Mathematical simulation of plasma nitriding of stainless steel in view of the effect of residual stresses

Abstract

The paper studies the effect of frictional pretreatment on the change in the properties of the surface layer of austenitic stainless steel subsequently subjected to low-temperature ionic nitriding in electron beam plasma. Under friction-force loading, near the specimen surface there appear residual compressive stresses changing the stress state in the gradient surface layer. Two mathematical models of the process of ion nitriding have been constructed, which take into consideration the effect of residual stresses with a constant diffusion coefficient. Besides, one of the models considers the effect of internal compressive stresses arising in the surface layer during the process of nitriding. Algorithms based on the boundary element method (BEM) are proposed for solving boundary value problems. Model examples illustrating the work of the algorithms have been solved.