New Approach to Optimization of Surface Induction Hardening Process

The article presents a new approach to solving complex optimization problems for surface induction hardening of steel workpieces. The first optimization stage for hardening complex-shaped parts consists of the optimization of inductor coils design aimed at implementing the fast uniform heating of the considered hardened layer above the Curie point without local overheating and exceeding the limits of thermal stress. In the second stage the optimal control problem is formulated and solved considering technological constraints on the main controlled process parameters. In the case of a priori parameterization of control actions, the optimized controlling parameters can be included in the vector of design parameters, and then the combined optimization problem can be formulated and solved. The numerical procedure of optimization problems solving is based on the alternance method of optimal control theory for distributed parameter systems. The numerical multi-dimensional FEM model of the induction surface hardening process is developed in ANSYS software and integrated into the optimization procedure. The paper presents the test case of the suggested approach application to induction surface hardening of steel L-shaped billet.