Clean cold-rolled steel strip prodn. - by weak lubricant emulsion injection at last mill stand

摘要

Clean cold rolled strip is produced by (i) injecting a rolling lubricant emulsion of low concn. at high ressure onto both faces of the stri at the last roling mill stand to remove spots of oil or metal dust from the strip surfaces, (ii) charging the cold rolled strip to a box annealing surface; (iii) mixing steam with the furnace atmos. comprising mainly nitrogen and hydrogen; and (iv) controlling the dew point of the furnace atmos. to within a predetermined temp. range, pref. -1 deg. C. Clean steel strip is roduced in a simple and economical manner, without requiing ceaning instalations, and strip prodn. yields can be increased by about .2% due to the improvement in surface quality.