| abstract |
The present invention prevents agglomerates of inclusions in molten steel and finely disperses the inclusions in the steel sheet, thereby reliably preventing surface scratches and cracks during press molding, and also promotes recrystallized grain growth during continuous annealing and high r value. Since the ultra-low carbon steel sheet and the manufacturing method thereof which show (r value ≥ 2.0) and elongation (total elongation ≥ 50%) are provided, the mass% is 0.0003% ≤ C ≤ 0.003%, Si ≤ 0.01%, Mn ≤ 0.1% , P ≦ 0.02%, S ≦ 0.01%, 0.0005% ≦ N ≦ 0.0025%, 0.01% ≦ acid value Ti ≦ 0.07%, acid value Al ≦ 0.003%, further 0.002% ≦ La + Ce + Nd ≦ 0.02%, residual amount Ultra-low carbon having excellent surface properties, formability and processability, wherein the steel sheet is formed of additional iron and unavoidable impurities, and the steel sheet contains at least cerium oxysulfide, lanthanum oxysulfide, and neodymium oxysulfide. A steel sheet. |