600MW超超临界机组锅炉三级过热器爆管分析

The Failure Analysis of Burst Superheater Tube in 600 MW Ultra-Supercritical Power Plant

S30432作为典型的奥氏体耐热钢材料广泛应用于超(超)临界电站锅炉的过热器再热器,对某600MW超超临界机组锅炉采用S30432材料的三级过热器爆管进行了失效分析。为确认过热器S30432材料长时服役下的失效原因和典型特征,将试样划分不同部位,采用宏观形貌检查、金相检测、扫描电镜(SEM)、X射线衍射(XRD)、化学和力学性能检测和强度校核等方法开展相关试验研究,并结合爆管位置和锅炉运行工况进行分析。试验及分析结果表明:该三级过热器管所用S30432材料材质满足标准要求.爆口原因为管子长时过热导致的蠕变失效.长时过热可能是由于管内存在异物造成堵塞或流动异常造成。

As a typical austenitic steel material,S30432 is widely used in the superheater Reheater of ultra supercritical power plant boiler.In this paper,the failure analysis of three-stage superheater tube explosion of a 600 MW unit boiler using S30432 material is carried out.In order to confirm the failure causes and typical characteristics of superheater S30432 material under long-term service,this paper divides the samples into different parts,carries out relevant experimental research by means of macro morphology inspection,metallographic inspection,scanning electron microscope(SEM),X-ray diffraction(XRD),chemical and mechanical property inspection and strength verification,and analyzes them in combination with the position of tube explosion and boiler operating conditions.The test and analysis results show that the material of S30432 used in the three-stage superheater tube meets the standard requirements.The cause of burst is the creep failure caused by long-term overheating of the tube.The long-term overheating may be caused by blockage or abnormal flow caused by foreign matters in the tube.