Abstract:

The 60Si2Mn contact sheet of bridge contact in the circuit breaker experiences abnormal fracture under the static state.A detailed analysis is conducted on the microstructure and fracture morphology of the contact sheet using methods such as the macroscopic examination,the metallographic analysis, and the fracture analysis.A finite element model is established to simulate and analyze the stress situation of the contact sheet in using.The results show that the microstructure of the contact film is normal.The fracture morphology is mainly brittle fracture.The maximum stress value at the notch of the contact sheet is 1 818 MPa.Through the finite element analysis,the contact sheet with no notches and decreasing the length of the inner teeth by 4 mm is recommended to reduce the overall stress of the contact sheet.

Key words: bridge contact, contact sheet, failure analysis, hydrogen embrittlement