A modified temperature-phase transformation-stress coupled 3D non-linear mathemat-ical model and a series of subroutines on the non-liner MARC (MARC Analysis Re-search Corporation) are developed. Then this modified model has been utilized to simu-late the heat treatment processes of 280 connecting rod of 16V280ZJ diesel locomotive.The simulation results are basically in agreement with the experiments, which testifythat the mathematical model and method are feasible. In addition, the simulationcan not only obtain the transient temperature and microstructure of heat treatmentprocess, 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.
A novel model of the evolution of microstructure during continuous cooling with the formation of proeutectoid ferrite in steel was proposed from a Voronoi construction for the austenite grains, based on the Rappaz′s integral nucleation model and the assumption that the ferrite nucleates at the edges of the original austenite grains and the successive growth of the ferrite grain is radial. The model can be used to calculate the fraction of ferrite as a function of time or temperature during continuous cooling, and to determine the microstructure of ferrite. The calculated results are in agreement with experimental results investigated in 0.38C-0.28Si-0.55Mn-0.92Cr-0.20Mo steel under continuous cooling using a Gleeble 1500 thermomechanical simulator.
