Stress State of 12% Ni Maraging Steel After a Modified Procedure of Precipitation Hardening

Abstract

Fatigue resistance of a surface layer of dynamically and thermomechanically loaded machine components and tool parts can be improved with a combination of mechanical hardening by cold deformation and thermal precipitation hardening. One of the mechanical processes of surface hardening is a relatively simple and accessible process of roto peening. The hardening effect of roto peening is related to a local plastic deformation of the surface layer, which results in a higher hardness and an increase of compressive residual stresses. The application of roto peening or related process is possible and efficient with maraging steels used in the production of mechanically loaded tools and machine components. It turned out that in such combined hardening processes applied to maraging steels certain limitations related to the temperature of precipitation annealing should be considered. In the opposite case, thermal hardening can annul all the advantages obtained in the previous mechanical hardening of the surface layer.