| Martensitic transformation exists in various materials. It is widely used in many fields such as steel strengthening, material toughening and shape memory effect. The more people pursuing better material property, the deeper research for the martensitic transformation becomes, and numerical simulation is one of the important methods of the research.The temperature-changed martensitic transformation is occurred during quenching treatment. It is a dynamic process of the highly coupling calculation of temperature field, stress field and microstructure distribution calculations. In this paper, the mechanical properties of material is assumed to be the practical anisotropy microstructure (random distributions of grains), and the 0-1 phase transformed model of stress affecting transformation is put forward. Considering the transformation latent heat, we establish the coupling calculation of temperature field, stress field and microstructure distribution calculations, and the microstructure simulation process is conducted for the temperature-changed martensitic transformation by taking quenching treatment of a 45# thin,long,steel bar for example.The calculation results show that the whole model temperature of considering the transformation latent heat is higher than without regard to it, and with the time increased, the difference between them becomes larger in the first place. Secondly, the random distributions of crystal grains play an important role in thermal stress, so it is significant to take it into account during transformation process. Thirdly, with the time going on, the temperature-changed martensitic transformation simulated in consideration of the anisotropy of the microstructure push on basically from outer layers to interior ones, but the transformation process of grains can be different though the temperature field is same, furthermore, residual austenite is distributed randomly.
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