多次焊接修复对P92钢焊接接头运行安全的影响

Effect of multiple welding repairs on operational safety of P92 steel welded joints

P92钢已被广泛用于超超临界发电机组中,但多次修复工艺对P92钢焊接接头运行安全性的影响鲜有人研究。研究了多次焊接修复对P92焊接接头组织和性能的影响,并采用扫描电镜,透射电镜和力学性能测试等方法对多次焊接修复后的P92钢焊接接头的显微组织和力学性能进行检测,结果表明:正常焊接工艺、同质焊材2次和3次修复焊接接头的常规力学性能满足相关标准的要求。923 K时效后,2种修复状态的焊接接头强度和焊缝冲击韧性的变化趋势与未修复的焊接接头的基本一致,同质焊材修复接头强度与正常接头相当。蠕变试验结果表明,相同的试验应力下,修复3次焊接接头的蠕变性能低于正常热处理接头。因此可通过多次焊接对P92钢焊接接头进行修复。

P92 steel has been widely used in ultra-supercritical power generation units,however,the effect of multiple repair processes on the operation safety of P92 steel welded joints was rarely studied.The effect of multiple welding repairs on the microstructure and properties of P92 welded joints was studied,and the microstructure and mechanical properties of P92 steel welded joints after multiple welding repairs were tested using scanning electron microscopy,transmission electron microscopy,and mechanical property testing.The results show that,the mechanical properties of the welded joints repaired two or three times by normal welding process and homogeneous welded materials meet the requirements of relevant standards.After aging at 923 K,the changes of strength and impact toughness of the welded joints of the repaired welded joint are basically consistent with those of the unrepaired one.The strength of the repaired joints with homogeneous welded materials is equivalent to that of unrepaired welded joints.The creep test results show that the creep performance of the triple repaired welded joint is lower than that of the unrepaired welded joint.Therefore,P92 steel welded joints can be repaired by multiple welding.