Residual stresses generated after induction hardening

In the same way as thermochemical treatments, surface induction heating followed by quenching generates a field of residual compressive stresses which, among other things, improves the fatigue life of the treated product.

Taking an interest in residual stresses during surface heating also means gaining a better understanding of tapping phenomena and the indications associated with the deformations caused by heat treatment.

Based on several scientific studies, the aim of this article is to understand the mechanisms involved in the generation of residual stresses during martensitic hardening following surface induction heating.

After a brief introduction to induction heating, which will describe the experimental protocol that led to the results you are about to see, the second section will be devoted to understanding the genesis of residual stresses in our case. It will review various concepts specific to residual stresses: mechanical hardenability and the thermo-kinetic approach associated with thermal gradients and transformation gradients at the origin of the generation of residual stresses in induction.

We will then discuss the impact of carbon percentage on X-ray diffraction results when estimating residual stresses using the Ψ ² method.