摘要
采用变极性等离子焊接工艺实现了5mm厚船用A5000系铝合金立向上位置焊接,并分析了接头的组织和力学性能。力学试验显示:接头抗拉强度达到295MPa,延伸率达到10%,断裂位置在熔合线附近;焊缝区和热影响区的显微硬度均低于母材,且焊缝中心处最低。接头金相观察发现:熔合线附近的焊缝为粗大的等轴晶组织,但焊缝区大部分为胞状树枝晶组织,从两侧呈对称生长并在焊缝中心处相遇,热影响区为再结晶组织。利用电子探针分析了拉伸断裂位置附近的成分,发现该区域Mg含量偏低且分布不均匀,固溶强化效果下降,组织和成分的不均匀导致该区域成为接头的薄弱部位。
A5000 series(Al-Mg) aluminum alloy with a thickness of 5 mm for shipbuilding was successfully welded by a variable polarity plasma welding process in a vertical-up position. The microstructure and mechanical properties of the joint were investigated. The ultimate tensile strength of the joint is 295 MPa, the elongation is 10%, and the location of fracture is near the fusion line. The micro hardness of the weld zone and heat affected zone is lower than that of the base metal, and the lowest hardness appears at the center of the weld. The optical micrographs of the joint show that the weld microstructure near the fusion line is a coarse equiaxed grain structure, and most of the weld region is a cellular dendritic structure growing from the two sides to the center, while the microstructure of the heat affected zone is a typical recrystallized structure. The composition around the tensile fracture was analyzed by EPMA, and the results reveal that the content of Mg is low and heterogeneously distributed. The lack and segregation of Mg and non-homogeneous microstructure decrease solution strengthening, resulting in weak areas of the joint.
引文
[1]Staige R A M P,Pietaka A M.Biomaterials[J],2006,27(9):1728
[2]Jian Haigen(蹇海根),Tang Xianmin(唐娴敏),Ou Ling(欧玲)et al.Rare Metal Material and Engineering(稀有金属材料与工程)[J],2016,45(2):415
[3]Yan Dejun(闫德俊),Han Duanfeng(韩端锋),Wang Yi(王毅)et al.The Chinese Journal of Nonferrous Metals(中国有色金属学报)[J],2016,26(10):2066
[4]Huang Yong(黄勇),Fan Ding(樊丁).Transactions of the China Welding Institution(焊接学报)[J],2008,29(1):46
[5]Yang Haifeng(杨海锋),Liang Xiaomei(梁晓梅),Wang Jixiao(王吉孝)et al.Welding&Joining(焊接)[J],2016(6):18
[6]Chang Liyan(常丽艳),Song Xiping(宋西平),Li Hongliang(李宏良)et al.Transactions of the China Welding Institution(焊接学报)[J],2014,35(9):25
[7]Zeng Ping(曾平).Ship and Ocean Engineering(船海工程)[J],2010,39(1):55
[8]Jiang Yi(姜祎),Xu Binshi(徐滨士),Lv Yaohui(吕耀辉)et al.Transactions of the China Welding Institution(焊接学报)[J],2010,31(11):17
[9]Han Yongquan(韩永全),Du Maohua(杜茂华),Chen Shujun(陈树君)et al.Transactions of the China Welding Institution(焊接学报)[J],2010,31(11):93
[10]Zhang Qinlian(张勤练),Yang Chunli(杨春利),Lin Sanbao(林三宝)et al.Transactions of the China Welding Institution(焊接学报)[J],2013,34(9):80
[11]Jiang Yi(姜祎),Liu Ming(刘明),Lv Yaohui(吕耀辉)et al.Transactions of the China Welding Institution(焊接学报)[J],2014,35(10):26
[12]Liu Liming(刘黎明),Shen Yong(沈勇),Zhang Zhaodong(张兆栋).Journal of Mechanical Engineering(机械工程学报)[J],2006,42(5):199
[13]Li Guowei(李国伟),Han Yongquan(韩永全),Chen Furong(陈芙蓉)et al.Transactions of the China Welding Institution(焊接学报)[J],2015,36(10):6
[14]Yu Aiwu(余爱武),Yang Chenggang(杨成刚),He Peng(何鹏)et al.Rare Metal Material and Engineer(稀有金属材料与工)[J],2016,45(3):760
[15]Xu Lianghong(许良红),Tian Zhiling(田志凌),Peng Yun(彭云)et al.Chinese Journal of Lasers(中国激光)[J],2008,35(3):457
[16]Lei Yucheng(雷玉成),Zheng Huijin(郑惠锦).Journal of Jiangsu University of Science and Technology,Natural Science Edition(江苏理工大学学报,自然科学版)[J],2000,21(10):61