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1

Vacuum Die Casting of Silicon Sheet for Photovoltaic Applications  

NASA Technical Reports Server (NTRS)

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

1979-01-01

2

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

SciTech Connect

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

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

2003-05-01

3

Optimization of plasma-assisted chemical vapour deposition hard coatings for their application in aluminium die-casting  

Microsoft Academic Search

Within this work, different types of commercial hard coatings produced by plasma-assisted chemical vapour deposition (PACVD) were tested in aluminium die-casting applications: TiN, Ti(C,N), Ti(B,N) and (Ti,Al)(C,N). All coatings tested on die-casting cores showed a significant increase in lifetime. To optimize the coating performance and to understand their different behaviour in die-casting, the soldering tendency was characterized employing an immersion

C. Mitterer; F. Holler; C. Lugmair; R. Nöbauer; R. Kullmer; C. Teichert

2001-01-01

4

Bimetallic dies with direct metal-deposited steel on Moldmax for high-pressure die casting application  

Microsoft Academic Search

In high-pressure die casting, cooling time greatly affects the total cycle time. As thermal conductivity is the main governing\\u000a factor, a higher thermal conductive die material allows faster extraction of heat from the casting, thus resulting in shorter\\u000a cycle time and higher productivity. This paper presents a novel approach to replace a conventional steel die by a bimetallic\\u000a die made

M. Khalid Imran; S. H. Masood; Milan Brandt

2011-01-01

5

Sputtered Protective Coatings for die Casting Dies.  

National Technical Information Service (NTIS)

This investigation determined whether selected ion beam sputtered coatings on H-13 die steel would have the potential of improving the thermal fatigue behavior of the steel used as a die in aluminum die casting. The coatings were selected to test candidat...

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

1981-01-01

6

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

Microsoft Academic Search

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

Yuecel Birol; Feriha Birol

2007-01-01

7

Sputtered protective coatings for die casting dies  

NASA Technical Reports Server (NTRS)

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

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

1981-01-01

8

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

9

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

10

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

Microsoft Academic Search

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

Yücel Birol; Feriha Birol

2008-01-01

11

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

12

Benchmarking aluminium die casting operations  

Microsoft Academic Search

Increasing demand in world automotive markets for aluminium die cast components is creating significant opportunities and challenges for the Australian industry, which is positioning itself as a global player. To meet these challenges, the industry is continuously seeking to improve its overall resource efficiency that can result in the reduction of cost and impact on green house gas (GHG) emissions.

A. Tharumarajah

2008-01-01

13

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

14

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

15

New Lubricant for Pressure Die Casting.  

National Technical Information Service (NTIS)

Three lubricant formulations for the pressure die casting of large and complex castings were developed. The lubricants include mineral oils, synthetic acids, finely dispersed graphite preparations, etc. The new lubricants are not inferior in their propert...

B. P. Khrenov L. A. Tabanov L. Y. Kisilenko V. V. Romanov

1972-01-01

16

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

Microsoft Academic Search

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

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

2005-01-01

17

Numerical simulation of low pressure die casting of magnesium wheel  

Microsoft Academic Search

The application of magnesium in the automotive industry contributes to reduced fuel consumption and CO2 emissions. Nowadays, most magnesium components in automobiles are manufactured by die casting. In this paper, simulation\\u000a of the low pressure die casting process of a magnesium wheel that adopts FDM (finite difference method) is presented. Through\\u000a calculating the temperature and velocity fields during filling and

Ying-chun Wang; Da-yong Li; Ying-hong Peng; Xiao-qin Zeng

2007-01-01

18

Electric Heating for Pressure Die Casting Nozzles.  

National Technical Information Service (NTIS)

The possibility of using electric heating of magnesium pressure die casting nozzles has been investigated. Temperature calculations were carried out which indicated its feasibility. A test rig was built and temperature gradients in a full size nozzle were...

R. Stevens

1977-01-01

19

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

20

Die-casting powdery mold releasing agent  

US Patent & Trademark Office Database

A die-casting powdery mold releasing agent according to this invention is a mold releasing agent comprising a mixture of powdery or granulated mold releasing base material composed of an inorganic compound as used for lubricant in a solid form and an organic compound giving adhesive property to the mold releasing agent, the both having powdery or granulated configurations, or configurations in which the organic compound is covered on the mold releasing base material. The mold releasing agent allows production of castings of high quality, in the die-casting method with good workability and without worsening environmental situations.

1991-08-13

21

Spray-formed tooling for injection molding and die casting applications  

SciTech Connect

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

K. M. McHugh; B. R. Wickham

2000-06-26

22

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

23

Formation of defect bands in high pressure die cast magnesium alloys  

Microsoft Academic Search

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

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

2001-01-01

24

Aluminium–aluminium compound fabrication by high pressure die casting  

Microsoft Academic Search

This study examines the development of aluminium–aluminium compounds during high pressure die casting. An aluminium insert was mounted into a die casting mould and embedded into an aluminium casting alloy. Prior to that, the natural oxide layer of the insert was removed and replaced by zinc coatings with different thicknesses. During the casting process the zinc layer dissolves and a

M. Rübner; M. Günzl; C. Körner; R. F. Singer

2011-01-01

25

Integrated optimization system for high pressure die casting processes  

Microsoft Academic Search

High pressure die casting (HPDC) is a versatile process for producing engineered metal parts by forcing molten metal under high pressure into reusable steel dies. However there are a large number of attributes involved which contribute to the complexity of the process. A novel integrated approach is developed to optimize the high pressure die casting processes. The die temperature profiles

L. X. Kong; F. H. She; W. M. Gao; S. Nahavandi; P. D. Hodgson

2008-01-01

26

Friction Stir Welding of Magnesium Die Castings  

Microsoft Academic Search

Friction stir welding (FSW), being a solid-state process, is an attractive method for joining magnesium die castings. In this study, FSW of AZ91D and AM50A plates was performed both on the individual alloys and to join them together. The welds were sound and free from defects, except for small surface cracks in AM50A; a fine microstructure characterized the weld zones.

Jan Ivar Skar; Haavard Gjestland; Ljiljana Djapic Oosterkamp; Darryl L. Albright

27

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

Microsoft Academic Search

The present article deals with the application of a new measurement method to determine the heat-transfer coefficient (HTC)\\u000a and the heat flux density at the casting-die interface during high-pressure die casting (HPDC) and solidification of the magnesium\\u000a AZ91D alloy. The main measurements during the trial included velocity and the position of the piston that delivers the metal\\u000a into the die,

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

2008-01-01

28

Vacuum assisted high pressure die casting of aluminium alloys  

Microsoft Academic Search

High pressure die castings usually contain gas porosity due mainly to the entrapment of air or gas in the melt during the very high speed injection of the molten metal into the cavity. In this paper, the advantages of using an evacuated die cavity during mould filling were evaluated. ASTM standard die casting tensile specimens of three Al alloys, Al–5%Si,

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

2000-01-01

29

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

30

Deburring die-castings by wet vibratory plant  

NASA Technical Reports Server (NTRS)

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

Loeschbart, H. M.

1980-01-01

31

High-pressure die casting: effect of fluid flow on the microstructure of LM24 die-casting alloy  

Microsoft Academic Search

The effect of fluid flow rate on the microstructure of LM24 high pressure die-casting alloy was studied using a fully controlled cold chamber high-pressure die-casting machine and casting a series of rectangular coupons of 65 × 130 × 4 mm. All castings showed a bimodal distribution of dendrites in which the morphology of dendrites was completely different to the classic

M. R. Ghomashchi

1995-01-01

32

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

33

Performance evaluation of PVD coatings for high pressure die casting  

Microsoft Academic Search

During high-pressure die-casting (HPDC) of aluminium alloys, there is a tendency for the molten alloy to react with the tool steel die, core pins and inserts. This occurrence within the high pressure die casting (HPDC) industry is referred to as ‘soldering’. It is of concern to high-pressure die casters because of down-time due to the regular removal of the soldered

S. Gulizia; M. Z. Jahedi; E. D. Doyle

2001-01-01

34

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

35

Marketing and Technology Enhancement Project for the Domestic Die Casting Industry.  

National Technical Information Service (NTIS)

The domestic die casting industry was experiencing strong competition from overseas suppliers due to increasing imports of end-use products (which incorporated die cast components produced offshore) and purchases of offshore produced die castings by U.S. ...

1989-01-01

36

MIG and laser welding of aluminium alloy pressure die cast parts with wrought profiles  

Microsoft Academic Search

Using pressure die cast parts offers new possibilities for producing lightweight complex structures. A typical example is represented by the combination of different aluminium alloy extruded profiles joined by means of cast joints acting as connecting parts. A well-known application of this technique is the manufacture of the AUDI A8 (Fig. 1) as well as the second generation AUDI A2

S. Wiesner; M. Rethmeier; H. Wohlfart

2005-01-01

37

Microstructures and properties of aluminum die casting alloys  

SciTech Connect

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

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

1998-10-01

38

Creep studies of AZ91D pressure die casting  

Microsoft Academic Search

Creep properties of pressure die cast AZ91D magnesium alloy (9% Al-1% Zn) were investigated in the temperature range of 150–180 °C and load range of 30–100 MPa. The pressure die cast material is characterized by a small grain size of about 10 ?m. Creep tests were performed under constant load and under varying load. Creep rates were found to be

M. Regev; E. Aghion; A. Rosen

1997-01-01

39

A reclassification of the die-filling stages in pressure die-casting processes  

Microsoft Academic Search

Traditionally, the die-filling process in pressure die-casting is divided into three stages. This paper initiates the concept of a ‘five-stage’ process for one-shot pressure die-casting processes. The concept of a ‘five-stage’ process retains the familiar first and second stages, breaks down the third stage into two and adds a fifth ‘residual stage’. It is shown that the maximum metal pressure

Y. B. Lui; W. B. Lee; B. Ralph

1996-01-01

40

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

National Technical Information Service (NTIS)

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 c...

C. E. Mobley J. Brevick

1997-01-01

41

INVESTIGATION OF THE SOLDERING REACTION IN MAGNESIUM HIGH PRESSURE DIE CASTING DIES  

Microsoft Academic Search

Soldering in high pressure die casting (HPDC) of magnesium alloys is be- lieved not to occur because of the poor affinity between magne sium and iron. However, information from industry showed that a soldered layer is formed

C. Tang; M. Z. Jahedi

42

Formation and progression of die soldering during high pressure die casting  

Microsoft Academic Search

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

Z. W. Chen

2005-01-01

43

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

NASA Technical Reports Server (NTRS)

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

1982-01-01

44

Energy and Technology Assessment of Zinc and Magnesium Die Casting Plants. Technical Report Close-Out.  

National Technical Information Service (NTIS)

Twin City Die Castings Company of Minneapolis, Minnesota, Twin City Die Castings Company was awarded project No. DE-FG36-05GO15097 to perform plant wide assessments of ten (10) die casting facilities that produce zinc and magnesium alloy castings in order...

T. Heider

2006-01-01

45

Low-pressure die casting of magnesium alloy AM50: Response to process parameters  

Microsoft Academic Search

Low-pressure die casting (LPDC) process has been successfully used to produce sound magnesium alloy AM50 castings. The influence of process parameters: filling time, pressure holding time, die temperature, holding pressure and casting temperature, on the mechanical properties, microstructure and density of LPDC castings were studied. The optimal process parameters for LPDC casting have been experimentally determined as follows: filling time

Penghuai Fu; Alan A. Luo; Haiyan Jiang; Liming Peng; Yandong Yu; Chunquan Zhai; Anil K. Sachdev

2008-01-01

46

Hard coatings to prevent the washout phenomena in high pressure die casting tools  

Microsoft Academic Search

Hard thin coatings were deposited on a hot working tool steel to enhance its resistance to washout in high pressure die casting\\u000a application. The washout is a complex phenomenon of degradation where erosion, soldering, corrosion usually occur jointly.\\u000a All of these phenomena are major sources of limitation to the die service life. The application of hard PVD coatings may result

D. Ugues; E. Torres; M. Perucca; M. Albertinazzi; M. Rosso

2006-01-01

47

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

48

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

49

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

Microsoft Academic Search

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

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

1999-01-01

50

The Simulation of Magnesium Wheel Low Pressure Die Casting Based on PAM-CAST™  

NASA Astrophysics Data System (ADS)

Magnesium is the lightest metal commonly used in engineering, with various excellent characteristics such as high strength and electromagnetic interference shielding capability. Particularly, the usage of magnesium in automotive industry can meet better the need to reduce fuel consumption and CO2 emissions. Nowadays, most current magnesium components in automobiles are made by die casting. In this paper, commercial software for die casting, PAM-CAST™, was utilized to simulate the low pressure die casting process of magnesium wheel. Through calculating temperature field and velocity field during filling and solidification stages, the evolution of temperature distribution and liquid fraction was analyzed. Then, the potential defects including the gas entrapments in the middle of the spokes, shrinkages between the rim and the spokes were forecasted. The analytical results revealed that the mold geometry and die casting parameters should be improved in order to get the sound magnesium wheel. The reasons leading to these defects were also analyzed and the solutions to eliminate them were put forward. Furthermore, through reducing the pouring velocity, the air gas entrapments and partial shrinkages were eliminated effectively.

Peng, Yinghong; Wang, Yingchun; Li, Dayong; Zeng, Xiaoqin

2004-06-01

51

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

52

Laser surface hardening of ductile cast iron for vehicle die  

NASA Astrophysics Data System (ADS)

Experiments of laser transformation hardening were performed with various process parameters on the surface of ductile cast iron block, which is often used for vehicle body. The distribution of microhardness along the case depth direction and the variation of microstructure of hardened track were investigated. Wear test was carried out using a ball-on-flat-type wear-test machine. The results indicate that the hardened layers after the laser surface hardening treatment have excellence wear resistance. It is seen that the surface hardness of ductile cast iron blocks increases greatly at suitable values of process parameters in laser transformation hardening, which satisfies the vehicle dies.

Xu, Yanghui; Liu, Jichang

2010-11-01

53

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

Microsoft Academic Search

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

S Mathieu; C Rapin; J Hazan; P Steinmetz

2002-01-01

54

Rule-based quotation costing of pressure die casting moulds  

Microsoft Academic Search

An actual analysis in the tool and mould making sector showed that methods and programs insufficiently support the manufacturers\\u000a of pressure die casting moulds in the quotation costing process. The primary aim of quotation costing is to generate many\\u000a first-class bids in order to gain a high quantity of profitable orders. For this purpose companies have to achieve a high

B. Denkena; L.-E. Lorenzen; J. Schürmeyer

2009-01-01

55

Onset of fracture in high pressure die casting aluminum alloys  

Microsoft Academic Search

This paper deals with the development of a phenomenological criterion for the prediction of crack initiation in engineering structures made of the pressure die casting alloy Al–10Si–Mg–Mn. A custom-made biaxial testing device is employed to load a newly-designed flat specimen under various combinations of shear and normal loading. In a hybrid experimental–numerical approach, the crack initiation could be studied for

Dirk Mohr; Roland Treitler

2008-01-01

56

WARM WATER SCALE MODEL EXPERIMENTS FOR MAGNESIUM DIE CASTING  

Microsoft Academic Search

High-pressure die casting (HPDC) involves the filling of a cavity with the molten metal through a thin gate. High gate velocities yield jet break-up and atomization phenomena. In order to improve the quality of magnesium parts, the mold filling pattern, including atomization phenomena, needs to be understood. The goal of this study was to obtain experimental data on jet break-up

Sabau; Adrian S

2006-01-01

57

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

58

Final Report on the Effects of Externally Solidified Product on Wave Celerity and Quality of Die Cast Products.  

National Technical Information Service (NTIS)

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 ch...

2003-01-01

59

Potential of die casting for the production of near net shape uranium parts.  

National Technical Information Service (NTIS)

This report provides a detailed summary of a literature survey on the near net shape die casting process. Die casting is one of the near net shape casting technologies which could potentially satisfy the requirements of the LANL program titled Near Net Sh...

E. Robertson

1993-01-01

60

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

61

Heat Treatment of High-Pressure Die Castings  

Microsoft Academic Search

High-pressure die-cast Al alloys cannot normally be heated at high temperatures due to the presence of pores containing entrapped\\u000a gases, which lead to the formation of surface blisters. It has been found that blistering can be avoided by using considerably\\u000a shorter solution-treatment times and lower temperatures. Experiments with alloys 360 (Al-9.5Si-0.5Mg) and 380 (Al-8.5Si-3.5Cu)\\u000a have shown that strong responses to

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

2007-01-01

62

Ultrasonic monitoring of injection molding and die casting  

NASA Astrophysics Data System (ADS)

On-line ultrasonic monitoring of polymer injection molding and aluminum die casting are presented. The flow front of molten polymer and aluminum inside the mold has been proved by a multiple-channel acquisition system with a time resolution up to 1 ms. This information may be used to control the plunger movement. The gap development, due to the shrinkage of the part in the mold, and the part solidification are also monitored for the understanding of the cooling process. As expected, it is observed that thicker sections take longer times to solidify. For injection molding, the relation between the gap formation time and packing pressure has been investigated. Since the temperature of molten aluminum is around 700 degrees C, ultrasonic waveguides are inserted into the die for the monitoring.

Cao, Bin; Wang, H.; Jen, Cheng-Kuei; Nguyen, N. T.; Legoux, J.; Loong, Chee A.; Viens, Martin

1996-11-01

63

Machining studies of die cast aluminum alloy-silicon carbide composites  

Microsoft Academic Search

Metal matrix composites (MMCs) with high specific stiffness, high strength, improved wear resistance, and thermal properties\\u000a are being increasingly used in advanced structural, aerospace, automotive, electronics, and wear applications. Aluminum alloy-silicon\\u000a carbide composites were developed using a new combination of the vortex method and the pressure die-casting technique in the\\u000a present work. Machining studies were conducted on the aluminum alloy-silicon

Thambu Sornakumar; Marimuthu Kathiresan

2010-01-01

64

A method for surface quality assessment of die-castings based on laser triangulation  

Microsoft Academic Search

This paper presents a new method for the surface quality assessment of safety-critical die-castings. We have developed a measurement system that measures the surface of a die-casting and provides quantitative surface quality assessment within a die-casting cycle of 70 s. The measurement system, based on the laser triangulation principle, has an asymmetrical measuring range and is capable of high-resolution measurements

Drago Bracun; Valter Gruden; Janez Mozina

2008-01-01

65

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

66

WARM WATER SCALE MODEL EXPERIMENTS FOR MAGNESIUM DIE CASTING  

SciTech Connect

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

Sabau, Adrian S [ORNL

2006-01-01

67

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

Microsoft Academic Search

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

K. Davey; S. Bounds

1997-01-01

68

Inventory of pollution reduction options for an aluminium pressure die casting plant  

Microsoft Academic Search

This study presents an overview of options aiming to reduce emissions to air, soil and water from an aluminium die casting plant located in Portugal. We identify eighteen pollution reduction options and then estimate their potential to reduce the pollution, and the costs associated with their implementation to the die casting plant. The different types of options considered include typical

Belmira Neto; Carolien Kroeze; Leen Hordijk; Carlos Costa

2009-01-01

69

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

70

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

71

The effects of die relief agent on the retention of full coverage castings.  

PubMed

The effect of a commercial die relief agent on the retention of castings cemented with a zinc phosphate, a zinc polycarboxylate, or a modified zinc oxide-eugenol cement was studied. Forces required to dislodge unspaced castings from tooth preparations were higher when zinc phosphate cement was the luting medium. Die relief agents resulted in a 32% reduction in the forces required to dislodge castings cemented with zinc phosphate. Data for the other cements did not differ statistically. Shear strength-tensile ratios of the cements indicate that the high shear strength provided by zinc phosphate cement may be negated by the cementation of oversize castings fabricated from relieved dies. PMID:6352908

Vermilyea, S G; Kuffler, M J; Huget, E F

1983-08-01

72

A comparison of the accuracy of two removable die systems with intact working casts.  

PubMed

This study evaluated the reproducibility of die position using two removable die systems and two die stones. Poly(vinyl siloxane) impressions were made of a stainless steel, U-shaped arch with four evenly spaced abutments. Six groups were evaluated: Zeiser system/Fuji Rock; Zeiser system/Die Keen; solid cast/Fuji Rock; solid cast/Die Keen; Fuji Rock/Pindex; and Die Keen/Pindex. An optical comparator was used to measure the height of each abutment, the distance between the anterior abutments, and the distance between the posterior abutments. The Zeiser system with either Fuji Rock or Die Keen yielded the greatest accuracy. Die Keen exhibited more linear expansion than Fuji Rock, and solid casts had less distortion than the Pindex system. PMID:8148023

Aramouni, P; Millstein, P

1993-01-01

73

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

NASA Astrophysics Data System (ADS)

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.; Parappagoudar, M. B.

2010-10-01

74

INCREASING THE LIFETIME OF ALUMINIUM AND MAGNESIUM PRESSURE DIE CASTING MOULDS BY ARC ION PLATING PVD COATINGS  

Microsoft Academic Search

Nowadays PVD coatings are wide-spread and state of the art in the machining industry. Due to their properties, like high hardness, corr osion resistance and high temperature stability, PVD coatings have achieved large industrial applications. In this paper, PVD coatings are used for extending the lifetime of a pressure casting mould. A main factor influencing the lifetime of a die

E. Lugscheider; K. Bobzin; T. Hornig; M. Maes

75

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

Microsoft Academic Search

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

Elena Bassoli; Luca Iuliano; Alessandro Salmi

2010-01-01

76

EDM Studies on Aluminum Alloy-Silicon Carbide Composites Developed by Vortex Technique and Pressure Die Casting  

Microsoft Academic Search

Aluminum based metal matrix composites (MMCs) offer potential for advanced structural applications when high specific strength and modulus, as well as good elevated temperature resistance, are important. In the present work, aluminum alloy-silicon carbide composites were developed using a new combination of vortex method and pressure die casting technique. Electrical Discharge Machining (EDM) studies were conducted on the aluminum alloy-silicon

M. Kathiresan; T. Sornakumar

77

NUMERICAL MODELS AND THEIR VALIDITY IN THE PREDICTION OF HEAT CHECKING IN DIE CASTING TOOLING  

Microsoft Academic Search

Heat checking is a major mode of failure of steel die surfaces in aluminum die casting. This cracking initiates due to the large thermal sh ock experienced by the die surface when it is rapidly quenched by the lubricant spray and propagates due to thermal cycling during production due to thermal cycling. Most of the previous studies have focused on

A. Srivastava; V. Joshi; R. Shivpuri

78

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

79

Investigation of the interface phenomena and its effect on erosion and corrosion in aluminum die casting  

NASA Astrophysics Data System (ADS)

When performing an aluminum die casting operation, hot molten metal is injected into the die cavity. The die locks for part solidification. After the part solidifies, the casting will eject from the die. During this operation, the die surface experiences thermal cycling, high velocity impingement, chemical attack and interface friction. Thermal cycling leads to heat checking wear, high velocity impingement to erosive wear, chemical attack to soldering, and interface friction to the part bending and/or galling during ejection. The die casting process is a very capital intensive operation. All the above problems result in down time of the die casting shop. This down time results in loss of production and ultimately loss of capital. The purpose of this study is to (a) investigate the physical and chemical phenomena active at the die-cast aluminum metal interface, and (b) understand the performance of selected die surface treatments in protecting the interface from aluminum foundry alloy. Four laboratory tests were selected to study the aluminum die casting stages: (a) molten metal injection stage (erosive test), (b) filling and solidification (dissolution and wettability tests), and (c) parts ejection stage (friction test). Both qualitative and quantitative results were generated. This research produced many interesting discussions. In erosive testing, in addition to impingement velocity, the melt superheat and alloy types also found to play an important role in the erosion of the die steel. In the past, die casters believed that the higher molten aluminum temperature would cause higher erosive wear loss. However, this study found lower melt temperatures to result in greater erosive wear. In dissolution testing, the alloy elements were found to play an important role. In the past, die casters thought that Fe (Iron) was the main element which affects the dissolution of the die steel into the molten aluminum. This was found not to be necessary true. The Mn and Si content in the alloy also affects the die steel dissolution to a great extent. In wettability testing, the contact angle of the die steel surface was found to correlate well to the soldering phenomena. The friction coefficients of different surface treatments and cast alloy pairs were measured. There was no significant difference among all the surface coatings or treatments. The results of this investigation help explain the interface mechanisms present during a die casting operation and that effect on the die wear and machine down time related problem. It also provides guidelines for further research in the study and control of these mechanisms.

Chu, Yeou-Li

80

Complete Simulation of High Pressure Die Casting Process  

Microsoft Academic Search

The use of simulation programs saves time and reduces the costs of the casting system design. At the same time it is possible to meet stringent product quality. Simulation can make a casting system optimal: it enables the producing of sound, high-quality castings with fewer experiments. Furthermore environmental savings and economical use of materials can be achieved when the number

Matti Sirviö; Sami Vapalahti; Jukka Väinölä

81

Effect of die geometry on the microstructure of indirect squeeze cast and gravity die cast 5083 wrought Al alloy and numerical analysis of the cooling behavior  

Microsoft Academic Search

The indirect squeeze-casting of wrought Al–4.7Mg–0.7Mn (5083) Al alloy has been investigated as functions of die geometry and applied pressure. The two-dimensional implicit finite element computer code for heat-transfer analysis, TOPAZ2D, was used to simulate the cooling curves obtained from the indirect squeeze-casting process. In order to account for latent heat release and the boundary conditions, the equivalent heat capacity

J. H. Lee; H. S. Kim; S. I. Hong; C. W. Won; S. S. Cho; B. S. Chun

1999-01-01

82

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

83

Hot compression behavior of the AZ91 magnesium alloy produced by high pressure die casting  

Microsoft Academic Search

The hot deformation behavior of a Mg–9Al–1Zn alloy produced by high pressure die casting has been investigated by means of compression tests in the temperature and strain rate ranges of 125–300°C and 1.6×10?5 to 10?1s?1, respectively. The samples were deformed in the high pressure die casting state or after an exposure at 415°C for 2h to evaluate any different response

E. Cerri; P. Leo; P. P. De Marco

2007-01-01

84

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

Microsoft Academic Search

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

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

2006-01-01

85

The effect of increased pressure on interfacial heat transfer in the aluminium gravity die casting process  

Microsoft Academic Search

Contraction and distortion of a casting during cooling within a mould can force their respective surfaces together, with the\\u000a associated increased interfacial pressure resulting in increased interfacial heat transfer. This problem has been examined\\u000a for the case of gravity and low pressure die casting of an Al alloy, where an insulating coating is applied to the die cavity\\u000a to assist

W. D. Griffiths; K. Kawai

2010-01-01

86

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

Microsoft Academic Search

The AE44 (Mg–4Al–4RE) alloy was prepared by a hot-chamber die casting method. The microstructure, microstructural stability and creep properties at 175 °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 ?-Mg, Al11RE3, Al2RE and Al2.12RE0.88 phases.

Tomasz Rzycho?; Andrzej Kie?bus; Jan Cwajna; Jaros?aw Mizera

2009-01-01

87

Calculated phase diagrams and the corrosion of die-cast Mg–Al alloys  

Microsoft Academic Search

The corrosion of commercial die-cast Mg–Al alloys was elucidated by a study, of the corrosion in 3% NaCl, of (i) high-pressure die-cast (HPDC) model Mg–Al alloys, (ii) low-purity Mg, (iii) high-purity (HP) Mg and (iv) HP Mg heat treated at 550°C. HPDC is the most important route for the production of Mg components. The corrosion of the model alloys was

Ming Liu; Peter J. Uggowitzer; A. V. Nagasekhar; Patrik Schmutz; Mark Easton; Guang-Ling Song; Andrej Atrens

2009-01-01

88

Casting dimensional control and fatigue life prediction for permanent mold casting dies. Technical report, September 29, 1993--May 31, 1997  

SciTech Connect

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 casting. The influence of process variation and casting geometry variables on dimensional tolerances have been investigated. Also efforts leading to the developments 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. Validation trials using a permanent mold casting machine have indicated the success of the temperature distribution model developed. A combination of experimental and modeling techniques have been employed to extend their knowledge of permanent mold casting. The influence of coatings on casting solidification and mold temperatures has been determined. The computer model has been extended to predict thermally induced stresses and strains in the mold and to predict the number of cycles required to crack the mold. Experimental results have been used to validate the extended model.

NONE

1997-06-01

89

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

90

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

Microsoft Academic Search

The heat transfer at the metal-die interface is believed to have great influence on the solidification process and cast structure\\u000a of the high-pressure die-casting (HPDC) process. The present article focused on the effects of process parameters, casting\\u000a thickness, and alloys on the metal-die interfacial heat-transfer coefficient (IHTC) in the HPDC process. Experiment was carried\\u000a out on a cold-chamber die-casting machine

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

2008-01-01

91

Steady state thermal model for the hot chamber injection system in the pressure die casting process  

Microsoft Academic Search

This paper describes a three-dimensional numerical model that is used to predict the steady state thermal behaviour of the metal injection system of a hot chamber pressure die casting machine. The behaviour of the injection system is considered in conjunction with that of the die. The boundary element method (BEM) is employed, as surface temperatures are of primary importance. The

I. Rosindale; K. Davey

1998-01-01

92

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

Microsoft Academic Search

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

Wenping Jiang; Pal Molian

2001-01-01

93

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

94

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

SciTech Connect

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

Madhav Rao Gonvindaraju

1999-10-18

95

Skin solidification during high pressure die casting of Al–11Si–2Cu–1Fe alloy  

Microsoft Academic Search

Surface regions of Al–11Si–2Cu–1Fe alloy castings produced by high pressure die casting (HPDC) were examined and three microstructural features were observed. In locations of direct melt impingement, there was not an ?-Al rich layer. In most surface locations, a porosity-free ?-Al rich layer was observed. However, in surface locations of low impact of melt, a porosity-free layer being a mixture

Z. W. Chen

2003-01-01

96

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

Microsoft Academic Search

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

P.. Cavaliere; P. P. De Marco

2007-01-01

97

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

98

Through-process numerical simulations of the structural behaviour of Al–Si die-castings  

Microsoft Academic Search

A through-process methodology for numerical predictions of the structural performance of thin-walled aluminium castings is presented. The methodology has been validated against experimental investigations of generic AlSi9MgMn components produced by high-pressure die-casting (HPDC). An experimental database consisting of both material tests and component tests has been established in a previous work [C. Dørum, H.I. Laukli, O.S. Hopperstad, M. Langseth, European

Cato Dørum; Hans I. Laukli; Odd Sture Hopperstad

2009-01-01

99

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

Microsoft Academic Search

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

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

2009-01-01

100

Structural behaviour of Al–Si die-castings: Experiments and numerical simulations  

Microsoft Academic Search

Axial crushing and three-point bending tests have been performed in order to establish an experimental database of the behaviour of generic high-pressure die-cast (HPDC) Al–Si alloys. The experimental data are used to obtain a validated methodology for finite element modelling of thin-walled cast components subjected to quasi-static loading. The HPDC structural components are modelled in the non-linear explicit FE-code LS-DYNA

C. Dorum; H. I. Laukli; O. S. Hopperstad; M. Langseth

2009-01-01

101

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

Microsoft Academic Search

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, beta-phase particles, Mn-rich inclusions, rare earth-rich intermetallics, dendrite cell size, and surface segregation phenomena.

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

2008-01-01

102

Laser surface hardening of ductile cast iron for vehicle die  

Microsoft Academic Search

Experiments of laser transformation hardening were performed with various process parameters on the surface of ductile cast iron block, which is often used for vehicle body. The distribution of microhardness along the case depth direction and the variation of microstructure of hardened track were investigated. Wear test was carried out using a ball-on-flat-type wear-test machine. The results indicate that the

Yanghui Xu; Jichang Liu

2010-01-01

103

Studies on Flow Characteristics at High-Pressure Die-Casting  

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

104

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

105

Effect of melt cleanliness on the formation of porosity defects in automotive aluminium high pressure die castings  

Microsoft Academic Search

The effect of melt cleanliness on the formation of porosity defects in automotive aluminium high pressure die castings (TA Transmission Case) was investigated experimentally. The experiments were conducted under actual industrial production conditions at Nissan Casting Australia Pty Ltd. (NCAP). It was found that the probability of rejection due to excessive porosity present at critical locations in the castings (determined

C Tian; J Law; J van der Touw; M Murray; J.-Y Yao; D Graham; D St. John

2002-01-01

106

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

Microsoft Academic Search

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

F Faura; J López; J Hernández

2001-01-01

107

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

Microsoft Academic Search

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

P. Cavaliere; P. P. De Marco

2007-01-01

108

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

109

Short shots and industrial case studies: Understanding fluid flow and solidification in high pressure die casting  

Microsoft Academic Search

The geometric complexity and high fluid speeds involved in high pressure die casting (HPDC) combine to give strongly three dimensional fluid flow with significant free surface fragmentation and splashing. A simulation method that has proved particularly suited to modelling HPDC is Smoothed Particle Hydrodynamics (SPH). Materials are approximated by particles that are free to move around rather than by fixed

Paul W. Cleary; Joseph Ha; Mahesh Prakash; Thang Nguyen

2010-01-01

110

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

Microsoft Academic Search

This study explores a model (MIKADO) to analyse scenarios for the reduction of the environmental impact of an aluminium die casting plant. Our model calculates the potential to reduce emissions, and the costs associated with implementation of reduction options. In an earlier paper [Neto, B., Kroeze, C., Hordijk, L., Costa, C., 2008. Modelling the environmental impact of an aluminium pressure

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

2009-01-01

111

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

112

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

113

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

114

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

Microsoft Academic Search

This paper gives a brief overview of HSC technology and presents current progress in high performance machining of cast iron and alloy steels used in die and mold manufacturing. This work covers: (a) theoretical and experimental studies of tool failure and tool life in high-speed milling of hard materials, (b) optimization of CNC programs by adjusting spindle RPM and feed

P. Fallböhmer; C. A. Rodr??guez; T. Özel; T. Altan

2000-01-01

115

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

116

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

Microsoft Academic Search

Microstructure-affected micromechanisms of fatigue crack growth operating near the limit plasticity regime were experimentally\\u000a identified for the four main commercial high-pressure die-cast (HPDC) magnesium alloys: AM50, AM60, AZ91, and AE44. These\\u000a fatigue micromechanisms manifested by the concomitant effects of casting pores, interdendritic Al-rich solid solution layer,\\u000a ?-phase particles, Mn-rich inclusions, rare earth-rich intermetallics, dendrite cell size, and surface segregation phenomena.

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

2008-01-01

117

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

118

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

119

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

SciTech Connect

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

Sabau, Adrian S [ORNL

2006-01-01

120

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

121

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

Microsoft Academic Search

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

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

2001-01-01

122

Properties of alumina particulate reinforced aluminum alloy produced by pressure die casting  

Microsoft Academic Search

In this study, metal–matrix composites of an aluminum–silicon based alloy (LM6) and Al2O3 particles with volume fractions of 0.05, 0.10 and 0.15 and in size of 44, 85 and 125?m were produced using pressure die-casting technique. Density, hardness, tensile strength and wear properties were examined. The density values of the composites increased by adding Al2O3 particle. The hardness of the

Hüseyin Sevik; S. Can Kurnaz

2006-01-01

123

Endurance limit and threshold stress intensity of die cast magnesium and aluminium alloys at elevated temperatures  

Microsoft Academic Search

High cycle fatigue properties of the high-pressure die-cast magnesium alloys AZ91 hp, AS21 hp and AE42 hp and of the aluminium alloy AlSi9Cu3 are investigated at elevated temperatures. Fatigue tests are performed at ultrasonic cyclic frequency and load ratio R=?1. Compared with ambient air environment, the S–N curves determined in warm air of 125°C (magnesium alloys) and 150°C (aluminium alloy)

H. Mayer; M. Papakyriacou; B. Zettl; S. Vacic

2005-01-01

124

Fracture behaviour of pressure die-cast aluminium-graphite composites  

Microsoft Academic Search

Fracture toughness values of pressure die-cast Al-7Si-3 Mg-5 graphite composites were measured and found to be in the range 8–10 MPa m1\\/2. Detailed microstructure of the composite and the fractured surfaces were examined. Defects such as clusters, agglomerations and segregation of graphite particles, play a dominant role in accelerating the fracture process. In addition, the acicular silicon phase present in

U. T. S. Pillai; B. C. Pai; K. G. Satyanarayana; A. D. Damodaran

1995-01-01

125

Electroless nickel-plating on die cast magnesium alloy AZ91D  

Microsoft Academic Search

Electroless nickel-plating on die cast magnesium alloy AZ91D was investigated. Growth of the electroless nickel-plating coating was characterized using scanning electron microscopy. Corrosion resistance of the coating was evaluated by open circuit potential and potentiodynamic polarization curves in 3.5% (mass fraction) NaCl solution. The results show that plating deposition is initiated on the crevices and then spread onto primary ?

JIA Su-qiu; JIA Shu-sheng; YAO Jun

126

Effects of Si content on defect band formation in hypoeutectic Al–Si die castings  

Microsoft Academic Search

Al–3–11% Si alloys have been high-pressure die-cast and characterized microstructurally. Alstruc was used to calculate the solidification characteristics and fraction of eutectic. Defect bands were observed at all Si contents, although their constitution, position and distinctiveness were a function of Si content. The defect bands contain a higher fraction Al–Si eutectic than the surroundings in all alloys, and porosity was

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

2005-01-01

127

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

128

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

NASA Astrophysics Data System (ADS)

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

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

2006-06-01

129

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

130

Machining studies of die cast aluminum alloy-silicon carbide composites  

NASA Astrophysics Data System (ADS)

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

Sornakumar, Thambu; Kathiresan, Marimuthu

2010-10-01

131

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

SciTech Connect

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

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

2012-09-30

132

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

133

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

134

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

Microsoft Academic Search

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

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

1998-01-01

135

Microstructure Formation in AlSi4MgMn and AlMg5Si2Mn High-Pressure Die Castings  

NASA Astrophysics Data System (ADS)

Understanding microstructure formation during high-pressure die casting (HPDC) is important for the effective quality control of high-pressure diecast aluminum-alloy components for high-integrity applications. In this study, two HPDC-specific aluminum alloys, AlSi4MgMn and AlMg5Si2Mn, were cast into tensile test bars by cold-chamber (CC) HPDC. The microstructures of the tensile bar specimens were characterized at different length scales, from the scale of the casting to the scale of the eutectic interlamellar spacing. The results show that the salient as-cast microstructural features, e.g., externally solidified crystals (ESCs), defect bands, the surface layer, grain size distribution, porosity, and hot tears were similar for both alloys. The formation of these features can be understood by considering the influence of flow and solidification during each stage of the HPDC process.

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

2009-07-01

136

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

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

137

Microstructure Formation in AlSi4MgMn and AlMg5Si2Mn High-Pressure Die Castings  

Microsoft Academic Search

Understanding microstructure formation during high-pressure die casting (HPDC) is important for the effective quality control\\u000a of high-pressure diecast aluminum-alloy components for high-integrity applications. In this study, two HPDC-specific aluminum\\u000a alloys, AlSi4MgMn and AlMg5Si2Mn, were cast into tensile test bars by cold-chamber (CC) HPDC. The microstructures of the tensile\\u000a bar specimens were characterized at different length scales, from the scale of

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

2009-01-01

138

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

Microsoft Academic Search

High pressure die cast (HPDC) AZ91D (Mg–8.8wt%Al–0.74wt%Zn–0.29wt%Mn) modified with Ca and Ce was investigated. Thermodynamic calculations of liquid\\/solid equilibrium were confirmed by DTA measurements and solid\\/liquid equilibrium at various temperatures between the liquidus and solidus temperatures.The solidification path of HPDC AZ91 and AZ91 modified with Ca and Ce was calculated using the Termo-Calc program. The microstructure was investigated utilizing optical

L. Shepeleva; M. Bamberger

2006-01-01

139

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

140

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

NASA Astrophysics Data System (ADS)

Creep of die-cast Mg alloys is described as an integral part of their plastic deformation behavior in terms of stress-strain-rate-strain relations. Creep tests yield information on yield stress, work hardening, maximum deformation resistance (minimum creep rate), and work softening. Testing in compression avoids influences by fracture. Data on the alloy AJ52 (5Al, 2Sr) in the temperature range between 135 °C and 190 °C are presented and compared to those for AZ91 and AS21. Die-cast Mg-Al alloys consist of fine grains with a grain boundary region containing intermetallic precipitates. Transmission electron microscopic observations indicate that basal glide is the dominant mechanism of deformation being supplemented by nonbasal glide and twinning to maintain compatiblity between the grains. The deformation resistance can be modeled with a composite approach assuming that the grain boundary region is relatively hard due to precipitation of intermetallic phases. The differences in long-term creep resistance at low stress are explained in terms of different strength and stability of precipitates in the different alloys.

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

2005-07-01

141

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

Microsoft Academic Search

Computer software for the numerical simulation of solidification and mold filling is an effective design tool for cast structural automotive magnesium components. A review of commercial software capabilities and their validation procedures was conducted. Aside form the software assessment, the program addressed five main areas: lubricant degradation, lubricant application, gate atomization, and heat transfer at metal mold interfaces. A test

Adrian S Sabau; Edward C Hatfield; Ralph Barton Dinwiddie; Kazunori Kuwana; Valerio Viti; Mohamed I Hassan; Kozo Saito

2007-01-01

142

An evaluation of fiberglass cast application techniques.  

PubMed

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

Wilson, D G; Vanderby, R

1995-01-01

143

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

144

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

145

Die Usability von Rich Internet Applications  

NASA Astrophysics Data System (ADS)

Interaktiven Services, die dem Themenkreis Web 2.0 zugeordnet werden, haftet unter anderem das Attribut an, besonders leicht bedienbar zu sein. Flickr, Youtube und Wikipedia gelten als Erfolgsprojekte dieser neuen Art von interaktiven Websites. Wodurch zeichnet sich nun eine Usability 2.0 (so es sie überhaupt geben sollte) aus? Was ist zu beachten, wenn so genannte Rich Internet Applications gestaltet werden?

Linder, Jörg

146

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

147

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

148

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

149

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

150

Reconstruction and visualization of complex 3D pore morphologies in a high-pressure die-cast magnesium alloy  

Microsoft Academic Search

Visualization and representation of three-dimensional (3D) pore morphologies in the high-pressure die-cast Mg alloys are of significant interest for understanding and modeling processing–microstructure–properties relationships. In this contribution, an efficient and unbiased montage serial sectioning technique is applied for reconstruction of large volume (?1.24×109?m3) high-resolution (?1?m) 3D microstructure of a high-pressure die-cast AM50 Mg alloy containing gas (air) and shrinkage pores.

S. G. Lee; A. M. Gokhale; A. Sreeranganathan

2006-01-01

151

Optimization of porosity formation in AlSi 9Cu 3 pressure die castings using genetic algorithm analysis  

Microsoft Academic Search

In this investigation, an effective approach based on multivariable linear regression (MVLR) and genetic algorithm (GA) methods has been developed to determine the optimum conditions leading to minimum porosity in AlSi9Cu3 aluminium alloy die castings. Experiments were conducted by varying holding furnace temperature, die temperature, plunger velocities in the first and second stage, and multiplied pressure in the third stage

V. D. Tsoukalas

2008-01-01

152

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

SciTech Connect

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

Selle, J.E.

1988-09-12

153

Creep properties of a zinc-aluminum die-casting alloy as a function of grain size  

NASA Astrophysics Data System (ADS)

Zinc and its alloys are a large component of the metal die-casting industry. Recent research on zinc alloys have focused on both creep resistant formulations for high temperature applications as well as high fluidity formulations for ultra-thin die-casting technology. The described research describes the creep behavior of an ultra-fine grained Zn-Al die-casting alloy which was optimized for high fluidity. The creep studies were carried out over a range of grain sizes. It was found that the limit of refinement of the grain size during cryogenic ball-milling was the low end of the ultra-fine grained regime. The chosen milling time for use in the research that follows was found to have a volume average grain size of 260nm with a relatively large standard deviation of 85nm. Targeted heat treatments were performed at varying temperature and time. Pre and post-heat treatment microscopic examination revealed a well behaved Hall-Petch relationship within the ultra-fine grained regime. Using this information an additional microstructure of 510 nm volume average grain size was chosen for an additional microstructure of interest for study using the impression creep technique. A highly annealed microstructure was also produced using near melting temperatures and long terms in order to remove most of the grain boundaries from the specimen to show the effect they have on the creep behavior. It was found that for both the as-milled condition and the first annealed condition, having volume average grain sizes of 260 and 510nm respectively, that stress exponents near 1 were seen at low stresses transitioning to values in the range of 4-7 at elevated stresses. A stress exponent of 1 along with activation energy values near that of grain boundary diffusion for both cases suggest Coble creep as a potential creep mechanism for the ultra-fine grained samples. Evidence of a threshold stress was seen in the as-milled condition suggesting an interference mechanism with the grain boundary diffusion process. The possibility of oxide dispersions could explain the threshold stress that provides the high grain growth exponents (relative to a nominally pure material) encountered; however, microscopy of the specimens was inconclusive showing relatively few nanocrystalline dispersions to explain such a result. This suggestion also does not explicitly explain the threshold stress disappearing for the ultra-fine grained annealed microstructure. An additional explanation is that of the ball-milling process leading to non-uniform segregation of Al to the grain boundaries as has been suggested in the literature on other alloys processed by ball milling. If true this process could explain the disappearance of the effect after annealing since it is energetically favorable for Al to form a stable second phase under equilibrium conditions. This precipitation could explain the removal of the non-uniform segregation and subsequent absence of a threshold stress for annealed specimens. Highly annealed ball-milling specimens as well as sand-castings of the alloy of interest were tested for comparison to coarse grained tensile creep results. The data shows stress exponent values very close to those of tensile creep tests on coarse grained sand castings.

Gobien, Jeremy Michael

154

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

155

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

156

Computational microstructure analyzing technique for quantitative characterization of shrinkage and gas pores in pressure die cast AZ91 magnesium alloys  

Microsoft Academic Search

Pressure die cast AZ91 magnesium alloy contains both shrinkage and gas microporosity. Quantification and characterization of shrinkage and gas microporosity is expected to be useful to understand the processing-properties-microstructure correlations. However, conventional image analysis techniques do not permit a separate quantification and characterization of shrinkage and gas microporosity. A computational microstructural (image) analyzing technique has been developed by the use

D. G. Leo Prakash; B. Prasanna; D. Regener

2005-01-01

157

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

Microsoft Academic Search

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

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

2006-01-01

158

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

Microsoft Academic Search

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

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

2005-01-01

159

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

Microsoft Academic Search

Residents adjoining a die?casting plant bad 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).

Kaye H. Kilburn; Raphael H. Warshaw

1993-01-01

160

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

161

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

NASA Technical Reports Server (NTRS)

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

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

1996-01-01

162

Experimental and Numerical Study of Air Entrapment During the Filling of a Mould Cavity in Die Casting  

NASA Astrophysics Data System (ADS)

One of the most important problems encountered in die-casting processes is porosity due to air entrapment in the molten metal during the injection process. The aim of this work is to study experimentally and numerically different air entrapment mechanisms that may take place during the filling of a mould cavity (with rectangular shape) in die-casting processes. The numerical simulation of the flow in the die cavity is carried out using a CFD code (FLOW-3D), which is based on a SIMPLE-like approach to solve the coupling between the momentum and mass conservation equations and a Volume of Fluid (VOF) technique for treating the free surface. Also, filling visualization experiments are carried out on a test bench using water as working fluid in a transparent die model and a high-speed camera. The die model is specifically designed and constructed to allow an easy modification of the geometrical configuration of the gate to the die cavity. The numerical and experimental results obtained for the air-water interface evolution are compared for different inlet velocities of the fluid. The purpose is to identify the mechanisms of air entrapment during die filling.

Hernández-Ortega, Juan J.; Zamora, Rosendo; Palacios, Julián; López, Joaquín; Faura, Félix

2007-04-01

163

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

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

164

21 CFR 888.5980 - Manual cast application and removal instrument.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

165

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

166

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

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

167

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

168

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

169

An electron metallographic study of pressure die-cast commercial zinc–aluminium-based alloy ZA27  

Microsoft Academic Search

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

M. DURMAN; S. MURPHY

1997-01-01

170

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

171

Characterization of the effects of process parameters on macrosegregation in a high-pressure die-cast Magnesium alloy  

Microsoft Academic Search

Normal and inverse solute segregations have been reported to occur in several Al-alloys as well as in some other nonferrous alloys. Nonetheless, these phenomena have not been studied in high-pressure die-cast (HPDC) Mg-alloys. This contribution reports an experimental metallographic evidence of inverse surface macrosegregation in a HPDC AM60 Mg-alloy and the effects of process parameters on the extent of inverse

Soon Gi Lee; G. R. Patel; A. M. Gokhale

2005-01-01

172

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

Microsoft Academic Search

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

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

2008-01-01

173

Advanced Pattern Material for Investment Casting Applications  

SciTech Connect

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

F. Douglas Neece Neil Chaudhry

2006-02-08

174

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

175

Quantitative fractographic analysis of variability in the tensile ductility of high-pressure die-cast AE44 Mg-alloy  

Microsoft Academic Search

Cast magnesium alloys often exhibit large variability in fracture related mechanical properties such as ductility and strength. In this contribution, the variability in the tensile ductility of individually cast tensile test specimens of high-pressure die-cast AE44 Mg-alloy is examined at room temperature and at 394K. Significant specimen-to-specimen variations in the ductility are observed at both temperatures. The variability in the

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

2006-01-01

176

Die-casting end-of-fill and drop forge viscometer flow transients examined with a coupled-motion numerical model  

Microsoft Academic Search

In a typical die-casting operation hydraulic injection pressure is set to give a desired shot profile. In reality, the plunger motion is affected by the buildup of pressure in the metal as it flows into the die. In this paper, the motion of the plunger is examined using a coupled-motion numerical model for the plunger and liquid metal. It is

Amol Palekar; Andrei Starobin; Alexander Reikher

177

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

178

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

179

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

180

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

Microsoft Academic Search

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

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

2008-01-01

181

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

SciTech Connect

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

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

2006-04-15

182

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

National Technical Information Service (NTIS)

Computer software for the numerical simulation of solidification and mold filling is an effective design tool for cast structural automotive magnesium components. A review of commercial software capabilities and their validation procedures was conducted. ...

A. S. Sabau E. C. Hatfield K. Saito M. I. Hassan V. Vili

2007-01-01

183

Evaluation of direct pressure sensors for monitoring the aluminum die casting process.  

National Technical Information Service (NTIS)

This study was conducted as part of the US Department of Energy (DOE) sponsored project Die Cavity Instrumentation. One objective of that project was to evaluate thermal, pressure, and gas flow process monitoring sensors in or near the die cavity as a mea...

X. Zhang

1997-01-01

184

CAST  

NSDL National Science Digital Library

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

2012-02-03

185

CAST  

NSDL National Science Digital Library

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

2012-02-06

186

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

NASA Technical Reports Server (NTRS)

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

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

1981-01-01

187

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

NASA Astrophysics Data System (ADS)

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

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

2004-01-01

188

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

189

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

190

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

191

SiC Die Attach for High-Temperature Applications  

NASA Astrophysics Data System (ADS)

Eutectic solders AuIn19 and AuGe12 and nanosilver paste were investigated for SiC die attach in high-temperature (300°C) applications. The soldering or sintering conditions were optimized through die shear tests performed at room temperature. In particular, application of static pressure (3.5 MPa) during sintering resulted in greatly improved mechanical behavior of the nanosilver-based joint. Microstructural study of the eutectic solders showed formation of Au-rich grains in AuGe die attach and significant diffusion of Au and In through the Ni layer in AuIn19 die attach, which could lead to formation of intermetallic compounds. Die shear tests versus temperature showed that the behaviors of the studied die attaches are different; nevertheless they present suitable shear strengths required for high-temperature applications. The mechanical behavior of joints under various levels of thermal and mechanical stress was also studied. Creep experiments were carried out on the eutectic solders to describe the thermomechanical behavior of the complete module; only one creep mechanism was observed in the working range.

Drevin-Bazin, A.; Lacroix, F.; Barbot, J.-F.

2013-11-01

192

Effect of strontium modification on near-threshold fatigue crack growth in an Al-Si-Cu die cast alloy  

SciTech Connect

The effects of strontium modification on microstructure and fatigue properties in a die cast commercial aluminum-silicon alloy are demonstrated. Strontium additions of 0.010 and 0.018 wt pct drastically change the morphology of the eutectic silicon. The influence of these microstructural changes on fatigue properties is evaluated through fatigue crack growth testing. Examination of the fracture surfaces and the crack path establish distinct fatigue fracture modes for the modified and unmodified eutectic structures. Changes in fracture mode and crack path are correlated to the microstructure changes. A higher energy fracture mode and increased crack path tortuosity explain the observed improvement in fatigue properties for the modified alloys. Strontium modified alloys exhibit a 10 to 20 pct higher fatigue crack growth threshold compared to an unmodified alloy for testing at a load ratio of 0.5. No difference was observed for testing at a load ratio of 0.1.

Schaefer, M.; Fournelle, R.A. [Marquette Univ., Milwaukee, WI (United States). Materials Science Program

1996-05-01

193

Morphological features of interfacial intermetallics and interfacial reaction rate in Al11Si2.5Cu(0.15\\/0.60)Fe cast alloy\\/die steel couples  

Microsoft Academic Search

Soldering reactions are commonly observed during high pressure die casting of aluminium alloys, and involve the formation and growth of interfacial intermetallics between the die and the cast alloy. It is generally believed that close to 1% Fe is necessary in the aluminium alloy to reduce soldering. However, the role of iron in the interfacial reaction has not been studied

G. B. Winkelman; Z. W. Chen; D. H. St John; M. Z. Jahedi

2004-01-01

194

QUANTIFICATION DES DÉFAUTS EN FONDERIE SOUS PRESSION PAR RADIOSCOPIE NUMÉRIQUE ET TOMOGRAPHIE HAUTE RÉSOLUTION HIGH PRESSURE DIE CASTING DEFECT QUANTITATIVE MEASUREMENT BY RADIOSCOPIC AND TOMOGRAPHY ANALYSIS  

Microsoft Academic Search

Quantification of internal defects on aluminium high pressure die castings contributes to a better definition and harmonization of acceptance specifications. The radioscopic image analysis allowed extracting reference images (blowhole or shrinkage type) correlated to porosity levels. High resolution tomography (from 3µm to 20µm voxel) enabled to calculate the volume of internal defects and to determine the distribution of the pores

P. HAIRY; P. BOUVET; Y. GAILLARD; V. BUECHER; F. GRANEREAU

195

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

196

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

197

Light weight design with light metal castings  

Microsoft Academic Search

The article gives a number of examples of light weight design with aluminium and magnesium castings. The high perfection of the high-pressure die casting HPDC technology and new design opportunities for net shape or near net shape components will be presented. New applications of particle reinforced light metals offer additional potential for weight saving and better technical, economical and environmental

D Brungs

1997-01-01

198

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

Microsoft Academic Search

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

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

2009-01-01

199

Experimental verification of numerical predictions for the optimum plunger speed in the slow phase of a high-pressure die casting machine  

Microsoft Academic Search

An experimental study of the optimum maximum plunger speed in the slow phase of a high-pressure die casting machine with horizontal\\u000a cold chamber is presented. A special apparatus that uses a photoelectric sensor to determine the instant at which the working\\u000a fluid reaches the runner was developed and installed in the injection chamber. The measured volumes of air remaining in

Rosendo Zamora; Félix Faura; Joaquín López; Julio Hernández

2007-01-01

200

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

Microsoft Academic Search

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

Choong Do Lee

2006-01-01

201

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

Microsoft Academic Search

The objective of this study relates to the numerical simulation of the free surface during the two-dimensional flow and solidification\\u000a of aluminum in the horizontal cylinder and mold cavity of the high pressure die casting HPDC machine with cold chamber. The\\u000a flow is governed by the Navier–Stokes equations (the mass and the momentum conservations) and solved in the two phase’s

Abdel Illah Nabil Korti; Said Abboudi

202

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

NASA Astrophysics Data System (ADS)

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

Biswas, Somjeet; Sket, Federico; Chiumenti, Michele; Gutiérrez-Urrutia, Iván; Molina-Aldareguía, Jon M.; Pérez-Prado, Maria Teresa

2013-09-01

203

Casting materials and their application in research and teaching.  

PubMed

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

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

2014-04-01

204

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

205

Effect of the gap distance on the cooling behavior and the microstructure of indirect squeeze cast and gravity die cast 5083 wrought Al alloy  

Microsoft Academic Search

An indirect squeeze casting process applied to a wrought 5083 Al alloy (Al–4.7Mg–0.7Mn) was investigated experimentally and numerically. A two-dimensional finite element computer code for fully coupled heat transfer and deformation analysis, abaqus, was used to simulate the cooling curves obtained from the experiments. Thermal contraction of the material during solidification creates an air gap between the mold and the

J. H. Lee; H. S. Kim; C. W. Won; B. Cantor

2002-01-01

206

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

207

[The clinical application of Vitallium 2000 casting removable partial denture].  

PubMed

The casting removable partial denture (RPD) is one of most commonly prosthesis methods in present. Vitallium is one kind of dental alloy with cobalt, chromium and molybdenum etc. It has three ranks respectively: Vitallium, Vitallium 2000 and Vitallium 2000 plus. Although the traditional casting RPD are commonly used, but it has been limited in the physical capabilities of traditional dental alloy. It would not been done to flexible design on denture especially on denture base. The elasticity of casting clasp is not good, the volume is thick. Because of the Vickers hardness and elongation of Vitallium 2000 and Vitallium 2000 plus are better than traditional dental alloys, so the RPD with Vitallium 2000 has good bending control, deformation rebound and fracture resistance. The benefit of Vitallium 2000 or Vitallium 2000 plus is the RPD with splitting can be designed for some free end clinical cases, to solve some clinical problems. PMID:19472868

Sun, Feng

2009-04-01

208

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

209

Microstructure and dislocation analysis after creep deformation of die-cast Mg–Al–Sr (AJ) alloy  

Microsoft Academic Search

The microstructure and creep behavior of Mg\\/Al composite crankcases cast with three alloy formulations of the Mg–Al–Sr alloy AJ62 have been investigated. Overall 12 components were used within this study. Multi-level creep tests were conducted to evaluate the creep properties at stresses up to 90MPa and temperatures up to 473K. Microstructure observations including phase characterization and in-depth dislocation analyses were

Martin Kunst; Andreas Fischersworring-Bunk; Gilles L’Esperance; Philippe Plamondon; Uwe Glatzel

2009-01-01

210

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

211

Optimization and continuous casting: Part II. Application to industrial casters  

NASA Astrophysics Data System (ADS)

The optimization of the operation and design of continuous casters is formulated and solved using a nonlinear programing (NLP) strategy. Using objective and constraint functions that relate to casting performance and steel quality, the optimization is performed using a successive quadratic programming (SQP) algorithm applied to a heat flow model. Theoretical development for this approach was presented in Part I of this study.[2] In this article, we present the results of this approach for 12 casting cases. Here, billet and slab caster models were considered for rate maximization, rate minimization, and maximization of enthalpy at the.cutoff point. Both of these are two-dimensional heat flow models based on industrial continuous casters. The results show that optimization is a viable and effective tool for developing operating strategies for casters. Moreover, many of the optimal solutions are not likely to be discovered through normal operating practice or case study. For example, spray heat-transfer coefficients need not be in decreasing order, and the maximum casting rate may be slightly different from the case for maximum enthalpy in the strand.

Lally, B.; Biegler, L. T.; Henein, H.

1991-10-01

212

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

SciTech Connect

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

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

1996-09-01

213

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

NASA Technical Reports Server (NTRS)

A primary concern in modern fluid dynamics research is the experimental verification of computational aerothermodynamic codes. This research requires high precision and detail in the test model employed. Ceramic materials are used for these models because of their low heat conductivity and their survivability at high temperatures. To fabricate such models, slip casting techniques were developed to provide net-form, precision casting capability for high-purity ceramic materials in aqueous solutions. In previous slip casting techniques, block, or flask molds made of plaster-of-paris were used to draw liquid from the slip material. Upon setting, parts were removed from the flask mold and cured in a kiln at high temperatures. Casting detail was usually limited with this technique -- detailed parts were frequently damaged upon separation from the flask mold, as the molded parts are extremely delicate in the uncured state, and the flask mold is inflexible. Ceramic surfaces were also marred by 'parting lines' caused by mold separation. This adversely affected the aerodynamic surface quality of the model as well. (Parting lines are invariably necessary on or near the leading edges of wings, nosetips, and fins for mold separation. These areas are also critical for flow boundary layer control.) Parting agents used in the casting process also affected surface quality. These agents eventually soaked into the mold, the model, or flaked off when releasing the case model. Different materials were tried, such as oils, paraffin, and even an algae. The algae released best, but some of it remained on the model and imparted an uneven texture and discoloration on the model surface when cured. According to the present invention, a wax pattern for a shell mold is provided, and an aqueous mixture of a calcium sulfate-bonded investment material is applied as a coating to the wax pattern. The coated wax pattern is then dried, followed by curing to vaporize the wax pattern and leave a shell mold of the calcium sulfate-bonded investment material. The shell mold is cooled to room temperature, and a ceramic slip is poured therein. After a ceramic shell of desired thickness has set up in the shell mold, excess ceramic slip is poured out. While still wet, the shell mold is peeled from the ceramic shell to expose any delicate or detailed parts, after which the ceramic shell is cured to provide a complete, detailed, precision ceramic article without parting lines.

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

1993-01-01

214

Hydroforming Simulations and Applications in Product Design, Die Development, and Production Trouble Shooting  

Microsoft Academic Search

Since late 1990s, GM Manufacturing Engineering - Die Center has been developing and implementing tube hydroforming simulation technology to GM hydroforming operations. Through successful development and implementation of hydroforming simulation technology, the efficiency and quality of die engineering, tryout, and production have been dramatically improved. This paper presents the critical issues in hydroforming, and the applications of tube hydroforming simulations

Wei Ji; Weidong Wu; Norman Goan; Chuan-Tao Wang; Mark Cline

2005-01-01

215

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

NASA Technical Reports Server (NTRS)

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

Lee, Jonathan A.

2003-01-01

216

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

217

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

218

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

NASA Astrophysics Data System (ADS)

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

Korti, Abdel Illah Nabil; Abboudi, Said

2011-11-01

219

Hydroforming Simulations and Applications in Product Design, Die Development, and Production Trouble Shooting  

NASA Astrophysics Data System (ADS)

Since late 1990s, GM Manufacturing Engineering - Die Center has been developing and implementing tube hydroforming simulation technology to GM hydroforming operations. Through successful development and implementation of hydroforming simulation technology, the efficiency and quality of die engineering, tryout, and production have been dramatically improved. This paper presents the critical issues in hydroforming, and the applications of tube hydroforming simulations in the areas of product development, die development, springback and compensation and trouble shooting in tube hydrofoming production. Finally, the latest developments in sheet hydroforming and simulation technology will be discussed.

Ji, Wei; Wu, Weidong; Goan, Norman; Wang, Chuan-Tao; Cline, Mark

2005-08-01

220

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

221

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

NASA Technical Reports Server (NTRS)

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

Lee, Jonathan A.

2009-01-01

222

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

Microsoft Academic Search

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

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

2001-01-01

223

Isothermal Flow in an Optical Fiber Coating Applicator and Die System  

NASA Astrophysics Data System (ADS)

The isothermal flow generated by a fast-moving optical fiber in a coating applicator and die was studied numerically. Although it is expected that thermal effects can be important in typical coating processes, the isothermal flow behavior should be thoroughly investigated before including the heat transfer considerations. Thus, isothermal flow is studied in this paper, and key parameters that play a major role in the optical fiber coating process are investigated in detail. The coupled partial differential equations that govern the fluid flow are solved on a transformed nonuniform staggered grid. A finite volume method is employed with a semi implicit method for pressure linked equations (SIMPLE)-based algorithm for the pressure calculations. The fiber speed is varied from 0.1 up to 22 m/s, and various applicator sizes are considered. The diameters at the die entrance and at the die exit are varied separately, since the geometry of the applicator and of the die can play an important role. Both free and solid wall surfaces are taken for the boundary condition at the top surface in the applicator. The shear-free condition can be regarded as direct contact of the coating fluid with the cooling gas at the top surface. Three different viscosities were chosen, based on reference temperatures, taken as the fluid inlet temperature, the fiber inlet temperature, and the average temperature. Relatively low pressure differences, compared to those in the applicator and the die, were found at the dynamic contact point where the fiber first enters the coating applicator. This suggests that air or gases used for cooling the fiber may be able to enter through this location. It was also found that the shear rates in this region are comparatively higher. The temperature-dependent viscosities were found to be of critical importance in the flow. The change in size of the applicator did not significantly affect the mass flow rates at the die exit, whereas the pressure gradients and shear rates near the dynamic contact point were strongly affected. The flow field in the die changed substantially with a change in the exit size. Maximum pressures and shear rates in the die increased drastically when the die exit became smaller. This study also suggests that a more accurate representation of the upper meniscus is needed to simulate flow near the fiber entry into the applicator.

Yoo, Sang-Yeoun; Jaluria, Yogesh

2006-01-01

224

Precipitation casting of polycaprolactone for applications in tissue engineering and drug delivery  

Microsoft Academic Search

Microporous materials have been produced by gradual precipitation from solutions of poly(?-caprolactone) (PCL) in acetone induced by solvent extraction across a semi-permeable PCL membrane which is formed in situ at the polymer solution\\/non-solvent interface. Microparticulates of hydroxyapatite and inulin polysaccharide, respectively, were incorporated in precipitation cast PCL matrices to illustrate potential applications in hard tissue repair and macromolecular drug release.

A. G. A. Coombes; S. C. Rizzi; M. Williamson; J. E. Barralet; S. Downes; W. A. Wallace

2004-01-01

225

Machine Casting of Ferrous Alloys.  

National Technical Information Service (NTIS)

A series of iron, nickel, and cobalt base alloys were permanent mold cast under varying conditions to evaluate techniques for improving the integrity of die casting. By appropriate control of heat flow it is possible to achieve permanent mold casting with...

M. F. X. Gigliotti

1974-01-01

226

InP dies transferred onto silicon substrate for optical interconnects application  

Microsoft Academic Search

We bonded quantum well InP dies on a photonic layer transferred on silicon CMOS processed wafer using direct molecular bonding. This approach is suitable for new applications, viz., photonics on silicon, 3D packaging and integrated sensors. The chips are diced from a bulk substrate and bonded directly onto a silicon substrate without any organic nor metallic adhesive layer. A thin

M. Kostrzewa; L. Di Cioccio; M. Zussy; J. C. Roussin; J. M. Fedeli; N. Kernevez; P. Regreny; Ch. Lagahe-Blanchard; B. Aspar

2006-01-01

227

Techniques and applications for integrating a semiconductor laser on a micromachined die  

Microsoft Academic Search

This paper describes methods for attaching a vertical cavity surface emitting laser (VCSEL) on to a surface micromachined die. Techniques investigated include silver paste, soldering, wire bonding, and gold pads with integrated resistive heaters. Each technique is evaluated based on reliability, positioning tolerances, and secondary effects. Applications include single chip laser beam scanning.

Joseph G. Bouchard; Victor M. Bright; David M. Burns

1998-01-01

228

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

229

Laser cladding in the use effects on nitrided and PVD coated steels used for die-casting using various process parameters and techniques Pojavi pri laserskem navarjanju nitriranih in PVD prevle?enih jekel za orodja za tla?no litje z uporabo razli?nih parametrov in tehnik  

Microsoft Academic Search

Repair welding of die-casting tools is approach to extend life cycle of expensive dies. Issues addressed in this paper are problems emerging from repair welding of surface treated steels e.g. nitriding, oxidizing, hard coating or duplex-treating. Cladding tests were car- ried out on various gas nitrided and oxidized or hard coated chrome martempered steel used for die tools. Observed welding

D. BomBa?; J. tušek

230

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

DOEpatents

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

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

1980-09-24

231

The "flatback" cast.  

PubMed

A properly applied above-elbow cast in a child presents difficulties not seen in adults. Because of the differences in anatomy, physiology, and compliance, children can benefit from modification of the standard above-elbow cast. We report on a method of application of the "flatback" cast to address these concerns. PMID:8421630

Black, G B; Klippenstein, N L

1993-01-01

232

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

NASA Technical Reports Server (NTRS)

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

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

2006-01-01

233

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

Microsoft Academic Search

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

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

2006-01-01

234

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

DOEpatents

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

Harlow, J.L.

1981-09-14

235

The viability and possible applications of high resolution mark replicator casting compound in document examination.  

PubMed

Mark replicator casting compounds are commonly associated with recovering toolmark detail. A series of experiments was designed to identify the possible applications, and assess the overall viability, of using mark replicator compound to record indentations on questioned documents. The trials included testing the effect of Isomark High Resolution Mark Replicator on different paper-based substrate types, and observing in particular, any damage that it may cause. The experiments also tested the effect that the mark replicator has on subsequent fingerprinting techniques. It was found that the mark replicator successfully recorded indentations on paper and card surfaces. In some cases, the mark replicator caused staining on some of the surfaces and had a negative effect on the quality of fingerprints subsequently developed. PMID:14964816

Higgins, K; Walker, J D

2004-01-01

236

Microstructures and Mechanical Properties of As-Cast Mg-Zr-Ca Alloys for Biomedical Applications  

NASA Astrophysics Data System (ADS)

The microstructures and mechanical properties of as-cast Mg-Zr-Ca alloys were investigated in this study for potential use in biomedical applications. The Mg-Zr-Ca alloys were fabricated by commercial pure Mg (99.9 mass%), Ca (99.9 mass%), and master Mg-33mass%Zr alloy. The microstructures of the alloys were examined by X-ray diffraction (XRD) analysis and optical microscopy (OM), and the mechanical properties were determined from tensile tests. The experimental results indicate that an increase of Zr obviously increases the strength of Mg-Zr-Ca alloys with 1 mass% Ca and the formation of Mg2Ca decreases the strength of the alloys. Mg-1Zr-1Ca alloy (mass%) has the highest strength and best ductility among all the studied alloys.

Zhou, Ying-Long; An, Jun; Luo, Dong-Mei; Hu, Wang-Yu; Li, Yuncang; Hodgson, Peter; Wen, Cui'e.

2011-06-01

237

Exploratory study on H13 steel dies.  

National Technical Information Service (NTIS)

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...

A. J. Sunwoo

1994-01-01

238

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

239

A multi-physics model for microwave heating in metal casting applications embedding a mode stirrer  

Microsoft Academic Search

Microwave heating can be employed to improve the metal casting process. However, the usage of microwave ovens for casting imposes some specific problems which do not occur in conventional heating processes. In this paper, an approach is described in which a mechanical mode stirrer is used to provide a homogeneous electromagnetic field, while the heat input is controlled by the

Oliver Wiedenmann; Robert Ramakrishnan; Emre Kilic; Patrick Saal; Uwe Siart; Thomas F. Eibert

2012-01-01

240

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

241

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

242

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

Microsoft Academic Search

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

Bor-Tsuen Lin; Chun-Chih Kuo

2011-01-01

243

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

244

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

245

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

246

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

247

Accuracy of a Removable Die-Dowel Pin Technique  

Microsoft Academic Search

Stone working casts with removable dies with metal dowel pins were constructed from impressions of a master die to sim. ulate a quadrant cast of a three unit fixed partial denture. Measurements indicated that a small horizontal and a greater vertical shift occurred with the repositioned die.

Walter Dilts; Arlon Podshadley; Ernest Ellison; Robert Neiman

1971-01-01

248

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

PubMed

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

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

2009-06-01

249

A die-scale micromachining process for bulk PZT and its application to in-plane actuators  

Microsoft Academic Search

Bulk ceramics (including PZT) are important materials for electronic and microsystem packaging or device applications, but they are usually difficult to pattern lithographically. A fabrication process combining lithography, electroplating, batch mode micro electro-discharge machining (?EDM) and batch mode micro ultrasonic machining (?USM), LEEDUS, has been developed to provide die-scale pattern transfer capability from lithographic masks onto ceramics, glass or other

Tao Li; Yogesh B. Gianchandani

2005-01-01

250

Flow impact on cast ingots  

Microsoft Academic Search

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

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

2005-01-01

251

Rapid casting solutions: a review  

Microsoft Academic Search

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

Munish Chhabra; Rupinder Singh

2011-01-01

252

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

NASA Astrophysics Data System (ADS)

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

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

2006-12-01

253

Application of process modeling to improve the competitiveness of investment castings  

NASA Astrophysics Data System (ADS)

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

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

1996-03-01

254

Application of fuzzy logic control for continuous casting mold level control  

Microsoft Academic Search

This paper deals with the problem of molten metal level control in continuous casting. Under normal circumstances, proportional integral derivative (PID) control performs quite well, but abnormal conditions (in particular nozzle clogging\\/unclogging) require manual intervention. Indeed, when the flow of matter into the mold increases suddenly, the PID controller is not always able to prevent large level variations that can

Michel Dussud; Sylvie Galichet; Laurent P. Foulloy

1998-01-01

255

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...

256

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

257

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

258

Die-attach for high-temperature applications using fineplacer-pressure-sintering (FPS)  

Microsoft Academic Search

A new joining technique called “Fineplacer-Pressure-Sintering” (FPS) for die-attach of small electronic components (e.g. LEDs and photodiodes) is described. Using a modified Flip Chip Bonder, bare dies could be bonded onto substrates with high positioning accuracy. For the FPS process a 50 tons press, which is conventionally used for pressure sintering, is no longer required. Very high average shear strengths

Julian Kahler; Nicolas Heuck; Gerhard Palm; Andrej Stranz; Andreas Waag; Erwin Peiner

2010-01-01

259

Cu wire bonding with Cu BSOB for SiP & stacked die application: Challenges & solutions  

Microsoft Academic Search

In this paper, key challenges for copper (Cu) BSOB wire bonding process and its solutions are discussed. Cu wire bonding is an alternative interconnection technology for gold (Au) wire bonding. Cu wire is attractive because of its cost, electrical and thermo-mechanical properties. BSOB is the short form of bond-stitch-on-ball. It is used on devices that require die-die wire bonding in

B. Senthil Kumar; Mohandass Sivakumar; Chua Choon Wee; Li Ming; Keng Yew; J. Song

2009-01-01

260

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

NASA Astrophysics Data System (ADS)

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

Boro?, ?.; Tchórz, A.

2010-02-01

261

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

262

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

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

263

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

264

Three-dimensional probabilistic simulation of solidification grain structures: Application to superalloy precision castings  

Microsoft Academic Search

A two-dimensional (2-D) probabilistic model, previously developed for the prediction of microstructure formation in solidification\\u000a processes, is applied to thin section superalloy precision castings. Based upon an assumption of uniform temperature across\\u000a the section of the plate, the model takes into account the heterogeneous nucleation which might occur at the mold wall and\\u000a in the bulk of the liquid. The

Ch.-A. Gandin; M. Rappaz; R. Tintillier

1993-01-01

265

A high efficiency, compact size, single die tri-mode PAM for 3G\\/4G handset applications  

Microsoft Academic Search

A set of high level integration, compact size (1.3mm×1.1mm), single die, tri-mode power amplifiers are developed using Bi-FET (HBT+E\\/D-PHEMT) technology for 3G & 4G mobile handset applications. They have high efficiency optimized at mid and low power modes for long battery life. They also have excellent performance over voltage and over temperature (?40C to +85C). These tri-mode PAMs cover 3GPP

Cindy Yuen; Duc Chu; Kirk Laursen; Yinyin Zhao; Xiaoming Ji; Heinz Do; Yi-Ching Pao

2011-01-01

266

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

267

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

268

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

269

Grease for Casting Aluminum Alloys under Pressure.  

National Technical Information Service (NTIS)

A grease is described for use with die casting molds and adjacent hot parts of casting machines consisting of an oxidized petrolatum (containing smaller than or equal to 16% hydroxy acids) base material aluminum powder 1.5-1.7, flaky graphite 0.5-3.0, and...

A. I. Dintses G. B. Solomonik N. N. Belousov R. N. Osher T. M. Komissarova

1972-01-01

270

Sensitivity comparison of fast integrated die-to-die T+R pattern inspection, standard database inspection, and STARlight2 contamination mode for application in mask production  

NASA Astrophysics Data System (ADS)

'Fast Integrated Die-to-Die T+R' pattern inspection (DDTR), reflected tritone database inspection (DBRt) and STARlight2 TM (SL2) contamination inspection are employed by mask makers in order to detect pattern defects and contamination defects on photomasks for in process inspection steps. In this paper we compare the detection capabilities of these modes on real production masks with a representative set of contamination and pattern defects. Currently, SL2 inspection is used to find contamination defects and die-to-die and die-to-database are used for pattern defects. In this paper we will show that the new introduced 'Fast Integrated Die-to-Die T+R' pattern inspection (DDTR)1 in combination with the DBRt can be used in production environment, instead of SL2 without any loss in the sensitivity. During the study, we collected and analyzed inspection data on critical layers such as lines & spaces and contact holes. Besides, performance of the modes on product plates characterization was done using a test mask with programmed defects.

Schmalfuss, Heiko; Schulmeyer, Thomas; Heumann, Jan; Lang, Michael; Sier, Jean-Paul

2007-10-01

271

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

272

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

NASA Technical Reports Server (NTRS)

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

Lee, J. A.

1998-01-01

273

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

274

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

275

78 FR 38682 - Information Collection; Application for Payment of Amounts Due Persons Who Have Died, Disappeared...  

Federal Register 2010, 2011, 2012, 2013

...producer are entitled to receive payments earned by a producer who dies, disappears...Abstract: Persons desiring to claim payments earned, but not yet paid to a person who has...beneficiaries or others who claim payment that was earned, but not yet paid to the person who...

2013-06-27

276

Application of a heuristic search technique for the improvement of spray zones cooling conditions in continuously cast steel billets  

Microsoft Academic Search

The process of casting occupies an important place in the metallurgical industry, and the entire world of the metal user. In the past, the ingot casting–rolling (slabbing, blooming, or billeting) process was commonly used. The continuous casting process has largely replaced this earlier method because of the inherent advantages of energy savings, enhanced productivity, higher yield and reduced costs. However,

N. Cheung; C. A. Santos; J. A. Spim; A. Garcia

2006-01-01

277

Machine Casting of Ferrous Alloys.  

National Technical Information Service (NTIS)

Due to the lack of economic permanent die materials for use in Hipocasting ferrous alloys, three innovative approaches for creating a mold cavity for use in machine casting of ferrous alloys were explored. They were: use of liquid metal cooling of a thin ...

G. D. Chandley G. Scholl

1975-01-01

278

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

NASA Astrophysics Data System (ADS)

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

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

1994-11-01

279

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

280

Die-away kinetics of aerosolized bacteria from sprinkler application of wastewater.  

PubMed Central

A methodology for estimating, under field conditions, the microbial die-away constant (lambda) is presented. This constant may be used in predicting the aerosolized pathogenic microorganism concentrations downwind from a wastewater spray or aeration site by means of modified atmospheric diffusion equations. The mean lambda of Escherichia coli for very early morning runs was 8.8 X 10(-3)s-1, and that for afternoon runs was 6.6 X 10(-2)s-1.

Teltsch, B; Shuval, H I; Tadmor, J

1980-01-01

281

LOW-PRESSURE CASTING OF LM25 (Al7Si0.3  Mg) ALUMINIUM ALLOY  

Microsoft Academic Search

Low-pressure casting (LPC) is a specialized process for producing thin component castings of ferrous and nonferrous metals and alloys. This process has fewer casting and mold-filling problems than conventional processes like gravity and pressure-die casting, thus giving rise to castings with good mechanical properties. In the present study, LM25 (Al-7Si-0.3  Mg) aluminium alloy castings have been produced using indigenously designed

A. Srinivasan; U. T. S. Pillai; V. John; B. C. Pai

2005-01-01

282

A review of physical and kinetic models of thermal degradation of expanded polystyrene foam and their application to the lost foam casting process  

Microsoft Academic Search

A review of the literature was conducted in search of an appropriate kinetic model applicable to the polystyrene foam decomposition phenomena encountered in the lost foam casting process. A brief review of the models describing the physical process of foam degradation is also presented. During this investigation, various kinetic models describing polystyrene thermal decomposition in the plastics recycling process have

Pravin Kannan; Joseph J. Biernacki; Donald P. Visco Jr.

2007-01-01

283

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

284

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

PubMed

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

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

2012-09-01

285

Application of high-strength cast iron for the production of parts of refrigerator and compressor machines  

Microsoft Academic Search

High-strength spheroidal graphite iron surpasses gray lamellar iron in density. Whereas in highstrength cast iron, the graphite inclusions are isolated from each other and their growth, in the eutectic cooling process, occurs by diffusion of carbon from the liquid metal through austenitic outgrowths, in gray cast iron, the growth of lamellar graphite occurs in direct contact with the liquid. In

M. V. Voloshchenko; N. B. Pokrovskaya; G. G. Shipunov; A. P. Pshennyi; V. Ya. Kucher

1971-01-01

286

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

287

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

288

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

289

Application of finite element method and artificial neural network to the die design of radial forging processes  

Microsoft Academic Search

This investigation adopts the finite element method (FEM) and the artificial neural network (ANN) to plan the radial forging of work-hardened materials to yield the optimal designed die. The process parameters considered herein are die corner radius (R), ring gap height (H), friction factor (m), work-hardening coefficient (n), gap between the billet and die (c) and the punch load (f).

Su-Hai Hsiang; Huey-Lin Ho

2004-01-01

290

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

291

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

292

Paper Casting.  

ERIC Educational Resources Information Center

Describes an art project, based on the work of artist Chew Teng Beng, in the molding of wet paper on a plaster cast to create embossed paper designs. The values of such a project are outlined, including a note that its tactile approach makes it suitable to visually handicapped students. (SJL)

Arrasjid, Dorine A.

1980-01-01

293

Die Fadeninjektion  

NASA Astrophysics Data System (ADS)

Die Fadeninjektion ist eine in Entwicklung befindliche neue, minimal invasive Implantationstechnik für metabolisch induktive Werkstoffe. Sie schafft eine Möglichkeit, offenporige Strukturen nach Injektion durch einen dünnen Kanal in den Körper zu implantieren. Der Injektionsvorgang ist schematisch in Abb. 45.1 dargestellt. Der Faden wird während der Injektion vom Trägerfluid über Reibungs- und Druckkräfte kontinuierlich durch den Injektionskanal vorgeschoben und legt sich als makroskopisch offenporige Struktur in der Form eines Fadenknäuels am Injektionsort ab. Voraussetzung für die Injizierbarkeit ist eine genügend kleine Biegesteifigkeit des Fadens, damit sich eine Knäuelstruktur durch die zufälligen Windungen des Fadens überhaupt ausbilden kann. Beispiele von Implantatstrukturen zeigt Abb. 45.1.

Lüscher, Patrik; Wintermantel, Erich

294

Assisted dying.  

PubMed

The Royal College of Physicians took a neutral position on the House of Lords Assisted Dying for the Terminally Ill Bill. While modern palliative care and the hospice approach have greatly reduced terminal suffering, they do not always achieve total relief of distressing symptoms--he majority of dying patients and their families probably do not receive optimal terminal care. In this article I try to rebut the common arguments against assisted dying and add some arguments in favour. I suggest that on this issue the medical professions are out of tune with majority public opinion. PMID:16521360

Hoffenberg, Raymond

2006-01-01

295

DIE WAARDE VAN DIE RETORIKA BY DIE BESTUDERING VAN ADVERTENSIES  

Microsoft Academic Search

Hoewel die retorika bykans 26 eeue oud is, word die relevansie daarvan vir ons eie tyd toenemend besef soos blyk uit die kragtige en omvattende “rhetorical (re)turn” die afgelope dekades in Amerika en elders. Die retorika verskqf inderdaad ook in ons tyd steeds 'n sleutel tot die wyse waarop mense dink, argumenteer en oorreed, aangesien hedendaagse sprekers en skrywers, gebore

Dorothea van Zyl

1998-01-01

296

Statistical Analysis of Modified Drucker-Prager Cap Model Parameters for Application to Modeling Die Compaction  

Microsoft Academic Search

Many soil constitutive models have been studied for their applicability to the powder compaction simulation process. However most of the parameters to define these models are determined by high- pressure hydrostatic compression and triaxial tests requiring a high pressure setup. This limits the industrial usability of these simulations to determine density gradients in compacted powder parts for different powders. In

Gautam S. Wagle; Renata S. Engel; Ravi Bollina; Randall M. German

297

Casting methods  

DOEpatents

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

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

2012-12-18

298

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

299

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

300

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

301

Casting materials  

SciTech Connect

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

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

2011-06-14

302

The effect of casting temperature on the properties of squeeze cast aluminium and zinc alloys  

Microsoft Academic Search

Gravity casting and squeeze casting were carried out on an aluminium alloy with 13.5% silicon and a zinc alloy with 4.6% aluminium with different temperatures, 660, 690 and 720°C for the former and 440, 460 and 480°C for the latter. A top-loading crucible furnace was used to melt the alloys. The die-preheat temperatures used were 200–220°C for the aluminium alloy

L. J. Yang

2003-01-01

303

Melt cast processed (MCP)-BSCCO 2212 tubes for power applications up to 10 kA  

Microsoft Academic Search

The Melt Cast process (MCP) is highly flexible to manufacture BSCCO 2212 bulk parts in a large variety of shapes and dimensions. MCP also allows the integration of current contacts during the fabrication process thus leading to HTS parts which can directly be integrated into electrotechnical devices, The ease of mechanical treatment of the material by machining methods offers additional

J. Bock; S. Elschner; P. Herrmann

1995-01-01

304

Casting the Spirit: A Handmade Legacy  

Microsoft Academic Search

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 powerful representations that

Mona Rutenberg

2008-01-01

305

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

306

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

PubMed

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

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

2013-09-01

307

Wettability of elastomeric impression materials and voids in gypsum casts.  

PubMed

Numerous factors are involved in making an accurate void-free dental artificial stone cast or die. The relationship of the wettability of an elastomeric impression material and its interaction with the gypsum slurry is an important factor. This study examined the relative "pourability" of several impression materials by counting the number of resultant voids in artificial stone casts containing 48 point angles. Those elastomers that exhibited the lowest contact angle with water produced artificial stone casts with the fewest voids. Surfactants applied to the impression material significantly reduced the number of voids in artificial stone casts, as did modified elastomers designated by the manufacturer as hydrophilic. PMID:1774689

Cullen, D R; Mikesell, J W; Sandrik, J L

1991-08-01

308

Thin Wall Iron Castings  

SciTech Connect

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

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

2001-10-31

309

CAST Project. Guidelines for the Application of the Regulation (EC) 2023/2006 to Supply Chain of Materials and Articles Intended to Come into Contact with Food. (Progetto CAST. Linee Guida per l'applicazione del Regolamento 2023/2006/CE alla Filiera di Produzione dei Materiali e Oggetti Destinati a Venire in Contatto con gli Alimenti.)  

National Technical Information Service (NTIS)

In the frame of the CAST Project (Contatto Alimentare Sicurezza e Tecnologia) general and specific guidelines for the application of the Regulation (EC) 2023/2006 on good manufacturing practice in the supply chain of materials and articles intended to com...

A. Maggio A. Maini G. Padula M. Denaroviani M. R. Milana R. Feliciani

2011-01-01

310

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

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

311

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

312

Everyone dies.  

PubMed

It's not unusual to be dispatched to one problem and discover something completely different when you arrive. Patients and family members will tell dispatch what they feel is the problem, and dispatch, without the benefit of being on scene, can only pass along the complaint as it was given to them. Upon arrival back at base, the attending paramedic in this case was asking himself questions like, "What if I had done this differently?" and "Did I miss something?" At the conclusion of every patient interaction, there is an opportunity for EMS to review its actions and [table: see text] change its approach to similar cases in the future. The benefit of public-safety agencies providing service in nonemergent situations is the opportunity to "practice" for true crisis incidents. This case, however, did not present many opportunities to improve care or change the outcome. The paramedic's assessment identified the need for the patient to be transported immediately. Immediate packaging of the patient, intubation and pacing were performed on scene--you known this crew was moving. The ED physician concurred that this was a "load and go" situation. The crew is to be commended for taking charge of a critical situation and performing in an expeditious manner. Oxygen, pacing, i.v. and meds were all given in a timely fashion. Unfortunately, this patient's cancer had progressed to a critical point, and the patient was not going to survive even with optimal care. This EMS crew unfortunately walked into an end-of-life event. Despite their best efforts (a total on-scene time of seven minutes and a five-minute transport) and performing every function flawlessly, this patient still died. This patient was given excellent medical service, but perhaps more important, at his critical moment, was in the presence of people who cared. One of the first things we learn in EMS is that people die. Sometimes our job is simply to provide comfort, relieve suffering and communicate with the survivors. Since all humans must die, it is just as important for us to service their needs at that moment in time. From there, we move on to the next call. PMID:12841033

Weinmann, Michael

2003-06-01

313

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

314

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

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

315

Rapid tooling of die DMLS inserts for shoot-squeeze moulding (DISA) system  

Microsoft Academic Search

The rapid tooling (RT) technology applied to die-plates for moulding in DISAmatic© cast line was investigated. Die inserts made by RT direct techniques such as: direct metal laser sintering (DMLS); stereolithography (SL); laminated object manufacturing (LOM); and selective laser sintering of polymer powder (SLS-P), are compared. Mechanical properties and accuracy are critical on choosing the rapid tooling die inserts as

J. C. Ferreira

2004-01-01

316

Sensor-based assessment of cast placement and removal.  

PubMed

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

Maag, Anne-Lise D; Laufer, Shlomi; Kwan, Calvin; Cohen, Elaine R; Lenhart, Rachel L; Stork, Natalie C; Halanski, Matthew A; Pugh, Carla M

2014-01-01

317

Sensor-Based Assessment of Cast Placement and Removal  

PubMed Central

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

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

2014-01-01

318

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

319

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

320

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

321

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

2012-11-01

322

High Performance Castings.  

National Technical Information Service (NTIS)

The report delineates the factors influencing the characteristics, design, and properties of high-performance castings and the outstanding problems that must be resolved to enhance the reliability and use of these castings. It suggests a number of program...

1972-01-01

323

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

SciTech Connect

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

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

2005-01-30

324

Die Innervation des Dünndarmes  

Microsoft Academic Search

Zusammenfassung Bei den mit Curare vergifteten Tieren wird durch die Reizung der Medulla oblongata die Peristaltik und der Tonus des Dünndarmes vermindert. Diese Sympathicuswirkung kann jedoch durch die Durchtrennung des Rückenmarkes unterhalb der Medulla oblongata oder durch die Nicotinisierung des Ganglion coeliacum ausgeschaltet werden. Reizt man die Medulla oblongata nach einem dieser Eingriffe, so kommt es zu einer Steigerung des

B. v. Issekutz

1934-01-01

325

Vacuum casting of thick polymeric films  

NASA Technical Reports Server (NTRS)

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

Cuddihy, E. F.; Moacanin, J.

1979-01-01

326

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

327

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

328

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

329

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

NASA Astrophysics Data System (ADS)

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

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

330

Casting and Molding  

NSDL National Science Digital Library

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

Blind, Perkins S.

2012-06-26

331

Advanced Cast Aluminum Alloys.  

National Technical Information Service (NTIS)

A recent advancement in cast aluminum alloys has demonstrated that complex shapes can be cast from a microalloyed Al-Cu alloy in dry sand molds with chills and that these castings can be heat treated to produce mechanical and physical properties nearly co...

A. P. Druschitz J. Griffin

2009-01-01

332

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

SciTech Connect

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

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

1998-01-31

333

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

334

Materials processing threshold report: 2. Use of low gravity for cast iron process development  

NASA Technical Reports Server (NTRS)

Potential applications of a low gravity environment of interest to the commercial producers of cast iron were assessed to determine whether low gravity conditions offer potential opportunities to producers for improving cast iron properties and expanding the use of cast irons. The assessment is limited to the gray and nodular types of iron, however, the findings are applicable to all cast irons. The potential advantages accrued through low gravity experiments with cast irons are described.

Frankhouser, W. L.

1980-01-01

335

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

DOEpatents

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

Stoddard, Nathan G. (Gettysburg, PA)

2011-11-01

336

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

337

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

338

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

NASA Astrophysics Data System (ADS)

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

Zhang, Qiang; Masoumi, Mohsen; Hu, Henry

2012-01-01

339

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

340

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

341

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...

342

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...

343

ESMART Subtask 5.8: Mechanical Performance of Dies. Final Technical Report.  

National Technical Information Service (NTIS)

As a net shape process, die casting is intrinsically efficient and improvements in energy efficiency are strongly dependent on design and process improvements that reduce scrap rates so that more of the total consumed energy goes into acceptable, usable c...

A. Delgado-Garza A. Ragab K. Murugesan K. K. Bamoradian R. A. Miller

2011-01-01

344

Die Oogenese der Tipuliden  

Microsoft Academic Search

1.Es wird die Oogenese von 10 Arten der Familie Tipulidae (Nematocera, Diptera) beschrieben. Von Pales crocata, Tipula oleracea, T. caesia und T. lateralis wurden die Oogonienteilungen und Reifeteilungen im Ei; von P. scurra, P. quadristriata, T. pruinosa und T. marginata die Oogonienteilungen; von P. pratensis und T. paludosa die RT I im Ei untersucht.2.Der Chromosomenbestand von Tipula caesia und T.

Klaus Bayreuther

1955-01-01

345

Anxiety reaction in children during removal of their plaster cast with a saw  

Microsoft Academic Search

e have had experience of an 18-month-old boy with a cardiomyopathy who died a few minutes after removal of his cast with a saw, apparently from a malignant cardiac arrhythmia triggered by anxiety. We therefore examined the anxiety reaction to this method of removal of a plaster cast in 20 healthy children; ten were provided with hearing protectors and ten

K. Katz; R. Fogelman; J. Attias; E. Baron; M. Soudry

2001-01-01

346

Improving Metal Casting Process  

NASA Technical Reports Server (NTRS)

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

1998-01-01

347

Die drool and die drool theory  

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

348

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

349

Metallic Fuel Casting Development and Parameter Optimization Simulations  

SciTech Connect

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

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

2013-03-01

350

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

2012-07-01

351

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

352

A comparative evaluation of linear dimensional accuracy of the dies obtained using three conceptually different die systems in the fabrication of implant prosthesis: An in vitro study.  

PubMed

Statement of Problem: Given that meticulous implant prosthodontic procedures are recommended to obtain the best possible intraoral fit, the die systems used for multi implant casts warrant further investigation. Die stone expansion and errors introduced by removable die casts may exceed the accuracy required for the passive fit of implant prosthesis. Purpose: The purpose of the study was to evaluate the linear dimensional accuracy between the implant master die and three conceptually different die systems such as Pindex system, Accu-trac precision die system, and Conventional brass dowel pin system. Materials and Methods: Thirty impressions of implant master die were made with polyether impression material. Ten experimental implant casts were fabricated for each of the three different die systems tested: Accu-trac precision die tray system, Pindex system, and conventional brass dowel pin system. The solid experimental casts were sectioned and then removed from the die system 30 times. Linear distances between all six possible distances were measured from one centre of the transfer coping to the other, using a co-ordinate measuring machine in millimeters up to accuracy of 0.5 microns. Data were tabulated and statistically analyzed by Binomial non parametric test using SPSS version 15. Results: Significant differences were found for distance A-B (P = 0.002), A-C ( P = 0.002), A-D (P value = 0.002), and B-D ( P = 0.021) in Conventional Dowel pin system however for Accu-trac precision die tray system, it was significant only for distance A-D (P = 0.002) but for Pindex system it was non-significant for all the distances measured. Conclusion: Within the limitations of this study, use of Pindex system is recommended when sectioned dies are needed for a multi implant retained prosthesis. PMID:24992851

Ahmad, Manawar; Balakrishnan, Dhanasekar; Narayan, Aparna Ichangod

2014-01-01

353

Abrasion wear behaviour of alloyed and chilled cast irons  

Microsoft Academic Search

High-chromium white cast irons are widely used in a variety of applications that require high wear resistance. This outstanding performance is due to the presence of large amounts of chromium carbides which exhibit high hardness. However, for wear-resistant applications exposed to impact, ductile cast iron is a candidate material due to its good wear behaviour, reduced brittleness and lower production

L. Ribeiro; A. Barbosa; F. Viana; A. Monteiro Baptista; C. Dias; C. A. Ribeiro

2011-01-01

354

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

NASA Technical Reports Server (NTRS)

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

Cooper, K. G.; Wells, D.

2000-01-01

355

Machine Casting of Ferrous Alloys.  

National Technical Information Service (NTIS)

The general purpose of the first six months' work was to identify techniques which will produce sound castings in reusable chill molds - techniques which are compatible with an automated machine casting process. To do this, castings made in permanent chil...

M. F. X. Gigliotti

1973-01-01

356

Thermal fatigue of materials for die-casting tooling  

Microsoft Academic Search

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

D. Klob?ar; J. Tušek; B. Taljat

2008-01-01

357

Casting Footprints for Eternity  

NASA Technical Reports Server (NTRS)

Apollo 11 Astronaut Buzz Aldrin has his footprints casted during the dedication ceremony of the rocket fountain at Building 4200 at Marshall Space Flight Center. The casts of Aldrin's footprints will be placed in the newly constructed Von Braun courtyard representing the accomplishments of the Apollo 11 lunar landing.

1999-01-01

358

Computer cast blast modelling  

Microsoft Academic Search

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

S. Chung; M. McGill; D. S. Preece

1994-01-01

359

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

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

Die Entstehung der Erde  

Microsoft Academic Search

\\u000a Die Problematik eines Weltbildes, sich also ein „Bild von der Welt“ zu machen, fängt an mit der Frage, was man unter der „Welt“\\u000a eigentlich versteht. Unter den verschiedenen wissenschaftlichen Teildisziplinen wird die Antwort zwangsläufig sehr unterschiedlich\\u000a ausfallen, was man an den Beiträgen zu diesem Band unschwer erkennen wird. Für den Geowissenschaftler scheint die Antwort einfach und naheliegend: Geos, griech. die

Mario Trieloff

362

Dying in acute care  

Microsoft Academic Search

The demography of dying in Australia, as in other developed countries, has shifted dramatically in a single generation. Cause of death, place of death and mode of dying are all unrecognisable to the generation currently facing death. The fastest growing causes of death in Australia are dementia (now third commonest) and diabetes (sixth), two thirds die in acute care, most

P Saul

2011-01-01

363

Die Coin Experiment  

NSDL National Science Digital Library

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

Siegrist, Kyle

364

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

365

A study of the interface reaction mechanism between molten aluminum and ferrous die materials  

NASA Astrophysics Data System (ADS)

One of the main concerns in the aluminum die casting industry is the problem of die soldering. Die soldering is when aluminum sticks to the surface of the die material, mostly H-13 tool steel, and remains there after ejection of the cast part. In recent times, this defect has posed a major concern because of the notable decrease in productivity and efficiency of casting operations. Due to the high affinity that aluminum has for iron, a vigorous physio-chemical reaction occurs at the die/molten metal interface when aluminum melt comes in direct contact with the ferrous die. This reaction results in the immediate formation of a series of iron-aluminum-silicon intermetallic compounds over the die surface and eventually the cast metal sticks to this intermetallic layer. The aim of this work is to illustrate and quantify the effect of the various die casting parameters, which enhance die soldering, and subsequently alleviate or mitigate the defect. The primary objective was to establish the mechanism of die soldering and other aluminum/ferrous die interface reactions. Two sets of experimental work was carried out---L-9 Taguchi Matrix, L-16 Taguchi matrix. These experiments quantified the effect of various critical casting parameters that influenced the molten aluminum/ferrous die interface reactions. In addition critical diffusion couple experiments between aluminum 380 alloy and H-13 tool steel was carried out to establish the reaction mechanisms between the two. Based on the analysis of the results from the above-mentioned set of experiments, a mechanism for the molten aluminum/ferrous die interface reactions was presented. The interaction is a diffusion controlled process consisting of six stages. Stage I is the erosion of the die material by the aluminum melt to form pits on the surface. In Stage II, binary iron-aluminum intermetallic compounds grow on these pits. Stages II through VI deals with the different stages of development of these intermetallic phase layers due to the diffusion of iron atoms from the die surface into the aluminum melt, and the subsequent soldering of aluminum alloy on these layers of intermetallic compounds, respectively. Subsequently, recommendations were put forth to alleviate the reaction between aluminum and ferrous die.

Shankar, Sumanth

366

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

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

INTERIOR VIEW WITH LARGE PIPE CASTING MACHINE CASTING A 48' PIPE OPERATOR SPRAYING A POWDER TO HELP SOLIDIFY THE PIPE BEING CENTRIFUGALLY CAST. - United States Pipe & Foundry Company Plant, Pipe Casting & Testing Area, 2023 St. Louis Avenue at I-20/59, Bessemer, Jefferson County, AL

367

Optimum cast plan for steelmaking-continuous casting production scheduling  

Microsoft Academic Search

A planning method of cast for steelmaking continuous casting production scheduling in CIMS is studied. The cast plan model is established. An adaptive operator genetic algorithm is proposed to solve the optimum cast plan problem. The computation with practical data shows that the model and the solving method are very effective.

Yuncan Xue; Qiwen Yang; Huihe Shao

2004-01-01

368

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

369

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

370

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

371

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

372

Concrete Casting Machine.  

National Technical Information Service (NTIS)

The machine is for casting, on a production line basis, articulated concrete revetment mats employed to protect riverbanks and flood control levees from hydraulic erosion. The apparatus includes a moving conveyor system which carries flat pallets to a cas...

J. I. Boswell T. Burks G. F. Dixon G. S. Lee

1964-01-01

373

Cast changes: synthetic versus plaster.  

PubMed

A review of the changes in casting since the introduction of improved synthetic casting materials in the 1970s is presented. There is very little in the literature on nursing implications regarding the newer casting materials. Improvements in synthetic materials used in the casting of children include a fiberglass-free, latex-free casting polymer, with child-friendly prints now available. Though the use of synthetic casting predominates the market, plaster of Paris is still the mainstay for serial casting and casting requiring superior moldability and conformability. The advantages and disadvantages of synthetic and plaster of Paris casting, as well as nursing care of the child in each type of cast are summarized. PMID:9282058

Adkins, L M

1997-01-01

374

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

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 alcogel which occurs during the drying step of supercritical extraction of solvent.

Poco, John F. (Livermore, CA)

1993-01-01

376

Bence Jones Cast Nephropathy  

Microsoft Academic Search

Patients with Bence Jones cast nephropathy usually present with acute renal failure (less commonly with chronic renal failure)\\u000a and Bence Jones proteinuria. It has been known for many years that intravenous radiocontrast media, dehydration, infections,\\u000a and the use of nonsteroidal antiin- fl ammatory drugs may induce the precipitation of renal tubular light chain casts and\\u000a result in acute renal failure,

Arthur H. Cohen

377

A Winning Cast  

NASA Technical Reports Server (NTRS)

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

2001-01-01

378

Über die Prothrombinzeitbestimmung im Menschenblut  

Microsoft Academic Search

Die Versuchsmethoden fiber die Gerinmmg des Blutes haben sieh in den letzten Jahren meistens in Zusammenhang mit den zahlreiehen Studien fiber die K-Avitaminose und fiber die Hypoprothrombin\\/ ~mien, welche an diese Avitaminose gebunden und nicht gebunden sind, entwickelt. Deshalb gewannen neben den verschiedenen Methoden ffir die Messung der Spontangerinnung szeit, die immer noch sehr wiehtig ffir alas Studium der Gerinnungsprozes

Bernardino Rovatti

1942-01-01

379

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

380

Viability changes: Microbiological analysis of dental casts  

PubMed Central

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

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

2014-01-01

381

Viability changes: Microbiological analysis of dental casts.  

PubMed

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

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

2014-01-01

382

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

383

Reaction synthesis of carbide-reinforced cast iron  

Microsoft Academic Search

Cast irons have found widespread uses as a result of their comparative low cost and their diversity of engineering properties. The low coefficient of friction of grey cast iron has led to its use in applications involving sliding surfaces such as piston rings, cylinder bores and brake discs in the automotive industry. Good sliding wear resistance is therefore one of

A. Chrysanthou; N. W. Davies; J. Li; P. Tsakiropoulos; O. S. Chinyamakobvu

1996-01-01

384

Control design and implementation in continuous steel casting  

Microsoft Academic Search

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

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

1995-01-01

385

Ultrasonic detection of heat fronts in continuously cast steel product  

Microsoft Academic Search

Measurement of process parameters of continuously cast hot steel can play an important role in assessing the state of the casting process. One quantity of crucial importance is temperature, currently restricted to surface measurements using conventional optical pyrometers. A more useful quantity is internal temperature, and the authors discuss the application of ultrasonic time-of-flight methods to the harsh conditions of

Chris Baharis; Robert Cornish

1991-01-01

386

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

EPA Science Inventory

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

387

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

EPA Science Inventory

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

388

Reinraumtechnik für die Medizintechnik  

NASA Astrophysics Data System (ADS)

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

Petek, Max; Jungbluth, Martin; Krampe, Erhard

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

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

391

Quartz ceramic nozzles for casting steel on continuous casting plant  

Microsoft Academic Search

Conclusions A technology was developed for making steel casting nozzles for the continuous casting of steel with different versions of lateral input of metal into the crystallizer. In laboratory conditions we made nozzles 600–650 mm long.

R. S. Churakova; E. P. Fedorova; Yu. A. Polonskii; E. I. Ermolaeva; A. M. Pozhivanov; N. D. Karpov

1972-01-01

392

Death and Dying  

ERIC Educational Resources Information Center

The author discusses death and the dying process, the psychological needs of a person who is faced with his or her imminent death, and the five stages of emotional response through which a dying person goes in coping with the fact of death. (MJB)

Hafen, Brent Q.

1977-01-01

393

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 ...

394

A new casting defect healing technology  

SciTech Connect

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

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

1997-01-01

395

Composites for Advanced Space Transportation Systems (CASTS)  

NASA Technical Reports Server (NTRS)

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

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

1979-01-01

396

TiC reinforced cast chromium steels  

SciTech Connect

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

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

2003-11-01

397

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

398

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

399

Pressure Casting in Investment Molds.  

National Technical Information Service (NTIS)

A study was made of methods for pressure casting nonferrous alloys into investment molds. The experimental methods were compared with standard suction casting practices. The best method studied was the direct pressure diaphragm method. By this method, met...

S. Lipson F. Ripkin

1964-01-01

400

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

401

Sealing micropores in thin castings  

NASA Technical Reports Server (NTRS)

Microscopic pores in thin-walled aluminum castings are sealed by impregnation pretreatment. Technique was developed for investment castings used in hermetically sealed chassic for electronic circuitry. Excessively high leakage rates were previously measured in some chassis.

Mersereau, G. A.; Nitzschke, G. O.; Ochs, H. L.; Sutch, F. S.

1981-01-01

402

Adapt or die?  

PubMed

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

Visser, S S; Nel, A H

1996-12-01

403

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

SciTech Connect

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

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

2009-09-15

404

Casting Of Multilayer Ceramic Tapes  

NASA Technical Reports Server (NTRS)

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

Collins, Earl R., Jr.

1991-01-01

405

BIMETALLIC CASTING. Final Report  

Microsoft Academic Search

Uranium and Zr were bonded by melting the two metals in contact with one ; another in a bimetallic casting process. Tensile tests of specimens containing ; the original zone of interface between the two metals showed that all failures ; were at locations other than the interface. The coefficients obtained for ; diffusion between molten U and molten Zr

T. Poole; D. Krashes

1962-01-01

406

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.

407

Mix/Cast Contamination Control  

NASA Technical Reports Server (NTRS)

Presented is a training handbook for Mix/Cast Contamination Control; a part of a series of training courses to qualify access to Mix/Cast facilities. Contents: List Contamination Control Requirements; Identify foreign objects debris (FOD), Control Areas and their guidelines; Describe environmental monitoring; List Contamination Control Initiatives; Describe concern for Controlled Materials; Identify FOD Controlled Areas in Mix/Cast.

Wallentine, M.

2005-01-01

408

Laser-Ultrasonic Inspection of MG\\/AL Castings  

Microsoft Academic Search

Laser-ultrasonics is used to assess the metallurgical bond between Mg\\/Al materials in die-cast Magnesium\\/Aluminum composite. The acoustic impedances of Mg, Al and air are such that the amplitude of ultrasonic echoes reflected back from a void is many times larger than the amplitude of those reflected back from a well-bonded interface. In addition, the polarity of echoes from a void

Alain Blouin; Daniel Lévesque; Jean-Pierre Monchalin; Eric Baril; Andreas Fischersworring-Bunk

2005-01-01

409

An experimental study on the energy absorption capacity of thin-walled castings  

Microsoft Academic Search

The energy absorption potential of high-pressure die cast (HPDC) components made of magnesium alloys AM20, AM50, AM60, AZ91 and the aluminium alloy A356 is investigated using a shear–bolt principle. Both quasi-static and dynamic tests have been performed. In addition, single cast plates of AM60 and A356 alloy with different thickness have been tested in order to investigate the effect of

Cato Dørum; Odd Sture Hopperstad; Odd-Geir Lademo; Magnus Langseth

2006-01-01

410

When a Student Dies.  

ERIC Educational Resources Information Center

Discusses a pedagogy for teaching middle school students how to grieve when one of their classmates dies. Considers the steps of the grieving process, and dealing with different types of death: murder, suicide, accidents, and illness. (JPB)

Lovelace, James; Thompson, Jen

2000-01-01

411

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

412

AMCC casting development, volume 2  

NASA Technical Reports Server (NTRS)

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

1995-01-01

413

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

SciTech Connect

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

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

2008-11-21

414

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.

415

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

416

Volume MLS ray casting.  

PubMed

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

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

2008-01-01

417

Über die Wirkung einiger lokaler Anästhetika auf die Lungengefäße  

Microsoft Academic Search

Zusammenfassung 1.Adrenalin in Mengen von 0,002–0,005 g in die Pulmonalarterie der isolierten Hundelunge injiziert, verursacht entweder Konstriktion oder — anscheinend seltener — Dilatation mit nachfolgender Konstriktion der Lungengefäße. Diese Unterschiedlichkeit der Wirkung besteht auch bei gleichem Druck. Die Adrenalinwirkung auf die Lungengefäße ist schwächer als die auf die Gefäße der übrigen Organe.2.Bariumchlorid, in 10%iger Lösung, ruft eine maximale Konstriktion der

Richard Schlesinger

1931-01-01

418

Die Faunenwende Perm\\/Trias  

Microsoft Academic Search

Zusammenfassung  Aufgrund der Diversitätsverteilung der Invertebraten im Phanerozoikum wird folgende These aufgestellt: Die Faunenwende Perm\\/Trias war kein katastrophales Aussterben sondern es entstanden weniger neue Arten. Dies wird durch einige Fallstudien untermauert, welche Aussterben und Neuauftreten im oberen Paläozoikum untersuchen. Ursache des verminderten Neuauftretens ist die mit dem Zusammendriften der Kontinente einhergehende Abnahme der Isolationsmöglichkeit neuer Arten. Die Wechselwirkungen verschiedener Umweltparameter sowie

Hansmartin Hüssner

1983-01-01

419

Study on the Low-looped Ability of Forward and Reverse Looping Methods of Gold Wire Ball Bonding for Stacked Die Package Application  

Microsoft Academic Search

The packaging technology is driving to lower loop height level with the developments of multiple level stacked die packages and multi-tiered IC packages. It is very important to find moderate low-looped method to achieve perfect bondability and low-looped ability. The effects of looping methods on the bondability and low-looped ability were studied and analyzed. The study results shows that the

Xiu-Lan Cheng; Yu-Cai Huang

2006-01-01

420

Die Mikrofossilien des jugoslawischen Perms  

Microsoft Academic Search

Zusammenfassung  Die Mikrofauma-und-flora der verschiedenen Stufen und Fazies des jugoslawischen Perms wird für die einzelnen Horizonte und\\u000a einige besonders reiche Fundpunkte in Fossil-Listen dargestellt. Die Fund-Horizonte sind die unteren, mittleren und oberen\\u000a Rattendorfer Schichten, derPseudofusulina-vulgaris-Zone entsprechende mittelpermische Schichten, die Trogkofel-Schichten, Neoschwagerinen-Schichten und die Schichten der Žažar-Stufe.\\u000a \\u000a Die Morphologie und Phylogenese einiger interessanter Kalkalgen und Fusuliniden des jugoslawischen Perms wird kurz erörtert.

Vanda Kochansky-Devidé

1964-01-01

421

Rapid machining of hardened AISI H13 and D2 moulds, dies and press tools  

Microsoft Academic Search

Tools and dies for the forging, die casting and plastics moulding industries are commonly made from AISI H13, heat treated to 48–52 HRC, while the press tool sector predominantly uses AISI D2 at a significantly higher hardness of 60–62 HRC. Over the last 10 years, the introduction of high speed end milling has enabled the direct manufacture of prismatic components

Helen Coldwell; Richard Woods; Martin Paul; Philip Koshy; Richard Dewes; David Aspinwall

2003-01-01

422

Effect of Applied Pressure and Nickel Coating on Microstructural Development in Continuous Carbon Fiber-Reinforced Aluminum Composites Fabricated by Squeeze Casting  

Microsoft Academic Search

Continuous carbon fiber reinforced aluminum composite samples were produced by squeeze casting method, under applied pressures of 30, 50, and 70 MPa. For production of samples, nickel coated and uncoated carbon fibers with a mean volume fraction of 40% were used. After making the fiber preforms, they were preheated and then were replaced in a casting die. Molten 2024 aluminum alloy

E. Hajjari; M. Divandari; H. Arabi

2011-01-01

423

Experiences of the dying.  

PubMed

It is often a mystery to us how we have come to know and believe in certain things. Beliefs are like guests who come up to a door. They come in only if the host opens it and invites them in. Otherwise they are turned away, unable to enter. LPNs/LVNs are invited to reflect on their experiences and expand their knowledge and beliefs. There is growing recognition that bedside talks of the dying, spirit travel and near-death events are real events for the people who experience them. LPNs/ LVNs are encouraged to expand their knowledge and beliefs about dying. PMID:23252027

Schoenbeck, Susan L

2011-01-01

424

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

425

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

426

Cast dielectric composite linear accelerator  

DOEpatents

A linear accelerator having cast dielectric composite layers integrally formed with conductor electrodes in a solventless fabrication process, with the cast dielectric composite preferably having a nanoparticle filler in an organic polymer such as a thermosetting resin. By incorporating this cast dielectric composite the dielectric constant of critical insulating layers of the transmission lines of the accelerator are increased while simultaneously maintaining high dielectric strengths for the accelerator.

Sanders, David M. (Livermore, CA) [Livermore, CA; Sampayan, Stephen (Manteca, CA) [Manteca, CA; Slenes, Kirk (Albuquerque, NM) [Albuquerque, NM; Stoller, H. M. (Albuquerque, NM) [Albuquerque, NM

2009-11-10

427

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

428

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

429

The use of artificial intelligence technique for the optimisation of process parameters used in the continuous casting of steel  

Microsoft Academic Search

The productivity and quality of a continuous caster depend mainly on process parameters, i.e. casting speed, casting temperature, steel composition and cleanliness of the melt, water flow rates in the different cooling zones, etc. This work presents the development of an algorithm, which incorporates heuristic search techniques for direct application in metallurgical industries, particularly those using continuous casting process for

Carlos A. Santos; Jaime A. Spim Jr; Maria C. F. Ierardi; Amauri Garcia

2002-01-01

430

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

431

Tool & Die Technician.  

ERIC Educational Resources Information Center

This document contains 23 units to consider for use in a tech prep competency profile for the occupation of tool and die technician. All the units listed will not necessarily apply to every situation or tech prep consortium, nor will all the competencies within each unit be appropriate. Several units appear within each specific occupation and…

Ohio State Univ., Columbus. Center on Education and Training for Employment.

432

When a Baby Dies.  

ERIC Educational Resources Information Center

Written especially for grieving mothers whose babies have died, this booklet offers an overview of stages and experiences through which bereaved parents commonly pass. Specifically, the text is intended to give comfort to bereaved parents, offer insight into the grieving process, and provide thoughts on leave-taking ceremonies. The first section…

Church, Martha Jo; And Others

433

Columnar to equiaxed transition in high Cr white iron castings  

SciTech Connect

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

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

1996-07-15

434

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

435

Advanced Line Die Forming Simulation Technology and Its Impact on Stamping Automotive Body Panels  

NASA Astrophysics Data System (ADS)

Line die forming simulation and validation create tremendous business values for automotive die developments and production stamping while they pose a great technological challenge to stamping CAE community. GM Manufacturing Engineering Die Center has developed an integrated line die analysis technology to validate die lines as a productionized business process. In this process, a finished stamping body panel can be streamline analyzed with required time, accuracy, and quality. This paper presents critical issues in line die analysis, discusses technical challenges in production applications and software development, and finally demonstrates the impact of line die forming simulation and validations on automotive body styling and tooling developments.

Zhang, Jimmy; Wang, Chuantao; Xu, Siguang; Joshi, Ramesh; Goan, Norman

2005-08-01

436

Effect of Si, Cu and Fe on mechanical properties of cast semi-solid 206 alloys  

Microsoft Academic Search

The development of a modified 206 alloy whose composition was optimized to minimize hot tearing during semi-solid forming was reported. The effect of varying silicon, copper and iron contents was investigated using a design of experiment (DOE) approach. Semi-solid slurries were prepared using the SEED process and injected into a high pressure die casting press. The hot tearing sensitivity results

A. LEMIEUX; J. LANGLAIS; D. BOUCHARD; X. GRANT CHEN

2010-01-01

437

Characterization of Powder Flowability for Die Filling  

Microsoft Academic Search

Inter-tablet variations in composition and weight depend on the flowability of pharmaceutical formulations. In this study, the concept of critical filling speed, which was proposed to characterize the flowability with special application to die filling, is evaluated and compared with other powder flow characterization techniques. It has been found that the critical filling speed provides a consistent gauge of the

Chuan-Yu Wu; Brian Armstrong; Nikolaus Vlachos

2012-01-01

438

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

439

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

440

Biotransformation and ToxCast?  

EPA Science Inventory

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

441

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

442

Friction drilling of cast metals  

Microsoft Academic Search

This study investigates the friction drilling process, a nontraditional hole-making technique, for cast metals. In friction drilling, a rotating conical tool is applied to penetrate work-material and create a bushing in a single step without generating chip. The cast aluminum and magnesium alloys, two materials studied, are brittle compared to the ductile metal workpiece material used in previous friction drilling

Scott F. Miller; Jia Tao; Albert J. Shih

2006-01-01

443

Clogging in Continuous Casting Nozzles  

Microsoft Academic Search

Nozzle clogging is a serious productivity and qua lity problem in continuous casting. This work reviews the causes, effects, and solutions to cloggi ng in continuous casting nozzles. The results of a one-dimensional, steady state analysis of the heat loss from the molten steel stream through the nozzle wall are discussed. The analyses show that steel may freeze within the

K. G. Rackers; B. G. Thomas

444

Stress Corrosion Cracking Behavior of Cast Stainless Steels  

SciTech Connect

Casting of austenitic stainless steels offers the possibility of directly producing large and/or relatively complex structures, such as the first wall shield modules or the diverter cassette for the ITER fusion reactor. Casting offers major cost savings when compared to fabrication via welding of quarter modules machined from large forgings. However, the strength properties of such cast components are typically considered inferior to those of conventionally forged and annealed components. To improve and validate cast stainless steel as a substitute for wrought stainless steel, a development and testing program was initiated, utilizing nitrogen and manganese additions to promote improved performance. This paper focuses on the response of the first set of developmental alloys to neutron-irradiation and susceptibility to stress corrosion cracking. These cast materials may also have applications for different components in light water reactors. Results showed that all steels exhibited irradiation-induced hardening and a corresponding drop in ductility, as expected, although there is still considerable ductility in the irradiated samples. The cast steels all exhibited reduced hardening in comparison to a wrought reference steels, which may be related to a larger grain size. Higher nitrogen contents did not negatively influence irradiation performance. Regarding stress corrosion cracking susceptibility, the large difference in grain size limits the comparison between wrought and cast materials, and inclusions in a reference and archive cast alloy tests complicate analysis of these samples. Results suggest that the irradiated archive heat was more susceptible to cracking than the modified alloys, which may be related to the more complex microstructure. Further, the results suggest that the modified cast steel is at least as SCC resistant as wrought 316LN. The beneficial effect of nitrogen on the mechanical properties of the alloys remains after irradiation and is not detrimental to SCC resistance.

Teysseyre, Sebastien [University of Michigan; Busby, Jeremy T [ORNL; Was, Gary [University of Michigan

2009-01-01

445

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

446

INDUSTRIAL SCALE DIE FILLING AND THE USE OF SHORT SHOTS TO UNDERSTAND THERMAL AND FLOW EFFECTS  

Microsoft Academic Search

The geometric complexity and high fluid speeds involved in High Pressure Die Casting (HPDC) combine to give strongly three dimensional fluid flow with significant free surface fragmentation and splashing. A simulation method that has proved particularly suited to modelling HPDC is Smoothed Particle Hydrodynamics (SPH). Materials are approximated by particles that are free to move around rather than by fixed

Paul W. CLEARY; Joseph HA; Mahesh PRAKASH; Thang NGUYEN

447

Über die Reizwirkung oberflächenaktiver Stoffe auf die Haut  

Microsoft Academic Search

Es wird über tierexperimentelle Untersuchungen berichtet, die mit handelsüblichen Fettalkoholsulfaten, Alkylarylsulfonaten und Fettsäure-Eiweiß-Kondensaten durchgeführt wurden. Im Läppchentest konnte gezeigt werden, daß toxische Reaktionen insbesondere bei höheren Konzentrationen der Fettalkoholsulfate und Alkylarylsulfonate auftraten. Die Fettsäure-Eiweiß-Kondensate übten nur bei hohen Konzentrationen eine geringe Reizwirkung auf die Kaninchenhaut aus.

K. Meinicke

1960-01-01

448

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

449

Die elektrischen Eigenschaften des Bakelits  

Microsoft Academic Search

Zusammenfassung Die Arbeit erstreckt sich auf die Untersuchung der elektrischen Eigenschaften insbesondere des Bakelitproduktes C bei verschiedenen Temperaturen. In einer zweiten Versuchsreihe wird ein Überblick über das elektrische Verhalten der einzelnen Kondensationsprodukte Bakelit A, B und C zu gewinnen versucht.

O. Mannel

1923-01-01

450

Die neuen Deutschs  

Microsoft Academic Search

\\u000a Wir leben im Handy-Zeitalter und kommunizieren über SMS (Short Message Service). Die „thumb generation“ simst, was das Zeug\\u000a hält. Auch Kanzlerin Angela Merkel soll eine Anhängerin des „schnellen Worts“ sein. Auf das Display eines Handys passen keine\\u000a Romane. Deshalb muss man sich kurz halten und Abkürzungen verwenden. Manche sprechen sogar von einem HandyGeheimcode der „Digital\\u000a Natives“. Wenn der Magen knurrt,

Kerstin Liesem; Jörn Kränicke

451

Should assisted dying be lawful?  

PubMed

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

Griffith, Richard

2014-02-01

452

Dehydration and the dying patient  

Microsoft Academic Search

This study investigated the relationship between symptoms and dehydration in 82 subjects with malignant disease. Assessment of respiratory tract secretions, thirst, and dry mouth were made during the dying phase, and serum biochemistry was analyzed. Follow-up data were also collected when the patient died. The median time from entry into the study until death was 2 days. All subjects died

John E. Ellershaw; Jane M. Sutcliffe; Cicely M. Saunders

1995-01-01

453

What Happens When Someone Dies?  

MedlinePLUS

... always be someone in the room with a dying person? Staying close to someone who is dying is often called "keeping a vigil." It can ... alone, is not a sign that someone is dying. But, for someone with a serious illness or ...

454

Manufacturing of Dies and Molds  

Microsoft Academic Search

The design and manufacturing of dies and molds represent a significant link in the entire production chain because nearly all mass produced discrete parts are formed using production processes that employ dies and molds. Thus, the quality, cost and lead times of dies and molds affect the economics of producing a very large number of components, subassemblies and assemblies, especially

Taylan Altan; Blaine Lilly; Y. C. Yen

2001-01-01

455

Squeeze casting of high-strength aluminium wrought alloy AA7010  

Microsoft Academic Search

Historically, the 7000 series alloys were developed for high-strength wrought-form applications and are, therefore, unsuitable for conventionally produced castings. However, in this study it is shown that using the squeeze casting process, porosity-free, fine equiaxed grain components of AA7010 composition can be produced successfully. In the first part of this study, the cast structure of aluminium alloy AA7010 solidified under

T. M. Yue

1997-01-01

456

A mixed-integer linear programming model for the continuous casting planning  

Microsoft Academic Search

The development of optimization models for planning and scheduling is one of the most useful tools for improving productivity of a large number of manufacturing companies. This paper presents a mixed-integer programming model for scheduling steelmaking-continuous casting production. We first review the recent works in continuous casting planning. We focus on a model inspired from an application of steelmaking-continuous casting

A. Bellabdaoui; J. Teghem

2006-01-01

457

Laser-Ultrasonic Inspection of MG/AL Castings  

SciTech Connect

Laser-ultrasonics is used to assess the metallurgical bond between Mg/Al materials in die-cast Magnesium/Aluminum composite. The acoustic impedances of Mg, Al and air are such that the amplitude of ultrasonic echoes reflected back from a void is many times larger than the amplitude of those reflected back from a well-bonded interface. In addition, the polarity of echoes from a void is inverted compared to that from a well-bonded interface. Laser-ultrasonic F-SAFT is also used for imaging tilted Mg/Al interfaces. Experimental setup, signal processing and results for detecting voids in the Mg/Al interface of cast parts are presented.

Blouin, Alain; Levesque, Daniel; Monchalin, Jean-Pierre [Industrial Materials Institute, National Research Council Canada, 75 de Mortagne blvd, Boucherville, Quebec, J4B 6Y4 (Canada); Baril, Eric [Noranda Inc., 2250 Alfred Nobel blvd, St-Laurent, Quebec, H4S 2C9 (Canada); Fischersworring-Bunk, Andreas [BMW Group, Hufelandstr.8a, 80788 Munich (Germany)

2005-04-09

458

Einführung in die Technische Chemie  

NASA Astrophysics Data System (ADS)

Die "Technische Chemie" ist ein Lehrfach an Universitäten und Hochschulen. Nach dem die Studierenden der Chemie in den ersten Semestern ihres Studiums ausrei chen de theoretische Kenntnisse in Allgemeiner, Anorganischer, Organischer und Physikalischer Chemie erlangt haben, soll die Technische Chemie einen Blick auf die praktische Anwendung dieser Naturwissenschaft in unserer Wirtschaft lenken. Es gibt keine "biologische Industrie", "physikalische Industrie" oder "mathematische Industrie", wohl aber seit über 150 Jahren eine "chemische Industrie", die in dieser lan gen Zeit zahlreiche chemische Prozesse entwickelt und dazu vielfältige Methoden erarbeitet hat. Das Lehrfach Technische Chemie gibt einen Überblick über diese Pro zesse und Methoden und erleichtert dadurch den Schritt von der Universität zur be ruflichen Praxis.

Behr, Arno; Agar, David W.; Jörissen, Jakob

459

Cast to Cast Variations in Type 316 Steel.  

National Technical Information Service (NTIS)

The microscopic examination of creep specimens from eight casts of AISI Type 316 stainless steel which ruptured with variable ductility is reported. The specimen microstructures are discussed and attempts are made to identify factors responsible for high ...

A. J. Hooper C. J. Bolton J. Lai J. E. Cordwell P. Marshall

1977-01-01

460

A Quantitative Approach to Casting Solidification: Freezing of Cast Iron.  

National Technical Information Service (NTIS)

The separate processes involved in casting solidification, such as eutectic nucleation and growth, have been previously studied separately in controlled experiments. The interaction of the separate processes has now been treated, using the freezing of cas...

W. Oldfield

1966-01-01

461

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

462

Strip casting with fluxing agent applied to casting roll  

DOEpatents

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

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

1997-07-29

463

Strip casting with fluxing agent applied to casting roll  

DOEpatents

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

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

1997-01-01

464

Control of Cast Grain Size of Steel Castings.  

National Technical Information Service (NTIS)

Techniques for the quantative evaluation of refinement of a high strength cast steel have been evolved and used to test the effectiveness of various inoculants in achieving microstructural and macrostructural refinement. Of the various materials tested on...

P. Wieser N. Church J. F. Wallace

1964-01-01

465

Strip casting apparatus and method  

DOEpatents

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

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

1988-01-01

466

Strip casting apparatus and method  

DOEpatents

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

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

1988-09-20

467

Rapid Manufacturing Via Metal Casting  

NSDL National Science Digital Library

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

Creese, Robert

2009-07-14

468

Biomimetic Materials by Freeze Casting  

NASA Astrophysics Data System (ADS)

Natural materials, such as bone and abalone nacre, exhibit exceptional mechanical properties, a product of their intricate microstructural organization. Freeze casting is a relatively simple, inexpensive, and adaptable materials processing method to form porous ceramic scaffolds with controllable microstructural features. After infiltration of a second polymeric phase, hybrid ceramic-polymer composites can be fabricated that closely resemble the architecture and mechanical performance of natural bone and nacre. Inspired by the narwhal tusk, magnetic fields applied during freeze casting can be used to further control architectural alignment, resulting in freeze-cast materials with enhanced mechanical properties.

Porter, Michael M.; Mckittrick, Joanna; Meyers, Marc A.

2013-06-01

469

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...

470

Quantitative chemical analysis of nickel-chromium dental casting alloys.  

PubMed

Twenty-nine brands of dental casting nickel-chromium alloys made in Japan for small castings were analyzed by electron probe X-ray microanalyzer. Nickel-chromium alloys for metal-ceramic application were composed primarily of nickel, chromium, and molybdenum with the exception of one brand. Of the nickel-chromium alloys for inlay, crown, and bridgework applications, 11 of the 22 alloys were up to the standard of the Ministry of Welfare specifications. And additive metal elements of these alloys were molybdenum, iron, copper, manganese, aluminum, silicon, tin, indium, silver, titanium, and gallium. PMID:2134288

Nagayama, K; Kuroiwa, A; Ando, Y; Hashimoto, H

1990-01-01

471

Investment casting design of experiment. Final report  

SciTech Connect

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

Owens, R.

1997-10-01

472

Machine Casting of Ferrous Alloys.  

National Technical Information Service (NTIS)

Emphasis of the work at the University of Illinois is on processes and casting systems which employ a partially solid alloy as charge material. The program at the University of Illinois is especially designed to establish the processing conditions necessa...

R. Mehrabian D. G. Backman G. J. Abbaschian Y. V. Murty S. D. E. Ramati

1977-01-01

473

A New 'Shell Casting' Technic.  

National Technical Information Service (NTIS)

A new shell investment was formulated that hardened rapidly enough so that consecutive layers could be applied to a wax pattern without requiring intermediate drying cycles between each layer. This new 'shell casting investment' is a two component system....

E. R. Dootz R. G. Craig F. A. Peyton

1966-01-01

474

Care of Casts and Splints  

MedlinePLUS

... support. Casts can be made of plaster or fiberglass — a plastic that can be shaped. Splints or ... to put on, take off, and adjust. Materials Fiberglass or plaster materials form the hard supportive layer ...

475

Casting Using A Polystyrene Pattern  

NASA Technical Reports Server (NTRS)

New technique for making metal aircraft models saves significant amount of time and effort in comparison with conventional lost-wax method. Produces inexpensive, effective wind-tunnel models. Metal wind-tunnel model cast by use of polystyrene pattern.

Vasquez, Peter; Guenther, Bengamin; Vranas, Thomas; Veneris, Peter; Joyner, Michael

1993-01-01

476

Nitriding of Aluminum Extrusion Die: Effect of Die Geometry  

NASA Astrophysics Data System (ADS)

Nitriding of complex-shaped extrusion dies may result in non-uniform nitride layers and hence a required hardness may not be achieved in some regions of the bearing area. The present study is carried out to assess the effect of extrusion die profile on the characteristics and growth behavior of nitride layers so that the critical die design feature can be identified to enhance the uniformity of the nitride layer. For this purpose, AISI H13 steel samples have been manufactured with profiles similar to those of hot extrusion dies. The samples were then gas nitrided under controlled nitriding potential. The uniformity and depth of nitride layers have been investigated in terms of compound layer and total nitride case depth for selected die features. The results of this study indicated the need to include the effect of profile on the nitride layer for the optimal die design with improved service life.

Akhtar, S. S.; Arif, A. F. M.; Yilbas, B. S.

2010-04-01

477

Investment casting of gold jewellery  

Microsoft Academic Search

Porosity is one of the important causes for the rejection of jewellery items cast by the lost wax process. If it is of the\\u000a shrinkage type, then there is a considerable reservoir of knowledge, arising from experience in the casting of dental gold\\u000a and other gold alloys, which can be drawn upon to overcome the problem. If it is gas

Dieter Ott; Christoph J. Raub; William S. Rapson

1985-01-01

478

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

SciTech Connect

White cast irons are frequently used in applications requiring high wear resistance. High Cr white cast irons have a composite microstructure comp