Koichi Anzai

Development of Cup-Cast Method; Semi-Solid Slurry Preparation without External Stirring Force

Semi-Solid metal (SSM) processing is now considered a commercially successful manufacturing route producing millions of near net shape parts per annum for the automotive industry. Although semi-solid process is currently widely used as a manufacturing process which produces near net-shape metal component, the processes those used for the preparation of semi-solid slurry still take a great deal of time, energy and money. Cup cast method – recently developed by the authors – is able to make semi-solid slurry preparation as easy as pouring water from a pitcher into drinking glass. In this method globular solid particles are prepared by controlling the turbulence and heat distribution in the melt through pouring instead of applying certain external stirring forces, in other common method. In the current study, cup cast method applied to Al-A356 alloy using simple cylinder. Vital factors of this method were optimized by investigating micro-structures.

The Effect of Solidification Models on the Prediction Results of the Temperature Change of the Aluminum Cylinder Head Estimated by FDM Solidification Analysis

This paper presents the prediction results of the temperature change during the solidification process of the cylinder head made of the AC2A aluminum alloy. Prediction results have been obtained by using the FDM solidification analysis based on two different solidification models were investigated. Here, the solidification model means functional relationship between the Temperature and the Fraction Solid. The first model is a simple Linear function and the second model is estimated from DSC measurement. The comparison between the simulated and measured temperatures of the aluminum cylinder head revealed that the selection of solidification models significantly reflects the prediction results. The DSC model gives higher prediction accuracy of the temperature change than the Linear model. The solidification models estimated by using Thermo- Calc and UMSA [3] were also investigated.

Quick Semi-Solid Slurry Making Method Using Metallic Cup

The needs for high-strength and light weight structural materials have increased in automotive and aerospace structure applications. The semi-solid processed light alloys inherently offer the opportunity to produce high integrity components for these requirements. Various processing methods exist for applying agitation to a molten metal during solidification to obtain metal slurries suitable for semi-solid metal processing. In this paper, a new technique (Cup-Cast method) to achieve semi-solid metal structure using agitation and direct spherical growth during solidification is reported. Cup-Cast method is the most quick and simple semi-solid processing route which semi-solid slurry would be prepared just by pouring molten metal into a metallic cup. In this study Cup-Cast method was introduced and effect of process parameters on micro-structural characterization of slurry prepared by this method was investigated.

Semi-Solid Slurry Preparation without Additional Stirring, Cup-Cast Method

The needs for high-strength and lightweight structural materials have increased in automotive and aerospace structural applications. Semi-solid processed light alloys have satisfied these requirements because of processing advantages and significant weight reduction. Conventional semi-solid casting methods have got a wide variety of problems and difficulties. The cup-cast method that has been just developed is a novel process that make semi-solid casting as easy as pouring the water from a pitcher into a drinking glass, and avoid all the problem and difficulties of other semi-solid casting processes. Cup cast method is based on the heat and mass transfer and spherical equiaxed particles with controlling the nucleation and growth of solid particles were produced. In this study the different factor of this method was optimized by micro-structural investigation on the Al-A356 alloy. Pouring height and temperature, duration of pouring, and cup coating had played important roles in this method.

An Experimental Simulation of Oscillation Marks and Uneven Solidification Using Sn-Bi Alloys

AbstractAn experimental simulation of oscillation marks and uneven solidification of solid shells was conducted by dipping a chill plate into melts of Sn-Bi alloys. Surface wrinkles resulted from d...

Effect of Zr Addition on Magnetostriction of Tb-Dy-Fe Alloys Prepared by Micro-Pulling-Down Method

Effects of Zr addition and annealing on the magnetostriction of Tb-Dy-Fe alloy crystals were investigated. The (Fe1.9Tb0.27Dy0.73)1-xZrx (x: 0, 0.0125, 0.025, 0.05, 0.075) crystal fibers about 2 mm in diameter were grown by the micro-pulling-down (μ-PD) method. The grown crystals showed the low chemical segregation along longitudinal direction and the growth direction was oriented in the <311> direction. The saturation magnetostriction of the fiber increases with increasing the Zr content, annealing temperature and annealing time. The fiber-shape Tb-Dy-Fe crystals prepared by the μ-PD method are promising for the applications as sensors and actuators.

Analytical Model for Heat Transfer Phenomena in Cup-Cast Method

Cup-cast method is a new method deals with semi-solid slurry preparation recently developed by the authors. In this method, suspension of globular solid particles in molten metal is prepared by controlling the nucleation and growth of solid-particles through the simplest and quickest techniques. In this method, heat transfer phenomenon plays an important role in governing the shape, size, and fraction of solid particles. In the current study, a heat transfer model was proposed and applied to Al-A356 alloy semi-solid slurry preparation. The heat transfer model was based on heat balance consideration between cup and slurry and it was in a good agreement with experimental results.

Simulation tools for practical die casting processes

A casting CAE system named ADSTEFAN has been developed through an industry-university cooperative project in Japan. It is specifically designed for casting engineers to realize ease of use. A couple of days are enough to learn how to use it even if the casting engineer may have little knowledge and experience with numerical simulation. Only a few operations are necessary to prepare input data for solidification and mold filling simulation. Quick calculation with less memory is one of the main features of ADSTEFAN. A huge scale simulation, such as over 100,000,000 meshes, can be solved on an engineering workstation or PC. The various modules to estimate cyclic steady state, size and shape of shrinkage defects and flow pattern in shot sleeve are incorporated into the system in addition to fundamental solidification and filling simulation. Some typical results of application to die casting process are also described.

Solidification Analysis for Die Casting by Cyclic Steady Heat Balance Method

Solidfcation Analysis for Die Casting by Cyclic Steady Heat Balance Method Kazuhiro Oda , Koich Anzai , Eisuke Niyama and Hirosh Kubo The d i e c a s t i n g p r o c e s i n v o J v e s t h e r e p a t d c喜s t i n g and s p r a y c o l i n g ( o r a i r c o l i n g ) i n 詮 d i e c喜v i t y . T h を t r a c e o f t e m p r a u v a r i 韮t i o n o f 喜 d i e u s a l y shows up w i t h a c y d i s t e a d y s t a t e 書長官昌b o u t 10 cydes. T h i s paer d e s c r i b e s a new t h e r m a l 皐n a l y s i 吾郎ethod ( C y d i c S t e a d y he 喜t ba 泌氏ε関e t h o d ‘C括的, whic c a n p r e d i c t t h e d i e tempr 語t u r e 波書 c y d i s t e a d y 抗告t e w i t h o u t 託児p e a t d n u m e r i c a l c昌1cむ l a t i o n . I n CSM , t h r e k i n d 話 o f m をan c a v i t y s u r f a c e t e m p r a t u e s , i ‘e . d u r i n g c a s t i n g , s p r a y c o l i n g and one c y l e , a r e t a k e n i n t o c o n s i d e r a t i o n , S i n c e r e l a t i o n s betwn t h e 総 mperatu and c o l i n g p a r m e t s ( c a s t t i m e , s p r a y t i m e . c o l i n g s t r e n g t h . e t c ) a r e exprsd a n a l y t i c a l y . t h e e f e c t o f c o l i n g c o n d i t o n s on t h e d i e t e m p r a t u e c a n be e a s i l y s u r v e y d . Mean t e m p r a u d i s t r i b u t i o n w i t h i n a d i e c a n be a l s o c a l c u l a t e d by CSM. Asuming i t a s a i n i t i l c o n d i t o n o f t h e d i e , s o l i d i f i c a t i o n a n l y s i i n a c y c l i c s t e a d y s t a t e c a n e f i c i e n t J y be d o n e .

Efficient Explicit-Implicit Finite Difference Algorithm for Transient Heat Conduction Problems

An efficient explicit-implicit finite difference algorithm for the transient heat conduction problem is developed. The algorithm is based on the alternative use of the explicit and implicit scheme for the time integral of the transient heat conduction equation depending on the total heat conductance of mesh elements. The algorithm has so simple a structure that it can be applicable to a variety of transient heat conduction problems. Particularly, the algorithm is effective for multi domain problems and strongly irregular mesh problems. In this paper, the basic idea of the algorithm and a method to determine an optimum time increment are described. Also, the evaluated results of accuracy and acceleration of the calculation by the application to the one-dimensional transient heat conduction problems are described.