某电厂TP347H不锈钢弯管中性面开裂失效分析  

Failure Analysis of TP347H Stainless Steel Elbow Neutral Surface Cracking in a Power Plant

作　　者：闫俊 YAN Jun(Datang Northeast Electric Power Test&Research Institute Co.,Ltd.)

机构地区：[1]大唐东北电力试验研究院有限公司

出　　处：《电站系统工程》2024年第1期61-63,共3页Power System Engineering

摘　　要：通过宏观形貌观察,化学成分分析、力学性能测试、显微组织观察、应力状态分析等测试手段对某电站锅炉屏式再热器TP347H钢弯管中性面开裂原因进行分析。结果表明,弯管长时间高温运行后,晶界析出大量含Cr碳化物,导致晶界贫铬弱化,发生晶间氧化,导致初始裂纹萌生;弯管应力数值分析显示弯管中性面内壁承受拉应力,同时中性面外壁的机械损伤加剧了应力集中作用,致使内壁氧化缺口位置微裂纹萌生后,在拉应力作用下不断由内向外沿晶扩展,直至穿透管壁,导致漏泄。The reasons for the cracking of the neutral surface of the TP347H steel elbow of a boiler panel reheater in a power station are analyzed by means of macroscopic morphology observation,chemical composition analysis,mechanical performance test,microstructure observation,stress state analysis and other test methods.The results show that a large number of Cr-containing carbides precipitated at the grain boundary after long-term high-temperature operation of the elbow,leading to weakening of chromium depletion at the grain boundary,intergranular oxidation,and initial crack initiation.Numerical analysis of the stress of the elbow shows that the inner wall of the neutral surface of the elbow bears tensile stress,and the mechanical damage of the outer wall of the neutral surface aggravates the stress concentration.After the micro cracks in the oxidation notch position of the inner wall are initiated,they continue to move from the inside to the outside under the action of tensile stress.The crystal expands until it penetrates the pipe wall,causing leakage.

关 键 词：再热器管 TP347H钢 弯管中性面 晶间氧化 应力开裂 

分 类 号：TK223.3[动力工程及工程热物理—动力机械及工程]