焊接残余应力对高强度钢低匹配对接接头静载强度的影响

Influence of residual stress on static load strength of undermatching butt joint of high strength steel

采用有限元方法研究了焊后拉伸条件下高强度钢等匹配和低匹配对接接头内部应力的变化情况.结果表明,焊后横向和纵向拉伸载荷增至临界失效载荷期间,等匹配和低匹配接头的焊缝区和母材区应力均一直持续增加,但焊缝及近缝母材区应力在焊接残余应力基础上的增加较远端母材区缓慢;最终近缝母材区的应力明显高于远端母材区,未表现出内应力完全调匀的特征;这意味着由于焊接残余应力的存在,高强度钢宽板等匹配焊接结构的静载强度可能略有损失,而高强度钢宽板低匹配焊接结构更将在焊缝低强的影响下损失更大的静载强度.

By means of Finite Element Method( FEM),the change of internal stress in equal-matching and under-matching butt joint of high strength steel on the condition of tensile load after welding was investigated. The results show that the stress level of both weld and base metal in equal-matching and in under-matching butt joint have continued to increase, during transverse and longitudinal tensile loads after welding reached the critical load of failure. But compared with distal base metal,the stress of the welding zone and their adjacent zone increased more slowly on the basis of welding residual stress. In the end,the stress in base metal zone near the seam was significantly higher than that in the distal base metal zone,and which didn't exhibit the feature of the internal stress complete homogenization. This means that the static load strength of equal-matching welded structure of high strength steel wide plate might reduce a little by Influence of the welding residual stress, and the static load strength of under-matching welded structure of high strength steel wide plate reduced more under the reason of low strength weld seam.