Effects of Plastic Strain on Surface Roughness and Coefficient of Friction in Tension-Bending Test

In order to make investigation into the tribological behaviors at the interface between tool and workpiece in the die corner of deep drawing, a tension-bending type test was used. A new tension-bending type test in which constant back tensions were applied and the deformation of specimen was plastic was developed. The workpiece used was an aluminum sheet with a smooth surface. The tests were carried out at a constant speed under various back tensions using a lubricant. The drawing force was measured during test and after tests the surface roughness of specimen was measured. In the lower average contact pressure, the surface roughening was predominant and the coefficient of friction was constant. On the other hand, in the higher average contact pressure, the flattening of surface asperities is predominant and the coefficient of friction decreased with increasing average contact pressure.