LIU Qiyang LI Qingchun ZHANG Jiren Harbin Institute of Technology
,
Harbin
,
China LIU Qiyang
,
Division of Foundry
,
Department of Mechanical Engineering No.2
,
South China University of Technology
,
Guangzhou
,
China
金属学报(英文版)
By inserting the single crystal silicon seeds into Sr modified Al-22wt-% Si alloy melts,the fact that nucleation and growth of Si-phase are affected by Sr addition has been confirmed.It is suggested that this effect is caused by the adsorption of Sr on{111}_(si),and the modification of eutectic structure results from the variation of leading phase in the eutectic from Si to α-Al.
关键词:
Al-Si alloy
,
null
,
null
L.L. Chen
,
R.X. Liu and H.T. Lin College of Materials Science and Engineering
,
Huazhong University of Science and Technology
,
Wuhan 430074
,
China
金属学报(英文版)
In this paper, the development status of casting numerical simulation technology is introduced. In additional, mathematical model, solution method, initial condition, boundary condition and defect predicting scheme of foundry process are also analyzed, which include the mold filling process, solidification process and the process coupling fluid flow with heat transfer. Finally, a practical casting is taken out to show how to predict defects and optimize foundry process with numerical simulation technology.
关键词:
foundry
,
null
,
null
,
null
,
null
ZHAI Qijie
,
HU Hanqi
,
University of Science and Technology Beijing
,
Beijing
,
China HU Hanqi
,
Professor
,
Faculty of Foundry
,
University of Science and Technology Beijing
,
Beijing 100083
,
China
金属学报(英文版)
The expressions of the dependence of nitrogen solubility in molten gray cast iron on the temperature and composition of the melt were proposed under the condition of foundry practice. Three gray cast iron specimens with different compositions were examined in good agreement with the derived expression.
关键词:
gray cast iron
,
null
,
null
Yanxiang LI
,
Xiao HU
,
Xuerong XU
材料科学技术（英）
The development of thermal analysis techniques for evaluation of cast alloy melt quality and its current applications in the foundry were reviewed. The characteristics of the current thermal analysis techniques were analyzed. A new comprehensive method for cooling curve recognition has been proposed. The evaluation of cast alloy melt quality was realized.
关键词:
Y.Z. Zhao*
,
Q. Gao
,
Y.C. Liu
金属学报(英文版)
The microstructures of the Zn-27Al alloy after modification, solid-solution treatment, and natural aging were studied. It was clarified why the damping properties of Zn-27Al alloys, after treatment, had advanced most on the basis of analyzing the microstructures. Approximate expressions have been educed, which can be used to quantificationally work out the damping of the Zn-27Al alloy on the basis of the micro interface sliding model. By comparing the testing damping properties of the foundry Zn-27Al alloys and the Zn-27Al alloys after modification, solid solution, and natural aging, it was shown that the expressions were rational.
关键词:
modification
,
固溶时效
,
阻尼机理
,
微观界面滑动模型
Baicheng LIU
,
Wei QIU
,
Houfa SHEN
,
Zhiqiang GAO (Dept. of Mechanical Engineering
,
Tsinghua University Beijing 100084
,
China)
材料科学技术（英）
In this paper, an algorithm for simulating fluid flow and heat transfer for mold filling of shaped castings is presented. The main features of the algorithm include: 1) a simple but practical technique based on VOF method to determine free surface, 2) an explicit scheme of enthalpy to solve the energy equation more efficiently, and 3) an effective treatment to modify the flux deviation due to pressure iteration. In order to verify these methods, well controlled experiments have been repeatedly done with both water analog and gray iron pouring experiments to record the flow patterns and temperature variations. The calculated results are in accordance with the experimental ones. For the applications, the simulated initial temperature distribution right after mold filling was used to analyse subsequent solidification and to predict shrinkage defects.Actual castings were poured and tested in a foundry plant. The reuslts show that the defects predication with considering fluid flow effects is more precise than that without considering the effects.
关键词:
