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The distortions of C-ring and cut cylinder of austenitic stainless steel after water quenching were investigated using simulation and experiment methods. The results indicated that the accurate measurement of temperature had a major influence on interfacial heat transfer coefficient (IHTC) which is calculated using the inverse analysis method. The sparse data of the high temperature stage due to low sampling frequency resulted in the lower value of IHTC. The simulated distortion during water quenching was mostly decided by the change of IHTC. The simulation results showed that the trend and magnitude of distortion predicted by the IHTCH (calculated from the data of high sampling frequency) agreed better with the experiments than that by the IHTCL (calculated from the data of low sampling frequency). The further analysis showed that the IHTC at high temperature had the great influence on the calculated yield behavior of materials. The high values of IHTC caused that the work piece kept in the yield status at higher temperature and wider temperature range. So the simulation using the IHTCH predicted more serious plastic deformation and larger rigid movement. Further analysis showed that the simulation result of distortions was sensitive to the variation of IHTC at the high temperature stage, while insensitive to the variation at the low temperature stage.

Based on the two-parameter phase field model of polycrystalline, the grain growth in polycrystalline material during isothermal holding is simulated by using the adaptive finite element method. The calculated results demonstrates that the cusp grain boundaries are inclined to planar and some small grains coarsen into larger ones through grain boundary migration due to the curvature effect. When the grain boundary misorientations are small enough and meet certain energy and geometric conditions, two grains can rotate to reduce external energy of grain boundaries and coarsen into a single grain. All the modelling results are in good agreement with some experimental observations, and the phase-field model can be successfully employed to simulate polycrystalline grain growth.

The deformation induced dynamic transformation （DIDT） of a Fe-C alloy above austenite transformation equilibrium temperature is simulated by using a Q-state potts Monte Carlo （MC） model. The austenite-to-ferrite transformation, dynamic recrystallization （DRX） of austenite and ferrite, and the ferrite-to-austenite reverse transformation can be simulated simultaneously in the same MC model by building suitable MC transition rules. Meanwhile, an affine transformation model based on vector operation is also coupled with the MC model for the first time for tracking the changes in grain shape during dynamic transformation. The formation of ferrite during DIDT and the influence of austenite DRX on DIDT are simulated based on this MC model. The simulation results show that the competition between the DRX of austenite and the austenite-to-ferrite transformation causes the oscillation behaviour of ferrite kinetics.