9Cr2凸模半埋藏疲劳裂纹电磁热止裂的实验与模拟研究  

Experimentation and numerical simulation analysis on half-embedding crack preventing in metal die of 9Cr2 steel using electromagnetic heating

作　　者：付宇明[1] 郑丽娟[1] 

机构地区：[1]燕山大学机械工程学院,秦皇岛066004

出　　处：《塑性工程学报》2006年第6期70-73,共4页Journal of Plasticity Engineering

基　　金：国家自然科学基金资助项目(50675190);河北省自然科学基金资助项目(599255)

摘　　要：电磁热效应止裂技术的发展为金属模具中半埋藏裂纹的止裂问题提供了有效的解决途径。文章采用实验和数值模拟分析方法研究了对带有半埋藏裂纹的9Cr2凸模进行脉冲放电,实施电磁热止裂。实验结果表明,脉冲放电瞬时半埋藏裂纹尖端附近金属温升超过熔点,裂尖熔化形成焊口,并且由于裂纹是半埋藏状态,熔化的金属在裂尖处形成堆焊,其周围发生有利于遏制裂纹扩展的组织细化,有效地遏制了裂纹的扩展;数值模拟结果表明,脉冲放电瞬间,裂纹尖端附近很小的区域内,温度和温度梯度变化极大,裂纹尖端金属迅速熔化,导致半埋藏裂纹尖端曲率半径增加几个数量级,数值模拟分析结果与实验结果相吻合。The progress of crack prevention technology using electromagnetic heating has taken an effective way to prevent haltembedding cracks in a metal die from propagating. Experimentation and numerical simulation are proposed for studying half embedding crack prevention in metal die of 9Cr2 steel by pulse current discharge. The experiment surveys show that the temperature around the crack tip grows up instantly above the melting point of the metal. The crack tip may be melted, the deposit joints can be formed because of the half-embedding crack exiting in metal die. The microstructure was analyzed around the crack tip after crack arresting, the super fine structure around crack tip appears too. So the formation of the main crack source will be prevented and the goal of crack preventing can be reached. The numerical simulation shows that the temperature and temperature grads changing enormously around the half embedding crack tip instantly, the crack tip may be melted. The radius of curvature around the crack tip will be increased by some orders of magnitude instantly. The temperature field results of numerical simulation correspond to the results of experiment analysis.

关 键 词：电磁热效应 脉冲放电 半埋藏裂纹 止裂 实验研究 数值模拟 金属凸模 

分 类 号：TG385.2[金属学及工艺—金属压力加工] TG315.2