汽轮机低压转子1Cr12Ni3Mo2VN不锈钢叶片的开裂原因分析  

Analysis on Cracking Cause of 1Cr12Ni3Mo2VN Stainless Steel Blade in Low Pressure Rotor of Steam Turbine

作　　者：张炜 倪进飞 尤晋 龚光平 卢忠铭 ZHANG Wei;NI Jin-fei;YOU Jin;GONG Guang-ping;LU Zhong-ming(Guangzhou Special Pressure Equipment Inspection&Research Institute,Guangzhou 510663,China)

机构地区：[1]广州特种承压设备检测研究院,广东广州510663

出　　处：《材料保护》2022年第4期203-209,共7页Materials Protection

摘　　要：对某火力发电厂2号汽轮机组末级开裂叶片进行宏观检查、化学成分分析、金相组织以及断口扫描和元素成分能谱分析。结果表明:该叶片裂纹形成属于腐蚀疲劳失效,蒸汽中存在氯、硫等腐蚀介质引起叶片发生电化学腐蚀,在离心拉应力作用下发生沿晶应力腐蚀开裂,形成裂纹源。在腐蚀介质、拉应力和激振力综合作用下,腐蚀疲劳裂纹加速扩展,并最终发生瞬时断裂。Macroscopic examination,chemical composition analysis,metallographic structure,fracture scanning and element composition energy dispersive spectrum analysis were carried out on the cracked blade of the last stage of No.2 steam turbine unit in a thermal power plant.Results showed that the crack formation of turbine blades belonged to corrosion fatigue.The electrochemical corrosion of the blade was caused by corrosive media such as chlorine and sulfur in steam,and then intergranular stress corrosion cracking occurred under the centrifugal tensile stress,forming the crack source.Under the combined effect of corrosive medium,tensile stress and exciting force,the corrosion fatigue crack accelerated to expand and finally broke instantaneously.

关 键 词：汽轮机叶片 疲劳腐蚀 失效分析 

分 类 号：TG172[金属学及工艺—金属表面处理]