of temperature gradients at the solid-liquid interface during solidification of metals and the formation of local defects demands for thermal investigation. In foundry practice thermocouples are used to control the die's overall cooling-rate, but fluctuations in product quality still occur. Capturing FIR- thermograms after opening the die visualizes the state, when most thermal throughput has already flattened the temperature gradients in the mold. Rapid dissipation of heat from liquid metal to the mold during solidification forces further approach of the process investigation by slowing down the heat flux or the use of transparent mold material. Aluminum gravity casting experiments under technical vacuum conditions lead to decelerated solidification by suppression of convection and image sequences containing explicit characteristics that could be assigned to local shrinkage of the casting. Hence relevant clusters are extracted and thermal profiles are drawn from image series, pointing out correlations between feeding performance from the sink heads and the appearance of local defects. Tracing thermal processes in vacuum casting can scarcely be transferred to image data in foundry practice, since only little analogies exist between atmospheric and vacuum casting. The diagnosis of the casting process requires detection of the still closed mold using a transparent silica- aerogel sheet as part of the die. Hereby thermograms of the initial heat input are recorded by adapting a NIR-camera in addition to the FIR-unit. Thus the entire thermal compensation at the joint face for each casting is visualized. This experimental set-up is used for image sequence analysis related to the intermediate casting phases of mold filling, body formation and solidification shrinkage.

Viets, Roman; Breuer, Markus; Haferkamp, Heinz; Kruessel, Thomas; Niemeyer, Matthias

1999-03-01

357

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.

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

1994-01-01

358

Tape casting of lanthanum chromite  

SciTech Connect

Solid oxide fuel cells (SOFCs) are currently being developed for a variety of applications such as stationary on-site power plants and cogeneration. The effects of process additives, ball milling, and solids loading were evaluated for tape casting suspensions of glycine-nitrate-synthesized La{sub 0.7}Ca{sub 0.31}CrO{sub 3} powder. An optimized formulation was obtained based on rheological characterization, electrokinetic sonic amplitude measurements, qualitative examination of green tapes, and the sintered microstructure. The tape casting formulation incorporated 66:34 methyl ethyl ketone/ethyl alcohol solvent, an aliphatic phosphate ester dispersant, and 80 wt% (35 vol%) solids. The best binder/plasticizer system was 12 wt% (15 vol%) poly(isobutyl methacrylate) and 5 wt% (6.3 vol%) benzyl butyl phthalate plasticizer (binder:plasticizer = 2.3). Cast tapes were sintered at 1300 C for 2 h, producing a bulk density of 96.2% theoretical, with linear shrinkage of 22% and an approximate grain size of 1.3 {micro}m.

Murphy, M.W.; Armstrong, T.R.; Smith, P.A. [Pacific Northwest National Lab., Richland, WA (United States)

1997-01-01

359

CENTRIFUGAL CASTING MACHINE  

DOEpatents

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

Shuck, A.B.

1958-04-01

360

Displaced capillary dies  

DOEpatents

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

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

1984-01-01

361

Displaced capillary dies  

DOEpatents

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

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

1982-01-01

362

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

363

Silica exposure in hand grinding steel castings.  

PubMed

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

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

1992-01-01

364

Die Mehrheit entscheidet. Wirklich?  

Microsoft Academic Search

Hätte es den Irak-Krieg auch gegeben, wenn nicht George W. Bush, sondern Albert A. Gore die amerikanischen Präsidentschaftswahlen\\u000a des Jahres 2000 gewonnen hätte? Viel spricht für die Vermutung, dass dem nicht so wäre. Hätte Kanzler Gerhard Schröder die\\u000a Bundestagswahlen 2002 auch gewinnen können, ohne das Irak-Thema wahltaktisch zu besetzen? Wiederum spricht vieles für die\\u000a Vermutung, dass dem nicht so wäre.

Wolfgang Leininger

365

Die neue Gefahrstoffkennzeichnung  

Microsoft Academic Search

\\u000a Die EG-Verordnung 1272\\/2008 über die Einstufung, Kennzeichnung und Verpackung von Stoffen und Gemischen baut auf dem bestehenden\\u000a Chemikalienrecht auf und führt ein neues System zur Einstufung und Kennzeichnung gefährlicher Stoffe und Gemische ein, indem\\u000a die vom Wirtschaftsund Sozialrat der Vereinten Nationen (UN-ECOSOC) vereinbarten internationalen Kriterien für die Einstufung\\u000a und Kennzeichnung von gefährlichen Stoffen und Gemischen, das so genannte Globally Harmonized

Heinz Meinholz; Gabi Förtsch

366

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

367

Es lebe die Unverfrorenheit !\\  

Microsoft Academic Search

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

Domenico Giulini

368

Die Feldenkrais-Methode  

Microsoft Academic Search

Die Feldenkrais-Methode stellt einerseits eine körperorientierte Lernmethode dar, durch die Erkenntnisse über den eigenen\\u000a Körper und eigene dysfunktionale Bewegungsmuster zu gewinnen sind. Andererseits ist sie eine spezielle Form der Körpertherapie,\\u000a die auf der Basis verschiedenster Quellen und ganz wesentlich auch des Judo eine ganz eigene Behandlungsmethode generierte.

Hans-Erich Czetczok

369

Energiebereitstellung für die Elektromobilität  

Microsoft Academic Search

f€ u eine emissionsarme und nachhaltige Mobilit€ bieten, die aus regenerativen Quellen wie Wind- oder Solarenergie gespeist werden. Im Bereich des Fernverkehrs sind rein elektrische Antriebssysteme derzeit technologisch noch nicht reif. Batterietechnologien f€ die Schnellladung im Bereich von 5 bis 10 Minuten sind nur im Labor verf€ Die hohen Ladestr€ im Bereich bis zu einem Kiloampere stellen technologische Herausforderungen f€

Günther Brauner

2009-01-01

370

Untersuchungen über die Phototaxis  

Microsoft Academic Search

1.An drei grünen und einem farblosen lichtempfindlichen Protisten werden die absoluten Schwellenwerte für verschiedene Linien des Quecksilberspektrums ermittelt. Zur Verwendung gelangen die Wellenlängen 366 µµ (ultraviolett), 405 µµ (violett), 436 µµ (blau), 492 µµ (blaugrün), 546 µµ (gelbgrün) und 578 µµ (gelb), außerdem rotes Licht von 650 µµ aufwärts, für welches ein Osrampunktbrenner verwendet wird. Die Intensität des Lichtes wird

A. Luntz

1931-01-01

371

Thin die bonding techniques  

Microsoft Academic Search

Picking and bonding 50-micron thick chips presents new challenges to the die bonder industry. Extensive development efforts have identified a number of process challenges and solutions. This paper summarizes Esec's most recent learning's pertaining to the thin die bonding process. Problems with standard die bonding chip pick up and epoxy-dispensing techniques are discussed and solutions identified. Two novel pick solutions

J. Medding; R. Stalder; M. Niederhauser; P. Stoessel

2004-01-01

372

Two from One Casting. Art Education: 6681.20.  

ERIC Educational Resources Information Center

Two From One Casting is a studio course dealing with exploratory applications of casting methods and materials for students in grades 7 through 12 who wish to make permanent those creations easily destroyed by time or negligence. Course rationale, enrollment guidelines, objectives, outline of content, descriptions of activities and procedures,…

Hilf, Anne

373

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

374

MOLDS FOR CASTING PLUTONIUM  

DOEpatents

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

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

1962-02-27

375

Method of casting aerogels  

DOEpatents

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

Poco, J.F.

1993-09-07

376

Aluminum Fluidity in Casting  

NASA Astrophysics Data System (ADS)

The understanding and control of fluidity is, and has been, a major aspect of foundry technology development. This paper reviews the progress made in this area over the years as it applies to aluminum castings. As a result of this development, thin-wall, high-integrity aluminum castings which were previously not thought possible have been produced. Further work in this area is expected to allow metal-matrix composites to fulfill their technical and economic promise.

Mollard, Francois R.; Flemings, Merton C.; Niyama, Eisuke F.

1987-11-01

377

Casting critical components  

NASA Astrophysics Data System (ADS)

Investment casting is an essential processing route for critical rotating and static aero gas turbine components and for a wide spectrum of high integrity parts. These must perform reliably under arduous operating conditions involving high stresses and, frequently, extremely hostile environments. The advanced technology, in-process controls, rigorous specifications, and stringent testing and inspection procedures required for high integrity investment castings are considered along with some examples of the technological 'spin-off' into diverse industry sectors.

McCallum, R.

1982-06-01

378

An application of differential thermal analysis to determine the change in thermal properties of mold powders used in continuous casting of steel slabs  

Microsoft Academic Search

In continuous casting of steel slabs, all the processing steps have as their objective the attainment of the best superficial quality. The selection of an optimized mold powder is an important goal in attaining the best operating conditions. Therefore, the study of the main thermal properties of this raw material, which regulates the heat transfer between the steel plate and

R. W Soares; M. V. A Fonseca; R Neuman; V. J Menezes; A. O Lavinas; J Dweck

1998-01-01

379

Cheminformatics Analysis of EPA ToxCast Chemical Libraries to Identify Domains of Applicability for Predictive Toxicity Models and Prioritize Compounds for Toxicity Testing  

EPA Science Inventory

An important goal of toxicology research is the development of robust methods that use in vitro and chemical structure information to predict in vivo toxicity endpoints. The US EPA ToxCast program is addressing this goal using ~600 in vitro assays to create bioactivity profiles o...

380

Neutron radiography inspection of investment castings.  

PubMed

Investment casting, also known as the lost wax process, is a manufacturing method employed to produce near net shape metal articles. Traditionally, investment casting has been used to produce structural titanium castings for aero-engine applications with wall thickness less than 1 in (2.54 cm). Recently, airframe manufacturers have been exploring the use of titanium investment casting to replace components traditionally produced from forgings. Use of titanium investment castings for these applications reduces weight, cost, lead time, and part count. Recently, the investment casting process has been selected to produce fracture critical structural titanium airframe components. These airframe components have pushed the traditional inspection techniques to their physical limits due to cross sections on the order of 3 in (7.6 cm). To overcome these inspection limitations, a process incorporating neutron radiography (n-ray) has been developed. In this process, the facecoat of the investment casting mold material contains a cocalcined mixture of yttrium oxide and gadolinium oxide. The presence of the gadolinium oxide, allows for neutron radiographic imaging (and eventual removal and repair) of mold facecoat inclusions that remain within these thick cross sectional castings. Probability of detection (POD) studies have shown a 3 x improvement of detecting a 0.050 x 0.007 in2 (1.270 x 0.178 mm2) inclusion of this cocalcined material using n-ray techniques when compared to the POD using traditional X-ray techniques. Further, it has been shown that this n-ray compatible mold facecoat material produces titanium castings of equal metallurgical quality when compared to the traditional materials. Since investment castings can be very large and heavy, the neutron radiography facilities at the University of California, Davis McClellan Nuclear Radiation Center (UCD/MNRC) were used to develop the inspection techniques. The UCD/MNRC has very unique facilities that can handle large parts up to 39 ft (12 m) in length and 13 ft (4 m) high weighing up to 5000 lbs (2300 kg). These handling systems are robotically driven. The neutron radiographic system consists of a highly thermalized neutron beam. The neutron beam has an intensity of 5.6 x 10(6) n/cm2 s, with a L/D = 200 at a power of 2 MW. A divergent beam collimator is used which provides a beam of approximately 22 in (56 cm) in diameter at the film plane. A vacuum cassette with a gadolinium vapor deposited screen is used to collect the image. Exposure times can be as short as 3 min, or up to 30 min. PMID:15246417

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

2004-10-01

381

HIGH PRESSURE DIES  

DOEpatents

A press was invented for subjecting specimens of bismuth, urania, yttria, or thoria to high pressures and temperatures. The press comprises die parts enclosing a space in which is placed an electric heater thermally insulated from the die parts so as not to damage them by heat. The die parts comprise two opposed inner frustoconical parts and an outer part having a double frustoconical recess receiving the inner parts. The die space decreases in size as the inner die parts move toward one another against the outer part and the inner parts, though very hard, do not fracture because of the mode of support provided by the outer part.

Wilson, W.B.

1960-05-31

382

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

383

Spray casting project final report  

SciTech Connect

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

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

1996-08-01

384

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

2013-04-26

385

Nonstandard technique for the manufacture of specimens for mechanical testing of aluminum cast alloys  

Microsoft Academic Search

To carry out testing of mechanical properties of cast aluminum alloys, the description of a nonstandard technique for preparation\\u000a of cast samples is presented. Recently, cast samples have found increasing application in machine building. However, by their\\u000a mechanical properties, they do not correspond to samples turned from a cast metal of the same alloy. Moreover, their characteristics\\u000a are strongly affected

S. V. Savchenko; A. V. Koltyguin

2007-01-01

386

Burnishability of a nickel and a cobalt base casting alloys.  

PubMed

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

Nasr, H H; Mosleh, I

1989-10-01

387

Die Stacking (3D) Microarchitecture  

Microsoft Academic Search

D die stacking is an exciting new technology that in- creases transistor density by vertically integrating two or more die with a dense, high-speed interface. The result of 3D die stacking is a significant reduction of interconnect both within a die and across dies in a system. For instance, blocks within a microprocessor can be placed vertically on multiple die

Bryan Black; Murali Annavaram; Ned Brekelbaum; John Devale; Lei Jiang; Gabriel H. Loh; Don McCauley; Pat Morrow; Donald W. Nelson; Daniel Pantuso; Paul Reed; Jeff Rupley; Sadasivan Shankar; John Paul Shen; Clair Webb

2006-01-01

388

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

389

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

390

Einführung in die Biotechnologie  

Microsoft Academic Search

\\u000a Biotechnologie wird mit vielen Eigenschaften belegt: sie wird als ’Schlüsseltechnologie’ (RooBEEK 1995), ’Querschnittstechnologie’\\u000a (REIB und KOSCHATZKY 1997), ’wissensbasierte Technologie’ und als eine der wichtigsten Technologien des 21. Jahrhunderts’\\u000a (GRuPP 1995) bezeichnet. Die Hysterie, die beim Börsengang junger Biotechnologieunternehmen insbesondere in den 1980er Jahren\\u000a in den USA zu beobachten war, die Hoffnungen auf immense Unternehmensgewinne, Durchbrüche kommerzieller Anwendungen und die\\u000a Schaffung

Viola Peter

391

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

NASA Astrophysics Data System (ADS)

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 ˜1.7 pct for the gravity die cast LM25 alloy to ˜8.0 pct for the direct squeeze cast LM25 alloy in the T6 heat-treated condition. 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 ˜6.5 pct, compared to that of ˜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.

1999-05-01

392

Slip casting under pressure  

NASA Astrophysics Data System (ADS)

The addition of a pressure during slip casting increases the rate of material deposition and enables larger pieces to be fabricated. In this study, this process has been further developed using monolithic Al2O3 and Al2O3-SiC composites. Slip casting formulations based on both dispersed and coagulated slurries have been analyzed. Excellent results are achieved using coagulated slurries, with no cracking present after drying. The effect of pressure is to increase the green density with a consequent increase in the fired density. In addition, homogeneous microstructures are achieved in the composite system, despite the large difference in particle size used.

Grazzini, H. H.; Wilkinson, D. S.

1992-08-01

393

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

394

Aluminum Castings for Anodic Oxidation.  

National Technical Information Service (NTIS)

The significance of the manufacture of decorative anodically oxidized aluminum castings is demonstrated by means of examples, and alloys suitable for this are enumerated. Then dealt with are errors of casting and melting technique which become apparent wi...

A. A. Bloch

1966-01-01

395

Investment Casting of Columbium Alloys.  

National Technical Information Service (NTIS)

The state of the art of columbium alloy investment castings has been advanced. In addition to demonstration of castability of four different alloys, the cast material itself has been characterized with respect to microstructure, alloy segregation, weldabi...

J. R. Humphrey A. I. Niravath

1975-01-01

396

Investment casting of gold jewellery  

Microsoft Academic Search

Changes in temperature which take place during pouring of a melt and flow into the mould vary greatly, and also depend on\\u000a the casting technique used. Understanding these changes is important for optimum casting practice.

Dieter Ott; Christoph J. Raub

1986-01-01

397

Advances in nickel-based cast superalloys  

Microsoft Academic Search

Nickel-based superalloys have served as the most competitive high temperature structural materials under highly stressed and\\u000a aggressive operating conditions in a variety of applications for more than 60 years. The most demanding among all the applications\\u000a has been the gas turbine aerofoil castings of modern aero-engines. These turbine parts operate in extremely aggressive environment\\u000a of high velocity hot combustion gas-air

Niranjan Das

2010-01-01

398

When Somebody Dies  

MedlinePLUS

... dies. It is just as if a glass bottle full of water broke, and the bottle became useless. The container is gone, but what's ... hole in our lives. Maybe you had a pet that died. Remember the first few times you ...

399

Shame, Death, and Dying  

Microsoft Academic Search

This paper deals with the influence of shame on the way in which Western society, particularly North America, is coping with death and dying. From being a familiar event, death and dying have become a shameful aspect of life. Thus, this paper provides some understanding of this important transformation, and it challenges some of our present attitudes regarding death and

Ramón Martínez de Pisón Liébanas

2002-01-01

400

Choosing when to Die  

Microsoft Academic Search

What would make it the right time for you to die, or the wrong one? In particular, could it be the right time for you to die even if your loved ones want to make the sacrifices needed to prolong your life, because that would cost them too dearly? The worry is that it would be selfish to permit these

Norvin Richards

2005-01-01

401

The fractography of casting alloys  

Microsoft Academic Search

Several types of casting alloys were fractured using various loading modes (uniaxial tension, bending, impact, and torsion, and cyclic stressing), and the corresponding mechanical properties were determined. The unetched and etched fracture surfaces and the microstructures were examined using conventional techniques. The types of casting alloys that were the subjects f these investigations include gray iron, ductile iron, cast steel,

G POWELL

1994-01-01

402

Thermal investigation of compound cast steel tools  

Microsoft Academic Search

Tools for hot forging are exposed to complex stresses during their life-cycle. Therefore, forging dies should have a high wear resistance and toughness on the surface, combined with excellent thermal conductivity in the die body. Hot-work tool steel is appropriate for this application except from its thermal conductance. Hence, a tool consisting of hot-work tool steel in the area of

Mirko Schaper; Heinz Haferkamp; Matthias Niemeyer; Christoph Pelz; Roman Viets

1999-01-01

403

Casting and Angling.  

ERIC Educational Resources Information Center

|As part of a series of books and pamphlets on outdoor education, this manual consists of easy-to-follow instructions for fishing activities dealing with casting and angling. The manual may be used as a part of the regular physical education program in schools and colleges or as a club activity for the accomplished weekend fisherman or the…

Smith, Julian W.

404

Nickel based casting alloy  

Microsoft Academic Search

A nickel base casting alloy containing 10 to 25 percent chromium, 3 to 8 percent manganese, 3 to 10 percent niobium, 0 to 3.5 percent aluminum, 0.5 to 2.0 percent beryllium which exhibits lower melting characteristics allowing enhanced compatibility to gypsum bonded investments.

A. P. Burnett; W. C. Bollinger

1985-01-01

405

Casting the Untrained Actor.  

ERIC Educational Resources Information Center

Discusses the arduous task of casting and directing untrained middle and secondary school actors in terms of auditioning, getting started, planning for the first meeting, focusing on the obvious, rehearsing, learning the lines, becoming the character, running work-through rehearsals, and doing run-throughs and performances. Notes not to forget to…

Bogar, Thomas A.

2000-01-01

406

Clad Cast Steel Strip.  

National Technical Information Service (NTIS)

A process for producing continuous cast hot band crystalline metal strips comprising feeding thin gauge metal strips and molten metal into a gap formed between opposed quenching surfaces. The film of molten metal is cooled while in contact with the quench...

R. L. Sheneman

1983-01-01

407

Analogy Between Heat and Mass Transfer for Constant-Rate Period During Non-Convective Drying: Application to Water-Based Alumina Suspension for Tape Casting  

NASA Astrophysics Data System (ADS)

Analogy between heat and mass transfer is proposed for the constant-rate period during non-convective drying process. The analogy is applied to predict a temperature-dependent heat-transfer coefficient from a temperature-dependent mass-transfer coefficient also presented for the constant-rate period during non-convective drying of water-based alumina suspension for tape casting. Predicted values of the temperature-dependent heat and mass transfer coefficients are compared with experimental data and good agreement is obtained.

Puyate, Y. T.

408

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

Microsoft Academic Search

Hydrogels obtained from lower toxicity monomers of N-(hydroxymethyl)acrylamide and N,N?-methylenebisacrylamide were applied to form nonstoichiometric CaZrO3-based electrolytes. A coprecipitation-calcination method with ((NH4)2C2O4) in concentrated NH3 aqueous solution was used to synthesise CaZrO3 involving 51mol.% CaO (CZ-51) powder. The gas-tight CaZrO3-based rods were prepared by the gel-casting method with 45vol.% suspension and then sintered at 1500°C–2h. It was found that in

Magdalena Dudek

2009-01-01

409

Computer cast blast modelling  

SciTech Connect

Cast blasting can be designed to utilize explosive energy effectively and economically for coal mining operations to remove overburden material. The more overburden removed by explosives, the less blasted material there is left to be transported with mechanical equipment, such as draglines and trucks. In order to optimize the percentage of rock that is cast, a higher powder factor than normal is required plus an initiation technique designed to produce a much greater degree of horizontal muck movement. This paper compares two blast models known as DMC (Distinct Motion Code) and SABREX (Scientific Approach to Breaking Rock with Explosives). DMC, applies discrete spherical elements interacted with the flow of explosive gases and the explicit time integration to track particle motion resulting from a blast. The input to this model includes multi-layer rock properties, and both loading geometry and explosives equation-of-state parameters. It enables the user to have a wide range of control over drill pattern and explosive loading design parameters. SABREX assumes that heave process is controlled by the explosive gases which determines the velocity and time of initial movement of blocks within the burden, and then tracks the motion of the blocks until they come to a rest. In order to reduce computing time, the in-flight collisions of blocks are not considered and the motion of the first row is made to limit the motion of subsequent rows. Although modelling a blast is a complex task, the DMC can perform a blast simulation in 0.5 hours on the SUN SPARCstation 10--41 while the new SABREX 3.5 produces results of a cast blast in ten seconds on a 486-PC computer. Predicted percentage of cast and face velocities from both computer codes compare well with the measured results from a full scale cast blast.

Chung, S. [ICI Explosives Canada, North York, ON (Canada); McGill, M. [ICI Explosives USA, Dallas, TX (United States); Preece, D.S. [Sandia National Labs., Albuquerque, NM (United States)

1994-07-01

410

Improvement in Mechanical Properties of A356 Tensile Test Bars Cast in a Permanent Mold by Application of a Knife Ingate  

NASA Astrophysics Data System (ADS)

As a standard test-bar permanent mold, the "Stahl" Mold has been widely used in foundries to assess the properties of cast alloys. However, inferior mechanical properties are often obtained with this mold due to shrinkage-induced microporosity in the gage section. In order to improve the mechanical properties, a design modification comprising a thin knife ingate between the feeder and test-bar cavity was evaluated in this work. The new design was studied by computer-aided simulation. Simulations predicted that the knife ingate improved the metal feeding capability and reduced the shrinkage microporosity at the gage section from 3 to 1 pct. Experimental verification work has been undertaken with aluminum alloy A356, and the results were analyzed by a statistics theory-based factorial analysis method. The new design resulted in main effects with ultimate tensile strength (UTS) improvement of 20 MPa (relative 12 pct) and elongation increment of 2 pct (relative 45 pct) for the as-cast test bars.

Wang, Yaou; Schwam, David; Neff, David V.; Chen, Chai-Jung; Zhu, Xuejun

2012-03-01

411

Glaze for ceramic superplastic forming (SPF) dies  

US Patent & Trademark Office Database

The life of ceramic SPF dies can be enhanced significantly by plasma spray application of a cordierite glaze on the forming surface. The preferred glaze has a coefficient of thermal expansion close to or matching with the ceramic of the die, and, typically, is a 2.cndot.2.cndot.5 MAS system including 2-10 mol % TiO.sub.2 (or above 8 wt %).

Sanders; Daniel G. (Sumner, WA); Peterson; Martin A. (Puyallup, WA); Van Aken; David C. (Rolla, MO); Weaver; D. Trent (Rolla, MO); Miller; F. Scott (Rolla, MO); Smith; Jeffrey D. (Rolla, MO)

2004-02-17

412

Numerical simulation of displacement field of solidification process for investment casting  

Microsoft Academic Search

Computer simulation of the solidification process is used widely in the design of the mould and the die configuration. In this work, a simple and efficient methodology is proposed for the numerical simulation of displacement field for investment casting. The heat-transfer behavior and the time-dependent heat transfer coefficient between a casting and mould are investigated by inverse heat-conduction analysis, so

Yiwei Dong; Kun Bu; Dinghua Zhang

2008-01-01

413

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

414

Micromechanical modeling of ductile cast iron incorporating damage. Part I: Ferritic ductile cast iron  

Microsoft Academic Search

The market for ductile cast iron as a substitute material increases every year. The material structural performance is strongly dependent on the microstructure. Micromechanics can help in understanding the role played by the microstructure constituents as well as the effects associated to the shape of the spheroids, their density, surface roughness, etc. The potential of application for micromechanics modeling can

Nicola Bonora; Andrew Ruggiero

2005-01-01

415

When a Pet Dies  

MedlinePLUS

... losses throughout life. Sharing the News and the Grief One of the most difficult parts about losing ... Died. How Can I Feel Better? Death and Grief Pets and Your Health Contact Us Print Additional ...

416

Die andere Revolution  

NASA Astrophysics Data System (ADS)

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

Kippenhahn, Rudolf

2005-05-01

417

On finishing of pressing die surfaces using machine hammer peening  

Microsoft Academic Search

Machine hammer peening (MHP) is a new method for finishing of surfaces. With this method, the workpiece surface is hammered\\u000a with a spherical carbide tool. The main objective of the study was to evaluate whether the MHP method could become a plausible\\u000a substitute for manual polishing in pressing die manufacturing where nodular cast iron is a common workpiece material. To

Johan Berglund; Magnus Liljengren; Bengt-Göran Rosén

2011-01-01

418

Volume MLS ray casting.  

PubMed

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

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

419

USGS CoreCast  

NSDL National Science Digital Library

Just about everyone seems to be creating a podcast these days, and a number of government agencies have entered the fray as of late. The United States Geological Survey recently decided to hang out their own podcast shingle, and the results of their labors can be explored here. The site states that their "CoreCast" is "natural science from the inside out", which seems like an appropriate label. The podcasts range in length from two to fifteen minutes, and they cover topics such as polar bear research, sex-changing fish, and climate change. One podcast that shouldn't be overlooked is "This Episode of CoreCast is Highly Questionable". In a mere three minutes, host Scott Horvath responds to a number of questions in an engaging fashion. After listening to an episode or two, visitors will probably want to sign up to receive email updates about new episodes.

420

Die Macht der Ideen  

Microsoft Academic Search

\\u000a 1925 veröffentlichte Karl Mannheim den späterhin berühmt gewordenen programmatischen Aufsatz Das Problem einer Soziologie des Wissens.1 Aus guten Gründen wurde der Text in erster Linie als Ausformulierung einer „Soziologie des Wissens“ gewürdigt, deren Eigenständigkeit\\u000a und Herausforderungspotential zahlreiche Intellektuelle sofort erkannten.2 Entsprechend heftig fielen die zahlreichen Reaktionen auf Mannheims neuartige Soziologie aus, die sich nichts weniger vorgenommene\\u000a hatte als angeben zu

Thomas Meyer

421

Advanced Cast Austenitic Stainless Steels for High Temperature Components  

SciTech Connect

In July of 2002, a Cooperative Research and Development Agreement (CRADA) was undertaken between Oak Ridge National Laboratory (ORNL) and Caterpillar, Inc. (Caterpillar Technical Center) to develop and commercialize new cast stainless steels invented and initially tested on a prior CRADA. This CRADA is a direct follow-on project to CRADA ORNL-99-0533 for diesel engine exhaust component and gas turbine engine structural component applications. The goal of this new CRADA was to develop and commercialize the newly discovered cast stainless steels (primarily CF8C-Plus) with improved performance and reliability, as lower-cost upgrade alternatives to more costly cast Ni-based superalloys.

Maziasz, P.J.; Shingledecker, J.P.; Evans, N.D.; Pollard, M.J. (Caterpillar, Inc.)

2008-10-09

422

Cast Tenzaloy aluminum optics  

NASA Astrophysics Data System (ADS)

Since the early sixties, cast aluminum optics has held out a promise of low cost, durability, lightweight, ease of manufacture, the possibility of welding together sections to form large optics and a good match of some astronomical programs such as photometry. Needless to say, this rosy future has been fraught with difficulties. Poor short-term stability, sensitivity to temperature, porosity, bimetallic warping, soft optical surface, poor specularity, nickel adhesion problems, poor image quality, and the inability to generate aspherics, have all contributed to the bad name cast aluminum optics has acquired over the years. With the advent of improved aluminum alloys, long-term dimensional stability data, advances in adaptive optics and the need for very large monolithic mirrors with a relatively low handling risk, aluminum optics deserve another look. This paper is a collection of some of the early attempts to build cast aluminum mirrors using the stable alloy, Tenzaloy. The results of those efforts are discussed together with recommendations for future aluminum metal mirror work.

Forbes, Fred F.

1993-10-01

423

Fabrication and Performance of Ni-YSZ Anode Supported Cell for Coal Derived Syngas Application by Tape Casting and Spin Coating  

SciTech Connect

Ni-YSZ anode supported cell has been developed for direct utilization of coal derived syngas as fuel in the temperature range of 700-850° C. The porous Ni-YSZ anode substrate was prepared based on processes of slip casting and lamination of anode tape. Then thin-film YSZ electrolyte was deposited on pre-sintered anode substrate via a colloidal spin coating technique and an optimized final sintering route. Dense and crackfree YSZ electrolyte was successfully obtained after sintering at 1440C for 4hrs. Processing factors like pre-sintering of anode, solvent, coating cycles and sintering route on the final properties of YSZ film was studied. A power density of 0.62W/cm2 has been achieved for the anode supported cell tested in 97%H2/3%H2O at 800°C. EIS test results indicated the cell performance was essentially influenced by interfacial resistance and charge transfer process.

Gong, Mingyang (West Virginia U., Morgantown WV); Jiang, Yinglu (West Virginia U., Morgantown WV); Johnson, C.D.; Xingbo, Liu (West Virginia U., Morgantown WV)

2007-10-01

424

Slip casting of partially stabilized zirconia  

Microsoft Academic Search

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

H. Taguchi; H. Miyamoto; Y. Takahashi

1985-01-01

425

INVESTMENT CASTING OF ALLVAC® 718PLUS™ ALLOY  

Microsoft Academic Search

Many jet engine structural components are fabricated using investment castings, generally a lower-cost material alternative to built-up structures. Waspaloy is a nickel-base, age-hardenable superalloy with excellent high-temperature strength and good oxidation resistance, utilized in rotating aero engine components up to 704°C and higher temperatures for static components in modern jet engines. Typical applications include casings, frames and rings. Waspaloy has

T. D. Bayha; M. Lu; K. E. Kloske

426

Metallographic Characterization of Hypoeutectic Martensitic White Cast Irons  

Microsoft Academic Search

High wear resistance and low cost are among the most appreciated properties for the non-alloyed white cast irons. Their toughness levels, however, are poor. An attempt to optimize the compromise between abrasive wear resistance and impact toughness could be reached through the use of low-alloy Ni-Hard cast irons satisfying the majority of mining applications in mineral crushing, classification, and transportation.

J. A. Pero-Sanz; D. Plaza; J. I. Verdeja; J. Asensio

1999-01-01

427

Tape casting of non-aqueous silicon nitride slips  

Microsoft Academic Search

Tape casting is a powerful method for the manufacturing of flat, large area ceramic components. Silicon nitride is a reference material for high temperature structural applications. Between them, thick film\\/coating technologies and ceramic–ceramic joining are receiving an increased attention. In this work, the rheological behavior on non-aqueous silicon nitride slips for tape casting was investigated considering different solvent and binding

C. A Gutiérrez; R Moreno

2000-01-01

428

Using cold-crucible melting for titanium precision castings  

Microsoft Academic Search

Titanium precision castings have not kept pace with technical design requirements for demanding applications, such as the\\u000a aerospace industry; advances in increased size capability have been offset by a lack of advances in metallurgical integrity\\u000a and dimensional tolerances. Hence, there is a strong need for improvement in the casting process. Taramm has developed a process\\u000a that combines cold-crucible induction melting

Georges Broihanne; John Bannister

2000-01-01

429

Die Europäische Union, die Europäische Gemeinschaft und ihre Rechtsordnung, die Europäische Lebensmittelkontrolle  

NASA Astrophysics Data System (ADS)

Die Europäische Union (EU) ist ein Zusammenschluss von siebenundzwanzig unabhängigen Staaten, um deren wirtschaftliche, politische und soziale Zusammenarbeit zu verstärken. Seit 1. Mai 2007 hat sie die folgenden Mitglieder: Österreich, Belgien, Bulgarien, Dänemark, Finnland, Frankreich, Deutschland, Griechenland, Irland, Italien, Luxemburg, die Niederlande, Portugal, Spanien, Schweden, das Vereinigte Königreich von Großbritannien und Nordirland, Zypern, die Tschechische Republik, Estland, Ungarn, Lettland, Litauen, Malta, Polen, Rumänien, die Slowakei und Slowenien [1]. (Hinweis: Die Republik Zypern hat juristisch Souveränität über die ganze Insel, da die Türkische Republik Nordzypern international nicht anerkannt wird.)

Gallhoff, Gudrun; Rimkus, Gerhard G.

430

Modeling of alloy casting solidification  

NASA Astrophysics Data System (ADS)

Alloy casting solidification processes involve many physical phenomena such as chemistry variation, phase transformation, heat transfer, fluid flow, microstructure evolution, and mechanical stress.1 Simulation technologies are applied extensively in casting industries to understand the effects of these phenomena on the formation of defects and on the final mechanical properties of the castings. As of today, defect prediction is still one of the main purposes for casting solidification simulation. In this paper, we will first present the commonly used microstructure simulation methods, then discuss the predictions of the major defects of a casting, such as porosity, hot tearing, and macrosegregation. The modeling of casting solidification can be chained with later stages of heat treatment such that the resultant microstructure, defects, and mechanical state will be used as the initial conditions of the subsequent processes, ensuring the tracking of the component history and maintaining a high level of accuracy across metallurgical stages.

Guo, Jianzheng; Samonds, Mark

2011-07-01

431

LOST FOAM CASTING OF MAGNESIUM ALLOYS  

SciTech Connect

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

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

2007-01-01

432

Testing High-Reliability Software for Continuous Casting Steel Plants - Experiences and Lessons Learned from Siemens VAI  

Microsoft Academic Search

As the world's leading supplier of metallurgical plants, Siemens VAI provides integrated and universally applicable continuous casting systems for the steel industry. The complexity of the process of casting liquid steel is supported by software products that enable high-quality steel casts and efficient plant performance. Over the last recent years Siemens VAI developed a flexible software product line. The system

Stefan Larndorfer; Rudolf Ramler; Christian Federspiel; Klaus Lehner

2007-01-01

433

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

Microsoft Academic Search

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

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

2003-01-01

434

Steel casting by diffusion solidification  

Microsoft Academic Search

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

George Langford; Robert E. Cunningham

1978-01-01

435

Steel casting by diffusion solidification  

Microsoft Academic Search

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

George Langford; Robert E. Cunningham

1978-01-01

436

The Caste-Class Association in India  

Microsoft Academic Search

This paper empirically analyzes the association between caste and class in India. I find a tentative congruence between castes and classes at the extremes of the caste system and a slight weakening in this association over time. Although Scheduled Castes have low upward mobility, higher castes are not entirely protected from downward mobility.

Divya Vaid

2012-01-01

437

STME T\\/C casting technology  

Microsoft Academic Search

The T\\/C casting technology developed by the National Launch System for the Space Transportation Main Engine is described. Special attention is given to the selection of JBK-75 as the combustion chamber casting alloy, some unique casting issues, and the development castings which were produced. Current plans call for producing a 650K full cast jacket mockup in the 4500 pound furnace.

J. R. Lobitz; P. C. Ackerman; S. L. Weber

1992-01-01

438

Columnar to equiaxed transition in high Cr white iron castings  

SciTech Connect

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

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

1996-07-15

439

A new freeze casting technique for ceramics  

NASA Astrophysics Data System (ADS)

A new freeze casting technique for ceramics capable of manufacturing near room temperature with a sublimable vehicle has been developed in order to eliminate expensive processes under extremely cold temperatures in the conventional freeze casting. Fluid concentrated slurries of Al2O 3 powder in molten camphene (C10H16) were successfully prepared at 55°C with a small amount of a dispersant. These slurries were quickly solidified (frozen) at room temperature to yield a rigid solid green body, where the frozen camphene was easily removed by sublimation (freeze-drying) with negligible shrinkage. Sintering was successfully conducted without any special binder burnout process to yield dense sintered bodies (over 98% T.D). An organic alloy with a eutectic composition in the naphthalene (C 10H8)-camphor (C10H16O) binary system with a eutectic temperature of 31°C was also found to be a successful vehicle for the new ceramic freeze casting. The fabrication processes are almost the same as those with camphene. It was found that vehicles with off-eutectic compositions resulted in large voids in the sintered body due to the ceramic particle rejection by pro-eutectic crystals during freezing. At the eutectic composition, fine lamellar microstructure in the solidified vehicle inhibits the particle rejection. The proposed advantages of the new freeze casting technique with a sublimable vehicle include; (1) elimination of extremely cold temperatures used in conventional freeze casting; (2) elimination of troublesome binder burnout process; and (3) fast manufacturing cycle due to quick solidification. Porous ceramic bodies with unique interconnected pore channels were fabricated by the new freeze casting with lower solid content. The unique channels surrounded by fully dense walls have nearly circular cross-sections unlike conventional aqueous freeze casting. The porosity and the channel diameters are controllable by the solid content in the slurry. The unique channels are replicas of entangled dendrites of frozen camphene, which sublimes during freeze-drying process. The unique porous structure with interconnected pore channels, which is completely new, is considered potentially useful in many applications such as filters and implantable bone scaffolds.

Araki, Kiyoshi

440

COMPARISON OF FATIGUE BEHAVIOR FOR CENTRIFUGALLY CAST AND KEEL BLOCK CAST STEEL  

Microsoft Academic Search

The objective of this research was to determine if location through the wall thickness of centrifugal castings affects fatigue properties and to compare fatigue and monotonic tensile properties of centrifugal castings to statically cast keel block castings. Specimens were machined from centrifugal and keel block AISI 8630 steel castings. Centrifugal casting specimens were taken from three different locations (outer, middle

J. J. Gradman; R. I. Stephens; R. A. Hardin; C. Beckermann

441

High Strength Aluminum Casting Technology: Squeeze Casting of 7075 Alloy.  

National Technical Information Service (NTIS)

The objective of this investigation was to develop wrought 7075-T6 mechanical properties in a cast aluminum alloy component of net or near-net shape. A squeeze casting process was selected as the manufacturing process. Following a limited heat treatment o...

J. R. Thompson

1977-01-01

442

A New Method For Advanced Virtual Design Of Stamping Tools For Automotive Industry: Application To Nodular Cast Iron EN-GJS-600-3  

NASA Astrophysics Data System (ADS)

This contribution presents an approach combining the stamping numerical processing simulations and structure analysis in order to improve the design for optimizing the tool fatigue life. The method consists in simulating the stamping process via AutoForm® (or any FEM Code) by considering the tool as a perfect rigid body. The estimated contact pressure is then used as boundary condition for FEM structure loading analysis. The result of this analysis is used for life prediction of the tool using S-N fatigue curve. If the prescribed tool life requirements are not satisfied, then the critical region of the tool is redesigned and the whole simulation procedures are reactivated. This optimization method is applied for a cast iron EN-GJS-600-3 as candidate stamping tool materiel. The room temperature fatigue S-N curves of this alloy are established in laboratory under uniaxial push/pull cyclic experiments on cylindrical specimens under a load ratio of R (?min/?max) = -2.

Ben-Slima, Khalil; Penazzi, Luc; Mabru, Catherine; Ronde-Oustau, François; Rezaï-Aria, Farhad

2011-05-01

443

Effect of microstructure on the mechanical properties of as-cast Ti-Nb-Al-Cu-Ni alloys for biomedical application.  

PubMed

The correlation between the microstructure and mechanical behavior during tensile loading of Ti68.8Nb13.6Al6.5Cu6Ni5.1 and Ti71.8Nb14.1Al6.7Cu4Ni3.4 alloys was investigated. The present alloys were prepared by the non-equilibrium processing applying relatively high cooling rates. The microstructure consists of a dendritic bcc ?-Ti solid solution and fine intermetallic precipitates in the interdendritic region. The volume fraction of the intermetallic phases decreases significantly with slightly decreasing the Cu and Ni content. Consequently, the fracture mechanism in tension changes from cleavage to shear. This in turn strongly enhances the ductility of the alloy and as a result Ti71.8Nb14.1Al6.7Cu4Ni3.4 demonstrates a significant tensile ductility of about 14% combined with the high yield strength of above 820MPa already in the as-cast state. The results demonstrate that the control of precipitates can significantly enhance the ductility and yet maintaining the high strength and the low Young's modulus of these alloys. The achieved high bio performance (ratio of strength to Young's modulus) is comparable (or even superior) with that of the recently developed Ti-based biomedical alloys. PMID:24094189

Okulov, I V; Pauly, S; Kühn, U; Gargarella, P; Marr, T; Freudenberger, J; Schultz, L; Scharnweber, J; Oertel, C-G; Skrotzki, W; Eckert, J

2013-08-06

444

Investment Casting of Magnesium-Lithium Alloys.  

National Technical Information Service (NTIS)

A method was developed for investment casting magnesium-lithium alloys into inhibited gypsum-bonded molds. Both prototype castings and separately cast test bars (0.252 inch) were produced. Visual and metallographic examination showed no evidence of metal-...

A. Saia R. E. Edelman

1966-01-01

445

14 CFR 29.621 - Casting factors.  

Code of Federal Regulations, 2013 CFR

...of this section apply to structural castings except castings that are pressure tested as parts of hydraulic or other fluid systems and do not support structural loads. (b) Bearing stresses and surfaces. The casting factors specified in...

2013-01-01

446

14 CFR 27.621 - Casting factors.  

Code of Federal Regulations, 2013 CFR

...of this section apply to structural castings except castings that are pressure tested as parts of hydraulic or other fluid systems and do not support structural loads. (b) Bearing stresses and surfaces. The casting factors specified in...

2013-01-01

447

Improved Foundry Castings Utilizing CAD/CAM.  

National Technical Information Service (NTIS)

The CAD/Cam Casting process is being developed as an aid to casting engineers in designing better steel castings in a fraction of the time presently required. The computer routines incorporate drafting routines and computer assisted computations relative ...

T. Wassel J. Chevalier R. Nariman W. S. Hwang S. Miller

1981-01-01

448

Electroslag-Casting Process and Properties.  

National Technical Information Service (NTIS)

The electroslag-casting process is an extension of the electroslag-remelting process. The castings produced by this technique have the advantages of smooth defect-free finish, freedom from conventional casting defects, more reproducible mechanical propert...

V. K. Sikka

1986-01-01

449

Dying to Play.  

ERIC Educational Resources Information Center

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

Miller, John K.

1998-01-01

450

Die medizinische Habilitation  

Microsoft Academic Search

Zusammenfassung Fragestellung: Unter Bezugnahme auf den Wandel von Bildungs- und Gesellschaftsstrukturen ist in letzter Zeit auch die medizinische Habilitation als akademischer Qualifikationsnachweis in Frage gestellt worden. Vor diesem Hintergrund war das Ziel unserer Studie, ein aktuelle Meinungsbild erfolgreicher Habilitanden zu Habilitationsvoraussetzungen, Habilitationsverfahren und Stellenwert der Habilitation zu erhalten sowie potentielle Reformwünsche zu erfassen. Kollektiv und Methodik: Zielgruppe unserer Umfrage stellten

Andreas Weber; Elke Lindner; Dieter Weltle; Gerhard Lehnert

2000-01-01

451

Characterization of stacked die using die-to-wafer integration for high yield and throughput  

Microsoft Academic Search

We have developed a die-to-wafer integration technology for high yield and throughput for the formation of high bandwidth, high performance, and short-distance interconnections in three-dimensional (3D) stack applications. The results show that multiple 70-mum thick die can be successfully assembled in stacks on top of a wafer using a single bonding step, rather than by repeated sequential bonding steps. In

K. Sakuma; P. S. Andry; C. K. Tsang; K. Sueoka; Y. Oyama; C. Patel; B. Dang; S. L. Wright; B. C. Webb; E. Sprogis; R. Polastre; R. Horton; J. U. Knickerbocker

2008-01-01

452

Using solidification parameters to predict porosity distributions in alloy castings  

SciTech Connect

Quality criteria used in the computer-aided design and analysis of casting processes typically relate geometric, thermal, or solidification parameters to structural features such as centerline shrinkage and microporosity. Quality criteria for the prediction of porosity in castings have been used successfully in steel, but the application of criteria functions to nonferrous alloys has been less successful. This paper reports that recent work suggests that the dominating mechanism that determines the amount and distribution of porosity in castings is strongly dependent on the solidification mode of the alloy and the solidification conditions. Accordingly, casting processes and alloy types are divided into four groups and a different set of criteria functions are obtained for each group.

Viswanathan, S.; Sikka, V.K. (Oak Ridge National Lab., Oak Ridge, TN (United States)); Brody, H.D. (Univ. of Connecticut, CT (United States))

1992-09-01

453

Volatile species retention during metallic fuel casting  

NASA Astrophysics Data System (ADS)

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

Fielding, Randall S.; Porter, Douglas L.

2013-10-01

454

Education and Caste in India  

ERIC Educational Resources Information Center

This paper analyses the policy of reservation for lower castes in India. This policy is similar to that of affirmative action in the United States. The paper provides a brief overview of the caste system and discusses the types of groups that are eligible for reservation, based on data from government reports. The stance of this paper is that…

Chauhan, Chandra Pal Singh

2008-01-01

455

Education and caste in India  

Microsoft Academic Search

This paper analyses the policy of reservation for lower castes in India. This policy is similar to that of affirmative action in the United States. The paper provides a brief overview of the caste system and discusses the types of groups that are eligible for reservation, based on data from government reports. The stance of this paper is that affirmative

Chandra Pal Singh Chauhan

2008-01-01

456

Machine Casting of Ferrous Alloys.  

National Technical Information Service (NTIS)

Emphasis of the work is on development of a process or processes involving casting of semi-solid alloys. During the six month period of research covered by the report, emphasis was on developing casting systems which combine (1) a method of producing a se...

J. R. Melcher M. C. Flemings N. Matsumoto R. Mehrabian R. G. Riek

1974-01-01

457

Surface carburization of steel castings  

Microsoft Academic Search

Shaping methods based on sand-resin mixtures have undoubted benefits and accordingly are increas? ingly used in the manufacture of highperformance iron, steel, and nonferrousalloy castings. However, they cannot be unconditionally recommended for lowcarbon steel castings. This is because heat from the molten metal destroys the organic components present in such molds. At low temperatures (150 °C), these mixtures mainly emit

E. B. Ten; O. A. Kol’; I. B. Badmazhapova; M. P. Klyuev

2011-01-01

458

Lost-Soap Aluminum Casting.  

ERIC Educational Resources Information Center

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

Mihalow, Paula

1980-01-01

459

Electroslag component casting. [Nickel aluminide  

Microsoft Academic Search

This project is directed toward the development of electroslag-casting (ESC) technology for use in coal conversion components such as valve bodies, pump housings, and pipe fittings. The aim is also to develop a sufficient data base to permit electroslag casting to become an ASME Code-accepted process. It is also intended to transfer the ESC process technology to private industry. A

Sikka

1986-01-01

460

Lost-Soap Aluminum Casting.  

ERIC Educational Resources Information Center

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

Mihalow, Paula

1980-01-01

461

Casting Freedom, 1860-1862  

ERIC Educational Resources Information Center

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

Social Education, 2005

2005-01-01

462

Electroslag component casting. [Nickel aluminide  

SciTech Connect

This project is directed toward the development of electroslag-casting (ESC) technology for use in coal conversion components such as valve bodies, pump housings, and pipe fittings. The aim is also to develop a sufficient data base to permit electroslag casting to become an ASME Code-accepted process. It is also intended to transfer the ESC process technology to private industry. A total of 32 electroslag castings of 2.25Cr-1Mo, 9Cr-1Mo, type 316, and nickel aluminide were procured from four facilities for evaluation (Table 1). The most complex castings procured during this program were the valve bodies shown in Figure 2. The castings were subjected to various heat treatments (Table 2), checked for chemical composition uniformity from top to bottom, and subjected to macrostructural evaluation and mechanical properties testing. Results are discussed. 10 refs., 7 figs., 3 tabs.

Sikka, V.K.

1986-01-01

463

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

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

464

Die Bedeutung von User Generated Content für die Hotellerie  

Microsoft Academic Search

\\u000a Schlagwörter wie User Generated Content (UGC), Communities, Social Web und Web 2.0 beschäftigen die Tourismusbranche und haben\\u000a auch die Hotellerie bereits fest im Griff. Warum aber erfreut sich UGC im Tourismus so großer Beliebtheit? Handelt es sich\\u000a um einen Fluch oder einen Segen für die Hotellerie? Beeinflusst UGC die Anzahl der Buchungen einer Unterkunft und welche Möglichkeiten\\u000a hat ein Hotel,

Diana Payandeh

465

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

SciTech Connect

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

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

2011-05-04

466

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

NASA Astrophysics Data System (ADS)

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

Pepelnjak, Tomaž; Kuzman, Karl; Kokol, Anton

2011-05-01

467

Informatics approach using metabolic reactivity classifiers to link in vitro to in vivo data in application to the ToxCast Phase I dataset  

EPA Science Inventory

Strategic combinations and tiered application of alternative testing methods to replace or minimize the use of animal models is attracting much attention. With the advancement of high throughput screening (HTS) assays and legacy databases providing in vivo testing results, suffic...

468

Georgians Died on Titanic  

Microsoft Academic Search

Hardly anyone remembers the Dona Paz or the Wilhelm Gustloff, but almost everyone knows about the Titanic. However, few know that four Georgians--three men and a woman--were aboard the doomed Titanic, and that the three men died in the catastrophe. The oldest of the men was a 67-year old philanthropist who many years earlier had lived in Georgia for almost

Wilkes Donald E. Jr

1994-01-01

469

Die Klassifikation der Witterungslagen  

Microsoft Academic Search

Zusammenfassung Für die regionale Klassifikation der Witterungslagen in Gebieten von der Grösse des Alpenraumes wird ein Klassifikationsschema vorgeschlagen, welches auf der Grundlage der im Buch vonFlohn: «Witterung und Klima in Mitteleuropa» veröffentlichten Klassifikation vonLauscher aufgebaut ist. DasLauscher'sche Schema wird von 5 auf 6 Klassen und von 17 auf 33 Typen erweitert wodurch es allgemein für beliebige Gebiete verwendbar wird und

Max Schüepp

1959-01-01

470

What Happens When Someone Dies?  

MedlinePLUS

... call 911. But if a person is dying at home and does not want CPR, calling 911 is ... Health Care Decisions ) if the person is dying at home. Publication Date: September 2012 Page Last Updated: June ...

471

Adherence of investment to Au–Pd–Ag alloy using a vacuum–argon pressure casting machine  

Microsoft Academic Search

Objective. The removal of adhered investment material from marginal metal surfaces represents a possible risk of poor marginal adaptation.The aim of this work was to evaluate the effects of argon on investment adherence to the casting surface and on the alloy surface microstructure.Methods. A die of stainless steel was used. 10 wax copings were cast by vacuum–argon pressure, while 10

Tonino Traini; Giovanna Murmura; Nicola Di Lullo; Sergio Caputi

2003-01-01

472

DieHard: probabilistic memory safety for unsafe languages  

Microsoft Academic Search

Applications written in unsafe languages like C and C++ are vul- nerable to memory errors such as buffer overflows, dangling point- ers, and reads of uninitialized data. Such errors can lead to pro- gram crashes, security vulnerabilities, and unpredictable behavior. We present DieHard, a runtime system that tolerates these errors while probabilistically maintaining soundness. DieHard uses ran- domization and replication

Emery D. Berger; Benjamin G. Zorn

2006-01-01

473

Instant Casting Movie Theater: The Future Cast System  

NASA Astrophysics Data System (ADS)

We have developed a visual entertainment system called “Future Cast” which enables anyone to easily participate in a pre-recorded or pre-created film as an instant CG movie star. This system provides audiences with the amazing opportunity to join the cast of a movie in real-time. The Future Cast System can automatically perform all the processes required to make this possible, from capturing participants' facial characteristics to rendering them into the movie. Our system can also be applied to any movie created using the same production process. We conducted our first experimental trial demonstration of the Future Cast System at the Mitsui-Toshiba pavilion at the 2005 World Exposition in Aichi Japan.

Maejima, Akinobu; Wemler, Shuhei; Machida, Tamotsu; Takebayashi, Masao; Morishima, Shigeo