6061-T6铝合金/SPCC冷轧钢激光熔钎焊特性研究  

Study on Characteristics of Laser Welding-brazing of 6061 Aluminum Alloy to SPCC Cold Rolled Steel

作　　者：张建勋[1] 江旭 徐甄真 张贵锋[1] ZHANG Jianxun;JIANG Xu;XU Zhenzhen;ZHANG Guifeng(State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University,Xi’an 710049)

机构地区：[1]西安交通大学金属材料强度国家重点实验室,西安710049

出　　处：《机械工程学报》2020年第6期41-49,共9页Journal of Mechanical Engineering

基　　金：国家自然科学基金资助项目(51875442)。

摘　　要：针对2 mm厚的6061-T6铝合金与SPCC冷轧钢板,采取填丝激光熔钎焊方法,研究预涂钎剂、坡口角度、坡口形貌、钎料成分对熔钎焊接头的组织成分及力学性能的影响。结果表明,预涂Nocolok钎剂可以显著改善钎料的润湿性能;在钢母材侧预制60°坡口比预制45°坡口时的激光熔钎焊接头力学性能更好;当对钢母材预制60°坡口时,在激光功率、焊接速度、送丝速度、离焦量、光斑中心的偏移距离分别为3.1 k W、0.5 m/min、2 m/min、-8 mm、+0.6 mm时,以Al-Cu焊丝作为填充钎料,界面形成短须状的Fe-Al金属间化合物层,厚度在5~8μm,Cu元素以置换Fe元素的方式固溶在Fe-Al金属间化合物相中改善其脆性,接头的平均及最大抗拉强度分别为147 MPa、159 MPa;以Al-Mg焊丝为填充钎料时,界面形成锯齿状的Fe-Al金属间化合物层,厚度在8~12μm,Mg元素仅聚集在脆性相外侧,对Al-Fe脆性相的生长无明显抑制作用,在激光功率为3 k W时,接头的平均抗拉强度为118 MPa;以Al-Si焊丝为填充钎料时,界面形成小锯齿状的Fe-Al金属间化合物层,厚度在3~4.5μm,Si元素将固溶在Fe-Al金属间化合物相中抑制其生长,在激光功率为3 k W时,接头的平均抗拉强度为129 MPa。2 mm-thick 6061-T6 aluminum alloy and SPCC cold-rolled steel plate are used to obtain aluminum steel composite joints with both fusion and brazing characteristics by means of wire filling laser brazing method. The influences of pre-coated flux, groove bevel angle, bevel morphology and solder composition on the microstructure and mechanical properties of brazing joint are studied. The results show that pre-coating flux can greatly improve wettability of filler metal. The mechanical properties of laser brazing joint are better when 60° groove is prefabricated on the side of steel base metal than when 45° groove is prefabricated.. When the prefabricate groove angle of steel material is 60°, and the laser power, welding speed, wire feeding speed, laser defocusing amount, offset center of the laser spot center are 3.1 k W, 0.5 m/min, 2 m/min,-8 mm, +0.6 mm, respectively, with ER2319 Al-Cu filler metal, the average and maximum tensile strength of the joint are respectively 147 MPa and 159 MPa, the interface layer presents short whisker shape, the interface layer is 5-8 μm in thickness, the Cu element is dissolved in Al-Fe brittle phase by replacing Fe elements to reduce its brittleness. With ER5356 Al-Mg filler metal, the average tensile strength of the joint is 118 MPa when the laser power is 3 k W, the interface layer presents coarse saw tooth shape, and consists of Fe Al2, Fe2 Al5 and Fe Al3 phase, the interface layer is 8-12 μm in thickness, the Mg element is gathered at the outside of brittle phase, and it has no obvious inhibitory effect on the growth of Al-Fe brittle phase;with ER4043 Al-Si filler metal, the average tensile strength of the joint is 129 MPa when the laser power is 3 k W, the interface layer presents small saw tooth shape, the interface layer is 3-4.5 μm in thickness, the Si element is dissolved in Al-Fe brittle phase to inhibit its growth.

关 键 词：铝钢接头 激光熔钎焊 预涂钎剂 界面结构 力学性能 

分 类 号：TG456[金属学及工艺—焊接]