电厂汽轮机主汽门螺栓断裂原因  

Reasons for bolt breakage of the main steam valve of power plant steam turbine

作　　者：杨东旭 崔倩倩 尹志轶 孙振西[4] 李敞 许子豪 YANG Dongxu;CUI Qianqian;YIN Zhiyi;SUN Zhenxi;LI Chang;XU Zihao(Shandong Electric Power Industry Boiler and Pressure Vessel Inspection Center Co.,Ltd.,Ji’nan 250002,China;Shandong Institute for Porduct Quality Inspection,Ji’nan 250102,China;Shandong Huaneng Weihai Power Generation Plant,Weihai 264200,China;Shandong Antai Chemical Pressur Vessel Inspection Center Co.,Ltd.,Ji’nan 250000,China)

机构地区：[1]山东电力工业锅炉压力容器检验中心有限公司,济南250002 [2]山东省产品质量检验研究院,济南250102 [3]华能威海发电有限责任公司,威海264200 [4]山东省安泰化工压力容器检验中心有限公司,济南250000

出　　处：《理化检验（物理分册）》2024年第3期66-70,共5页Physical Testing and Chemical Analysis(Part A:Physical Testing)

基　　金：山东电力工业锅炉压力容器检验中心有限公司科研项目(GJYF22-04)。

摘　　要：某电厂主汽门用GH6783合金紧固螺栓在回装热紧过程中发生断裂。采用宏观观察、化学成分分析、扫描电镜及能谱分析、金相检验、力学性能测试等方法对螺栓断裂的原因进行分析。结果表明:螺栓由中心孔内表面向外扩展断裂,呈晶界氧化脆性断裂特征;β时效处理不当使晶界处未生成网状较窄且连续的β-NiAl相,导致晶界的抗氧化性较差;在螺栓紧固过程中,外加应力高于晶界强度,最终导致螺栓断裂。The fastening bolt of GH6783 alloy for the main steam valve of a certain power plant broke during the reinstallation and hot tightening process.The causes of bolt fracture were analyzed using methods such as macroscopic observation,chemical composition analysis,scanning electron microscopy and energy spectrum analysis,metallographic examination and mechanical property testing.The results show that the bolt extended outward from the inner surface of the central hole,showing the characteristics of grain boundary oxidation brittle fracture.Improperβ-aging treatment resulted in the absence of a narrow and continuous network at the grain boundariesβ-NiAl phase,led to poor oxidation resistance of grain boundaries.During the bolt tightening process,the applied stress was higher than the grain boundary strength,ultimately led to bolt fracture.

关 键 词：GH6783合金螺栓 晶界氧化脆性断裂 β时效 显微组织 合金贫化区 

分 类 号：TB31[一般工业技术—材料科学与工程] TK264.9[动力工程及工程热物理—动力机械及工程]