某石化厂高压聚乙烯装置1976年投产使用至今,其吐出配管上出现了裂纹。为找出裂纹产生的原因,对该管产生裂纹的部分进行了失效分析,根据裂纹断口特征确定了裂纹的性质为疲劳裂纹,检验了材料的金相组织、硬度和外壁的腐蚀情况,并通过应力分析找出裂纹扩展的动力,得出了裂纹产生的原因为腐蚀疲劳,并提出了相应的改进措施。 A petrochemical plant high-pressure polyethylene plant put into operation in 1976 so far, the spit on the pipe appeared cracks. In order to find out the cause of the crack, the failure analysis was made on the cracked part of the tube. According to the fracture characteristics of the crack, the crack was determined as the fatigue crack, and the microstructure, hardness and corrosion of the outer wall of the tube were examined. Stress analysis to find out the driving force of crack propagation, the cause of the crack is found to be corrosion fatigue, and the corresponding improvement measures are put forward.