Residual stresses analysis during quenching of 36NiCrMo16 steel

This study concerns residual stress generated by bulk heat treatment of 36NiCrMo16 steel french grade. The aim of this study is to develop a model for prediction of the residual stresses state generated by quenching. The resolution of this problem requires the development of two numeric simulation models, using a standard FEM code. The first is a non-linear transient model allowing simulating of space-time distribution of temperature from the austenitic temperature to the cooling temperature. The latter is a non-linear transientmodel allowing themechanical behaviour simulation of the specimen introducing his thermal history during cooling as loading. We propose the definition of a global expansion coefficient to take into account the simultaneous and cumulated thermal and martensitic transformation strains. Mechanical features and thermophysics properties are described in space-time evolutions depending on the temperature and the present phases. Simulated residual stresses evolution are compared with stresses measured by hole-drilling method and by X-ray diffraction.