Prediction of internal stresses in large-size work pieces during intensive quenching based on temperature microstructure stress coupled model

Stress-induced transformation and transformation plasticity of 26Cr2Ni4MoV (0.25%C–1.75%Cr–3.3%Ni-0.4%Mo–0.14%V) and 30Cr1Mo1V (0.30%C–1.2%Cr–1.15%Mo–0.24%V) steel were investigated via dilatometric tests under applied external loads. The influence of stresses on diffusive transformations is described by a modified John-Mehl-Avrami formula, stress-induced non-diffusion transformation is governed by a modified Koinstinen-Marburger formula. A temperature-microstructure-stress coupled model was developed under the framework of thermo-elastic-plastic theory. The distributions of residual stress in hollow cylinders after quenching were measured to validate the model. The internal stresses during quenching of a turbine rotor with grooves and a generator rotor were analysed with an in-house FEM code.