Cause Analysis on Cracking of Double Self-sealing High Hydraulic Pipe Joint

Crack occurred in the assembly of double self-sealing high hydraulic pipe joint for a cleaning machine. The causes of joint cracking were analyzed by means of chemical composition analysis, metallographic test and mechanical property test. The results show that joint cracking was mainly due to improper annealing treatment of the joint material after cold drawing forming which resulted in a large number of slip lines formed in the process of cold deformation in the structure, resulting in higher strength and hardness of the material, the brittleness of the material increased and the plasticity decreased, thus joint cracks occurred due to stress in the assembly process.