锅炉过热器管弯头开裂失效分析  

Analysis on Cracking Failure of Boiler Superheater Tube Elbow

作　　者：陈兴阳 马琳琳 赵峰霆 宋俊俊 谢浩平 CHEN Xing-yang;MA Lin-lin;ZHAO Feng-ting;SONG Jun-jun;XIE Hao-ping(Zhejiang Academy of Special Equipment Science,Hangzhou 310020,China;Key Laboratory of Special Equipment Safety Testing Technology of Zhejiang Province,Hangzhou 310020,China)

机构地区：[1]浙江省特种设备科学研究院,浙江杭州310020 [2]浙江省特种设备安全检测技术研究重点实验室,浙江杭州310020

出　　处：《材料保护》2021年第10期154-157,共4页Materials Protection

基　　金：浙江省自然科学基金探索项目(LQ20E010001)资助。

摘　　要：某12Cr1MoVG钢锅炉在投入使用数月后发现过热器管弯头处发生开裂。采用光学显微镜、显微硬度计、扫描电子显微镜和能谱仪对锅炉过热器管弯头开裂进行了失效分析。结果表明:过热器管弯头失效的主要原因为碱性环境下的应力腐蚀和氢脆,过热器管弯头在运行过程中局部存在浓缩碱溶液,浓缩碱溶液在高温和水的作用下腐蚀管道内壁并生成微量的氢,氢在残余应力的作用下侵入金属内部并在晶界处聚集引发氢脆,这是造成弯头内壁形成大量沿晶裂纹的根本原因。After a 12Cr1MoVG steel boiler was put into use for several months,it was found that the superheater tube elbow was cracked.The optical microscopy,microhardness tester,scanning electron microscope(SEM)and energy dispersive spectrometry(EDS)were conducted to analyze the cracking failure of boiler superheater tube elbow.Results showed that the main reasons for the failure of superheater tube elbow were alkali environmental stress corrosion and hydrogen embrittlement.During the operation of the superheater tube elbow,there was concentrated alkali solution locally.The concentrated alkali solution corroded the inner wall of the tube under the action of high temperature and water and generated a small amount of hydrogen.Under the action of residual stress,the hydrogen invaded into the metal and accumulated at the grain boundaries and then caused hydrogen embrittlement.This was the fundamental reason for the intergranular cracking of the inner wall of elbow.

关 键 词：过热器 失效分析 碱应力腐蚀 裂纹 

分 类 号：TB31[一般工业技术—材料科学与工程]