MANUFACTURE OF BASE MATERIAL OF COLD-ROLLED STEEL SHEET FOR CONTINUOUS ANNEALING

• Main Authors: KATSUMATA MASAAKI, TSUKATANI ICHIRO, YAKUSHIJI TERUTOSHI
• Format: Patent
• Language: English
• Published: 19.02.1988
• Subjects: ALLOYS; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; TREATMENT OF ALLOYS OR NON-FERROUS METALS

PURPOSE:To obtain a base material of cold-rolled steel sheet for continuous annealing excellent in deep drawability, and cooling a molten steel in which respective amounts of C, Mn, S, Al, O, N, and Ti and/or Nb for solidification and then by subjecting, after controlled heating if necessary, the resulting slab to controlled cooling at a specified temp. CONSTITUTION:A molten metal which consists of, by weight, 0.002-0.015% C, 0.05-0.4% Mn, <0.01% Si, 0.01% S, 0.01-0.07% solAl, <0.01% O, <0.006% N, 0.02-0.15% solTi and/or 0.02-0.15% solNb, and the balance Fe with inevitable impurities and in which solTi, Nb/(C+N) atomic concentration is regulated to >0.15% is cooled to undergo solidification. This slab is maintained so that its temp. is kept at >550 deg.C. The slab is hot-rolled after heated to 1,050-1,180 deg.C at >=8 deg.C/min heating rate when the slab temp. is <1,050 deg.C and without heating when the slab temp. is >=1,050 deg.C and without heating when the slab temp. is >=1,050 deg.C. The above hot rolling is finished at a temp. of the Ar3 transformation point or above and then winding is carried out at <=650 deg.C.