Cold-rolled steel sheet with excellent weldability and method for manufacturing same
AssigneePosco
InventorJaiik Kim
Life of this patent
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Abstract
The present invention relates to a cold-rolled steel sheet and a method for manufacturing same. A cold-rolled steel sheet according to one embodiment comprises, in weight %, 0.01~0.05% of carbon (C), 0.6~1.2% of manganese (Mn), 0.05% or less (excluding 0%) of silicon (Si), 0.0005~0.01% of phosphorus (P), 0.008% or less (excluding 0%) of sulfur(S), 0.0005~0.015% of aluminum (AI), 0.0005~0.003% of nitrogen (N), 0.1~0.4% of tungsten (W), 1.0~2.0% of chromium (Cr), 0.05~0.15% of zirconium (Zr), and the remainder of Fe and inevitable impurities, wherein the yield strength of a welding member may be 500 MPa or more.
Claims11
A cold-rolled steel sheet comprising:
- in weight %, 0.01~0.05% of carbon (C), 0.6~1.2% of manganese (Mn), 0.05% or less (excluding 0%) of silicon (Si), 0.0005~0.01% of phosphorus (P), 0.008% or less (excluding 0%) of sulfur(S), 0.0005~0.015% of aluminum (Al), 0.0005~0.003% of nitrogen (N), 0.1~0.4% of tungsten (W), 1.0~2.0% of chromium (Cr), 0.05~0.15% of zirconium (Zr), and the remainder of Fe and inevitable impurities,
- wherein the yield strength of a welding member is 500 MPa or more.
A method for manufacturing a cold-rolled steel sheet comprising:
- heating a steel slab including, in weight %, 0.01~0.05% of carbon (C), 0.6~1.2% of manganese (Mn), 0.05% or less (excluding 0%) of silicon (Si), 0.0005~0.01% of phosphorus (P), 0.008% or less (excluding 0%) of sulfur(S), 0.0005~0.015% of aluminum (AI), 0.0005~0.003% of nitrogen (N), 0.1~0.4% of tungsten (W), 1.0~2.0% of chromium (Cr), 0.05~0.15% of zirconium (Zr), and the remainder of Fe and inevitable impurities;
- hot-rolling the heated slab at a finish rolling temperature of 820 to 880° C.;
- winding the hot-rolled steel sheet at 580 to 700° C.;
- cold-rolling the wound hot-rolled steel sheet to 50 to 90%;
- and
- annealing the cold-rolled steel sheet in a temperature range of 700 to 850° C.
Dependencies are inferred from the claim text.