700 MW亚临界锅炉三级过热器TP347HFG钢失效分析  

Failure Analysis of Superheater Tube Steel TP347HFG for a 700 MW Subcritical Boiler

作　　者：李文华[1] 柯安鹏 LI Wen-hua;KE An-peng(Zhuhai Power Station of Guangdong Yudean Group Co.,Ltd.,Guangdong Zhuahai 519060,China)

机构地区：[1]广东省粤电集团有限公司珠海发电厂

出　　处：《失效分析与预防》2019年第6期415-419,共5页Failure Analysis and Prevention

摘　　要：针对亚临界锅炉三级过热器SA213−TP347HFG奥氏体不锈钢管材发生爆管,通过对其进行硬度检查、金相组织观察、SEM电镜扫描和能谱分析,找出导致爆管的原因。结果表明:奥氏体晶粒明显长大,晶界有碳化物Cr23C6析出导致晶界贫铬,抗腐蚀性能下降;长期高温甚至超温工况下的晶间腐蚀导致了SA213−TP347HFG三级过热器的爆管。本研究对掌握该批材料服役情况具有重大的借鉴意义,并提出预防类似事故的建议。A SA213-TP347H steel superheater tube of a subcritical boiler burst.Metallographic observation,hardness testing,SEM observation and energy spectrum analysis were conducted to find out the failure cause.The results show that the grain size of the austenite coarsened apparently,and Cr23C6 precipitates in the grain boundaries led to chromium depletion in the grain boundaries.As a result,the corrosion resistance degraded.Finally,the tube burst because of intergranular corrosion under the long-time high temperature or sometimes even overheating.The present work is of great significance to figuring out the service situation of the material.Some suggestions were put forward to prevent such accidents.

关 键 词：爆管 晶界腐蚀 碳化物 SA213−TP347HFG 

分 类 号：TK223.32[动力工程及工程热物理—动力机械及工程] TG142.25[一般工业技术—材料科学与工程]