2A14铝合金人孔法兰环焊缝接头断裂失效分析  

Fracture Failure Analysis of 2A14 Aluminum Alloy Manhole Flange Ring-welded Joint

作　　者：淡婷 李晓光 佟玮 武静 张国庆 王兵 DAN Ting;LI Xiaoguang;TONG Wei;WU Jing;ZHANG Guoqing;WANG Bing(Capital Aerospace Machinery Company,Beijing 100076,China;China Academy of Launch Vehicle Technology,Beijing 100076,China)

机构地区：[1]首都航天机械有限公司,北京100076 [2]中国运载火箭技术研究院,北京100076

出　　处：《热加工工艺》2024年第23期48-51,共4页Hot Working Technology

摘　　要：采用断口扫描、金相检查、硬度测试等方法对某型火箭二级燃箱前底2A14铝合金人孔法兰环焊缝低压断裂开展失效分析。结果表明,断裂起源于瓜瓣小端人孔法兰环焊缝背面余高与母材过渡的焊趾应力集中区,沿法兰侧熔合线扩展撕裂。断裂部位人孔法兰环打底焊缝区存在较多焊接疏松缺陷,盖面焊缝存在大量焊接气孔;法兰侧熔合线附近基体组织流线沿着壁厚方向,与焊缝组织流线基本垂直,二者交界部位为受力薄弱处;并且此瓜瓣小端在二级燃箱前底的位置有多道焊缝等复杂结构,最终多重因素导致人孔法兰环焊缝在低压状态下开裂。Failure analysis of low-pressure fracture of 2A14 aluminum alloy manhole flange ring-welded joint in the front bottom of the second stage combustion box of a certain rocket was carried out by means of fracture scanning,metallographic inspection,hardness test and other methods.The results show that the fracture originates from the stress concentration area of the weld toe that transitions from the remaining height of the back of the small-end manhole flange ring weld of the melon petal to the base metal,and expands and tears along the fusion line of the flange side.There are lots of welding porosity defects in the manhole flange ring back weld zone of the fracture site,and there are a large number of welding pores in the cover weld.The flow line of the matrix structure near the fusion line at flange side is distributed along the wall thickness direction,which is basically perpendicular to the flow line of the weld structure,and the junction of the two parts is the weak position.Moreover,the small end of the melon petal is on the verge of a complex structure with multiple welds at the front bottom of the secondary combustion box,and finally multiple factors cause the manhole flange ring weld to crack at low pressure.

关 键 词：2A14铝合金 应力集中 焊接缺陷 流线 

分 类 号：TG441.7[金属学及工艺—焊接]