为分析不同激励条件下不同材料感应加热特性，采用有限元仿真软件分析铁磁性材料45#钢和非铁磁性材料不锈钢感应加热时的涡流分布和温度分布，发现45#钢趋肤深度很小，裂纹边沿感应电流密度较大；不锈钢趋肤深度受激励电流频率影响很大。随激励电流频率的增大，趋肤深度减小，裂纹边沿感应电流密度增大。涡流的分布和裂纹对热扩散的阻碍作用共同决定裂纹附近温度的分布，并通过实验对仿真结论进行验证，确定两种材料表面裂纹的最佳激励条件。%The surface defect of metallic materials can be detected effectively and accurately by pulsed eddy current thermography. In order to analyze different induction heating characteristics of different materials under different excitation conditions, distribution of eddy current and temperature between magnetic and non-magnetic materials,that is,45# steel and stainless steel, were compared. The result shows that, the surface depth of 45# steel is very small, the density of induced current in crack edge is substantial. The surface depth of stainless steel is influenced greatly by excitation frequency of the current. As frequency increases,the surface depth decreases and the density of current in crack edge increases. The temperature variation is determined by both the distribution of current and the crackˊs hindering for the thermal diffusion. The conclusions were experimentally verified, and the optimum excitation conditions to identify both materialsˊ surface cracks were determined.
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