Influence of induction surface heating and quenching on residual stress profiles, followed by grinding

In the case of induction surface hardening, a maximum compressive residual stress in the surface layer is achieved. The transition from compressive into tensile residual stresses should be as gentle as possible, lessening the effect of stress concentration in the 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 variation 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 the hardened induction surface deteriorates the stress state in the surface layer, since grinding has always induced tensile stresses. With the correct selection of machining conditions and grinding wheel, the engineer will be able to lessen the tensile residual stresses and will avoid deteriorating the favourable residual stress state after induction surface hardening.