Evolution of magnetic properties during tempering

Abstract

Quality control in heat treatment of steel is often conducted after the treatment. Failure to confine within the specified range of mechanical properties may lead to wasted energy and production resources. Performing quality control in-line in the heat treatment process allows for early detection and possibility to react to changes in the process. The prospects of utilizing the change in the electromagnetic (EM) properties of steel, as means for quality control, are investigated in this paper. The focus is on the tempering process of hardened SS2244 (42CrMoS4) steel. The tempering takes the hardness of the steel from approximately 600 HV down to around 400 HV. The EM signature of the steel is recorded during the tempering process. This is later compared with results from more traditional means of material characterization, such as laser scanning microscopy, X-ray diffractometry and Vickers microhardness measurement. This initial study shows clear indications of precise detection of the hardness through EM properties during the tempering process of selected material.

Micromagnetic and Microstructural Characterization of Ferromagnetic Steels in Different Heat Treatment Conditions

“…Section 3.2). However, it should be noted in this context that for further investigations, the magnetic hystereses should not only be quantified by H C , B R , and B max , among others, but also the area enclosed by the hysteresis, i.e., the magnetic hysteresis loss, should be used as a measure of the energy required to complete a full magnetization cycle [15]. Another possible approach to investigate the micromagnetic behavior would be to compare the occurring maximum slope of the magnetic hysteresis at the magnetic flux B = 0 T. As mentioned above, consistent changes in the hysteresis slope were observed here for the material states investigated.…”

“…The influence of selected microstructural properties on individual micromagnetic parameters has been described in several publications [15][16][17]. The resulting conclusions focus on a specific material or material state.…”