A Study of Induction Hardening Parameters for the DIN 42CrMo(4) Alloy through Its Microhardness, Corrosion Resistance, and Microstructure Examination

The research work focused on microstructural changes that occurred in DIN 42CrMo(4) alloy during the induction hardening process with the emphasis on its corrosion and microhardness variations. In this strategy, experiments were performed on the gradually increasing values of induction heating power and time to observe the response of the studied alloy. The optical and scanning electron microscopy was used to examine the microstructures of the processed alloy. Mechanical performance of the induction hardened alloy was characterized using microhardness examination. It was found that the percentage of martensite phase fraction increased with induction heating powers i.e., of 10, 14, 18, and 22 kW. Similar trend was observed for extended induction heating time from 3 to 9 s. A characteristic transformation in martensitic morphology was also observed due to change in processing parameters, which created a significant effect on the corrosion performance and hardness value of the studied alloy. Hardness of the alloy progressively increases with the rise of induction heating power and time and stabilizes at higher input values of induction parameters due to complete execution of martensitic structure. On the characterization of the electrochemical properties, the study revealed that martensitic morphology played dramatic role in the corrosion performance of the alloy. it was found that lath martensitic structure offered greater corrosion resistance compared to coarse martensite with a trivial change in hardness value. Thus, utilization of proper induction parameters needs to be applied for the properties to be optimum.