摘要
以ER4043铝硅焊丝为填充金属,研究了Q235钢螺柱与7A52铝合金板CMT焊接工艺,在焊接电流115~135 A,电弧电压14.5~16.5 V,焊接速度0.3 m/min条件下,焊接过程稳定,焊缝成形连续美观.结果表明,7A52铝合金侧熔合区界面为熔焊特征,铝母材发生熔合,熔合良好;钢螺柱侧熔合区为钎焊特征,界面存在反应层,由靠近钢螺柱的Fe2Al5层和靠近焊缝侧的Fe Al3层组成,整体反应层厚度由根趾向焊趾方向逐渐减小.焊趾部位出现富镍区,主要由Al3Ni的共晶组织及少量Al3Ni2组成.与无镀镍层焊缝比较表明,镀镍层在焊接过程的行为降低了界面反应层厚度,且通过形成富镍区,降低了接头的脆性,使接头抗剪强度提高了15%~19%,最高达到146.9 MPa,满足了高强铝合金螺柱焊接的质量要求.
Q235 steel studs and 7A52 aluminum alloy were joined by cold metal transfer(CMT) welding method with Al-Si alloy wire(ER4043) as the filler metal.Good weld forming with stable welding process was obtained under the welding current of 115-135 A,arc voltage of 14.5~16.5 V,welding speed of 0.3 m/min.The microstructure of the joint was studied by means of scanning electron microscope(SEM) and energy dispersive x-ray(EDX).The results showed that fusion welding interface was formed in the 7A52 aluminum alloy fusion zone,and reaction layer was formed in the steel stud fusion zone which grew thinner from the root toe area to weld toe.The reaction layer was composed of Fe_2Al_3 near the steel stud and FeAl_3 near the weld metal.Nickel-rich zone was formed in the weld toe area of the fillet weld,which was composed by eutectic structures of Al and Al_3Ni,and a small amount of Al_3Ni_2,Comparing with the microstructure and mechanical properties of joints without Ni coating,the results showed that the properties of Ni coating during the welding process decreased the thickness of reaction layer and the brittleness of the joint.The highest shearing strength was146.9 MPa,rising by 15%- 19%as compared with joints without Ni coating,which had met the requirements of high strength Al alloy stud welding.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2016年第4期24-28,130,共5页
Transactions of The China Welding Institution
基金
国防基础科研计划资助项目(A2620110005)
关键词
7A52铝合金
熔钎焊
螺柱
金属间化合物
7A52 aluminum alloy
welding-brazing
steel stud
intermetallic compounds
