锅炉碳钢蒸汽管断裂失效原因分析

Analysis of Fracture Failure of Carbon Steel Steam Pipe for Boiler

中高压蒸汽管材料为20g,设计寿命为20~25年,使用10年后发生了断管,现场调查蒸气管存在超温使用现象。通过常温力学性能分析表明蒸气管用料符合技术要求,材质成分分析与金相分析结果表明碳含量偏高及珠光体球化明显,得出碳钢管长期在蠕变温度环境下产生高温蠕变、持久强度极限下降是造成材料低应力脆性断裂的主要原因。

The medium high pressure steam pipe materical is 20 G and its design life is 20-25 years. After 10 years,it breaks in its use. In the field investigation,it is found that the phenomenon of overtemperature exists in it. In the mormal temperature,its material meets its specification. The results of material composition analysis and metallographic analysis indicate that when the carbon content is high,the spherification of pearlite is obvious. It is concluded that the low stress and brittle fracture of the carbon steel tube are mainly caused by the high temperature creep and the drop in its lasting strength limit.