Abhay K. Jha

Failure of cadmium plated maraging steel tension bolt

Abstract Cadmium electroplated (EP) high strength steel fasteners are widely used for assembling threaded joints as cadmium gives lubrication and provides excellent corrosion resistance. However, in-house-failure case histories revealed that in some cases delayed failure of cadmium EP high strength steel fasteners occurred. Recently, one such premature failure of a cadmium EP 18 Ni 1800 MPa maraging steel tension bolt occurred at a sustained stress of about 40% of the ultimate tensile stress (UTS), after 11,500 h. For their successful functional application, cadmium EP fasteners require proper and adequate baking treatment after electroplating. This paper highlights details of analysis carried out on the failed bolt to find out the reason for the failure, using standard metallographic and NDT techniques. Remedial measures to minimise, if not totally prevent, such failure are also discussed.