基于电磁热耦合的Cr12MoV模具钢感应淬火数值模拟

Numerical simulation on induction hardening of Cr12MoV die steel based on electromagnetic thermal coupling

采用有限元数值模拟方法,以Cr12MoV模具钢为研究对象,研究感应加热过程中电源频率、电流密度以及感应线圈移动速度等工艺参数对工件表面温度场的影响。根据麦克斯韦方程组和非稳态导热微分方程,建立电磁场与温度场耦合的移动式双回路线圈感应加热模型,计算得到不同工艺参数下工件表面温度场,并通过感应淬火试验对模拟计算结果进行验证。结果表明,工件表面中心处的温升曲线为双峰曲线。温升速率和幅值随着电源频率和电流密度的增大而增大,随着感应线圈移动速度的增大而减小。对淬火后工件厚度方向进行硬度分析,对比发现模拟计算获取的高温区深度大致与淬硬层深度保持一致。试验测量的温升曲线与模拟计算结果基本吻合,最大误差约为7%,表明可以通过数值模拟计算方法对实际应用中的工艺参数进行优化,进而实现对工件淬火后淬硬层深度和硬度的精确控制。

Finite element numerical simulation method was adopted to study the effects of power frequency,current density and induction coil moving speed on surface temperature field of the workpiece during induction hardening for the Cr12MoV die steel.According to Maxwell's equations and non⁃stationary thermal conductivity differential equations,a moving dual⁃loop induction coil model coupled with electromagnetic field and temperature field was established,by which the temperature field on surface of the workpiece was calculated.And the simulation results were verified by induction hardening experiments.The results show that the temperature rising curve at the center of the workpiece surface is a bimodal curve.The rate and amplitude of temperature rising increase with the increase of power frequency and current density,while decrease with the increase of induction coil moving speed.Through the hardness analysis in the thickness direction of the workpiece after hardening,it is found that the depth of the high⁃temperature region obtained by simulation calculation is roughly consistent with the depth of the hardened layer.The temperature rising curve measured in experiments basically matches the numerical simulation results,with a maximum error of about 7%,which shows that the process parameters for practical application can be optimized by numerical simulation method,realizing the precise control of depth of hardened layer and hardness of the workpiece after hardening.