(1. 西安理工大學(xué) 材料科學(xué)與工程學(xué)院，西安 710048；
2. 中航西安飛機(jī)工業(yè)集團(tuán)股份有限公司，西安 710087)
摘 要: 為了優(yōu)化銅/鋼復(fù)合件的焊接工藝，提高焊接接頭的力學(xué)性能，采用S201焊絲對(duì)T2-Y/Q345B異質(zhì)材料進(jìn)行不同工藝窗口下的熔化極氣體保護(hù)焊(GMAW)試驗(yàn)，并且利用金相、掃描以及拉伸、硬度等試驗(yàn)研究了不同焊接工藝對(duì)銅/鋼焊接接頭組織及性能的影響。結(jié)果表明：對(duì)T2-Y紫銅母材進(jìn)行焊前預(yù)熱處理有利于提高焊縫金屬的鋪展性。同時(shí)，不同的保護(hù)氣體對(duì)接頭質(zhì)量的影響也較大。銅側(cè)熱影響區(qū)(HAZ)主要由孿晶組織組成，孿晶沿著垂直于熔合線方向生長(zhǎng)。另外，在電弧力及濃度梯度的作用下焊縫中元素得到了充分?jǐn)U散，其中，F(xiàn)e元素對(duì)焊縫金屬具有第二相強(qiáng)化作用，從而導(dǎo)致焊縫硬度高于銅側(cè)母材。接頭抗拉強(qiáng)度最高達(dá)224.1 MPa，達(dá)到銅側(cè)母材強(qiáng)度的90%以上。銅側(cè)熱影響區(qū)晶粒粗化，成為焊接接頭的薄弱環(huán)節(jié)。
關(guān)鍵字: 異質(zhì)接頭；預(yù)熱處理；微觀組織；力學(xué)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
