FAILURE ANALYSIS ON MOTORCYCLE CHAIN WHEEL BOLT AND THE IMPROVING MEASURE

Motorcycle chain wheel is important bolt which join Rear wheel and Chain wheel.It must endure great shearing force and radial stress. The analysis of binding bolt were made by means of SEM, optical microscope and chemical analysis. It is shown that the failure of binding bolt caused by brittle fracture. This paper introduced characters and main reason of the defect, such as extending acid wash time. In addtion fold defect, insufficiency of getting rid of Hydrogen, etc. also influence binding bolt quality. In the same time, the conditions causing brittle fracture and the measure to prevent the crack are also discussed.