BS960E高强钢激光-电弧复合焊接头氢脆行为研究

Hydrogen Embrittlement Behavior of BS960E High Strength Steel Laser-Arc Hybrid Welded Joint

氢脆具有很强的微观组织敏感性,威胁着各类高强结构材料的安全服役。采用激光-电弧复合焊工艺对BS960E型高强钢进行焊接,并对接头在原位电化学充氢的条件下进行慢应变速率(10^(-5)s^(-1))拉伸试验,结合微观组织和断裂特征进行分析并对接头的氢脆行为进行研究。结果表明,焊接热循环所形成的富马氏体中的细晶区可以使接头表现出一定的氢脆敏感性,马氏体较大的氢扩散系数和较低的氢溶解度以及氢在晶界上的快速扩散是引起接头对氢脆敏感的主要原因,通过控制焊接工艺参数可抑制焊接热循环所引起的马氏体转变量,能够降低BS960E型高强钢激光-电弧复合焊接头的氢脆敏感性。

Hydrogen embrittlement has strong microstructural sensitivity,which threatens the safe service of all kinds of high strength structural materials.BS960E high strength steel is welded by laser-arc composite welding process,and the joints are subjected to slow strain rate(10^(−5)s^(−1))tensile test under the condition of in-situ electrochemical hydrogen charging.The microstructure and fracture characteristics of the joints are analyzed,and the hydrogen embrittlement behavior of the joints is studied.Results show that the welding thermal cycle of rich martensite formed by fine grain area can make joint show some hydrogen embrittlement sensitivity,martensite higher hydrogen diffusion coefficient and lower hydrogen solubility and rapid diffusion of hydrogen on the grain boundary is the main cause of joint is sensitive to hydrogen embrittlement,by controlling the welding process parameters can inhibit the welding thermal cycle caused by the martensitic transformation,it can reduce the hydrogen embrittance sensitivity of BS960E high strength steel laser-arc composite welding joint.