316L不锈钢循环水泵内护管断裂原因分析

Analysis on the Fracture Reason of 316L Stainless Steel Inner Protection Barrel of the Circulating Water Pump

针对某燃气-蒸汽联合循环机组循环水泵内护管断裂,通过化学成分分析、金相分析、扫描电镜分析、硬度检验和力学性能试验等技术手段对断裂的内护管进行了分析。结果表明,循环水泵内护管316L不锈钢材质的硬度和延伸率不符合相关标准要求,强度过高,抗疲劳性能差。循环水泵内护管在自身重量和水压反复加载的共同影响下运行时,在导流栅处造成应力集中,形成疲劳源,从而发生了疲劳断裂。

Based on the fractured inner protection barrel of the circulating water pump in a gas-steam combined cycle unit,The fracture reasons were analyzed by chemical composition analysis,metallographic analysis,scanning electron microscope analysis,hardness test and mechanical property test.The experimental results showed that the hardness and elongation of 316L stainless steel material for the inner protection barrel of the circulating water pump didn′t reach the requirements of relevant standards,the strength was too high,and the fatigue resistance was poor.When the inner protection barrel of the circulating water pump ran under the combined influence of its own weight and repeated loading of water pressure,it caused stress concentration at the guide grid,then formed the fatigue source,that occurred fatigue fracture.