摘要
以智能型点焊机为试验平台,研究超级钢点焊接头的组织和显微硬度分布情况.结果表明,普通低碳钢的点焊工艺不适用于超级钢,需附加锻压力,以消除气孔等收缩性缺陷.熔核内部组织结构分别为等轴晶区和胞状晶区;熔核外部的热影响区包括过热区和重结晶区.接头区域的显微硬度明显高于母材组织,主要是由于点焊快冷条件下产生了马氏体组织;而热影响区的组织硬度稍低于熔核中心区域,应是残余应力及再生细晶相互作用的结果.
In this paper,400MPa ultrafine grained steel is welded by intelligent spot welder.The joint＇s microstructure and hardness are studied.The results indicate that the nugget that adopted the spot welding parameters,which are suitable for general low-carbon steel,has shrinkage cavity.The weld defect is conquered by forging force.In the nugget,the microstructure are equiaxed grain and epitaxial grain.In the heat affected zone,the microstructure are overheated structure and secondary solidification structure.The nugget is greatly harder than the base metal,and a little harder than the metal in HAZ.The martensite in the water cooling nugget leads to the former phenomenon,and the latter conclusion is the reciprocal result of welding residual stress and secondary ultrafine grain.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2012年第6期85-88,117,共4页
Transactions of The China Welding Institution
关键词
超细晶粒钢
电阻点焊
焊接工艺
显微组织
ultralfine grained steel
resistance spot weld
welding technology
microstructure
