Establishment of a Numerical Model and Process Optimization for the Moving Induction Hardening of a Whole-Roll Flatness Roll

The surface of a whole-roll flatness roll is in long-term contact with the steel strip, leading to slipping and wear and placing higher demands on the performance of the roll surface. This study establishes a finite element model for moving induction quenching and a phase transformation hardness numerical model by generating multi-field simulations and hardness predictions for the flatness roll during induction quenching. First, the thermal–physical properties of the roll material, MC3, are calculated using JMatPro V13.0. The dynamic domain and moving mesh techniques are applied in COMSOL Multiphysics to simulate time-varying boundary conditions, and the JMAK and K-M phase transformation models are used for electromagnetic–thermal–microstructure field simulations. Subsequently, the Taguchi method is used to optimize the induction quenching process of the flatness roll. After optimization, the martensitic hardened layer depth along the axial direction of the roll becomes uniformly distributed near the target value of 3 mm. Finally, through the modified Maynier hardness model, the corrected formula for the Vickers hardness of MC3 is obtained. The calculated hardness value of the roll surface in the simulation model reaches 950 HV, which agrees well with the experimental hardness results, validating the ability of the numerical model to guide specific processes.