(1. 西安理工大学 材料科学与工程学院，西安 710048；
2. 中航西安飞机工业集团股份有限公司，西安 710087)
摘 要: 为了优化铜/钢复合件的焊接工艺，提高焊接接头的力学性能，采用S201焊丝对T2-Y/Q345B异质材料进行不同工艺窗口下的熔化极气体保护焊(GMAW)试验，并且利用金相、扫描以及拉伸、硬度等试验研究了不同焊接工艺对铜/钢焊接接头组织及性能的影响。结果表明：对T2-Y紫铜母材进行焊前预热处理有利于提高焊缝金属的铺展性。同时，不同的保护气体对接头质量的影响也较大。铜侧热影响区(HAZ)主要由孪晶组织组成，孪晶沿着垂直于熔合线方向生长。另外，在电弧力及浓度梯度的作用下焊缝中元素得到了充分扩散，其中，Fe元素对焊缝金属具有第二相强化作用，从而导致焊缝硬度高于铜侧母材。接头抗拉强度最高达224.1 MPa，达到铜侧母材强度的90%以上。铜侧热影响区晶粒粗化，成为焊接接头的薄弱环节。
关键字: 异质接头；预热处理；微观组织；力学性能
（1. College of Material Science and Technology, Xi’an University of Technology, Xi’an 710048, China;
2. AVIC Xi’an Aircraft Industry Group Co., Ltd., Xi’an 710087, China）
Abstract:In order to optimize the welding process of copper/steel composite parts and improve the mechanical properties of welded joints, the GMAW test of dissimilar material around T2-Y and Q345B under different welding technology was carried out by using S201 copper wire, and the influence of different welding processes on the microstructure and mechanical property of copper and steel welded joint was studied by metallographic test, scanning electron microscope test, tensile test and hardness tests. The results show that the preheating treatment of T2-Y copper base material is beneficial to improve the spreadability of weld metal, and the different protective gas also has a great influence on the joint quality. The heat affected zone on the copper side is mainly composed of twin crystal that grows perpendicular to the direction of fusion line. In addition, under the action of arc force and concentration gradient, the elements in the weld are fully diffused, among them, Fe element has the second phase strengthening effect on the weld metal, so that the hardness of the weld is higher than that of the base metal on the copper side. The maximum tensile strength of the joint is 224.1 MPa, which is more than 90% of that of the copper side base metal. Due to the serious grain coarsening in HAZ grain on the copper side, this zone becomes the part with poor performance.
Key words: dissimilar joints; preheating treatment; microstructure; mechanical property
