Risk Assessment of Stress Corrosion Cracking of 42CrMo High Strength Steel Bolts In Seacoast Environment

Modified wedge opening loading (WOL) specimens were tested in seacoast environment to study the stress corrosion cracking (SCC) behavior of 42CrMo steel, which was widely used for manufacturing high-strength bolts. The results showed that the threshold stress intensity factor K_ISCC was 95.5 MPa· √m and the crack propagation rate was 1.35×10^-9 m/s. The mathematic model based on fracture mechanism was applied for calculating the stress intensity factor in the root of the thread grooves. The risk assessment criterion of SCC was established. The results showed that the proposed criterion could effectively evaluate the safety of high-strength bolts. It was found that the risk of SCC was more severe with increasing working load and initial crack depth.