Study on Medium-Frequency Induction Hardening Process For automobile 42CrMo Concave Roller Surface

In modern steel industry, Concave work rolls are widely used in the rolling processing field, and their surface performance has a crucial impact on the operational efficiency and service life of rolling equipment. During the production process, our company found that the surface hardness consistency of 42CrMo concave work rolls after medium-frequency quenching was poor (low in the center and high on both sides), and there were spiral soft bands and uneven depth distribution of the quenched layer, which seriously affected the quality and performance of the rolled products. To address this issue, we studied the surface medium-frequency quenching process, analyzed the technical requirements for surface quenching of concave work rolls, and, based on their slender structural characteristics, redefined the quenching process flow. We optimized the quenching and furnace tempering temperatures, adopted continuous heating and spray quenching technology, added magnetic conductors to concentrate the heating power, adjusted the ascending speed of the inductor, and strictly controlled the distance between the inductor and the workpiece by using a self-made gauge. The test results of the workpieces after the improved medium-frequency quenching process showed that the surface hardness consistency of the concave work rolls was good, with a hardness of HRC42-48, a quenched layer depth of approximately 1.2mm, and a uniform fine martensitic structure, meeting the technical specifications. The above analysis indicates that the improved medium-frequency quenching process can effectively enhance product quality, reduce production costs, and shorten the production cycle, which is of great significance to actual production.