高强度耐候钢Q355对接接头多次焊修力学行为研究

Influence of multiple repair welding on mechanical properties of Q355GNHD butt joint

通过焊接工艺评定试验以及疲劳试验,分析高强度耐候钢Q355GNHD正常对接接头和3次焊修接头的显微组织、常规力学性能以及疲劳结果差异。结果表明:3次焊修接头熔合良好,显微组织未见马氏体;3次焊修焊接接头和正常焊接接头的拉伸、弯曲及硬度等常规力学性能未见明显差异;3次焊修接头过热区组织粗大,冲击功有所降低,但均满足标准规定的焊接接头技术条件;两种焊接接头的疲劳性能相近,符合设计要求。

Based on the welding procedure qualification and fatigue tests,the difference of conventional microstructure,mechanical properties and fatigue between Q355 GNHD with normal butt joint and three times repair welding joint were analyzed.The results show that the joint of three times repair welding fuses well,and no martensite microstructure was found in the welding joint. The conventional mechanical properties such as tension,bend and hardness make no difference between the two different welding joints,the microstructure of the overheated zone of the three times welding repair joint is coarse,and the impact energy is reduced. However,all results satisfy the technical requirements of welding joint that the standard regulated.The fatigue strength of three times repair welding joint close to normal welding joint,which both satisfy the design requirements.