摘要
针对某2A14-T6铝合金焊接结构在承压试验中发生接头断裂行为开展失效分析,采用断口扫描、宏观形貌检测、焊缝金相分析、焊接结构分析及力学旁证试验等方法,对其进行了断裂原因及机理研究。试验结果表明:焊缝断裂部位存在密集的显微气孔和少量组织疏松缺陷,降低了接头有效承载面积和组织性能,是焊缝断裂失效的主要原因;起裂源区位于焊缝打底焊漏台阶形貌焊趾处,该处接头存在过渡急剧,引起应力集中,是导致焊缝断裂失效的直接原因。在焊接工艺方面,应通过优化焊接工装、细化焊接过程控制等方式提高氦弧焊接过程的稳定性,减少空气侵入电弧,进而降低焊缝气孔率;同时应重视焊缝焊趾形貌的精细化修整,保证接头圆滑过渡,避免出现应力缺口效应。
Failure analysis was carried out for the joint fracture behavior of a 2A14-T6 aluminum alloy welded structure in the pressure test.Fracture causes and mechanisms were studied by fracture scanning,macroscopic morphology detection,weld metallographic analysis,welded structure analysis and mechanical side-validation test.The experimental results show that there are dense microscopic pores and a small amount of porosity defects in the weld fracture site,which reduces the effective bearing area and microstructure performance of the joint,and is the main cause for the fracture failure of the weld.The crack initiation zone is located in the weld toe of weld backing welded leakage step profile,where there is a sharp transition for the joint,which causes stress concentration,and is the direct cause of weld fracture failure.In terms of the welding process,the stability of helium arc welding process should be improved by optimizing welding equipment and refining welding process control,so as to reduce air intrusion into the arc and reduce weld porosity.At the same time,attention should be paid to the fine repair of weld toe profile to ensure the smooth transition of the joint and avoid the stress notch effect.
作者
肖宏
李克梅
刘含伟
史朝军
淡婷
王亚森
史蕊
李洋
XIAO Hong;LI Kemei;LIU Hanwei;SHI Chaojun;DAN Ting;WANG Yasen;SHI Rui;LI Yang(Tianjin Aerospace Long March Rocket Manufacturing Co.,Ltd.,Tianjin 300462,China;Capital Aerospace Machinery Company,Beijing 100076,China)
出处
《压力容器》
北大核心
2022年第4期66-74,共9页
Pressure Vessel Technology
基金
科技部国家科技重大专项(民用)(2018ZX04013001)。
作者简介
肖宏(1986),男,高级工程师,研究方向为运载火箭燃料贮箱自动化焊接技术,通信地址:300462天津市经济技术开发区西区夏青路199号天津火箭公司南门,E-mail:xiaohng332@126.com。
