不同焊丝对Al-6Mg-0.7Mn-0.2Er-0.12Zr合金板材焊接性能的影响

Effect of different welding wires on welding properties of Al-6Mg-0.7Mn-0.2Er-0.12Zr alloy sheet

分别以ER5E61、ER5B71铝合金焊丝为填充材料,采用脉冲TIG焊接方法对4 mm厚的Al-6Mg-0.7Mn-0.2Er-0.12Zr合金板材进行对接焊接试验,对比两种铝合金焊丝焊接接头的显微组织和力学性能。结果表明:当焊接电流为140 A时,两种焊丝均可实现单面焊双面成形。采用ER5E61铝合金焊丝焊接,焊接接头的屈服强度为177 MPa,抗拉强度为335 MPa,伸长率为12.15%,焊接系数为87%;采用ER5B71铝合金焊丝焊接,焊接接头的屈服强度为182 MPa,抗拉强度为343 MPa,伸长率为14.11%,焊接系数为90%。由于ER5B71铝合金焊丝中复合添加的Sc、Zr元素进入焊缝组织中,析出的Al_(3)(Sc, Zr)粒子的晶格类型及晶格常数与铝基体的极为相似,错配度极小,当焊丝熔化进入焊缝时,起到了较好的晶粒细化效果,提高了焊接接头的强度。

The butt welding test of 4 mm-thick Al-6Mg-0.7Mn-0.2ER-0.12Zr alloy sheet was carried out by pulse TIG welding with ER5E61 and ER5B71 Al alloy welding wires as filler materials.The microstructure and mechanical properties of the two Al alloy welded joints were analyzed.The results show that when the welding current is 140 A,single-side welding and double-side forming can be realized on both welding wires.When the ER5E61 Al alloy welding wire is used,the yield strength,tensile strength,elongation and welding coefficient,are 177 N/mm^(2),335 N/mm^(2),12.15%and 87%,respectively.When ER5B71 Al alloy welding wire is used,the yield strength is 182 N/mm^(2),the tensile strength is 343 N/mm^(2),the elongation is 14.11%,and the welding coefficient is 90%.Because the.added Sc and Zr elements enter into the weld microstructure of the ER5B71 Al alloy welding wire,the crystal lattice of precipitated Al_(3)(Sc,Zr)particles are very similar to that of the Al matrix,with little mismatch.When the welding wire melts into the weld joint,it plays a great role in grain refinement and improves the strength of the welding joint.