2009 Volume 49 Issue 6 Pages 881-889
The surface roughness of carbon steel sheets is controlled by dull roll surface imprinting by temper rolling. In most cases, temper rolling is performed using a lubricant or under a dry condition. However, the oil film of the lubricant and its lubricating ability have not been clarified. In this study, the effect of a lubricant on surface imprinting by temper rolling was investigated under the following three lubrication states: a dry condition (no lubricant), with a water-soluble lubricant and with a mineral oil. Temper rolling experiments for as-annealed low-carbon steel strips and as-annealed high-carbon steel strips were conducted in the reduction range of 1 to 3%, using the 4-high rolling mill. A shot-dull roll and an electric-discharged dull roll were employed as work rolls. The surface texture of temper rolled strips was observed directly, and surface textures in terms of the mean roughness (Ra), three-dimensional texture, cross-sectional profile, material ratio curve and probability density in order to compare the effect of the lubrication states. As a result, for high-carbon steel, the use of the water-soluble lubricant leads to better surface imprinting than the dry condition and the use of the mineral oil. The use of the mineral oil results in the least surface imprinting. For the low-carbon steel, the use of the water-soluble lubricant and the dry condition lead to better surface imprinting than the use of the mineral oil.