SPCC钢与NdFeB永磁体的激光点焊  

Laser spot welding of SPCC steel to NdFeB magnets

作　　者：常保华[1] 白少俊[1] LI Xiaogang DING Yuquan 张骅[1] 都东[1] ZHOU Yunhong 

机构地区：[1]清华大学机械工程系,先进成形制造教育部重点实验室,中国北京100084 [2]滑铁卢大学机械工程系,滑铁卢N2L3G1,加拿大

出　　处：《清华大学学报（自然科学版）》2008年第11期1904-1907,共4页Journal of Tsinghua University(Science and Technology)

基　　金：国家自然科学基金资助项目(50628506,50705049);清华大学先进成形制造教育部重点实验室开放基金项目(2006010)

摘　　要：在电子、汽车及音响器件的制造中,稀土永磁材料N dF eB与钢构件之间连接通常采用机械连接或粘接的方法,而关于钢与磁材料焊接的研究与应用还未见报道。为实现钢磁异质材料之间快速和高质量的连接,该文探索采用激光点焊方法连接SPCC钢与N dF eB永磁体,并对接头的形成过程、硬度、强度和断裂行为进行了研究。结果表明:激光点焊过程中,两种母材受热快速熔化、混合、凝固形成接头;接头中硬度分布不均匀,热影响区的硬度比N dF eB母材低,熔核内熔核线附近区域硬度最高,熔核中部硬度最低;接头断裂应力可达到磁体强度的75%;熔核与磁体界面上容易出现热裂纹,结合较弱,因此剪切试验中接头主要从这一区域发生断裂,断裂为晶间断裂,是典型的脆性断裂。Mechanical fastening or adhesive bonding is generally used to join NdFeB pernlanent magnets to steel components, with no research on the welding of magnets to steel. Here, laser spot welding was used to join a NdFeB permanent magnet to SPCC （steel plate cold commercial） steel in a high speed, high quality joining of dissimilar magnet and steel materials. The joint formation mechanism, hardness, strength, and fracture behavior are analyzed. The results show that during the welding process, the two base metals quickly melt, mix and then solidify to form a weld that joins the two specimens together, but that the joint hardness is not uniform with the heat affected zone having lower hardness than the NdFeB base metal. Within the nugget, the region adjacent to the fusion line has the highest hardness while the middle part of the nugget has the lowest hardness in the joint. The maximum fracture stress of the joint is about 75% the strength of the magnet. Hot cracks tend to occur at the interface between the nugget and the magnet base metal, with the cracks propagating and leading to joint failure during shear tests. The fracture is a typical intergrannular brittle fracture.

关 键 词：NDFEB永磁体 激光点焊 异质材料 热裂纹 脆性断裂 

分 类 号：TG402[金属学及工艺—焊接]