Simulation of Phase Transformation in Welding Heat Affected Zone of 9% percent Ni steel

Based on experimental SHCCT diagram of 9% Ni steel, parameters of Leblond model and Koistinen-Marburger model for phase transformation were presented. With SYSWELD software, the presented parameters were verified and confirmed to be effective for simulation of phase transformation in HAZ of 9% Ni steel. Using the verified phase transformation models, simulation of phase transformation in HAZ under different welding conditions was performed and calculation results proved to correspond to reality. Results showed that martensite developed in coarse-grained HAZ after welding. Phase transformation was influenced by welding parameters and took a certain period of time to complete.