A modified temperature-phase transformation-stress coupled 3D non-linear mathematical model and a series of subroutines on the non-liner MARC (MARC Analysis Research Corporation) are developed. Then this modified model has been utilized to simulate the heat treatment processes of 280 connecting rod of 16 V280ZJ diesel locomotive. The simulation results are basically in agreement with the experiments, which testify that the mathematical model and method are feasible. In addition, the simulation can not only obtain the transient temperature and micro structure of heat treatment process, but also provide a sound scientific basis for the heat treatment workers.
J.S. Ye, Z.R. Ye, A. Yang,and Y.LuaSchool of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai 200030, China Ziyang Internal-Combustion Factory of Sichuan, Ziyang 641000, China
A temperature phase transformation stress coupled 3D nonlinear mathematical model has been proposed for forecasting distortion of workpieces on the cooling processes in this paper. Moreover, a series of subroutines were developed on the MARC (analysis research corporation) software platform and the simulation result is basically identical with the experimental one that measured on the workpiece shape with LEITZ equipment. This verifies that the mathematical model and method are feasible.
Many disadvantages exist in the traditional die design method which belongs to serial pattern. It is well known that heat treatment is highly important to the dies. A new idea of concurrent design for heat treatment process of die and mould was developed in order to overcome the existent shortcomings of heat treatment process. Heat treatment CAD/CAE was integrated with concurrent circumstance and the relevant model was built. These investigations can remarkably improve efficiency, reduce cost and ensure quality of R and D for products.
LI XiongZHANG Hong bingRUAN Xue-yuLUO Zhong-huaZHANG Yan
280 connecting rod is one of the most important parts for 16V280ZJ diesel locomotive, so it needs much better mechanical performance. However, the crack is often generated at the middle section of connecting rod body on heat treatment process. A temperature-phase transformation-stress coupled 3D non-linear mathematical model has been developed to analyze the reasons of cracking. The simulation and experimental results show that the compressive stress on the cracking position is close to the fracture stress of connecting rod and the reasons of crack are mainly contributed to the carbon content excess of original material or the aging of quenchant.
The 1Cr18Ni9Ti specimens were treated respectively with pulse current under 520 V and 2 600 V during solidification and the solidification structure was observed. The results showed that pulse current can refine solidification grains, cut primary dentrities remarkably and reduce second dentritic arm spacing. The mechanism and effect are changed with operation parameters.