Martensitic stainless steel and method of manufacturing same
AssigneePosco
InventorsByoungjun Song, Sanghoon Kim, Gyujin Jo
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Abstract
A martensitic stainless steel cast according to one embodiment of the present invention may be a martensitic stainless steel cast comprising in weight %: C: 0.40% to 0.55%, N: 0.01% to 0.10%, Si: 0.2% to 0.6%, Mn: 0.4% to 0.9%, Cr: 13.6% to 15.0%, Ni: 0.01% to 0.30%, and the remainder including Fe and inevitable impurities, wherein the area fraction of primary carbides having an area of 2000 μm2 or more in the central segregation zone is 2.5% or less.
Claims16
A martensitic stainless steel cast, comprising, in wt %, 0.40 to 0.55% of C, 0.01 to 0.10% of N, 0.2 to 0.6% of Si, 0.4 to 0.9% of Mn, 13.6 to 15.0% of Cr, 0.01 to 0.30% of Ni, and the remainder including Fe and inevitable impurities,
- wherein an area fraction of primary carbides having an area of 2000 μm2 or more in the central segregation zone is 2.5% or less.
A martensitic stainless steel comprising, in wt %, 0.40 to 0.55% of C, 0.01 to 0.10% of N, 0.2 to 0.6% of Si, 0.4 to 0.9% of Mn, 13.6 to 15.0% of Cr, 0.01 to 0.30% of Ni, and the remainder including Fe and inevitable impurities,
- wherein the number of primary carbides having a diameter of 3 μm or more is 22 (ea/mm2) or less.
A method of manufacturing a martensitic stainless steel cast, the method comprising:
- reducing a slab comprising, in wt %, 0.40 to 0.55% of C, 0.01 to 0.10% of N, 0.2 to 0.6% of Si, 0.4 to 0.9% of Mn, 13.6 to 15.0% of Cr, 0.01 to 0.30% of Ni, and the remainder including Fe and inevitable impurities, with a reduction ratio of 2 to 4% during continuous casting,
- wherein the area fraction of primary carbides having an area of 2000 μm2 or more in the central segregation zone is 2.5% or less.
A method of manufacturing a martensitic stainless steel, the method comprising:
- reducing a slab comprising, in wt %, 0.40 to 0.55% of C, 0.01 to 0.10% of N, 0.2 to 0.6% of Si, 0.4 to 0.9% of Mn, 13.6 to 15.0% of Cr, 0.01 to 0.30% of Ni, and
- the remainder including Fe and inevitable impurities, with a reduction ratio of 2 to 4% into a cast;
- first reheating the cast;
- first hot rolling the first reheated cast;
- second reheating the first hot-rolled cast;
- second hot rolling the second reheated cast;
- coiling the cast;
- and
- batch annealing the cast,
- wherein the first reheating is performed at 1200 to 1300° C. for 1 to 4 hours,
- the first hot rolling is performed with a reduction ratio of 50 to 60%, and
- the second reheating is performed at 1200 to 1300° C. for 1 to 4 hours.
Dependencies are inferred from the claim text.