Model of stress-induced phase transformation and prediction of internal stresses of large steel workpieces during quenching

Abstract

Because internal stresses in large steel workpieces are high during quenching, the coupling of stresses and phase transformations should be considered to predict the internal stresses. The influence of stresses on phase transformations was investigated by dilatometer experiments applied uniaxial loads, modified John-Mehl-Avrami equation and Koistinen-Marburger equation were suggested to model the stress-phase transformation coupling during quenching. The model suggested was used in an in-house FEM code NSHT developed by authors. The distribution of residual stresses of a hollow cylinder specimen was calculated to investigate the stress-induced phase transformation. The internal stresses of a generator rotor during different quenching processes and stresses at the groove bottom of a turbine rotor in quenching were analyzed.