An experimental investigation into roughness transfer in skin-pass rolling of steel strips

Abstract

The surface of sheet metals should have a certain level of roughness in terms of forming and dyeing quality. Surface roughness is mainly introduced to the material by rolling with rough rolls, which is called temper rolling. The roughness of a roll is transferred to the material, depending on the rolling parameters. A 2-high rolling setup equipped with a load-cell measuring the rolling force, which can roll at different speeds and reduction ratios, was used to observe the change in the amount of roughness transfer. Surface roughness values of specimens were measured after tests, their average and standard deviation values were calculated, and 3-D field scanning images were investigated. The results obtained were evaluated in terms of rolling parameters and roughness transfer. It was concluded that each parameter that increased the rolling force also increased the roughness transfer. It was seen that rolling force, and thus roughness transfer, was higher in the tests conducted at high speeds and high reduction ratios with thinner materials. Lubricated roughening tests indicated that the introduction of roughness on material surface decreased due to lubrication. Moreover, a more homogeneous roughness distribution was obtained in lubricated rolling compared to dry rolling. It was observed that the roughness at small reduction ratios was obtained within a narrower range.