METHOD OF PICKLING HOT-ROLLED COILED STEEL STRIPS Russian patent published in 2003 - IPC

FIELD: rolling; possibly pickling of hot-rolled coiled steel strips in mineral acid solutions. SUBSTANCE: method incorporates steps of pickling metal in hydrochloric acid solution in line of continuous pickling unit, rinsing of pickled strip surface with water, drying by hot air, reeling pickled hot-rolled strips into coils, acid drainage from sections of pickling bath during shutdown of continuous pickling unit; in so doing during forced shutdown of pickling unit, upon completion of shutdown, strip reversal is carried out in continuous pickling unit in "rearward" direction by length being larger or equal to length of rinsing bath and unit drying area; simultaneously with strip reversal in line of continuous pickling unit rinsing water is supplied on strip at the beginning of pickling bath; squeezing portion of strip, reversed "rearward" from pickling bath, of the remains of rinsing water, acid solution and ferric salts takes place; and upon completion of "rearward" reversal of strip in line of continuous pickling unit and prior to movement of line in "forward" direction a pause is to be maintained within not more than 30 sec. This method allows cost coefficient to be reduced by 10% to 44% not only for pickling, but for the whole production stage; elimination of unnecessary division of coils and deterioration of quality of surface of finished cold-rolled strips with respect to surface and longitudinal difference in thickness. EFFECT: reduced cost coefficient and enhanced quality. 1 dwg, 2 tbl, 1 ex