超超临界机组T92钢高温受热面管爆管原因分析

某电厂的后屏过热器T92钢管段发生爆管。通过宏观检验、化学成分分析、硬度检验、拉伸性能测试、金相检验以及相关计算分析了爆管的原因。结果表明：管段发生短时过热后，其显微组织为Acl-Ac3相变产物，失去了原典型的回火板条马氏体组织特征，材料强度大幅度降低，从而使得强度不足以抵抗管子的使用应力而发生爆管。另外，通过检验获得了不同状态下的组织与性能的对应关系，有利于长期运行中的金属监督检验。

Reason Analysis on Bursting Tube of High Temperature Boiler Tube of T92 Steel in Ultra Supercritical Unit

The platen superheater tube failures of T92 steel has bursted in a ultra supercritical power plants.The bursting reason was analyzed by means of macroscopical inspection,chemical composition analysis,hardness testing,tensile strength testing,metallographic examination and so on.Results showed that the microstructure of the tube which didn’t maintenance the typical lath martensite,the phase transformation at AC1~AC3 after short-term overheated.The strength decreased rapid distinctly,therefore the strength was not enough to endure the stress,finally the tube bursted.On the other hand,the relationship between the different microstructure and mechanical property was achieved by test in order to supervise for metal in thermal power plants for long term operation.