锅炉屏式过热器夹持管开裂原因分析及其优化措施探索

Cause Analysis and Optimization Measures for Cracking of Clamping Tube of Boiler Platen Superheater

文中主要对锅炉屏式过热器夹持管开裂原因进行了分析研究。通过宏观、力学试验、金相显微组织观察、光谱分析、硬度检测对材质为TP347的夹持管进行宏观、微观分析,用显微镜对金相组织形貌进行了分析。试验结果发现,夹持管母材内壁的硬度值高于外壁,金相组织中存在脆性相的形变马氏体,且奥氏体组织内存在滑移线,脆性的马氏体相在应力作用下产生裂纹,在锅炉运行中的热应力和振动产生的交变应力共同作用下,裂纹不断发展最终发生断裂。同时提出了对夹持管结构形式进行优化改造的措施。

This paper mainly analyzes and studies the cracking causes of the clamping tube of boiler platen superheater.The clamping tube made of TP347 was analyzed macroscopically and microscopically by macro,mechanical test,metallographic microstructure observation,spectral analysis and hardness test,and the metallographic microstructure was analyzed by microscope.The test results show that the hardness value of the inner wall of the base metal of the clamping tube is higher than that of the outer wall,there is deformation martensite of brittle phase in the metallographic structure,and there is slip line in the austenitic structure.The brittle martensite phase produces cracks under the action of stress.Under the combined action of thermal stress and alternating stress generated by vibration during boiler operation,the cracks continue to develop and finally fracture.At the same time,the measures to optimize the structural form of clamping pipe are put forward.