Numerical simulation of a magnetic induction coil for heat treatment of an AISI 4340 gear

In manufacturing industry, heat treatment is a fundamental requirement for improving the material quality of readily manufactured products. Induction heating technology is repeatable and easily controlled by the advantage of having an electronical control unit. Nowadays, numerical methods have gained so much importance that it become as a reference for the induction heating industry. Experimental methods are costly and time demanding procedures. However, making use of finite element method software, induction heating simulations of a steel gear can be performed relatively cost effective and in a short time. In this paper, induction heating simulation of an AISI 4340 steel gear using FEA software is performed. The effect of variation of inductor frequency and gear workpiece-inductor coil distance on the hardening depth of the gear surface is investigated. The temperature profile of the workpiece is obtained. From the temperature distribution on the steel gear workpiece, the regions of the gear at which the austenitizing temperature (Ac3) - responsible for martensite phase formation- are observed. From the numerical results, hardening profile and hardening depth of the gear is interpreted.