Failure Analysis of Stainless Steel Bolt

Two stainless steel bolts of the motor components assembly fractured after serving for eight hours.The fracture feature and cause of the bolt were analyzed by appearance observation, micro and macro observation on fracture surfaces, metallographic examination, hardness testing.The results show that the fracture mode of the bolts is hydrogen brittleness fracture.The high intensity and biggish assembly stress led to the hydrogen brittleness fracture of the bolt.Meanwhile, there is a lack of dehydrogenation disposal after inactivating technology in the entire technological process.It is proposed that the intensity should be in the range of criterion requirements, and the dehydrogenation disposal should be disposed after passivation technology according to standard.What's more, the assembly stress should be controlled strictly to avoid early stage damage of bolt.