Sample records for die casting impact

  1. Enhancements in Magnesium Die Casting Impact Properties

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


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

  2. Impact properties of zinc die cast alloys

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


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

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

    Neto, B.; Kroeze, C.; Hordijk, L.; Costa, C.; Pulles, M.P.J.


    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,

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

    Neto, B.; Kroeze, C.; Hordijk, L.; Costa, C.; Pulles, M.P.J.


    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,

  5. Materials on dies for pressure die casting

    E. Ragan


    Full Text Available In the contribution the stress of die materials of thermal fatigue is defi ned and material life is derived theoretically and compared with the measured values. The important properties of the die materials as thermal conductivity, coeffi cient of thermal expansivity, modulus of elasticity and mechanical properties are described. Binding to it single die materials as carbon steels and chrome-tungsten steels are analyzed. As the perspective die material for pressure die casting of ferrous metals appears molybdenum with regard to advantageous properties.

  6. Die Soldering in Aluminium Die Casting

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


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

  7. Structure of Water Mist Stream and its Impact on Cooling Efficiency of Casting Die

    R. Władysiak


    Full Text Available The work is a continuation of research on the use water mist cooling in order to increase efficiency of die-casting aluminum alloys. The paper presents results of research and analysis process, spraying water and generated a stream of water mist, the effect of the type of nozzle, the nozzle size and shape of the emitting of the water mist on the wall surface of casting die on the microstructure and geometry of water mist stream and cooling efficiency. Tests were used to perform high-speed camera to record video in the visible and infrared camera. Results were used to develop a computerized image analysis and statistical analysis. The study showed that there are statistical relationships between water and air flow and geometry of the nozzle and nozzle emitting a stream of microstructure parameters of water mist and heat the incoming stream. These relationships are described mathematical models that allow you to control the generating of adequate stream of water mist and a further consequence, the cooling efficiency of casting die.

  8. Casting Characteristics of Aluminum Die Casting Alloys

    Makhlouf M. Makhlouf; Diran Apelian


    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.

  9. Development of vacuum die-casting process

    Masashi Uchida


    The vacuum die-casting process, started 25 years ago in Japan, has been widely applied. This technology contributes very much to improvement of castings quality. The main factor causing the defects of die castings is the trapped air in the mold cavity, while the key technology of vacuum die-casting process is to avoid the trapped air effectively by evacuating the cavity before casting. At the same time, due to the shot speed and the casting pressure reduced in half, the service life of the die is prolonged and the productivity is enhanced, as well. Vacuum die-casting process is of great significance in improving the die castings quality and making up the shortcomings of super-high-speed shot casting.

  10. Simulating a high pressure die casting

    Goldak, J.; Zhou, J.; Downey, D.; Aldea, V.; Li, G.; Mocanita, M. [Carleton Univ., Ottawa, Ontario (Canada)


    High pressure die casting is simulated for parts with complex geometry such as a large automotive transmission case. The closed die is filled in approximately 40 ms, the casting cools in the closed die for approximately 40s, to open the die, eject the casting and spray the die cavity surface requires another 40s. This 3D cyclic process is simulated using the following coupled composite solvers: the energy equation in the die and in the casting with solidification; filling of the casting by a droplet or a Navier-Stokes solver, and thermal stress analysis of the casting machine, casting and die during the cycle. This thermal analysis can be done for both starting and stopping transients and for the cyclic steady state. The software enables this analysis to be done almost automatically by designers. (author)

  11. Energy Consumption of Die Casting Operations

    Jerald Brevick; clark Mount-Campbell; Carroll Mobley


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

  12. Prediction of Part Distortion in Die Casting

    R. Allen Miller


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

  13. Homogenity of Die Casting and Returning Material

    J. Malik


    Full Text Available Homogeneity of die castings is influenced by wide range of technological parameters as piston velocity in filling chamber of die casting machine, filling time of mould cavity, temperature of cast alloy, temperature of the mould, temperature of filling chamber, surface pressure on alloy during mould filling, final pressure and others. Based on stated parameters it is clear, that main parameters of die casting are filling time of die mould cavity and velocity of the melt in the ingates. Filling time must ensure the complete filling of the mould cavity before solidification process can negatively influence it. Among technological parameters also belong the returning material, which ratio in charge must be constrained according to requirement on final homogeneity of die castings. With the ratio of returning material influenced are the mechanical properties of castings, inner homogeneity and chemical composition.

  14. Improvement of die life in high speed injection die casting

    Yasuhiro Arisuda; Akihito Hasuno; Junji Yoshida; Kazunari Tanii


    High-speed injection die casting is an efficient manufacturing technology for upgrading aluminum die-cast products. However, deficiencies (such as die damage in eady period) due to larger load on the molding die compared with conventional technology have brought new challenges. In this study, the cause of damage generated in super high-speed injection was investigated by the combination of experimental observation of the dies and CAE simulation (e.g. die temperature analysis, flow analysis and thermal stress analysis). The potential countermeasures to solve the above problems were also proposed.

  15. Improvement of die life in high speed injection die casting

    Akihito Hasuno


    Full Text Available High-speed injection die casting is an effi cient manufacturing technology for upgrading aluminum die-cast products. However, defi ciencies (such as die damage in early period due to larger load on the molding die compared with conventional technology have brought new challenges. In this study, the cause of damage generated in super high-speed injection was investigated by the combination of experimental observation of the dies and CAE simulation (e.g. die emperature analysis, fl ow analysis and thermal stress analysis. The potential countermeasures to solve the above problems were also proposed.

  16. An Integrated Die Casting Design System

    Y; K; Woon; K; S; Lee


    Die casting process is one of the prime options for m anufacturing precisely dimensioned, sharply defined metal parts. The design of d ie casting dies comprises several stages and entails a large amount of time. Tra ditionally, the different stages of the die design were not integrated but exist as separate entities. Moreover, recurring modifications or even redesigns are r equired due to the complexity in achieving an accurate initial die design. As a result, die design is usually time-consuming and cos...

  17. Modeling the Mechanical Performance of Die Casting Dies

    R. Allen Miller


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

  18. Microstructures and properties of aluminum die casting alloys

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


    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.

  19. Cradle-to-Gate Impact Assessment of a High-Pressure Die-Casting Safety-Relevant Automotive Component

    Cecchel, Silvia; Cornacchia, Giovanna; Panvini, Andrea


    The mass of automotive components has a direct influence on several aspects of vehicle performance, including both fuel consumption and tailpipe emissions, but the real environmental benefit has to be evaluated considering the entire life of the products with a proper life cycle assessment. In this context, the present paper analyzes the environmental burden connected to the production of a safety-relevant aluminum high-pressure die-casting component for commercial vehicles (a suspension cross-beam) considering all the phases connected to its manufacture. The focus on aluminum high-pressure die casting reflects the current trend of the industry and its high energy consumption. This work shows a new method that deeply analyzes every single step of the component's production through the implementation of a wide database of primary data collected thanks to collaborations of some automotive supplier companies. This energy analysis shows significant environmental benefits of aluminum recycling.

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

    Shivpuri, R.


    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.

  1. Opportunities and challenges of Chinese die-casting market


    The present status and perspectives of Chinese die-casting market were commented. In 2003, the total output of die castings in the whole country was 708 000 tons, in which the outputs of Al-alloy, Zn-alloy, Mg-alloy, Cu-alloy die castings were 474 600 tons, 222 000 tons, 5 800 tons, 5 600 tons, respectively, each accounted for 67%, 31.35%, 0.85%,0.8% of the total. The annual sale volume of die-casting machines was approximately 1 800. And the gross output value of dies approached RMB 38 billion, in which die-casting dies accounted for about 10%. In the die-casting industry of the entire country, the foreign capital enterprises, public-run enterprises, township and village enterprises, private enterprises accounted for over 80% of the total die-casting enterprises. Super huge die-casting groups are forming.

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

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


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

  3. Die casting process otimization using Taguchi method

    Denilson Jose Viana


    Full Text Available The aluminum die casting process has developed significantly in recent decades, occupying a prominent place for producing innovative engineering components. Among quality problems of this process is porosity due to several factors, including the process parameters that are difficult to determine, and are commonly selected by trial and error approach. This paper sought to answer the question: How to determine the best set of parameters of the aluminum die casting process to minimize porosity in the parts produced? Aiming to improve die casting aluminum parts quality through reducing of porosity. The main contribution of this paper focuses on the application of Taguchi method using ordinal categorical data (porosity classes as a quality characteristic, by analyzing the weighted signal-to-noise ratio. The experimental results were analyzed from the average effect of factors and analysis of variance (ANOVA.  In conclusion parameters metal temperature and speed of the first and second injection phase were the most significant in reducing the porosity of the part studied. Also, the Taguchi method achieved the expected result, bringing significant reduction of porosity in the part studied by optimizing the process parameters.

  4. Thermal Fatigue of Die-Casting Dies: An Overview

    Abdulhadi Hassan A.


    Full Text Available Coupled studies by experimental and numerical simulations are necessary for an increased understanding of the material behaviour as related to the interaction between the thermal and mechanical conditions. This paper focus on the mechanisms of thermal fatigue in the failure of dies and cores used in the die casting of aluminum alloys. The thermal fatigue resistance is expressed by two crack parameters which are the average maximum crack and the average cracked area. Samples of various types of H13 steel were compared with a standard H13 steel by testing under identical thermal fatigue cycles. To determine the thermal constraint developed in the sample during the test, a finite difference technique was used to obtain the temperature distribution, based on temperature measurements at the boundaries. The resulting stresses and strains were computed, and the strain calculated at the edge or weakest point of the sample was used to correlate the number of cycles to crack initiation. As the strain at the edge increased, the number of cycles to failure decreased. The influence of various factors on thermal fatigue behavior was studied including austenitizing temperature, surface condition, stress relieving, casting, vacuum melting, and resulfurization. The thermal fatigue resistance improved as the austenitizing temperature increased from 1750 to 2050ºF.

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

    Domkin, Konstantin; Hattel, Jesper Henri; Thorborg, Jesper


    Soldering of cast alloys to the dies has been a continuing source of die surface damage in the aluminum die-casting industry. To reduce the repair and maintenance costs, an approach to modeling the damage and predicting the die lifetime is required. The aim of the present study is the estimation...... of the die lifetime based on a quantitative analysis of die soldering in the framework of the numerical simulations of the die-casting process. Full 3D simulations of the process, including the filling. solidification, and the die cooling, are carried out using the casting simulation software MAGMAsoft....... The resulting transient temperature fields on the die surface and in the casting are then post-processed to estimate the die soldering. The present work deals only with the metallurgical/chemical kind of soldering which occurs at high temperatures and involves formation and growth of intermetallic layers...

  6. Technological parameters of die casting and quality of casting from EN AC46500 alloy


    Die casting represents the highest technological level of metal mold casting. This technology enables production of almost all final products without necessity of further processing. The important aspect of efficiency and production is a proper casting parameters setting. In the submitted paper following die casting parameters are analyzed: plunger pressing speed and pressure. The studied parameters most significantly affect a qualitative of castings from EN AC46500 alloy and they influence t...

  7. Evaluation of porosity in Al alloy die castings

    M. Říhová


    Full Text Available Mechanical properties of an Al-alloy die casting depend significantly on its structural properties. Porosity in Al-alloy castings is one of the most frequent causes of waste castings. Gas pores are responsible for impaired mechanical-technological properties of cast materials. On the basis of a complex evaluation of experiments conducted on AlSi9Cu3 alloy samples taken from the upper engine block which was die- cast with and without local squeeze casting it can be said that castings manufactured without squeeze casting exhibit maximum porosity in the longitudinal section. The area without local squeeze casting exhibits a certain reduction in mechanical properties and porosity increased to as much as 5%. However, this still meets the norms set by SKODA AUTO a.s.

  8. Effect of Some Parameters on the Cast Component Properties in Hot Chamber Die Casting

    Singh, Rupinder; Singh, Harvir


    Hot chamber die casting process is designed to achieve high dimensional accuracy for small products by forcing molten metal under high pressure into reusable moulds, called dies. The present research work is aimed at study of some parameters (as a case study of spring adjuster) on cast component properties in hot chamber die casting process. Three controllable factors of the hot chamber die casting process (namely: pressure at second phase, metal pouring temperature and die opening time) were studied at three levels each by Taguchi's parametric approach and single-response optimization was conducted to identify the main factors controlling surface hardness, dimensional accuracy and weight of the casting. Castings were produced using aluminium alloy, at recommended parameters through hot chamber die casting process. Analysis shows that in hot chamber die casting process the percentage contribution of second phase pressure, die opening time, metal pouring temperature for surface hardness is 82.48, 9.24 and 6.78 % respectively. While in the case of weight of cast component the contribution of second phase pressure is 94.03 %, followed by metal pouring temperature and die opening time (4.58 and 0.35 % respectively). Further for dimensional accuracy contribution of die opening time is 76.97 %, metal pouring temperature is 20.05 % and second phase pressure is 1.56 %. Confirmation experiments were conducted at an optimal condition showed that the surface hardness, dimensional accuracy and weight of the castings were improved significantly.

  9. New trends in cold-chamber die casting machine design

    R. Dańko


    Full Text Available Larger and larger proportions of aluminium castings, especially those produced by the die casting process, can be observed during recent years in the automotive industry, house-hold articles and others. In case of the automotive industry, apart from the traditional elements produced by the die pressure method such as engine blocks or crank shaft bedplates, aluminium is displacing steel from structural parts of cars (‘body in white’. The current state and development directions of the structural solutions of cold-chamber die castings are analysed in this paper. These solutions drive the prospective development of these machines and die casting technology. The focus is mainly on essential functional systems such as: hydraulic drives of closing and locking units, as well as pressing in die machines of known companies present on the European market.

  10. New trends in cold-chamber die casting machine design

    R. Dańko; W. Kowalczyk


    Larger and larger proportions of aluminium castings, especial y those produced by the die casting process, can be observed during recent years in the automotive industry, house-hold articles and others. In case of the automotive industry, apart from the traditional elements produced by the die pressure method such as engine blocks or crank shaft bedplates, aluminium is displacing steel from structural parts of cars (‘body in white’). The current state and development directions of the structural solutions of cold-chamber die castings are analysed in this paper. These solutions drive the prospective development of these machines and die casting technology. The focus is mainly on essential functional systems such as:hydraulic drives of closing and locking units, as wel as pressing in die machines of known companies present on the European market.

  11. Thermo-mechanical cracking of a new and laser repair welded die casting die

    D. Klobčar


    Full Text Available The paper presents the analysis of thermo-mechanical fatigue cracking of die casting die during industrial use. An innovative, production friendly approach to monitor the surface crack dimensions was introduced, which is based on measuring defect-fin on the casting part. A new four moulds die casting die was monitored 40 000 cycles in order to complete the production series. The production was stopped three times for laser repair welding of cracks since the defect-fins were not acceptable. The defect-fin heights were measured every 1 000 cycles on the castings before and after repair welding of die surface cracks. The in-service die life can be prolonged with laser repair welding for several times, even thought that in-service die life for a particular repair varies.

  12. Technological parameters of die casting and quality of casting from EN AC46500 alloy

    Š. Gašpár


    Full Text Available Die casting represents the highest technological level of metal mold casting. This technology enables production of almost all final products without necessity of further processing. The important aspect of efficiency and production is a proper casting parameters setting. In the submitted paper following die casting parameters are analyzed: plunger pressing speed and pressure. The studied parameters most significantly affect a qualitative of castings from EN AC46500 alloy and they influence the most a gained porosity level as well as basic mechanical properties represented by permanent deformations.

  13. Successful Asia-Pacific Die Casting Industry Exhibition'2005


    @@ Upon the expectation of practitioners in the die casting industry, the Asia-Pacific Die Casting Industry Exhibition'2005, sponsored by Chinese Mechanical Engineering Society (CMES) and China Productivity Promotion Center of Machinery Industry, organized by Foundry Institution of Chinese Mechanical Engineering Society (FICMES) and Productivity Promotion Center of Foundry Industry of China, was successfully held in INTEX Shanghai, China on August 13-17,2005.

  14. Die design and process optimization of die cast V6 engine blocks


    The use of aluminum, particularly for engine blocks, has grown considerably in the past ten years, and continues to rise in the automotive industry. In order to enhance the quality and engineering functionality of die cast engine blocks, die design and processes have to be optimized. In this study, a computer simulation software,MAGMAsoft, as an advanced tool for optimizing die design and casting process, was employed to virtually visualize cavity filling and patterns of a V6 engine block. The original die design and process was simulated first to establish a baseline.A reality check was used to verifythe predicted results. Then, the die modification with a different runner system was made by using a CAD software, Unigraphics (UG). The simulation on combinations of the modified die design and revised process was performed to examine the effect of die modification and process change on flow filling of V6 engine blocks. The simulated prediction indicates that the enhancement of cavity filling due to the die and process modification minimizes the occurrence of defects during casting, and consequently improves the quality of blocks. The results of mechanical testing show a significant increase in fatigue strengths, and a moderately improvement on tensile properties for the blocks die cast with the new die design and process in comparison with those produced by the original ones.

  15. Strength Estimation of Die Cast Beams Considering Equivalent Porous Defects

    Park, Moon Shik [Hannam Univ., Daejeon (Korea, Republic of)


    As a shop practice, a strength estimation method for die cast parts is suggested, in which various defects such as pores can be allowed. The equivalent porosity is evaluated by combining the stiffness data from a simple elastic test at the part level during the shop practice and the theoretical stiffness data, which are defect free. A porosity equation is derived from Eshelby's inclusion theory. Then, using the Mori-Tanaka method, the porosity value is used to draw a stress-strain curve for the porous material. In this paper, the Hollomon equation is used to capture the strain hardening effect. This stress-strain curve can be used to estimate the strength of a die cast part with porous defects. An elastoplastic theoretical solution is derived for the three-point bending of a die cast beam by using the plastic hinge method as a reference solution for a part with porous defects.

  16. Die Casting Mold Design for Aluminum Alloy Shell of Instrument

    Li Yuanyuan


    Full Text Available This paper is about die casting mold design for aluminum alloy shell of instrument. Three-dimensional model of the casting and mold are designed by using Pro/Engineer and AutoCad which can analyze forming quality. Digital design and theoretical calculation can greatly shorten product development cycle and mold design cycle, improve the accuracy of product design and mold design, and reduce the cost of mold design.

  17. Die casting process assessment using single minute exchange of dies (SMED method

    M. Perinić


    Full Text Available Die casting process uses high productive level machines. Machine capacity utilization is a key goal in achieving minimum time consumption. Changeover procedure during die casting process is recognized as possible area for reducing time consumption. The SMED method has been improved by additional procedures simultaneously applying the 5S method. Their contribution is evident in recognition of internal and external activities, particularly while transferring internal activities into external ones in as many numbers as possible, by minimizing at the same moment the internal ones. The validity of the method and procedures are verified by an example application of die casting foundry for casting automobile parts. Significant time savings have been achieved with minimum investment.

  18. Optimization of die filling in high pressure die cast part using MAGMAsoft®

    Kotas, Petr; Hattel, Jesper Henri


    using the commercial software code MAGMAsoft®. The first process analysis revealed problems and defects of the casting which were cold shuts and out-of plane distortions. Secondly adjustment in the geometry of the casting and the gating system were carried out and evaluated. Last, modifications...... in the process and machine parameters were done and assessed. All simulations revealed that, the main causes of the problems were: a poor geometry of the casting leading to an improper filling pattern, and a massive gating system bringing thermal imbalance into the solidification process. Thus deformations due......Integrated modeling of an entire casting process has become a tool which favors design and optimization of manufactured parts. The aim of this project was to examine and optimize a high-pressure die cast part and its production process with respect to die filling and issues of residual stresses...

  19. Effect of mold designs on molten metal behaviour in high-pressure die casting

    Ibrahim, M. D.; Rahman, M. R. A.; Khan, A. A.; Mohamad, M. R.; Suffian, M. S. Z. M.; Yunos, Y. S.; Wong, L. K.; Mohtar, M. Z.


    This paper presents a research study conducted in a local automotive component manufacturer that produces aluminium alloy steering housing local and global markets. This study is to investigate the effect of design modification of mold in die casting as to improve the production rate. Design modification is carried out on the casting shot of the mold. Computer flow simulation was carried out to study the flow of molten metal in the mold with respect to the mold design modification. The design parameters of injection speed, die temperature and clamping force has been included in the study. The result of the simulation showed that modifications of casting shot give significant impact towards the molten flow behaviour in casting process. The capabilities and limitations of die casting process simulation to conduct defect analysis had been optimized. This research will enhance the efficiency of the mass production of the industry of die casting with the understanding of defect analysis, which lies on the modification of the mold design, a way early in its stages of production.

  20. Study on the microstructure and mechanical properties of medium carbon Cr-Si-Mn-Mo-V steel for cast inserted dies

    HAO Xiao-yan


    Full Text Available The microstructure and mechanical properties of cast inserted dies for automobile covering components were studied. The results show that the as-cast microstructures of cast inserted dies are composed of pearlite, martensite,bainite, and austenite; and that the annealed microstructure is granular pearlite. The mechanical properties of cast inserted dies approach that of forged inserted dies. The tensile strength is 855 MPa, the elongation is 16%, the impact toughness is 177 J/cm2, and the hardness after annealing and quenching are HRC 19 and HRC 60-62. In addition, the cast inserted dies have good hardenability. The depth of the hardening zone and the hardness after flame quenching satisfy the operating requirements. The cast inserted dies could completely replace the forged inserted dies for making the dies of automobile covering components.

  1. Processing Technology and Mechanical Properties of Die-Cast Magnesium Alloy AZ91D

    LIU Yan'gai(刘艳改); LIU Wenhui(刘文辉); XIONG Shoumei(熊守美); LIU Baicheng(柳百成); Wang Gang (王罡); MATSUMOTO Yoshihide; MURAKAMI Masayuki


    The mechanical properties of magnesium die-casting components can be improved with improved die-casting processing technology. An orthogonal experiment with four factors and three levels (Lq, 34) was used to evaluate the effect of various die-casting processing parameters on the quality and mechanical properties of an AZ91D magnesium alloy cylinder head cover component. The results show that the injection speed and casting and die temperatures all influence the component quality, with the influence of the casting pressure being the smallest. The injection speed and casting pressure are the two most important factors influencing the tensile strength. The best die-casting parameters for the magnesium alloy cylinder head cover component were determined to be a casting temperature of 660℃, a die temperature of 200℃, an injection speed of 70 ms(1, and a casting pressure of 65 MPa. The porosity is one of the most important parameters influencing the casting strength.

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

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


    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.

  3. Numerical simulation of low pressure die-casting aluminum wheel

    Mi Guofa; Liu Xiangyu; Wang Kuangfei; Fu Hengzhi


    The FDM numerical simulation software, ViewCast system, was employed to simulate the low pressure die casting (LPDC) of an aluminum wheel. By analyzing the mold-filling and solidification stage of the LPDC process, the distribution of liquid fraction, temperature field and solidification pattern of castings were studied. The potential shrinkage defects were predicted to be formed at the rim/spoke junctions, which is in consistence with the X-ray detection result. The distribution pattern of the defects has also been studied. A solution towards reducing such defects has been presented. The cooling capacity of the mold was improved by installing water pipes both in the side mold and the top mold. Analysis on the shrinkage defects under forced cooling mode proved that adding the cooling system in the mold is an effective method for reduction of shrinkage defects.

  4. An optimization of injecting system in die casting


    After many years of development, die casting technology of metallic materials has been matured. In this paper,the lower-support and its injecting system were created with commercial software. And then the simulation software FLOW3D was applied to study the flow behavior of the melt during injection filling process. Both temperature field and defect distribution were simulated. Based on these results, the better injecting system with two additional overflows was adopted.

  5. Energy and resource efficiency in aluminium die casting

    Heinemann, Tim


    This monograph provides a field-proven approach to analyze industrial production with a cross-company scope as well as regarding all hierarchical system levels of manufacturing enterprises. The book exemplifies this approach in the context of aluminum  die casting, and presents a set of measures which allow a 30 percent energy reduction along the value chain. The target audience primarily comprises researchers and experts in the field but the book may also be beneficial for graduate students.

  6. An optimization of injecting system in die casting

    Wei WU


    Full Text Available After many years of development, die casting technology of metallic materials has been matured. In this paper,the lower-support and its injecting system were created with commercial software. And then the simulation software FLOW3D was applied to study the flow behavior of the melt during injection filling process. Both temperature field and defect distribution were simulated. Based on these results, the better injecting system with two additional overflows wasadopted.

  7. Mechanisms of fatigue-crack initiation and their impact on fatigue life of AlSi7 die-cast components

    Redik Sabine


    Full Text Available In the course of the present study, in-situ observations of crack initiation and crack growth of naturally induced cracks in cyclically loaded specimens along with conventional fatigue tests and fracture surface analyses were performed. The specimens used were taken from different sampling positions of standard and HIPed aluminum-die-cast engine blocks, with different cooling conditions. In one sampling position within the standard engine block microporosity was able to form, acting as a source for fatigue-crack initiation. While in the absence of microporosity, as observed in specimens taken from HIPed components, crack initiation occured via slip band mechanism. If material defects such as pores were present, premature crack initiation reduced the fatigue life yielding a lower fatigue life and fatigue strength than specimens where cracks formed by slip band mechanism. For cracks formed at pores, the pore size is the determining factor for fatigue behavior. While for cracks initiated via slip band mechanism fatigue strength is a function of the local material strength.


    M.F.V.T. Pereira


    Full Text Available

    ENGLISH ABSTRACT: A number of laser additive manufacturing (LAM technologies can produce fully-dense metal components that potentially offer opportunities to apply the technology in die or mould making (known as rapid tooling. From these LAM technologies, three were selected for evaluation of their suitability as die cavity inserts in the manufacture of high pressure die-casting (HPDC dies. Apart from comparing the different LAM inserts with one another, their performance was also compared with components manufactured in a standard hot work steel. In the HPDC process, the die is unique to each component to be produced. Die cavities in particular are subjected to demanding conditions, such as cyclic heating caused by the introduction of molten aluminium at over 650°C, followed by cooling in water-based die release medium at temperatures around 25°C. Besides cyclic heating, the die cavities are also exposed to pressures exceeding 1500 MPa during the injection of molten aluminium into the cavities. This application of LAM, therefore, poses extreme challenges to the technology. The results of this study confirmed that the metals used in some of the LAM technologies did indeed meet the demanding requirements of the current application, and can lead to significant time- and cost-saving during product or process developments. Based on these findings, a number of recommendations are made for users interested in the application of LAM to produce die cavities.

    AFRIKAANSE OPSOMMING: ’n Aantal laser laagvervaardigingstegnologieë (LLV tegnolgieë is in staat om volledig digte metaalkomponente te lewer, wat tot gevolg het dat hierdie tegnologie potensieel vir vormingsmatrys- of gietmatrysvervaardiging gebruik kan word (bekend as snelgereedskap. Drie van hierdie LLV tegnologieë is gekies vir evaluasie van hulle geskiktheid as gietvorminsetsels tydens die vervaardiging van gietmatryse vir hoë druk matrysgiet (HDMG. Benewens die onderlinge

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

    Cao, Yongyou; Guo, Zhipeng; Xiong, Shoumei


    High-pressure die cast B390 alloy was prepared on a 350 ton cold chamber die casting machine. The metal/die interfacial heat transfer coefficient of the alloy was investigated. Considering the filling process, a "finger"-shaped casting was designed for the experiments. This casting consisted of five plates with different thicknesses (0.05 inch or 1.27 mm to 0.25 inch or 6.35 mm) as well as individual ingates and overflows. Experiments under various operation conditions were conducted, and temperatures were measured at various specific locations inside the die. Based on the results, the interfacial heat transfer coefficient and heat flux were determined by solving the inverse heat transfer problem. The influence of the mold-filling sequence, sensor locations, as well as processing parameters including the casting pressure, die temperature, and fast/slow shot speeds on the heat transfer coefficient were discussed.

  10. High pressure die casting of Fe-based metallic glass

    Ramasamy, Parthiban; Szabo, Attila; Borzel, Stefan; Eckert, Jürgen; Stoica, Mihai; Bárdos, András


    Soft ferromagnetic Fe-based bulk metallic glass key-shaped specimens with a maximum and minimum width of 25.4 and 5 mm, respectively, were successfully produced using a high pressure die casting (HPDC) method, The influence of die material, alloy temperature and flow rate on the microstructure, thermal stability and soft ferromagnetic properties has been studied. The results suggest that a steel die in which the molten metal flows at low rate and high temperature can be used to produce completely glassy samples. This can be attributed to the laminar filling of the mold and to a lower heat transfer coefficient, which avoids the skin effect in the steel mold. In addition, magnetic measurements reveal that the amorphous structure of the material is maintained throughout the key-shaped samples. Although it is difficult to control the flow and cooling rate of the molten metal in the corners of the key due to different cross sections, this can be overcome by proper tool geometry. The present results confirm that HPDC is a suitable method for the casting of Fe-based bulk glassy alloys even with complex geometries for a broad range of applications.

  11. The effect of equipment efficiency on occurrence of non-conforming products in die casting

    S. Borkowski


    Full Text Available This study focuses on determination of the relationships between equipment efficiency in casting machines and the level of quality. The determination was made based on coefficients of Total Productive Maintenance and r correlation coefficient. The degree at which break-downs and downtime affect the occurrence of non-conforming products was also evaluated. The goal of further investigations is to deter-mine the structure of downtime and finding which downtime types have greatest impact on the quality of die-casting products.

  12. Development of Thin Section Zinc Die Casting Technology

    Goodwin, Frank [International Lead Zinc Research Org., Inc., Durham, NC (United States)


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

  13. Aluminium Foam and Magnesium Compound Casting Produced by High-Pressure Die Casting

    Iban Vicario


    Full Text Available Nowadays, fuel consumption and carbon dioxide emissions are two of the main focal points in vehicle design, promoting the reduction in the weight of vehicles by using lighter materials. The aim of the work is to evaluate the influence of different aluminium foams and injection parameters in order to obtain compound castings with a compromise between the obtained properties and weight by high-pressure die cast (HPDC using aluminium foams as cores into a magnesium cast part. To evaluate the influence of the different aluminium foams and injection parameters on the final casting products quality, the type and density of the aluminium foam, metal temperature, plunger speed, and multiplication pressure have been varied within a range of suitable values. The obtained compound HPDC castings have been studied by performing visual and RX inspections, obtaining sound composite castings with aluminium foam cores. The presence of an external continuous layer on the foam surface and the correct placement of the foam to support injection conditions permit obtaining good quality parts. A HPDC processed magnesium-aluminium foam composite has been developed for a bicycle application obtaining a suitable combination of mechanical properties and, especially, a reduced weight in the demonstration part.

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

    Carroll Mobley; Yogeshwar Sahai; Jerry Brevick


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

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

    Miller, R.Allen; Ahuett-Garza, Horacio; Choudhury, Aswin K.; Dedhia, Sanjay


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

  16. Modelling the Cast Component Weight in Hot Chamber Die Casting using Combined Taguchi and Buckingham's π Approach

    Singh, Rupinder


    Hot chamber (HC) die casting process is one of the most widely used commercial processes for the casting of low temperature metals and alloys. This process gives near-net shape product with high dimensional accuracy. However in actual field environment the best settings of input parameters is often conflicting as the shape and size of the casting changes and one have to trade off among various output parameters like hardness, dimensional accuracy, casting defects, microstructure etc. So for online inspection of the cast components properties (without affecting the production line) the weight measurement has been established as one of the cost effective method (as the difference in weight of sound and unsound casting reflects the possible casting defects) in field environment. In the present work at first stage the effect of three input process parameters (namely: pressure at 2nd phase in HC die casting; metal pouring temperature and die opening time) has been studied for optimizing the cast component weight `W' as output parameter in form of macro model based upon Taguchi L9 OA. After this Buckingham's π approach has been applied on Taguchi based macro model for the development of micro model. This study highlights the Taguchi-Buckingham based combined approach as a case study (for conversion of macro model into micro model) by identification of optimum levels of input parameters (based on Taguchi approach) and development of mathematical model (based on Buckingham's π approach). Finally developed mathematical model can be used for predicting W in HC die casting process with more flexibility. The results of study highlights second degree polynomial equation for predicting cast component weight in HC die casting and suggest that pressure at 2nd stage is one of the most contributing factors for controlling the casting defect/weight of casting.

  17. Influences of Casting Pressure Conditions on the Quality and Properties of a Magnesium Cylinder Head Cover Die Casting

    Wenhui LIU; Yangai LIU; Shoumei XIONG; Baicheng LIU; Y. Matsumoto; M. Murakami


    Casting pressure conditions have great influences on the casting defects, such as gas porosity, shrinkage porosity and gas holes. A Mg cylinder head cover die casting was used to experimentally study the influences of casting pressure,the loading time and the piston position of pressure intensification on the variation of pressure and the quality of casting. The results show that casting pressure, the loading time and the piston position of pressure intensification have great influences on the pressure variations in the mold, the quality and performance of casting. The external quality, the density and the tensile strength of casting were improved with the increase of casting pressure and the piston position of pressure intensification and the decrease of the loading time of pressure intensification.

  18. Reducing non value adding aluminium alloy in production of parts through high pressure die casting

    Pereira, MFVT


    Full Text Available The difficulties and issues associated with the economics of the process and die life in casting Aluminium alloys, as experienced by the high pressure die casting industry, were reasons behind undertaking this research project. The use of a tungsten...

  19. Tool Steels in Die-Casting Utilization and Increased Mold Life

    Sepanta Naimi


    Full Text Available In die-casting molds, heat-checking is the typical failure mechanism. Optimizing the parameters that decrease this failure venture should be considered when designing and heat treating steels. The quality of die steels and their treatment continue to improve. This research investigated properties of the traditional materials 1.2343 and 1.2344 and the new steels (Dievar and TOOLOX 44 when applied to the die-casting mold specimens, after different experimental cycles. Also microstructures of the mentioned materials were analyzed by scanning electron microscopy (SEM test. Chrome-molybdenum-silicon-vanadium steels have good hardening ability in oil and in air. Therefore, the hot-work steels have considerable toughness and plastic attributes through both regular and higher temperatures. So, it is a good traditional die-casting material. However, another special die steel, such as Dievar, is a particularly developed steel grade; its exclusivity profile is exceptional due to its chemical composition and the use of the latest production techniques. Dievar has good heat-checking and gross-cracking resistance as a result of both high toughness and good hot strength. An additional material, a new prehardened tool steel known as TOOLOX 44, exhibits control of the failure described above by optimizing the parameters of impact toughness that could reduce the heat-checking failures. A variety of heat treatment parameters exist for various reasons because the heat treatment operation is performed by a variety of companies. This issue of the diversity in heat treatments is resolved by TOOLOX 44; this steel is quenched and tempered in delivered state.

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

    Aramouni, P; Millstein, P


    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.

  1. Heat Transfer between Casting and Dieduring High Pressure Die Casting Process of AM50 Alloy-Modeling and Experimental Results


    A method based on die casting experiments and mathematic modeling is presented for the determination of the heat flow density (HFD) and interfacial heat transfer coefficient (IHTC) during the high pressure die casting (HPDC) process. Experiments were carried out using step shape casting and a commercial magnesium alloy, AM50. Temperature profiles were measured and recorded using thermocouples embedded inside the die.Based on these temperature readings, the HFD and IHTC were successfully determined and the calculation results show that the HFD and IHTC at the metal-die interface increases sharply right after the fast phase injection process until approaching their maximum values, after which their values decrease to a much lower level until the dies are opened. Different patterns of heat transler behavior were found between the die and the castingat different thicknesses. The thinner the casting was, the more quickly the HFD and IHTC reached their steady states. Also, the values for both the HFD and IHTC values were different between die and casting at different thicknesses.

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

    Jerald Brevick; R. Allen Miller


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

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

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


    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.


    L. R. Dudetskaja


    Full Text Available The paper discusses distinctive design features of casting molds and technological aspects of producing cast inserts from 5ХНМЛ pressed steel. The designs of long-life metal shell molds are described. They ensure saving of molding material, increase of accepted material and improvement of quality of castings.

  5. Temperature change and stress distribution analysis of die surface in Al-alloy die casting process and experimental study on die heat check

    Hu Xinping; Zhao Guoqun; Wu Bingyao


    The temperature change of the die surface in practical aluminum alloy die casting process was analyzed,and a 2D model was formulated on the basis of a deep concave round cavity without sliding core to analyze the stress distributions along the die surface in detail. Equipment was designed to test the thermal state of the die steel in different thermal loading conditions. The results of stress analysis showed that, the value of thermal stress (maximum 1.5 GPa) caused in the die filling and die spraying stages was larger than the mechanical stress (maximum 85 MPa)caused in the die locking stage. The results of the thermal check experiment showed that there were three stages of die dissolving, and that the stress distribution shown by the samples' cracking routine was close to the die surface stress analysis.


    A. A. Pivovarchyk


    Full Text Available The paper presents the results of a study on the effect of a method for dispersing the size of the component of the dispersed phase separation coatings used in high pressure die casting aluminum alloys.


    A. Pivovarchik


    Full Text Available The paper presents the results of research on the study of the possibility of accumulation of the lubricating layer coating on the surface of the separation process of foundry equipment with high pressure die casting aluminum alloys.

  8. Die Casting Mold Design of the Thin-walled Aluminum Case by Computational Solidification Simulation

    Young-Chan Kim; Chang-Seog Kang; Jae-Ik Cho; Chang-Yeol Jeong; Se-Weon Choi; Sung-Kil Hong


    Recently, demand for the lightweight alloy in electric/electronic housings has been greatly increased. However, among the lightweight alloys, aluminum alloy thin-walled die casting is problematic because it is quite difficult to achieve sufficient fluidity and feedability to fill the thin cavity as the wall thickness becomes less than 1 mm. Therefore, in this study, thin-walled die casting of aluminum (Al-Si-Cu alloy: ALDC 12) in size of notebook computer housing and thickness of 0.8 mm was investigated by solidification simulation (MAGMA soft) and actual casting experiment (Buhler Evolution B 53D). Three different types of gating design, finger, tangential and split type with 6 vertical runners, were simulated and the results showed that sound thin-walled die casting was possible with tangential and split type gating design because those gates allowed aluminum melt to flow into the thin cavity uniformly and split type gating system was preferable gating design comparing to tangential type gating system at the point of view of soundness of casting and distortion generated after solidification. Also, the solidification simulation agreed well with the actual die-casting and the casting showed no casting defects and distortion.

  9. Focusing on Technology and Services, Competing in China Die Casting Market Report on visits with five companies participating in the Asia-Pacific Die Casting Industry Exhibition 2005


    @@ The Asia-Pacific Die Casting Industry Exhibition 2005, organized by Foundry Institution of Chinese Mechanical Engineering Society (FICMES), was held in INTEX Shanghai, China on August 14-17, 2005. On August 16th, the journalists of CHINA FOUNDRY journal visited five exhibitors on the spot of exhibition.

  10. New Trends of Die Casting Market in China——A Commentary on the 5th China International Die Casting Exhibition

    QU Xue-liang


    @@ The 5th China International Die Casting Exhibition, sponsored by Chinese Mechanical Engineering Society (CMES) and China Productivity Promotion Center of Machinery Industry, organized by Foundry Institution of Chinese Mechanical Engineering Society (FICMES) and China Productivity Promotion Center of Foundry Industry, was successfully held on June 28 to July 1,2006 in INTEX Shanghai, China.


    V. N. Kuzmich


    Full Text Available The main details of foundry equipment are developed. Analysis of the process of filling and hardening of casting “Transducer case” is carried out on the basis of methods of mathematic modeling of foundry processes.

  12. Study on Numerical Simulation of Mold Filling and HeatTransfer in Die Casting Process


    A 3-D mathematical model considering turbulence phenomena has been established basedon a computational fluid dynamics technique, so called 3-D SOLA-VOF (Solution Algorithm-Volume of Fluid), to simulate the fluid flow of mold filling process of die casting. In addition, the mathematical model for simulating the heat transfer in die casting process has also been established.The computation program has been developed by the authors with the finite difference method (FDM) recently. As verification, the mold filling process of a S-shaped die casting has been simulated and the simulation results coincide with that of the benchmark test. Finally, as a practical application, the gating design of a motorcycle component was modified by the mold filling simulation and the dies design of another motorcycle component was optimized by theheat transfer simulation. All the optimized designs were verified by the production practice.

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

    Sce, Andrea; Caporale, Lorenzo


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

  14. 3D scanning based mold correction for planar and cylindrical parts in aluminum die casting

    Takashi Seno


    Full Text Available Aluminum die casting is an important manufacturing process for mechanical components. Die casting is known to be more accurate than other types of casting; however, post-machining is usually necessary to achieve the required accuracy. The goal of this investigation is to develop machining- free aluminum die casting. Improvement of the accuracy of planar and cylindrical parts is expected by correcting metal molds. In the proposed method, the shape of cast aluminum made with the initial metal molds is measured by 3D scanning. The 3D scan data includes information about deformations that occur during casting. Therefore, it is possible to estimate the deformation and correction amounts by comparing 3D scan data with product computer-aided design (CAD data. We corrected planar and cylindrical parts of the CAD data for the mold. In addition, we corrected the planar part of the metal mold using the corrected mold data. The effectiveness of the proposed method is demonstrated by evaluating the accuracy improvement of the cast aluminum made with the corrected mold.

  15. Thin-Wall Aluminum Die-Casting Technology for Development of Notebook Computer Housing


    Silicon-based aluminum casting alloys are known to be one of the most widely used alloy systems mainly due to their superior casting characteristics and unique combination of mechanical and physical properties.However, manufacturing of thin-walled aluminum die-casting components, less than 1.0 mm in thickness, is generally known to be very difficult task to achieve aluminum casting alloys with high fluidity. Therefore, in this study, the optimal die-casting conditions for producing 297 mm×210 mm×0.7 mm thin-walled aluminum component was examined experimentally by using 2 different gating systems, tangential and split type, and vent design. Furthermore, computational solidification simulation was also conducted. The results showed that split type gating system was preferable gating design than tangential type gating system at the point of view of soundness of casting and distortion generated after solidification. It was also found that proper vent design was one of the most important factors for producing thin-wall casting components because it was important for the fulfillment of the thin-wall cavity and the minimization of the casting distortion.

  16. Numerical simulation and optimization of Al alloy cylinder body by low pressure die casting

    Mi Guofa


    Full Text Available Shrinkage defects can be formed easily at Critical location during low pressure die casting (LPDC of aluminum alloy cylinder body. It has harmful effect on the products. Mold fi lling and solidifi cation process of a cylinder body was simulated by using of Z-CAST software. The casting method was improved based on the simulation results. In order to create effective feeding passage, the structure of casting was modifi ed by changing the location of strengthening ribs at the bottom, without causing any adverse effect on the part’s performance. Inserting copper billet at suitable location of the die is a valid way to create suitable solidifi cation sequence that is benefi cial to the feeding. Using these methods, the shrinkage defect was completely eliminated at the critical location.

  17. Pressure die cast graphite dispersed Al-Si-Mg alloy matrix composites

    Pillai, U.T.S. (Regional Research Lab. (CSIR), Trivandrum (India)); Pai, B.C. (Regional Research Lab. (CSIR), Trivandrum (India)); Kelukutty, V.S. (Regional Research Lab. (CSIR), Trivandrum (India)); Satyanarayana, K.G. (Regional Research Lab. (CSIR), Trivandrum (India))


    An improvement in casting of aluminium alloy graphite particulate composite synthesized by stir casting is discussed. About 15 wt.% graphite particles were dispersed in Al-Si-Mg (LM 25) alloy by the rheocasting technique. The composite ingots were used as a master alloy and diluted further with LM 25 alloy to obtain a 5 wt.% dispersion of graphite in the matrix. The composite ingots thus processed were subsequently remelted and pressure die cast into plates. Macroscopic and microscopic examination of the plates revealed fewer defects and a fine distribution of particles. The ultimate tensile strength evaluated in this composite was superior (132-136 MPa) to that of gravity die cast (85-95 MPa) composites. The fracture toughness of the composites was in the range 8-10 MPa m[sup 1/2]. (orig.)

  18. Numerical simulation and optimization of Al alloy cylinder body by low pressure die casting

    Mi Guofa; Liu Yanlei; Zhao Hengtao; Fu Hengzhi


    Shrinkage defects can be formed easily at critical location during low pressure die casting(LPDC)of aluminum alloy cylinder body.It has harmful effect on the products.Mold filling and solidification process of a cylinder body was simulated by using of Z-CAST software.The casting method was Improved based on the simulation results.In order to create eriective feeding passage,the structure of casting was modified by changing the location of strengthening ribs at the bottom,without causing any adverse effect on the part's performance.Inserting copper billet at suitable Iocation of the die is a valid way to create suitable solidification sequence that is beneficial to the feeding.Using these methods.the shrinkage defect was completely eliminated at the critical location.

  19. Recycling of Al-Si die casting scraps for solar Si feedstock

    Seo, Kum-Hee; Jeon, Je-Beom; Youn, Ji-Won; Kim, Suk Jun; Kim, Ki-Young


    Recycling of aluminum die-casting scraps for solar-grade silicon (SOG-Si) feedstock was performed successfully. 3 N purity Si was extracted from A383 die-casting scrap by using the combined process of solvent refining and an advanced centrifugal separation technique. The efficiency of separating Si from scrap alloys depended on both impurity level of scraps and the starting temperature of centrifugation. Impurities in melt and processing temperature governed the microstructure of the primary Si. The purity of Si extracted from the scrap melt was 99.963%, which was comparable to that of Si extracted from a commercial Al-30 wt% Si alloy, 99.980%. The initial purity of the scrap was 2.2% lower than that of the commercial alloy. This result confirmed that die-casting scrap is a potential source of high-purity Si for solar cells.

  20. Influence of physical data and cooling conditions on the solidification of magnesium die castings


    As the simulation quality increases, the determination of hot spots is not enough to foundry engineers anymore. The simulation results have to fit in a quality way into the real foundry world. More and more results of the simulation will be used to optimise the casting process. Here it is necessary to have a very precise knowledge of the physical data. as well as the description of the geometry. To make use of the simulation in especially the magnesium-casting development it is necessary to work with precise geometrical, physical and numerical models. In this paper we describe the development of physical data concerning the heat transfer during filling and solidification by different casting methods. The low pressure as well as the gravity die casting method are used to get real data to find out the right conditions in the simulation in order to simulate the real behaviour during production. Practical tests are done under different test conditions to develop the right physical data as well as the right conditions in the metal-mould interface. The different surface conditions and the influence of the die and the molten metal temperatures are important for the layout of the die casting process. Three different shapes were applied to different mould materials and casting methods. The cooling conditions are tested on specific items. The cooling shape is not restricted by the drilling conditions. The effect of different cooling conditions are generated and measured. The results form the basis for the heat transfer conditions. These results are applied to real castings, cellular phone housings by low-pressure die casting process. The use of the new conditions leads to a good process description.

  1. Microstructure Characteristics of the Eutectics of Die Cast AM60B Magnesium Alloy

    Mengwu Wu; Shoumei Xiong


    Under the cold-chamber high pressure die casting (HPDC) process, samples were produced with AM60B magnesium alloy to investigate the microstructure characteristics of the eutectics, especially focusing on the constitution, morphology and distribution of the eutectics over cross section of the castings. Attentions were also paid to study the effect of heat treatment on the eutectics in the die castings. Based on experimental analysis using optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), it was determined that fully divorced eutectics consisting of a-Mg and β-Mg17Al12 appeared at the grain boundary of the primary α-Mg in the as-cast microstructure. Islands and networks of β-Mg17Al12 phase were observed in the central region of the castings, while the β-Mg17Al12 phase revealed a more dispersed and granular morphology on the surface layer. The two phases ratio β/α in the central region of the castings was approximately 10%, which was higher than that on the surface layer. Besides, the defect bands contained a higher percentage of the eutectics than the adjacent regions. After aging treatment (T6), only a-Mg phase was detected by XRD in the AM60B magnesium alloy, though a small amount of precipitated β-Mg17Al12 phase was observed at the grain boundary. In contrast to the microstructure of die cast AZ91D magnesium alloy under the same T6 heat treatment, no discontinuous precipitation of the β-Mg17Al12 phase was observed in AM60B magnesium alloy die castings.

  2. Design of Semi-Solid Die Casting Die for Box Shell and its Die Casting%盒体铸件半固态压铸模及压铸工艺研究

    赵艳红; 姚国海; 王淼


    设计并制造出盒体半固态压铸模,利用Flow-3D模拟软件对盒体半固态流变压铸充型及凝固过程进行了数值模拟,并进行了试验验证.结果表明,半固态压铸过程中,模具温度对半固态压铸影响较大.经过模拟优化的半固态压铸工艺参数:压射速度为1 m/s,模具预热温度为260℃,浆料温度为590℃.%The semi-solid die casting die for box shell was designed and manufactured.By using Flow-3D software,the filling and solidification process of semi-solid rheological die-casting was simulated,and verification experiment was conducted.The results show that the temperature of die has the obvious effects on semi-solid die casting process.The optimized parameters for semi-solid die casting were presented as follows:injection velocity of 1 m/s,pre-heating temperature of mould at 260 ℃ and slurry temperature of 590 ℃.

  3. Advanced metrology of surface defects measurement for aluminum die casting

    D. Myszka


    Full Text Available The scientific objective of the research is to develop a strategy to build computer based vision systems for inspection of surface defects inproducts, especially discontinuities which appear in castings after machining. In addition to the proposed vision inspection method theauthors demonstrates the development of the advanced computer techniques based on the methods of scanning to measure topography ofsurface defect in offline process control. This method allow to identify a mechanism responsible for the formation of casting defects. Also,the method allow investigating if the, developed vision inspection system for identification of surface defects have been correctlyimplemented for an online inspection. Finally, in order to make casting samples with gas and shrinkage porosity defects type, the LGT gas meter was used . For this task a special camera for a semi-quantitative assessment of the gas content in aluminum alloy melts, using a Straube-Pfeiffer method was used. The results demonstrate that applied solution is excellent tool in preparing for various aluminum alloysthe reference porosity samples, identified next by the computer inspection system.

  4. Microstructure and properties of cast iron by semi-solid die casting process; Hangyoko diecast shita chutetsu no soshiki to seishitsu

    Yoshida, C.; Kitamura, K.; Ando, Y.; Hironaka, K.


    In the semi-solid die casting process, products are made by processing metals in the liquid and solid coexistence region. Die casting experiments were conducted using flaky graphite cast iron by means of the rheocasting method in which semi-solid slurry is directly die cast and the thixocasting method in which raw material billet is heated up to the semi-solid temperature and then die cast. In both the methods, flat plates were produced. In the rheocasting with the solid ratio of 0.2, flat plates of 6 mm thick were obtained. The surface temperature of die was lower than that in the case of melt die casting, which reduced the heat load of die. The macro segregation was also reduced. In the thixocasting, flat plates of 3 mm thick were obtained. Using general flaky graphite cast iron, the microstructure was observed where solid phase austenite is uniformly dispersed in the solid-liquid coexistence region. Austenite and austenite/cementite eutectic was observed in the specimens without treatment after casting. Cementite easily changed into fine graphite spheres through the heat treatment, which has excellent tensile strength of 400 MPa and elongation of 3%. 7 refs., 12 figs., 5 tabs.

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

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


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

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

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


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

  7. Development of a high creep strength hot-chamber die-casting zinc alloy

    Goodwin, F.E. (International Lead Zinc Research Organization, Inc., Research Triangle Park, NC (United States))


    Alloys of Zn-0.3% Al-1.3% Cu-0.3% Mn-0.01% Mg were pressure die cast with Li levels of 0, 0.07, 0.13, and 0.19% Li. The creep properties of these alloys were between those of Zamak 5. and ILZRO 16. Immersion testing of die steel coupons in one of the Li-containing alloys showed rates of erosion similar to those known for Zamak alloys 3 and 5. The mechanism of impoved creep values in the Li-containing alloys appears to be Li-Zn compounds which at first are located on grain boundaries. After aging at 100deg C, they are found predominantly within the grains. Shortterm tensile properties of the Li-containing alloys are 75-85 percent of the properties of Zamak 5, except for the alloy containing the lowest amount of lithium. Elongation and impact values are low. The latter attribute may be caused by the high levels of Mn in these alloys, which form Al-Mn particles on grain boundaries. (orig.).

  8. Evolution of Intermetallic Phases in Soldering of the Die Casting of Aluminum Alloys

    Song, Jie; Wang, Xiaoming; DenOuden, Tony; Han, Qingyou


    Most die failures are resulted from chemical reactions of dies and molten aluminum in the die casting of aluminum. The formation of intermetallic phases between a steel die and molten aluminum is investigated by stationary immersion tests and compared to a real die casting process. Three intermetallic phases are identified in the stationary immersion tests: a composite layer and two compact layers. The composite layer is a mixture of α bcc, Al, and Si phases. The α bcc phase changes in morphology from rod-like to spherical shape, while the growth rate of the layer changes from parabolic to linear pattern with immersion time. The first compact layer forms rapidly after immersion and maintains a relatively constant thickness. The second compact layer forms after 4 hours of immersion and exhibits parabolic growth with immersion time. In comparison, only a composite layer and the first compact layer are observed in a real die casting process. The fresh molten aluminum of high growth rate washes away the second intermetallic layer easily.

  9. Study on interfacial heat transfer coefficient at metal/die interface during high pressure die casting process of AZ91D alloy

    GUO Zhi-peng


    Full Text Available The high pressure die casting (HPDC process is one of the fastest growing and most efficient methods for the production of complex shape castings of magnesium and aluminum alloys in today’s manufacturing industry.In this study, a high pressure die casting experiment using AZ91D magnesium alloy was conducted, and the temperature profiles inside the die were Measured. By using a computer program based on solving the inverse heat problem, the metal/die interfacial heat transfer coefficient (IHTC was calculated and studied. The results show that the IHTC between the metal and die increases right after the liquid metal is brought into the cavity by the plunger,and decreases as the solidification process of the liquid metal proceeds until the liquid metal is completely solidified,when the IHTC tends to be stable. The interfacial heat transfer coefficient shows different characteristics under different casting wall thicknesses and varies with the change of solidification behavior.

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

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


    The utilization of aluminum die casting as enclosures where internal equipment is rotating inside of the casting and could fracture requires a strong housing to restrain the fractured parts. A typical example would be a supercharger. In case of a failure, unless adequately contained, fractured parts could injure people operating the equipment. A number of potential reinforcement materials were investigated. The initial work was conducted in sand molds to create experimental conditions that promote prolonged contact of the reinforcing material with molten aluminum. Bonding of Aluminum bronze, Cast iron, and Ni-resist inserts with various electroplated coatings and surface treatments were analyzed. Also toughening of A354 aluminum cast alloy by steel and stainless steel wire mesh with various conditions was analyzed. A practical approach to reinforcement of die cast aluminum components is to use a reinforcing steel preform. Such performs can be fabricated from steel wire mesh or perforated metal sheet by stamping or deep drawing. A hemispherical, dome shaped casting was selected in this investigation. A deep drawing die was used to fabricate the reinforcing performs. The tendency of aluminum cast enclosures to fracture could be significantly reduced by installing a wire mesh of austenitic stainless steel or a punched austenitic stainless steel sheet within the casting. The use of reinforcements made of austenitic stainless steel wire mesh or punched austenitic stainless steel sheet provided marked improvement in reducing the fragmentation of the casting. The best strengthening was obtained with austenitic stainless steel wire and with a punched stainless steel sheet without annealing this material. Somewhat lower results were obtained with the annealed punched stainless steel sheet. When the annealed 1020 steel wire mesh was used, the results were only slightly improved because of the lower mechanical properties of this unalloyed steel. The lowest results were

  11. Numerical simulation of mold-filling capability for a thin- walled aluminum die casting

    Sun, L.; Subasic, E.; Jakumeit, J.


    Mold-filling capability is an important property of casting materials. Especially in thin-walled die casting, fast cooling of the melt by contact to the die makes complete filling difficult to ensure. Simulation is an important tool enabling investigation of filling problems, even before the die is manufactured. However, the prediction of misruns is challenging. Flow and solidification have to be computed as closely coupled. The effects of surface tension, the wetting angle and reduced melt flow due to solidification must be modeled with high precision. To meet these requirements, a finite-volume method using arbitrary polyhedral control volumes is used to solve flow and solidification as closely coupled. The Volume-of-Fluid approach is used to capture the phase separation between gas, melt and solid in connection with a High-Resolution Interface-Capturing scheme to obtain sharp interfaces between phases. To model the resistance of the dendrite network to the melt flow, an additional source term in the momentum equation was implemented. The Bolt test was performed for A356 alloys at a range of different casting temperatures. Numerical prediction of incomplete filling in the bottleneck regions agreed well with experimental findings using 3D camera scanning. The simulation enables derivation of the dependence of critical wall-thickness, i.e. the thickness which is fillable, on casting temperature and metallostatic pressure. This could prove useful in predicting filling problems ahead of casting.

  12. Application of laser additive manufacturing to produce dies for aluminium high pressure die casting

    Pereira, MFVT


    Full Text Available to significant time- and cost-saving during product or process developments. Based on these findings, a number of recommendations are made for users interested in the application of LAM to produce die cavities....

  13. Experimental Damage Criterion for Static and Fatigue Life Assessment of Commercial Aluminum Alloy Die Castings

    Battaglia, Eleonora; Bonollo, Franco; Ferro, Paolo


    Defects, particularly porosity and oxides, in high-pressure die casting can seriously compromise the in-service behavior and durability of products subjected to static or cyclic loadings. In this study, the influence of dimension, orientation, and position of casting defects on the mechanical properties of an AlSi12(b) (EN-AC 44100) aluminum alloy commercial component has been studied. A finite element model has been carried out in order to calculate the stress distribution induced by service loads and identify the crack initiation zones. Castings were qualitatively classified on the basis of porosities distribution detected by X-ray technique and oxides observed on fracture surfaces of specimens coming from fatigue and tensile tests. A damage criterion has been formulated which considers the influence of defects position and orientation on the mechanical strength of the components. Using the proposed damage criterion, it was possible to describe the mechanical behavior of the castings with good accuracy.

  14. Tribological Properties of AlSi11-SiCp Composite Castings Produced by Pressure Die Casting Method

    Konopka Z.


    Full Text Available The measurement results concerning the abrasive wear of AlSi11-SiC particles composites are presented in paper. The method of preparing a composite slurry composed of AlSi11 alloy matrix and 10, 20% vol.% of SiC particles, as well as the method of its high-pressure die casting was described. Composite slurry was injected into metal mould of cold chamber pressure die cast machine and castings were produced at various values of the piston velocity in the second stage of injection, diverse intensification pressure values, and various injection gate width values. Very good uniform arrangement of SiC particles in volume composite matrix was observed and these results were publicated early in this journal. The kinetics of abrasive wear and correlation with SiC particles arrangement in composite matrix were presented. Better wear resistance of composite was observed in comparison with aluminium alloy. Very strong linear correlation between abrasive wear and particle arrangement was observed. The conclusion gives the analysis and the interpretation of the obtained results.

  15. Understanding of the influence of process parameters on the heat transfer behavior at the metal/die inter-face in high pressure die casting process

    GUO ZhiPeng; XIONG ShouMei; LIU BaiCheng; LI Mei; Allison John


    The current paper focuses on the influence of the process parameters on the peak values of the inter-facial heat transfer coefficient (IHTC) at metal/die interface during high pressure die casting (HPDC) process. A "step shape" casting and AM50 alloy were used during the experiment. The IHTC was de-termined by solving the inverse thermal problem based on the measured temperature inside the die. Results show that the initial die surface temperature (IDST, TDI) has a dominant influence while the casting pressure and fast shot velocity have a secondary influence on the IHTC peak values. By curve fitting, it was found that the IHTC peak value (hmax) changes as a function of the IDST in a manner of hmax=eαTγDI. Such relationship between the IHTC peak value and the IDST can also be found when the casting alloy is ADC12, indicating that this phenomenon is a common characteristic in the HPDC process.

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

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


    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%, respectively. With further increase of chromium and molybdenum contents, chromium slightly reduces the wear resistance and molybdenum severely deteriorates the wear resistance with high wear rate. Lower vanadium/carbon ratio (1.5-2.5) leads to a lower wear resistance with higher wear rate. With an increase in vanadium/carbon ratio, the wear resistance of the cast steel substantially increases. When vanadium/carbon ratio is 3, the wear rate reaches the lowest value. The predominant mechanism of thermal wear of cast hot-forging die steels are oxidation wear and fatigue delamination. The Fe2O3 and Fe3O4 or lumps of brittle wear debris are formed on the wear surface.

  17. High cycle fatigue properties of die-cast magnesium alloy AZ91D-1%MM


    The high cycle fatigue properties of the die-cast magnesium alloy AZ91D containing 1%mischmetal(mass fraction)at a fatigue ratio of 0.1 were investigated.The difference in the microstructure between the skin and core region of the die-cast magnesium alloy was analyzed by optical microscopy.The mechanical property tests indicate that the values of the tensile strength,elongation and hardness are 185 MPa,1.5%and HBS 70±3 at room temperature,respectively.The p-S-N curve(p=50%)of the die-cast magnesium alloy AZ91D-1%MM is determined and the mean fatigue strength corresponding to 3.8×105cycles is 70 MPa.A linear relation between S and Np in log scale between 103 and 106 cycles is written with a equation.The mechanical properties are influenced by the casting defects.The fatigue life of the samples with minor defects is near to the upper limit of the fatigue life data.The fatigue fracture surface of the samples with minor defects possesses the mixed characteristics of quasi-cleavage,lacerated ridge and dimple and it is briule fracture mode as a whole.

  18. Modelling of Filling, Microstructure Formation, Local Mechanical Properties and Stress – Strain Development in High-Pressure Die Cast Aluminium Castings

    Kotas, Petr; Hattel, Jesper Henri; Thorborg, Jesper


    inherently affects the component’s properties depending on design, metallurgy and casting technique. The wall thickness influences the coarseness of the microstructure and the material will have properties depending on the local metallurgical and thermal histories. This is independent on the material, i.......e. whether the casting is based on cast iron- or aluminium-alloys. The distribution of local properties in a casting might vary substantially which makes it complex to optimize the casting with good accuracy. Often, mechanical simulations of the load situation are based on the assumption that the cast...... product has constant material properties throughout the entire casting. Thus, if the microstructure is determined or predicted at a given point, it gives the possibility to calculate the local material behavior more realistically. In the present work, a test case of a complex high-pressure die cast part...

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

    David Schwam


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

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

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


    Computer software for the numerical simulation of solidification and mold filling is an effective design tool for cast structural automotive magnesium components. A review of commercial software capabilities and their validation procedures was conducted. Aside form the software assessment, the program addressed five main areas: lubricant degradation, lubricant application, gate atomization, and heat transfer at metal mold interfaces. A test stand for lubricant application was designed. A sensor was used for the direct measurement of heat fluxes during lubricant application and casting solidification in graphite molds. Spray experiments were conducted using pure deionized water and commercial die lubricants. The results show that the sensor can be used with confidence for measuring heat fluxes under conditions specific to the die lube application. The data on heat flux was presented in forms suitable for use in HPDC simulation software. Severe jet breakup and atomization phenomena are likely to occur due to high gate velocities in HPDC. As a result of gate atomization, droplet flow affects the mold filling pattern, air entrapment, skin formation, and ensuing defects. Warm water analogue dies were designed for obtaining experimental data on mold filling phenomena. Data on break-up jet length, break-up pattern, velocities, and droplet size distribution were obtained experimentally and was used to develop correlations for jet break-up phenomena specific to die casting gate configurations.

  1. Study of Nozzle and Vent Locations on Die Casting Filling Process


    The casting nozzle location plays an important role in die casting. Improper location results in defects, such as cold shut, air cavity, shrinkage, etc. Therefore, it's sure that the molten metal full fills the mould cavity before it solidifies. And, it's to be wished that no vortex occur during the filling process, because the vortex is a main source that induces gas entrapment. To get the high quality and performance product, the inlet and outlet locations must be set properly. This paper, an optimal desi...

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

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


    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.

  3. Effect of Multipoint Sequential Water Mist Cooling of Casting Die on Microstructure and Mechanical Properties of AlSi11 Alloy

    Władysiak R.


    Full Text Available The work is a continuation of research on the use of water mist cooling in order to increase efficiency of the die-casting process for aluminum alloys. The paper describes the multipoint sequential cooling system of the casting die and its computer control and monitoring. It also includes results of the tests and analysis of cooling methods during making of the casting. These methods differ from each other in the sequence of casting die cooling and cause effective changes in microstructure and mechanical properties of castings made of AlSi11 alloy. The study demonstrated that the use of multipoint sequential cooling with water mist affects the microstructure refinement and reduces the segregation in the cast as well as more than by 20% increases the mechanical properties of castings in the rough state. The study also demonstrates that the sequential cooling of casting die accelerates the cooling of the casting and shortens die-casting cycle.

  4. Effect of Multipoint Sequential Water Mist Cooling of Casting Die on Microstructure and Mechanical Properties of AlSi11 Alloy

    R. Władysiak


    Full Text Available The work is a continuation of research on the use of water mist cooling in order to increase efficiency of the die-casting process for aluminum alloys. The paper describes the multipoint sequential cooling system of the casting die and its computer control and monitoring.It also includes results of the tests and analysis of cooling methods during making of the casting. These methods differ from each other in the sequence of casting die cooling and cause effective changes in microstructure and mechanical properties of castings made of AlSi11 alloy. The study demonstrated that the use of multipoint sequential cooling with water mist affects the microstructure refinement and reduces the segregation in the cast as well as more than by 20% increases the mechanical properties of castings in the rough state. The study also demonstrates that the sequential cooling of casting die accelerates the cooling of the casting and shortens die-casting cycle.

  5. Improvement of quality of a gravity die casting made from aluminum bronze be application of numerical simulation

    A. Fajkiel


    Full Text Available The paper describes the possibility of improving the quality of gravity die cast connectors for overhead power transmission lines. The castings were made from aluminum bronze, grade CuAl9Fe1Ni1. A MAGMAsoft computer programme was used for simulation of the process of die filling and casting solidification to avoid defects, like shrinkage depression and gas porosities. The results of the simulation have finally led to redesigning of the metal feeding and cooling system and to reduced level of defects in castings.

  6. Development and Application of Die-Casting High Speed Steel Rolls

    JIANG Zhi-qiang; FU Han-guang; DING Yu-cheng


    Due to its high hardness, good red hardness and excellent wear resistance at high temperature, high speed steel (HSS) is fit for the roll manufacture. In order to overcome the segregation of centrifugal casting of HSS roll, die-cast processes were developed and its effects on the properties of the HSS roll were investigated. It was found that pressure, pressing time and speed are three important factors affecting shrinkage cavity. For pouring temperature of 1 400-1 450 ℃, pressure of 150-160 MPa, pressing time of 120-150 s and pressing speed of 14-16 mm/s, a compact HSS roll was obtained, which has no segregation and small working allowance. In the high speed wire rod rolling mill, service life of the HSS roll is 5 to 8 times longer than that of high nickel chromium infinite chilled cast iron roll.

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

    Niklas, Frank; Schneider, Wolfgang


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

  8. Optimization design for gating system in die-casting die%压铸模浇注系统的优化设计



      应用CAE软件对压铸件的成型过程进行模拟,根据模拟的结果,对压铸模浇注系统进行优化,改善模具的浇注系统结构,提高了压铸件品质。%The forming process for a die-casting part was simulated by applying CAE soft⁃ware. The gating system in die-casting die was optimized in accordance with the simula⁃tion results and the structure of gating system was improved and the quality of die-casting parts was enhanced.

  9. Influence of samarium content on microstructure and mechanical properties of recycled die-cast YL112 aluminum alloys

    Zhi Hu


    Full Text Available The influence of Sm (Samarium content on microstructure and mechanical properties of recycled die-cast YL112 aluminum alloys was investigated. The results show that many small Sm-rich particles form in the recycled die-cast YL112 alloys with Sm addition. At the same time, the secondary dendrite arm spacing in the YL112 alloys modified with Sm is smaller than that of the unmodified alloy. The eutectic Si of recycled die-cast YL112-xSm alloys transforms from coarse acicular morphology to fine fibres. Mechanical properties of the investigated recycled die-cast YL112 aluminum alloys are enhanced with Sm addition, and a maximal ultimate tensile strength value (276 MPa and elongation (3.76% are achieved at a Sm content of 0.6wt.%. Due to the modification of eutectic Si by Sm, numerous tearing ridges and tiny dimples on the fractures of tensile samples are observed.

  10. Grain refinement of ASTM A356 aluminum alloy using sloping plate process through gravity die casting

    Adnan Mehmood


    Full Text Available Sloping plate flow is used for enhancement of material properties through grain refinement in gravity die casting of Aluminum alloy ASTM A356. The castings are prepared with different slope angles of an 800 mm long, naturally cooled stainless steel plate. The specimens obtained are then tested for tensile strength and elongation. Microstructure of the cast specimens is observed and conclusions drawn on the grain size and precipitate morphology as a function of angle of sloping plate. Analysis is presented for the boundary layer created while the material flows over the plate. An indication of the boundary layer thickness is determined by measuring the thickness of the residual metal layer on the plate after casting. An analytical solution of the boundary layer thickness is also presented. It is shown that the calculated boundary layer thickness and the thickness of the layer of material left in the channel after casting are in good agreement. Moreover, microstructure examination and tensile tests show that best properties are achieved with a 60° sloping plate.

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

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


    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

  12. Analog Studies of Thermomechanical Fatigue and Abrasive Wear of Cast and Forged Steels for "Autoforge" Dies

    Kolesnikov, M. S.; Mironova, Yu. S.; Mukhametzyanova, G. F.; Novikova, I. E.; Novikov, V. Yu.


    Processes of thermomechanical fatigue and abrasive wear of suspension-cast precipitation-hardening ferrite-carbide steel 30T6NTiC-1.5 and standard steel 4Kh5MFS are studied. The dominant kinds of fracture typical for dies for semisolid stamping are determined. The factors and parameters of cyclic temperature and force loading are shown to produce a selective action on the competing kinds of damage of the die steels. A comparative analysis of the properties of the steels is performed. Steel 30T6NTiC-1.5 is shown to have substantial advantages over steel 4Kh5FMS traditionally used for making "Autoforge" dies.

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

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


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

  14. Water mist effect on cooling range and efficiency of casting die

    R. Władysiak


    Full Text Available This project is showing investigation results of cooling process of casting die in the temperature range 570÷100 °C with 0.40 MPa compressed air and water mist streamed under pressure 0.25÷0.45 MPa in air jet 0.25÷0.50 MPa using open cooling system.The character and the speed of changes of temperature, forming of the temperture’s gradient along parallel layer to cooled surface of die is shawing with thermal and derivative curves. The effect of kind of cooling factor on the temperature and time and distance from cooling nozzle is presented in the paper. A designed device for generating the water mist cooling the die and the view of sprying water stream is shown here. It’s proved that using of the water mist together with the change of heat transfer interface increases intensity of cooling in the zone and makes less the range cooling zone and reduces the porosity of cast microstructure.

  15. Design of Die-casting Die and Analysis of Die Distortion%压铸模具设计及其变形分析

    潘宏歌; 魏家鹏


    The port plate was technologically analysed and the its die-casting mold was designed. By using Pro/Mechanic, which was the structural analysis module of Pro/E, the distortion induced by multi-stress in the working of the dies was analyzed. The results show that the die distortion is caused by the dilating force and thermal stress generated by the temperature load, and temperature load is the dominant factor leading to the mold deformation.%以配流盘为例,对其进行工艺分析,并设计压铸模具.同时,利用Pro/E软件的结构分析模块Pro/Mechanic,对模具在工作中承受的多方应力所产生的变形情况进行了分析.结果表明,胀型力和温度载荷所产生的热应力均会引起模具变形,其中,温度载荷是导致模具变形的主导因索.

  16. Determining the optimal index of heat stress in foundry, die casting and road construction industries using FAHP_Topsis

    Maryam Dehghanipoor


    Full Text Available Introduction: Heat stress is one of the harmful risks in casting and die casting industries, which can not only cause work-related diseases but also can impair the performance and safety of workers. Since the indicators that are used to evaluate heat stress are very different, it is very difficult to choose a suitable index. The aim of this study was to determine the optimum heat stress index in foundry, die-cast, and road construction industries using FAHP and Topsis methods. Material and Method: In order to determine optimum heat stress index in foundry, die-cast, and road construction industries, first, the prioritization criteria were defined by experts (including ease of measurement, measurement accuracy, comprehensiveness, time, cost, and correlation. Then, considering these criteria, the best heat stress index was determined based on experts’ opinions and using FAHP and Topsis methods. Result: The results of this study suggest that given the current conditions and criteria, WBGT and P4SR is the best indices for foundry, die casting and construction. Conclusion: The results showed that according to comprehensiveness, accuracy and correlation criteria, the WBGT index is considered as the best indicator of heat stress assessment in foundry, die-cast and road construction industries. Moreover, the HSI ranked in the last place due to the complexity and cost of its calculation.

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

    Borkowski, Stanisław; Czajkowska, Agnieszka; Stasiak-Betlejewska, Renata; Borade, Atul B.


    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.

  18. Influence of neodymium on high cycle fatigue behavior of die cast AZ91D magnesium alloy

    杨友; 李雪松


    High cycle fatigue behavior of die cast AZ91D magnesium alloy with different Nd contents was investigated.Axial mechanical fatigue tests were conducted at the stress ratio R=0.1 and the fatigue strength was evaluated using up-to-down load method on specimens of AZ91D with different Nd contents.The results showed that the grain of AZ91D alloy was refined,the size and amount of β-Mg17Al12 phase decreased and distributed uniformly with increasing Nd content.At the number of cycles to failure,Nf=107,the fatigue...

  19. Polymer melt rheology and flow simulations applied to cast film extrusion die design: An industrial perspective

    Catherine, Olivier


    This article is an overview of the techniques used today in the area of rheology and flow simulation, on the industrial level, for cast film extrusion die design. This industry has made significant progress over the past three decades and die and feedblock design and optimization certainly have been instrumental in the overall improvement. Dies and coextrusion feedblocks are a critical aspect of the process due to the layering and forming function, which drive the final product economics and properties. Polymer melt rheology is a key aspect to consider when optimizing the flow patterns in the extrusion equipment. Not only is rheology critical for the flow channel design when aiming at obtaining a uniform flow distribution at the die exit, but also it is playing a major role in the thermal aspect of the flow due to the strong mechanical and thermal coupling. This coupling comes, on one hand, from the occurrence of viscous dissipation in the flow and on the other hand from the significant temperature dependency of melt viscosity. Viscous dissipation is due to relatively high melt viscosities and strain rates, especially with today's processes which involve formidable extrusion speeds. The third aspect discussed in this paper is the complexity of residence time distribution in modern flow channels, which is evaluated with advanced three-dimensional flow simulation and particle tracking.

  20. Neuro-Knowledge-Based Expert System (NKBES)for Optimal Scheming of Die Casting Process

    Qiaodan HU; Peng LUO; Yi YANG; Liliang CHEN


    We develop a neuro-knowledge-based expert system (NKBES) frame in this work. The system mainly concerns with decision of gating system and die casting machine based on a neuro-inference engine launched under the MATLAB software environment. For enhancement of reasoning agility, an error back-propagation neural network was applied.A rapidly convergent adaptive learning rate (ALR) and a momentum-based error back-propagation algorithm was used to conduct neuro-reasoning. The working effect of the system was compared to a conventional expert system that is based on a two-way (forward and backward) chaining inference mechanism. As the reference, the present paper provided the neural networks sum-squared error (SSE) and ALR vs iterative epoch curves of process planning case mentioned above. The study suggests that the neuro-modeling optimization application to die casting process design has good feasibility, and based on that a novel and effective intelligent expert system can be launched at low cost.


    Javedhusen Malek


    Full Text Available In today's ever-changing customer driven market, industries are needed to improve their products and processes to satisfy customer requirements. The Six Sigma approach has set a new paradigm of business excellence. Six Sigma as a process driven improvement methodology has been adopted successfully by many industries. From the review of various literatures, it is revealed that Six Sigma is well adopted in large scale enterprise but having less evidence of adoption in Indian SMEs. This paper is focused on providing path to Indian SMEs for initiating Six Sigma approach in their industries. The paper discusses the real life case where Six Sigma has been successfully applied at one of the Indian small-scale unit to improve rejection/rework rate in manufacturing products by pressure die casting process. This paper describes phase wise application of all the phases of define-measure-analyse-improve-control (DMAIC which also shows impact of Six Sigma in quality improvement.

  2. A process chain for integrating piezoelectric transducers into aluminum die castings to generate smart lightweight structures

    Stein, Stefan; Wedler, Jonathan; Rhein, Sebastian; Schmidt, Michael; Körner, Carolin; Michaelis, Alexander; Gebhardt, Sylvia

    The application of piezoelectric transducers to structural body parts of machines or vehicles enables the combination of passive mechanical components with sensor and actuator functions in one single structure. According to Herold et al. [1] and Staeves [2] this approach indicates significant potential regarding smart lightweight construction. To obtain the highest yield, the piezoelectric transducers need to be integrated into the flux of forces (load path) of load bearing structures. Application in a downstream process reduces yield and process efficiency during manufacturing and operation, due to the necessity of a subsequent process step of sensor/actuator application. The die casting process offers the possibility for integration of piezoelectric transducers into metal structures. Aluminum castings are particularly favorable due to their high quality and feasibility for high unit production at low cost (Brunhuber [3], Nogowizin [4]). Such molded aluminum parts with integrated piezoelectric transducers enable functions like active vibration damping, structural health monitoring or energy harvesting resulting in significant possibilities of weight reduction, which is an increasingly important driving force of automotive and aerospace industry (Klein [5], Siebenpfeiffer [6]) due to increasingly stringent environmental protection laws. In the scope of those developments, this paper focuses on the entire process chain enabling the generation of lightweight metal structures with sensor and actuator function, starting from the manufacturing of piezoelectric modules over electrical and mechanical bonding to the integration of such modules into aluminum (Al) matrices by die casting. To achieve this challenging goal, piezoceramic sensors/actuator modules, so-called LTCC/PZT modules (LPM) were developed, since ceramic based piezoelectric modules are more likely to withstand the thermal stress of about 700 °C introduced by the casting process (Flössel et al., [7]). The

  3. Influence of the casting material on the dimensional accuracy of dental dies

    Daher Antonio Queiroz


    Full Text Available The purpose of this study was to evaluate the dimensional accuracy of different materials used in the confection of dies. Two stainless steel standard models were confected. One of the models, which was 2 mm larger than the other model, was used to provide a uniform relief for the two-step putty-wash impression technique. Thirty impressions were obtained using a polyvinyl siloxane impression material and randomly divided into three groups (n = 10 according to the type of casting material: type IV dental stone, commercially available epoxy resin (Tri-Epoxy, and industrial epoxy resin (Sikadur. After the setting/polymerization of the casting material, the dimensional stability was measured in terms of the height, diameter of the base and diameter of the top from the obtained dies and from the standard metal model using a profile projector. Results were analyzed by ANOVA and Dunnet test (α = 0.05. In the height values, no significant difference was observed between the groups, except for Sikadur casts, which showed lower mean values. The Tri-Epoxi group showed statistically lower mean base diameter values, compared with the other groups, and both epoxy resin groups showed statistically lower mean top diameter values, compared with that for the type IV dental stone group. We concluded that type IV gypsum and the commercially available epoxy resin showed similar behavior in most areas. The industrial epoxy resin did not show the same characteristics, although the diameter of the base obtained with it was similar to that obtained with type IV dental stone.

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

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


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

  5. Case study of lean manufacturing application in a die casting manufacturing company

    Ching, Ng Tan; Hoe, Clarence Chan Kok; Hong, Tang Sai; Ghobakhloo, Morteza; Pin, Chen Kah


    The case study of lean manufacturing aims to study the application of lean manufacturing in a die casting manufacturing company located in Pulau Penang, Malaysia. This case study describes mainly about the important concepts and applications of lean manufacturing which could gradually help the company in increasing the profit by studying and analyzing their current manufacturing process and company culture. Many approaches of lean manufacturing are studied in this project which includes: 5S housekeeping, Kaizen, and Takt Time. Besides, the lean tools mentioned, quality tool such as the House of Quality is being used as an analysis tool to continuously improve the product quality. In short, the existing lean culture in the company is studied and analyzed, with recommendations written at the end of this paper.

  6. A Numerical and Experimental Study of Flow Behavior in High Pressure Die Casting

    Saeedipour, Mahdi; Schneiderbauer, Simon; Pirker, Stefan; Bozorgi, Salar

    High pressure die casting (HPDC) is one of the most important and yet little known manufacturing methods especially during liquid metal injection and filling phase. During its application different problems can arise: on the one hand, wavy disintegration of the jet might result in cold shut defect in the final product, on the other hand a high degree of atomization may strongly increase the porosity defect. A numerical simulation using volume of fluid approach (VOF), is carried out to model the global spreading of liquid metal jet. The formation of droplets, which are usually smaller than the grid spacing in computational domain, is determined by a surface energy-based criterion. An Eulerian-Lagrangian framework is introduced to track and model the droplets after formation. Since liquid metal is hardly to access, we performed experiments based on water analogy to capture the flow regime changes and drop formation. The comparison between numerical results and experiments shows a very good agreement.

  7. Barium phosphate conversion coating on die-cast AZ91D magnesium alloy


    Poor corrosion resistance limits the application of magnesium alloys.Conversion coating is widely used to protect magnesium alloys because of easy operation and low cost.A novel conversion coating on die.cast AZ91D magnesium alloy containing barium salts was studied.The optimum concentrations of Ba(NO3)2,Mn(NO3)2 and NH4H2PO4 are 25 g/L,15 mL/L and 20 g/L,respectively,based on orthogonal test resulm.The treating time,solution temperature and PH value are settled to be 5-30 min,50-70℃and 2.35-3.0.respectively.The corrosion resistance of barium conversion coating is better than that of manganese-based phosphate conversion coating by immersion test.The coating is composed of Ba,P, O,Mg,Zn,Mn and Al by EDX analysis.

  8. Modification of Magnesium Alloys by Ceramic Particles in Gravity Die Casting

    Urs Haßlinger


    Full Text Available A critical drawback for the application of magnesium wrought alloys is the limited formability of semifinished products that arises from a strong texture formation during thermomechanical treatment. The ability of second phase particles embedded into the metal matrix to alter this texture evolution is of great interest. Therefore, the fabrication of particle modified magnesium alloys (particle content 0.5–1 wt.-% by gravity die casting has been studied. Five different types of micron sized ceramic powders (AlN, MgB2, MgO, SiC, and ZrB2 have been investigated to identify applicable particles for the modification. Agglomeration of the particles is revealed to be the central problem for the fabrication process. The main factors that influence the agglomerate size are the particle size and the intensity of melt stirring. Concerning handling, chemical stability in the Mg-Al-Zn alloy system, settling and wetting in the melt, and formation of the microstructure in most cases, the investigated powders show satisfying properties. However, SiC is chemically unstable in aluminum containing alloys. The high density of ZrB2 causes large particles to settle subsequent to stirring resulting in an inhomogeneous distribution of the particles over the cast billet.

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

    Lee, Soon Gi

    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.

  10. Failure behavior of high pressure die casting AZ91D magnesium alloy

    Li, X.; Xiong, S.M. [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Tsinghua University, Beijing 100084 (China); Guo, Z., E-mail: [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Tsinghua University, Beijing 100084 (China)


    The failure behavior of high pressure die casting AZ91D magnesium alloy during both tensile and fatigue tests was studied in situ by using scanning electron microscope. Attention was focused on the role of microstructure played in crack initiation and propagation. Results showed that the defects in castings, including gas pore, shrinkage pore and defect band, were the crack initiation sources. In tensile test, the crack propagated in a combination of intergranular and transgranular modes, and the specimen fractured by connecting defects at the section with minimum effective force bearing area. In fatigue test, the crack propagated in a transgranular mode at specific crystalline planes. When the crack was in contact with the β-phase, the crack would pass through, and fracture the network β-phase, whereas bypass the island β-phase by detaching it from the surrounding α-Mg grains. Besides, defects in front of the crack would act as the secondary crack initiation sources, from which new cracks would initiate and propagate. With the propagation of the fatigue crack, the actual maximum cyclic stress would increase to the fracture stress of the left cross section and lead to the final fracture of the specimen.

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

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

    It is well known that magnesium alloys, in close proximity to other alloys, are susceptible to galvanic corrosion. Combined with this fact, in automotive applications, it is rare that magnesium will be present in the absence of other alloys such as steel or aluminum. Therefore, in wet applications, where the galvanic cell is completed, it is necessary to isolate the magnesium in order to prevent accelerated corrosion. There are numerous commercial pre-treatments available for magnesium, however this paper focuses on conversion coatings in conjunction with a spray powder coat. By means of example, results for a hem flange joint on an AM50 die cast magnesium door structure will be presented. The outer door skin is an aluminum alloy hemmed around a cast magnesium flange. An adhesive is used between the inner and outer to help with stiffness and NVH (Noise, Vibration and Harshness). Results from bonded lap-shear coupon tests that have been exposed to accelerated corrosion cycles are presented. A second phase of this work considered a surrogate hem flange coupon, which was similarly exposed to the same accelerated corrosion cycle. Results from both of these tests are presented within this paper along with a discussion as to their suitability for use within automotive applications.

  12. The ‘full sleeve’ application in the horizontal cold-chamber machine for pressure die casting of aluminium alloys

    Z. Konopka


    Full Text Available The ‘full sleeve’ construction has been designed and accomplished in the horizontal cold-chamber pressure die casting machine. Main part of this solution is a counter plunger placed in a movable die half which allows for full filling of the shot sleeve and precisely fixes the metal quantity needed for casting. The purpose of this new construction solution is mainly the reduction of the casting porosity caused by air entrapment and the improvement of both castability and accuracy of the die cavity reproduction. For such a redesigned machine there have been performed examinations consisting in pressure casting of AlSi9Cu alloy (EN AC-46000 at varying plunger velocity in the second stage of injection and varying intensification pressure. The alloy castability (the die filling ability has been measured for each parameter setting. For the purpose of comparison, similar measurements have been performed also for the conventional system without a counter plunger. The castability examination has been done by means of a specially designed die with an impression of a trial casting of variable wall thickness. The experiments have been held according to the assumed factor design 22, what allowed for determining the mathematical models describing the influence of die filling parameters on the castability and the die cavity reproduction level. Both alternatives of the experiment confirmed the positive influence of plunger velocity and intensification pressure increase on the improvement of castability, the measure of the latter being the filled length of the impression. Applying of the new ‘full sleeve’ solution has improved castability for each experiment by about 20% as compared with conventional alternative. Castability in the ‘full sleeve’ system has been increased even for low values of plunger velocity and intensification pressure. For both alternative systems the influence of plunger velocity has been found, as an average, by four times

  13. A 1-D Analytical Model for the Thermally Induced Stresses in the Mould Surface During Die Casting

    Hattel, Jesper; Hansen, Preben


    This paper presents an anlytically based method for predicting the normal stresses in a die mold surface exposed to a thermal load. A example of application of the method is the high-pressure di casting process where the surface stresses in critical cases lead to cracks. Expressions for the normal...

  14. A three-die cast technique for duplicating free gingival form in zirconia crowns: two case reports.

    Nozawa, Takeshi; Tanaka, Koji; Tsurumaki, Shunzo; Ookame, Yasuhisa; Enomoto, Hiroaki; Ito, Koichi


    This report describes a duplication technique of free gingival form from a provisional restoration to a zirconia crown. Three die casts were manufactured from a silicone impression with an acrylic resin ring tray. The first die cast was for the zirconia framework, the second for the provisionalized transfer coping, and the third for relining the provisional restoration. A free gingival impression was taken using a provisionalized transfer coping, and a soft gingival cast was manufactured. The depth of free gingival transparency was measured using a zirconia shade plate. Then, the zirconia framework was customized to allow for subgingival porcelain space. This technique seems to contribute to the clinical-laboratory interface in computer-aided design/computer-assisted manufacture restorations.

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



    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.

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

    J. F. Wallace; D. Schwam


    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.

  17. Online industrial thermography of die casting tooling using dual-wavelength IR imaging

    Kourous, Helen E.; Shabestari, Behrouz N.; Luster, Spencer D.; Sacha, Jaroslaw P.


    Recent advances in IR system technology coupled with significant reduction sin cost are making thermography a viable tool for on-line monitoring of industrial processes. This paper describes the implementation of a novel rugged thermal imaging system based on a dual-wavelength technique for a large intelligent process monitoring project. The objective of the portion described herein is to deploy a non-contact means of monitoring die cast tooling surface thermal conditions and analyzing the data in the context of the process monitor. The technical and practical challenges of developing such a non-contact thermal measurement system for continuous inspection in an industrial environment are discussed, and methods of resolving them are presented. These challenges include implementation of a wavelength filter system for quantitative determination of the surface temperature. Additionally, emissivity variations of the tooling surface as well as IR reflections are discussed. The primary issues that are addressed, however, are compensation for ambient temperature conditions and optimization of the calibration process. Other issues center on remote camera control, image acquisition, data synchronization, and data interpretation. An example application of this system, along with in-plant images and thermal data, is described.

  18. Microstructural effects of phosphorus on pressure die cast Al-12Si components

    Suárez-Peña, B.


    Full Text Available The refinement of cuboidal silicon in eutectic Al-Si alloys by phosphorus additions used to manufacture pressure die cast components was studied. The results show that the addition of phosphorus in the form of AlFeP mother alloy before process degassing, leads to the best refinement of the size of the Si-cuboids phase, among several phosphorus additions analysed in the present research.

    Se ha estudiado el afino del silicio cuboidal en aleaciones eutécticas Al-Si por acción del fósforo, en piezas obtenidas mediante la técnica de fundición a presión. Tras la adición de fósforo en pruebas industriales, en las que dicho elemento se incorpora al baño con diversas composiciones, los mejores resultados se obtienen con la adición de la aleación madre AlFeP, previa al desgasificado industrial.

  19. Machining studies of die cast aluminum alloy-silicon carbide composites

    Sornakumar, Thambu; Kathiresan, Marimuthu


    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.

  20. Microstructure and property of zinc phosphate coating on die-casting magnesium alloy AZ91D

    LI Guang-yu; LIAN Jian-she; NIU Li-yuan; JIANG Zhong-hao


    A surface treatment method was described, which can form a uniform and dense phosphate conversion coating on the die -casting magnesium alloy AZ91D in a non-chromate and non-nitrite bath. The coating consists of Zn3(PO4)2-4H2O, Zn, AlPO4 and MgZn2(PO4)2 analyzed by XRD. The SEM results show that the microstructure of the zinc phosphate coating transfers from flower-like to slab-like crystals with the increase of immersion time of magnesium alloy samples in the phosphating bath. The zinc phosphate coating formed in the bath with immersion time of 1 min is denser because metallic Zn and insoluble phosphate crystals co-deposit on the magnesium alloy surface and the growth of the crystals are restricted by each others. The zinc phosphate coating on the magnesium alloy is used as the base layer for further cataphoric and powder paintings. The cataphoric painting on AZ91D alloy based on phosphate coating has similar adhesion and corrosion-resistance to that based on the chromate conversion coating. But for powder painting, the former exhibits better adhesion property than the latter, due to the uneven microstructure and the enough thickness of the phosphate coating.

  1. Galvanic corrosion behavior of die cast AZ91D magnesium alloy in chloride solution

    Zhensong Tong; Wei Zhang; Jiuqing Li; Jin Gao; Jiquan He; Ji Zhou


    The galvanic corrosion behavior of die cast AZ91D magnesium alloy coupled with H62 brass, 316L stainless steel, A3steel and LY12 aluminum alloy of different areas in 3.5% NaC1 solution was studied. The free corrosion potentials, galvanic potentials and currents of these galvanic couples were measured. The galvanic effects were determined by the mass loss and regression method using three points. The results show that: (1) In these four kinds of couples AZ91D acts as the anode, whose galvanic corrosion behavior is mainly controlled by the cathodic polarization; (2) The free corrosion potentials of these four kinds of couples change a liffle with time and cathodic/anodic area ratio (CAAR); (3) The galvanic potential of AZ91D/LY12 moves positively with the increase of time and CAAR; (4) The galvanic currents increase with CAAR, but there is difference in the current change between different couples; (5) The anodic dissolution rate of the magnesium alloy increases by 2-3 orders after being coupled with these four kinds of metals and the galvanic effects of these couples have such a relation as γH62>γ316LS.S>γLY12 >γA3.

  2. The fuzzy algorithm in the die casting mould for the application of multi-channel temperature control

    Sun, Jin-gen; Chen, Yi; Zhang, Jia-nan


    Mould manufacturing is one of the most basic elements in the production chain of China. The mould manufacturing technology has become an important symbol to measure the level of a country's manufacturing industry. The die-casting mould multichannel intelligent temperature control method is studied by cooling water circulation, which uses fuzzy control to realize, aiming at solving the shortcomings of slow speed and big energy consumption during the cooling process of current die-casting mould. At present, the traditional PID control method is used to control the temperature, but it is difficult to ensure the control precision. While , the fuzzy algorithm is used to realize precise control of mould temperature in cooling process. The design is simple, fast response, strong anti-interference ability and good robustness. Simulation results show that the control method is completely feasible, which has higher control precision.

  3. An establish attempt of reasons of machining splinter formation in AC47000 alloy high pressure die castings

    J. Mutwil


    Full Text Available A problem of splinter formation during machining the AC47000 alloy high pressure die casting has been experimental investigated. Inorder to establish the reason of this occurrence a set of 200 high pressure die casting of the tensile strength samples have been prepared. The tensile tests were carried out using a Zwick Z050 universal testing machine. JM-SPC program has been used for statistical analysis of test results. A large variability of tensile strength results has been found. In order to find the reason of this variability the fracture surfaceinvestigations (macrographs for all of samples and SEM micrographs for chosen samples have been carried out. It has been establish thatin all cases a significant decrease of tensile strength was caused by presence of inclusions or porosity.

  4. An establish attempt of reasons of machining splinter formation in AC44200 alloy high pressure die castings

    J. Mutwil


    Full Text Available A problem of splinter formation during machining the AC44200 alloy high pressure die casting has been experimental investigated. Inorder to establish the reason of this occurrence a set of 200 high pressure die casting of the tensile strength samples have been prepared. The tensile tests were carried out using a Zwick Z050 universal testing machine. JM-SPC program has been used for statistical analysis of test results. A large variability of tensile strength results has been found. In order to find the reason of this variability the fracture surface investigations (macrographs for all of samples and SEM micrographs for chosen samples have been carried out. It has been establish that in all cases a significant decrease of tensile strength was caused by presence of inclusions or porosity. In lot of cases the inclusions have a form of oxide film.

  5. Development of a new metal casting technique for micromechanical systems; Entwicklung einer neuen Metallgiesstechnik fuer die Mikromechanik

    Bach, F.W.; Moehwald, K.; Hollaender, U.; Nakhosteen, B. [Dortmund Univ. (Germany). Lehrstuhl fuer Werkstofftechnologie


    The effect that metallic molten masses can flow into deep and narrow gaps by capillary action forms the basis of the mould filling mechanism of the micro casting process presented here. Potential applications of ''Capillary Action Microcasting'' are the minimal invasive surgery (e. g. micromechanical endoscope items, grippers and cutting tools), magnetic actuators and the micro-electromechanical system (MEMS) technique (e. g. magnetic cores for micromechanical drive components and sensors) as well as the technology of mechanism design. Castings of a eutectic silver-copper alloy prove that both a definition and a guaranteed withdrawal of the cast part are achieved. The procedure is suitable and promising for the production of magnetic components, e. g. Fe47Sb53 for micro-electric motors. (orig.) [German] Der Effekt, dass metallische Schmelzen durch Kapillardruck in enge, tiefe Spalte einfliessen koennen, bildet die Basis fuer den Formfuellungsmechanismus des hier vorgestellten Mikro-Giessverfahrens, des ''Metall-Kapillardruckgiessens''. Potentielle Anwendungen werden in der minimalinvasiven Chirurgie (z. B. mikromechanische Endoskopelemente, Greiferzangen und Schneidwerkzeuge), der Magnetoaktorik und der mikro-elektromechanischen System (MEMS)-Technik, z. B. magnetische Kerne fuer mikromechanische Antriebselemente und Sensoren, sowie der Getriebetechnik erwartet. Abguesse, die mit Ag72Cu28-Schmelzen kapillardruckgegossen wurden, belegen, dass sowohl eine hohe Konturentreue als auch eine sichergestellte Entnahme des Gussteils realisiert wird. Das Verfahren ist geeignet und aussichtsreich fuer die Herstellung magnetischer Bauteile aus Fe47Sb53, wie z. B. fuer Mikro-Elektromotoren. (orig.)

  6. The impact of breaks during foundry work of the pressure casting machine on casting quality

    S. Borkowski


    Full Text Available The result in the appearance of the technical object damage are its failures, which are considered as the most important causes of productivity loss in the technical objects. The article introduces main types of losses resulting from the downtimes of a casting machine. The time impact analysis of the font mould failure and the remaining time of the machine's failures on the castings quality was conducted. The failure time structure of the font mould and other failures of the machine was presented.

  7. The Effect of Aluminum Content and Processing on the Tensile Behavior of High Pressure Die Cast Mg Alloys

    Deda, Erin M.

    Due to their high specific strength and good castability, magnesium alloys are desirable for use in weight reduction strategies in automotive applications. However, the mechanical properties of high pressure die cast (HPDC) magnesium can be highly variable and dependent on location in the casting. To better understand the relationship between microstructure and tensile properties, the influence of alloying and section thickness on the microstructural features and tensile properties of Mg-Al and Mg-Al-Mn alloys is quantified. This investigation provides experimental input to modeling activities for the development of an Integrated Computational Materials Engineering capability, to assess and quantify the impact of microstructure on the tensile behavior of HPDC Mg AM series (magnesium-aluminum-manganese) alloys. As a result of this work, it is found that with increasing aluminum content, the yield strength increases and the ductility decreases. Increasing the plate thickness results in a decrease in both the yield strength and ductility. HPDC components have varying microstructural features through the plate thickness, developing a "skin" and "core". The grain size, beta-Mg 17Al12 phase, and solute content are all quantified through the thickness of the plates. By quantifying microstructural variations, a physics-based model has been developed which is able to predict the effects of alloying and plate thickness on yield strength. The primary factors affecting strengthening are accounted for using a linear superposition model of solid solution, grain size, and dispersion hardening. This model takes into account through-thickness microstructure gradients that exist in HPDC components by using a composite model to incorporate the skin and core changes. The yield strength in these alloys is dominated by grain boundary strengthening and solute hardening effects. In order to isolate the effects of eutectic phases, shrinkage porosity and oxide films on strength and

  8. Mensuration and simulation of mold filling process in semi-solid die-cast of aluminum alloy

    YANG Yi-tao; WANG Jian-fu; ZHANG Heng-hua; SHAO Guang-jie


    To understand the flow trace of semi-solid slurry in mold cavity, some thermocouples were inserted in mold cavity, and the reaction timing of thermocouples showed the arrival of fluid. The filling time and rate were estimated by comparison between the experiment and calculation. The introduction of computer simulation technique based on ADSTEFAN was to predict injectionforming process and to prevent defects during trial manufacture of various parts. By comparing the formed appearance of parts in experiment and in simulation, and observing the relationship between internal defects inspected by X-ray or microscope and the flow field obtained in simulation, it was indicated that both have quite good agreement in simulation and experiment. Right predictions for cast defects resulted from mold filling can be carried out and proper direction was also proposed. The realization of numerical visualization for filling process during semi-solid die-cast process will play an important role in optimizing technology plan.

  9. Effect of Injection Velocity on Structure Part Characteristic in AZ50 Die Casting Process with High Vacuum System


    When diecasting large and thin Mg alloy parts, material defects occur, which include porosity, nonuniform mechanical properties, irregular surfaces, and incomplete filling. To resolve these problems, it is necessary to have uniform injection velocities and temperatures as well as control the melt. This study investigated the feasibility of producing large and thin components using a die caster by attaching a high vacuum system. In particular, the effects of injection velocity on surface quality and the mechanical properties of the products were investigated. Hence, an injection velocity scheme and a die structure capable of casting in a vacuum were proposed. As a result, it was found that the critical low injection velocity was 0.2 m/s to produce large thin Mg alloy structures having good mechanical properties.

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

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


    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.

  11. Structure and properties of Fe-Cr-Mo-C bulk metallic glasses obtained by die casting method

    W. Pilarczyk


    Full Text Available urpose: The goal of this work is to investigate structure and properties of Fe54Cr16Mo12C18 alloy rods with different diameters obtained by the pressure die casting method.Design/methodology/approach: Master alloy ingot with compositions of Fe54Cr16Mo12C18 was prepared by induction melting of pure Fe, Cr, Mo, C elements in argon atmosphere. The investigated material were cast in form of rods with different diameters. Glassy and crystalline structures were examined by X-ray diffraction. The microscopic observation of the fracture morphology was carried out by the SEM with different magnification. The thermal properties of the studied alloy were examined by DTA and DSC method.Findings: These materials exhibit high glass-forming ability, excellent mechanical properties and corrosion resistance.Research limitations/implications: It is difficult to obtain a metallic glass of Fe54Cr16Mo12C18 alloy. The investigations carried out on the different samples of Fe54Cr16Mo12C18 bulk metallic alloy allowed to state that the studied ribbon was amorphous whereas rods were amorphous – crystalline.Originality/value: The formation and investigation of the casted Fe-Cr-Mo-C bulk materials and the study of glass-forming ability of this alloy.

  12. Predicting Stress vs. Strain Behaviors of Thin-Walled High Pressure Die Cast Magnesium Alloy with Actual Pore Distribution

    Choi, Kyoo Sil; Barker, Erin; Cheng, Guang; Sun, Xin; Forsmark, Joy; Li, Mei


    In this paper, a three-dimensional (3D) microstructure-based finite element modeling method (i.e., extrinsic modeling method) is developed, which can be used in examining the effects of porosity on the ductility/fracture of Mg castings. For this purpose, AM60 Mg tensile samples were generated under high-pressure die-casting in a specially-designed mold. Before the tensile test, the samples were CT-scanned to obtain the pore distributions within the samples. 3D microstructure-based finite element models were then developed based on the obtained actual pore distributions of the gauge area. The input properties for the matrix material were determined by fitting the simulation result to the experimental result of a selected sample, and then used for all the other samples’ simulation. The results show that the ductility and fracture locations predicted from simulations agree well with the experimental results. This indicates that the developed 3D extrinsic modeling method may be used to examine the influence of various aspects of pore sizes/distributions as well as intrinsic properties (i.e., matrix properties) on the ductility/fracture of Mg castings.

  13. Theoretic and Experimental Studies on the Casting of Large Die-Type Parts Made of Lamellar Graphite Grey Pig Irons by Using the Technology of Polystyrene Moulds Casting from Two Sprue Cups

    Constantin Marta


    Full Text Available This paper presents a comparative analysis between the practical results of pig iron die-type part casting and the results reached by simulation. The insert was made of polystyrene, and the casting was downward vertical. As after the part casting and heat treatment cracks were observed in the part, it became necessary to locate and identify these fissures and to establish some measures for eliminating the casting defects and for locating them. The research method was the comparisons of defects identified through verifications, measurements, and metallographic analyses applied to the cast part with the results of some criteria specific to simulation after simulating the casting process. In order to verify the compatibility between reality and simulation, we then simulated the part casting respecting the real conditions in which it was cast. By visualising certain sections of the cast part during solidification, relevant details occur about the possible evolution of defects. The simulation software was AnyCasting, the measurements were done through nondestructive methods.

  14. Rapid die manufacturing - high pressure casting of low volume non ferrous metals components

    Pereira, MFV


    Full Text Available Pressure Casting of Low Volume Non Ferrous Metals Components Date: 2 November 2006 Slide 2 © CSIR 2006 Introduction to RPT • Rapid Prototyping Techniques (RPT) generally used for non functional prototypes • RPT...

  15. On the Structure Optimization and Design System Development of Die Casting Mould%压铸模具结构优选与设计系统开发



    介绍了压力铸造成形原理及其工艺过程、剖析了压力铸造成形工艺的优点和存在的缺陷;总结了压力铸造技术的发展历史、应用范围及中国压力铸造生产产品应用领域的多元性,展示了中国压力铸造业发展的广阔前景。%This paper introduces the principle and forming process of the pressure casting and analyzes the advantages and disadvantages of pressure casting forming technology. It summarizes the development history and application range of the pressure casting technology and Chinese pressure casting product diversity,and shows the prospect of the development of Chinese die casting industry.

  16. Microstructural stability of heat-resistant high-pressure die-cast Mg-4Al-4Ce alloy

    Wang, Wei; Zhang, Jinghuai; Li, Guoqiang; Feng, Yan; Su, Minliang; Wu, Ruizhi; Zhang, Zhongwu [Harbin Engineering Univ. (China). Key Laboratory of Superlight Material and Surface Technology; Jiao, Yufeng [Jiamusi Univ. (China). College of Materials Science and Engineering


    The thermal stability of Al-RE (rare earth) intermetallic phases with individual RE for heat-resistant high-pressure die-casting Mg-Al-RE alloys is investigated. The results of this study show that the main strengthening phase of Mg-4Al-4Ce alloy is Al{sub 11}Ce{sub 3}, whose content is about 5 wt.% according to quantitative X-ray diffraction phase analysis. The Al{sub 11}Ce{sub 3} phase appears to have high thermal stability at 200 C and 300 C, while phase morphology change with no phase structure transition could occur for Al{sub 11}Ce{sub 3} when the temperature reaches 400 C. Furthermore, besides the kinds of rare earths and temperature, stress is also an influencing factor in the microstructural stability of Mg-4Al-4Ce alloy.

  17. Self-sealing anodization approach to enhance micro-Vickers hardness and corrosion protection of a die cast Al alloy

    Lee, Chulho; Oh, Kiseok; Lee, Dongeun; Kim, Yelim; Yoon, Hyungsop; Park, Dong-Wha; Gab Kim, Moon; Lee, Kiyoung; Choi, Jinsub


    Die cast, high-Si content ADC12 Al alloy samples were successfully anodized without surface cracks. This was accomplished with a 0.3 M sulfuric acid electrolyte with a high concentration of sodium aluminate. During anodization, the AlO2- anions were attracted to the positively-charged Al substrate and deposited in the cracks formed by un-oxidized Si islands within the ADC12. Anodic films prepared in electrolytes with a high concentration of AlO2- drastically enhanced surface morphology, thickness uniformity, Vickers hardness, and corrosion behavior in comparison with anodic film prepared without AlO2- concentration. The simultaneous sealing mechanism by AlO2- anions during anodization is reported in detail.

  18. An improved mathematical model to simulate mold filling process in high pressure die casting using CLSVOF method and CSF model

    Cheng Bi


    Full Text Available A 3D mathematical model was proposed to simulate the mold filling process in high-pressure die casting (HPDC to improve accuracy considering the surface tension. Piecewise liner interface calculation (PLIC and volume of fluid (VOF methods were used to construct the pattern of the liquid interface. A coupled level-set and VOF method (CLSVOF was proposed to capture the interface pattern and obtain its normal vector. A continuum surface force (CSF model was used to consider the surface tension. Two water analogy experiments were carried out using the proposed model. Simulation and experimental results were analyzed and compared; and the effects of surface tension were also discussed. The simulation results agreed well with the experiments and the simulation accuracy was an improvement on interface geometries, liquid flows, and gas entrapments.

  19. Fabrication of ZnO Nanowires Arrays by Anodization and High-Vacuum Die Casting Technique, and Their Piezoelectric Properties.

    Kuo, Chin-Guo; Chang, Ho; Wang, Jian-Hao


    In this investigation, anodic aluminum oxide (AAO) with arrayed and regularly arranged nanopores is used as a template in the high-vacuum die casting of molten zinc metal (Zn) into the nanopores. The proposed technique yields arrayed Zn nanowires with an aspect ratio of over 600. After annealing, arrayed zinc oxide (ZnO) nanowires are obtained. Varying the anodizing time yields AAO templates with thicknesses of approximately 50 μm, 60 μm, and 70 μm that can be used in the fabrication of nanowires of three lengths with high aspect ratios. Experimental results reveal that a longer nanowire generates a greater measured piezoelectric current. The ZnO nanowires that are fabricated using an alumina template are anodized for 7 h and produce higher piezoelectric current of up to 69 pA.

  20. Fabrication of ZnO Nanowires Arrays by Anodization and High-Vacuum Die Casting Technique, and Their Piezoelectric Properties

    Chin-Guo Kuo


    Full Text Available In this investigation, anodic aluminum oxide (AAO with arrayed and regularly arranged nanopores is used as a template in the high-vacuum die casting of molten zinc metal (Zn into the nanopores. The proposed technique yields arrayed Zn nanowires with an aspect ratio of over 600. After annealing, arrayed zinc oxide (ZnO nanowires are obtained. Varying the anodizing time yields AAO templates with thicknesses of approximately 50 μm, 60 μm, and 70 μm that can be used in the fabrication of nanowires of three lengths with high aspect ratios. Experimental results reveal that a longer nanowire generates a greater measured piezoelectric current. The ZnO nanowires that are fabricated using an alumina template are anodized for 7 h and produce higher piezoelectric current of up to 69 pA.

  1. Die-cast heterophase composites with AlSi13Mg1CuNi matrix

    M. Dyzia


    Full Text Available On the basis of the performed tests, an advantageous interaction of glassy carbon particles in a couple consisting of a heterophase composite and a spheroidal cast iron has been corroborated. It was found that, the presence of glassy carbon in the heterophase composite (SiC+C affects the stabilization of the friction coefficient value as a function of the friction distance and reduces the intensity of the wearing-in stage of the interacting surfaces. Both a decrease of the friction coefficient and the wear of the heterophase composites may be connected with the carbon particles' chipping effect and the deposition of its fragments on the surface of the interacting components of the friction couple, which forms a kind of a solid lubricating agent in the system. This should allow applying of this material to the composite piston - cylinder sleeve system in piston air-compressors. Further works will concern the selection of the matrix alloy composition with the purpose of reducing the phenomenon of particles chipping during machining. It seems that one of the possibilities is the application of a more plastic matrix and optimizing the fraction of reinforcing phases and their gradient distribution in the casting.

  2. Elasto-Plastic-Creep Constitutive Equation of an Al-Si-Cu High-Pressure Die Casting Alloy for Thermal Stress Analysis

    Motoyama, Yuichi; Shiga, Hidetoshi; Sato, Takeshi; Kambe, Hiroshi; Yoshida, Makoto


    Accurate simulation of residual stress and deformation is necessary to optimize the design and lifetime of casting components. Therefore, the recovery and strain-rate dependence of the stress-strain curve have been incorporated into empirical constitutive equations to improve the thermal stress analysis accuracy. Nevertheless, these equations present several difficulties related to the determination of material constants and their physical bases. This study suggested an empirical elasto-plastic-creep constitutive equation incorporating these phenomena. To determine the material parameters used in this constitutive equation, this study investigated tensile test methods to obtain stress-strain curves that most closely resemble those during or immediately after casting for the Al-Si-Cu high-pressure die-casting alloy JIS ADC 12 (A383.0), which exhibits natural aging. Results show that solution heat treatment with subsequent cooling to the test temperature should be applied to obtain stress-strain curves used for the thermal stress analysis of high-pressure die casting process of this alloy. The yield stresses obtained using the conventional heating method were 50-64 pct higher than those of the method described above. Therefore, the conventional method is expected to overestimate the overestimation of the predicted residual stress in die castings. Evaluation of the developed equation revealed that it can represent alloy recovery and strain-rate dependence.

  3. The effect of natural pre-ageing on the mechanical properties of Rheo-High pressure die cast aluminium alloy 2139

    Chauke, L


    Full Text Available -high pressure die casting process (R-HPDC). Alloy 2139 is a Ag-containing aluminium alloy from the Al-Cu-Mg 2xxx series family. The addition of Ag enhances the age hardening response through the formation of co-clusters that act as precursors to the formation...

  4. Technological Superiority and Application of Real-Time Control Die Casting Machine%实时控制压铸机的技术优势及应用*

    张新华; 孔晓武


    This article introduces the development of die casting machine controlling theory, concept and feature of die casting machine embedded real time operating system,with drawing conclusions that contain electro-hydraulic schematic diagram for die casting machine injection system, configuration scheme of embedded real time controlling, analysis of real time control curve and comparison with traditional controlling technique. The real time control die casting machine which referred in this article has been to the stage of application,and won quite considerable market share and high praise.%介绍了压铸机控制理论的发展和压铸机嵌入式实时控制技术的概念及其特点优势,给出了压铸机压射系统的电液原理图,嵌入式实时控制的配置方案,实时控制曲线的分析及与传统控制技术的对比。介绍的实时控制压铸机已经进入应用环节,并取得了较大的市场份额和较好的评价。

  5. The Influence of Pressure Die Casting Parameters on Distribution of Reinforcing Particles in the AlSi11/10% SiC Composite

    A. Pasieka


    Full Text Available The method of pressure die casting of composites with AlSi11 alloy matrix reinforced with 10 vol. % of SiC particles and the analysis of the distribution of particles within the matrix is presented. The composite castings were produced at various values of the piston velocity in the second stage of injection, at diverse intensification pressure values, and various injection gate width values. The distribution of particles over the entire cross-section of the tensile specimen is shown. The index of distribution was determined on the basis of particle count in elementary measuring fields. The regression equation describing the change of the considered index was found as a function of the pressure die casting parameters. The conclusion presents an analysis of the obtained results and their interpretation.

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

    K. M. McHugh; B. R. Wickham


    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.

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

    Mc Hugh, Kevin Matthew


    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.

  8. Solidification and casting

    Cantor, Brian


    INDUSTRIAL PERSPECTIVEDirect chillcasting of aluminium alloysContinuous casting of aluminium alloysContinuous casting of steelsCastings in the automotive industryCast aluminium-silicon piston alloysMODELLING AND SIMULATIONModelling direct chill castingMold filling simulation of die castingThe ten casting rulesGrain selection in single crystal superalloy castingsDefects in aluminium shape castingPattern formation during solidificationPeritectic solidificationSTRUCTURE AND DEFECTSHetergeneous nucleation in aluminium alloysCo

  9. The effect of microstructure of low-alloy spheroidal cast iron on impact strength

    T. Szykowny


    Full Text Available The study presents an evaluation of the effect of microstructure of low-alloy spheroidal cast iron on impact strength within the temperature range from –60 to 100°C. Analyses were conducted on one type of cast iron containing 0.51% Cu and 0.72% Ni. Cast iron was austempered or normalized. Values of KCV and static mechanical properties were determined. Structural and fractographic analyses were based on light and scanning microscopy as well as X-ray diffraction. It was found that thermal processing considerably improves impact strength in relation to cast iron after casting. At the same time static mechanical properties are enhanced.

  10. Discussion on Reducing Costs of Die-Cast Automotive Starter-Generator Cover Die Casting%压铸汽车起动机-发电机端盖压铸件降本初探



    主要介绍了铝压铸件企业通过对原材料牌号进行分类和归纳,在对比了原材料的力学性能和化学成分,得出具有通用性的材料牌号,将3种材料牌号统一成一个牌号,实现单一牌号的采购和生产。在确保产品质量的前提下,降低原材料的采购成本、生产成本和管理成本,最终实现了产品成本降低的目标。%The aluminum die casting enterprises through classification and induction of raw material grades, and by comparing the mechanical properties and chemical composition of raw materials, obtained the universal material grades, three kinds of material grades have been uniifed into a single grade, so that a single brand of procurement and production has been achieved. In the premise of ensuring the quality of products, the raw materials procurement costs, production costs and management costs have been achieved, finally the product cost reduction target has been realized.

  11. Pressing Speed, Specific Pressure and Mechanical Properties of Aluminium Cast

    Gaspar S.


    Full Text Available Recent research in the process of aluminum alloy die castings production, which is nowadays deeply implemented into the rapidly growing automobile, shipping and aircraft industries, is aimed at increasing the useful qualitative properties of the die casting in order to obtain its high mechanical properties at acceptable economic cost. Problem of technological factors of high pressure die casting has been a subject of worldwide research (EU, US, Japan, etc.. The final performance properties of die castings are subjected to a large number of technological factors. The main technological factors of high pressure die casting are as follows: plunger pressing speed, specific (increase pressure, mold temperature as well as alloy temperature. The contribution discusses the impact of the plunger pressing speed and specific (increase pressure on the mechanical properties of the casting aluminum alloy.

  12. Microstructure, Impact Fatigue Resistance and Impact Wear Resistance of Wear Resistant Low Cr-Si Cast Iron


    A great amount of iron and steel has been consumed in impact wear resistance parts such as grinding balls and lining plates in tube mills. Under this working conditions, the failure of wear resistant white irons is generally caused by fatigue spalling. The martensitic high chromium cast iron (WCr=15 %) has good wear resistance, but its cost is higher. The impact wear resistance of low chromium cast iron sometimes is not good. In the present paper ,a new wear resistant material-low Cr-Si cast iron was introduced. The influence of microstructure of cast iron on impact fatigue resistance and impact wear resistance was discussed. The ball-on-ball impact fatigue test, the high stress impact wear test and the field test of the grinding balls have been carried out. The results showed that the impact fatigue resistance (IFR) and impact wear resistance (IWR) of low Cr-Si cast iron are superior to typical low chromium cast irons and close to the martensitic high chromium cast iron. The main reasons are: ① The as-cast matrix of the low Cr-Si cast iron with stress released is pearlite with better plasticity and toughness; ② The high Si content improves the morphology of eutectic carbide, and has no secondary carbide resulting in less crack sources. All these factors are beneficial to the improvement of impact fatigue spalling resistance and impact wear resistance.

  13. An eco design strategy for high pressure die casting components: microstructural analysis applied to mass reducing processes; Una estrategia de ecodiseno de piezas obtenidas mediante moldeo a presion: analisis microestructrual aplicado a la desmaterializacion

    Suarez-Pena, B.; Asensio-Lozano, J.


    In this work the study focused on the possibility of use of new aluminium alloys with optimized microstructures that ensure the mechanical properties requested for cast components made by high pressure die casting. The objective was to check the possibility of manufacture of structurally sound eco-steps for escalators with reduced structural integrity. The former arises as a result of a new redesign of the traditional steps aiming at a significant weight reduction. The experimental results show that it is feasible to cut the use of materials during processing and therefore to reduce the impact of the components during its lifetime, whilst the performance and safety standards are kept identical or even improved. (Author) 17 refs.

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


    The effect of addition of different concentrations of Ce on high-cycle fatigue behavior of die-cast magnesium al-loy AZ91D was investigated. Mechanical fatigue tests were conducted at the stress ratio of R = 0.1, and fatigue strength was evaluated using up-and-down loading method. The results show that the grain size of AZ91D alloy is remarkably refined, and the amount of porosity decreases and evenly distributes with the addition of Ce. The fatigue strength of AZ91D alloy at room temperature increases from 96.7 up to 116.3 MPa (1% Ce) and 105.5 MPa (2% Ce), respectively, at the number of cycles to failure, Nf = 1 × 107. The fatigue crack of AZ91D alloy initiates at porosities and inclusions, and propagates along grain boundaries. The fatigue striations on fractured surface appear with Ce addition. The fatigue fracture surface of test specimens shows mixed-fracture characteristics of quasi-cleavage and dimple.

  15. Vacuum Die Casting Process and Simulation for Manufacturing 0.8 mm-Thick Aluminum Plate with Four Maze Shapes

    Chul Kyu Jin


    Full Text Available Using vacuum die casting, 0.8 mm-thick plates in complicated shapes are manufactured with the highly castable aluminum alloy Silafont-36 (AlSi9MgMn. The sizes and shapes of the cavities, made of thin plates, feature four different mazes. To investigate formability and mechanical properties by shot condition, a total of six parameters (melt temperatures of 730 °C and 710 °C; plunger speeds of 3.0 m/s and 2.5 m/s; vacuum pressure of 250 mbar and no vacuum are varied in experiments, and corresponding simulations are performed. Simulation results obtained through MAGMA software show similar tendencies to those of the experiments. When the melt pouring temperature is set to 730 °C rather than 710 °C, formability and mechanical properties are superior, and when the plunger speed is set to 3.0 m/s rather than to 2.5 m/s, a fine, even structure is obtained with better mechanical properties. The non-vacuumed sample is half unfilled. The tensile strength and elongation of the sample fabricated under a melt temperature of 730 °C, plunger speed of 3.0 m/s, and vacuum pressure of 250 mbar are 265 MPa and 8.5%, respectively.

  16. Life cycle assessment as a method of limitation of a negative environment impact of castings

    M. Holtzer


    Full Text Available Casting production constitutes environmental problems going far beyond the foundry plant area. Applying a notion of the life cycle the input (suppliers side and output factors (clients side can be identified. The foundry plant activities for the environment hazard mitigation can be situated on various stages of the casting life cycle. The environment impact of motorisation castings made of different materials – during the whole life cycle of castings – are discussed in the paper. It starts from the charge material production, then follows via the casting process, car assembly, car exploitation and ends at the car breaking up for scrap.

  17. Effect of T4 and T6 treatment on corrosion of die cast AZ91D magnesium alloys in 3.5% NaCl

    ZHOU Wan-qiu; SHAN Da-yong; HAN En-hou; KE Wei


    The effect of heat treatment on microstructure and corrosion behavior of die-cast AZ91D magnesium alloys in 3.5% NaCl solution was investigated by SEM, EDX, XRD and electrochemical technique. It is found that the distribution of β phase influences the corrosion morphology. Corrosion occurs preferentially in primary α phase and presents pitting corrosion feature in die-cast AZ91D. After homogenization of T4 treatment, β phase dissolves in α phase and forms a single phase with α matrix, and the corrosion form turns to localized corrosion. The attack initiates at local site, expands towards deep direction and produces "digging effect". After artificial aging of T6 treatment, β phase is produced in abundance and provides a great deal of effective micro-cathode for anodic dissolution, and the corrosion form exhibits in general corrosion.

  18. J1140型压铸机增压蓄能器设计%Design of Booster Accumulator for J1140 Type Die Casting Machine



    According to the design requirements of injection system of J1140 type die casting machine,the hydraulic principle of die casting machine injection system booster was analyzed,the volume of the accumulator was calculated. Combining with practical ap-plication,the choice and application methods of accumulator was introduced.%根据J1140型压铸机压射系统的设计要求,分析压铸机压射系统增压液压原理,对增压蓄能器的容积进行计算;结合实践应用,介绍蓄能器的选择及应用方法。

  19. Effects of Dy, Sr and Die Casting on Microstructure, Mechanical and Corrosion Properties of Mg-Dy-Sr-Nd-Zr Alloys

    Liu, Dexue; Yin, Xunyan; Pang, Xin; Hu, Shiwen; Ding, Yutian


    By adding 2, 6 and 10 wt.% Dy and 0.5, 1.5 and 2 wt.% Sr elements to Mg-2.4Nd-0.5Zr alloys and adopting die-casting process for biomedical Mg-10Dy-0.5Sr-2.4Nd-0.5Zr alloys, the effects of Dy and Sr elements and die-casting process on the microstructure, mechanical properties and corrosion resistance of Mg-Dy-Sr-Nd-Zr alloys were investigated. The new biomedical Mg-10Dy-0.5Sr-2.4Nd-0.5Zr alloys were designed, and the grain size of the as-cast new alloy was refined to 70 μm and distributed equably. The ultimate tensile strength increased with increasing Dy content and decreasing Sr content. The corrosion rate decreased firstly and then increased with increasing Dy content and decreased with increasing Sr content. By adjusting the content of Sr and Dy, the ultimate tensile strength of as-cast new Mg-10Dy-0.5Sr-2.4Nd-0.5Zr alloys increased to 203 MPa, elongation was 7.4%, and the corrosion rate decreased to 0.48 mm/a. The elongation rate increased to 10.2% after the new biomedical alloys were processed by die casting with an refine-grained microstructure of 18 μm, meanwhile the ultimate tensile strength decreased to 180 MPa, and the corrosion rate was 1.29 mm/a.

  20. A new approach to assess the effects of Sr and Bi interaction in ADC12 Al–Si die casting alloy

    Farahany, Saeed, E-mail:; Ourdjini, Ali; Abu Bakar, Tuty Asma; Idris, Mohd Hasbullah


    Highlights: • Interactive effect between Bi and Sr has been invesitigated comprehensively. • Sequence of addition did not affect thermal and microscopical characteristics. • A new map has been established to assess the final microstructure of castings. - Abstract: In the present paper, the possible interaction between bismuth and strontium in ADC12 die casting alloy was investigated comprehensively by using in situ thermal analysis technique. The characteristic temperatures including nucleation, minimum and growth temperatures of eutectic Al–Si were also analyzed. The results show that with Bi present in the Al–Si alloy melt the efficiency of Sr in modifying the eutectic Si is reduced. A threshold Sr/Bi ratio of at least 0.5 is required for a fully modified Si structure to form. A new map based on the characteristic temperatures, Sr/Bi ratio and microstructure, was established to assess the microstructure of fully solidified Al–Si castings.

  1. Die-casting Process for High-performance Thin-wall Casting of Aluminum Alloy%高性能薄壁铝合金铸件的压铸

    尹志鹏; 宋朝辉; 李义平


    采用本公司发明的专利技术制备了铝合金浆料。概述了高性能薄壁多抽芯铝合金铸件的半固态流变压铸生产过程。经半固态流变压铸生产的铝合金铸件的显微组织致密,无气孔、缩松和夹杂,T6热处理后的力学性能比普通压铸件提高了40%左右。%Aluminum alloy paste was fabricated with a patent technology invented by Cixi Alt Advanced Materials Co.. The semi-solid rheocasting process for high-performance multi-core thin-wall aluminum alloy castings was outlined. The aluminum alloy castings produced by the semi-solid rheologic die-casting technology exhibited dense structure in which there are not any pore, porosity and inclusion, and after being T6 treated its mechanical properties were 40% higher that of common die castings.

  2. Impact Toughness and Heat Treatment for Cast Aluminum

    Lee, Jonathan A (Inventor)


    A method for transforming a cast component made of modified aluminum alloy by increasing the impact toughness coefficient using minimal heat and energy. The aluminum alloy is modified to contain 0.55%-0.60% magnesium, 0.10%-0.15% titanium or zirconium, less than 0.07% iron, a silicon-tomagnesium product ratio of 4.0, and less than 0.15% total impurities. The shortened heat treatment requires an initial heating at 1,000deg F. for up to I hour followed by a water quench and a second heating at 350deg F. to 390deg F. for up to I hour. An optional short bake paint cycle or powder coating process further increase.

  3. Safety-relevant components made of low-iron, Al-base die-casting alloys; Sicherheitsbauteile aus eisenarmen Aluminium-Druckgusslegierungen

    Hielscher, U. [Aluminium Rheinfelden GmbH, Rheinfelden (Germany)


    The modern automotive engineering requirements to be met by die-casting aluminium alloys with respect to the microstructure, casting process, compatibility with operating media, and weldability are such that they cannot be met by conventional alloys. Therefore, there was a quest for novel alloys, which at the Aluminium Rheinfelden company has led to the development of two low-iron alloys: Silafont-36 (AlSi9MgMnSr), and Magsimal-59 (AlMg5Si2Mn). The materials properties and some applications are explained. (orig./MM) [German] Von der Automobilindustrie werden an die Aluminiumguss-Legierungen folgende Anforderungen gestellt: 1. sehr duktiles Gefuege, 2. gute Giessbarkeit fuer das Druckgiessverfahren, 3. Vertraeglichkeit mit den Eisenwerkstoffen der Giesswerkzeuge sowie Trenn- und Schmierstoffen, 4. gute Schweissbarkeit und gute Boerdelbarkeit. Die herkoemmlichen Gusslegierungen erfuellen diese Anforderungen nicht; der Aluminium Rheinfelden gelang die Entwicklung von zwei eisenarmen Legierungen: Silafont-36 (AlSi9MgMnSr) und Magsimal-59 (AlMg5Si2Mn). (orig.)

  4. Low temperature impact strength of heavy section ductile iron castings: effects of microstructure and chemical composition

    C. Labrecque


    Full Text Available A foundry research project has been recently initiated at RTIT in order to better understand the fabrication of as-cast heavy section DI parts meeting high impact energy requirements at low temperatures. The experimental castings have the following dimensions 180 mm x 180 mm x 190 mm. The achieved as-cast Charpy impact strengths were as follows: 17 J (RT, 16 J (-20°C and 11 J (-40°C. The foundry process, the chemical composition and the microstructure of this experimental casting are compared to the ones of various examples in order to show the detrimental effects of residual elements, microshrinkage and microcarbide on the impact properties. Finally, quality index empirical models (based on casting chemical compositions are used to analyse the impact tests results. This paper illustrates that an adequate nodule count can contribute to reducing the detrimental effects of the residual elements and microsegregation.

  5. 压铸镁合金汽车方向盘骨架的工艺研究%Research Die Casting Magnesium Alloy Steering Wheel Skeleton

    安帅杰; 王峰


    FLOW-3D simulation software for die-casting process car steering wheel skeleton is designed and optimized to determine the optimum casting process parameters;using optical microscopy,scanning electron microscopy analysis of the organizational structure of the steering wheel skeleton.Determine the best framework for the die casting process parameters by orthogonal experiment method:pouring temperature 700℃,die-type temperature 220℃,injection speed 2.34m/s.Under this argument,casting good shape, and actual results and simulation results are basically consistent.Skeleton dense,with good ductility.%利用FLOW-3D模拟软件对汽车方向盘骨架的压铸工艺进行了设计与优化,确定了较优的压铸工艺参数;利用金相显微镜、扫描电镜分析了方向盘骨架的组织结构。采用正交实验法确定骨架最佳的压铸工艺参数:浇注温度700℃、压铸型温度220℃、压射速度2.34m/s。在此工艺参数下,压铸件成型良好,实际结果与模拟结果基本吻合。骨架组织致密,具有良好的塑性。

  6. Zinc Base Die Castings


    183 B86- 33T SAE N.J .zn Co. B86-33T 1934 SAE N.J.Zn Cc,. Zamak 3N AllO;E Cl C2 Allo~ XXI 221 Zarnak 2 .A.llo;z XXIII .Allol XXIII 202 Zamak 2 O...2 Pb ,Fe, Cd, C:’. 3 special high gra1e ?:inc. • t • • ; -J TABLE II Chemical Composition for Zinc Alloy Nuuber Zam.ak 2 Zamak 3...was alco given regarding the aging of the alloys. The a1loy3 Aupplied were: Zamak 2, Zamak 3, Zamak 3-S (Stabilized to hasten contraction which

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

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


    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 β-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 β-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.

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

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


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

  9. Effect of Microstructure on Impact Fatigue Resistance and Impact Wear Resistance of Medium Cr-Si Cast Iron

    LI Wei


    A great amount of iron grinding balls in tube mills have been consumed. Under this impact abrasive wear working condition, the failure of wear resistant alloying white irons grinding balls is mainly caused by fatigue spalling. The impact wear resistance of martensitic high chromium cast iron (Cr of 15 %) is not high sometimes, but its cost is not low. Thus, medium Cr-Si wear resistant cast iron is recommended. The influence of the iron on impact fatigue resistance and impact wear resistance is pronounced. Ball-on-ball impact fatigue test and high stress impact wear test of the grinding balls have been carried out. The results show that the impact fatigue resistance (IFR) and impact wear resistance (IWR) of medium Cr-Si cast iron are superior to those of martensitic high chromium cast iron (Cr of 15%). The main reasons are that (1) the stress in medium Cr-Si cast iron is released in the as-cast state; (2)the matrix is fine pearlite with better toughness and plasticity; (3) the pearlite is more stable compared with a retained austenite under repeated impact load and less phase transformation can take place; (4) high silicon content improves the morphology of eutectic carbide; (5) there is no secondary carbide which results in less crack sources. All these factors are beneficial to improvement of impact fatigue spalling resistance. The eutectic carbide M7C3 is the main constituent to resist wear.

  10. The Effect of Water Mist Cooling of Casting Die on the Solidification, Microstructure and Properties of AlSi20 Alloy

    Władysiak R.


    Full Text Available Unmodified AlSi20 alloy were casted at the research station, allowing for sequential multipoint cooling using a dedicated computer- controlled program. This method allows for the formation of the microstructure of hypereutectic AlSi20 alloy and also increases hardness. Primary silicon dendrites were found in the microstructure of cooled samples. Based on these dendrites, the formation of primary silicon particles is explained. Cooling of casting die with a water mist stream causes changes in solidification, which leads to expansion of the boundary layer with columnar crystals and shrinkage of the core zone with equiaxed crystals. It also causes more regular hardness distribution around pre-eutectic Si crystals, which can lead to tensile strength and machinability improvement.

  11. CAE模拟分析在水龙头手柄压铸模设计中的应用%Application of CAE Simulation Analysis to the Design of Die Casting Mold for Faucet Handle



    针对传统压铸模具浇注系统设计采用试错法存在的缺陷,本文通过水龙头手柄压铸模设计,提出利用ProCAST铸造模拟分析功能,先确定内浇道合理位置,再进行浇注系统详细设计及模具设计,避免浇注系统对铸件成形过程不利影响,提高铸件质量,缩短模具制造周期.可为类似铸件浇注系统及压铸模具设计提供参考.%Aimed at the existing defects of traditional die casting mold gating system design by trial-and-error method, first the reasonable location of the ingate was determined and then the gating system and mold were designed in detail through designing the faucet handle die-casting mold, utilizing ProCAST casting simulation analysis capabilities, which avoid the adverse effects of the gating system for casting formation process, improve casting quality, and reduce mold manufacturing period. It can provide a reference for similar casting gating system and die casting mold design.

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

    Chun, Sung-Yong


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

  13. Microstructural and mechanical properties of gravity-die-cast A356 alloy inoculated with yttrium and Al-Ti-B grain refiner simultaneously

    Y.P. Lim


    Full Text Available In the present work, the effect of inoculating yttrium and Al-5Ti-1B simultaneously on A356 aluminum alloy has been studied. Gravity die casting process is used to cast the ASTM tensile test specimens for analysis. In each experiment, the Ti and B contents were maintained constantly at 0.1 and 0.02 wt% respectively. The addition of yttrium was manipulated at the amount of 0, 0.1, 0.2, 0.3, 0.4 and 0.5 wt%. Microstructural characterization of the as-cast A356 alloy was investigated by means of optical microscope and its phases are detected by XRD. The mechanical properties tested are tensile strength and hardness. The inoculation of yttrium was found to enhance the grain refinement effect of Al-5Ti-1B grain refiner and improve the mechanical properties. The optimal weight percentage of yttrium was found to be 0.3. The grain refining efficiency of combining yttrium and Al-5Ti-1B on A356 aluminum alloy was mainly attributed to the heterogeneous nucleation of TiB2 and TiAl3 particles which were dispersed more evenly in the presence of yttrium and the grain growth restriction effected by the accumulation of Al-Y compound at grain boundaries.

  14. Microstructure, Mechanical and Surface Morphological Properties of Al5Ti5Cr Master Alloy as Friction Material Prepared by Stir Die Casting

    Ahmed, Syed Faisal; Srivastava, Sanjay; Agarwal, Alka Bani


    Metal matrix composite offers outstanding properties for better performance of disc brakes. In the present study, the composite of AlTiCr master alloy was prepared by stir die casting method. The developed material was reinforced with (0-10 wt%) silicon carbide (SiC) and boron carbide (B4C). The effects of SiC reinforcement from 0 to 10 wt% on mechanical, microstructure and surface morphological properties of Al MMC was investigated and compared with B4C reinforcement. Physical properties like density and micro Vickers hardness number show an increasing trend with an increase in the percentage of SiC and B4C reinforcement. Mechanical properties viz. UTS, yield strength and percentage of elongation are improved with increasing the fraction of reinforcement. The surface morphology and phase were identified from scanning electron microscopy (SEM) and X-ray diffraction analysis and the oxidized product formed during the casting was investigated by Fourier transformation infrared spectroscopy. This confirms the presence of crystallization of corundum (α-Al2O3) in small traces as one of the alumina phases, within casting sample. Micro-structural characterization by SEM depicted that the particles tend to be more agglomerated more and more with the percentage of the reinforcement. The AFM results reveal that the surface roughness value shows a decreasing trend with SiC reinforcement while roughness increases with increase the percentage of B4C.

  15. 77 FR 6587 - PHB Die Casting a Subsidiary of PHB, Inc., Including On-Site Leased Workers From Career Concepts...


    ... Workers From Career Concepts and Volt Services, Including a Contract Worker From Burns Industrial Group... subsidiary of PHB, Inc., including on-site leased workers from Career Concepts and Volt Services, Fairview... Casting, a subsidiary of PHB, Inc., Fairview, Pennsylvania, including on-site leased workers from...

  16. Unnotched Charpy Impact Energy Transition Behavior of Austempered Engineering Grade Ductile Iron Castings

    Kisakurek, Sukru Ergin; Ozel, Ahmet


    Unnotched Charpy impact energy transition behavior of five different engineering grade ductile iron castings, as specified by EN 1563 Standards, were examined in as-cast, as well as in austempered states. ADIs were produced with the maximum impact energy values permissible for the grades. Austempering treatment detrimented the sub-zero impact properties of the ferritic castings, but considerably enhanced those of the pearlitic-ferritic irons. The impact energy transition behavior of the austempered states of all the grades examined were noted to be determined by the progressive transformation of the unavoidable carbon-unsaturated and untransformed regions of the austenite remaining in the matrix of the austempered ductile iron to martensite with decreasing temperature.

  17. Die-cast of a hypo-eutectic AL-SI alloy: influence of injection temperature on microstructure and mechanical properties; Fundicao sob pressao das ligas de AL-SI: influencia da temperatura de injecao nas microestruturas e propriedades mecanicas

    Santos, Silvano Leal dos; Santos, Sydney Ferreira, E-mail: [Universidade Federal do ABC (UFABC), SP (Brazil)


    Die-casting is widely used for manufacturing light alloy components for automotive industry. Among others, hypo-eutectic Al-Si alloys are currently processed by die-casting. To obtain high quality die-cast components, a better understanding on the correlations between processing parameters, microstructures, and mechanical properties are of utmost importance. In this study, we investigate the effect of injection temperature of liquid metal on the microstructure and mechanical properties of Al-Si alloy EN AC 46000 (DIN designation). The injection temperatures were 579, 589, 643, and 709 deg C. As-cast components had their microstructures analyzed by X-ray diffraction, optical and scanning electron microscopy, and X-ray energy dispersive spectroscopy. The mechanical properties were examined by micro-hardness and tensile tests. It was observed that the ultimate tensile strength slightly increased with the increase of injection temperature. The same trend was observed for micro-hardness. The amount of porosity in the samples varies in a small amount for different injection temperatures. On the other hand, the microstructure of the alloys seems more refined for higher temperatures of injection. This refinement in microstructure might play a major role on the mechanical properties of the Al-Si die-cast alloy. (author)

  18. Effect of post-welding heat treatment on wear resistance of cast-steel die with surfacing layer

    Xu Wujiao


    Full Text Available The wear resistance capability of die surfacing layer under different Post-Welding Heat Treatments (PWHT was analysed by Finite Element (FE simulation and experiments. Taking hot forging process of a crankshaft as an example, a wear model of the hot forging die coated with surfacing layer was established using FE software DEFORM-3D. The simulation results indicated that the wear resistance capability of the die surfacing layer is optimal when tempering temperature and holding time are 550 °C and 4 h respectively. To verify the wear computational results, 16 groups of PWHT orthogonal wear tests were performed at a temperature of 400 °C, which is a similar temperature to that occurs in an actual hot forging die. The wear-test result showed a good agreement with the FE simulation. SEM observation of the wear debris on 16 specimens showed that oxidative wear is dominant when the temperature was in 400 °C. Furthermore, when tempering temperature and holding time were 550 °C and 4 h respectively, the carbide alloy dispersively distributes in the metallographic structure, which helps to improve the wear resistance of the surfacing layer.

  19. 双螺旋流变压铸AZ91D镁合金的研究%Rheo-Die Casting of AZ91D Magnesium Alloy by Twin-Screw Stirring

    马跃宇; 杨必成; 王亚宝; 徐骏


    液态压铸是镁合金最主要的成形方式,但液态压铸件存在气孔等缺陷,限制了镁合金的进一步推广使用.介绍了采用双螺旋流变制浆技术,对镁合金AZ91D进行了流变压铸研究.首先,将镁合金AZ91D熔体浇入到双螺旋流变制浆机中,然后根据不同工艺参数制备流变镁合金浆料,待制浆结束后,将半固态浆料转移到压铸机内,制得半固态压铸件.采用Micro-Image Analysis&Process(MIAP)软件分析了双螺旋流变制浆工艺参数(搅拌温度、搅拌时间和转速)对镁合金AZ91D的初生相晶粒大小的影响,并研究了镁合金压铸成形性.结果表明:随着搅拌温度的降低,晶粒尺寸变化不是很大;随着搅拌时间延长,镁合金晶粒尺寸逐渐增大;随着搅拌速度的增加,镁合金平均晶粒尺寸减少.镁合金流变压铸件中的初生α相由搅拌中形成的球状晶及压铸过程中二次凝固形成的更为细小的球状晶组成.对比了普通压铸件与流变压铸件热处理后的力学性能,流变压铸件的力学性能得到大幅提高,其原因归结为铸态组织的细小和均匀化.%The liquid die casting is the main forming technique of magnesium alloys. However, in die cast components, some defects such as pores and so on restrained further applications of magnesium alloys. In this paper, rheo-die casting of AZ91D magnesium alloy prepared by twin-screw stirring technique was studied. Firstly, AZ91D magnesium alloy melt was put into a twin-screw stirring machine ; then, rheo-slurries were fabricated by twin-screw stirring according to different parameters. Lastly, the slurries were transferred into a die casting machine and rheo-die casting components were made. Effects of rheo-slurries processing parameters (temperature, time and speed) on the sizes of primary phase and performances of the die cast components were researched. The results showed that the grains changed little with the temperatures decreasing. When

  20. Effects of deformation temperature and rate on compressive deformation behaviour of Y 112 die cast aluminum alloy in semi-solid state

    YANG Ming-bo; HU Hong-jun; TANG Li-wen; DAI Bing


    The semi-solid compression deformation behaviour of Y112 die casting aluminum alloy with nondendritic structure obtained under the semi-solid isothermal treatment condition of 570 ℃ and 120 min, was investigated by means of Gleeble-1500 thermal-mechanical simulator. The results show that, when the strain is lower than 0.8, along with the compression strain increasing,the compression stress firstly increases rapidly, then decreases gradually. Under the condition of different deformation temperatures and deformation rates, the maximium compression stress is obtained simultaneously when the strain is 0.07 approximately.Furthermore, when the deformation rate keeps a constant, the compression stress decreases along with the deformation temperature increasing, and when the deformation temperature keeps a constant, the compression stress increases along with the deformation rate increasing.

  1. 基于神经网络与遗传算法的压铸工艺参数优化%Optimization of die casting processing parameters based on BP neural network and GA algorithm

    王成勇; 朱汝城; 王婉璐; 李亨; 刘全坤; 周慧杰


    According to the feature of high pressure die casting of A356 coffee machine dome, the die casting process of coffee machine dome was simulated by finite element simulate software.The L16 (45 )-orthogonal experiments and six complementary experiments were chosen as the trained samples of Back Propagation Neural Network.The major processing parameters of die casting were pouring temperature, mould pre-heated temperature, injection pressure and injection speed.The non-linear mapping between these processing parameters and thermal stress of die casting mould were built up.In order to get the minimum heat stress of die casting mould, the die casting processing parameters were optimized by GA algorithm.The best combination processing parameters of pouring temperature, mould pre-heated temperature, injection pressure, injection speed were found.Under these process parameters, the experimental index (σ)max became low, the trend of mold fatigue was reduced and the quality of casting was improved.The experiment results validate the feasibility of this optimization on reducing the thermal fatigue of mould and provide guidance on producing similar die casting parts.%依据A356咖啡机顶盖高压铸造特点,采用FEM仿真软件对铸件成型工艺进行数值模拟,以L16(45)正交试验和6个补充试验作为BP神经网络的训练样本,建立模具热应力与浇注温度、模具预热温度、压射比压、压铸速度4个压铸工艺参数的非线性映射关系;以模具热应力θmax的最小值为优化目标,运用遗传算法进行工艺参数优化.最终得出浇注温度、模具预热温度、压射比压、压铸速度等4个参数最佳的一组组合,使试验指标θmax最小,模具的热疲劳趋势最低,零件的成型质量最佳.试验结果证明,该减少模具热疲劳趋势的优化方案具有可行性,同时对相近结构压铸件的生产也具有一定的指导意义.

  2. CA Investment Casting Process of Complex Castings


    CA (Computer aided) investment casting technique used in superalloy castings of aerospace engine parts was presented. CA investment casting integrated computer application, RP (Rapid Prototyping) process, solidification simulation and investment casting process. It broke the bottle neck of making metal die. Solid model of complex parts were produced by UGII or other software, then translated into STL(Stereolithography) file, after RP process of SLS(Selective Laser Sintering), wax pattern used in investment ...

  3. Selected aspects of the piece production of iron alloy castings in terms of their environmental impact

    Z. Maniowski


    Full Text Available Problems of environmental protection are nowadays one of the top priorities in a policy programme adopted by the European Community.Reducing the negative impact of the domestic foundry industry on environment should result from complex and long-lasting activities,targeted not only at modernisation of the dust collecting units, but also at searches and implementation of alternative, innovative and more pro-ecology oriented means and techniques of casting manufacture. Reducing to minimum the level of emissions escaping to the environment should be considered at all stages of the casting manufacturing process. In this study, the discussion was restricted to the process of the manufacture of moulds and cores for piece production of the heavy castings. The environmental impact of the technology of making moulds and cores in sands with chemical binders, used most often in piece production of large castings poured from iron alloys, was highlighted. As an alternative technology of mould preparation for the piece production of castings, the ecological and economic aspects of the full mould process were presented.

  4. The skin effect and the yielding behavior of cold chamber high pressure die cast Mg-Al alloys

    Yang, K. Vanna [ARC Centre of Excellence for Design in Light Metals, Materials Engineering School of Engineering, University of Queensland, Brisbane, QLD, 4072 (Australia); Caceres, C.H., E-mail: [ARC Centre of Excellence for Design in Light Metals, Materials Engineering School of Engineering, University of Queensland, Brisbane, QLD, 4072 (Australia); Nagasekhar, A.V. [ARC Centre of Excellence for Design in Light Metals, Materials Engineering School of Engineering, University of Queensland, Brisbane, QLD, 4072 (Australia); Easton, M.A. [CAST Co-operative Research Centre, Department of Materials Engineering Monash University, Melbourne, VIC, 3800 (Australia)


    Highlights: Black-Right-Pointing-Pointer The area fraction of elastic skin was calculated for a range of Mg-Al alloys. Black-Right-Pointing-Pointer The skin was defined using micro mechanistic concepts and tensile testing data. Black-Right-Pointing-Pointer The elastic constraint imposed by the skin on the core is discussed. Black-Right-Pointing-Pointer The skin covers {approx}30% of the cross section of the most concentrated alloy. - Abstract: The volume fraction of material that remained elastic as yielding developed in cast-to-shape tensile specimens of binary alloys with Al contents between 0.47 and 11.6 mass% was calculated using the Kocks-Mecking method of analysis. In the most dilute alloys the elastic fraction decreased rapidly to zero at a well-defined stress, suggesting that yielding was uniform across the specimen, whereas in the concentrated ones it decreased gradually over a wide range of stresses, suggesting that yielding developed first in the softer core of the casting while the harder outer layer, or skin, remained elastic. Comparison with specimens of the concentrated alloys which had a surface layer removed showed that the strain hardening behavior of the core resembled that of full specimens of the most dilute alloy. The maximum amount of elastic material in comparison with the most dilute alloy was used to define the area fraction covered by the skin, for each alloy. The skin covered between {approx}10% and {approx}30% of the cross section, the greater values for the concentrated alloys. The skin imposed an elastic constraint that delayed the development of full plasticity at the core.

  5. Tribological behaviour of plasma nitrided cast iron D6510 and cast steel S0050A under the inclined-impact sliding condition with extremely high contact pressure

    Zhao, C.; Zhang, J.; Nie, X.


    Plasma nitriding as a surface modification was applied on two substrate materials: cast iron D6510 and cast steel S0050A. After measurement of the friction coefficients of the treated samples using a pin-on-disc tribotester, an inclined impact-sliding wear tester was utilized to investigate their tribological behaviour under tilting contact with extremely high contact pressure. While numerous surface fatigue cracks, severe chipping, and peeling of the compound layer were observed for the treated cast steel sample, the treated cast iron sample had far fewer surface fatigue cracks without chipping or peeling of the compound at the same test condition. The governing mechanisms of the treated cast iron sample’s superior resistance to surface fatigue failure were revealed by studying the cross-sectional hardness and nitrogen concentration profile. Energy-dispersive X-ray spectroscopy (EDS) analysis indicated that the treated cast iron sample had a smaller nitrogen concentration gradient, which led to a smaller hardness gradient as measured. The results suggest that a smaller hardness gradient between the compound layer and the diffusion zone and a thicker hardened case was able to improve the wear resistance and surface fatigue cracking resistance against high contact loads. Moreover, the smaller friction coefficient of the treated cast iron sample could also be beneficial for improving the wear resistance.

  6. 某缸体铝合金金属型低压铸造工艺研究%Study on Low Pressure Die Casting Process of A356 Aluminum Alloy Cylinder

    王狂飞; 王凯; 王有超; 米国发


    利用ViewCast软件对低压金属型铝合金A356铸造过程进行了计算机模拟,预测了产生缩孔、缩松缺陷的位置.通过计算机模拟以及对铸件表面缺陷进行分析,提出了生产工艺方案,铸造出了满足质量要求的铸件.所铸的铸件表面质量好、无缩松等铸造缺陷.这为铝合金金属型低压铸造模具设计及工艺研究提供了有价值的参考.%The low pressure die casting process of A356 aluminum alloy was simulated by ViewCast software, and the location of the shrinkage defects was forecasted. The producing process was proposed by computer simulating and analyzing the surface defect of the aluminum alloy castings. Regular castings were produced, the surface quality was obviously improved and no defects such as shrinkage were found. It provides the valuable reference for the research of low pressure die casting process and mold design of aluminum alloy permanent mold.

  7. Influence of isothermal quenching of LAMC CrMnSi cast steel on impact toughness

    JIN Bao-shi; HUANG Zhi-qiu; SHEN Da-dong


    The influence of isothermal quenching process of low-alloy and medium carbon (LAMC) CrMnSi cast steel on the impact toughness was investigated. The microstructure and mechanical property of LAMC CrMnSi cast steel were analyzed by the laser optical modulator, the scanning electron microscopy, the energy dispersive spectrometer, the hardness and impact tests. The experimental results show that the dual phases of bainite and residual austenite can be obtained by the severity isothermal quenching, the fractographies of specimens change from quasi-cleavage to dimple at 310 ℃ for 60 min, the impact toughness for specimens at the room temperature isothermally achieves 130 J/cm2, meantime and its hardness is more than 45(HRC).

  8. Evolutions of Advanced Stamping CAE — Technology Adventures and Business Impact on Automotive Dies and Stamping

    Wang, Chuantao (C. T.)


    In the past decade, sheet metal forming and die development has been transformed to a science-based and technology-driven engineering and manufacturing enterprise from a tryout-based craft. Stamping CAE, especially the sheet metal forming simulation, as one of the core components in digital die making and digital stamping, has played a key role in this historical transition. The stamping simulation technology and its industrial applications have greatly impacted automotive sheet metal product design, die developments, die construction and tryout, and production stamping. The stamping CAE community has successfully resolved the traditional formability problems such as splits and wrinkles. The evolution of the stamping CAE technology and business demands opens even greater opportunities and challenges to stamping CAE community in the areas of (1) continuously improving simulation accuracy, drastically reducing simulation time-in-system, and improving operationalability (friendliness), (2) resolving those historically difficult-to-resolve problems such as dimensional quality problems (springback and twist) and surface quality problems (distortion and skid/impact lines), (3) resolving total manufacturability problems in line die operations including blanking, draw/redraw, trim/piercing, and flanging, and (4) overcoming new problems in forming new sheet materials with new forming techniques. In this article, the author first provides an overview of the stamping CAE technology adventures and achievements, and industrial applications in the past decade. Then the author presents a summary of increasing manufacturability needs from the formability to total quality and total manufacturability of sheet metal stampings. Finally, the paper outlines the new needs and trends for continuous improvements and innovations to meet increasing challenges in line die formability and quality requirements in automotive stamping.

  9. 不锈钢管镶嵌件在压铸中的应用研究%Research and Application of Inserts of Stainless Steel Tube in Die Casting



    阐述了汽车发动机电控冷却器压铸件不锈钢油管内镶嵌件的结构、定位及工艺过程控制.其要点是,在油管接头上预先按图纸尺寸要求钻攻底孔、攻牙及铣面,同时做出与之配合的镀锌螺栓接头,装配后(将螺栓接头旋入油管接头内,成为油管总成,再放到压铸模上)通过与模具上的限位镶块精确定位,从而实现铸件压铸后油管接头位置度及接头端面的距离尺寸不变的目的.压铸结束后拆除可循环利用的螺栓接头,镀锌接头涂层防止了高温下因油污引起的生锈,满足了产品的清洁度要求.%According to the product assembly requirements, first pre-drilling thread bottom hole, tapping and milling surface in the tube union required by the drawing, and make the galvanized thread plug at the same time, the thread plug is screwed into the tube union as a tube assembly, and then put it into the casting mold . The tube dimensions of the casting would be achieved directly by the die casting process through die-casting mould precision limit insert . When the die casting is complete, remove the recyclable thread plug . The galvanized thread plug can prevent effectively metal from rust caused by the high temperature and oil of the fitting surface between the tube union and the thread plug to ensure the cleanliness requirement, and protect the tube surface against damage . The internal thread of the tube u-nion ensure the tooth shape in the thread plug force in the die casting process, so as to achieve the purpose of directly by the die-casting process. Reduce the cost under the precondition to satisfy the production requirements.

  10. Evaluation of the impact of solder die attach versus epoxy die attach in a state of the art power package

    Czernohorsky, J; Viering, Matthias; Wright, L; Balanon, G


    Subject of this paper is the thermal investigation of epoxy (EDA) and solder (SDA) die attaches by a comparison of an ASIC with multiple heat sources in different package assemblies. Static and transient thermal measurements and simulations were performed to investigate the thermal behavior of two samples in a state of the art QFP power package differing only in the die attach material (EDA and SDA).

  11. Cumulated energy consumption - fabrication of cast iron pieces. Vol. 1: Methods of evaluation and analysis of foundries. Vol. 2: Energy consumption of metal cutting processes. Vol. 3: Development of a model for material and energy consumption analysis in casting processes. Final report; Kumulierter Energieaufwand - Gussteilfertigung. Bd. 1. Teilthema: Methodik der Auswertung und Analyse von Giessereien. Bd. 2. Teilthema: Energieaufwand in der spanabhebenden Teilefertigung. Bd. 3. Teilthema: Entwicklung eines Modells zur Stoff- und Energiemengenanalyse fuer die Herstellung von Gussteilen. Abschlussbericht

    Ketscher, N.; Herfurth, K.; Kademann, R.; Wohlgemuth, H.; Huppertz, A.


    Development of materials, energy and carbon dioxide balances, acquisition and recording of data on casting and metal cutting processes, with selected examples of the 9 participating partners of the casting industry. [German] Erarbeitung von Stoff-, Energie- und CO{sub 2}-Bilanzen, Erfassung und Ermittlung von Daten fuer die Formgebung durch Giessen und die spangebende Bearbeitung an ausgewaehlten Beispielen der 9 beteiligten Firmen der Giessereiindustrie. (orig.)

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

    Korti, Abdel Illah Nabil; Abboudi, Said


    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.

  13. 压铸建压过程与建压时间浅析%Relationship between Pressure-Establishment and Time-Establishment during Die Casting

    卢宏远; 赵希文; 董亚明; 邹宪福; 丁晔平


    With the increasingly improvement of function and control of pressurization mechanism in the die casting machine, time-establishment , which has been as a controllable factors, was paid attention to. Through analyzing the working mechanism of accumulator, pressure-increment process of injection and pressurization mechanism, pressurization control mode and time-establishment, the minimum time-establishment and key factors influencing time-establishment were presented.%随着压铸机增压机构功能和控制的不断完善,建压时间已成为压铸工艺中的可控因素而受到普遍重视.通过对蓄能器的工作原理、压射及增压机构的升压过程、增压控制模式及建压时间等内容的简要分析,说明了在正常的三段建压过程模式下,目前压铸机能够达到的最短建压时间大约为30 ms,而内浇口厚度、铸件几何特征、合金凝固特性及工艺条件等是确定最短建压时间的主要因素.

  14. 压铸模具产品FDM快速成型工艺设计%Process design for die casting products with FDM rapid prototyping



    Analyzing die casting products FDM rapid prototyping process, using processing software to fine STL data, choosing excellent moulding material, optimizing forming parameters reasonablely, determining optimum forming direction and using ultrasonic removal of water soluble machine to remove supporting materials, advantages of FDM rapid prototyping was brought into full play. Practices had proven that the developed cycle was shortened and the manufacture speed was improved with FDM rapid prototyping and thus product development efficiency was improved by 42 percent to 58 percent.%对压铸模具产品FDM快速成型的工艺进行分析,应用处理软件精细化STL数据,通过选择优良的成型材料,合理优化成型参数,确定最佳成型方向,采取超声波水溶机去除支撑材料等手段来充分发挥FDM快速成型工艺的优势.实践证明,FDM快速成型技术在产品开发中缩短了产品开发周期,提高了制造速度,使产品开发效率提高42%~58%.

  15. Effects of silicon contents on formation of abnormal structures of aluminum alloy die castings; Aruminiumu gokin daikasuto no ijo soshiki keisei ni oyobosu keisoryo no eikyo

    Komazaki, T.; Maruyama, Y.; Nishi, N. [Ryobi Ltd., Hiroshima (Japan)


    In this study, Al-5-11mass%Si binary alloys and commercial alloys with equivalent amount of silicon contents (AC2A, ADC10, ADC12) were fabricated into die castings with changed shot-time-lag, and effects of alloy structures on formation of abnormal structures were investigated. The results show the following discoveries. With the increasing of silicon contents in Al-Si binary alloys from 5 mass% to 11 mass%, the abnormal structures caused by the cooling and solidification of the molten metal in the injection sleeve will change from mainly coarse {alpha} phase to mainly breaking chill crystals as the solidification state is changing form porridge state to solid surface forming state. The abnormal structure of the commercial alloy AC2A mainly consists of coarse {alpha} phases and that of ADC12 mainly consists of breaking chill crystals. The ADC10 alloy is an intermediate alloy between them. The amount of dispersion for values of tensile strength of ADC12 alloy is larger than that of AC2A and ADC10 alloys because ADC12 alloy contains many breaking chill crystals. 12 refs., 11 figs., 4 tabs.

  16. Selected aspects of the piece production of iron alloy castings in terms of their environmental impact

    Z. Maniowski; M. Młynski; Z. Sierant; Z. Żółkiewicz


    Problems of environmental protection are nowadays one of the top priorities in a policy programme adopted by the European Community.Reducing the negative impact of the domestic foundry industry on environment should result from complex and long-lasting activities,targeted not only at modernisation of the dust collecting units, but also at searches and implementation of alternative, innovative and more pro-ecology oriented means and techniques of casting manufacture. Reducing to minimum the le...

  17. Influence of Composition on the Environmental Impact of a Cast Aluminum Alloy

    Patricia Gómez


    Full Text Available The influence of alloy composition on the environmental impact of the production of six aluminum casting alloys (Al Si12Cu1(Fe, Al Si5Mg, Al Si9Cu3Zn3Fe, Al Si10Mg(Fe, Al Si9Cu3(Fe(Zn and Al Si9 has been analyzed. In order to perform a more precise environmental impact calculation, Life Cycle Assessment (LCA with ReCiPe Endpoint methodology has been used, with the EcoInvent v3 AlMg3 aluminum alloy dataset as a reference. This dataset has been updated with the material composition ranges of the mentioned alloys. The balanced, maximum and minimum environmental impact values have been obtained. In general, the overall impact of the studied aluminum alloys varies from 5.98 × 10−1 pts to 1.09 pts per kg, depending on the alloy composition. In the analysis of maximum and minimum environmental impact, the alloy that has the highest uncertainty is AlSi9Cu3(Fe(Zn, with a range of ±9%. The elements that contribute the most to increase its impact are Copper and Tin. The environmental impact of a specific case, an LED luminaire housing made out of an Al Si12Cu1(Fe cast alloy, has been studied, showing the importance of considering the composition. Significant differences with the standard datasets that are currently available in EcoInvent v3 have been found.

  18. Influence of Composition on the Environmental Impact of a Cast Aluminum Alloy.

    Gómez, Patricia; Elduque, Daniel; Sarasa, Judith; Pina, Carmelo; Javierre, Carlos


    The influence of alloy composition on the environmental impact of the production of six aluminum casting alloys (Al Si12Cu1(Fe), Al Si5Mg, Al Si9Cu3Zn3Fe, Al Si10Mg(Fe), Al Si9Cu3(Fe)(Zn) and Al Si9) has been analyzed. In order to perform a more precise environmental impact calculation, Life Cycle Assessment (LCA) with ReCiPe Endpoint methodology has been used, with the EcoInvent v3 AlMg3 aluminum alloy dataset as a reference. This dataset has been updated with the material composition ranges of the mentioned alloys. The balanced, maximum and minimum environmental impact values have been obtained. In general, the overall impact of the studied aluminum alloys varies from 5.98 × 10(-1) pts to 1.09 pts per kg, depending on the alloy composition. In the analysis of maximum and minimum environmental impact, the alloy that has the highest uncertainty is AlSi9Cu3(Fe)(Zn), with a range of ±9%. The elements that contribute the most to increase its impact are Copper and Tin. The environmental impact of a specific case, an LED luminaire housing made out of an Al Si12Cu1(Fe) cast alloy, has been studied, showing the importance of considering the composition. Significant differences with the standard datasets that are currently available in EcoInvent v3 have been found.

  19. The Nonlinear Predictive Control of Die Casting Machine for Multivariable Injection Process%压铸机多变量压射过程非线性预测控制

    陈伟华; 彭继慎; 赵忠建


    In the electric hydraulic servo control system during injection process of die casting machine,this paper presents a nonlinear-predictive-control method of die casting machine for multivariable injection process based on adaptive differential chaotic evolutional algorithm.The tent map is embedded into the adaptive differential evolution algorithm (DE),which has improved the generating process of DE algorithm for the crossover factor and compiling factor.The results of simulation experiment show that by using the intelligent algorithm to optimize injection parameters of die-casting PID controller,we can achieve fast optimization of die-casting machine injection speed and make the dynamic characteristics of nonlinear predictive control better,and the control precision more higher,so as to achieve the optimal-control purpose for the system.%在压铸机压射过程的电液压伺服控制系统中,提出了一种基于混沌自适应差分进化算法(CADE)的压铸机多变量压射过程非线性预测控制方法.该方法将帐篷映射嵌入到自适应差分进化算法(DE)中,改进了DE算法中交叉因子及编译因子的产生过程.通过仿真实验结果表明,利用该智能算法对压射控制PID控制器进行参数优化,能实现压铸机压射速度的快速寻优,使其非线性预测控制动态特性更好,控制精度更高,从而达到系统的最优控制目的.

  20. Application of Using Ultra-Low-Speed Die Casting the Support Bracket of Automobile Engine Transmission%汽车发动机变速箱支架类零件的超低速压铸工艺

    刘春生; 苏建强; 罗金祺


    针对传统压铸工艺在生产超厚型产品时存在的气孔率高、强度低等问题,研究开发了某发动机支架零件的超低速压铸工艺,讨论了不同压射速度、内浇口厚度、浇注温度以及模具结构和模温控制等因素对压铸产品质量的影响.结果表明,当低速压射速度为0.25 m/s,高速压射速度为0.5 m/s,内浇口厚度为5.2 mm,浇注温度为680~690℃时,获得的铸件质量最好.通过对超低速压铸模具结构进行改进,并采用顺序凝固模温控制方法,满足了对铸件进行T6热处理的要求,使产品性能有较大提升.%aiming at problems existed in the traditional die casting super-thickness product, such as high porosity, low strength, the ultra-low-speed die casting engine support bracket was conducted, and effects of different injection speed, the thickness of ingate, pouring temperature of liquid metal, the mould structure and the control methods of the mould temperature on the quality of die casting support bracket were discussed. The results show that the support bracket exhibits acceptable quality with low injection speed of 0. 25 m/s and high injection speed of 0. 5 m/s, thickness of ingate of 5. 2 mm as well as pouring temperature of 680~690 ℃. Through modifying die casting die structure and adopting the sequential solidification mould temperature, the support bracket ca be treated by T6 heat treatment, improving greatly the performance of the die castings.

  1. Application of Low Temperature Liquid Sulfurization Catalyzed with Rare Earth on Cr12 Impacting Die


    One kind of quenched Cr12 steel dies for impacting stainless steel wire rope (SSWR) was treated by low temperature liquid sulfurization catalyzed with rare earths, in order to extend their service life for assuring the continuity of production line, and simultaneously improve the surface quality of SSWR obtained. After immerged into the melting sulphur containing 4%(mass fraction) of LaF3 and 1% of CeCl3 at 463 K for 4 h, the sulfurized dies were very smooth and black, with little distortion and hardness loss. They exhibited a certain extent of corrosion-resistance in air due to the coexisting rare earths in the sulfurized layer. Optical observations showed that the sulfurized layer was uniform and had scale-like structure. The trail of machined SSWR indicated that the production capacity of sulfurized dies had been doubled and the replacing period on line was postponed. SEM morphology also proved that the wear extent of cavities on sulfurized dies decreased greatly and the surface quality of SSWR obtained was improved markedly.

  2. J1140型压铸机增压控制油路设计特点与应用%Design Features and Application of Booster Pressure Control Circuit for J1140 Type Die-casting Machine



    According to the requirements of J1140 type die-casting machine injection system, boost pressure control circuit was designed. The problem for the change of injection process parameters due to artificial pouring amount different was solved. So the qual-ity stability of die-casting machine parts production is improved, injection force can be adjusted in a wide range, the process-range of die-casting machine is expanded.%根据J1140型压铸机压射系统的要求, 设计增压控制油路, 解决了由于人工浇筑量的不同而造成的压铸工艺参数变化的问题, 提高了压铸机生产零件质量的稳定性, 压射力可在较大范围内进行调整, 扩大了压铸机的工艺范围.

  3. Impact characteristics of austempered spheroidal graphite cast steel. Austemper kyujo kokuen chuko no shogeki tokusei

    Takahashi, T.; Tada, S.; Abe, T. (Government Industrial Research Institute, Tohoku, Sendai (Japan))


    Austempered ductile cast iron (ADI) has excellent mechanical properties both in strength and toughness, but the Young's modulus of ADI is lower than that of steel because ADI contains much graphite. In order to obtain better mechanical properties than ADI, spheroidal graphite cast steel containing less graphite by volume was austempered. The Young's modulus of austempered spheroidal graphite cast steel (AGS) was 200 GPa, which was comparable to steel. The retained austenite volume of the sample containing 2.4% Si varied with the austempering conditions, but that of the sample containing 1.4% Si decreased in a shorter austempered time. As a result, it was found that Si affects stability of the retained austenite. Charpy impact value increased with increasing the retained austenite volume when the volume was above 15%. The impact value of AGS with 40% retained austenite was over twice as large as that of ADI austempered under the same conditions. 21 refs., 8 figs., 1 tab.

  4. Tensile Properties and Fracture Behavior of Aluminum Alloy Foam Fabricated from Die Castings without Using Blowing Agent by Friction Stir Processing Route

    Yoshihiko Hangai


    Full Text Available Al foam has been used in a wide range of applications owing to its light weight, high energy absorption and high sound insulation. One of the promising processes for fabricating Al foam involves the use of a foamable precursor. In this study, ADC12 Al foams with porosities of 67%–78% were fabricated from Al alloy die castings without using a blowing agent by the friction stir processing route. The pore structure and tensile properties of the ADC12 foams were investigated and compared with those of commercially available ALPORAS. From X-ray computed tomography (X-ray CT observations of the pore structure of ADC12 foams, it was found that they have smaller pores with a narrower distribution than those in ALPORAS. Tensile tests on the ADC12 foams indicated that as their porosity increased, the tensile strength and tensile strain decreased, with strong relation between the porosity, tensile strength, and tensile strain. ADC12 foams exhibited brittle fracture, whereas ALPORAS exhibited ductile fracture, which is due to the nature of the Al alloy used as the base material of the foams. By image-based finite element (FE analysis using X-ray CT images corresponding to the tensile tests on ADC12 foams, it was shown that the fracture path of ADC12 foams observed in tensile tests and the regions of high stress obtained from FE analysis correspond to each other. Therefore, it is considered that the fracture behavior of ADC12 foams in relation to their pore structure distribution can be investigated by image-based FE analysis.

  5. Die Casting Semi-Solid ZL101 Alloy Prepared by Inclined Slope Cooling-Transferring Method and its Properties%ZL101过流冷却转移法半固态压铸工艺及性能研究

    李璐; 周荣锋; 岑启宏; 黎振华; 蒋业华; 周荣


    Die casting semi-solid ZL101 alloy prepared by inclined slope cooling-transferring method was conducted. Effects of processing parameters on properties of semi-solid rheoforming ZL101 alloy die castings were investigated, and the change of properties of the semi-solid die casting ZL101 parts after T6 heat treatment was analyzed. Mechanical properties of semi-solid die casting parts were comparatively analyzed with those of conventional die casting parts. The results reveal that, the semi-solid die casting parts exhibit desirable mechanical properties with pouring at 595 ℃ and injecting at 1. 8 m/s, and the elongation is increased by 11% compared with that of conventional die casting parts at 630 ℃. Tensile strength and elongation of the semi-solid die casting parts after heat treatment are greatly improved. The fracture mechanism of both conventional die casting parts and semi-solid die casting parts are characterized by quasi-cleavage fracture, while semi-solid die casting parts after heat treatment are characterized by ductile fracture.%采用倾斜管过流冷却-转移法生产半固态流变压铸件,研究了压铸工艺对ZL101铝合金半固态流变压铸件性能的影响,以及半固态压铸件经T6热处理之后性能的改变.对比研究了液态与半固态压铸件的力学性能.结果表明,在浇注温度为595℃、压射速度为1.8 m/s时,压铸件性能最佳,此时较浇注温度为630℃的液态压铸件的抗拉强度提高了11%.经热处理的半固态压铸件抗拉强度与伸长率都得到改善.液态与半固态压铸件试样的拉伸断口为准解理断裂,经热处理的半固态压铸件试样的拉伸断口为韧性断裂.

  6. Numerical Simulation of Semi-Solid Die Casting of Barrel Shell%“筒壳”铸件半固态压铸过程数值模拟



    采用铸造模拟软件ProCAST对腔深、壁薄的A356合金的“筒壳”铸件进行模拟分析.通过对其压铸过程中的温度场进行数值模拟、分析,预测缩孔缩松所在的位置及大小.优化出最佳工艺参数:浇注温度为590℃,压射速度为5 m/s,模具温度为220℃.在此工艺条件下A356半固态浆料充型平稳,温度场分布均匀,无飞溅卷气和浇注不足等缺陷,在实际生产中获得了质量完好的铸件,验证了该工艺参数.%The die cast "barrel shell" casting with deep cavity and thin wall was simulated by casting simulation software ProCAST. By making casting simulation on casting process and temperature field, the location and sizes of shrinkage and dispersed shrinkage were forecasted. The optimized parameters are: pouring temperature 590 ℃, injection speed 5 m/s, mold temperature 220 ℃. Under this process, semi-solid slurry mold filling is stable, temperature field is uniform and there were no casting defects such as splash air entrapments and misrun. The process parameters were proved by obtaining perfect part quality in actual production.

  7. The evaluation of dynamic cracking resistance of chosen casting alloys in the aspect of the impact bending test



    Full Text Available The increase of quality and durability of produced casting alloys can be evaluated on the base of material tests performed on a high level. One of such modern test methods are tests of the dynamic damage process of materials and the evaluation on the base of obtained courses F(f, F(t of parameters of dynamic cracking resistance KId, JId, performed with the usage of instrumented Charpy pendulums. In the paper there was presented the evaluation of dynamic cracking resistance parameters of casting alloys such as: AK12 aluminum alloy, L20G cast steel and spheroid cast iron. The methodology of the evaluation of that parameters was described and their change as well, for the AK12 alloy with the cold work different level, L20G cast steel cooled from different temperatures in the range +20oC -60oC, and for the spheroid cast iron in different stages of treatment i.e. raw state, after normalization, spheroid annealing and graphitizing annealing.Obtained parameters of dynamic cracking resistance KId, JId of tested casting alloys enabled to define the critical value of the ad defect that can be tolerated by tested castings in different work conditions with impact loadings.

  8. Development and Application of Hot Rectification Technology in Al Alloy Die Castings%铝合金压铸件热矫形技术的开发与应用

    黄志垣; 万里; 张百在; 陈亮; 池晓钦; 陈毅廷; 余亮; 徐飞跃


    零件变形是压铸生产中经常遇到且难以完全消除的主要缺陷之一,矫形是减轻零件变形量的有效手段.针对压铸生产中人工矫形方法存在效率低、工作量大、工作环境恶劣的缺点,开发了一种适于铝合金压铸件的热矫形技术.结果表明,在铸件出模后立即实行热矫形并辅助于水冷,可有效降低零件的变形量,产品100%满足机加工的要求.该方法具有效率高、工人劳动强度低、环境噪音低的优点,可取代人工矫形方法.%Distortion is one kind of main defects occurred in the aluminum alloy die castings, which is difficult to fully be eliminated. Rectification is a key method to relieve the distortion of aluminum alloy die castings. A new hot rectification technology suitable for aluminum alloy die castings was developed to o-vercome the problems in low efficiency, high intensity and wicked environment in manual rectification condition. The distortion of the aluminum alloy parts can be effectively decreased by hot rectification combining with water cooling after ejection from the die, fully meeting the machining demand. The technology exhibits the advantages of high efficiency, low working intensity and low environmental noise.

  9. Die Casting Technology of Hypereutectic Al-Si Alloy Clutch Gear with High Strength and Wear Resistance%高强耐磨过共晶铝合金离合器齿轮的压铸技术

    万里; 杨剑霞; 刘后尧; 吴湛方; 陈国强; 赖沛基


    Aiming at die casting thick-walled ADC automobile clutch gear, P-Cu modification on hypereu-tectic Al-Si alloy suitable for die casting was conducted. Die casting scheme for clutch gear was designed and simulated, meanwhile, vacuum die casting and local pressurization technology were developed. The results show that with 0. 1 % P addition, ADC14 exhibits good modification effects with 6 h modification time, where primary Si phase in the alloy reaches 20~40 μm with uniform distribution, and the depth of Si particle depletion zone on surface of the castings is in the range of 0. 18~0. 20 mm. At given injecting parameters, the mechanical vacuum valve is superior to zig-zag valve in vacuum effects, and the rejected rate with gas hole is decreased by 10%. Shrinkage porosity (hole) at thick-wall of the gear can be effectively eliminated by optimized local pressurization, the quality of the gear is improved, and qualification rate of mass-production is more than 95%.%针对压铸成形的ADCl4汽车离合器齿轮厚壁部件,研究了适于压铸的过共晶Al-Si合金的P-Cu变质处理工艺.设计并模拟了齿轮的压铸工艺方案,开发了真空压铸及局部加压技术.结果表明,当P的加入量为0.1%时,ADC14的变质效果好,变质时间可达6h.铸件中初生Si尺寸为20~40 μm,分布均匀;铸件表面的Si贫乏区深度在0.18~0.20 mm范围内.在相同压射参数下,采用机械式真空阀比搓衣板式排气阀的真空效果好,铸件的气孔缺陷废品率下降10%以上.优化后的局部加压技术消除了厚壁部位的缩松缺陷,提高了铸件内部质量.批量生产合格率达95%以上.


    李帅君; 熊守美; Mei Li; John Allison


    通过对压铸充型过程中卷气缺陷形成机理的分析,认为型腔中空气的流动以及与金属液之间的相互作用是形成卷气现象的主要原因.为了考虑型腔中空气的流动,采用了一种不可压缩两相流数学模型来模拟压铸充型过程的卷气现象.通过计算流体力学中的两个基准算例,较为全面地验证了该模型的准确性和可靠性.在此基础上,设计了专门针对压铸充型过程的高速水模拟实验,通过对可视化实验结果与两相流模拟结果的比较,证实二者吻合较好,说明了该模型能够较好地模拟液体的充填行为和卷入其中的气泡.%The most common defect found in high pressure die casting (HPDC) process is the gas porosity which significantly affects the mechanical properties of the final components. The generation of gas porosity is known mainly due to the air entrapment in the liquid metal during the mold filling stage. Knowing the trapped-air location and amount could allow for a more accurate and objective analysis of casting quality. In the past few decades, extensive efforts have been made to develop simulation codes of casting flow. Most of these codes solve the velocity, pressure and fluid fraction only in the liquid phase with the assumption that the effect of air in the die cavity is negligible. As a matter of fact, the air in the die cavity has significant influence on the filling pattern of the molten metal and the gas porosity distribution of the die casts. Recently, following the development of computational fluid dynamics (CFD), two-phase flow models have drawn continuous attention in the numerical simulation of casting processes, but there are still few models and further studies are needed. In this study, the mechanism of the formation of air entrapment defects in the HPDC process was discussed and it turned out that the air flow in the die cavity as well as the interaction between air and liquid metal resulted in the final air

  11. Effect of Different Inoculants on Impact Toughness in High Chromium Cast Iron

    Siekaniec D.


    Full Text Available The present work, presented the study of effect of different inoculants on impact toughness in High Chromium Cast Iron. The molds were pouring in industrial conditions and samples were tested in laboratory in Faculty of Foundry Engineering at AGH. Seven samples were tested - one reference sample, three with different addition of Fe-Ti, and three with different addition of Al. The samples were subjected to impact toughness on Charpy hammer and the hardness test. The presented investigations indicate that for the each inoculant there is an optimal addition at which the sample obtained the highest value of impact toughness. For the Fe-Ti it is 0.66% and for Al is 0.17%. Of all the examined inoculants best results were obtained at a dose of 0.66% Fe-Ti. Titanium is a well-known as a good modifier but very interesting results gives the aluminum. Comparing the results obtained for the Fe-Ti and Al can be seen that in the case of aluminum hardness is more stable. The hardness of all samples is around 40-45 HRC, which is not high for this type of cast iron. Therefore, in future studies it is planned to carry out the heat treatment procedure that may improves hardness.

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

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


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

  13. Nonlinear Predictive Control for Real-time Control Injection System of Die-casting Machine Based on CADE Algorithm%基于CADE算法的压铸机实时控制压射系统的研究

    闫孝姮; 陈伟华; 彭继慎; 赵忠建


    A nonlinear predictive control algorithm was proposed for multivariable die-casting processes of die-casting machine based on chaos adaptive differential evolution model.In the adaptive differential evolution model,the tent map was embedded to improve the process of production of crossed factors and compile factor in the DE model.The simulation results show that the injection control PID controller with the intelligence algorithm can optimize the die-casting machine injection velocity and make the nonlinear predictive control possess good dynamic characteristics and high control precision to achieve the system optimal control objective in the end.%提出了一种基于混沌自适应差分进化算法(CADE)的压铸机多变量压射过程非线性预测控制.其将帐篷映射嵌入到自适应差分进化算法(DE)中,改进了DE算法中交叉因子及编译因子的产生过程.通过仿真试验,结果表明,利用该智能算法对压射控制PID控制器进行参数优化,能实现压铸机压射速度的快速寻优,使其非线性预测控制动态特性更好,控制精度更高,从而达到系统的最优控制目的.

  14. Design of Injection Cylinder for J1170 Horizontal Cold Chamber Die-casting Machine%J1170型卧式冷室压铸机压射缸结构设计



    The injection cylinder structure of J1170 horizontal cold chamber die-casting machine was designed,and the injection cylinder structure size was calculated.Combining with practical application,the characters of the design were analyzed.%设计J1170型卧式冷室压铸机压射缸结构,对压射缸的结构尺寸进行理论计算;结合实际应用,分析其设计特点.

  15. Die ideaal van die spreker in die satiriese gedig: M.M. Walters

    S. M. Cameron


    Full Text Available Wanneer van die satirikus gepraat word, word eintlik die spreker in die satiriese gedig veronderstel. “For the Muse ought always to be our reminder that it is not the author as man who casts these shadows on our printed page, but the author as poet” (Mack, 1971:193.

  16. Impact properties of the aircraft cast aluminium alloy Al-7Si0.6Mg (A357

    Alexopoulos N.D.


    Full Text Available The impact mechanical properties of the widely used in the aeronautics A357 cast aluminum alloy were investigated by exploiting experiments on an instrumented Charpy impact testing machine. The evaluated impact properties for 25 different artificial aging heat treatment conditions were analyzed and discussed in conjunction with the respective tensile properties. Correlations are proposed to establish useful relationships between impact resistance and tensile strain energy density properties. The established correlations, which are well supported by the performed experiments, can be used to estimate the tensile ductility and toughness of the A357 cast aluminum alloy from the Charpy impact test. Performed fractographic analyses were supporting the physically arbitrary correlation between tensile strain energy density and impact resistance.

  17. Impact properties of the aircraft cast aluminium alloy Al-7Si0.6Mg (A357)

    Alexopoulos, N. D.


    The impact mechanical properties of the widely used in the aeronautics A357 cast aluminum alloy were investigated by exploiting experiments on an instrumented Charpy impact testing machine. The evaluated impact properties for 25 different artificial aging heat treatment conditions were analyzed and discussed in conjunction with the respective tensile properties. Correlations are proposed to establish useful relationships between impact resistance and tensile strain energy density properties. The established correlations, which are well supported by the performed experiments, can be used to estimate the tensile ductility and toughness of the A357 cast aluminum alloy from the Charpy impact test. Performed fractographic analyses were supporting the physically arbitrary correlation between tensile strain energy density and impact resistance.

  18. Preparation of Wax-Emulsion Releasing Agent for Aluminium Alloy Die Casting%一种铝合金压铸蜡乳液脱模剂的研制

    吴国江; 曹桂芝; 江敏


    研究了用氧化聚乙烯蜡、58#全炼蜡制备铝合金压铸蜡乳液脱模剂的方法。考查了乳化剂类型、乳化剂用量、乳化工艺对乳液稳定性的影响。实验结果表明,当复合乳化剂用量为复合蜡的30%,乳化温度为95℃,搅拌速度为500~700 r/min时,乳化时间为40~45 min,可以制取一种稳定的用于铝合金压铸蜡乳液脱模剂。%A preparation method of wax-emulsion releasing agent for aluminium alloy die casting from oxidized polyethylene wax and 58# fully refined paraffin wax was studied. Effects of emulsifier type, emulsifier dosage and emulsifying process on the emulsion stability were studied. The results show that, when the compounded emulsifier dosage is 30%of the mixed wax mass, the emulsifying-temperature is 95℃, the stirring speed is between 500~700 r/min, the emulsifying time is between 40~45min, stable wax-emulsion releasing agent for aluminium alloy die casting can be prepared.

  19. Optimization of Die Casting Process for Al Alloy Standard Samples Based on CAE%基于CAE的铝合金标准试样的压铸工艺方案优化

    吴晗; 万里; 胡祖麒; 吴树森


    压铸工艺方案的合理性对标准压铸试样的力学性能具有重要影响.采用Flow-3D软件对现有推荐的标准试样压铸工艺方案进行了模拟分析和优化;同时设计和优化了适于高真空压铸的工艺方案.结果表明,现有的压铸工艺方案在低速充填阶段时,试样内浇道附近的横浇道中会出现金属液回流卷气现象.将直浇道与横浇道的过渡圆角加大到30 mm时,该回流卷气现象明显减小.改用锥形横浇道并辅以缓冲包结构时,回流和卷气部位则移至两端的缓冲包附近,可避免卷气的金属液进入试样型腔中,有利于铸件品质的改善.采用在试样溢流槽侧面设置排气道时,能有效消除不同试样间排气道的封闭现象,从而保证后充填试样有足够的排气时间,有利于铸件内部品质的提高.%Rationality of gating system in the die casting process has great effects on the mechanical properties of the standard casting samples. The Flow-3D software was employed to analyze and optimize the existed gating system of standard samples. Meanwhile, design and optimization of high vacuum die casting for standard samples were conducted. The results show that gas entrapment and liquid alloy back-flow occurred around the runner nearby the ingate during slow speed filling stage in the existing die casting process. And they could be significantly reduced with the transition angle between the sprue and the runner increasing to 30 mm, while tapered runner with buffer structure was adopted, the backflow and gas entrapment can be moved to the packet buffer, and the liquid metal with gas entrapment can be avoided before moving into cavity, which is beneficial for the improvement of die castings quality. Air vent located in the side of the overflow can effectively eliminate the blockage of exhaust passage among different samples, which ensures adequate exhausting time after the samples are filled completely. Therefore, the internal

  20. Y-chromosomal insights into the genetic impact of the caste system in India.

    Zerjal, Tatiana; Pandya, Arpita; Thangaraj, Kumarasamy; Ling, Edmund Y S; Kearley, Jennifer; Bertoneri, Stefania; Paracchini, Silvia; Singh, Lalji; Tyler-Smith, Chris


    The caste system has persisted in Indian Hindu society for around 3,500 years. Like the Y chromosome, caste is defined at birth, and males cannot change their caste. In order to investigate the genetic consequences of this system, we have analysed male-lineage variation in a sample of 227 Indian men of known caste, 141 from the Jaunpur district of Uttar Pradesh and 86 from the rest of India. We typed 131 Y-chromosomal binary markers and 16 microsatellites. We find striking evidence for male substructure: in particular, Brahmins and Kshatriyas (but not other castes) from Jaunpur each show low diversity and the predominance of a single distinct cluster of haplotypes. These findings confirm the genetic isolation and drift within the Jaunpur upper castes, which are likely to result from founder effects and social factors. In the other castes, there may be either larger effective population sizes, or less strict isolation, or both.

  1. A strategy for monitoring Swiss needle cast and assessing its growth impact in Douglas-fir plantations of Coastal Oregon

    Doug Maguire; Alan Kanaskie; Mike McWilliams


    Many Douglas-fir plantations along the north coast of Oregon are exhibiting severe symptoms of Swiss needle cast disease (SNC). These symptoms include premature loss of foliage, abundant fungal pseudothecia on needles, yellowing of foliage, and apparent reduction in diameter and height growth. The development of the disease and its impacts on growth are currently being...

  2. 电磁离心铸造对高铬铸铁冲击韧度的影响%Influence of Electromagnetic Centrifugal Casting on High Chromium Casting Iron Impact Toughness

    孙凯; 杨雪; 赵琳


    In order to improve the impact toughness of high chromium cast iron, centrifugal casting method was used on electromagnetic high chromium cast iron casting. The results show that the structure under electromagnetic centrifugal casting is refined; the number of grains increases; the grain size becomes smaller, the impact toughness and other mechanical performance are improved. When the centrifugal speed is 1800 r/min, the magnetic induction strength of 0.4T, the impact toughness after electromagnetic centrifugal casting cast is 6.9. Toughness increases compared with conventional samples.%为了提高高铬铸铁的冲击韧性,使用电磁离心铸造方法对高铬铸铁进行浇铸.结果表明:电磁离心铸造获得试样的组织明显细化,晶粒数量增多,晶粒尺寸变小,冲击韧度等力学性能提高.当离心转速为1800 r/min,磁感应强度为0.4T时,电磁离心铸造铸态试样的冲击韧度为6.9 J/cm2.冲击韧度较常规试样提高.


    王向杰; 游国强; 张均成; 龙思远


    Porosity has been a main problem for die casting magnesium alloy welding and casting defect repair. In order to study the formation mechanism of pores in fusion welding of die casting magnesium alloy, in this research, experiment of die casting AZ91D magnesium alloy CO2 laser re-melting was carried out. OM and SEM were employed to observe the characteristics of pores existing at both the base metal and re-melted zone, and a software for particle size analysis called nano measure 1.2 was adopted to measure the pores' size. During analysis, the work mainly focused on the relationship of pores in re-melted zone associated with that preexisting in the base metal. The results showed that: porosity in die cast magnesium alloy base metal showed apparently hereditary characteristic in the process of re-melting. Porosity preexisting in the die casting AZ91D magnesium alloy was mainly produced at the junction region of multi-grains, with high pressure of inner gas, small size and irregularity in shape. However, pores in the re-melting zone showed diversity. Specifically, the micro-pore was small in size, nearly round in cross section and smooth in the inner wall, which was induced by hydrogen stored in the base metal. The macro-pores were vermiculate, with gas channel and metal erosion traces at the inner wall. It's considered that the micro-pore was mainly inherited from the atomic hydrogen solution in the base metal and molecular hydrogen stored in the die casting defects.In the re-melting process, gas bubble of hydrogen was formed through nucleation and development two steps, and there was no sufficient time to grow up. As a result, the hydrogen induced pore was great in number and small in size. While the macro-pores were inherited from porosity preexisting in the base metal, the corresponded gas bubble did not require nucleation, was directly formed from the involved gas in preexisting porosity during die-casting process. Development of gas bubble for macro-pore mainly

  4. Influence of liquid surface segregation on the pitting corrosion behavior of semi-solid metal high pressure die cast alloy F357

    Moller, H


    Full Text Available Semi-solid metal processing results in liquid segregation at the surface of the components. The pitting behaviour of this surface layer of semi-solid metal processed alloy F357 was compared with the centre (or bulk) of cast plates in 3.5% Na...

  5. Effect of austempering temperature and time on the kinetics and microstructure of austempered compacted graphite cast irons; Einfluss von Zwischenstufenverguetungstemperatur und -zeit auf die Kinetik und die Mikrostruktur von zwischenstufenverguetetem, Gusseisen mit Vermiculargraphit

    Teymourian, Mehdi [LMI Co., Tehran (Iran, Islamic Republic of). Casting Dept.; Boutorabi, Seyed Mohammad Ali [Iran Univ. of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of). Center of Excellence for Advanced Materials


    After starting the austempering nucleation of bainitic ferrite was observed within a very short time. Samples that austempered for 2 min. showed martensite in the microstructure. By increasing the austempering time from 30 min to 90 min the retained austenite decomposes and X-ray diffraction observations revealed the greatest volume fraction of retained austenite up to 17.3 and 23.8 percent when austempered for 30 min. Micro-hardness of the bainitic Verbesferrite increased up to 370 and 500 HV and micro-hardness of the retained austenite increased up to 300 and 400 HV at the austempering temperatures of 300 C and 400 C respectively. In comparison to austempered ductile iron, the austempered compacted graphite cast iron shows higher rate of bainitic reaction. Bainite formation driving force and consequently the rate of austempering process are higher in compacted graphite cast irons. (orig.)

  6. High integrity automotive castings

    Weiss, D. [Eck Industries Inc., St. Manitowoc, WI (United States)


    This paper described the High Integrity Magnesium Automotive Casting (HI-MAC) program, which was developed to ensure the widespread adoption of magnesium in structural castings. The program will encourage the use of low pressure permanent molds, squeeze casting, and electromagnetic pumping of magnesium into dies. The HI-MAC program is currently investigating new heat treatment methods, and is in the process of creating improved fluid flow and solidification modelling to produce high volume automotive components. In order to address key technology barriers, the program has been divided into 8 tasks: (1) squeeze casting process development; (2) low pressure casting technology; (3) thermal treatment; (4) microstructure control; (5) computer modelling and properties; (6) controlled molten metal transfer and filling; (7) emerging casting technologies; and (8) technology transfer throughout the automotive value chain. Technical challenges were outlined for each of the tasks. 1 ref., 3 tabs., 5 figs.

  7. Numerical Simulation of Die Casting Technology on End Closure of Aluminium Alloy%铝合金端盖件压铸工艺的数值模拟



    运用铸造模拟软件Procast对一模四腔的A356铝合金压铸零件进行数值模拟,分析铸件的充型凝固过程,预测缺陷。结果显示:在压射速度为2.5m/s,浇注温度为650℃,模具温度为240℃的条件下四腔同时充填,充型平稳,排气良好,得到充型完整、无缩松缩孔、气孔倾向小的铸件。%The numerical simulation of filling and solidifying process alloy A356 casting with the mould of four cavities was performed with the casting simulation software Procast, and defect was forecasted according to the result's analysis. The technical parameters were as follows: injection speed of 2.5 m/s, pouring temperature of 650 ℃ ,mold initial temperature of 250 ℃, under which the four cavities were simultaneous and stably filled, and the castings of better quality were obtained.

  8. Die binding van die konfessie

    P. J. Coetzee


    Full Text Available Ons moet waak teen twee uiterstes. Aan die een kant het die dogma as onversoenlike vyand die dogmatisme en aan die ander kant die antidogmatisme — dit hou enersyds die gevaar in van verabsolutering (oorskatting, en ander- syds die gevaar van relativisme (onderskatting.

  9. Development of Injection System with Inner-Set Check Valve for Die Casting Machine%压铸机内置单向阀压射系统的研制

    孟凡义; 徐越; 崔嘉琪


    压铸机内置单向阀压射系统,主要解决传统压铸机利用浮动活塞增压的三级压射系统建压时间相对较长引起的缺陷问题.安装在增压活塞杆内的带弹簧复位的内置单向阀,可以借助弹簧的力量快速关闭锥面开始增压,缩短了建压时间.在压射活塞右端与内置单向阀之间增加压射活塞缓冲结构,慢压射时进油口的大小随着压射活塞移动而逐渐增加,实现了慢压射速度匀加速的目的.%Injection system with inner-set check valve for die casting machine was development to solve the problems of the long establishment-time in three-stage injection system in traditional die casting machine due to use floating piston to pressurization. Inner-set check valve with spring reset which was installed in pressurization piston rod could rapidly switch off cone face with the help of spring to shorten established-pressure time by pressurization. Injected piston buffer mechanism was designed between the right end of injected piston and inner-set check valve, so the size of oil entrance during slow injection process is increased gradually with the move of injected piston, realizing the proportional acceleration of slow injection velocity.

  10. Die instelling van die doop

    J. L. Venter


    Full Text Available Die eerste plek in die evangeliebeskrywings waar daar van die doop as ’n opdrag van Jesus Christus gepraat word en waar die betekenis die duidelikste uitkristalliseer, staan in Matteus 28 : 16 - 20. Heilshistories gesien, is dit die begin van kerklike inlywing van die wat gehoor het hoedat Jesus sy koninkryk proklameer, die evangelie aanvaar en tot bekering kom. Vir die doel van hierdie artikel word hierdie gedeelte ondersoek om te sien hoe die instelling geskied het, wat die plek en betekenis van die Christelike doop is.

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

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


    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.

  12. 全立式压铸机的改造与实践%Transformation and practice of full vertical die casting machine FANG LiGao,ZHOU Quan,ZHANG LiPan

    方立高; 周全; 张丽攀


    Hydraulic circuit and circuit of YTD32-100 type four-column hydraulic machine were redesigned, and it was transformed into the whole vertical die casting machine. Mode -locked oil and injection circuit were independent of the machine. It was convenient to adjust injection pressure, holding pressure time, filling time and other process parameters. The explosion-proof vibrator shell was produced by the machine, and the casting qualified rate reached 90%.%对 YTD32-100型四柱式液压机的液压油路和电路进行了重新设计,将其改造成为全立式压铸机。该机有独立的锁模油路和压射油路,可以方便调节压射比压、保压时间及充型时间等工艺参数。应用该机压铸出了防爆震动器壳体,铸件合格率达到了90%。

  13. 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.

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


    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.

  14. The impact on patient trust of legalising physician aid in dying

    Hall, M; Trachtenberg, F; Dugan, E


    Objective: Little empirical evidence exists to support either side of the ongoing debate over whether legalising physician aid in dying would undermine patient trust. Design: A random national sample of 1117 US adults were asked about their level of agreement with a statement that they would trust their doctor less if "euthanasia were legal [and] doctors were allowed to help patients die". Results: There was disagreement by 58% of the participants, and agreement by only 20% that legalising euthanasia would cause them to trust their personal physician less. The remainder were neutral. These attitudes were the same in men and women, but older people and black people had more agreement that euthanasia would lower trust. However, overall, only 27% of elderly people (age 65+) and 32% of black people thought that physician aid in dying would lower trust. These views differed with physical and mental health, and also with education and income, with those having more of these attributes tending to view physician aid in dying somewhat more favourably. Again, however, overall views in most of these subgroups were positive. Views about the effect of physician aid in dying on trust were significantly correlated with participants' underlying trust in their physicians and their satisfaction with care. In a multivariate regression model, trust, satisfaction, age, and white/black race remained independently significant. Conclusion: Despite the widespread concern that legalising physician aid in dying would seriously threaten or undermine trust in physicians, the weight of the evidence in the USA is to the contrary, although views vary significantly. PMID:16319229

  15. Comparison of environmental impacts of building structures with in situ cast floors and with precast concrete floors

    Lopez-Mesa, Belinda; Pitarch, Angel; Tomas, Ana; Gallego, Teresa [Department of Mechanical Engineering and Construction (ESTCE), Universitat Jaume I, Av. Sos Baynat s/n, Castellon 12071 (Spain)


    In this paper, the environmental impacts of two types of slab systems are studied. The first type, a concrete-based one-way spanning slab, is the most common solution in residential buildings in Spain. The second type, a hollow core slab floor, is increasingly becoming more used in buildings, but is not being broadly used in residential buildings as yet. The study is undertaken through the Life Cycle Analysis methodology, applying the EPS 2000 method. The assessment shows that the environmental impact of a building structure with precast concrete floors is 12.2% lower than that with in situ cast floors for the defined functional unit. (author)

  16. Modernity of parts in casting machines and coefficients of total productive maintenance

    S. Borkowski


    Full Text Available The goal of this study is to investigate the impact of equipment efficiency in casting machines on the quality of die castings made of Al-Si alloys in consideration of their modernity. Analysis focused on two cold-chamber die-casting machines. The assessment of modernity ofthe equipment was made based on ABC analysis of technology and Parker’s scale. Then, the coefficients of total productive maintenance(TPM were employed for assessment of the efficiency of both machines. Using correlation coefficients r allowed authors to demonstrate the relationships between individual TPM coefficients and the number of non-conforming products. The finding of the study is pointing to the differences between the factors which determine the quality of castings resulting from the level of modernity of machines.

  17. Squeeze Casting of Steel Weapon Components


    equipment. The squeeze casting process also differs from rheo- casting.(10-12) Unlike the former, the rheocasting process (8) "Ferrous Die Casting...various phases of rheocasting . At least so far, the process has not been applied to fabrication of complex steel components of the type that are under

  18. Developmental epigenetic programming of caste-specific differences in social insects: an impact on longevity.

    Vaiserman, Alexander


    Social insects are an excellent model system for a deeper understanding of the mechanisms of longevity determination because they have a caste system in which the same genome, due to the differential gene expression, can produce both a short-lived worker and a long-lived queen. For example, in the honeybee, Apis mellifera, queens develop from fertilized eggs that are genetically not different from the eggs that develop into workers. They have, however, a much larger size and specialized anatomy, develop substantially faster and live much longer than worker bees. In many social insects including bees, ants, wasps, and termites, queens and workers show up to a 100-fold difference in lifespan, with reproductive queens having longer longevity than non-reproductive workers. Caste differentiation in social insect species is known to be dependent on the larval nutritional environment. In the honeybee, the caste switching is determined by distinguished feeding of larvae. There is accumulating evidence that queen phenotype is driven by epigenetic mechanisms of gene regulation. Dietary differences during the larval development have been found to lead to differential DNA methylation. This results in caste-biased patterns of gene expression, which, in turn, leads to caste-biased phenotypes, such as short-lived workers and long-lived queens. The investigation of physiological, biochemical and molecular aspects of the biology of queens and workers seems to be a promising way to identifying pathways that control longevity and to developing the treatments designed to influence these pathways.

  19. University students' perspectives on a psychology of death and dying course: exploring motivation to enroll, goals, and impact.

    Buckle, Jennifer L


    This study provides an in-depth investigation of the motivations, goals, and impact on 23 university students enrolled in a Psychology of Death and Dying course. Through a grounded theory analysis of precourse perspective and postcourse reflection assignments, several key themes emerged. Participants were motivated to enroll in the course by their self-identified lack of knowledge on the topic and its professional and personal relevance. They identified three main course goals: cognitive comfort, preparation to support others, and personal growth. At the end of the course, participants noted heightened awareness of personal mortality and increased comfort with death-related topics, as well as reduced fear, surprise at the depth of the thanatology field, and enriched context for their experiences with death and dying. The implications of the results for death educators, researchers, and students are discussed.

  20. Legal physician-assisted dying in Oregon and the Netherlands: evidence concerning the impact on patients in "vulnerable" groups.

    Battin, Margaret P; van der Heide, Agnes; Ganzini, Linda; van der Wal, Gerrit; Onwuteaka-Philipsen, Bregje D


    Debates over legalisation of physician-assisted suicide (PAS) or euthanasia often warn of a "slippery slope", predicting abuse of people in vulnerable groups. To assess this concern, the authors examined data from Oregon and the Netherlands, the two principal jurisdictions in which physician-assisted dying is legal and data have been collected over a substantial period. The data from Oregon (where PAS, now called death under the Oregon Death with Dignity Act, is legal) comprised all annual and cumulative Department of Human Services reports 1998-2006 and three independent studies; the data from the Netherlands (where both PAS and euthanasia are now legal) comprised all four government-commissioned nationwide studies of end-of-life decision making (1990, 1995, 2001 and 2005) and specialised studies. Evidence of any disproportionate impact on 10 groups of potentially vulnerable patients was sought. Rates of assisted dying in Oregon and in the Netherlands showed no evidence of heightened risk for the elderly, women, the uninsured (inapplicable in the Netherlands, where all are insured), people with low educational status, the poor, the physically disabled or chronically ill, minors, people with psychiatric illnesses including depression, or racial or ethnic minorities, compared with background populations. The only group with a heightened risk was people with AIDS. While extralegal cases were not the focus of this study, none have been uncovered in Oregon; among extralegal cases in the Netherlands, there was no evidence of higher rates in vulnerable groups. Where assisted dying is already legal, there is no current evidence for the claim that legalised PAS or euthanasia will have disproportionate impact on patients in vulnerable groups. Those who received physician-assisted dying in the jurisdictions studied appeared to enjoy comparative social, economic, educational, professional and other privileges.

  1. HLA-B27 allele diversity in Indians: impact of ethnic origin and the caste system.

    Shankarkumar, U


    HLA-B27 is a serological specificity which encompasses an increasing number of subtypes that show varied racial/ethnic prevalence in the world. Here, data from 5129 Indians (4500 population and caste; 629 tribal) is compiled from the literature. In addition, HLA-B27 subtyping of 58 positive individuals from Maharastra is presented. Analysis revealed an increased B27 antigen frequency among the north Indian groups (>5%) compared to the south Indian groups (caste and tribal groups studied. The study showed that more extensive subtyping in other Indian caste groups will be necessary to resolve the evolutionary implications of HLA-B27 subtypes and their relationship to disease association in the Indian context.

  2. Die topkwark

    R. Tegen


    Full Text Available ’n Oorsig van die belangrikheid van die onlangs ontdekte topkwark by Fermilab in Chicago word gegee. Daar word aangetnon dat die topkwark belangrik is in fisika van die Oerknal, oftewel "Big Bang", en in die Standaard Model van Elementêredeeltjie-fisika. Toepaslike literatuur vir verdere studie kan van die lys van verwysings in hierdie kort, nietegniese artikel, nagegaan word.

  3. Effects of selected casting methods on mechanical behaviour of Al-Mg-Si alloy

    Henry Kayode TALABI


    Full Text Available This study investigated the effects of selected casting methods on mechanical behaviour of Al-Mg-Si alloy. The casting methods used was spin, sand and die casting, these were done with a view to determine which of the casting methods will produce the best properties. The pure aluminium scrap, magnesium and silicon were subjected to chemical analysis using spectrometric analyzer, thereafter the charge calculation to determine the amount needed to be charged into the furnace was properly worked out and charged into the crucible furnace from which as-cast aluminium was obtained. The mechanical properties of the casting produced were assessed by hardness and impact toughness test. The optical microscopy and experimental density and porosity were also investigated. From the results it was observed that magnesium and silicon were well dispersed in aluminium matrix of the spin casting. It was observed from visual examination after machining that there were minimal defects. It was also observed that out of the three casting methods, spin casting possesses the best mechanical properties (hardness and impact toughness.

  4. Impact of vegetation die-off on spatial flow patterns over a tidal marsh

    Temmerman, Stijn; Moonen, Pieter; Schoelynck, Jonas; Govers, Gerard; Bouma, Tjeerd J.


    Large-scale die-off of tidal marsh vegetation, caused by global change, is expected to change flow patterns over tidal wetlands, and hence to affect valuable wetland functions such as reduction of shoreline erosion, attenuation of storm surges, and sedimentation in response to sea level rise. This study quantified for the first time the effects of large-scale (4 ha) artificial vegetation removal, as proxy of die-off, on the spatial flow patterns through a tidal marsh channel and over the surrounding marsh platform. After vegetation removal, the flow velocities measured on the platform increased by a factor of 2 to 4, while the channel flow velocities decreased by almost a factor of 3. This was associated with a change in flow directions on the platform, from perpendicular to the channel edges when vegetation was present, to a tendency of more parallel flow to the channel edges when vegetation was absent. Comparison with hydrodynamic model simulations explains that the vegetation-induced friction causes both flow reduction on the vegetated platform and flow acceleration towards the non-vegetated channels. Our findings imply that large-scale vegetation die-off would not only result in decreased platform sedimentation rates, but also in sediment infilling of the channels, which together would lead to further worsening of plant growth conditions and a potentially runaway feedback to permanent vegetation loss.

  5. Impact of the foliar pathogen Swiss needle cast on wood quality of Douglas-fir.

    G.R. Johnson; Amy T. Grotta; Barbara L. Gartner; Geoff. Downes


    Many stands of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) near coastal areas of Oregon and Washington are heavily infected with the foliar pathogen causing Swiss needle cast (SNC) disease, and yet there is very little research on the resulting wood quality. Modulus of elasticity(MOE), modulus of rupture (MOR), microfibril angle (MFA), wood...

  6. 大口径厚壁钢管热模法离心铸造机的设计与应用%Design and Application of A Centrifugal Casting Machine with Hot Die for Large Caliber Steel Pipt with Thick Wall



    详细介绍了采用热模法离心铸造厚壁钢管坯的设计思路,以及该机主要机构(等量浇注装置、主机、推管机构等)的设计.%Design idea of a centrifugal casting machine with hot die for large caliber steel pipt with thick wall has been introduced in details with design of the main equipment such as pouring device with dosing device, main machine and pipe ejector etc., hence a typical instance of application of centrifugal casting technology on forming of pipe with thick wall.

  7. Impact of arbitrary and mean transfer of dental casts to the articulator on centric occlusal errors.

    Morneburg, Thomas R; Pröschel, Peter A


    When fabricating dental restorations, casts are usually transferred to the articulator based on arbitrary hinge axes or mean values instead of true hinge axis points. Using arbitrary hinge axis points or mean values can lead to occlusal errors if the vertical relation is changed in the articulator (e.g., when a centric record is used). This study predicted the probability of occlusal errors occurring in a group of subjects when casts are mounted based on arbitrary hinge axis points or mean values. In 57 healthy volunteers, true hinge axis points, arbitrary hinge axis points, right infraorbital point, maxillary incisal point, and the palatal cusps of the second molars were determined. Mean hinge axis points were established based on Balkwill angles between 17° and 25°. Occlusal errors evoked by cast mounting in relation to arbitrary or mean axes compared to true hinge axes were calculated. Errors were determined for vertical relation settings of 2 and 4 mm. With 2 mm vertical relation, occlusal errors ≥340 µm occurred with a 10% probability with arbitrary hinge axis mounting. At the same probability level, the error increased moderately to ≥440 µm with mean value mounting and a Balkwill angle of 17°. With a Balkwill angle of 25° occlusal errors ≥1,120 µm occurred with 10% probability. Occlusal errors increased considerably with a vertical relation setting of 4 mm. If vertical relation shall be altered, a transfer of the casts according to arbitrary hinge axes is recommended. If casts are transferred according to mean values, errors are bigger depending on the articulator used.

  8. Clean Metal Casting

    Makhlouf M. Makhlouf; Diran Apelian


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

  9. The impact of nuclear imaging on pediatric urology; Die Bedeutung nuklearmedizinischer Untersuchungsverfahren in der Kinderurologie

    Zoeller, G. [Urologische Universitaetsklinik, Goettingen (Germany)


    Nuclear imaging has a key role in diagnosis and therapy in modern pediatric urology. We discuss the value and limitations of radionuclide studies (diuresis renogramm, DMSA, VCUG, MIBG scintigraphy) with special regard to characteristic pathologic entities in pediatric urology. (orig.) [German] Nuklearmedizinische Untersuchungsverfahren nehmen in der modernen Kinderurologie eine zentrale Stellung in der Diagnostik und Therapieplanung ein. In einer Uebersicht werden die Wertigkeit der verschiedenen Untersuchungsverfahren (Diureserenographie, DMSA, Isotopen-MCU, MIBG-Szintigraphie) bei typischen kinderurologischen Krankheitsbildern dargestellt und ihre Grenzen aufgezeigt. (orig.)

  10. Comparison of marginal accuracy of castings fabricated by conventional casting technique and accelerated casting technique: An in vitro study

    S Srikanth Reddy


    Full Text Available Background: Conventional casting technique is time consuming when compared to accelerated casting technique. In this study, marginal accuracy of castings fabricated using accelerated and conventional casting technique was compared. Materials and Methods: 20 wax patterns were fabricated and the marginal discrepancy between the die and patterns were measured using Optical stereomicroscope. Ten wax patterns were used for Conventional casting and the rest for Accelerated casting. A Nickel-Chromium alloy was used for the casting. The castings were measured for marginal discrepancies and compared. Results: Castings fabricated using Conventional casting technique showed less vertical marginal discrepancy than the castings fabricated by Accelerated casting technique. The values were statistically highly significant. Conclusion: Conventional casting technique produced better marginal accuracy when compared to Accelerated casting. The vertical marginal discrepancy produced by the Accelerated casting technique was well within the maximum clinical tolerance limits. Clinical Implication: Accelerated casting technique can be used to save lab time to fabricate clinical crowns with acceptable vertical marginal discrepancy.

  11. Advanced casting technologies for lightweight automotive applications

    Alan A. Luo


    Full Text Available This paper provides an overview of alloy and process developments in aluminum and magnesium castings for lightweight automotive applications. Wear-resistant aluminum alloys, creep-resistant and high strength/ductility magnesium alloys have been developed for automotive applications. On the process front, vacuum-assisted die casting and high vacuum die casting technologies have been developed for high-integrity body and chassis applications. Thin-wall and hollow casting components are being produced by low-pressure die casting processes for structural applications. Overcasting technology is gaining traction and has enabled mixed material designs for automotive sub-systems such as engine cradles and instrument panel beams. Simulation tools developed to predict the interfacial interactions of the dissimilar components and the structural integrity of the overcast systems are being validated in the casting trials.

  12. Continuous squeeze casting process by mass production

    Yun Xia; Rich Jacques


    Squeeze casting has become the most competitive casting process in the automotive industry because of its many advantages over high pressure die casting (HPDC). Many squeeze casting R & D and small amount volume making have been implemented around the world, but the mass production control still exists problem. SPX Contech squeeze casting process P2000 successfully achieved the goal of mass production; it includes lower metal turbulence, less gas entrapment, minimum volumetric shrinkage, and thus less porosity. Like other casting processes, however, the quality of squeeze castings is still sensitive to process control and gate and runner design. Casting defects can form in both die-filling and metal solidification phases. The occurrence of casting defects is directly attributed to improper adjustment or lack of control of process parameters including metal filling velocity, temperature, dwell time, cooling pattern, casting design, and etc. This paper presents examples using P2000 techniques to improve part quality in the following areas: runner & gate design, casting & runner layout in the die, squeeze pin application, high thermal conductivityinserts, cooling/heating systems, spray & lubricant techniques,and part stress calculation from shrinkage or displacement prediction after stress relief.

  13. Die menswaardigheid van die menslike embrio : die debat tot dusver

    Vorster, J.M


    ...), "Stem cell research: the ethical issues". Rakende die gebruik van menslike embrio's in stamselnavorsing, behandel hierdie artikels die potensiaal van die menslike embrio, die morele status (menswaardigheid...

  14. Studi Eksperimental Pengaruh Model Sistem Saluran Dan Variasi Temperatur Tuang Terhadap Prosentase Porositas, Kekerasan Dan Harga Impact Pada Pengecoran Adc 12 Dengan Metode Lost Foam Casting

    Restu Yanuar Salam


    Full Text Available Metode pengecoran lost foam merupakan metode yang tergolong baru dalam industri pengecoran logam. Pada saat ini belum banyak industri pengecoran logam yang menggunakan metode ini dalam memproduksi benda cor. Sedikitnya industri yang menerapkan metode pengecoran ini, yang mendorong untuk melakukan percobaan pengecoran dengan menggunakan metode lost foam, dengan melakukan perbedaan variasi temperatur tuang dan variasi model sistem saluran. Proses pengecoran dengan metode lost foam ini menggunakan styrofoam sebagai polanya, yang ditanam dalam cetakan yang berisi pasir silika kering (tanpa pengikat kemudian cetakan digetarkan untuk memadatkan pasir. Ketika logam cair dimasukkan ke dalam cetakan, maka styrofoam akan menguap sampai cetakan tersebut terisi penuh oleh logam cair. Dalam penelitian ini, parameter yang digunakan adalah model sistem saluran dan variasi temperatur tuang terhadap kualitas hasil coran, diantaranya kekerasan, harga impact, prosentase porositas dan struktur mikro. Material yang digunakan dalam pengecoran ini adalah ADC (Aluminium Die Casting 12. Parameter pertama yaitu model sistem saluran meliputi saluran samping, saluran bawah, saluran bawah dengan 2 gate dan saluran bawah dengan 3 gate dengan temperatur tuang konstan 700°C. Parameter kedua yaitu variasi perbedaan temperatur tuang antara 700°C, 750°C, 800°C dan 850°C dengan sistem saluran samping. Dari hasil penelitian ini diperoleh bahwa sistem saluran samping memiliki prosentase cacat porositas paling sedikit dibanding sistem saluran lainnya yaitu sebesar 2,7535% dan memiliki harga impact rata-rata paling besar yaitu 0,0275 J/mm2 pada potongan 1 dan 0,0660 J/mm2 pada potongan 2. Variasi temperatur tuang berpengaruh terhadap banyaknya cacat porositas dan harga impact rata-rata. Temperatur tuang 700°C dibanding temperatur tuang yang lain memiliki cacat porositas paling sedikit dan harga impact rata-rata paling besar yaitu 0,0275 J/mm2 pada potongan 1 dan 0,0660 J/mm2

  15. Formation Regularity of Pores During Laser Welding of Die-Cast Magnesium Alloys and Its Mechanism%压铸镁合金激光焊气孔形成规律及原因

    张婧; 单际国; 温鹏; 任家烈


    由于母材含有大量气源,气孔是压铸镁合金激光焊最主要的问题.在不同的激光功率密度下,采用不同的热输入对压铸镁合金激光焊气孔形成规律进行了研究.在低激光功率密度(1.6×10W/cm以下)焊接时,随着热输入的升高气孔率持续升高;在高激光功率密度(3.2×10W/cm以上)焊接时,在一定热输入下气孔率出现极小值,由此增加或减少热输入都会造成气孔率的升高,但当热输入非常低时气孔率又出现降低的趋势,即不同激光功率密度下气孔率随焊接热输入的变化存在两种不同的规律.结合压铸镁合金母材中气源行为以及焊接热过程,对两种规律的形成原因进行了讨论和实验验证,研究发现获得低气孔率焊缝的关键是抑制压铸镁合金中原子氢的析出,使其以固溶形式继续存在于焊缝中.%Welding pore is the main problem during laser welding of die-cast magnesium alloys. The influences of laser power density and heat input on pore formation regularity during laser welding of die-cast magnesium alloys are studied. The formation regularities of pore are different under low and high laser power densities. Under low laser power densities (less than 1.6 × l06 W/cm2 ), porosity increases with the increase of weld heat input; under high power densities(more than 3.2 × l06 W/cm2 ), the minimum value of porosity can be obtained at certain weld heat input, and changing weld heat input a bit higher or lower than this certain value both increase porosity, but when the weld heat input is low enough, low porosity can be obtained. The different regularities can be attributed to the influences of laser power density and weld heat input on welding thermal process and the behaviors of gas sources in weld pool. It is found that suppressing the atomic hydrogen precipitation is the key of obtaining low porosity welds.

  16. 刷镀工艺在铝合金压铸件磨损后修复中的应用研究%Application of brush plating in repair of abraded aluminum alloy die-castings

    张玉峰; 李云彪


    In view of the defects in brush plating of aluminum alloy such as poor adhesion, easily cracked or peeled, a new brush plating proces for aluminum and its alloys was advanced. Formula and operating conditions of the procedures were described, high-packed alkaline copper deposit was adopted to act as interlayer and fast nickel brush deposit as working layer. Adhesion and wear resistance of the brush deposits were tested according to GB2933-86. Results show that the process improves the adhesion and wear resistance of brush deposits, and extends the service life of brush plated articles, which is applicable to the repair of abraded aluminum alloy die castings.%鉴于铝合金刷镀层结合力差,易产生裂纹及剥落现象。本文提出了一种新的铝及其合金刷镀工艺。阐述了各工艺步骤的配方及操作条件。过渡层采用高堆积碱铜,工作层为快速刷镀镍。根据GB2933-86测试镀层结合力及耐磨性。结果表明:该工艺可提高刷镀层的结合力和耐磨性,延长零件使用寿命。适用于铝合金压铸件磨损后的修复。

  17. Effect of cast steel production metallurgy on the emergence of casting defects

    L. Čamek


    Full Text Available The paper documents metallurgical possibilities of high alloy cast steel production in open induction medium frequency furnaces and an electric arc furnace in a gravity die casting foundry. The observation was focused on the emergence of gas defects in steel castings. The content of gases achieved during the metallurgical processes was evaluated for every unit of the production equipment and the casting ladle before casting into disposable sand moulds. The sand mould area was considered to be constant. The aim was to evaluate the current metallurgical possibilities of affecting the content of gases in high alloy cast steel in the current technical conditions of the foundry.

  18. Deformation mechanism at impact test of Al-11% Si alloy processed by equal-channel angular pressing with rotary die



    Al-11%Si (mass fraction) alloy was transformed into a ductile material by equal-channel angular pressing (ECAP) with a rotary die. Two mechanisms at impact test, slip deformation by dislocation motion and grain boundary sliding, were discussed. The ultrafine grains with modified grain boundaries and the high content of fine particles (<1 μm) were necessary for attaining high absorbed energy. The results contradict the condition of slip deformation by dislocation motion and coincide with that of grain boundary sliding. Many fine zigzag lines like a mosaic were observed on the side surface of the tested specimens. These observed lines may show grain boundaries appeared by the sliding of grains.

  19. Effects of Zr, Ti, and Al Additions on Nonmetallic Inclusions and Impact Toughness of Cast Low-Alloy Steel

    Bizyukov, Pavel V.; Giese, Scott R.


    A microalloying of the low-carbon and low-alloy cast steel was conducted with Zr, Ti, and Al that were added to the steel in four combinations. After heat treatment, the samples were tested for impact toughness at room temperature using the Charpy method. The highest values of impact toughness were obtained in the group treated with Zr, while Zr-Ti and Zr-Ti-Al groups showed moderate toughness values; the lowest values were observed in the Zr-Al group. Difference among the treatment groups was observed in the fracture mechanisms, morphology, and area distribution of the inclusions. High toughness values achieved in the trials treated with zirconium corresponded with smooth ductile fracture. The metal treated with a combination of zirconium and titanium had a relatively small area occupied by inclusions, but its toughness was also moderate. Lowest impact toughness values corresponded with the larger area occupied by the inclusions in the trials treated with aluminum. Also, a connection between the solubility product [Al][N] and impact toughness was established. The study also provides a qualitative description and quantitative analysis of the nonmetallic inclusions formation as a result of microalloying treatment. The precipitation sequence of the inclusions was described based on the thermochemical calculations for the nonmetallic compounds discovered in the experimental steel. A description of the size distribution, morphology, and composition was conducted for the oxides, nitrides, sulfides, and multiphase particles.

  20. Numerical optimization of die geometry in open die forging

    Christiansen, Peter; Hattel, Jesper Henri; Bay, Niels


    This paper deals with numerical optimization of open die forging of large metallic ingots made by casting implying risk of defects, e.g. central pores. Different material hardening properties and die geometries are combined in order to investigate, which geometry gives rise to maximum closure...... of a centreline hole in a single compression operation. Friction is also taken into account. The numerical analysis indicates that a lower die angle of approximately 140o results in the largest centreline hole closure for a wide range of material hardening. The value of optimum die angle is not influenced...... by friction, which was found only to change the degree of centreline porosity closure in case of small lower die angle....

  1. Qualitative Reasoning for Additional Die Casting Applications

    R. Allen Miller; Dehua Cui; Yuming Ma


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

  2. Die posisie van die Helper in die sending

    I. J. van der Walt


    Full Text Available Gedurende die aanvangsjare van die sending het die helper ’n onmisbare funksie vervul. Hulle het die onherbergsame binnelande geken, waardevolle kontakpunte vir die sendelinge geopen en hulle mense geestelik help voorlig en voorberei.

  3. 薄壁铝合金压铸充型过程中铸件与铸型界面的换热行为%Heat transfer behaviors between metal and die during filling process of thin-wall aluminum alloy under high pressure die casting conditions

    朱必武; 李落星; 刘筱; 张立强; 徐戎; 卜晓兵


    The thin-wall AlSi10MnMg aluminum alloy samples were prepared by high pressure die casting. The motion laws of press-shoot ram were recorded by a high speed camera system and the heat transfer coefficients between the casting and mold were calculated by the energy conservation equation. Therefore, the effects of different heat transfer coefficients on the simulated filling results were discussed. The results show that the filling fluidity length increases with the pouring temperature increasing;when the filling process is above the liquidus, the filling time and the heat transfer coefficient increase with the pouring temperature increasing. However, when the filling process is below the liquidus, the changes of the filling time and the heat transfer coefficient are insignificant. The simulations using the heat transfer coefficient which is calculated by the energy conservation equation are well consistent with the experimental results.%采用压铸制备薄壁AlSi10MnMg铝合金铸件,用高速摄像技术记录分析压铸压射冲头的运动规律,并通过热平衡方程求解充型过程中铸件熔体和铸型之间的换热系数,最后通过数值模拟的方法讨论采用不同换热系数对充型仿真结果的影响。结果表明:充型流动长度随浇注温度的升高而增长;当充型处于液相线温度之上时,充型时间、换热系数随浇注温度的升高而增长;当充型至温度处于液相线温度以下时,充型时间和换热系数变化都很小。模拟仿真结果显示,采用基于热平衡方程求得的换热系数的计算模拟仿真结果与实验结果较一致。

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

    David Schwam; John F. Wallace; Quanyou Zhou


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

  5. Imaging techniques and their impact in treatment management of patients with acute flank pain; Die bildgebenden Verfahren und ihre Rolle beim Behandlungsmanagement von Patienten mit akutem Flankenschmerz

    Grosse, A.; Grosse, C.A.; Heinz-Peer, G. [Klinik fuer Radiodiagnostik der Medizinischen Universitaet Wien (Austria); Mauermann, J. [Medizinische Universitaet Wien (Austria). Klinik fuer Urologie


    The purpose of this overview is to provide a general summary of the imaging techniques applied at the Vienna Hospital for the investigation of acute flank pain and the diagnosis of stone disease and the evaluation of their efficacy and impact on therapy management. The number of publications on the issue of ''intravenous urography (IVU) vs computed tomography (CT)'' is abundant; in recent years, advocates of CT make up the majority. In the Department of Urology at the Vienna Hospital, conventional techniques such as ultrasound and IVU besides UHCT still play an important role. This overview presents the advantages and disadvantages of the various imaging techniques for diagnosis of stone disease and evaluates their significance regarding therapy management of patients with acute flank pain. (orig.) [German] Ziele der Uebersichtsarbeit sind eine zusammenfassende Darstellung der an der Universitaetsklinik fuer Urologie in Wien angewendeten Untersuchungstechniken zur Abklaerung von akutem Flankenschmerz bzw. zur Diagnostik des Steinleidens und die Bewertung ihrer Effizienz und Bedeutung im Therapiemanagement. Die Literatur zum Thema ''intravenoese Urographie (IVU) vs. Computertomographie (CT)'' zur Diagnostik der Urolithiasis bzw. Nephrolithiasis ist reichhaltig. In den letzten Jahren ueberwiegen zunehmend die Befuerworter der CT. An der Universitaetsklinik fuer Urologie in Wien kommen neben der nativen CT weiterhin konventionelle Verfahren wie die Sonographie und die IVU haeufig zum Einsatz. In dieser Arbeit werden die Vorzuege und Nachteile der verschiedenen bildgebenden Verfahren in der Steindiagnostik aufgezeigt und ihr Stellenwert beim therapeutischen Management von Patienten mit akutem Flankenschmerz evaluiert. (orig.)

  6. Oxygen segregation and its impact on the absorption of hydrogen in vanadium; Einfluss der Sauerstoffsegregation auf die Absorption von Wasserstoff in Vanadium

    Paulus, H.; Lammers, M. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany); Mueller, K.H. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany)]|[Paderborn Univ. (Gesamthochschule), Soest (Germany). Fachbereich 16 - Elektrische Energietechnik; Kiss, G.; Kemeny, Z. [Technical Univ. Budapest (Hungary)


    The impact of the dissolved oxygen on the hydrogen absorption in vanadium was analysed with an UHV apparatus. The vanadium specimen with an oxygen content of 230 ppm was treated by a variety of heat treatments. The depth distributions of the induced concentrations of segregated oxygen in the specimen were analysed by SIMS. It was found that the amount of segregated oxygen increases with rising final temperature and tempering period. In a further experiment, the specimen was exposed after each segregation process to a H{sub 2}-pressure of 2.2 x 10{sup -4} Pa for a period of 1800 sec. The hydrogen amounts absorbed in the specimen were determined by thermal desorption mass spectrometry (TDMS). It was found that segregation of oxygen close to the surface of the specimen likewise hampers the absorption of hydrogen. (orig./CB) [Deutsch] Der Einfluss des im Volumen geloesten Sauerstoffs auf die Wasserstoff-Absorption in Vanadium wurde in einer UHV-Apparatur untersucht. Zunaechst wurde die V-Probe mit einem Sauerstoffgehalt von 230 ppm unterschiedlichen thermischen Behandlungen ausgesetzt. Die sich einstellenden Konzentrationstiefenverteilungen des an der Oberflaeche segregierten Sauerstoffs wurden anschliessend mit SIMS untersucht. Dabei nimmt die Menge des segregierten Sauerstoffs mit der Hoehe der Endtemperatur sowie der Temperzeit zu. In einem weiteren Experiment wurde die Probe nach jeder Segregationsprozedur fuer eine Zeit von 1800 sec einem H{sub 2}-Druck von 2.2 x 10{sup -4} Pa ausgesetzt. Die Mengen des dabei aufgenommenen Wasserstoffs wurden mit Hilfe der thermischen Desorptions-Massenspektrometrie TDMS bestimmt. Dabei zeigt sich, dass auch die Segregation von Sauerstoff im oberflaechennahen Bereich die Wasserstoffaufnahme in Vanadium behindert. (orig.)

  7. 混合稀土对压铸AZ91D合金的组织及力学性能的影响%Effects of Mischmetal on Mechanical Properties and Microstructure of Die Casting Magnesium Alloy AZ91D Magnesium Alloy

    徐玉磊; 张奎; 李兴刚; 雷健


    研究了不同添加量的混合稀土对压铸AZ91D合金的组织和力学性能的影响.添加混合稀土后,常温力学性能没有明显改善.在100℃时,混合稀土含量为0.4%的压铸AZ91D合金的力学性能与不含混合稀土的试样几乎相等.在170℃时,混合稀土含量为0.4%的压铸AZ91D合金的抗拉强度、屈服强度及伸长率分别为206 MPa、142 MPa、26%,比不含混合稀土的压铸AZ91D试样的力学性能分别提高15.7%、10%及30%.这是因为添加适量的混合稀土后,形成热稳定性较高的强化相,增加了位错滑移阻力并阻碍裂纹扩展,镁基体中稀土元素起到固溶强化作用,从而提高镁合金的高温抗拉强度.%Effects of the mischmetal addition in range of 0. 4%~1. 7% on the microstructure mechanical properties of die casting AZ91D alloy were investigated to improve the elevated tempurature mechanical properties of the alloy. The results reveal that ambient tempurature mechanical properties of the alloy are almost independent of the mischmetal addition. Mechanical properties of the die casting AZ91D alloy with 0.4% mischmetal addition at 100℃ are near to those of the alloy at room temperature. Tensile strength, yield strength and elongation of the die casting AZ91D-0. 4MM at 170 ℃ reach 206 Mpa, 142 Mpa and 26% , respectively, increased by 15. 7% , 10% , and 30% , respectively, compared with those of die casting AZ91D alloy without MM addition, which is attributed to the formation of strengthening phase with high thermal stability due to the addition of proper MM increasing the dislocation sliding restrain the propagation of crack as well as the solid solution strengthening effects in the magnesium matrix.

  8. Rapid die manufacturing using direct laser metal deposition

    Pereira, MFVT


    Full Text Available This paper highlights the work undertaken at the CSIR on the issue of rapid die manufacturing through the application and evaluation of a rapid prototyping technique and coating technologies applied to die components of a high pressure casting die...

  9. Effect of melt treatment on microstructure and impact properties of Al–7Si and Al–7Si–2.5Cu cast alloys

    K G Basavakumar; P G Mukunda; M Chakraborty


    The microstructures and impact toughness of Al–7Si and Al–7Si–2.5Cu cast alloys were studied after various melt treatments like grain refinement and modification. The results indicate that combined grain refined and modified Al–7Si–2.5Cu alloys have microstructures consisting of uniformly distributed -Al grains, interdendritic network of fine eutectic silicon and fine CuAl2 particles in the interdendritic region. These alloys exhibited improved impact toughness in as cast condition when compared to those treated by individual addition of grain refiner or modifier. The improved impact toughness of Al–7Si–2.5Cu alloys are related to breakage of the large aluminum grains and uniform distribution of eutectic silicon and fine CuAl2 particles in the interdendritic region resulting from combined refinement and modification. This paper attempts to investigate the influence of microstructural changes in the Al–7Si and Al–7Si–2.5Cu cast alloys by grain refinement, modification and combined action of both on the impact toughness.

  10. Impact of sea-level rise in a Mediteranean delta: The Ebro delta cast

    Sánchez-Arcilla, A.; Stive, M.D.F.; Jiménez, J.A.; García, M.A.


    In anticipation of a comprehensive, multidisciplinary study on the impact of climatic change on the Ebro Delta preliminary results are here presented of the response of the outer delta coast to present and future relative sea-level rise. Due to the absence of observations and predictions of regional

  11. Impact of sea-level rise in a Mediteranean delta: The Ebro delta cast

    Sánchez-Arcilla, A.; Stive, M.D.F.; Jiménez, J.A.; García, M.A.


    In anticipation of a comprehensive, multidisciplinary study on the impact of climatic change on the Ebro Delta preliminary results are here presented of the response of the outer delta coast to present and future relative sea-level rise. Due to the absence of observations and predictions of regional

  12. Caste System

    Hoff, Karla


    In standard economics, individuals are rational actors and economic forces undermine institutions that impose large inefficiencies. The persistence of the caste system is evidence of the need for psychologically more realistic models of decision-making in economics. The caste system divides South Asian society into hereditary groups whose lowest ranks are represented as innately polluted. ...

  13. The impact of a palliative care educational component on attitudes toward care of the dying in undergraduate nursing students.

    Mallory, Judy L


    Nurse educators have identified that historically nurses have not been prepared to care for dying patients. Research also has identified that nursing students have anxieties about death, dying, and caring for dying patients. Several factors have been identified as affecting nurses' and nursing students' attitudes toward care of the dying. Factors addressed in this research were current and previous death education. This research incorporated experiential learning using a model of death education and transformative learning theory. The educational experiences were geared to help students understand the skills needed to care competently and compassionately for the dying. The use of the End of Life Nursing Education Consortium (ELNEC) education package along with experiences at the hospice, the funeral home, the anatomy laboratory, and role play helped facilitate transformative learning in the nursing students. The study examined the effects of an educational experience to determine if a one-time educational experience provides sufficient, lasting effects in a 6-week format. Results of this study indicate that education can have a positive effect on nursing students' attitudes toward care of the dying. Nursing students in the intervention group had a significant positive increase in their attitudes toward care of the dying after the intervention. The attitude change increased slightly after a 4-week period.

  14. Cast iron - a predictable material

    Jorg C. Sturm


    Full Text Available High strength compacted graphite iron (CGI or alloyed cast iron components are substituting previously used non-ferrous castings in automotive power train applications. The mechanical engineering industry has recognized the value in substituting forged or welded structures with stiff and light-weight cast iron castings. New products such as wind turbines have opened new markets for an entire suite of highly reliable ductile iron cast components. During the last 20 years, casting process simulation has developed from predicting hot spots and solidification to an integral assessment tool for foundries for the entire manufacturing route of castings. The support of the feeding related layout of the casting is still one of the most important duties for casting process simulation. Depending on the alloy poured, different feeding behaviors and self-feeding capabilities need to be considered to provide a defect free casting. Therefore, it is not enough to base the prediction of shrinkage defects solely on hot spots derived from temperature fields. To be able to quantitatively predict these defects, solidification simulation had to be combined with density and mass transport calculations, in order to evaluate the impact of the solidification morphology on the feeding behavior as well as to consider alloy dependent feeding ranges. For cast iron foundries, the use of casting process simulation has become an important instrument to predict the robustness and reliability of their processes, especially since the influence of alloying elements, melting practice and metallurgy need to be considered to quantify the special shrinkage and solidification behavior of cast iron. This allows the prediction of local structures, phases and ultimately the local mechanical properties of cast irons, to asses casting quality in the foundry but also to make use of this quantitative information during design of the casting. Casting quality issues related to thermally driven

  15. Die regsposisie van die gemolesteerde kind 1

    P.J. Schabort


    Full Text Available Hoe reik die reg uit na die seksueel gemolesteerde kind? As na die reg in wye verband gekyk word, sou dit alie wetgewing en alle gemeneregsbeginsels en alle regsprosedures insluit waardeur die Staat poog om molestering te voorkom en die gemolesteerde kind in beskerming te neem. Dit le baie wyd en sou byvoorbeeld die maatreels insluit van die Kindenvet 33 van 1960; die Wet op Egskeiding 70 van 1979; die Wet op Kindersorg 74 van 1983; die Wet op die Status van Kinders 82 van 1987 en die Wet op Bemiddeling in Sekere Egskeidingsaangeleenthede 24 van 1987. Eersdaags sal dit moontlik ook ’n Manifes vir die Regte van Kinders insluit wat vermoedelik geskoei sal wees op die W O se Konvensie vir die Regte van die Kind (1989 w a arv an die RSA tan s nog nie ’n ondertekenaar is nie.

  16. Effect of iron-intermetallics and porosity on tensile and impact properties of aluminum-silicon-copper and aluminum-silicon-magnesium cast alloys

    Ma, Zheyuan

    Aluminum-silicon (Al-Si) alloys are an important class of materials that constitute the majority of aluminum cast parts produced, due to their superior properties and excellent casting characteristics. Within this family of alloys, Al-Si-Cu and Al-Si-Mg cast alloys are frequently employed in automotive applications. The commercially popular 319 and 356 alloys, representing these two alloy systems, were selected for study in the present work, with the aim of investigating the effect of iron intermetallics and porosity on the alloy performance. This was carried out through a study of the tensile and impact properties, these being two of the important mechanical properties used in design calculations. Iron, through the precipitation of second phase intermetallic constituents, in particular the platelike beta-Al5FeSi phase, is harmful to the alloy properties. Likewise, gas- or shrinkage porosity in castings is also detrimental to the mechanical properties. By determining the optimum alloying, melt processing and solidification parameters (viz., Fe content, Sr modification and cooling rate) required to minimize the harmful effects of porosity and iron intermetallics, and studying their role on the fracture behavior, the fracture mechanism in the alloys could be determined. Castings were prepared from both industrial and experimental 319.2, B319.2 and A356.2 alloy melts, containing Fe levels of 0.2--1.0 wt%. Sr-modified (˜200 ppm) melts were also prepared for each alloy Fe level. The end-chilled refractory mold used provided directional solidification and a range of cooling rates (or dendrite arm spacings, DAS) within the same casting. Tensile and impact test samples machined from specimen blanks sectioned from the castings at various heights above the chill end provided DASs of 23--85mum. All samples were T6-heat-treated before testing. Tests were carried out employing Instron Universal and Instrumented Charpy testing machines. Optical microscopy, image analysis, SEM

  17. Expert Network for Die Casing Defect Analysis

    Jiadi WANG; Yongfeng JIANG; Chen LU; Wenjiang DING


    Due to the competition and high cost associated with die casting defects, it is urgent to adopt a rapid and effective method for defect analysis. In this research, a novel expert network approach was proposed to avoid some disadvantages of rulebased expert system. The main objective of the system is to assist die casting engineer in identifying defect, determining the probable causes of defect and proposing remedies to eliminate the defect. 14 common die casting defects could be identified quickly by expert system on the basis of their characteristics. BP neural network in combination with expert system was applied to map the complex relationship between causes and defects, and further explained the cause determination process.Cause determination gives due consideration to practical process conditions. Finally, corrective measures were recommended to eliminate the defect and implemented in the sequence of difficulty.

  18. Die Heimkunft

    Stephen Romer


    Full Text Available En hommage amical à René Gallet.Die HeimkunftRuhig glänzen indes die silberen Höhen darüber,Voll mit Rosen ist schon droben der leuchtende Schnee.- HölderlinAnd then one day the young master returnsfrom a dark placeand birdsong leads the wanderer inand the cat yawns and curls againin the headiness of this instantthe house is fragrantwith woodsmoke and honeysucklewhich is a kind of accomplishment.Returning from dogmahome to the humanehe lays asideknapsack, alpenstock and hat,goes straight to t...

  19. 变速箱壳体消失模铸造工艺与缺陷防止%The Process and Defects of the Die Casting of the Gearbox Shell



    本文首先就消失模铸造工艺进行简要介绍,分析消失模铸造工艺在变速箱壳体中应用的缺陷,并提出解决缺陷的有效措施。%This paper briefly introduces the process of the lost foam casting process, analyzes the defects in the application of the lost foam casting technology in the application of variable speed box.

  20. Hair casts

    Sweta S Parmar


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

  1. Developing technological process of obtaining giality casts

    A. Issagulov


    Full Text Available The article considers the process of manufacturing castings using sand-resin forms and alloying furnace. Were the optimal technological parameters of manufacturing shell molds for the manufacture of castings of heating equipment. Using the same upon receipt of castings by casting in shell molds furnace alloying and deoxidation of the metal will provide consumers with quality products and have a positive impact on the economy in general engineering.

  2. Impact strength of GX8CrNi12, GX5CrNi18-9 and GX5CrNiMo19-11-2 cast steel at - 30 °C

    B. Kalandyk


    Full Text Available The results of impact tests carried out at - 30 °C on cast alloyed GX8CrNi12, GX5CrNi18-9 and GX5CrNiMo19-11-2 steel grades are reported. It has been shown that at - 30 °C, the addition of 1 % Ni to cast GX8CrNi12 steel does not provide the required impact strength of 35 J/cm2. In contrast, other tested materials containing 8 ÷ 9 % Ni can easily reach exceeding 50 J/cm2. Numerous non-metallic inclusions present in the microstructure of cast GX5CrNi-Mo19-11-2 steel resulting from, among others, the miscalculated refining process were found to be one of the main causes of reduced impact strength as compared to the cast GX5CrNi18-9 steel.

  3. Calvyn en die Skrifgesag

    L. F. Schulze


    Full Text Available Die probleem van die Skrifgesag het die (teologiese geeste nog altyd in beroering — vandag (ná die Aufklarung! nog meer as gedurende die sestiende eeu. Gedurende die laaste paar jaar is ons in Suid-Afrika hardhandig uit ons isolement geruk en skielik lewensgroot gekonfronteer met die probleem van die Skrifgesag.

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

    Sabau, Adrian S [ORNL


    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

  5. Aspekte van die siekepastoraat

    H. J. C. Pieterse


    Full Text Available Die siekepastoraat vra ons aandag in hierdie tyd omdat die versorging van siekes ’n kenmerk is van die koms van die koninkryk van God. God se barmhartigheid het in sy volheid tot gelding gekom in die optrede van Jesus Christus. Die volle seën van die heil van die Ryk van God hou ook die versorging van die siekes in. Deur die heilswerk van Christus sien die blindes weer, loop die kreupeles, word melaatses gereinig, hoor die dowes, word dooies opgewek (Luk. 7:22.

  6. Die prediking oor die historiese stof van die Ou Testament

    F. N. Lion-Cachet


    Full Text Available Uit ’n steekproef wat gedoen is uit die preke wat in Die Kerkblad (1986- 1987 verskyn het, blyk dit dat 40% van hierdie preke historiese stof uit die Ou Testament as teks gebruik het.

  7. Effects of Alloying Elements on the Microstructures and Mechanical Properties of Heavy Section Ductile Cast Iron

    G.S. Cho; K.H. Choe; K.W. Lee; A.Ikenaga


    The effects of alloying elements on the as-cast microstructures and mechanical properties of heavy section ductile cast iron were investigated to develop press die material having high strength and high ductility.Measurements of ultimate tensile strength, 0.2% proof strength, elongation and unnotched Charpy impact energy are presented as a function of alloy amounts within 0.25 to 0.75 wt pct range. Hardness is measured on the broken tensile specimens. The small additions of Mo, Cu, Ni and Cr changed the as-cast mechanical properties owing to the different as-cast matrix microstructures. The ferrite matrix of Mo and Ni alloyed cast iron exhibits Iow strength and hardness as well as high elongation and impact energy. The increase in Mo and Ni contents developed some fractions of pearlite structures near the austenite eutectic cell boundaries, which caused the elongation and impact energy to drop in a small range. Adding Cu and Cr elements rapidly changed the ferrite matrix into pearlite matrix, so strength and hardness were significantly increased. As more Mo and Cr were added. the size and fraction of primary carbides in the eutectic cell boundaries increased through the segregation of these elements into the intercellular boundaries.

  8. Die gesag van die Heilige Skrif

    S.C.W. Duvenage


    Full Text Available Dit geld nie maar t.o.v. ’n ongeloofsbeskouing soos dié van Karl Jaspers nie wat beweer: „Die Bibel ist das Depositum eines Jahrtausends menschlicher Grenzerfahrung” of van die Rooms-Katolieke skrifbeskouing nie wat die kerklike leertradisie, soos dogmaties op die konsilie van Trente vasgelê is, beskou as die enigste gesaghebbende kriterium vir die kanonisering en interpretasie van die Skrif.

  9. Optimization of the die casting process parameters of an aluminum alloy cylinder body for motorcycle%摩托车铝合金缸体压铸工艺参数优化

    李洋; 张春香; 关绍康; 李海鹏; 曾博


    In order to solve the defects problem of aluminum alloy cylinder body casting for motorcycle, the effects of fast shot velocity, fast shot set point and mold temperature on the porosity area ( shrinkage cavity, shrinkage porosity and air hole ) of aluminum alloy cylinder body casting for motorcycle were systematically investigated using orthogonal experiment method and theoretical simulation in which AnyCasting numerical simulation software and ImageJ statistics software were exploited. The results indicate that the total porosity area of the casing increases with the increasing of the fast shot velocity,while decreases with the rising of fast shot set point and mold temperature. The optimal parameters are: fast shot velocity-2. 0 m/s, fast shot set point-280 mm and mold temperature-240℃. Using this set of the optimal parameters, the casting density was increased , the percentages of porosity area on the top surface and bottom surface of the casting were decreased about 21% and 68% ,respectively, and the casting scrap rate was reduced from 14% to 5%.%为解决摩托车铝合金缸体压铸件存在的缺陷问题,利用AnyCasting铸造数值模拟分析软件,采用正交试验方法,并借助ImageJ软件统计铸件的孔洞面积(缩孔缩松或气孔),系统研究了压铸工艺参数:快压射速度、快压射切换点位置及模具温度对摩托车铝合金缸体孔洞面积的影响规律.研究表明,铸件内的孔洞总面积随着快压射速度的增加而增加,随着快压射切换点位置和模具预热温度的增加而减小.本实验条件下的最优工艺参数为:快压射速度2.0 m/s、快压射切换位置280 mm、模具温度240℃.采用该组参数,使铸件致密度增大,上、下端面孔洞所占面积分别减少21%和68%,铸件废品率从14%降低到5%.

  10. Legal physician‐assisted dying in Oregon and the Netherlands: evidence concerning the impact on patients in “vulnerable” groups

    Battin, Margaret P; van der Heide, Agnes; Ganzini, Linda; van der Wal, Gerrit


    Background Debates over legalisation of physician‐assisted suicide (PAS) or euthanasia often warn of a “slippery slope”, predicting abuse of people in vulnerable groups. To assess this concern, the authors examined data from Oregon and the Netherlands, the two principal jurisdictions in which physician‐assisted dying is legal and data have been collected over a substantial period. Methods The data from Oregon (where PAS, now called death under the Oregon Death with Dignity Act, is legal) comprised all annual and cumulative Department of Human Services reports 1998–2006 and three independent studies; the data from the Netherlands (where both PAS and euthanasia are now legal) comprised all four government‐commissioned nationwide studies of end‐of‐life decision making (1990, 1995, 2001 and 2005) and specialised studies. Evidence of any disproportionate impact on 10 groups of potentially vulnerable patients was sought. Results Rates of assisted dying in Oregon and in the Netherlands showed no evidence of heightened risk for the elderly, women, the uninsured (inapplicable in the Netherlands, where all are insured), people with low educational status, the poor, the physically disabled or chronically ill, minors, people with psychiatric illnesses including depression, or racial or ethnic minorities, compared with background populations. The only group with a heightened risk was people with AIDS. While extralegal cases were not the focus of this study, none have been uncovered in Oregon; among extralegal cases in the Netherlands, there was no evidence of higher rates in vulnerable groups. Conclusions Where assisted dying is already legal, there is no current evidence for the claim that legalised PAS or euthanasia will have disproportionate impact on patients in vulnerable groups. Those who received physician‐assisted dying in the jurisdictions studied appeared to enjoy comparative social, economic, educational, professional and other privileges. PMID

  11. Die ontwrigting van die Afrikanervolk en volkseenheid

    H. du Plessis


    Full Text Available Die gevare wat ons Afrikanerdom voor die deur staan, is baie en ernstig. Daar is die gevaar van immigrasie van buitelanders, daar is die al driester geroep om gelykstelling tussen blank en gekleurd, daar is die dreigende oorheersing van ’n oppervlakkige Amerikaanse „jazz”-gees.

  12. Die Nasionale Vakterminologiediens (NVD

    L. A. Genis


    Full Text Available Die Nasionale Vakterminologiediens (NVD ressorteer onder die Hoofdirektoraat Kultuur en Vakkundige Hulp- dienste van die Departement van Nasionale Opvoeding. Die hoofdoelwit van die NVD is die skepping van ’n fijnksionele vakwoordeskat in veral Afrikaans, parallel met die inter- nasionaal gebruikte terminologieë.

  13. Titanium Aluminide Casting Technology Development

    Bünck, Matthias; Stoyanov, Todor; Schievenbusch, Jan; Michels, Heiner; Gußfeld, Alexander


    Titanium aluminide alloys have been successfully introduced into civil aircraft engine technology in recent years, and a significant order volume increase is expected in the near future. Due to its beneficial buy-to-fly ratio, investment casting bears the highest potential for cost reduction of all competing production technologies for TiAl-LPTB. However, highest mechanical properties can be achieved by TiAl forging. In view of this, Access e.V. has developed technologies for the production of TiAl investment cast parts and TiAl die cast billets for forging purposes. While these parts meet the highest requirements, establishing series production and further optimizing resource and economic efficiency are present challenges. In order to meet these goals, Access has recently been certified according to aircraft standards, aiming at qualifying parts for production on technology readiness level 6. The present work gives an overview of the phases of development and certification.

  14. Rapid Cycle Casting of Steel


    such as macrosegregation, hot tears, and blowholes are also difficult to control. Rheocasting l on the other hand, is a recent development which...viscosity. Advantages of the rheocasting process are: * Reduced attack of die or mold because of the reduced tempera- ture (by 1000 C for steel) and...4W W ’ V6W 4 1.2 THE SD PROCESS Many metals, including steel, can be cast at still lower tempera- soliifiction(2) tures than rheocasting by

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

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


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

  16. Die kritiese taak van die literator

    A. L. Combrink


    Full Text Available Die beoefening van die literêre kritiek was aanvanklik slegs ’n deeltydse aktiwiteit. Die vroegste literêre kritici was nie as sodanig kritici nie maar het as deel van hulle totale intellektuele aktiwiteit hulle ook uitgelaat oor die letterkunde. Die motivering wat hulle hiertoe gehad het sou in ons dag heeltemal verdag voorkom: ’n uitgesproke didaktiese of moraliserende houding was die reel.




    Full Text Available Modern production methods for casting articles include the use of sand- mould, metal-mould, die, and centrifugal castings. Castings produced using sand mould is known to have peculiar microstructures depending on average size, distribution and shape of the moulding sand grains and the chemical composition of the alloy. These affect the surface finish, permeability and refractoriness of all the castings. In this paper, the effect of using CO2 process, metal mould, cement-bonded sand mould and naturally-bonded sand mould on the hardness, tensile and impact strengths of as-cast 6063 Aluminum alloy is presented. The results show that there is significant increase in hardness(33.7 HB of the alloy when naturally-bonded sand mould is used for its production over that of metal, CO2 and cement moulds. The stress-strain curves behaviour of the samples also indicated that sample from naturally bonded sand has highest tensile strength with superior ductility. The alloy shows highest impact strength when metal mould is used for sample preparation in comparison with other moulds.

  18. Effects of Shot Process and Aging on Microstructure and Mechanical Properties of Die-Cast Al-5Mg-2Si-Mn Alloy%压射工艺及时效对Al-5Mg-2Si-Mn合金组织及性能的影响

    万里; 吴晗; 胡祖麒; 刘学强; 吴树森


    The effects of shot parameters and artificial aging treatment on the microstructure and mechanical properties of the die-casting Al-5Mg-2Si-Mn alloy were investigated. The results show that the die casting samples exhibits good surface with sound microstructure and absence of shrinkage and gas porosity under the condition of shot pressure 100 MPa, high-speed injection velocity and the shrift position of 220 mm. The tensile strength, yield strength and elongation can reach up to 351.1 MPa,200. 7 MPa and 13. 77% respectively. After artificial ageing treatment at 250 'C for 3 hours and then cooled in air, tensile strength, yield strength and elongation of the samples can reach 380. 5 MPa, 246. 9 MPa and 11. 48% respectively.%通过高强韧压铸铝镁合金的压铸工艺试验,研究了主要压射工艺参数和人工时效对该合金标准压铸试样的组织及力学性能的影响.结果表明,在压射比压、快压射速度、快压射转换位置分别为100 MPa、高速档和220 mm时,压铸试样的外观成形良好,组织致密,无缩孔、气孔缺陷,其抗拉强度、屈服强度和伸长率分别为351.1 MPa、200.7 MPa和13.77%;该试样经人工时效(250℃)保温3h后空冷,其抗拉强度、屈服强度和伸长率分别为380.5 MPa、246.9MPa和11.48%.

  19. When a child dies the world should stop spinning: an autoethnography exploring the impact of family loss on occupation.

    Hoppes, Steve


    The death of a loved one disrupts family-members' occupational lives. This paper explores the role and course of occupation during a time when my nephew died. A qualitative research methodology, autoethnography, is used to develop the narrative. I found that familiar occupations lost meaning during this time and even seemed absurd. Paradoxically, occupation helped forge a vital pathway back to health and reconstruction of meaning. Four stages of occupation during a family crisis are proposed: maintenance, dissolution, ambivalence, and restoration and adaptation. Reflections on occupational therapists' role during family crises are discussed, as are implications for further research.

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

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


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

  1. Die Via Dolorosa

    W. J. van der Merwe


    Full Text Available In die hartjie van Jerusalem, die heilige stad vir Jood, Mohammedaan en Christen staan daar ’n boog, die ,,Ecce Homoboog” genaamd, en 'n klein endjie daarvandaan, die Heilige Grafkerk.

  2. Nodular cast iron and casting monitoring


    In this paper quality monitoring of nodular cast iron and casting made of it is presented. A control system of initial liquid cast iron to spheroidization, after spheroidization and inoculation with using of TDA method was shown. An application of an ultrasonic method to assessment of the graphite form and the metal matrix microstructure of castings was investigated.

  3. Nodular cast iron and casting monitoring

    S. Pietrowski


    Full Text Available In this paper quality monitoring of nodular cast iron and casting made of it is presented. A control system of initial liquid cast iron to spheroidization, after spheroidization and inoculation with using of TDA method was shown. An application of an ultrasonic method to assessment of the graphite form and the metal matrix microstructure of castings was investigated.

  4. Luther die prediker

    J. J. van der Walt


    Full Text Available ’n Prediker moet ’n getroue herder wees wat magtig is in die Heilige Skrif, want die Woord bring die kerk voort. Daarom moet die prediker in sy bediening aan mense ’n woord van sekerheid hê deur seker te wees hy het die Woord van God. Met hierdie gedagtegang het Luther se pastorale besorgdheid vaste bodem vir die prediking in die gesag van die Woord van God.

  5. design, construction and performance evaluation of multiple casting ...


    Design and development of a new casting machine which perform and development of a new ... casting reduces the amount of entrapped air or gas in the die cavity. .... mm, diameter 15 mm and bottom of stirrer blade thickness 10 mm and ...

  6. Influence of Technological Parameters of Furane Mixtures on Shrinkage Creation in Ductile Cast Iron Castings

    Vasková I.


    Full Text Available Ductile cast iron (GS has noticed great development in last decades and its boom has no analogue in history humankind. Ductile iron has broaden the use of castings from cast iron into areas, which where exclusively domains for steel castings. Mainly by castings, which weight is very high, is the propensity to shrinkage creation even higher. Shrinkage creation influences mainly material, construction of casting, gating system and mould. Therefore, the main realized experiment was to ascertain the influence of technological parameters of furane mixture on shrinkage creation in castings from ductile iron. Together was poured 12 testing items in 3 moulds forto determine and compare the impact of various technological parameters forms the propensity for shrinkage in the casting of LGG.

  7. Linkage of spreaders an the LWL infrastructure of the control room Garzweiler II in the open-cast mining Garzweiler; Anbindung der Absetzer an die LWL-Infrastruktur des Leitstandes Garzweiler II im Tagebau Garzweiler

    Dueren, Daniel [RWE Power Aktiengesellschaft, Grevenbroich (DE). Tagebau Garzweiler, Infrastruktur Elektrotechnik - Technische Unterstuetzung (PCG-IE-T)


    In the Rhenish mining area nearly 100 million tons of brown coal were produced annually. The conveyors are connected with each other and with the central process control system. The control of the plant is performed by a control room. In light of the retrofitting of the band control center for the open-cast mining Garzweiler a broadband communication network based on OTN (Open Transport Network) was established. The connection of the spreader to the infrastructure of the control room via OTN nodes was performed in the years 2006 to 2010. Six spreaders as well as the associated belt grinding carriages can be connected to the central control of the band control station.

  8. 76 FR 5840 - The Basic Aluminum Castings Co., Cleveland, OH; Notice of Revised Determination on Reconsideration


    ... Employment and Training Administration The Basic Aluminum Castings Co., Cleveland, OH; Notice of Revised... Assistance (TAA) applicable to workers and former workers of The Basic Aluminum Castings Co., Cleveland, Ohio... are engaged in employment related to the production of aluminum die castings. New information revealed...

  9. Casting materials

    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)


    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.

  10. Stress/strain Modelling of Casting Processes in the Framework of the Control-Volume Method

    Hattel, Jesper Henri; Thorborg, Jesper; Andersen, Søren


    Realistic computer simulations of casting processes call for the solution of both thermal, fluid-flow and stress/strain related problems. The multitude of the influencing parameters, and their non-linear, transient and temperature dependent nature, make the calculations complex. Therefore the need......, the present model is based on the mainly decoupled representation of the thermal, mechanical and microstructural processes. Examples of industrial applications, such as predicting residual deformations in castings and stress levels in die casting dies, are presented...

  11. Wêreldmededingendheid en die tegnologie

    C. W. I. Pistorius


    Full Text Available Afgesien van die interne uitdagings wat die Heropbou- en Ontwikkelingsprogram (HOP aan Suid-Afrika bied, moet die land ook tred hou met die veranderende globale omgewing, spesifiek die toenemende belangrikheid van ekonomiese sekuriteit as komponent van nasionale sekuriteit. Die konsep van mededingendheid vergestalt die doelwit wat nagestreef moet word ten einde die ontluikende globale ekonomiese stryd aan te durf. As ’n belangrike drywer van ekonomiese welvaart is tegnologie een van die belangrikste sleutels tot internasionale mededingendheid. Tegnologiese innovasie is die proses wat as hefboom hiervoor gebruik moet word. Dit is egter nodig dat tegnologie, en spesifiek die proses van tegnologiese innovasie, formeel en gestruktureerd bestuur moet word, sowel op nasionale as firmavlak. Op nasionale vlak is die voorsiene Nasionale Innovasiestelsel beslis ’n stap in die regte rigting.

  12. The German lignite industry. Historical development, resources, technology, economic structures and environmental impact. Study; Die deutsche Braunkohlenwirtschaft. Historische Entwicklungen, Ressourcen, Technik, wirtschaftliche Strukturen und Umweltauswirkungen. Studie



    Lignite has a key role to play in the transformation of the energy system due to its specific structural features in terms of industry, company history, policy, economics, the environment and regional structures. Understanding these structural features of the German lignite industry is an important requirement for classifying the significance of the lignite industry up to now and for the redesigning of this industrial sector. From these environmental, economic and regulatory structural characteristics, which are interwoven in a variety of ways, the incentives arise for the mining and power plant operators to react to energy price signals or energy policy steering. The aim of this research study is to define these structural features, to compile comprehensively the basic data and information that is not always transparently available, to understand the interactions, to enable the navigation of issues that are partly very complex, and to classify into the long-term developments that are especially important for political and social processes. In 2016 approx. 12 percent of German primary energy consumption was met using lignite. At the same time, lignite has the highest carbon dioxide (CO2) emissions of the fossil fuels; it currently accounts for approx. 19 percent of Germany's total greenhouse gas emissions as well as approx. 46 percent of the total CO2 emissions of the electricity sector. As a result of the mining of lignite and its conversion into electricity, substantial adverse impacts beyond the entry of greenhouse gases into the Earth's atmosphere arise for other environmental media. These impacts include half of Germany's mercury emissions, approx. a third of its sulfur dioxide emissions and approx. a tenth of its nitrogen oxide emissions. Lignite mining in open-cast mines takes up a substantial amount of landscape and soil and requires huge interventions in the water balance. Relatively high costs arise for the recultivation and rehabilitation

  13. Squeeze casting of aluminum alloy A380: Microstructure and tensile behavior

    Li Fang


    Full Text Available A380 alloy with a relatively thick cross-section of 25 mm was squeeze cast using a hydraulic press with an applied pressure of 90 MPa. Microstructure and tensile properties of the squeeze cast A380 were characterized and evaluated in comparison with the die cast counterpart. Results show that the squeeze cast A380 possesses a porosity level much lower than the die cast alloy, which is disclosed by both optical microscopy and the density measurement technique. The results of tensile testing indicate the improved tensile properties, specifically ultimate tensile strength (UTS: 215.9 MPa and elongation (Ef: 5.4%, for the squeeze cast samples over those of the conventional high-pressure die cast part (UTS: 173.7 MPa, Ef: 1.0%. The analysis of tensile behavior shows that the squeeze cast A380 exhibits a high tensile toughness (8.5 MJ·m-3 and resilience (179.3 kJ·m-3 compared with the die cast alloy (toughness: 1.4 MJ·m-3, resilience: 140.6 kJ·m-3, despite that, during the onset of plastic deformation, the strain-hardening rate of the die cast specimen is higher than that of the squeeze cast specimens. The microstructure analyzed by the scanning electron microscopy (SEM shows that both the squeeze and die cast specimens contain the primary α-Al, Al2Cu, Al5FeSi phase and the eutectic Si phase. But, the Al2Cu phase present in the squeeze cast alloy is relatively large in size and quantity. The SEM fractography evidently reveals the ductile fracture features of the squeeze cast A380 alloy.

  14. Die spel van assosiasies in en om 'Die verlossing van die beeld' van Breyten Breytenbach

    P.A. du Toit


    Full Text Available The play of association in and around 'The liberation of the image' by Breyten Breytenbach This analysis focuses on the conjunction of memory and imagination, which is an important impulse in, and key to, Breytenbach’s work. The play with language and with associations, the foregrounding, in the short story, “Die verlossing van die beeld” (Breytenbach, 1983 with its metafictional title and apparently divergent motifs (rain/water, watch, onion, the death and burial of a grandfather acts, as it were, as an invitation to the reader to become a co-player. The reader ventures on a search for traces, intertextual links within the Breytenbach oeuvre and for already acknowledged influences such as Surrealism (which in turn casts some light on the strange title of the story and the Eastern philosophies such as Zen and the even older Taoism. The analysis also takes into account the context in which “Mouroir” was written, namely Breytenbach’s term in prison (1975-1982. Seeing that the writer had to hand in his manuscripts to the jail authorities regularly, he might have decided, consciously or by intuition, to hide some thoughts and feelings behind a screen or a mask, in, for example in “Die verlossing van die beeld”, a lighter tone and irony.

  15. Selection of the Optimal Cooling Parameters to the Multi-Cavity Die

    Chiaming; Yen; Jui-Cheng; Lin; Wujeng; Li


    This study is subject to the finite element and abd uc tive network method application in the multi-cavity die. In order to select the optimal cooling system parameters to minimize the warp of a die-casting die, t he Taguchi's method and the abductive network are used. These methods are appli ed to create an efficient model with functional nodes for the considered problem . Once the cooling system parameters are developed, this network can be used to predict the warp for the die-casting die accurately. A ...

  16. Mechanism and application of a newly developed pressure casting process:horizontal squeeze casting

    Li Peijie; Huang Xiusong; He Liangju; Liu Xiangshang; Wang Benci


    Compared to traditional high-pressure die casting (HPDC), horizontal squeeze casting (HSC) is a more promising way to fabricate high-integrity castings, owing to a reduced number of gas and shrinkage porosities produced in the casting. In this paper, the differences between HSC and HPDC are assessed, through which it is shown that the cavity ifling velocity and the size of the gating system to be the most notable differences. Equipment development and related applications are also reviewed. Furthermore, numerical simulation is used to analyze the three fundamental characteristics of HSC: slow cavity ifling, squeeze feeding and slow sleeve ifling. From this, a selection principle is given based on the three related critical casting parameters: cavity filling velocity, gate size and sleeve ifling velocity. Finaly, two speciifc applications of HSC are introduced, and the future direction of HSC development is discussed.

  17. Mechanism and application of a newly developed pressure casting process: horizontal squeeze casting

    Li Peijie


    Full Text Available Compared to traditional high-pressure die casting (HPDC, horizontal squeeze casting (HSC is a more promising way to fabricate high-integrity castings, owing to a reduced number of gas and shrinkage porosities produced in the casting. In this paper, the differences between HSC and HPDC are assessed, through which it is shown that the cavity filling velocity and the size of the gating system to be the most notable differences. Equipment development and related applications are also reviewed. Furthermore, numerical simulation is used to analyze the three fundamental characteristics of HSC: slow cavity filling, squeeze feeding and slow sleeve filling. From this, a selection principle is given based on the three related critical casting parameters: cavity filling velocity, gate size and sleeve filling velocity. Finally, two specific applications of HSC are introduced, and the future direction of HSC development is discussed.

  18. The UK Casting Industry

    Jincheng Liu


    The casting production in the UK in 2004 is presented and analysed. The UK casting industry has played an important role in world casting and manufacturing production. However recent years the rapid development of some developing countries has been shifting the casting production from the western industrialized countries including the UK. The UK casting industry and associated research and technology organizations, universities have been working together very hard to face the serious competition to make the UK casting industry have a sustainable future. The UK casting industry remains strong and plays an important role in world casting and manufacturing production.


    Ivan Tomašić


    Full Text Available This paper presents an analysis of a complexity of interrelated structural, petrologic and climatic factors that considerably affect the instabilities in the open cast mine of Gradna, near Samobor. The instabilities provoke the slope failures such as slides and slumps of rock material. During the protracted periodical investigations, the relationship among the factors of regional geology, tectonics, structural geology, petrography, engineering geology, rock mechanics and the rock mining technology was observed in the area. The local control of hydrogeologic properties, as well as climatic fluctuations of temperature and precipitation on the slope stability, was also recognized. It turned out that the structural relationships, characteristic of the manifold cataclased dolomite, stimulated the development of local instabilities, particularly during the period of low temperatures affecting the process of ground-water accumulation. When the temperatures are worm, the ground-water circulation is slow, exerting only the small-scale influence on the local instabilities (the paper is published in Croatian.

  20. Die rol van die blanke werker in die motivering van die swart werker

    G. J. Oosthuizen


    Full Text Available The motivation of the Black worker can not be studied in isolation since the White worker still holds many executive positions and therefore has an influence on the Black workers' motivation. The role of the White worker in motivating the Black worker in a specific organisation and the attitude and leadership approach of the White worker on the existence/nonexistence and relative satisfaction of the needs of Black workers are discussed.Opsomming Die motivering van die Swart werker kan nie in die huidige situasie in isolasie bestudeer word nie, omdat die Blanke werker steeds in die bestuursposisie is en daarom die motivering van die Swart werker kan beïnvloed. Hierdie ondersoek was daarop gerig om die rol van die Blanke werker in die motivering van die Swart werker nader te ondersoek. Die houding en die leierskapsbenadering van die Blanke werker teenoor die Swart werker is gemeet, asook die behoeftes wat volgens die Blanke werker by die Swart werker bestaan, bevredig is, of nie bestaan nie. Die behoeftes van Swart werkers, soos deur hulleself gesien, is ook ondersoek. Ten opsigte van sekere aspekte is beduidende verskille gevind.

  1. Die verbondeling in verband

    J. A.L. Taljaard


    Full Text Available Daar is dikwels en deur groot outoriteite al geskryf oor die mens in die samelewing. Hier wil ons egter die saak probeer aanraak uit ’n nuwe hoek, veral om die Skrifbeligting van die siening te benader. Vanselfsprekend verg hierdie benaming ’n skrifmatige mensbeskouing, maar ook ’n skrifmatige verbandsbeskouing. Die mens staan egter nie slegs in verhouding tot sy medemens nie maar ook in verhou­ ding tot stof, plant en dier. Boweal staan die mens in verhouding tot God, en hierdie verhouding is deurslaggewend vir al die ander verhoudinge waarin die mens hom bevind. Tog staan die mens ook in verhouding tot homself; wie kan die diepere roersele van die menslike siel peil, wie weet van die wroeginge, vreugde, leed en genot van die mens beter as hyself? Ook hierdie aspek verdien ons aandag. Op volledigheid kan nie aanspraak gemaak word nie, dit is ook nie my bedoeling nie. Die bedoeling is maar om die omvang van die tema aan te dui, die gedagtes te prikkel en veral om aan te spoor tot nuwe denkoriëntering waarin ook terminologies gebreek behoort te word met die neo-skolastiek binne reformatoriese lyn.

  2. Wege in die Zukunft

    Kauermann, Göran; Mosler, Karl

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

  3. Die Gewalt der Frauen

    Angelika Ebrecht


    Full Text Available Anhand historischer Beispiele aus der Zeit der letzten Jahrhundertwende in Europa stellt die Autorin den Zusammenhang von Transgression, Aggression und Inversion dar. Gegen die gängige Auffassung, Gewalt sei männlich, setzt sie Selbst- und Fremdentwürfe von Frauen, die als Duellantinnen, Soldatinnen und Mörderinnen die gesellschaftlich festgelegten Grenzen der Gewalt verletzten. Sie interpretiert dies als Versuch, die Geschlechtergrenzen zu überschreiten und sich eine Subjektposition anzueignen.

  4. Cast irons


    Cast iron offers the design engineer a low-cost, high-strength material that can be easily melted and poured into a wide variety of useful, and sometimes complex, shapes. This latest handbook from ASM covers the entire spectrum of one of the most widely used and versatile of all engineered materials. The reader will find the basic, but vital, information on metallurgy, solidification characteristics, and properties. Extensive reviews are presented on the low-alloy gray, ductile, compacted graphite, and malleable irons. New and expanded material has been added covering high-alloy white irons used for abrasion resistance and high-alloy graphitic irons for heat and corrosion resistance. Also discussed are melting furnaces and foundry practices such as melting, inoculation, alloying, pouring, gating and rising, and molding. Heat treating practices including stress relieving, annealing, normalizing, hardening and tempering, autempering (of ductile irons), and surface-hardening treatments are covered, too. ASM Spec...

  5. Grain refinement of gravity die cast secondary AlSi7Cu3Mg alloys for automotive cylinder heads%重力铸造汽车气缸盖用AlSi7Cu3Mg 二次合金的晶粒细化

    Giordano CAMICIA; Giulio TIMELLI


    The effects of AlTi5B1 grain refinement and cooling rate on the microstructure and mechanical properties of a secondary AlSi7Cu3Mg alloy were reported. Metallographic and image analysis techniques have been used to quantitatively examine the macrostructural and microstructural changes occurring with the addition of grain-refining agent at different cooling rates by using a step casting die. The results indicate that the addition of AlTi5B1 produces a fine and uniform grain structure throughout the casting and this effect is more pronounced in the slowly solidified regions. Increasing the cooling rate, lower amount of grain refiner is necessary to produce a uniform grain size throughout the casting. On the other hand, the initial contents of Ti and B, present as impurity elements in the supplied secondary alloy, are not sufficient to produce an effective grain refinement. The results from the step casting geometry were applied to investigate a gasoline 16V cylinder head, which was produced by gravity semi-permanent mould technology. The grain refinement improves the plastic behaviour of the alloy and increases the reliability of the casting, as evidenced by the Weibull statistics.%研究了 AlTi5B1晶粒细化和冷却速率对 AlSi7Cu3Mg 二次合金显微组织和力学性能的影响。采用阶梯铸模在不同冷却速率下制备添加晶粒细化剂的合金,并利用金相和图像分析技术定量研究了合金的宏观组织和显微组织。研究结果表明,添加 AlTi5B1后,整个铸件具有细小均匀的晶粒组织,且在慢速凝固区域效果更显著。当冷却速率增加时,少量细化剂就可使铸件获得细小均匀组织。另外,原材料中的 Ti 和 B 以杂质的形式存在,不足以形成有效的晶粒细化效果。利用阶梯铸造法的研究结果研究了重力半固模铸造16V 汽油发动机气缸盖。Weibull 统计结果表明,晶粒细化改善了合金的塑形变形行为,提高了铸件的可靠性。

  6. Antiglobalisierung die Andere Globalisierung

    Ljiljana Croce


    Das Ziel der Arbeit ist, ein je größeres Interesse an diesem Thema zu erwecken und auf die Gefahren hinzuweisen, denen wir alle verlaufen, wie die Armen, sowie auch die Reichen und die kleine Gruppe der zum mittleren Stand gehörenden, die immer mehr in die offene Armut versinken. Es wäre zu viel, in einer Welt solcher Globalisierung, die soziale Empfi ndlichkeit der Menschen zueinander zu erwarten. In Wirklichkeit geht sie immer mehr verloren. Der Mensch als Einzelperson, sowie auch die Völke...

  7. The ancient Chinese casting techniques


    In the course of Chinese civilization, which lasted more than 5,000 years, casting production has made a huge contribution. In this paper, some representative metal castings were presented. According to their forming techniques, they can be grouped into stone mould casting, clay mould casting, ablation casting, lost wax casting, stack casting, permanent mould casting, sand casting, etc. According to their materials, they can be categorized into tin bronze, bimetallic bronze, malleable cast ir...

  8. Verrekening van die kragveld van die verbond in die inkleding van die kommunikatiewe driehoeksverhouding tussen teks, hoorder en prediker


    In hierdie artikel word die kommunikatiewe driehoeksverhouding tussen die Bybelse teks, die hoorders en die prediker homileties verken. Die probleemstelling waarmee gewerk word handel oor potensiële versteurings wat kan plaasvind in hierdie driehoeksverhouding wanneer die hoorders en die prediker in hulle menslike beperktheid in verbinding gebring word met die ewige Woord van God soos dit in die Bybelse teks na vore kom. In die loop van die artikel word die volgende aspekte verken: ’n Ideale...

  9. Optimization of squeeze casting parameters for non symmetrical AC2A aluminium alloy castings through Taguchi method

    Senthil, P. [Coimbatore Institute of Engineering and Technology, Coimbatore (India); Amirthagadeswaran, K. S. [Government College of Technology, Coimbatore (India)


    This paper reports a research in which an attempt was made to prepare AC2A aluminium alloy castings of a non symmetrical component through squeeze casting process. The primary objective was to investigate the influence of process parameters on mechanical properties of the castings. Experiments were conducted based on orthogonal array suggested in Taguchi's offline quality control concept. The experimental results showed that squeeze pressure, die preheating temperature and compression holding time were the parameters making significant improvement in mechanical properties. The optimal squeeze casting condition was found and mathematical models were also developed for the process.

  10. Thin Wall Iron Castings

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


    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.

  11. Die Motions of New Forging Process Using IntermediateDie Assembly


    The die motions of a new forging process for automation with an intermediate die assembly called hamburger were analyzed through high-speed video pictures. The results showed that the upper die that is assembled in the hamburger and retained over the lower die collides few times with the ram and workpiece, but sound products can be obtained with less sticking in spite of the lowered impacts of hit.

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

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


    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.

  13. Die voorspellingswaarde van die takseersentrum: 'n Oorsig

    H. J. Pietersen


    Full Text Available The assessment centre: a brief review of predictive value. Factors such as the rise of the professional manager, industrialization and worker expectations have, over the last few decades, increasingly placed managers in the limelight as a key occupational group. In this regard the assessment centre has become prominent as a method for the identification of managerial potential. However, a brief review of the relevant research literature indicates low predictive variances for the managerial assessment centre. This fact, together with the limited scope of the assessment centre, therefore necessitates, amongst other things, a wider research perspective which will include other work and non-work related factors as well. Opsomming Verskynsels soos die opkoms van die professionele bestuurder, industrialisering en stygende werkerverwagtinge het meegebring dat die kollig die afgelope paar dekades al hoe meer op bestuurders as sleutelberoepskategone geplaas is. In hierdie verband het veral die takseersentrum aandag gekry as 'n metode vir die identifisering van bestuurs- potensiaal 'n Kort oorsig van die betrokke navorsingsliteratuur toon egter lae voorspellingsvariansiesyfers vir die takseersentrum aan. Hierdie feit, tesame met die beperkte fokus van die takseersentrum, noodsaak, onder andere, 'n wyer navorsingsperspektief wat ook ander relevante werk- en nie-werkverwante faktore msluit.

  14. The impacts of climate change on soils. Investigations of impacts of climate change on soil erosion by water; Wirkungen der Klimaaenderungen auf die Boeden. Untersuchungen zu Auswirkungen des Klimawandels auf die Bodenerosion durch Wasser

    Wurbs, Daniel [Geoflux GbR, Halle (Saale) (Germany); Steininger, Michael [Mitteldeutsches Institut fuer angewandte Standortkunde und Bodenschutz (MISB), Halle (Saale) (Germany)


    Climate forecasts regarding the 21st century raise expectations in soil erosion growth mainly due to changes in heavy precipitation characteristics and ground cover in line with the adaptation of the crop growing season to future climatic conditions. The aim of this study initiated by the Federal Environmental Agency was, to examine the impacts of climate change on soil erosion by water in Germany using data calculated by the statistical climate model WETTREG. Soil erosion by water was estimated following an USLE approach implemented in ABAGFlux and TerraFlux with focus on the usage-based erosion potential in German agricultural areas. In the 2nd project phase the USLE R factor was recalculated for the recent (1971-2000) and future climate periods (2011-2040, 2041-2070, 2071-2100) using statistical methods such as the peak over threshold method. Furthermore the climate-induced change of the C-factor was analyzed with respect to changes of culture periods, ground cover and the monthly R factor. Scenarios regarding future percentage of conservation tillage systems as also the potential and usage-based soil erosion for these four climate periods have been modelled. The results underline a requirement to differentiate the view on temporal and spatial development of R factors and potential soil erosion. There are minor changes between 2011 and 2040 followed by an increased erosion hazard in western and north-western Germany after 2041 while eastern and southern Germany face a downward trend of R factors, derived using WETTREG data of a reference period 1971 to 2000. Between 2071 and 2100 potential soil erosion rises with R factors above the actual state due to more heavy rain falls nearly all over Germany. The resulting temporal offset of culture periods and the monthly distribution of the R factor cause rising C factors in all time periods as also increasing usage-based soil erosion hazard in Germany. This study shows that soil erosion exists in Germany. The problem

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

    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)


    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.

  16. Die ontwikkeling van die bestuursmotiveringsvraelys (BMV

    A. S. Engelbrecht


    Full Text Available The development of the Managerial Motivation Questionnaire (MMQ: Several criticisms of the psychometric suitability of existing measures of managerial motivation are reported in the literature. This study aimed at developing a new psychometrically sound instrument, the Managerial Motivation Questionnaire (MMQ. This was done on the basis of a comprehensive study of the literature on managerial motivation and the role-motivation theory. The preliminary MMQ was systematically shortened and refined until the final MMQ of 98 items was composed. This was based on social desirability and semantic appraisal, item analysis and factor analysis of the questionnaire. The results indicate that it was possible to develop a final MMQ that was relatively free of social desirability. It further demonstrated satsifactory internal consistencies on two samples (a = 0/90, N = 360; a = 0/91, N = 535, where all subscale items were found to be relatively pure measures of the isolated factors. Although some evidence was found providing support for the reliability of the MMQ, a need for further research on the construct validity of managerial motivation still exists. Opsomming In die literatuur word verskeie punte van kritiek teen die psigometriese geskiktheid van bestaande meetinstrumente van bestuursmotivering gerapporteer. Die doelstelling van hierdie studie was dus om aan die hand van die konseptuele omiyning van bestuursmotivering, en die rolmotiveringsteorie as algemene verwysingsraamwerk, 'n nuwe psigometries aanvaarbare meetinstrument, die Bestuursmotiveringsvraelys (BMV, te ontwikkel. Op grond van sosiale wenslikheids- en semantiese beoordeling, itemontleding en faktorontleding van die voorlopige BMV is die vraelys stelselmatig verkort en verfyn totdat die finale BMV van 98 items saamgestel is. Die resultate dui daarop dat hierdie studie wel daarin geslaag het om 'n finale BMV te ontwikkel wat relatief vry van sosiale wenslikheid is, bevredigende interne

  17. Optimization of Squeeze Casting for Aluminum Alloy Parts

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


    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

  18. Die sestienpersoonlikheidsfaktorvraelys as hulpmiddel by die takseersentrum

    J. C. D. Augustyn


    Full Text Available The 16PF Personality Test as an aid to the assessment centre Assessment centres still remains costly and thime consuming. This study investigates the reduction of time and costs by the use of the 16 PF Personality Test as a method for measuring management dimensions. Promising results were obtained with a relatively small sample for the prediction of initiative and perseverance. Significant multiple correlations were also found for three criteria of management success. Further research may establish the use of the 16 PF as an aid to management assessment and thereby reduce the costs and time involved in assessment centres. Opsomming Takseersentrums se grootste probleem is gelee in die koste en tyd wat dit behels. Hierdie studie ondersoek die moontlikheid om beide te verminder deur die aanwending van die 16 PF Persoonlikheidsvraelys vir die meting van bestuursdimensies. Belowende resultate is met 'n relatiewe klein steekproef bevind ten opsigte van die voorspelling van inisiatiefen deursettingsvermoe. Beduidende meervoudige korrelasies is ook ten opsigte van drie kriteria van bestuursukses bevind. Verdere navorsing kan die gebruik van die 16 PF as hulpmiddel by bestuursevaluering vestig en sodoende die tydsduur en koste van takseersentrums verminder.


    norm aan die een kant en deur die S^^eeksnorm aan die ander." (ibid. 384). ...... grondslag, hoewel die groot aantal voorbeelde uit die werke van Thomas Mann ...... Mentrup, W., & P. Kuhn, (1980) "Deutsche Sprache in Osterreich und in der.

  20. Die etiek van Luther

    J. H. van Wyk


    Full Text Available Dink ons aan die etiek van Luther dan spring onmiddellik ’n paar boeiende uitsprake van hom na vore soos o.a. dat Christene vanuit die gemeenskap met Christus nuwe dekaloë moet maak wat helderder as die van Moses kan wees, of dat ons in bepaalde sin vir ons naaste ’n Christus moet word. Die bydrae van Luther 'tot die Christelike etiek is sonder twyfel van groot betekenis en die bestudering daarvan die moeite werd. Luther is geprys as rewolusionêr en verguis as konserwatis, hy is geëer as iemand wat weer die ware be­tekenis van godsdiens ontdek het toe die lewe vervloei het in etiek. Of dit egter korrek is om sy etiek as konserwatief te tipeer, soos White doen, moet betwyfel word.

  1. 高真空压铸铝合金轿车底盘部件的压射工艺试验及优化%Experiment and Optimization of Shot Parameters of High Vacuum Die Casting for Aluminum Alloy Car Chassis Part

    林海; 万里; 刘后尧; 张寓朝; 吴湛方; 杨林方; 李高; 吴树森


    采用自主研发的高真空压铸控制系统,以某铝合金轿车底盘部件为对象,研究了高真空压铸工艺参数如真空度、抽真空时间、压射速度及高速切换点等对铸件内部质量及力学性能的影响.试验结果表明:该铝合金轿车底盘关键部件的最佳高真空压铸工艺参数:抽真空启动位置110 mm,抽真空停止位置700 mm;冲头慢压射速度0.19 m/s,快压射速度5.8 m/s;慢/快速转换点即高速切换点240 mm;型腔真空度91 kPa以上.高真空压铸的底盘部件本体试样抗拉强度达到281.56 MPa,屈服强度达到155.44 MPa、伸长率达到7.34%,完全满足该铸件的技术要求.经过严格的产品检测,该铝合金轿车底盘部件已成功用于某国产自主品牌轿车.%Based on innovative high vacuum control system, effects of shot parameters including vacuum level, venting time, shot velocity and switch position of fast velocity on casting quality and mechanical properties were investigated for the high vacuum die-cast car chassis part in this paper.The results show that optimal process parameters are as follows: the vacuumed startup and stop position are 110 mm and 700 mm respectively, and the vacuum level of cavity is up to 91 kPa;meanwhile the slow and fast velocity of the injection punch are 0.19 and 5.8 m/s, and switch position of fast velocity is 240 mm.The round car chassis part can be achieved under above parameters,whose tensile strength is 281.56 MPa, yield strength 155.44 MPa and elongation up to7.34%.The chassis part was successfully employed in a domestic own-brand car.

  2. The impact of Erasmus mobility on the professional career: Empirical results of international studies on temporary student and teaching staff mobility Die Auswirkungen der Erasmus-Mobilität auf die berufliche Entwicklung : empirische Ergebnisse internationaler Studien über temporäre Mobilität von Studierenden und Lehrenden

    Constanze Engel


    Full Text Available The impact of an Erasmus study period abroad for mobile students and teaching assignments of Erasmus teachers on professional development is the focus of the article. Temporary study abroad is expected to have a positive impact on personal and academic development, but also to be conducive to transition to employment and career development. Though the impact has been declining, study abroad remains an important experience for the professional career. Erasmus teaching assignments often do not last longer than a few days. Nevertheless, mobile teachers report a positive impact on their career. The article is based on the VALERA Study1 “The professional value of Erasmus mobility”, a European-wide evaluation study by the International Centre for Higher Education Research Kassel.Im Zentrum des Artikels steht der Einfluss temporärer internationaler Studien- und Lehraufenthalte auf den Berufsweg ehemaliger Erasmus Studierender und Lehrender. Es wird erwartet, dass ein Auslandsaufenthalt während des Studiums nicht nur auf die persönliche und akademische Entwicklung der mobilen Studierenden einen positiven Einfluss hat, sondern auch auf den Übergang in den Beruf und die erste Karriere. Ein Auslandsaufenthalt im Studium hat einen sehr wichtigen Einfluss auf die berufliche Entwicklung ehemals mobiler Studierender, auch wenn der individuelle Ertrag im Laufe der Zeit gesunken ist. Lehraufenthalte im Rahmen des Erasmus Programmes dauern häufig nicht länger als wenige Tage. Dennoch berichten auch die Erasmus Lehrenden von einem positiven Einfluss des Lehraufenthaltes im Ausland auf ihre berufliche Entwicklung. Dieser Artikel basiert auf Ergebnissen der VALERA-Studie “Der berufliche Ertrag der Erasmus-Mobilität“, einer europaweiten Evaluierungstudie des Erasmus Programms durchgeführt vom Internationalen Zentrum für Hochschulforschung Kassel.

  3. Ambrosius en die virginitas

    C. J. Malan


    Full Text Available Ambrosius het met reg die benaming “Leraar van Maagdelikheid” ontvang (Dooley, 1948:119. Die opmerking van Thamin: “C’est une vertu proprement chrétienne que la vertu de virginité, proclame tout d’abord saint Ambroise” (1895:344, gee dadelik aanleiding tot die vraag of Ambrosius dan geen waardering vir die huwelik gehad het nie. Hierdie vraag word nog meer dringend as sy beskrywing van die kruis van die getroude lewe nagegaan word.

  4. Navorsing op die gebied van die sosiale wetenskappe*

    P. M. Robbertse


    Full Text Available In Hollands is die woord scientia vertaal met wetenskap, wat sowel die natuur- as die geesteswetenskappe insluit, waardeur die woordsy oorspronklike betekenis behou. Die neiging bestaan om die Engels science met wetenskap in Afrikaans te vertaal, waarmee dan eintlik die natuurwetenskap bedoel word.

  5. Foute in die meting van die aarde se magneetveld met die protonmagnetometer

    G. P. Hancke


    Full Text Available Die tipiese foute wat voorkom wanneer die metode van periode-meting gebruik word vir die bepaling van die presessiefrekwensie van die magnetiese moment van protone, word bespreek, en metodes om dit teen te werk word voorgestel. Belangrike gevolgtrekkings wat sal lei tot die optimale funksionering van die periodemeter, word gemaak — veral ten opsigte van die meettyd, polarisasietyd en die eienskappe van die sensorvloeistof.

  6. Wake up and Die

    Schubart, Rikke


    Anmeldelse af den colombianske gyserfilm Volver a morir (eng. titel Wake Up and Die) af Miguel Urrutia......Anmeldelse af den colombianske gyserfilm Volver a morir (eng. titel Wake Up and Die) af Miguel Urrutia...

  7. Die radio in Afrika

    S. de Villiers


    Full Text Available Omvang van radio-uitsendings in en na Afrika. — Redes vir die versnelde tempo van uitbreiding. — Radio as die geskikste massa-kommunikasiemiddel vir Afrika. — Faktore wat die verspreiding bemoeilik. — Skouspelagtige toename in luistertalle.Toe Plinius, wat in die jaar 79 oorlede is, in sy „Historia Naturalis” verklaar het dat daar altyd iets nuuts uit Afrika afkomstig is, kon hy nouliks voorsien het dat die „iets" negentien eeue later in die lug sou setel wat hierdie reuse-vasteland oorspan — ’n Babelse spraakverwarring en ’n ongekende, verbete woorde-oorlog in die etergolwe, onder meer daarop bereken om die harte en hoofde van derduisendes te verower.

  8. Interfacial heat transfer in squeeze casting of magnesium alloy AM60 with variation of applied pressures and casting wall-thicknesses

    Zhang, Xuezhi; Fang, Li; Sun, Zhizhong; Hu, Henry; Nie, Xueyuan; Tjong, Jimi


    The heat transfer coefficient at the casting-die interface is the most important factor on the solidification process. With the 75-ton hydraulic press machine and P20 steel die mold, 5-step castings of magnesium alloy AM60 with different wall-thicknesses (3, 5, 8, 12, 20 mm) were poured under various hydraulic pressures (30, 60, and 90 MPa) using an indirect squeeze casting process. Thermal histories throughout the die wall and the casting surface have been recorded by fine type-K thermocouples. The in-cavity local pressures measured by pressure transducers were explored at the casting-die interfaces of 5 steps. The casting-die interfacial heat transfer coefficients (IHTC) initially reached a maximum peak value followed by a gradually decline to the lower level. Similar characteristics of IHTC peak values can be observed at the applied pressures of 30, 60 and 90 MPa. With the applied pressure of 90 MPa, the peak IHTC values from steps 1 to 5 varied from 5623 to 10,649 W/m2 K. As the applied hydraulic pressure increased, the IHTC peak value of each step was increased accordingly. The wall thickness also affected IHTC peak values significantly. The peak IHTC value and heat flux increased as the step became thicker. The empirical equations relating the IHTCs to the local pressures and the solidification temperature at the casting surface were developed based on the multivariate linear and polynomial regression.

  9. LED环氧灌封工艺对其可靠性的影响%Impact of LED Epoxy Casting Process on Its Reliability



    根据实际工作中分析发光二极管(LED)产品失效问题所获得的经验,探讨环氧树脂灌封工艺对LED可靠性的影响.采用理论结合试验验证的方法,从环氧树脂材料性能、固化工艺条件和改善树脂材料性能等方面,总结出环氧树脂灌封工艺影响LED可靠性的具体因素.环氧树脂材料的性能参数如玻璃化转变温度、热膨胀系数和弹性模量等会影响LED耐焊接热和光衰的能力;降低固化工艺条件会减少LED内应力,防止芯片隐裂;在环氧树脂中添加偶联剂可以提高LED产品气密性,防止水汽渗透,提高LED可靠性.最后建议应当根据不同LED的可靠性要求,选择合适的环氧树脂和固化工艺条件.%According to the experience gained from the analysis of light emitting diode (LED) product failure problems in practical working, the impact of epoxy casting process on LED reliability was discussed. With the method of combining theory and experiment, the specific factors of epoxy resin casting process to influence LED reliability were summarized from aspects including material properties of epoxy resin, curing process condition and resin material performance improvement. The epoxy resin material performance parameters such as glass transition temperature, thermal expansion coefficient and elastic modulus will affect LED resistance to soldering heat and light decay; lowering LED curing process conditions will reduce LED inner stress and prevent the chip from hidden cracking; adding coupling agents in epoxy resin can improve the air tightness of LED products, prevent moisture penetration, and improve LED reliability. Finally, the suggestion of choosing appropriate epoxy resin and curing process conditions according to different LED reliability requirements was brought up.

  10. LLNL casting technology

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


    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.

  11. Die verhouding doop en geloof

    L. Floor


    Full Text Available By die aanvalle wat op die kinderdoop geloods word, kom telkens die verhouding doop en geloof ter sprake. Die geloof is so wesentlik met die doop verbonde, sodat daar nie gedoop mag word waar die geloof nie aanwesig is nie. 0ns lees inderdaad dwarsdeur die Nuwe Testament van ’n innige samehang wat daar tussen geloof en doop beslaan.

  12. Soldier caste influences on candidate primer pheromone levels and juvenile hormone-dependent caste differentiation in workers of the termite Reticulitermes flavipes

    Caste systems and the division of labor they make possible are common underlying features of all social insects. Multiple extrinsic factors have been shown to impact caste differentiation; for example, primer pheromones are chemical signaling molecules produced by certain castes that impact developm...

  13. Die gebruik van parallelplaatreologie vir die bepaling van die intrinsieke viskositeit van poli-etileentereftalaat

    O. C. Vorster


    Full Text Available Die bepaling van die intrinsieke viskositeit van poli-etileentereftalaat word bemoeilik deur die feit dat daar tans slegs twee metodes in gebruik is. In die eerste metode word die bepaling deur middel van oplossingsviskometrie gedoen, maar die toksisiteit van die oplosmiddel, asook die tydperk wat dit neem om die bepaling te doen, is ’n probleem. Die tweede metode word beperk deur die kompleksiteit en beskikbaarheid van die apparatuur in Suid-Afrika. In hierdie studie word ’n alternatiewe metode, gebaseer op parallelplaatreologie, voorgestel wat albei hierdie probleme oorkom en die resultate sodoende verkry, word vergelyk met dié wat met bestaande metodes verkry is.

  14. Die invloed van die neo-marxistiese kultuuranalise op die Wêreldraad van Kerke en die Gereformeerde Kerke van Nederland

    J. M. Vorster


    Full Text Available Toe die studente dwarsoor die VSA en Europa in die laat sestigerjare ’n plotselinge en radikale verset openbaar het teen die bestaande orde, het hulle die deur geopen vir ’n nuwe mededinger om die hart van die Westerse kultuur. Dit is die nou reeds bekende neo-Marxisme. Sedertdien het hierdie jongeling sy voetspore op vele vlakke van die Westerse kultuur gelaat.

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

    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


    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.

  16. Die lebensvision des semonides

    Milivoj Sironić


    Full Text Available Der Autor analysiert die Weibersatire des Semonides und andere seiner kurzen Fragmente. Dabei kommt er zu der Schlussfolgerung, dass sich die Verse der Satire durch eine gute Technik auszeich­ nen, dass aber auch eine unnötige Weitschweifigkeit nicht zu Ubersehen ist. Trotzdem kann man jedoch dem Dichter nicht die künstlerische Überzeugungskraft absprechen, wie auch die Ten­ denz nach Detailschilderungen und die Feinheit geistreicher Charakterisierungen. Die Aussage beinhaltet manchmal eine be­ stimmte innere Ironie in der Einfachheit der Wörter.In kurzen Fragmenten wird die Fähigkeit des Semonides sichtbar, sich sehr präzise auszudrücken. Seine ironisch-epische Sprache ist sehr reich  und verdient vom linguistischen Standpunkt aus Auf­ merksamkeit wegen ihres reichhaltigen lexischen und termino­ logischen Materials, insbesondere was die Bereiche der Tier­ welt und des Essens anbelangt.Die Weltanschauung des Dichters ist in dem ersten Fragment recht deutlich erkennbar. Da sieht man, dass er düster und pessimistisch auf das Leben blickt. Das Fehlen jeglicher positiven Einstellung hat dann den Sar­ kasmus zur Folge, mit dem der Dichter die Darstellung der Weiber einkleidet, ihn aber auch auf die Menschen schlechthin ausweitet.

  17. Verskuiwing in die moraal?

    S.P. van der Walt


    Full Text Available Modewoorde het ons deesdae oorgenoeg in die Christelike sedeleer en hulle kan nogal verwarring stig. U moet my vergun om met u te spreek oor een so ’n modewoord nl „verskuiwing’’ in die moraal. Dis nogal ’n mooi woord, wat so dikwels gebruik word op baie terreine en tog meer wil aandui as maar net ’n veranderde sienswyse, ’n wysiging in opvattinge of nuwe riglyne wat al gangbaar geword het in die praktyk. Die begrip wil eintlik die ewolusionêre gang beklemtoon, want dit is dan eintlik net die ou norme wat effens anders bekyk word of nie meer so nou geneem of dik onderstreep word nie. Die verskuiwing beteken dan dat alles nog dieselfde bly, net die posisie of plek het verander. Verskuiwing beteken tog plekverandering of plekwisseling en dan sekerlik nie in die sin dat die plekke ver uitmekaar lê nie. Verskuiwing beteken net maar vlak langs die vorige te staan kom. As dit dan ’n beter plek is, is dit ewolusie, ontwikkeling, verbetering.

  18. Die andersheid van Die verdwaalde land – die waarheid as storie vertel

    M. Hattingh


    Full Text Available Die verdwaalde land was written by Abraham Phillips, a so-called Coloured man from a South African working class background; someone who has no knowledge of literary conventions. The question arises: how can such a text be read without its uniqueness being affected by biased preconceptions? This article shows that post-structurally inspired theories on colonial discourse reveal perspectives on the complexity within the simplicity of this story. In this analysis of Die verdwaalde land particular emphasis is placed on identifying the framing strategies through which images and presentations of the Self and Other are created. Literary conventions are exposed as mechanisms which demarcate meaning, which in principle do not differ much from the manipulative strategies which define identity in the real world.Irrespective of nationality and time the line at which light race meets dark is the line at which human sociality is found at the lowest ebb; and wherever that line conies into existence there arc found the darkest shadows which we humans have cast by our injustice and egoism across the earth. (Olive Schreiner - Thoughts on South Africa

  19. Die karst-ekologie van die Bakwenagrot (Gauteng

    François Durand


    Full Text Available Die Bakwenagrot huisves ’n verskeidenheid organismes wat ’n ingewikkelde en verweefde voedselweb vorm. ’n Kolonie Natalse langvingervlermuise gebruik hierdie grot regdeur die jaar as blyplek. Die vlermuisguano en dooie plantmateriaal wat van buite in die grot inval, vorm die basis van die ekologie in die grot wat ook as ’n tipiese detritus-gedrewe ekostelsel beskryf kan word. Afbrekers soos bakterieë en swamme wat vir die afbraak van die guano en plantreste verantwoordelik is, word deur ’n verskeidenheid organismes, insluitend nematode en myte, as voedselbron benut. Hierdie organismes wat die volgende trofiese vlak vorm, word deur predatoriese artropode as voedselbron benut. Die Bakwenagrot is een van die weinige dolomietiese grotte in Suid-Afrika wat dit vir ‘n mens moontlik maak om tot by die grondwatervlak te kom. Die grondwater huisves verskeie tipes organismes waaronder bakterieë, swamme en diere – hoofsaaklik nematode en krustaseë. Die Bakwenagrot is ook die hoofvindplek waar varswater-amfipode in Suider-Afrika gevind is. Hierdie besondere en sensitiewe ekostelsel is hoofsaaklik van guano van die vlermuiskolonie afhanklik. Die grasveld in die gebied rondom die grot, wat as voedingsarea vir die vlermuiskolonie dien, word tans deur voorstedelike ontwikkeling en die gevolglike habitatfragmentasie en -vernietiging bedreig. Indien die vlermuise die grot sou verlaat, sal dit ’n hele domino-effek van uitsterwing van die grotbewonende organismes tot gevolg hê.

  20. Die voorgeskiedenis van kwantumberekening

    P. H. Potgieter


    Full Text Available

    Die hoofidees wat tans gestalte vind in die teorie en tegnologie van kwantumberekening is in die laat 1970’s en vroeg 1980’s deur fisici in die Weste en ’n wiskundige in die voormalige Sowjetunie neergelˆ e. Dat di´ e teorie ook wortels in die Russiestalige vakliteratuur het, is nie algemeen bekend in die Weste nie. Daar word kortliks gekyk na die idee soos deur Benioff en (veral Feynman in die Weste versprei, asook die voorstel van di´ e rekengrondslag deur Manin in die Russiese literatuur. Die outeur hoop om hiermee so ’n onpartydig moontlike sintese van die vroe ¨ e gedagtegeskiedenis rondom kwantumberekening aan te bied. Die rol van omkeerbare en onomkeerbare berekeningsprosesse word vlugtig bekyk soos dit verband hou met die ontstaan van kwantumberekening, asook die sogenaamde Inligtingsparadoks in die fisika. Die inligtingsteorie en die fisika het heelwat met mekaar te kommunikeer, soos hierdie paradoks uitwys.


    The pre-history of quantum computation

    The main ideas behind developments in the theory and technology of quantum computation were formulated in the late 1970s and early 1980s by two physicists in the West and a mathematician in the former Soviet Union. It is not generally known in the West that the subject has roots in the Russian technical literature. The idea, as propagated by Benioff and (especially Feynman, is reviewed along with the proposition of a foundation for this kind of computation by Manin in the Russian literature. The author hopes to present as impartial a synthesis as possible of the early history of thought on this subject. The role of reversible and irreversible computational processes will be examined briefly as it relates to the origins of quantum computing and the so-called Information Paradox in physics. Information theory and physics, as this paradox shows, have much to communicate to each other.

  1. Reengineering of Permanent Mould Casting with Lean Manufacturing Methods

    R. Władysiak


    Full Text Available At the work were introduced main areas of production system project of casts produced in permanent moulds, that constitutes reengineering of conventional production system according to Lean Manufacturing (LM methods. New resolution of cooling of dies with water mist was shown to casting of car wheels made from aluminium alloys in low pressure casting process. It was implemented as a part of goal-oriented project in R.H. Alurad Sp.z o.o. in Gorzyce. Its using intensifies solidification and self-cooling of casts shortening the time of casting cycle by the 30%. It was described reorganizing casting stations into multi-machines cells production and the process of their fast tool’s exchange with applying the SMED method. A project of the system was described controlling the production of the foundry with the computer aided light Kanban system. A visualization of the process was shown the production of casts with use the value stream mapping method. They proved that applying casting new method in the technology and LM methods allowed to eliminate down-times, to reduce the level of stocks, to increase the productivity and the flow of the castings production.

  2. Integration of CAD/CAE System for Casting Process Design

    周舰; 荆涛


    Concurrent engineering is needed to modernize the foundry industry and to reduce the scrap from castings and thus increase the economic profit. This paper presents an integrated 3-D CAD/CAE system for a foundry using concurrent engineering which considers casting structure, casting type, and manufacturing properties in the CAD module to design the pouring system, the riser, the chill core and so on. A visualized solid model is developed for the casting component with the model design enhanced by CAE analysis. Heat transfer and fluid flow simulation are used to analyze the initial design. The whole product development process is analyzed using concurrent engineering methods. The application shows that the integrated system can improve the efficiency of the design and manufacturing process of die casting.

  3. Research on Accuracy of Automatic System for Casting Measuring

    Jaworski J.


    Full Text Available Ensuring the required quality of castings is an important part of the production process. The quality control should be carried out in a fast and accurate way. These requirements can be met by the use of an optical measuring system installed on the arm of an industrial robot. In the article a methodology for assessing the quality of robotic measurement system to control certain feature of the casting, based on the analysis of repeatability and reproducibility is presented. It was shown that industrial robots equipped with optical measuring systems have the accuracy allowing their use in the process of dimensional control of castings manufactured by lost-wax process, permanent-mould casting, and pressure die-casting.


    Sabau, Adrian S [ORNL


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

  5. Die benutting van water in die landbou: strategie vir die toekoms

    D. S. van der Merwe


    Full Text Available ’n Uiteensetting word gegee van die faktore wat die hoofrol in die toekomstige waterbenutting in die landbou gaan speel. Hierdie faktore is die hoeveelheid water beskikbaar vir landboudoeleindes; die toenemende mineraiisasie van besproeiingswater; en die invloed wat energiebehoeftes op besproeiing sal hê. Navorsing is nodig om die situasie na wense te hanteer, en die aanbevelings van besproeiingsnavorsingswerksessies in hierdie verband word kortliks aangedui en bespreek.

  6. 电机机座铸件的消失模铸造%Lost Foam Casting for Motor Block Castings

    吴志超; 叶升平; 胡国良; 常湫生


    针对出口电机机座铸件,简要介绍了其消失模模具设计、成型发泡及铸件的浇注试验情况,确定了合适的铸造工艺参数,生产出了合格的铸件,证实了消失模铸造工艺生产电机机座铸件的可行性。%The design of lost foam die, pattern molding process, and pouring experiment of exported motor block casting were studied. The pertient casting technological parameters were determined. Qualified casting was made successfully, which testified the feasibility using lost foam casting to manufacture motor block casting.

  7. Cryogenic liquid hydrogen storage for the civil aviation. Impacts of variable ambient pressures; Kryogene Fluessigwasserstoffspeicher fuer die zivile Luftfahrt. Auswirkungen variabler Umgebungsdruecke

    Mock, Sebastian; Kabelac, Stephan [Helmut-Schmidt-Univ. / Univ. der Bundeswehr, Hamburg (Germany). Inst. fuer Thermodynamik


    If fuel cell systems are to be used as fuel in civilian aircraft, sufficient storage volumes must be available. Apart from safety and cost, low weight is one of the key requirements. The system weight of cryogenic liquid hydrogen stores depends, among others, on the pressures inside the store as these will directly affect the pressure vessel wall thickness. The liquid hydrogen store supplies the fuel cell with hydrogen at a defined pre-pressure. This is not the design-relevant maximum possible pressure, which is limited by relief and safety valves. The pressure levels in the system are composed of different fractions, e.g. pressure losses and pressure fluctuations in the system, as well as the safety factors for the safety valves. The maximum pressure should be kept as low as possible in order to minimize the system weight. The relief and safety valves are differential pressure valves that open at a defined pressure relative to ambient pressure. In aviation, there is the problem that the ambient pressure varies between about 1,02 bar(a) on the ground and 0.18 bar(a) in flight. If systems are designed as for ground applications, there is the problem that the required hydrogen pressure cannot be maintained in flight as the relief valves will open already at lower pressures. To prevent this, the permissible pressure levels and safety factor must be defined for in-flight applications. The contribution describes the proposed liquid hydrogen storage concept for in-flight applications and develops a definition for defining pressure levels and safety factors for cryogenic liquid hydrogen stores in aviation in consideration of the pertinent standards and technical rules. [German] Der Einsatz von Brennstoffzellensystemen in zivilen Flugzeugen erfordert nach derzeitigem Entwicklungsstand die Speicherung ausreichender Wasserstoffmengen an Bord, welcher dem System als Kraftstoff dient. Neben der Sicherheit und den Kosten ist ein geringes Gewicht eine der wichtigsten

  8. Openbaring, teologie en die regswetenskap

    S. Postma


    Full Text Available In die jongste tyd is telkens en weer gewaarsku teen die gevare van oorspesialisasie en die hipertrofie van professionalisme. Die gemis aan ’n totaliteitsvisie wat hiermee gepaard gaan, word dan ook tereg teengegaan en wel deur aan die Wysbegeerte as die Wetenskap van die totaliteit van die kosmos in toenemende mate sy regmatige plek as wetenskapsintegreerder te gun. Hierdie grootmoedige gun van ’n plek in die son van geleerdheid kan egter ook uit bedenklike motiewe plaasvind. Die vakwetenskaplike kan nie of wil nie die plek en betekenis van sy spesifieke vak bepaal en bepeins nie en vind dit in elk geval moeilik om die verband tussen Gods Woord en sy besondere vak in duidelike perspektief te sien; vandaar dan ’n grootmoedige toelaat dat die wysbegeerte die „veritas” dien terwyl die eie ek tevrede is om die „utilitas” onderdanig te wees.

  9. Die tug oor ampsdraers tydens die doleansie van 1886

    J. Visser


    Full Text Available In art 29 van die Nederlandse Geloofsbelydenis word bely: “Die merktekens om die ware Kerk te ken is die volgende: As die Kerk die suiwere prediking van die evangelie uitoefen, as dit die suiwer bediening van die sakramente gebruik soos Christus dit ingestel het, as die kerklike tug gebruik word om die sondes te straf.” Dit spreek vanself dat wanneer ampsdraers, aan wie Christus sy kudde toevertrou het (Hand 20 : 28, met leer en /of lewenswandel in sonde volhard en nie daarin met tug gestuit word nie, word die ware kerk nie gebou nie maar afgebreek. 0ns sal later in hierdie artikel aantoon hoedanig die suiwer tug oor ampsdraers, veral leertug, tydens die Doleansie tot skade van die kerk van Christus agterweë gebly het.

  10. Glovebox Advanced Casting System Casting Optimization

    Fielding, Randall Sidney [Idaho National Lab. (INL), Idaho Falls, ID (United States)


    Casting optimization in the GACS included three broad areas; casting of U-10Zr pins, incorporation of an integral FCCI barrier, and development of a permanent crucible coating. U-10Zr casting was improved over last year’s results by modifying the crucible design to minimize contact with the colder mold. Through these modifications casting of a three pin batch was successful. Incorporation of an integral FCCI barrier also was optimized through furnace chamber pressure changes during the casting cycle to reduce gas pressures in the mold cavities which led to three full length pins being cast which incorporated FCCI barriers of three different thicknesses. Permanent crucible coatings were tested against a base case; 1500°C for 10 minutes in a U-20Pu-10Zr molten alloy. None of the candidate coating materials showed evidence of failure upon initial visual examination. In all areas of work a large amount of characterization will be needed to fully determine the effects of the optimization activities. The characterization activities and future work will occur next year.

  11. Hemofilie onder die nasate van koningin Victoria

    Francois P. Retief


    Full Text Available Hierdie studie bespreek die uitwerking van die sogenaamde Victoriaanse hemofilie op Europese koningshuise gedurende die negentiende en twintigste eeu. Hemofilie as molekulêre defek word verduidelik en die kliniese beeld van die siekte word aangedui. ’n Bespreking van toepaslike terapeutiese ingrepe volg. Dan word ’n historiese oorsig verskaf van die verspreiding van Victoriaanse hemofilie vanaf koningin Victoria (Britse monarg, 1837–1901 via sommige van haar dogters na ander lede van die Britse koningshuis en ook na die Duitse, Russiese en Spaanse koningshuise. Elf bevestigde gevalle van hemofilie onder lede van koningin Victoria se nageslag word vermeld, asook drie ander moontlike gevalle van die siekte. Die effek van hemofilie op die verloop van die geskiedenis word ook ondersoek.Haemophilia amongst the descendants of Queen Victoria. This study discusses the impact of ‘Victorian haemophilia’ on the royal houses of Europe during the 19th and 20th centuries. Haemophilia as a molecular defect is explained and the clinical picture of the condition is indicated. Applicable therapeutic interventions also receive attention. Next, an historical review is provided of how ‘Victorian haemophilia’ spread from Queen Victoria (British monarch, 1837–1901 via some of her daughters to other members of the British royal family and also to the royal houses of Germany, Russia and Spain. Eleven confirmed cases of haemophilia amongst the descendants of Queen Victoria are mentioned, as well as three other possible cases. The effect of haemophilia on the course of history is also investigated.

  12. Die sterwende kindjie

    J.T. De Jongh van Arkel


    Full Text Available The thought of a child dying appears as an antithesis and thus the feelings evoked by the dying child are stronger than when older persons are dying. Around the child’s death bed there is no place for detached spectators and all become involved in caring for and supporting him. Caregivers also have a supporting responsibility towards the members of the child’s family.

  13. Ontsporing van die regstaatsbegrip en sy konsekwensies vir die afrikanervolk

    N. G.S. Van der Walt


    Full Text Available Die opvatting van die suiwere regstaat bring sy vraagstukke mee wanneer dit in verband gebring word met die leer van die soewereiniteit in eie kring. Laasgenoemde leer wortel in die geloof dat God die mens roep tot diens aan Hom, en dat die mens vry moet wees om ten opsigte van alle lewensaspekte God na die hoogste mate te kan dien. Hierdie verskeidenheid van aspekte is deur dr. A. Kuyper en sy volgelinge gesistemati- seer tot menslike verbande en lewenskringe, elk met ’n be- paalde sfeer waarin ander kringe nie mag inmeng nie. Elkeen is dan soewerein binne sy eie kring. Met verwysing na die staat is dan gespreek van die staatstaak as synde die hand- hawing van die reg, en omdat die staat in toenemende mate hom veral in die latere tyd ook besig gehou het met bedrywig- hede wat nouliks as van juridiese aard beskou kan word, is daar die onderskeid gemaak tussen die primêre en sekundêre taak van die staat. Die sistematiek van die wetsidee, deur prof. Dooyeweerd ontwikkel, waar die staat sy bestemmingsfunksie in die regsaspek vind, het vanselfsprekend geen plek vir so 'n dualistiese staatstaak nie, en die oplossing is deur sommige daarin gesoek om sulke staatsoptrede te vertolk as hebbende wel betrekking op die regsgemeenskap of die regsverkeer. Staatsondernemings soos paaie, spoorweë, spellingreëling, ens. word dan beskou as noodsaaklik vir die instandhouding van die regsgemeenskap en regsverkeer. Tereg wys A. M. Donner1 daarop dat so ’n vertolking eintlik neerkom op ’n oorspanning van die regsbegrip. Hy self sien dan die staatstaak in vrede- of orde-handhawing, wat in die eerste plaas wel regshandha- wing veronderstel. Onder orde word dan alles verstaan wat noodsaaklik is vir die gladde verkeer in die ontwikkelingsgang van die regsgemeenskap. Die wese van die staat het dan vol- gens hom te doen met reg, maar sy taak is meer as suiwere regshandhawing. Wat onrus verwek en die orde versteur, moet uit die openbare lewe verwyder word, en die

  14. Analise van die Tswanaraaisel

    S. A. Swanepoel


    Full Text Available ’n Strukturele, stilistiese en funksionele bcskrywing van die Twanaraaisel bring mee dat daar aan die volgende aspekte aandag gegee moet word: •\tWat is ’n raaisel en lioe word dit in Tswana genoem. •\tTot watter studiegebied en literere genre hoort die raaisel en watter subvorme kan vir Tswana onderskei word. •\tHoe sien die struktuur van Tswanaraaisels daar uit. •\tDeur wie, waar, wanneer en hoe word Tswanaraaisels voorgedra. •\tWatter stilistiese kenmcrke kan in Tswanaraaisels onderskei word. •\tWatter funksies vervul raaisels in ’n Tswanagcmeenskap.

  15. Improving Metal Casting Process


    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.

  16. Die brein soos beskou deur die Grieke en Romeine

    Francois P. Retief


    Full Text Available In Ou Egipte is mummifikasie met uitgebreide reseksie of uitsnyding van organe geassosieer, maar geen kennis is geneem van die morfologie van die brein nie. Griekse skrywers van die sesde en vyfde eeue v.C. het die brein aanvanklik gesien as die setel van intelligensie, die orgaan van sensoriese waarneming en gedeeltelik die oorsprong van sperma. Pneuma het ’n belangrike rol in breinfunksie gespeel. Hippokrates was die eerste om die brein te beskryf as ’n dubbele orgaan, wat met harsingvlies (meninges bedek, funksioneel van pneuma afhanklik en vertolker van begrip is. Tydgenote soos Plato, Aristoteles en Diokles het tot die beskrywing bygedra, maar laasgenoemde twee het beweer dat die hart die middelpunt van intelligensie is en nie die brein nie. Gedurende die laaste helfte van die vierde eeu v.C. is disseksie van die menslike liggaam tydelik aan die mediese skool van Alexandrië toegelaat en het dit tot merkwaardige vooruitgang in die begrip van die menslike anatomie en fisiologie gelei. Herofilus en Erasistratus het uitstekende beskrywings van die struktuur en funksie van die brein gegee wat eers in die tweede eeu n.C. deur Galenus geëwenaar is.


    Henrik Jesperson


    Full Text Available Gross cracking of die-casting dies with inferior toughness sometimes occurs through too low preheating temperature and/or too slow cooling during quenching. This study aimed to clarify the influence of cooling rate on the toughness of the hot-work tool steel grade Uddeholm Vidar Superior at ambient temperature and at 200 °C, a typical preheating temperature for aluminium die-casting dies. Toughness was measured through instrumented Charpy V-notch impact testing. The decrease in energy absorption with increasing cooling time between 800°C and 500°C both at both ambient temperature and 200 °C was pronounced. At ambient temperature, the decrease in total energy was a consequence of a decrease in initiation energy whereas, at 200 °C, the decrease in total energy was due to a decrease in propagation energy.

  18. Performance Steel Castings


    alloys , foundry, muzzle brake, supply center, tooling, sources Notice Distribution Statement A Format Information Report created in Microsoft Word...Development of Sand Properties 103 Advanced Modeling Dataset.. 105 High Strength Low Alloy (HSLA) Steels 107 Steel Casting and Engineering Support...University, University of Northern Iowa, Non- Ferrous Founders’ Society, QuesTek,, Spokane Industries, Nova Precision Casting, Waukesha

  19. Impact of climate change on the composition of the flora in salt marshes and coastal dunes. Final report; Auswirkungen von Veraenderungen klimatischer Bedingungen auf die Zusammensetzung der Flora in Salzwiesen und Kuestenduenen. Schlussbericht

    Gerlach, A.; Metzing, D.


    Aim of the present study was to evaluate the impact of changed climatic conditions to the areas of selected coastal plant species. Data on records and ranges of 225 plant species occurring in coastal ecosystems in Germany are taken from literature, herbarium specimens and available data files for the period of the last 200 years. The spatial and temporal patterns are presented in maps for particular species and time periods. To evaluate the climatic sensibility of particular plant species, climatic data as temperature and precipitation values for the European respectively German areas are extracted from climatic maps and data files. For further analysis the data are processed using GIS and statistical methods. Correlation of distribution patterns and climatic data allows a prediction of area dislocations caused by climatic change in some cases, but there is no evidence that the climatic change will affect the principal structure and appearance of the vegetation of salt marshes and dunes. The occurrence of most of the dominating species will not be affected by increasing temperature. An exception is the heath building Empetrum nigrum of the older island dunes. The probable decrease of this species may be a critical factor for the future stability of brown dune ecosystems. Additionally there will be slight changes in floral composition: boreal species may disappear locally, whereas mediterranean-atlantic species may expand their area to the German coasts. The presented results provide the fundamentals for further studies as monitoring projects or detailed aut- and synecological experiments. (orig.) [German] Ziel der vorliegenden Studie war, den Einfluss veraenderter klimatischer Bedingungen auf die Areale ausgewaehlter Gefaesspflanzenarten zu bewerten. Funddaten von 225 in Kuestenoekosystemen Deutschlands vorkommenden Pflanzentaxa wurden aus der Literatur, Herbarien und Datenbanken fuer den Zeitabschnitt der letzten 200 Jahre uebernommen. Die raumzeitlichen Muster

  20. Effects of silicon content and austempering condition on the impact characteristics of austempered ductile cast iron. Kyojin kyujo kokuen chutetsu no jinsei ni oyobosu osutenpa shori joken to Si ryo no eikyo

    Aoyama, M. (Daido Inst. of Technology, Nagoya (Japan)); Kobayashi, T. (Toyohashi Univ. of Technology, Aichi (Japan)); Matsuo, K. (Kurimoto Iron Works, Ltd., Osaka (Japan))


    Austempered spherical graphite cast iron (ADI) is extensively expeted as a mechanical structural material because of high tenacity and resilience as well as fatigue strength and wear resistance. These excellent properties are attributed to the abundantly remaining austenite because the formation of carbides is restricted by the action of the silicon element. It is, therefore, important for obtaining the strong cast iron material to control the amount of the retained austenite. In this study, the impact characteristics was investigated for acquiring the basic materials concerning the influence of the temperature, time of austempering and the amount of silicon. The added amount of silicon is most suitably 2.1%. Samples without Mn and Ni showed an impact value of about 2 times of the amount added. At 400 {degree} C, however, the impact value reduced to half by the growth of coarse ferrite and bentonite. Time of austempering was 1 hour and showed a stable impact value and load of breaking. Transition temperature shifted tolow side by the increase of amount of silicon. 14 refs., 10 figs., 1 tab.

  1. Prediking oor die poëtiese stof van die Ou Testament - Die Psalms

    E. J. Smit


    Full Text Available ’n Belangrike rede waarom die prediking uit die Psalms ’n aparte bespreking regverdig, is die feit dat die Psalms die omvangrykste verteenwoordiging van poetiese stof in die Ou Testament be vat. Dit is nie vir almal ewe maklik om poesie te lees en te verklaar nie.

  2. Evolution of halictine castes

    Knerer, Gerd


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

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

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


    The objective of this study was to improve average die life by optimizing die steel composition and the die processing. Four different steels, K,Q,C and Premium Grade H-13 have been investigated for thermal fatigue resistance and toughness. Optimum heat treatment processing has been determined for each steel with respect to austenitizing temperature and tempering conditions. The effect of the quenching rate on the thermal fatigue resistance and toughness of the die steels and the effect of Electro-Discharge Machining (EDM) on the thermal fatigue resistance were also determined. The immersion thermal fatigue specimen developed at CWRU was used to determine the thermal fatigue resistance as characterized by the two parameters of average maximum crack length and total crack area. The Charpy V-notch impact test was used over a -100{degrees}F to 450{degrees}F testing temperature range to evaluate the toughness and the brittle-ductile transition behavior. K steel has been identified as superior in performance compared to Premium Grade H-13. Q and C provide lower toughness and thermal fatigue resistance than H-13. Faster cooling rates provide higher thermal fatigue resistance and toughness. Higher austenitizing temperatures such as 1925{degrees}F compared to 1875{degrees}F provide better thermal fatigue resistance, but lower austenitizing temperatures of 1875{degrees}F provide better toughness. Higher hardness improves thermal fatigue resistance, but reduces toughness. A minimum of Rc 46 hardness is desired for aluminum die casting dies. EDM reduces the thermal fatigue resistance compared to conventional machining operations. When the EDM process of multiple small steps of decreasing energy and post-EDM treatments are employed, the effect can be reduced to a very slight amount. Preliminary evidence of the superior performance of the K steel has been provided by ongoing field testing of inserts in multiple cavity dies.

  4. Die hebsugtige seekoei en Rooikappie: Die groteske in sprokies

    Dineke van der Walt


    Full Text Available Hierdie artikel bied ’n vergelykende lees van twee volksverhale wat ook as kinderverhale getipeer kan word (een vanuit Venda-folklore en die ander ’n populêre Europese narratief met die oog daarop om spesifieke ooreenkomste uit te lig – soos die eet van mensvleis, goedgelowige mense wat deur ‘n maskerspel om die bos gelei word en ander ‘onetiese’ en ‘immorele’ aktiwiteite. In Die hebsugtige seekoei boots die monster byvoorbeeld die stem van die jong seun na om sy suster te flous en toegang tot hulle hut te verkry, terwyl die wolf in Rooikappie op sy beurt die ouma flous om die huis te kan betree sodat hy later ook vir Rooikappie kan mislei. In albei stories word die jong meisies (asook Rooikappie se ouma deur ’n seekoei óf ’n wolf opgeëet. Soos gewoonlik in sprokies, word die slagoffers gered of ontsnap en die verhale het ’n gelukkige einde. Alhoewel dit absurd mag voorkom dat kinderverhale elemente van die groteske bevat, argumenteer ek dat dit inderdaad ’n bruikbare doel dien. Hierdie verhale betrek kinders nie net op ’n emosionele vlak nie (as gevolg van die skokwaarde van die groteske; die groteske dien ook as objek van fassinasie. Sodoende word die waarskuwingsboodskap in die verhale beter oorgedra en onthou deur die kinders.

  5. The impact of the Russian lobbying on the German and European energy policy. The case Gazprom; Die Auswirkung der russischen Lobbyarbeit auf die deutsche und europaeische Energiepolitik. Das Fallbeispiel Gazprom

    Milaqi, Bledar


    The author of the contribution under consideration reports on the relationship between Germany, the European Union and Gazprom (Moscow, Russia). The author supports the hypothesis that Gazprom pushes the idea of an immediate common European energy strategy by its activities and impacts the German and European energy policy. The aspects of the participation of the Russian politics in the strategic decision-making bodies of Gazprom in key situations are elucidated.

  6. Biofuel and food security. The impact of the EU politics on the production of food with the example of Brasilia; Biokraftstoff und Ernaehrungssicherheit. Die Auswirkungen der EU-Politik auf die Nahrungsmittelproduktion am Beispiel Brasilien

    Rudolf, Andrea


    The author of the book under consideration presents a detailed overview of the economic, environmental and social consequences as well as the prospects of increased cultivation of biofuel in the European Union and Brazil and their impact on the bilateral relations. The associated risks and opportunities are identified. The author reports on how much our globalized world is dependent on ecologically and economically sustainable approach.

  7. Where do the elderly die? The impact of nursing home utilisation on the place of death. Observations from a mortality cohort study in Flanders

    Van Hecke Ettiene


    Full Text Available Abstract Background Most of the research concerning place of death focuses on terminally ill patients (cancer patients while the determinants of place of death of the elderly of the general population are not intensively studied. Studies showed the influence of gender, age, social-economical status and living arrangements on the place of death, but a facet not taken into account so far is the influence of the availability of nursing homes. Methods We conducted a survey of deaths, between January 1999 and December 2000 in a small densely populated area in Belgium, with a high availability of nursing homes (within 5 to 10 km of the place of residence of every elderly. We determined the incidence of total mortality (of subjects >60 years from local official death registers that we consulted via the priest or the mortician of the local parish, to ask where the decedent had died and whether the deceased had lived in a nursing home. We compared the distribution of the places of death between parishes with a nursing home and with parishes without nursing home. Results 240 women and 217 men died during the two years study period. Only 22% died at home, while the majority (78% died in an institutional setting, either a hospital (50% or a nursing home (28%. Place of death was influenced by individual factors (age and gender and the availability of a nursing home in the 'own' parish. The chance of in-hospital death was 65% higher for men (95% Confidence Interval [CI]: 14 to 138%; p = 0.008 and decreased by 4% (CI: -5.1% to -2.5%; p Conclusion Demographic, but especially social-contextual factors determine where elderly will end their life. The majority of elderly in Flanders die in an institution. Age, gender and living situation are predictors of the place of death but the embedment of a nursing home in the local community seems to be a key predictor.

  8. Caste in Itself, Caste and Class, or Caste in Class

    Ramkrishna Mukherjee


    After the British conquered Bengal and eventually the whole of India,they set out to administer the colony. In this context they encountered two phenomena with which they were not familiar: (1) the relation of people to land for production (and not for revenue receiving, household living, etc.), and (2) the caste system of India, viz. the jati strati?cation of society.

  9. Die entwicklung, die metamorphose, die entstehung: Die konzepte des organismus von Aristoteles bis Darwin

    Kamerer Eva


    Full Text Available (nemački In diesem Aufsatz versuche ich, die Elemente verschiedener Konzepte des Organismus in der Philosophie und in der Wissenschaft zu analysieren. Die Deutungen des Organismus und der Einheit der Natur bei Aristoteles, Kant und Goethe werden als ein Beispiel der Bewegung von einem finalistischen zum antifinalistischen Bild der Natur verstanden.

  10. Die Gattung Oerstedia

    Stiasny-Wijnhoff, G.


    Die vorliegenden Individuen von Oerstedia dorsalis (Abildg.) wurden in den Helder an der holländischen Küste gesammelt; die Art war in frühern Jahren im Hafen sehr allgemein. Sie lebte zwischen Tubularien und Muschelbrut, welche in der Gezeitenzone den Schiffsrümpfen angewachsen sind und enthielt im

  11. Die Mollusken der Njalindungschichten

    Martin, K.


    Die Versteinerungen, welche im folgenden behandelt sind, sammelten meine Frau und ich im Jahre 1910 in den Preanger-Regentschappen von Java, in der Gegend von Njalindung ¹). Sie stammen aus Sedimenten, für welche ich den Namen Njalindungschichten einführte, und für die Gastropoden wurde bereits eine

  12. Mandated political representation and crimes against the low castes

    Girard, Victoire


    Mandated political representation over the last twenty years has had a different impact on the reporting of crime by the low castes than what is observed for the reporting of crime by women. I exploit the timing of the implementation of mandated political representation of the low castes to examine its effect on crime reports by these people. Mandated political representation of the low castes in India appears to affect the declaration of crime only for two very specific crime categories: ide...

  13. Die oorsake vir die ontstaan en besondere aard van die Zion Christian Church

    M. A. Kruger


    Full Text Available Aanvanklik het die Z.C.C. geen opsienbarende groei getoon nie, maar veral sedert die veertigerjare het hulle getalle skerp toegeneem en versprei oor die hele land. In 1963 is Edward Lekganyane toegelaat tot die Stofberg Teologiese Skool van die N.G. Kerk. Sedert die stigting van die Z.C.C. het die groep al verder van die Woord af weg beweeg, maar met hierdie toetrede tot die skool het daar by Edward self ’n mate van verandering gekom.

  14. Evaluation of Cracking Causes of AlSi5Cu3 Alloy Castings

    Eperješi Š.


    Full Text Available Recently, the castings made from aluminum-silicon alloys by pressure die casting are increasingly used in the automotive industry. In practice, on these castings are high demands, mainly demands on quality of their structure, operating life and safety ensuring of their utilization. The AlSi5Cu3 alloy castings are widely used for production of car components. After the prescribed tests, the cracks and low mechanical properties have been identified for several castings of this alloy, which were produced by low pressure casting into a metal mould and subsequent they were heat treated. Therefore, analyses of the castings were realized to determine the causes of these defects. Evaluation of structure of the AlSi5Cu3 alloy and causes of failure were the subjects of investigation presented in this article.

  15. Application of optical scanning for measurements of castings and cores

    M. Wieczorowski


    Full Text Available In the paper application of non destructive method for dimensional control of elements in initial phase of car manufacturing, at Volks-wagen Poznań foundry was presented. VW foundry in Poznań is responsible of series production of chill and dies castings made of light alloys using contemporary technologies. Castings have a complex shape: they are die castings of housings for steering columns and gravity chill castings of cylinder heads, for which cores are manufactured using both hot box and cold box method. Manufacturing capabilities of VW foundry in Poznań reach 26.000 tons of aluminum castings per year. Optical system ATOS at Volkswagen Poznań foundry is used to digitize object and determination of all dimensions and shapes of inspected object. This technology is applied in car industry, reverse engineering, quality analysis and control and to solve many similar tasks. System is based on triangulation: sensor head projects different fringes patterns onto a measured object while scanner observes their trajectories using two cameras. Basing on optical transform equations a processing unit automatically and with a great accuracy calculates 3D coordinates for every pixel of camera. Depending on camera reso-lution as an effect of such a scan we obtain a cloud of up to 4 million points for every single measurement. In the paper examples of di-mensional analysis regarding castings and cores were presented.

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

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


    As a net shape process, die casting is intrinsically efficient and improvements in energy efficiency are strongly dependent on design and process improvements that reduce scrap rates so that more of the total consumed energy goes into acceptable, usable castings. A casting that is distorted and fails to meet specified dimensional requirements is typically remelted but this still results in a decrease in process yield, lost productivity, and increased energy consumption. This work focuses on developing, and expanding the use of, computer modeling methods that can be used to improve the dimensional accuracy of die castings and produce die designs and machine/die setups that reduce rejection rates due to dimensional issues. A major factor contributing to the dimensional inaccuracy of the casting is the elastic deformations of the die cavity caused by the thermo mechanical loads the dies are subjected to during normal operation. Although thermal and die cavity filling simulation are widely used in the industry, structural modeling of the die, particularly for managing part distortion, is not yet widely practiced. This may be due in part to the need to have a thorough understanding of the physical phenomenon involved in die distortion and the mathematical theory employed in the numerical models to efficiently model the die distortion phenomenon. Therefore, two of the goals of this work are to assist in efforts to expand the use of structural modeling and related technologies in the die casting industry by 1) providing a detailed modeling guideline and tutorial for those interested in developing the necessary skills and capability and 2) by developing simple meta-models that capture the results and experience gained from several years of die distortion research and can be used to predict key distortion phenomena of relevance to a die caster with a minimum of background and without the need for simulations. These objectives were met. A detailed modeling tutorial was

  17. Higher Education's Caste System

    Iannone, Ron


    In this article, the author discusses the history of the present caste system in higher education. He shows how the public's perception of this caste system is based on image and not usually on the quality of teaching and curriculum in colleges and universities. Finally, he discusses a model for accessibility to higher education and how higher…

  18. A cast orientation index.

    Ivanhoe, J R; Mahanna, G K


    This article describes a technique that allows multiple master casts to be precisely oriented to the same path of insertion and withdrawal. This technique is useful in situations where multiple fixed prosthodontic preparations require surveyed restorations and a single master cast is not available.

  19. Caste and power

    Roy, Dayabati


    This paper explores the institution of caste and its operation in a micro-level village setting of West Bengal, an Indian state, where state politics at grass roots level is vibrant with functioning local self-government and entrenched political parties. This ethnographic study reveals that caste...

  20. Tweedetaalteorie vir die eerstetaalonderwyser

    Ludolph Botha


    Full Text Available In hierdie artikel word die eerstetaalonderwyser se aandag op tweedetaalteorie gevestig. Krashen se tweedetaalteorie word uitgesonder en die implikasies van sy werk vir eerstetaalonderwysersword ondersoek. Die oordrewe beklemtoning van vormen struktuur in moedertaalklasse ( oor die taal praatl lees/ skryf word vanuit die gesigspunt van Krashen se taalverwerwingsteorie beskou en die gevolgtrekking word gemaak dat daar veel meer klem op gebruiksvaardigheid behoort te val (in die taal praat!lees!skryf. In this article the first language teacher is made aware of second language teaching theory. Particularly Krashen' s second language theory is referred to and implications of his work for mother tongue teachers are discussed. The over-emphasis on form and structure in first language classes (talking/reading/writing about the language is looked at in terms of Krashen' s theory and it is concluded that the emphasis in first language classes should be far more on the functional use of the language (talking/reading/writing in the language.

  1. Multi-layers castings

    J. Szajnar


    Full Text Available In paper is presented the possibility of making of multi-layers cast steel castings in result of connection of casting and welding coating technologies. First layer was composite surface layer on the basis of Fe-Cr-C alloy, which was put directly in founding process of cast carbon steel 200–450 with use of preparation of mould cavity method. Second layer were padding welds, which were put with use of TIG – Tungsten Inert Gas surfacing by welding technology with filler on Ni matrix, Ni and Co matrix with wolfram carbides WC and on the basis on Fe-Cr-C alloy, which has the same chemical composition with alloy, which was used for making of composite surface layer. Usability for industrial applications of surface layers of castings were estimated by criterion of hardness and abrasive wear resistance of type metal-mineral.

  2. Solidification process and infrared image characteristics of permanent mold castings

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


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

  3. Cast Iron And Mineral Cast Applied For Machine Tool Bed - Dynamic Behavior Analysis


    Cast iron and mineral cast are the materials most often used in the machine structural elements design (bodies, housings, machine tools beds etc.). The materials significantly differ in physical and mechanical properties. The ability to suppress vibration is one of the most important factors determining the dynamic properties of the machine and has a significant impact on the machining capabilities of a machine tool. Recent research and development trends show that there is a clear tendency t...

  4. Die kairos van die New Age: 'n Kultuurhistoriese skets

    the whole universe, manifesting the two aspects of spirit and matter, .... vestiging van die Christendom het hierdie leer uit die Westerse kultuur verdwyn tot- ... Hegel (1770-1831) het die Simboliste aangespreek (Mathews 1986:30-31, 33). Sy.

  5. Oor die einders van die bladsy as konseptuele kuns

    Rita M.C. Swanepoel


    Full Text Available Hierdie artikel bied ’n filosofies-besinnende oorsig oor konseptuele kuns. Ek argumenteer dat, soos wat die projek Oor die einders van die bladsy die grense van boekwees oorskry en konseptueel uitbrei, dit in geheel ’n konseptuele en taalgebaseerde kunsinstallasie is wat uit verskeie komponente, naamlik kunstenaarsboeke,bestaan. Hierdie saamgestelde konseptuele kunsinstallasie daag vanweë die interdissiplinêre aard daarvan, die grense van konseptuele kuns uit. Hierdie projek en uitstallings bevestig dat kunstenaarsboeke ’n ideale medium is om kunstenaars uit verskillende dissiplines by die spel met en ontdekking van die moontlikhede van die boek te betrek. Die projek kan in die geheel as konseptuele kuns getipeer word omdat die konsep boek herdink, herskep en oor gefilosofeer word.

  6. Die owerheidsinmenging met betrekking tot kerklike tughandelinge.

    L. Roeleveld


    Full Text Available Volgens art 29 NGB is die merktekens van die ware kerk die suiwere prediking van die Evangelie, die suiwere bediening van die Sakramente en die gebruik van die kerklike tug. Art. 32 NGB spreek uit dat die Kerkorde nie mag afwyk van wat Christus ingestel het nie. Menslike vindinge en wette om die gewetens te bind en te dwing, moet daarom verwerp word. Die ekskommunikasie of die ban moet toegepas word volgens die Woord van God.

  7. Die impak van tutoriale op die wiskundeprestasie van eerstejaarstudente

    J. G. Maree


    Full Text Available

    Studente uit histories-agtergeblewe gemeenskappe in Suid-Afrika onderpresteer dikwels in wiskunde vanweë ’n verskeidenheid faktore. Aksienavorsing wat aan die (voormalige Technikon Noord-Gauteng uitgevoer is, om ondersoek in te stel na wyses waarop hierdie studente se wiskundeprestasie verbeter kan word, het die implementering van ’n tutoriaalstelsel behels. Kwantitatiewe en kwalitatiewe data is deur middel van ’n verskeidenheid instrumente ingesamel. Die resultate het sekere tendense in tersiêre wiskundeonderrig, wat in ’n tweede of derde taal geskied, uitgewys.


    The impact of tutorials on achievement in mathematics of first year students

    Historically disadvantaged students in South Africa often underachieve in mathematics due to a number of factors. Action research that was conducted at the (former Technikon Northern Gauteng to investigate ways in which these students’ achievements in mathematics could be improved comprised the implementation of tutorial sessions. Quantitative and qualitative data were gathered by means of a variety of instruments. The results revealed certain trends in tertiary mathematics education where learning takes place in a second or third language.

  8. Growth of Legionella anisa in a model drinking water system to evaluate different shower outlets and the impact of cast iron rust.

    van der Lugt, Wilco; Euser, Sjoerd M; Bruin, Jacob P; Den Boer, Jeroen W; Walker, Jimmy T; Crespi, Sebastian


    Legionella continues to be a problem in water systems. This study investigated the influence of different shower mixer faucets, and the influence of the presence of cast iron rust from a drinking water system on the growth of Legionella. The research is conducted using a model of a household containing four drinking water systems. All four systems, which contained standard plumbing components including copper pipes and a water heater, were filled with unchlorinated drinking water. Furthermore, all systems had three different shower faucets: (A) a stainless-steel faucet, (B) a brass-ceramic faucet, and (C) a brass thermostatic faucet. System 1 was solely filled with drinking water. System 2 was filled with drinking water, and cast iron rust. System 3 was contaminated with Legionella, and system 4 was contaminated with a Legionella, and cast iron rust. During a period of 34 months, 450 cold water samples were taken from 15 sample points of the four drinking water systems, and tested for Legionella according to the Dutch Standard (NEN 6265). In system 4, with added cast iron rust, the stainless-steel mixer faucet (A) had the highest concentration of Legionella at >4.3log10CFU/l (>20,000CFU/l) and was positive in 46.4% of samples. In contrast, the stainless-steel mixer faucet (A) of system 3 without cast iron rust showed 14.3% positive samples with a maximum concentration of 3.9log10CFU/l (7600CFU/l) Legionella. Additionally, both contaminated systems (3 and 4), with the brass thermostatic faucet (C), tested positive for Legionella. System 3 in 85.7% of the samples, with a maximum concentration of 4.38log10CFU/l (24,200CFU/l), and system 4 in 64.3% of the samples with a maximum concentration of 4.13log10CFU/l (13.400CFU/l). These results suggest that both the type of faucet used in a drinking water system and the presence or absence of cast iron rust influence the growth of Legionella. Copyright © 2017 Elsevier GmbH. All rights reserved.

  9. Genetic evidence on the origins of Indian caste populations.

    Bamshad, M; Kivisild, T; Watkins, W S; Dixon, M E; Ricker, C E; Rao, B B; Naidu, J M; Prasad, B V; Reddy, P G; Rasanayagam, A; Papiha, S S; Villems, R; Redd, A J; Hammer, M F; Nguyen, S V; Carroll, M L; Batzer, M A; Jorde, L B


    The origins and affinities of the approximately 1 billion people living on the subcontinent of India have long been contested. This is owing, in part, to the many different waves of immigrants that have influenced the genetic structure of India. In the most recent of these waves, Indo-European-speaking people from West Eurasia entered India from the Northwest and diffused throughout the subcontinent. They purportedly admixed with or displaced indigenous Dravidic-speaking populations. Subsequently they may have established the Hindu caste system and placed themselves primarily in castes of higher rank. To explore the impact of West Eurasians on contemporary Indian caste populations, we compared mtDNA (400 bp of hypervariable region 1 and 14 restriction site polymorphisms) and Y-chromosome (20 biallelic polymorphisms and 5 short tandem repeats) variation in approximately 265 males from eight castes of different rank to approximately 750 Africans, Asians, Europeans, and other Indians. For maternally inherited mtDNA, each caste is most similar to Asians. However, 20%-30% of Indian mtDNA haplotypes belong to West Eurasian haplogroups, and the frequency of these haplotypes is proportional to caste rank, the highest frequency of West Eurasian haplotypes being found in the upper castes. In contrast, for paternally inherited Y-chromosome variation each caste is more similar to Europeans than to Asians. Moreover, the affinity to Europeans is proportionate to caste rank, the upper castes being most similar to Europeans, particularly East Europeans. These findings are consistent with greater West Eurasian male admixture with castes of higher rank. Nevertheless, the mitochondrial genome and the Y chromosome each represents only a single haploid locus and is more susceptible to large stochastic variation, bottlenecks, and selective sweeps. Thus, to increase the power of our analysis, we assayed 40 independent, biparentally inherited autosomal loci (1 LINE-1 and 39 Alu elements

  10. Excellent Casting Awards at the 2010 China International Foundry Expo

    China Foundry Association


    @@ The curtain has fallen on the 2010 China International Foundry Expo(CIFEX),which was held in the new Beijing International Exhibition Centre on May 11-14,2010.This Expo had a total exhibition area of 100,000 ㎡ in eight halls,each one being fully occupied.Hall E1 was for domestic,large-sized Casting and Forging Products; Hall E2 was devoted to domestic Die Casting and Nonferrous Casting; Hall E3 housed the Provincial Pavilions and Foundry Industrial Clusters; Hall E4 exhibited domestic Foundry Materials; Hall W1 was the International Hall for Foundry,Metallurgical,Casting and Refractory exhibits;Hall W2 contained domestic Metallurgical Products; Hall W3 exhibited domestic Metallurgical,Industrial Furnace and Refractory products,and Hall W4 contained domestic Foundry Equipment.

  11. Caste in Itself, Caste and Class, or Caste in Class

    Ramkrishna Mukherjee


    Full Text Available After the British conquered Bengal and eventually the whole of India,they set out to administer the colony. In this context they encountered two phenomena with which they were not familiar: (1 the relation of people to land for production (and not for revenue receiving, household living, etc., and (2 the caste system of India, viz. the jati strati?cation of society.

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

    Lee, Jonathan A.


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

  13. The ancient Chinese casting techniques

    Tan Derui


    Full Text Available In the course of Chinese civilization, which lasted more than 5,000 years, casting production has made a huge contribution. In this paper, some representative metal castings were presented. According to their forming techniques, they can be grouped into stone mould casting, clay mould casting, ablation casting, lost wax casting, stack casting, permanent mould casting, sand casting, etc. According to their materials, they can be categorized into tin bronze, bimetallic bronze, malleable cast iron, ductile cast iron, brass, cupronickel alloy (Packtong, etc. According to their surface decorative techniques they can be devided into gem inlay, gilding, gold and silver inlay, copper inlay, engraved decoration, surface tin-enrichment, mother-of-pearl inlay, burnished works with gold or silver inlay, surface coloring and cloisonné enamel, etc.

  14. Influence of Casting Conditions on Tribological Properties of A390.0 Alloy

    Piątkowski J.; Wieszała R.; Gontarczyk A.


    The paper presents tribological properties of A390.0 (AlSi17Cu5Mg) alloy coupled in abrasive action with EN-GJL-350 grey cast-iron. The silumin was prepared with the use of two different technologies which differed in terms of cooling speed. In the first case the alloy was modified with foundry alloy CuP10 and cast to a standard tester ATD and in case of second option the modified alloy was cast into steel casting die. Due to different speed of heat removal the silumins varied in structure, p...

  15. Microstructure and Property of Hypereutectic High Chromium Cast Iron Prepared by Slope Cooling Body-Centrifugal Casting Method

    Zhifu HUANG; Jiandong XING; Anfeng ZHANG


    In this paper, the ring-type ingot of hypereutectic high Cr cast iron was obtained by slope cooling bodycentrifugal casting method (SC-CCM), and its microstructure and impact toughness were investigated, respectively. The results indicated that, first, the primary carbides in the microstructure are prominently finer than those in the hypereutectic high Cr cast iron prepared by conventional casting method. Second, in the ring-type ingot, the primary carbides near radial outer field are finer than those near radial inner field; furthermore, there is dividing field in the microstructure. Finally, the impact toughness values of the specimens impacted on the radial outer face and on the radial inner face are improved respectively about 36% and 138%more than that of the hypereutectic high Cr one prepared by conventional casting method.

  16. State of the Art Treatment of Non-Ferrous Castings 3-in-1 Heat Treatment Systems Combine Foundry Processes

    Volker R. Knobloch


    The interior of a high-pressure die-casting is of an unsatisfactory quality. Engine blocks made with this die casting process show lower specific engine performance. Pressure die-casting can hardly be heat treated for obvious reasons.PSM (Precision Sand Molds) process uses sand and organic binder to generate a mold and even allows the manufacturing of complex diesel engine blocks in aluminum alloys. Combined technologies are available for semi-permanent mold castings with cores and castings made in Precision Sand Molds with organic binders. Castings are placed into the special heat treatment furnace immediately after pouring without the operations in stand alone machinery. This patented Sand Lion(R) 3-in-1 technology processes hot castings and carries out three (3) foundry processes simultaneously in one (1) automated machine: 1) De-coring and sand removal; 2) Thermal sand reclamation; 3) Solution heat treatment of castings. The combination of several main casting processes is reflected in significant reductions of energy consumption, of production costs, and improving the quality of the castings. Audits in foundries using the 3-in-1 process showed an average reduction in production costs of more than 30%.

  17. Die verband tussen die sielkundige kontrak en organisasieverbondenheid

    K. J. Stanz


    Full Text Available The relationship between the psychological contract and organisational commitment. The aim of this study is to design a measuring instrument with acceptable metric characteristics for the strength of the psychological contract within the South African context, and to determine empirically the relation between the strength of the psychological contract and organisational commitment. The Dhammanungune Model served as foundation for the design of the Strength of the Psychological Contract Questionnaire which consists of two scales namely, a needs expectation scale and a needs fulfilment expectation scale. The items of each scale have been formulated in the manner that ensures that the respondent reacts consecutively to two instructions namely, (a the level of the expectation and (b the importance of the expectation. This questionnaire was administered together with the Organisational Commitment Questionnaire to two population groups within the military environment. The Pearson Product Moment Correlation was calculated between the strength of the psychological contract and organisational commitment and the significance of the correlations was evaluated. Opsomming Die doel van die studie is om 'n meetinstrument met aanvaarbare metriese eienskappe vir die sterkte van die sielkundige kontrak vir Suid-Afrikaanse omstandighede te ontwerp en om empirics die verband tussen die sterkte van die sielkundige kontrak en organisasieverbondenheid te bepaal. Die sterkte van die sielkundige kontrak vraelys is op grond van die Dhammanungune-model ontwerp en het uit twee skale naamlik, die behoefteverwagting- en vervullingsverwagtingskale bestaan. Items vir eike skaal is sodanig geformuleer dat die respondent agteropeenvolgens op twee instruksies naamlik (a die vlak van die verwagting en (b die belangrikheid van die verwagting moet reageer. Die vraelys is saam met die organisasieverbondenheidsvraelys op twee populasies uit 'n militere omgewing toegepas. Die Pearson

  18. 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

    Manawar Ahmad


    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.

  19. Die postpolitische Stadt

    Erik Swyngedouw


    Full Text Available Die Polis ist tot, es lebe die kreative Stadt! Während die Stadt, zumindest in Teilen des städtischen Raums, blüht und gedeiht, scheint die Polis im idealisierten griechischen Sinn dem Untergang geweiht; in diesem Verständnis ist sie der Ort der öffentlichen politischen Auseinandersetzung und demokratischen Unterhandlung und somit eine Stätte (oft radikaler Abweichung und Unstimmigkeit, an der die politische Subjektivierung buchstäblich ihren Platz hat. Diese Figur einer entpolitisierten (oder postpolitischen und postdemokratischen Stadt im Spätkapitalismus bildet das Leitmotiv des vorliegenden Beitrags. Ich lehne mich dabei an Jacques Rancière, Slavoj Žižek, Chantal Mouffe, Mustafa Dikeç, Alain Badiou und andere Kritiker jenes zynischen Radikalismus an, der dafür gesorgt hat, dass eine kritische Theorie und eine radikale politische Praxis ohnmächtig und unfruchtbar vor jenen entpolitisierenden Gesten stehen, die in der polizeilichen Ordnung des zeitgenössischen neoliberalen Spätkapitalismus als Stadtentwicklungspolitik [urban policy] und städtische Politik [urban politics] gelten. Ziel meiner Intervention ist es, das Politische wieder in den Mittelpunkt der zeitgenössischen Debatten über das Urbane zu stellen. [...

  20. Magnesium - future material for automotive industry?; Magnesium - der Zukunftswerkstoff fuer die Automobilindustrie?

    Dieringa, H.; Kainer, K.U. [GKSS Forschungszentrum GmbH, MagIC - Magnesium Innovation Center, Geesthacht (Germany)


    Magnesium alloys show a very high potential in automotive applications as constructive metal, whereas the main focus lies on die cast parts. Electronic industry is the major commercial consumer for die castings besides the automobile industry. Room temperature applications like steering wheels and frame components in cars as well as mobile phone- or notebook housings are well established. These castings are produced with AZ- or AM-magnesium alloys, which show good room temperature properties and a good castability. The great alloy development challenge in extending the use of magnesium cast alloys are application for higher temperatures. The application in powertrain components is considered to be the benchmark here. Besides alloy development there are also further research activities in development of casting processes. Semi-solid processes like New-Rheocasting (NRC), Thoxomolding trademark or Thixocasting (TC) are adapted to the requirements of newly developed alloys. Not only cast alloys but also magnesium wrought alloys have moved to the centre of interest in the last decade. Alloy development for improving the formability on the one hand as well as process development in extrusion or rolling has to be done in order to find optimum parameters for deforming magnesium alloys properly. (Abstract Copyright [2007], Wiley Periodicals, Inc.) [German] Magnesiumlegierungen weisen ein sehr hohes Potential fuer den Einsatz als metallischen Konstruktionswerkstoff fuer die Automobilindustrie auf, wobei der Anwendungsschwerpunkt bei Druckgussbauteilen liegt. Neben der Automobilindustrie ist die Elektroniksparte der wichtigste Abnehmer fuer Druckgussteile aus Magnesiumlegierungen. Raumtemperaturanwendungen wie z. B. Lenkraeder und Rahmenteile im Automobil oder Handy- und Notebookgehaeuse sind industriell gut eingefuehrt. Sie werden aus Magnesiumlegierungen der AZ- oder AM-Familie gegossen, die mit ihren guten Raumtemperatureigenschaften und der guten Giessbarkeit die

  1. Die Anima in Eschenbachs Parzival

    Kitunen, S. (Sakari)


    In meiner Pro-Gradu -Arbeit untersuche ich die Darstellung und Entwicklung des Jungschen Animabegriffes im Parzival von Wolfram von Eschenbach. Ich werde die in Parzival vorkommenden Charaktere als Anima- und Animus-Figuren analysieren und untersuchen, wie die Interaktion zwischen ihnen die Entwicklung des Helden beeinflusst. Viele Werke, die das Thema Frauen bzw. Weiblichkeit im Mittelalter behandeln, gehen oft davon aus, dass die Frauen in der mittelalterlichen Literatur als Objekte behande...

  2. Influence of polyurethane resin dies on the fit and adaptation of full veneer crowns.

    Lillywhite, Graeme R R; Vohra, Fahim


    Polyurethane resin is a possible alternative to type IV dental stone for fabrication of indirect restorations however its dimensional accuracy is questionable. The aim was to investigate the dimensional accuracy of silica filled polyurethane resin die material by evaluating the marginal fit and adaptation of indirect gold castings. Experimental, in vitro study. Totally 40 copper plated replicas of a nickel chrome master die analogous to a veneer gold crown preparation were made and impressions recorded using polyvinylsiloxane material. Twenty impressions were poured in type IV dental stone (control group (Vel-mix, Kerr, UK) and the remaining (n = 20) in silica filled polyurethane die material (test group) (Alpha Die MF, CA, USA). Gold castings were fabricated for each die using standardized techniques. The castings were seated on their respective copper plated dies, embedded in resin and sectioned. The specimens were analyzed by measuring marginal opening and the area beneath the casting at a ×63 magnification and using image analysis software. Data were analyzed using a Student's t-test. No significant difference was observed between the experimental groups (P > 0.05). The mean marginal opening for type IV, dental stone and polyurethane resin, was 57 ± 22.6 μm and 63.47 ± 27.1 μm, respectively. Stone displayed a smaller area beneath the casting (31581 ± 16297 μm 2 ) as compared to polyurethane resin (35003 ± 23039 μm 2 ). The fit and adaptation of indirect gold castings made on polyurethane and type IV dental stone dies were comparable.

  3. Symptomatic stent cast.

    Keohane, John; Moore, Michael; O'Mahony, Seamus; Crosbie, Orla


    Biliary stent occlusion is a major complication of endoscopic stent insertion and results in repeat procedures. Various theories as to the etiology have been proposed, the most frequently studied is the attachment of gram negative bacteria within the stent. Several studies have shown prolongation of stent patency with antibiotic prophylaxis. We report the case of stent occlusion from a cast of a previously inserted straight biliary stent; a "stent cast" in an 86-year-old woman with obstructive jaundice. This was retrieved with the lithotrypter and she made an uneventful recovery. This is the first reported case of a biliary stent cast.


    Shuck, A.B.


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

  5. Symptomatic stent cast.

    Keohane, John


    Biliary stent occlusion is a major complication of endoscopic stent insertion and results in repeat procedures. Various theories as to the etiology have been proposed, the most frequently studied is the attachment of gram negative bacteria within the stent. Several studies have shown prolongation of stent patency with antibiotic prophylaxis. We report the case of stent occlusion from a cast of a previously inserted straight biliary stent; a "stent cast" in an 86-year-old woman with obstructive jaundice. This was retrieved with the lithotrypter and she made an uneventful recovery. This is the first reported case of a biliary stent cast.

  6. Die liefde wat die son beweeg en die ander sterre: Digterlike transendering – tot die vermenigvuldigde lewe ontroer

    A.S. (Rensia Robinson


    Full Text Available T.T. Cloete se oeuvre word onder andere gekenmerk deur fyn waarneming van ’n mistieke vervlegtheid in die skepping. Dit word op vele maniere ontgin en geïnterpreteer. Die poëtiese potensiaal van die vrou, in uiteenlopende gestaltes, is een van die sentrale temas waardeur die digter hieraan vorm gee. In die kunstige, bibliofiele uitgawe Uit die wit lig van my land gesny val die lig op die vrou se kreatiewe rol in die groter skepping wat haar onder andere identifiseer as haarveer vir digterlike insig en vormgewing. Vrou (alternatief Anna Perenna, universele moeder, is nie slegs draer van die lewenskiem wat tot gees transendeer nie, maar sy funksioneer as ligbron (’sonvrou’ wat selfs kosmiese insig verwesenlik. Dit raak meervoudige vorms en patrone waarin die mens ingeweef is in die universele hologram van lewe. Vir die digter is hierdie patroonvorming vergelykbaar met die maak van Persiese tapyte waarvan die patrone vasgelê is in die geheue van voorouers, en oorgedra word na opeenvolgende geslagte. In dié verkenning word digterlike transendering ontgin as ’n proses waarin die kleurvolheid van lewe en dood in en deur individuele sowel as universele vroulikheid geïnspireer word.

  7. Die liefde wat die son beweeg en die ander sterre: Digterlike transendering – tot die vermenigvuldigde lewe ontroer

    A.S. (Rensia Robinson


    Full Text Available T.T. Cloete se oeuvre word onder andere gekenmerk deur fyn waarneming van ’n mistieke vervlegtheid in die skepping. Dit word op vele maniere ontgin en geïnterpreteer. Die poëtiese potensiaal van die vrou, in uiteenlopende gestaltes, is een van die sentrale temas waardeur die digter hieraan vorm gee. In die kunstige, bibliofiele uitgawe Uit die wit lig van my land gesny val die lig op die vrou se kreatiewe rol in die groter skepping wat haar onder andere identifiseer as haarveer vir digterlike insig en vormgewing. Vrou (alternatief Anna Perenna, universele moeder, is nie slegs draer van die lewenskiem wat tot gees transendeer nie, maar sy funksioneer as ligbron (’sonvrou’ wat selfs kosmiese insig verwesenlik. Dit raak meervoudige vorms en patrone waarin die mens ingeweef is in die universele hologram van lewe. Vir die digter is hierdie patroonvorming vergelykbaar met die maak van Persiese tapyte waarvan die patrone vasgelê is in die geheue van voorouers, en oorgedra word na opeenvolgende geslagte. In dié verkenning word digterlike transendering ontgin as ’n proses waarin die kleurvolheid van lewe en dood in en deur individuele sowel as universele vroulikheid geïnspireer word.

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

    Robertson, E. [United States Air Force Academy, Colorado Springs, CO (US). Dept. of Engineering Mechanics


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

  9. Bainite obtaining in cast iron with carbides castings

    S. Pietrowski


    Full Text Available In these paper the possibility of upper and lower bainite obtaining in cast iron with carbides castings are presented. Conditions, when in cast iron with carbides castings during continuous free air cooling austenite transformation to upper bainite or its mixture with lower bainte proceeds, have been given. A mechanism of this transformation has been given, Si, Ni, Mn and Mo distribution in the eutectic cell has been tested and hardness of tested castings has been determined.

  10. Die histologie en ultrastruktuur van die hepatopankreas van die bloukurper Oreochromis mossambicus

    M. M. Nel


    Full Text Available Die histologie en ultrastruktuur van die hepatopankreas van die bloukurper Oreochromis mossambicus word beskryf. ’n Dun bindweefselkapsel omring die lewer. Die hepatosietrangskikking vertoon as lobules, met die koorde van hepatosiete wat vanaf ’n sentrale vene uitradieer en met mekaar anastomaseer. Indiwiduele lewerlohules vertoon nie duidelike grense nie, maar enkele duidelike triades word wel in die lewer van O. mossambicus aangetref. Die hepatosiete bevat ’n enkele ronde kern met ’n duidelike nukleolus en die growwe endoplasmiese retikula kom in twee of meer rye om die kerne en teen die selgrense van die hepatosiete voor. Die ander sitoplasmiese organelle kom verspreid in die hepatosietsitoplasma voor. Die eksokriene pankreasselle is om die portale venes gesetel. Die kerne van hierdie selle is rond en is hasaal in die kubies- tot silindervormige selle gelee. ’n Goedontwikkelde growwe endoplasmiese retikulum — vesikulêr, tubulêr en sirkulêr in vorm — en sektretoriese granules wat apikaal in die sel gelee is, kom voor.

  11. Colour Metallography of Cast Iron

    Zhou Jiyang; Liu Jincheng


    White Cast Iron (Ⅰ) White cast iron or ‘white iron' refers to the type of cast iron in which all of the carbon exists as carbide;there is no graphite in the as-cast structure and the fractured surface shows a white colour.White cast iron can be divided in three classes:· Normal white cast iron — this iron contains only C,Si,Mn,P and S,with no other alloying elements.· Low-alloy white cast iron — the total mass fraction of alloying elements is less than 5%.

  12. Diskussie oor die millenium en die herstel van Israel

    J. J. Engelbrecht van Waverley


    Full Text Available Dit verheug my dat daar eindelik gereageer word op my boekie. Behalwe telefoonoproepe en briewe van medechiliaste was daar tot dusver geen kommentaar van anti-chiliastiese kant. Ek het die boekie aan ongeveer 1800 predikante en professore gestuur en vriendelik uitgenooi tot nuwe besinning. Net soos oor die soteriologie, is die Bybel nêrens in teëspraak met homself oor die eskatologie nie. God gee in sy Woord nie vir ons drie verskillende toekomsbeelde om uit te kies nie. God is een en sy profetiese Woord is deurgaans eenstemmig m.b.t. die raad van God oor Israel, die nasies en die kerk.

  13. Die kerk en die kommunisme, uitgangspunt en perspektief

    A. H. Murray


    Full Text Available Waar ons onmiddellike opdrag is om die konkrete taak van die kerk in die bestryding van Kommunisme en Marxisme te beskrywe, is ons gedwing om terug te dink aan die eerste grondslae van die vyandelike aanslag — die grondslae waarop sy leer en sy beleid van gewelddadige optrede berus. Want ons het nie te doen met ’n opportunistiese onderneming of ’n imperialistiese waagstuk as dit oor die Kommunisme gaan nie, en ook nie met die blinde opbruising van laere en agterlike volksklasse nie, maar wel met ’n deurdagte en afgeronde heelal-filosofie wat oor die aardbol versprei is en wat op sistematiese wyse en met wetenskaplike strategie ’n aanval op die bestaande Christelike orde maak.

  14. Die Psychosen bei Epilepsie

    Glauninger G


    Full Text Available In einer Übersicht werden die verschiedenen Formen psychotischer Zustandsbilder bei Epilepsiepatienten, deren Ätiopathogenese und Möglichkeiten der Behandlung dieser Störungen beschrieben. Risikofaktoren finden sich durch neurobiologische Gegebenheiten - besonders bei Mitbeteiligung des Temporallappens, durch psychosoziale Einflüsse und manchmal auch durch medikamentöse Behandlung. Anhand von Fallbeispielen sollen dem Leser typische Krankheitsverläufe von psychotischen Episoden bei Epilepsiepatienten, die zumeist erst bei einer schon länger dauernden Epilepsie auftreten, nähergebracht werden. Es wird deutlich, daß sich die Beschwerden von Patienten mit Epilepsie nicht auf iktale Phänomene beschränken. Bei der Behandlung dieser Patienten kommt einer guten interdisziplinären Zusammenarbeit besondere Bedeutung zu.

  15. Wêreldgebeure gedurende die jaar 1954.

    S. du Toit


    Full Text Available Die jaar 1954 het begin sonder Stalin, die magtigste diktator van die modeme tyd, en dit wa s nog onseker hoe die nuwe regime sou optree.Teen die einde van die ja a r weet ons nou dat hulle oënskynlik meer toeskietlik is maar in wese nog net so geheimsinnig en nog net so geslepe. Die Petrof-gesjriedenis in Australië het weereens laat blyk dat daar oordie hele aarde ’n netwerk van spioene is.

  16. Olifantinvloed op Acacia Nigrescens-bome in 'n gedeelte van die Punda Milia- Sandveld van die Nasionale Krugerwildtuin

    A. H Engelbrecht


    Full Text Available Olifantinvloed op groot Acacia nigrescens (knop- piesdoring borne in die Punda Milia-Sandveld van die Nasionale Krugerwildtuin, is in Desernber 1978 ondersoek. 'n Monster van 951 borne toon dat die voortbestaan van die boornpopulasie bedreig word. Elephant impact on Acacia nigrescens trees in a section of the Punda Milia-Sandveld of the Kruger National Park. An investigation of elephant impact on tall Acacia nigrescens trees in the Punda Milia- Sandveld of the Kruger National Park was conducted during December 1978. A sample of 951 trees showed that the tree population is endangered.

  17. Die voorspelling van akademiese prestasie na die eerste universiteitsjaar

    G. K. Huysamen


    Full Text Available The prediction of academic performance after the first year at university. In agreement with findings elsewhere, the correlations of high school performance (Swedish Formula Point and the verbal and nonverbal GSAT scores with the mean percentage marks (MPMs gradually decreased from the first through sixth semester at university, whereas the decrease in the corresponding correlations with the cumulative mean percentage marks (CMPMs was less pronounced. The later the semester for which either an MPM or a CMPM was used as a predictor, the higher the latter tended to correlate with the MPMs of subsequent semesters but these correlations also decreased in size over the ensuing semesters. The best predictor of the MPM of any given semester was either the MPM of the immediately preceding semester or the CMPM of all the preceding semesters. Opsomming In ooreenstemming met bevindings elders, het die korrelasies van hoërskoolprestasie (Sweedse Formulepunt en verbale en nie-verbale ASAT-tellings met die gemiddelde persentasiepunte (GPP's geleidelik van die eerste tot die sesde semester op Universiteit afgeneem, terwyl die afname in die ooreenstemmende korrelasies met die kumulatiewe gemiddelde persentasiepunte (KGP's minder opvallend was. Hoe later die semester waarvan die GGP of KGP as voorspeller gebruik is, hoe hoër was dit geneig om met die GGP's van die daaropvolgende semesters te korreleer, maar die korrelasies het: eweneens met die toename in laasgenoemde semesters in grootte afgeneem. Die beste voorspeller van die GPP van enige gegewe semester was of die GPP van die pas afgelope semester, of die KGP van al die voorafgaande semesters.

  18. Precision Casting via Advanced Simulation and Manufacturing


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

  19. 50例舒缓患者音乐疗法生活质量影响观察%Observation of the impact of music therapy on the life quality of dying patients

    冷海燕; 吴玉华


    目的:探讨音乐疗法对临终患者生活质量的影响。方法:选择舒缓疗护病房100例患者,实验组和对照组各50例。对照组给予常规治疗及护理,实验组增加音乐疗法干预,每次30 min,1次/d。结果:两组患者心率、疼痛指标和远期生活质量比较差异有统计学意义(P<0.05);两组患者呼吸和血压指标差异无统计学意义。结论:音乐疗法能缓解舒缓患者疼痛症状,提高生活质量。%Objective:To explore the impact of music therapy on the life quality of dying patients. Methods:In the soothing palliative care wards 100 dying patients were selected and divided into the experiment group and the control group with 50 patients each. The control group received conventional treatment and care. The experiment group was added music therapy intervention 30 minutes each, once a day besides the conventional treatment and care. Results:The heart rate, pain index and long term life quality of the two groups were compared and their difference had statistical signiifcance (P<0.05). Their respiratory and blood pressure had no statistical difference. Conclusion:Music therapy can relieve the pain symptoms of dying patients and improve their life quality.

  20. Die Kunst des Scheiterns

    Juul, Jesper


    Menschen haben von Kindesbeinen an das Verlangen, Erfolge zu erzielen und Kompetenz zu erreichen. Computerspieler entscheiden sich jedoch fortlaufend für eine Aktivität, die oft und wiederholt zum Verlieren führen muss und ein taubes Gefühl der Unfähigkeit erzeugt. Im Kino, im Theatersaal und bei...

  1. Die skool en die onderwyser as faktore in die geestesgesondheid van die kind*

    B. C. Schutte


    Full Text Available Ons hou geestesgesondheidsweke, stig beroepsentrums, samel geld in om mense wat geestelik siek is te genees, klae oor die tekort aan psigiaters, kliniese sielkundiges, bedryfsielkundiges, voorligters, skoolpsigoloë,ens. ’n Karige kwarteeu gelede het ons aan al hierdie dinge slegs akademiese aandag gewy. In hierdie kursus wordverskeie tipes kinders bespreek en geleer hoe om hulle probleme te benader.

  2. Die Kunst des Scheiterns

    Juul, Jesper


    Menschen haben von Kindesbeinen an das Verlangen, Erfolge zu erzielen und Kompetenz zu erreichen. Computerspieler entscheiden sich jedoch fortlaufend für eine Aktivität, die oft und wiederholt zum Verlieren führen muss und ein taubes Gefühl der Unfähigkeit erzeugt. Im Kino, im Theatersaal und bei...

  3. Die Creol Taal

    Rossem, van Cefas; Voort, van der Hein


    Negerhollands is the original creole language, lexically closely related to Dutch, of the Virgin Islands. It emerged as a separate language around 1700 and died out completely only a few years ago, having gradually been replaced by English in the course of the nineteenth century. Apart from giving i

  4. Die andere Revolution

    Kippenhahn, Rudolf


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

  5. Die Kosmologie der Griechen.

    Mittelstraß, J.

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

  6. Internal adaptation of cast titanium crowns

    Sicknan Soares da Rocha


    Full Text Available As the adaptation of titanium crowns obtained by Rematitan Plus investment, specific for titanium, is not recognized to be suitable, this study evaluated the effect of the concentration of the specific liquid and the temperature of the mold of investments on the internal misfit of crowns cast on commercially pure titanium. Individual dies of epoxy resin were obtained, representing teeth prepared for full-crown restoration with a 6-degree axial surface convergence angle and shoulder (1.0 mm. For the waxing of each crown, a ring-shaped stainless steel matrix (8.0mm internal diameter; 7.5 mm height was adapted above the individual dies of epoxy resin. The Rematian Plus investment was mixed according to the manufacturer's instructions using two different concentrations of the specific liquid: 100%, 75%. Casting was performed in a Discovery Plasma Ar-arc vacuum-pressure casting machine with molds at temperatures of 430ºC, 515ºC and 600ºC. The crowns were cleaned individually in a solution (1% HF + 13% HNO3 for 10 min using a ultrasonic cleaner, with no internal adaptations, and luted with zinc phosphate cement under a 5 kg static load. The crown and die assemblies were embedded in resin and sectioned longitudinally. The area occupied by cement was observed using stereoscopic lens (10X and measured by the Leica Qwin image analysis system (mm². The data for each experimental condition (n=8 were analyzed by Kruskal-Wallis non-parametric test (á=0.05. The results showed that liquid dilution and the increase in mold temperature did not significantly influence the levels of internal fit of the cast titanium crowns. The lowest means (±SD of internal misfit were obtained for the 430ºC/100%: (7.25 mm² ±1.59 and 600ºC/100% (8.8 mm² ±2.25 groups, which presented statistically similar levels of internal misfit.

  7. Die ontwikkeling van 'n instrument vir die meting van die konstruk sielkundige diepte-orientasie

    L. C. De Jager


    Full Text Available The development of an instrument (the RD-Depth Questionnaire, Form B for measuring the construct psychological depth orientation is discussed. Results show that the questionnaire has satisfactory internal consistency and that the items of the questionnaire in general measure the same characteristic. Further research is needed to refine and improve the questionnaire until it meets all the psychometric requirements of a good measuring instrument.OpsommingDie ontwikkeling van 'n instrument (die RD-Diepte Vraelys, Vorm B vir die meting van die konstruk sielkundige diepteoriëntasie word bespreek. Resultate dui daarop dat die vraelys bevredigende interne bestendigheid toon en dat die items van die vraelys oor die algemeen dieselfde eienskap meet. Verdere navorsing word egter nog vereis om die vraelys te verfyn en te verbeter sodat dit aan al die psigometriese vereistes van 'n goeie meetinstrument sal voldoen.

  8. Die Wiege stand doch in Africka


    Kaum ein Forschungsgebiet ist so umstritten wie die Palaeoanthropologie, die Lehre yore Ursprung der Menschheit. Nicht nur die Vorgeschichte, ouch die unmittelbare Entstebung des Homo sapiens entzweit die Experten: Die einen verrnuten die Wiege in Afrika,die anderen gehen davon aus, dass sich tier moderne Mensch auf mehreren Kontinenten gleichzeifig aus Vorfahren eatwickelte,

  9. Development of casting process for large thin-wall precision magnesium alloy castings%大型薄壁精密镁合金铸件铸造技术进展

    王艳光; 彭晓东; 赵辉; 谢卫东; 魏群义


    The advantage and disadvantage as well as the development of sand casting, low tension casting, die casting, lost foam casting and centrifugal casting technologies for the production of large thin - wall precision magnesium alloy castings are discussed. According to the development of aerospace industry, the research and development direction of the magnesium alloy centrifugal casting are pointed out.%介绍了砂型、低压、压铸、消失模、离心铸造大型、薄壁、精密镁合金铸件的优势和缺点,以及这些铸造技术的最新发展情况.针对航天工业的发展指出离心铸造镁合金的研究与发展方向.

  10. Application of 3D stereoscopic visualization technology in casting aspect

    Kang Jinwu; Zhang Xiaopeng; Zhang Chi; Liu Baicheng


    3D stereoscopic visualization technology is coming into more and more common use in the field of entertainment, and this technology is also beginning to cut a striking ifgure in casting industry and scientiifc research. The history, fundamental principle, and devices of 3D stereoscopic visualization technology are reviewed in this paper. The authors’ research achievements on the 3D stereoscopic visualization technology in the modeling and simulation of the casting process are presented. This technology can be used for the observation of complex 3D solid models of castings and the simulated results of solidiifcation processes such as temperature, lfuid lfow, displacement, stress strain and microstructure, as wel as the predicted defects such as shrinkage/porosity, cracks, and deformation. It can also be used for other areas relating to 3D models, such as assembling of dies, cores, etc. Several cases are given to compare the illustration of simulated results by traditional images and red-blue 3D stereoscopic images. The spatial shape is observed better by the new method. The prospect of 3D stereoscopic visualization in the casting aspect is discussed as wel. The need for aided-viewing devices is stil the most prominent problem of 3D stereoscopic visualization technology. However, 3D stereoscopic visualization represents the tendency of visualization technology in the future; and as the problem is solved in the years ahead, great breakthroughs wil certainly be made for its application in casting design and modeling and simulation of the casting processes.

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

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


    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

  12. Die Tambaniprojek: ’n rekenaaranimasie van Die hebsugtige seekoei

    Rita M.C. Swanepoel


    Full Text Available Hierdie artikel bied ’n ondersoek na en refleksie op die tegnieke en die produksieprosesse wat gebruik is in die omskakeling van ’n tradisionele Ngano-Venda-volksverhaal, Die hebsugtige seekoei, vanaf borduurwerk in ’n digitale animasiefilm. Die artikel word gerig deur ’n metode wat afgelei is uit ’n praktykgebaseerde navorsingsmodel vir skeppende uitsette. Hierdie navorsingsmodel omskryf wyses waarvolgens skeppende uitsette as geldige navorsingsopsies gereken kan word. Die metode bestaan uit die dokumentering van en refleksie ten opsigte van die projek in drie fases, naamlik pre-produksie, produksie en post-produksie. Die Tambani-borduurwerkprojek is ’n gemeenskapsuitreikingsinisiatief wat deur Ina le Roux van stapel laat loop is. Ngano is die versamelwoord vir tradisionele Vendavolksverhale. In hierdie artikel argumenteer ons dat rekenaaranimasietegnieke wel suksesvol geïmplementeer word in die digitale omskakeling van ’n Venda-volksverhaal wat oorspronklik uit ’n mondelinge tradisie stam. Ons demonstreer hierdie argument aan die hand van Christiaan van der Westhuizen se omskakeling van Die hebsugtige seekoei in ’n rekenaaranimasie.

  13. Melt Cast High Explosives

    Stanisław Cudziło


    Full Text Available [b]Abstract[/b]. This paper reviews the current state and future developments of melt-cast high explosives. First the compositions, properties and methods of preparation of trinitrotoluene based (TNT conventional mixtures with aluminum, hexogen (RDX or octogen (HMX are described. In the newer, less sensitive explosive formulations, TNT is replaced with dinitroanisole (DNANDNANDNAN and nitrotriazolone (NTONTONTO, nitroguanidine (NG or ammonium perchlorate (AP are the replacement for RDRDX and HMX. Plasticized wax or polymer-based binder systems for melt castable explosives are also included. Hydroxyl terminated polybutadiene (HPTB is the binder of choice, but polyethylene glycol, and polycaprolactone with energetic plasticizers are also used. The most advanced melt-cast explosives are compositions containing energetic thermoplastic elastomers and novel highly energetic compounds (including nitrogen rich molecules in whose particles are nanosized and practically defect-less.[b]Keywords[/b]: melt-cast explosives, detonation parameters

  14. Die historiese betroubaarheid van die aartsvadervertellinge. 'n Beknopte bespreking van die huidige debat na aanleiding van die jongste publikasie

    W. Vosloo


    Full Text Available Die afgelope twintig jaar was daar �n toenemende belangstelling in die aartsvadervertellinge in Genesis. Benewens die talle tydskrifartikels het skrywers soos die volgende ook boeke oor die onderwerp die lig laat sien: A. Parrot (1962, W. M. Clark (1964, R. Kilian (1966, R. E. Clements (1967, N. Lohfink (1967, H. Weidemann (1968, R. Martin-Achard (1969, T. L. Thompson (1974, J. van Seters (1975, J. P. Fokkelman (1975, C. Westermann (1976, R. Rendtorff (1977, J. Bright (1977, W. McKane (1979 en A. R. Millard en D. J. Wiseman (1980.

  15. Herausforderungen durch die deutsche Wiedervereinigung

    Stäglin, Reiner

    Die Wiedervereinigung stellte auch die Statistik vor große Aufgaben. Die als Organ der staatlichen Planung staatsnah orientierte Statistik der DDR musste auf das zur Neutralität und wissenschaftlichen Unabhängigkeit verpflichtete System der Bundesrepublik umgestellt werden. Ebenso verlangten die Universitäten eine Neuorientierung. Die Deutsche Statistische Gesellschaft hat sich vor allem dreier Aufgaben mit großem Engagement, aber auch mit Bedachtsamkeit angenommen: Aufnahme und Integration der Statistiker aus den neuen Bundesländern in die Gesellschaft, Begleitung der Neuausrichtung des Faches Statistik an deren Hochschulen und Sicherung sowie Nutzung von Datenbeständen der ehemaligen DDR.

  16. Gedagtes oor die begin van die kerk - 'n geskiedenis van ...

    seriously, affirm, and thankfully acknowledge Christendom, the. Church. We must ... In all this we at least approached the theology and practice of a spiritual partisan ..... Hegel se geskiedsfilosofie hou juis 'sintese' voor as die eindpunt van die.

  17. Film Presentation: Die Urknallmaschine

    Carolyn Lee


    Die Urknallmaschine, an Austrian film by Gerd Baldauf, narrated by Norbert Frischauf (Alpha Österreich - ORF, 2009).  In CERN’s gigantic complex particles are accelerated to almost the speed of light, brought to collision and made to divide into even smaller particles. Public opinion of CERN’s research is also divided. Sceptics fear that black holes may be created. Might the goal to study the origin of the world lead to its destruction? The Austrian researcher Norbert Frischauf worked at CERN for many years. With his guidance it is possible to explore the world’s largest research centre, get a glimpse of the fascinating work the scientists do there and take a crash course in particle physics. Die Urknallmaschine will be presented on Friday, 25 June from 13:00 to 14:00 in the Main Auditorium. Language: German

  18. Dying for security

    Buchan, Bruce


    Full Text Available If political statements and media coverage are any guide, it seems Australians today are dying for security. At no other moment in our history has the spectre of war and terrorism so haunted popular, political and scholarly perceptions of Australia’s colonial past and of its geopolitical future. And yet, debates over colonial war or genocide and contemporary terrorism have been conducted in more or less complete isolation. In this article I argue that our contemporary obsession with ‘security’ is premised on the perennial threat of ‘insecurity’. This is the problem of in/security, and it has played a central role in the development of Western political thought. More importantly, its formulation in Western political thought provided a powerful justification for the violence of the early decades of Australia’s colonisation during which Indigenous Australians could also be said to have been dying for security.

  19. Dying for Security

    Bruce Buchan


    Full Text Available If political statements and media coverage are any guide, it seems Australians today are dying for security. At no other moment in our history has the spectre of war and terrorism so haunted popular, political and scholarly perceptions of Australia’s colonial past and of its geopolitical future. And yet, debates over colonial war or genocide and contemporary terrorism have been conducted in more or less complete isolation. In this article I argue that our contemporary obsession with ‘security’ is premised on the perennial threat of ‘insecurity’. This is the problem of in/security, and it has played a central role in the development of Western political thought. More importantly, its formulation in Western political thought provided a powerful justification for the violence of the early decades of Australia’s colonisation during which Indigenous Australians could also be said to have been dying for security.

  20. Dying from cardiac tamponade

    Powari Manish


    Full Text Available Abstract Background To determine the causes of cardiac tamponade (CT, focussing especially on haemopericardium (HP, as a terminal mode of death, within a 430,000 rural English population. Methods Our hospital mortuary register and, all postmortem reports between 1995 and 2004 inclusive, were interrogated for patients dying of CT or HP. The causes of CT/HP and selected morphological characteristics were then determined. Results 14,368 postmortems were performed in this period: of these, 461 patients died of CT. Three cases were due to non-haemorrhagic pericardial effusion. HP accounted for the remaining 458 cases of which, five were post-traumatic, 311 followed rupture of an acute myocardial infarction (RAMI, 138 after intra-pericardial rupture of dissecting ascending aortic aneurysms (RD3A and four were due to miscellaneous causes. HP was more commonly due to RAMI. Men tended to die from RAMI or RD3A earlier than women. RAMI or RD3A were commoner in men Two thirds of RAMI were associated with coronary artery thrombosis. Anterior free wall rupture was commonest overall, and in women, but posterior free wall rupture was commoner in men. The volume of intrapericardial blood in RAMI (mean = 440 ml and RD3A (mean = 498 ml varied between 150 and 1000 ml: intrapericardial blood volume was greater in men than in women dying from either RAMI or RD3A. Conclusion At postmortem, CT is most often related to HP, attributable to either RAMI or intrapericardial RD3A. Post-traumatic and other causes of CT are infrequent.

  1. Die medizinische Diskussion um die Fettleibigkeit 1800-1914

    Holstermann, Inga Kristine


    Gegenstand der Untersuchung ist die medizinische Diskussion um die Fettleibigkeit von 1800 bis 1914. Dargestellt werden die unterschiedlichen Betrachtungsweisen der Fettleibigkeit beeinflusst durch gesellschaftliche, industrielle und medizinische Entwicklungen im Untersuchungszeitraum unter den Aspekten der Ursachen (Lebensführung, erbliche Veranlagung, Geschlecht, Alter, Stoffwechselstörungen) und Folgen (Gesundheitsgefahren, Ästhetik, psychische Auswirkungen). Des weiteren werden Konzepte z...

  2. Die Leben Einsteins eine Reise durch die Geschichte der Physik



    Jeder kennt die Namen Einstein, Newton oder Galilei. aber was weiss man über sie? Hier ein Porträt Einsteins anhand von sechs Meilensteinen aus der Geschichte der Physik. Einstein tritt auf als Protagonist in verschiedenen Epochen und bei verschiedenen Entdeckungen, die die Welt verändert haben.

  3. Geslagsverskille in die ouditiewe ontlokte potensiaal van die brein

    Anita D Stuart


    Full Text Available Gender differences in the auditory evoked potential of the brain. Based on literature indications of an association between temperament characteristics and the evoked potential of the brain, and indications of gender differences in certain temperament traits, the purpose of this study was to ascertain whether evoked responses also differentiated between the genders. A sample of 81 male and 210 female students was randomly selected. Two auditory evoked potential procedures were applied. The results indicated statistically significant differences in evoked potential responses between the genders. The results are interpreted against the background of sensory and neurological sources of the evoked potential responses and linked to the neurophysiological foundations of temperament. Opsomming: Gegrond op aanduidings in die literatuur van ’n assosiasie tussen temperamentskenmerke en die ontlokte potensiaal van die brein, sowel as aanduidings van geslagsverskille in sekere temperamentstrekke, was die doel van die huidige studie om te bepaal of ontloktepotensiaal-response ook tussen die geslagte onderskei. ’n Steekproef van 81 manlike en 210 vroulike studente is ewekansig geselekteer. Twee ouditiewe ontloktepotensiaal- prosedures is toegepas. Die resultate het op statisties beduidende verskille tussen die geslagte gedui. Die bevindinge word teen die agtergrond van die sensoriese en neurologiese oorsprong van ontloktepotensiaal–response geïnterpreteer en verbind aan die neurofisiologiese verankering van temperament.


    Ali A Aljubouri


    Full Text Available   The die geometry has a massive effect on the plastic deformation behavior during pressing of material processed by equal channel angular pressing (ECAP method; subsequently the properties of the processed material are strongly dependent on it. Two categories of designed and manufactured dies are used for equal channel angular pressing, a 1200 sharp angle and a 900 round –cornered (200 dies, that produce strain per pass through both dies of ~0.7 and ~1.05   respectively. The microhardness developed in Al-Si alloy during ECAP using route BC. The microhardness increased by a factor of >1.5, after only 1 pressing. Subsequently, the hardness increases slightly up to 8 pressings through the 1200 sharp angle die, while it is increased by a factor of ~2.6 after 5 passes by using the 900 round cornered die, comparing with that for the cast workpiece.

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

    Lim Sang-Sub


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

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

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


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

  7. Colour Metallography of Cast Iron

    Zhou Jiyang; Ph.D Liu Jincheng


    @@ Note: This book consists of five sections: Chapter 1 Introduction, Chapter 2 Grey Iron, Chapter 3 Spheroidal Graphite Cast Iron, Chapter 4 Vermicular Cast Iron, and Chapter 5 White Cast Iron. CHINA FOUNDRY publishes this book in several parts serially, starting from the first issue of 2009.

  8. Evaluation of an improved centrifugal casting machine.

    Donovan, T E; White, L E


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

  9. Structural durability criteria for commercial vehicle components from the self strengthening cast ausferrite nodular iron EN-GJS-800-8 (ADI) in comparison to the ferritic EN-GJS-400-15

    Zinke, R.; Heinrietz, A.; Heim, R.; Hanselka, H. [Fraunhofer Institut fuer Betriebsfestigkeit LBF, Darmstadt (Germany); Streicher, M. [MAN Nutzfahrzeuge AG, Munich (Germany); Sonsino, C.M.


    The structural durability of safety components in the chassis comprises not only the fatigue behaviour under cyclic variable amplitude service loading, but also its interaction with prestrains caused by special events and the rupture behaviour under impact loading due to misuse. From this background, the structural durability behaviour of Panhard rods made from ferritic cast nodular iron EN-GJS-400-15 was compared with the behaviour of rods made from the austempered EN-GJS-800-8. The components investigated, Panhard rods and cast plugs, made from the austempered material revealed a higher impact resistance than the components made from the ferritic cast nodular iron. Due to their ausferrite microstructure, Panhard rods made from EN-GJS-800-8 display a significantly superior fatigue strength behaviour, especially under spectrum loading, and offer a potential for lightweight design. Prestrains do not affect the fatigue behaviour under variable amplitude loading and the plastic deformation of the component under impact loading can be increased by appropriate design reducing the stiffness in the shaft area and achieving a weight reduction by 15 %. (Abstract Copyright [2008], Wiley Periodicals, Inc.) [German] Die Betriebsfestigkeit von Fahrwerksbauteilen wird nicht nur von der Schwingfestigkeit unter zyklischen Betriebsbelastungen und Missbrauchsbelastungen bestimmt, sondern auch durch die Interaktion mit Sonderbelastungen und Missbrauchsbelastungen. Vor diesem Hintergrund wird anhand eines Panhard-Stabes, ein stabilisierendes Element im Fahrwerk von Nutzfahrzeugen, gezeigt, wie zunaechst durch eine Werkstoffsubstitution, naemlich des konventionellen Eisengraphitgusses EN-GJS-400-15 (GGG 40), durch die ADI (Ausferrite Ductile Iron)-Variante EN-GJS-800-8 mit der entsprechenden Waermebehandlung eine deutlich hoehere Schwingfestigkeit erzielt wird. Zu bemerken ist, dass der ADI-Guss gefuegebedingt gegenueber dem konventionellen ferritischen Werkstoff unter variablen

  10. Verrekening van die kragveld van die verbond in die inkleding van die kommunikatiewe driehoeksverhouding tussen teks, hoorder en prediker

    Friedrich W. de Wet


    Full Text Available In hierdie artikel word die kommunikatiewe driehoeksverhouding tussen die Bybelse teks, die hoorders en die prediker homileties verken. Die probleemstelling waarmee gewerk word handel oor potensiële versteurings wat kan plaasvind in hierdie driehoeksverhouding wanneer die hoorders en die prediker in hulle menslike beperktheid in verbinding gebring word met die ewige Woord van God soos dit in die Bybelse teks na vore kom. In die loop van die artikel word die volgende aspekte verken: ’n Ideale tipering van die verhouding tussen die teks, hoorders en prediker waarin al drie faktore ’n regmatige plek het; die maniere waarop die kommunikatiewe driehoek in die spanningsveld tussen teks, hoorders en prediker kan skeeftrek; en pneumatologiese verankering van die kommunikatiewe driehoek in die kragveld van die verbondsruimte, waarin Jesus Christus versoenend (integrerend teenwoordig is. Die gevolgtrekking waartoe gekom word, is dat die prediker in die kragveld van die verbond in staat gestel word om getrou te bly aan die teks (waarin God aan die Woord kom, aan die hoorders (as mededeelgenote in die genade van God sowel as – in missionêre konteks – mense wat geroep word om deelgenote in hierdie genade te word en aan hom- of haarself (as nuwe mens in Christus sonder dat die verbintenis aan een element in die  kommunikatiewe driehoek die verbintenis aan die ander versteur of laat disintegreer.Reckoning with the force field of the covenant in aligning the communicative triangle between text, listener and preacher. In this article the communicative triangular relationship between the Biblical text, the listeners and the preacher is reflected upon from a homiletic point of view. The problem statement deals with potential distortions in this triangular relationship when the listeners and preacher (in their human finitude are brought into contact with the eternal Word of God as it proceeds from the Biblical text. In the course of the article the

  11. ToxCast Dashboard

    The ToxCast Dashboard helps users examine high-throughput assay data to inform chemical safety decisions. To date, it has data on over 9,000 chemicals and information from more than 1,000 high-throughput assay endpoint components.

  12. Accuracy of Multiple Pour Cast from Various Elastomer Impression Methods

    Satheesh B. Haralur


    Full Text Available The accurate duplicate cast obtained from a single impression reduces the profession clinical time, patient inconvenience, and extra material cost. The stainless steel working cast model assembly consisting of two abutments and one pontic area was fabricated. Two sets of six each custom aluminum trays were fabricated, with five mm spacer and two mm spacer. The impression methods evaluated during the study were additional silicone putty reline (two steps, heavy-light body (one step, monophase (one step, and polyether (one step. Type IV gypsum casts were poured at the interval of one hour, 12 hours, 24 hours, and 48 hours. The resultant cast was measured with traveling microscope for the comparative dimensional accuracy. The data obtained were subjected to Analysis of Variance test at significance level <0.05. The die obtained from two-step putty reline impression techniques had the percentage of variation for the height −0.36 to −0.97%, while diameter was increased by 0.40–0.90%. The values for one-step heavy-light body impression dies, additional silicone monophase impressions, and polyether were −0.73 to −1.21%, −1.34%, and −1.46% for the height and 0.50–0.80%, 1.20%, and −1.30% for the width, respectively.

  13. Die amtliche Kinder- und Jugendhilfestatistik

    Schilling, Matthias


    Unter Rückgriff auf verschiedene wissenschaftliche Methoden umfasst die Dissertation eine differenzierte Untersuchung der amtlichen Kinder- und Jugendhilfestatistik (KJH-Statistik). Da die wissenschaftliche Sozialpädagogik erst langsam und zögerlich beginnt, die amtliche Statistik der Kinder- und Jugendhilfe wahrzunehmen, liegt das Forschungsinteresse darin, dass eine grundlegende und umfassende wissenschaftliche Analyse der Möglichkeiten und Grenzen der KJH-Statistik vorgenommen wird. Die KJ...

  14. The pressure relief impact's improvement research of 4000t-die-forging press%4000t模锻压机卸压冲击改进研究

    沈文奇; 湛利华; 黄明辉; 陈敏


    Because repeatedly debugging the unloading way wastes time and energy ,using only one fixed unloading way to deal with the 4000t-die-forging press which works under different working conditions ,leads to apparently shock vibration .In order to maintain the press’s hardware and optimize the unloading control mode to get the best unloading effect in different initial unloading pressures ,we put forward a way that deduced the shock-free unloading curve based on the mech-anism of pressure relief ,then got the voltage control mode through converse modeling and simu-lation .The results show that ,the optimal way to release the energy pressure is in the sine way , and in the same way we get the other voltage control mode under different initial pressures when the energy is released in the sine way .This research provides a theoretical guidance for engineer-ing practice and provides a reference for operation in the factory .%4000 t模锻压机在不同工况(工作缸压力变化较大)下,反复调试卸压方式费时费力,所以基本采用一种默认的方式卸压,导致实际操作中卸压冲击振动现象比较明显。为了尽可能保持压机硬件设施不变,采取优化卸压控制方式来达到不同初始卸压压力下都能有较好的卸压效果,基于卸压冲击机理推导出工作缸无冲击的理想卸压曲线,然后利用逆向建模法仿真得出理想卸压曲线下的控制方式,并通过实验对比分析得出以能量正弦释放的卸压方式是最优卸压方式,从而根据同样的方法得出以能量正弦释放的卸压方式在其他初始卸压压力下的控制信号,为工程实践中卸压操作提供了理论指导和参考。

  15. Control of cast iron and casts manufacturing by Inmold method

    S. Pietrowski


    Full Text Available In this paper the usability of cast iron spheroidizing process in mould control by ATD method as well as by ultrasonic method were presented. Structure of instrumentation needed for control form performance of cast iron spheroidizing by Inmold method was illustrated. Author, pointed out that amount of magnesium master alloy should obtain 0,8 ÷ 1,0% of mass in form at all. Such quantity of preliminary alloy assure of obtain of nodular graphite in cast iron. In consequence of this, is reduce the cast iron liquidus temperature and decrease of recalescence temperature of graphite-eutectic crystallization in compare with initial cast iron. Control of casts can be carried out by ultrasonic method. In plain cast iron, ferritic-pearlitic microstructure is obtaining. Additives of 1,5% Cu ensure pearlitic structure.

  16. Precision die design by the die expansion method

    Ibhadode, A O Akii


    This book presents a new method for the design of the precision dies used in cold-forging, extrusion and drawing processes. The method is based upon die expansion, and attempts to provide a clear-cut theoretical basis for the selection of critical die dimensions for this group of precision dies when the tolerance on product diameter (or thickness) is specified. It also presents a procedure for selecting the minimum-production-cost die from among a set of design alternatives. The mathematical content of the book is relatively simple and will present no difficulty to those who have taken basic c

  17. Influence of tungsten and titanium on the structure of chromium cast iron

    D. Kopyciński


    Full Text Available The paper analyses the as-cast state structure of chromium cast iron designed for operation under harsh impact-abrasive conditions. In the process of chromium iron castings manufacture, very strong influence on the structure of this material have the parameters of the technological process. Among others, adding to the Fe-Cr-C alloy the alloying elements like tungsten and titanium leads to the formation of additional carbides in the structure of this cast iron, which may favourably affect the casting properties, including the resistance to abrasive wear.

  18. Gods hand in die natuur

    A. Duvenage


    Full Text Available Kan ons van so iets spreek? Daaroor bestaan daar seker geen verskil nie. Die Bybel is vol daarvan van Genesis tot Openbaring. God is Skepper. ’n Ander vraag is of ons God ook kan ken uit wat daar in die natuur gebeur? Verloop alles nie maar volgens ewige natuurwette waaraan tog niks verander kan word nie? Ons bely egter dat die Here nie net in die hart van die mens gelê het wat ons noem die „saad van die religie” nie (semen religionis, maar dat ons Hom ook ken deur die skep- ping, onderhouding en regering van die hele wêreld, aangesien dit voor ons oë is soos ’n mooi boek waarin alle skepsels, groot en klein, die letters is wat ons die onsigbare dinge van God duidelik laat sien, nl. sy ewige krag en Goddelikheid ...; dinge wat almal genoegsaam is om die mense te oortuig en hulle alle verontskuldiging te ontneem (Art. 2 Ned. Gel. Bel..

  19. Die eunug in die klassieke mitologie en samelewing

    F. P. Retief


    Full Text Available Die konsep, eunug, wat na ’n gekastreerde persoon (gewoonlik manlik verwys, het sy oorsprong in die mitologie. Van hier word dit deurgevolg na die Klassieke tydperk. Kastrering vir religieuse redes was deel van godsdiensrituele gekoppel aan verering van aardgodinne en fertiliteit. Die kultusse wat aan die godinne Kubele, Hekate, Atargatis-Dea, Astarte, Artemis en Innana-Ishtar gewy was en wat deur eunugpriesters bedien was, word beskryf. Kastrering vir niereligieuse redes, oorwegend weens sosio-ekonomiese oorwegings, het waarskynlik tydens die 2de millennium v.C. sy oorsprong in Midde-Oosterse lande gehad vanwaar dit teen ongeveer die 5de eeu v.C. na Griekeland, en twee eeue later na Rome uitgebrei het. ’n Oorsig word gelewer van die invloed en rol van die eunug ten tye van die klassieke beskawing. Die sogenaamde “kongenitale eunug” waar hipogonadisme weens ’n aangebore letsel ontstaan, ’n baie seldsame verskynsel, word nie verder bespreek nie.


    D. Dimitrov


    Full Text Available

    ENGLISH ABSTRACT: This paper discusses the results obtained from studies on different Rapid Tooling process chains in order to improve the design and manufacture of foundry equipment that is used for sand casting of prototypes in final material. These prototypes are intended for functional and pre-production tests of vehicles. The Three Dimensional Printing process is used as core technology. Subsequently, while considering aspects such as time, cost, quality (accuracy and surface roughness, and tool life, a framework is presented for the evaluation and selection of the most suitable process chain in accordance with specific requirements. This research builds on an in-depth characterisation of the accuracy and repeatability of a 3D printing process.

    AFRIKAANSE OPSOMMING: Hierdie artikel bespreek die resultate wat verkry is tydens studies op verskillende Snel-Gereedskapvervaardigingproseskettings wat ondersoek is teneinde die ontwerp en vervaardiging van sandgietgereedskap, om prototipes in finale materiaal te vervaardig, te verbeter. Die prototipes is bestem vir gebruik in funksionele- en voorproduksietoetse van voertuie. Die sogenaamde Driedimensionele Drukproses (3DP is as kerntegnologie aangewend. Gevolglik, na oorweging van aspekte soos tyd, koste, kwaliteit (akkuraatheid en oppervlakafwerking, en gereedskapleeftyd, is ’n raamwerk ontwikkel vir die evaluering en seleksie van die mees geskikte prosesketting met inagname van spesifieke vereistes. Hierdie navorsing bou op ’n diepgaande karakterisering van die akkuraatheids- en herhaalbaarheidsvermoë van ’n 3D drukproses.