Simulation Of Microstructure Evolution Of 38MnVS6 Non-Quenched Steel During Forging Process Based On Redevelopment Of DEFORM

With the development of automotive industry and non-quenched steel, the application and consumption of non-quenched steel increases gradually. Besides using new material, in order to achieve the parts with high quality it is necessary to control the forging technology. As an important process during the automobile parts product, the forging influenced the quality of parts directly. During the hot forging process, temperature, strain rate and parameters of dies have effect on the microstructure of forging which determine the quality of parts. In this paper, the 38MnVS6 non-quenched steel was investigated. Based on the microstructure models we built, the user defined microstructure subroutine was compiled using redevelopment of DEFORM.In this paper, the research and application of non-quenched steel, especially 38MnVS6, was introduced firstly. Based on the hot compress simulation tests, the microstructure models such as dynamic recrystallization models, meta-dynamic recrystallization models, static recrystallization models and grain growth models were founded. Then the microstructure evolution subroutine of forging process (including heating process, pre-forge, interval, finish forge and cooling process) was compiled using redevelopment of DEFORM. The grain growth process, one-pass hot compress process and two-pass hot compress process were simulated to check the microstructure evolution subroutine. By comparing simulated results with the test results, the user subroutine was verified.The forging process of jaw crusher eccentric shaft, which shape is simple, was simulated using the user defined subroutine firstly. The distribution of temperature, effective strain, and microstructure evolution in workpiece during the forging process were analyzed. And the average grain size-time curves of unique points were gotten. Then the forging process of crankshaft, a complex forging, with the parameters which could fulfill the crankshaft was simulated as well. The distributions of temperature and effective strain at different forge stages were analyzed. And then the microstructure evolution of different stages, for example grain growth at heating process, dynamic recrystallization at pre-forge and finish forge, grain growth, meta-dynamic recrystallization, static recrystallization at interval and cooling process, were discussed. At last the distributions of average grain size at different stages were achieved,· which could provide a theoretical base and guide for the actual product.