Failure Analysis on a Pinion of the Jacking System of a Jack-up Platform

Component analysis, metallographic examination and hardness test were performed respectively for a disabled pinion and a brand-new rack of the jacking system of a jack-up platform. The results show that because the superficial heat treatment of the pinion was not uniform, there was no hardened layer near the pitch circle of the pinion. Thus the surface hardness of the disabled pinion was lower than that of the rack, which led to the contact fatigue failure of the pinion near the pitch circle.