Simulation of induction hardening: Simulative sensitivity analysis with respect to material parameters and the surface layer state

Abstract

Inductive surface hardening is a widely used steel heat treatment process improving wear and contact resistance and inducing compressive residual stresses close to the surface. To achieve the optimal state the interaction of many process parameters and their influence on the final part properties have to be worked out. This can be accomplished by experimental or simulative investigations. Here a simulative consideration of the process allows an investigation of a big parameter field and has the advantage of predictions compared to experiments. One disadvantage of a simulative consideration is that all relevant material properties of the regarded steel have to be determined with huge experimental effort. This work will provide models and estimations to calculate the necessary phase dependent material properties for a wide range of low-alloyed steels. The acquisition is based on a literature study. Furthermore the influence of each material parameter on the surface state after a typical induction hardening process, regarding residual stresses and the hardening depth, is analysed. The sensitivity analysis is performed using a multiphysical finite element (FE) model of a ring shaped sample out of AISI4140, including over 120 simulations. With the presented results an improved understanding of the interactions during the induction hardening process is achieved and important material parameters, which have a significant influence on the resulting surface layer state, are elaborated.