汽轮机阀体表面Stellite合金堆焊层失效分析  

Failure Analysis of A Stellite Alloy Coating on Steam Turbine Valve

作　　者：肖腾 蒋寸才 孔祥夷 王仲强 郭俊杰 王东 XIAO Teng;JIANG Cuncai;KONG Xiangyi;WANG Zhongqiang;GUO Junjie;WANG Dong(Henan Boiler and Pressure Vessel Inspection Technology Research Institute,Zhengzhou 450041,China;College of Mechanical and Electrical Engineering,Henan University of Technology,Zhengzhou 450001,China)

机构地区：[1]河南省锅炉压力容器检验技术科学研究院,河南郑州450041 [2]河南工业大学机电工程学院,河南郑州450001

出　　处：《热加工工艺》2025年第3期139-142,146,共5页Hot Working Technology

基　　金：河南省重点科技攻关资助项目(212102210350);河南工业大学高层次人才科研启动基金项目(2019BS052)。

摘　　要：服役6年后,蒸汽轮机COSTE钢阀体上的Stellite6合金堆焊层发生了脱落。利用焊条电弧焊在COSTE钢上堆焊了Stellite6合金,研究Stellite6堆焊层失效的原因。结果显示:堆焊过程中,COSTE钢对Stellite6合金产生稀释作用,Fe元素在Stellite6近界面处发生了聚集;服役过程中,Fe元素又从钢基体向Stellite6堆焊层进行了长程扩散。过高的Fe含量促使Stellite6堆焊层中α-Co(Cr,Fe,W)固溶体发生共析转变,生成脆性α'-FeCo(Cr,W)体心立方相和σ-CrCo(Fe,W)四方相。在长时间的工作载荷和热应力作用下,这种脆性组织最终导致了Stellite6堆焊层的失效。The Stellite 6 alloy coating on COSTE steel valve in a steam turbine fell off after 6 years in service.Stellite6 alloy was deposited on COSTE steel by electrode arc welding,and the failure reason of Stellite6 coating was studied.The results show that COSTE steel has diluted Stellite 6 alloy during surfacing,and the Fe element gathers near the interface of the Stellite6.During service,the Fe element diffuses extensively from the steel substrate to the Stellite6 coating.Excessive Fe content promotes theα-Co(Cr,Fe,W)solid solution in Stellite6 coating to generate brittle BCCα'-FeCo(Cr,W)phase andσ-CrCo(Fe,W)tetragonal phase.The brittle phase structure eventually leads to the failure of Stellite6 coating under long-time working load and thermal stress action.

关 键 词：Stellite6合金 铁扩散 相转变 显微硬度 

分 类 号：TG174.44[金属学及工艺—金属表面处理] TG441.7[金属学及工艺—金属学]