Plain fatigue and fretting fatigue behavior of hot-rolled steel sheet after cold spinning

Fretting fatigue may occur on the surface of a wheel disc in the contact area of the mounting face of the wheel to the flange. Plain fatigue and fretting fatigue tests of specimens sectioned from actual fabricated wheels after cold spinning were carried out to understand the influence of surface condition after plastic forming on fretting fatigue behavior. Cold spinning increased surface hardness with low level of compressive residual stress, which is a factor for enhancing fatigue strength. However, cold spinning also increased surface roughness and induced surface defects, which significantly degraded plain fatigue strength. In fretting fatigue, the stress concentration at the fretting contact edge was a more significant factor in controlling fretting fatigue behavior than the surface defects. Therefore, fretting fatigue strengths for grinding, milling and cold spinning surfaces of fretting fatigue specimens almost coincided regardless of surface condition.