某分隔屏过热器换位弯内弧外表面裂纹的产生原因  

Causes of Surface Cracks on Outer Surface of Inner Arc of Transposition Bend of Partition Platen Superheater

作　　者：张斌 李玲[1,2] 彭波 王云[1,2] 董彬 王静 ZHANG Bin;LI Ling;PENG Bo;WANG Yun;DONG Bin;WANG Jing(Beijing Huake Tonghe Technology Co.,Ltd.,Beijing 102200,China;North China Electric Power Research Institute Co.,Ltd.,Beijing 100045,China;Beijing Shengling Electric Power Technology Co.,Ltd.,Beijing 102206,China)

机构地区：[1]北京华科同和科技有限公司,北京102200 [2]华北电力科学研究院有限责任公司,北京100045 [3]北京盛凌电力科技有限公司,北京102206

出　　处：《腐蚀与防护》2023年第7期86-89,104,共5页Corrosion & Protection

摘　　要：通过宏观检查、化学成分分析、力学性能测试、显微组织观察等,对某600 MW亚临界机组分隔屏过热器管换位弯内弧外表面裂纹的产生原因进行分析。结果表明:腐蚀性S元素的富集浓缩腐蚀了分隔屏过热器管基体,形成“显微缺口”,萌生微裂纹;外表面脱碳层的存在,为裂纹扩展提供了有利条件;微裂纹在S腐蚀环境和热疲劳循环载荷协同、交互作用下不断扩展,最终产生腐蚀性热疲劳裂纹。The causes of surface cracks on the outer surface of inner arc of a transposition bend of partition platen superheater tube of a 600 MW subcritical unit were analyzed through macroscopy examination,chemical composition analysis,mechanical property testing,microstructure observation,etc.The results showed that the enrichment concentration of corrosive S element corroded the substrate of the tube,forming"micro notches"and initiating microcracks.The presence of a decarburized layer on the outer surface provided favorable conditions for crack propagation.Microcracks continued to propagate under the synergistic and interactive effects of S corrosion environment and thermal fatigue cyclic loads,ultimately resulting in corrosive thermal fatigue cracks.

关 键 词：过热器 外表面裂纹 腐蚀性热疲劳 

分 类 号：TG142[一般工业技术—材料科学与工程]