含半埋藏空间裂纹的Cr12冷冲凹模电磁热止裂分析

Analysis on the Crack Arrest in Cr12 Cold Punch Cavity Die with Half-embedding Spatial Crack by Using Electromagnetic Heating

对内表面含有半埋藏半椭圆裂纹的Cr12冷冲凹模进行了电磁热止裂研究。采用数值分析的方法,对放电瞬间的耦合场进行了分析,给出了半埋藏半椭圆裂纹尖端附近温度场的分布状态;通过ZL-2型放电装置实现了半椭圆裂纹切片试样的止裂实验研究。研究结果表明:脉冲电流放电瞬间,围绕裂纹尖端的金属熔化,钝化了裂尖,得到了超细化的金属组织,提高了裂纹尖端的机械性能,阻止了干线裂纹源的开裂趋势,达到了止裂的目的。在数值模拟研究过程中采用热-电耦合的分析方法,综合考虑了材料非线性、状态变化非线性和几何非线性,数值模拟结果与实验结果比较相符。

The crack arrest in Cr12 cold punch cavity die with half-embedding and half-ellipse crack on inside surface using electromagnetic heating was analyzed. A numerical simulation method was proposed for analyzing the coupled field in cavity die with spatial crack at the moment when the current was switched on. The distribution of temperature field was studied around the crack tips in cavity die with half-embedding and half-ellipse crack. The crack arrest experimental study in cut section of cavity die cut with cracks was conducted on pulse current generator （model ZL-2） developed by the authors. The research results show that the crack tip along the half-ellipse cracks will be melt and the small welded joints can be formed at a small sphere near the crack tips,and the super fine metal structure is gained,the mechanical capability of crack tip is improved. So, the goal of crack pre- venting can be reached. The thermal-electrical coupling theory was applied in numerical simulation, the material nonlinear, state nonlinear and geometry nonlinear problems were discussed in proceeding. The temperature field results of numerical simulation correspond to the experimental ones.