汽车滚型轮辋闪光对焊后出现开裂。采用化学成分分析和宏、微观检验等方法对开裂轮辋进行了分析。结果表明：焊缝中存在氧化物夹杂、粗大的魏氏组织及沿晶游离渗碳体,使材质变脆,由此产生较大的内应力促使微裂纹生成,在上述因素下,轮辋在对焊后扩张时产生开裂。

The crack of automobile roll forming rim was analyzed by means of the chemical composition analysis,macrocosmic and microcosmic examination,the experimental results show that the oxide inclusion in fusion areas,widmanstatten structure,and free cementite producing along the grain edge are weak mechanical property in joint. The micro-crack initiated near the beat-affective zone. Under the above factors,the rim was cracking during the expansion.