镁/钢异种金属CMT对接熔钎焊连接机理  

Joining mechanisms of Mg-steel butt welded joints by cold metal transfer method

作　　者：曹睿[1] 朱海霞[1] 王清[2] 董闯[2] 林巧力[1] 陈剑虹[1] 

机构地区：[1]兰州理工大学有色金属先进加工与再利用省部共建国家重点实验室,兰州730050 [2]大连理工大学三束材料改性教育部重点实验室,大连116024

出　　处：《焊接学报》2016年第5期37-40,130,共4页Transactions of The China Welding Institution

基　　金：973计划前期研究专项(2014CB660810);国家自然科学基金资助项目(51265028);大连理工大学三束材料改性教育部重点实验室开放基金资助资目(LABKF1402)

摘　　要：文中用AZ61镁焊丝以及冷金属过渡焊接方法对接形式连接镁合金AZ31和镀锌钢板,在焊接过程中保持焊接速度不变,通过调节送丝速度和对钢板开不同的坡口研究不同焊接工艺参数下焊缝的表面成形、接头的力学性能和微观组织结构.结果表明,通过调节合适的焊接参数以及坡口形式,镁-钢之间能形成焊缝成形美观、接头最大抗拉载荷达到4.02 k N的镁钢对接熔钎焊接头.并且熔钎焊接头包括镁侧的熔焊接头和钢侧的钎焊接头,钎焊接头由两部分组成,一部分是坡口面上的镁与裸钢板之间的钎焊接头,另一部分是镀锌钢板上表面的镁-镀锌钢之间的钎焊接头.镁-镀锌钢侧的钎焊连接主要由靠近镁侧的(α-Mg+Mg Zn)的共晶相,以及靠近钢侧的Fe-Al相反应层实现连接.无镀锌层的钢和镁连接主要依靠焊丝中的微量Al元素扩散到钢表面形成Fe/Al相来实现连接.In this paper,Mg AZ31 sheet and galvanized steel sheet were butt welded and joined by cold metal transfer method with AZ61 Mg wire. Weld appearance,tensile properties and microstructure of Mg-steel butt joints at various welding parameters were investigated by changing wire feed speeds and groove angles. Results indicated that Mg-steel brazed-welded joints with good weld appearance and 4. 02 kN of tensile load can be achieved. And the brazed-welded joint is composed of welded joint at Mg side and brazed joint at steel side. The brazed joint is made of two parts,one is Mg-galvanized steel brazed joint which is located at the top of galvanized steel sheet,and the other is Mg-bare steel brazed joint which is located at the groove side.The Mg-galvanized steel joint brazed interface is composed of two reaction layers with-Mg + MgZ n eutectic phase and Fe / Al reaction layer. The Mg-bare steel brazed interface at the groove side is composed of Fe / Al reaction layer,and Fe / Al phase is diffused and reacted by Al element of the Mg wire and Mg base metal.

关 键 词：镁合金AZ31 镀锌钢 冷金属过渡 熔钎焊 

分 类 号：TG456.9[金属学及工艺—焊接]