Influence of various induction-heating and grinding conditions on residual stress profiles

Abstract

In induction surface hardening, a maximum compressive residual stress in the surface layer is achieved. The transition from compressive to tensile residual stresses should be as gentle as possible, lessening the effect of stress concentration on loaded components. This contributes to the fact that a machined component is less susceptible to overloads in operation. It has been shown that residual stresses are closely linked to hardness variations and microstructure in the transition zone of the hardened layer and base material, i.e., in the narrow range between the hardened and non-hardened microstructure. Additional grinding of induction hardened surface causes the stress state in the surface layer to deteriorate, since grinding always induces tensile stresses. Through the right selection of machining conditions and grinding wheels, taking into account its properties, the engineer will contribute to lessening tensile residual stresses and will avoid causing the favourable residual stress state to deteriorate after induction surface hardening.