Friction of Steel Slabs on a Roller Table under Varying Physical Conditions

Abstract

A knowledge of the coefficient of friction between steel slabs and the surfaces of rollers is important for the design and operation of roller tables in steelworks, and values were determined from acceleration tests on a model roller table. When cold the effective coefficient of friction was greater with a light slab than with a heavy slab, and was greater with low roller speeds than with high roller speeds. The effective coefficient of friction was independent of slab temperature in the range 700–1,100 deg. C. (1,290–2,010 deg. F.), and with hot slabs it was affected less by slab weight and roller speed. When the slip between the rollers and the slab became small, the effective coefficient of friction decreased with cold slabs and increased with hot slabs. The mean value with cold slabs was 0.20 and with hot slabs it was 0.29. Grit-blasting the slab surface increased the value by about 5 per cent and with heavily oxidized slabs the value was about 10 per cent greater. Adding powdered mill scale and water to the rollers increased the value with hot slabs by about 20 per cent but not with cold slabs. Some observations in a steelworks support the results.