Experimental Investigation of Roughness Transfer with Skin-Pass Rolling to High Strength Low Alloy (HSLA) Material

In skin-pass rolling, which is the last stage of cold rolling, the roughness is transferred to the surface of sheet materials by means of specially roughened rolls. Sheet material becomes ready for use at the end of the skin-pass rolling process. In terms of dyeing and shaping capability of the material, the surface is desired to have an optimum roughness profile. In this study, HC420LA grade sheet material was used from HSLA (high strength low alloy) steels, which has been recently used in the automobile industry to reduce the weight of vehicles and fuel consumption due to its high strength feature. From the rolling parameters, the effects of reduction ratio, rolling speed, roll roughness, and lubricating condition on roughness transfer were investigated experimentally. It was observed that roughness transfer ratio increases as the reduction ratio increases. Roughness transfer ratio decreased as the roll roughness increased and when lubricant was used. In addition, there was no observed effect of the increase in the rolling speed on the roughness transfer ratio. With the use of lubricant, a more homogeneous roughness distribution was obtained compared to the dry conditions. It was concluded that increasing the reduction ratio, roll roughness, and rolling speed disrupted the homogeneous roughness distribution.