2017 Volume 58 Issue 672 Pages 41-46
The typical sliding conditions at the fracture-risk positions in press forming of automotive parts were identified by FE analysis and laboratory-scale sliding tests. The investigated sliding conditions fall into three categories：the inflow sections of a steel sheet （group A）, the punch shoulders in drawing （group B）, and the stretch sections （group C） . The frictional properties of group A and group B could be evaluated by measurement of the dynamic coefficient of friction in the flat sliding tests under a high contact pressure and at low sliding speed in each group area. The frictional properties of group C could be evaluated by the static coefficient of friction, which is measured as the primary peak in a coefficient of friction – stroke curve under the specific sliding test conditions （contact pressure：7MPa, sliding speed：10mm/min, tool length：10mm） .