| 摘要 |
FIELD: manufacture of thin sheet from low-carbon steel. ^ SUBSTANCE: method involves producing thin sheet from low-carbon steel having superior surface characteristics, formability and workability, containing, wt%: 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-soluble Ti<=0.7, acid-soluble Al<=0.003, 0.002<=La+Ce+Nd<=0.02, iron the balance and unavoidable admixtures. Steel sheet contains at least cerium oxysulfide, lanthanum oxysulfide and neodymium oxysulfide. Method involves heating steel blank; providing hot rolling of blank and winding rolled blank to thereby produce hot-rolled steel strip; providing cold rolling of said strip at reduction extent of 70% or more, followed by continuous recrystallization annealing at temperature of 600-900 C. During continuous annealing process, inclusions are finely dispersed in steel sheet to thereby promote growth of recrystallized grains with radius r equal to or than 2.0 and total percentage of elongation equal to or more than 50%. ^ EFFECT: increased efficiency in preventing coalescence and growth of inclusions in steel, surface defects and cracks in the process of stamping. ^ 9 cl, 2 tbl, 1 ex |
