TP347H不锈钢末级再热器弯管爆漏原因分析  

Explosive Leakage Cause Analysis of TP347H Stainless Steel Final Reheater Elbow

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作  者:郑建军 樊子铭 张涛[1] 孙云飞 ZHENG Jianjun;FAN Ziming;ZHANG Tao;SUN Yunfei

机构地区:[1]内蒙古电力科学研究院,呼和浩特010020

出  处:《青海电力》2021年第4期61-64,68,共5页Qinghai Electric Power

摘  要:某电厂锅炉运行24000 h后,末级再热器弯管发生开裂泄漏失效。利用宏观形貌观察、化学成分分析、金相显微组织分析、断口形貌观察、拉伸试验等方法,对末级再热器弯管的爆漏原因进行了分析。结果表明:末级再热器弯管未进行有效的固溶处理,抗晶间腐蚀能力较弱;同时,锅炉运行温度刚好处于奥氏体不锈钢的敏化温度区间,长期运行使得材料的抗腐蚀能力进一步下降;此外,运行过程中弯管处存在较大的应力集中,最终在晶间腐蚀严重部位造成钢管发生应力型晶间腐蚀开裂导致的泄漏。建议首先排查同类型钢管有无开裂现象,发现问题及时处理;其次,应按照标准要求对同类型TP347H不锈钢弯管进行固溶处理,以避免再次发生类似开裂泄漏失效。The final reheater elbows were found to be cracked and failed after 24000 h operation of a power plant boiler.In this paper,the causes of explosion and leakage of the final reheater elbow are analyzed by means of macroscopic morphology observation,chemical composition analysis,metallographic microstructure analysis,fracture morphology observation and tensile test.The results show that the final reheater has not been effectively treated by solid solution,and its resistance to intergranular corrosion is weak;Besides,the boiler operating temperature is just in the sensitization temperature range of austenitic stainless steel,and the long-term operation is further reduced the corrosion resistance of the material;In addition,there is a large stress concentration at the elbow during operation,and finally the leakage caused by stress-induced intergranular corrosion cracking is triggered in the parts with serious intergranular corrosion.It is firstly suggested to check whether the same type of steel pipe is cracked and deal with the problems in time;Secondly,the same type of TP347H stainless steel elbow shall be subject to solution treatment according to the standard requirements to avoid similar cracking and leakage failure again.

关 键 词:末级再热器弯管 开裂 泄漏 晶间腐蚀 

分 类 号:TM621.25[电气工程—电力系统及自动化] TK225[动力工程及工程热物理—动力机械及工程]

 

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