A frictional study of uncoated EBT steel sheets in a bending under tension friction test

A factorial design was used to investigate the frictional response of different uncoated EBT surface topographies. The test included three different topographies (Sibetex® materials), two lubricants, two contact pressures, and two sliding speeds. The steel sheet strips were subjected to a Bending Under Tension (BUT) friction test. Our findings indicate that the most significant factor, affecting friction, is lubricant viscosity, followed by sliding speed, contact pressure, and surface topography. For measurement of the sheet surface topography, a 3D stylus-instrument was used and the ball-filtering technique was applied. The surface topography was measured in the contact zone on the test samples. The results show that the surface topography is a significant factor, influencing friction in mixed lubrication. The larger the number of isolated lubricant pockets, the smaller is the friction coefficient. These isolated pockets identified here are located in the topmost area and are imprints from the rolls before the first textured rolls.