Analysis of Residual Stresses During Heat Treatment of Large Forged Shafts Considering Transformation Plasticity and Creep Deformation.

The long cooling time during heat treatment of a large forging due to mass effect leads to the creep deformation at not only high temperature but also transformation temperature ranges. Therefore, both the transformation plasticity and the creep together with the phase transformation significantly affect the stress distribution of the forging after the heat treatment. In this study, a FEM model considering both the transformation plasticity and creep was developed. Proposed model was integrated into commercial FEM codes ANSYS via user subroutines. The material properties of the transformation plasticity and creep were also measured experimentally. For experimental verification, the residual stress measurements of the large forged shaft are compared with those of the simulations. The simulations show that the residual stresses were mainly caused by the phase transformation stress. In particular, it is found that both the transformation plastic strain and the creep strain play important roles in simulating the residual stress during heat treatment of a large forged shaft. [ABSTRACT FROM AUTHOR]