感应加热过程中工件表层温度分布及机理分析

Temperature distribution in surface layer of workpiece during induction heating process and its mechanism analysis

采用热模拟试验研究了大截面圆柱工件在感应加热过程中的磁场和温度场分布,探讨了工件内的温度分布以及温度随时间的变化规律。试验结果表明:感应线圈中工件侧的磁场分布受工件内的涡流影响较大,由于磁场的叠加作用,工件表面磁场分布在相对于线圈的中部位置出现最大值。根据圆柱工件表面的温度变化规律得出3个阶段,第一阶段由于热量损失工件次表面温度最高;第二阶段工件温度达到居里点,工件的物性参数发生变化导致表面温度最高;第三阶段温度波峰依次波动向内传递。

Distribution of magnetic field and temperature in large cylindrical workpiece during induction heating process were investigated by thermal simulation experiment,and the temperature distribution in the workpieces and its variation was discussed.The experimental results show that the magnetic distribution is greatly affected by eddy current nearby the workpieces.Due to the principle of magnetic field superposition,the maximum magnetic field value on surface of the workpieces appears in the middle position relative to the loop.According to the surface temperature variation of cylindrical workpieces,the heating process can be divided three stages.In the first stage,the maximum temperature appears in the sub-surface layer of the workpiece due to the heat loss,in the second stage,the maximum temperature appears on the surface layer because of the temperature reaching to the courier point and resulting in the change of its physical parameters;in the third stage,the maximum temperature value transmits to inside in a fluctuant style.