FEM Simulation of Quenching Process and Investigation of Residual Stresses of Crankshafts

Abstract

Compressive residual stresses and high hardness introduced by induction quenching are often used to improve the mechanical performance of crankshafts in engines. In this paper, in order to predict the fatigue strength of the crankshafts in a diesel engine accurately, the quenching process and the stress fields of the crankshaft are simulated by finite element method (FEM) and then the residual stresses are obtained. Quenching is a high non-linear process because of the coupling of the temperature, phase transformation and stress/strain fields. The transient temperature field is firstly solved using a quasi-coupling method to simulate the relationship of the temperature and the phase transformation. Based on the results of the temperature and phase transformation fields, the thermo-elastic-plastic analysis is then carried out to calculate the stress fields including the thermal stresses and the phase transformation stresses. At last the residual stress distribution at the room temperature is obtained.