Numerical Simulation And Optimization Of Induction Hardening Process Of Plate Roll

Plate shape is the key quality index of cold rolled strip,and plate shape roll is the core equipment of plate shape inspection system.The plate roller detects the plate shape by directly detecting the tension distribution of the strip,and it rotates at high speed in real time in contact with the strip during the working process.The surface of the roll is not only subjected to periodic alternating load of the strip,but also has the phenomenon of slippage and wear due to different speed from the strip.Unlike ordinary cold rolls,plate rolls are perforated from the side near the roll surface,sensors are installed and a large preload force is applied,and the roll surface undergoes elastic deformation of several tens of microns,which requires a certain surface hardness and wear resistance as well as a certain toughness,i.e.,the plate roll hardness,toughness and wear resistance are coordinated with each other.In this paper,we use numerical simulation to simulate the induction quenching process of plate rolls and optimize the heat treatment process according to the requirements of plate rolls in order to improve the service life of plate rolls.Firstly,we use Jmatpro material property simulation software to obtain the material properties,CCT curve and TTT curve required in the analysis of electromagnetic field,temperature field and phase field of the plate shaped roll,and establish a simulation model of the static induction hardening process of the plate shaped roll,and analyze the influence of air gap,current density and current frequency on the processing results from four aspects:magnetic field,electric field,temperature field and phase field,so as to provide a model and process optimization parameters for the subsequent continuous induction hardening of the plate shaped roll.The model is used to establish the basis for the selection of the subsequent continuous induction hardening model and process optimization parameters.Based on the static induction quenching model,the mathematical-motor grid module is used to solve the continuous movement of the induction ring during the continuous induction quenching process.The simulation model of the continuous induction quenching process of the plate roller is established by analyzing the changes of the boundary conditions during the process and using cyclic statements to deal with the cyclic changes of the boundary conditions with time.The effects of induction ring start/stop position,induction ring moving speed and water spray interval on the uniformity of hardened layer and hard layer depth are analyzed to provide reference for the selection of factor levels in the subsequent process parameter optimization.The metallographic and hardness distributions after quenching were observed through model validation experiments.Based on the Maynier hardness prediction model,the martensite hardness after quenching is calculated based on the phase fraction and cooling curve obtained from the simulation,and the hardness calculation model is modified by analyzing the relationship between the calculated and measured hardness values and considering the influence of residual austenite on the martensite and surface hardness.Finally,considering the nonlinear and strongly coupled properties of the electromagnetic induction quenching process,Taguchi’s method was invoked to optimize the process parameters,and the electromagnetic-temperature-tissue field changes of the induction quenching process of the plate-shaped roll before and after optimization were compared,and it was found that the optimized process parameters could effectively reduce the depth of the hardened layer while meeting the surface hardness requirements.