How to Select Induction Surface Hardening and Finished Grinding Conditions in Order to Ensure High Compressive Residual Stresses on Machine Parts Surface

Abstract

Induction surface hardening creates very desirable residual stresses in hardened surface layer. Residual stresses are always of compressive nature and are usually present to the depth of the induction - hardened layer. In general, efforts should be made that after induction hardening we get low or moderate residual stresses in the transition area. Manufacturing engineers are often confronted with the question of how to achieve this kind of residual stress profile. It should be emphasized here that because of their lower heat conductivity alloyed steels for surface hardening are very difficult to treat and it is difficult to ensure desirable residual stresses in the transition area. That is why special alloyed steels are available that in this respect display a more favourable behaviour in heating and quenching. It is due to these difficulties that delamination of the surface to the very core may occur. By right selection of grinding wheel and grinding conditions taking into accounts physical and mechanical properties of the workpiece material will be kept back very favourabe compressive residual stresses in the hardened surface layer.