摘要
对某600 MW超临界机组高温过热器弯头在运行不到1 000 h发生开裂现象进行了外观检查、显微分析,同时对冷弯成型工艺过程进行数值模拟。研究表明:亚稳态不锈钢TP347H冷弯成形时内弧应变量超过ASME规范要求,产生马氏体相变,形成点蚀源,在残余应力与高温运行时热应力的共同作用下引起的内弧面开裂是弯头寿命降低的主要原因。
A macrostructure examination and scanning electron microscopy analysis was made on the failure of the high-temperature super-heater elbow which was operated less than 1 000 h.The process of pipe cold bending was simulated.It shows that： the forming strain at the intrados of metastable state stainless TP347H steel,while bending exceeded ASME standard,causes martensitic phase transformation.It was the pitting source of the tube.The intergranular fracture which was caused by both the residual stress and the heat stress acted on the coarse precipitate at the intrados is the main reason of the drop of the elbow life.
出处
《盐城工学院学报（自然科学版）》
CAS
2012年第1期29-32,共4页
Journal of Yancheng Institute of Technology:Natural Science Edition
基金
福建省自然科学基金资助项目(2009J01259)
关键词
过热器弯头
内弧面
冷弯成形
数值模拟
残余应力
super-heater elbow
intrados
cold bending
numerical simulation
residual tensile stress
