METHOD FOR CONTROLLING COLD-ROLLED STEEL DEFECT OF TITANIUM-CONTAINING ULTRA-LOW CARBON STEEL

摘要

A method for controlling a cold-rolled steel defect of a titanium-containing ultra-low carbon steel. The titanium-containing ultra-low carbon steel has the following components in percentage by weight: C ≤ 0.005%, Si ≤ 0.05%, Mn 0.05-0.3%, Al 0.02-0.1%, Ti 0.008-0.05%, P ≤ 0.05%, S ≤ 0.02%, N ≤ 0.003%, T.O 0.0010-40%, and the balance of Fe and inevitable impurities, in which Al content is greater than or equal to Ti content. After RH vacuum decarburization is finished, Ti is added first, and the addition amount of Ti is controlled at the lower limit value of the finished product value; Al is then added, the addition amount is controlled at the median of the finished product value, and the circulation time of liquid steel is greater than or equal to 3 min; other alloying elements are added and/or the steel melt components are adjusted according to the specification of the finished product, and the circulation time of the steel melt is greater than or equal to 2 min; rare earth metals Ce and La are added, in which the addition amount is REM/T.O = 0.6 - 3.0 by mass ratio, the mass unit of rare earth REM is kg, and the unit of the total oxygen T.O in the steel) is ppm; and the circulation time of the steel melt is greater than or equal to 2 min, and oxide Ce2O3Al2O3 or La2O3Al2O3 is produced in the steel melt.