Abstract
A roll surface texture is imprinted on a carbon steel sheet in temper rolling. It is important to reduce the roll microwear; since the roll surface causes the microwear, the value of the surface imprinting could not be provided. In most cases, dry condition or a lubricant was applied as lubrication states in temper rolling. However, the influence of lubricant with respect to the roll microwear has not been clarified. In this work, roll microwear has been evaluated in three lubrication states by the 4Hi rolling mill. Temper rolling experiments for as-annealed low carbon steel strips and as-annealed high carbon steel strips have been conducted in the range of 1 to 3% in reduction. Non lubricant (dry condition), water soluble lubricant and mineral oil were utilized as lubrication states. A shot dull roll (SDR) and an electric-discharged dull roll (EDR) were employed. Surface textures of the rolls have been observed directly. Surface textures in terms of mean surface roughness (Ra), three dimensional textures, cross section profiles and material ratio curves were applied to compare the dull rolls microwear. As a result, roll microwear is caused during 80 m rolling length making contact with the back up roll and steel strips; this because stable afterwards. The electric-discharged dull roll shows larger roll microwear than the shot dull roll with dry lubrication. The water soluble lubricant and the mineral oil both decrease the roll microwear of the electric-discharged dull roll.
