POSCO Holdings Inc.
HOT-ROLLED COATED STEEL SHEET WITH EXCELLENT WORKABILITY AND MANUFACTURING METHOD THEREFOR

Abstract:

Provided is a hot-rolled coated steel sheet having a yield point elongation of less than 4% and a manufacturing method for the same. The hot-rolled steel sheet comprises, by weight, 0.03 to 0.06% of carbon (C), 0.5 to 1.5% of manganese (Mn), 0.01 to 0.25% of silicon (Si), 0.01 to 0.05% of aluminum (Al), 0.001 to 0.02% of phosphorus (P), 0.006% or less of sulfur (S), 0.0001 to 0.02% of titanium (Ti), 0.0001 to 0.03% of niobium (Nb), 0.001 to 0.005% of nitrogen (N), and a balance of iron (Fe) and inevitable impurities, wherein the Ti, Al and N satisfy the following relationship 1, and the Nb, C and N satisfy the following relationship 2: 0.03.ltoreq.(wt % Ti).times.(wt % Al).times.(wt % N).times.10.sup.6.ltoreq.0.20 (1), and 22.ltoreq.(mol % Nb)/{(mol % C).times.(mol % N)}.ltoreq.1826 (2).