On the Analysis of Distortion and Residual Stress in Carburized Steels

This paper appraises the accuracy with which distortion and residual stress can be predicted in carburized and quenched gear steels. An experimental sample is heattreated such that a nonsymmetric carbon profile results. During quenching, the strip develops longitudinal transformation strains that result in amplified transverse deflections, similar to those of thin bimetallic strips. Deformations in carburized SAE 4023 and SAE 4620 alloys are compared with finite element predictions. The finite element procedure is based on an elastic-plastic yield surface which includes dependence on temperature. The analysis uses property data published and used by others. Some, but not all, of the predicted distortions agree with experiments; the study shows that distortions are quite sensitive to small variations in constitutive parameters. The paper includes recommendations for practitioners using finite element procedures for prediction of residual stress.