1. Luoyang Ship Material Research Institute， Luoyang 471023， China；2. Henan Key Laboratory of Technology
and Application of Structural Materials for Ships and Marine Equipments，Luoyang 471023， China
Abstract： The material of joint for one connector was 35# steel with heat treatment condition of asnormalized condition. The joint fractured suddenly after a period of use. The fractured joint was analyzed by optical metallographic microscope and scanning electron microscope, and the fracture mode and cause were found out. The fracture mode of the joint was fatigue. There were two reasons for the fatigue fracture of the joint: (1) 15# steel joint was used instead of 35# steel joint, which reduced the fatigue strength of the joint; (2) the sharp angle in joint design produced a greater stress concentration, which became the origin of fatigue fracture, resulting in the decrease of fatigue strength.
2021, Vol. 39 
