高強度鋼板の摺動摩擦特性に及ぼす面圧・速度・摺動距離の影響

抄録

The friction behavior of ultrahigh-tensile-strength steel sheets such as a 980MPa-grade tensile strength sheet has been investigated to improve the formability of steel sheets. The results of sliding friction tests showed that the friction coefficients of high-tensile-strength steel sheets decrease as the contact pressure between tools and sheets and sliding velocity increases. The results of sliding friction tests with a long bar tool showed that friction coefficients increase proportionally to sliding length. It is clarified that the effects of contact pressure, sliding velocity and sliding length on the frictional behavior of high-tensile-strength steel sheets are the same as those on the frictional behavior of mild steels. The friction coefficients are closely associated with the flat area ratio on sheet surfaces, which results from the deformation of a sheet surface convex portion. Finally, the friction model for FE forming analysis is proposed.