1000t/h直流锅炉12Cr1MoV钢导汽管弯头爆破分析

Analysis on the Explosion of a 12Cr1MoV Steam Connecting Pipe Bend in 1000 t/h Once Through Boiler

谏壁发电厂的超高压锅炉12Cr1MoV钢导汽管弯头运行36215小时后发生爆破。通过对管道弯头部位的宏观检查、断口分析和金相显微组织检验等实验鉴定,以及对管壁厚度的强度校核和从理论上对实际运行温度进行了估算。结果表明,钢管显微组织与原始状态相比较,已有了明显的改变,蠕变空洞等微观结构缺陷增多,钢管提前进入老龄状态。造成钢管加速老龄化的主要原因是管壁所处的工作温度长期偏高于正常温度状态所致。实验鉴定和理论计算所得出的管壁温度偏高的结论与现场经常超温的运行记录的情况相一致。

A fracture at the bend of a 12Cr1MoV steam connecting pipe in a 1000 t/h natural circulating boiler was occurred after 36215 hr. operation.Visual inspection, metallographic and microfractographic examination as well as a check on pipe wall strength and theoretical calculation of actual superheated steam temperature were carried out. The results showed that themicrostructure of the pipe, in comparison with original material, has beenchanged significantly. the microstructure defects in the pipe material has increased and the aging process of the pipe acceralated. The main reason of the pipe aging is that the pipe has been operated at elevated temperature over a long period of time. Both the experimental results and theoretical calculation of the pipe temperature are well in agreement with the field operation record.