铝/钢异种金属MIG电弧熔-钎焊接界面应力演变数值分析  

Numerical Analysis of Stress Evolution in MIG Arc Brazing-fusion Welding of Al Alloy to Galvanized Steel Plate

作　　者：秦国梁[1] 耿培皓 陈永 任文建 QIN Guoliang;GENG Peihao;CHEN Yong;REN Wenjian(Key Laboratory for Liquid-Solid Structure Evolution and Processing of Materials,Ministry of Education,Shandong University,Jinan 250061;Aotai Electric Co.,Ltd.,Jinan 250101)

机构地区：[1]山东大学材料液固结构演变与加工教育部重点实验室,济南250061 [2]山东奥太电气有限公司,济南250101

出　　处：《机械工程学报》2021年第2期87-96,共10页Journal of Mechanical Engineering

基　　金：国家自然科学基金资助项目(52075297)。

摘　　要：基于搭接结构造成的电弧热源非对称分布和过热熔滴热焓的热作用特征,建立非对称型四椭圆面热源和均匀体热源的组合热源,并基于热-弹-塑性有限元理论,数值分析1mm厚5052铝合金和2mm厚镀锌钢搭接接头MIG电弧熔-钎焊接应力应变场演变,讨论残余应力分布特征。计算结果表明,随着到焊缝中心的距离增加,镀锌钢母材近钎焊缝区域所受内应力由压应力逐渐转为拉应力。铝侧焊缝区域的残余应力表现为等于室温铝合金屈服强度的拉应力,在焊根处降低为零或转变为压应力。钎焊界面两侧存在较大的残余应力差,不同焊接热输入下界面两侧焊接残余应力差的分布均呈n形,并与钎焊界面剪切强度呈负相关,随着热输入的增大,界面残余应力差增大,而接头剪切强度逐渐下降。Based on the asymmetry of arc heat source due to the overlap structure and the thermal effect of hear enthalpy of metal droplet, a combined heat source model with an asymmetric four-ellipse heat source and a uniform volumetric heat source is established. According to the thermo-elastic-plastic finite element theory, the welding stress/strain evolution in MIG arc brazing-fusion welding of 1 mm thick 5050 Al alloy to 2 mm thick galvanized steel plate is analysed numerically based on the overlap joint, and then the distribution characteristics of residual stress in both sides of brazed interface are studied. The results show that the base metal of galvanized steel close to weld zone is under compressive stress, and the internal stress is gradually transformed into the tensile stress with the increase of distance from weld centre. Residual stress in weld zone at Al alloy side shows the tensile stress that reaches up to the yield strength of Al alloy at room temperature. At the weld toe, the residual stress decreases abruptly to zero or becomes compressive stress. A stress difference exists across the brazed interface, which displays the n-type distribution at different welding heat inputs. There is a negative correlation between the shear strength of brazed interface and residual stress difference at interface. As the welding heat input increases, the increasing of residual stress difference at brazed interface results in the decrease of joint shear strength.

关 键 词：异种材料焊接 熔-钎焊 应力场 温度场 数值模拟 

分 类 号：TG404[金属学及工艺—焊接]