某新建锅炉12Cr1MoVG一级过热器爆管失效分析OA

Two months after a newly-built boiler was put into operation,a 12Cr1MoVG first-stage superheater tube burst accident occurred continuously.This paper uses the methods of appearance inspection,dimensional measurement,chemical composition analysis,tensile test,hardness test,metallographic examination and oxide scale thickness measurement to analyze the relevant tube.The results show that the oxide scale thickness,tensile strength and hardness in the blast tube section are all lower than the standard requirements,and the metallographic structure is severely spheroidized.In summary,the cause of the tube leakage of the first-stage superheater is long-term overheating.In the case of overheating,the metallographic structure is abnormally aging,the mechanical properties are reduced,and the thickness of the inner wall oxide scale causes the heat transfer to deteriorate further.When it reaches a certain level,the tube bursts under stress.The cause of long-term overheating is the poor circulation of the medium in the tube.