Effect of multiple welding repairs on operational safety of P92 steel welded joints
P92 steel has been widely used in ultra-supercritical power generation units,however,the effect of mul-tiple 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 me-chanical 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 unre-paired one.The strength of the repaired joints with homogeneous welded materials is equivalent to that of unre-paired 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.
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