Influence of the Parameters of Induction Heat Treatment on the Mechanical Properties of 50CrMo4*

Abstract

Abstract Induction heat treatment facilities have a wide application range for heat treatment of cylindrically shaped materials in the steel processing industry due to their reduced process-time and high throughput. The adjustment of the heat treatment process usually aims at reaching a desired hardness. However, the question arises whether the full potential of the applied material is actually exploited. Therefore, this work systematically investigates the influence of the primary microstructure, austenitisation and tempering conditions to the resulting notch impact energy and flow behaviour of a 50CrMo4 quenched and tempered steel, with normalised and soft-annealed prior microstructures. The heat treatments, performed with a laboratory induction heat treatment facility, show that low austenitising temperatures lead to a distinct yield point with reduced strain hardening, while increasing the tempering heating rate results in the precipitation of smaller carbides and a significant increase in tensile strength. Austenitising needs to be adjusted to the primary microstructure to reach an optimum solution state to exploit the hardness and notch impact energy potential.