Ferritic stainless steel having improved corrosion resistance, and method for manufacturing same
AssigneePosco
InventorsJin-suk Kim, Junghyun Kong, Mun-soo Lee
Life of this patent
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Abstract
Disclosed are a ferritic stainless steel having improved corrosion resistance and a method for manufacturing same. The ferritic stainless steel according to an embodiment of the present disclosure includes, in percent by weight (wt%), 0.001 to 0.05% of C, 0.001 to 0.05% of N, 0.1 to 1.0% of Si, 0.1 to 1.0% of Mn, 12.0 to 22.0% of Cr, 0.01 to 1.0% of Ti, and 0.01 to 1.0% of Nb, with the balance being Fe and inevitable impurities, wherein an area ratio of microdefects is 2% or less, and a sulfur (S) content in a surface film within 5 mm from the surface is 10% or less.
Claims15
A ferritic stainless steel having improved corrosion resistance comprising, in percent by weight (wt%), 0.001 to 0.05% of C, 0.001 to 0.05% of N, 0.1 to 1.0% of Si, 0.1 to 1.0% of Mn, 12.0 to 22.0% of Cr, 0.01 to 1.0% of Ti, and 0.01 to 1.0% of Nb, with the balance being Fe and inevitable impurities,
- wherein an area ratio of microdefects is 2% or less, and
- a sulfur (S) content in a surface film within 5 mm from the surface is 10% or less.
A method for manufacturing a ferritic stainless steel having improved corrosion resistance, the method comprising:
- hot rolling a slab comprising, in percent by weight (wt%), 0.001 to 0.05% of C, 0.001 to 0.05% of N, 0.1 to 1.0% of Si, 0.1 to 1.0% of Mn, 12.0 to 22.0% of Cr, 0.01 to 1.0% of Ti, and 0.01 to 1.0% of Nb, with the balance being Fe and inevitable impurities and hot annealing the hot-rolled steel sheet;
- cold rolling and cold annealing the hot-rolled, annealed steel sheet twice or more by controlling a roll diameter to 70 mm or less;
- degreasing the cold-rolled, annealed steel sheet for 60 seconds to 120 seconds;
- and
- bright annealing the cold-rolled steel sheet,
- wherein surface polishing treatment is introduced after hot annealing or after primary cold rolling.
Dependencies are inferred from the claim text.