Fatigue strength prediction of carburized 12Cr steel alloy: Effects of evaluation of maximum crack sizes and residual stress distribution

Abstract

Axial loading fatigue tests of carburized 12Cr steel alloy in long‐life regime were performed under stress ratios of −1 and 0. Fatigue fracture can be divided into surface failure, interior failure without fine granular area (FGA), and interior failure with FGA. By considering the effects of the tensile limit, the evaluation of maximum crack sizes (inclusion sizes and FGA sizes), and residual stress distribution, the fatigue strength prediction model of carburized 12Cr steel alloy for inclusion‐FGA‐fisheye induced failure in low stress level region can be established. By comparing the predicted results evaluated by generalized extreme values (GEV) with generalized Pareto (GP), the GP distribution is more suitable to predict the fatigue limit of the carburized 12Cr steel alloy. Furthermore, by using the relationship between inclusion sizes and FGA sizes, the fatigue limit prediction model for the design of components can be established, and the result is extremely accurate for the carburized 12Cr steel alloy.

Prediction of Residual Stress of Carburized Steel Based on Machine Learning

“…According to Northwood et al [22], the amount of retained austenite and the residual stress increase as the carbon content increases, and they decrease after tempering. Deng et al [23] found that as the carburizing temperature and carbon potential increase, the amount of carbon in the carburized layer increases, which in turn leads to an increase in residual stress and inhibits the initiation of cracks. Yang et al [24] studied the calculation model for retained austenite, martensite, and residual stress by using the finite element method under different carburizing processes.…”