Non-oriented electrical steel sheet, and method for manufacturing same
Disclosed are a non-oriented electrical steel sheet and a method for manufacturing same, wherein the texture of the electrical steel sheet is optimized after cold rolling by controlling the temperature and atmosphere of decarburization annealing and final annealing, and thus excellent iron loss can be obtained even at low temperatures. In addition, disclosed are a non-oriented electrical steel sheet and a method for manufacturing same, wherein processes, from the processing of the electrical steel sheet into motor component to a final heat-treatment, are improved to enhance the strength of the texture aligned in the direction of easy magnetization and thereby improve the magnetic characteristics of the steel sheet.
1 . A non-oriented electrical steel sheet comprising:
carbon (C): in a range of 0.02 to 0.05 wt %,
silicon (Si): in a range of 1.0 to 3.5 wt %,
aluminum (Al): in a range of 0.2 to 0.6 wt %,
manganese (Mn): in a range of 0.02 to 0.20 wt %,
phosphorus (P): in a range of 0.11 to 0.14 wt %,
sulfur (S): in a range of more than 0 and not greater than 0.01 wt %,
copper (Cu): in a range of more than 0 and not greater than 0.03 wt %,
nickel (Ni): in a range of more than 0 and not greater than 0.03 wt %,
chromium (Cr): in a range of more than 0 and not greater than 0.05 wt %, and
a remainder of iron (Fe) and unavoidable impurities,
wherein the electrical steel sheet has an iron loss W15/50 in a range of 1.70 to 1.90 W/kg, a magnetic flux density B50 in a range of 1.65 to 1.80 T, a tensile strength in a range of 400 to 560 N/mm 2 , and a hardness in a range of 200 to 270 HV, and
wherein the electrical steel sheet has a microstructure in which a crystallographic orientation intensity of a (100) plane is higher than a crystallographic orientation intensity of a (111) plane, and P and S are concentrated at a surface portion of the electrical steel sheet.
2 . A non-oriented electrical steel sheet comprising:
carbon (C): in a range of 0.02 to 0.05 wt %,
silicon (Si): in a range of 1.0 to 3.5 wt %,
aluminum (Al): in a range of 0.2 to 0.6 wt %,
manganese (Mn): in a range of 0.02 to 0.20 wt %,
phosphorus (P): in a range of 0.13 to 0.15 wt %,
sulfur (S): in a range of more than 0 and not greater than 0.01 wt %,
copper (Cu): in a range of more than 0 and not greater than 0.03 wt %,
nickel (Ni): in a range of more than 0 and not greater than 0.03 wt %,
chromium (Cr): in a range of more than 0 and not greater than 0.05 wt %, and
a remainder of Fe and unavoidable impurities,
wherein the electrical steel sheet has an iron loss W15/50 in a range of 1.56 to 1.84 W/kg, a magnetic flux density B50 in a range of 1.65 to 1.80 T, and a hardness in a range of 255 to 264 HV, and a tensile strength in a range of 350 to 540 N/mm 2 , and
wherein the electrical steel sheet has a microstructure in which a crystallographic orientation intensity of a (100) plane is higher than a crystallographic orientation intensity of a (111) plane, and P and S are concentrated at a surface portion of the electrical steel sheet.
3 . The non-oriented electrical steel sheet of claim 1 , wherein the electrical steel sheet has a thickness in a range of 0.05 to 0.50 mm.
4 . The non-oriented electrical steel sheet of claim 2 , wherein the electrical steel sheet has a thickness in a range of 0.05 to 0.50 mm.
5 . A method for manufacturing a non-oriented electrical steel sheet, the method comprising:
reheating and hot rolling a steel slab, the steel slab including:
carbon (C): in a range of 0.02 to 0.05 wt %,
silicon (Si): in a range of 1.0 to 3.5 wt %,
aluminum (Al): in a range of 0.2 to 0.6 wt %,
manganese (Mn): in a range of 0.02 to 0.20 wt %,
phosphorus (P): in a range of 0.11 to 0.14 wt %,
sulfur (S): in a range of more than 0 and not greater than 0.01 wt %,
copper (Cu): in a range of more than 0 and not greater than 0.03 wt %,
nickel (Ni): in a range of more than 0 and not greater than 0.03 wt %,
chromium (Cr): in a range of more than 0 and not greater than 0.05 wt, and
a remainder of iron (Fe) and unavoidable impurities;
performing a hot rolling annealing heat-treatment on the hot-rolled steel sheet and pickling the steel sheet;
cold rolling the pickled steel sheet;
performing a decarburization annealing heat-treatment on the cold-rolled steel sheet at a temperature in a range of 780 to 920° C.; and
performing a final annealing heat-treatment on the decarburization annealing heat-treated steel sheet at a temperature in a range of 980 to 1,020° C.,
wherein the electrical steel sheet has an iron loss W15/50 in a range of 1.70 to 1.90 W/kg and a magnetic flux density in a range of 1.65 to 1.80 T, and a tensile strength in a range of 400 to 560 N/mm 2 and a hardness in a range of 200 to 270 HV, and
wherein the electrical steel sheet has a microstructure in which a crystallographic orientation intensity of a (100) plane is higher than a crystallographic orientation intensity of a (111) plane, and P and S are concentrated at a surface portion of the electrical steel sheet.
6 . A method for manufacturing a non-oriented electrical steel sheet, the method comprising:
reheating and hot rolling a steel slab, the steel slab including:
carbon (C): in a range of 0.02 to 0.05 wt %,
silicon (Si): in a range of 1.0 to 3.5 wt %,
aluminum (Al): in a range of 0.2 to 0.6 wt %,
manganese (Mn): in a range of 0.02 to 0.20 wt %,
phosphorus (P): in a range of 0.13 to 0.15 wt %,
sulfur (S): in a range of more than 0 and not greater than 0.01 wt %,
copper (Cu): in a range of more than 0 and not greater than 0.03 wt %,
nickel (Ni): in a range of more than 0 and not greater than 0.03 wt %,
chromium (Cr): in a range of more than 0 and not greater than 0.05 wt %, and
a remainder of iron (Fe) and unavoidable impurities;
performing a hot rolling annealing heat-treatment on the hot-rolled steel sheet and pickling the steel sheet;
cold rolling the pickled steel sheet;
performing a recrystallization heat-treatment on the cold-rolled steel sheet at a temperature in a range of 700 to 900° C.;
performing an insulation coating on the recrystallization heat-treated steel sheet and then processing the steel sheet; and
performing a final heat-treatment on the processed steel sheet at a temperature in a range of 900 to 1,100° C.,
wherein the electrical steel sheet has an iron loss W15/50 in a range of 1.56 to 1.84 W/kg, a magnetic flux density B50 in a range of 1.65 to 1.80 T, a hardness in a range of 255 to 264 HV, and a tensile strength in a range of 350 to 540 N/mm 2 , and
wherein the electrical steel sheet has a microstructure in which a crystallographic orientation intensity of a (100) plane is higher than a crystallographic orientation intensity of a (111) plane, and P and S are concentrated at a surface portion of the electrical steel sheet.
7 . The method of claim 5 , wherein after the cold rolling of the pickled steel sheet, the cold-rolled steel sheet has a thickness in a range of 0.05 to 0.50 mm.
8 . The method of claim 5 , wherein the decarburization annealing heat-treatment is performed for a duration in a range of 1 to 60 minutes in a hydrogen (H 2 ) gas atmosphere at a temperature in a range of 780 to 820° C.
9 . The method of claim 5 , wherein the final annealing heat-treatment is performed for a duration in a range of 1 to 30 minutes in an argon (Ar) gas atmosphere.
10 . The method of claim 6 , wherein the cold-rolled steel sheet has a thickness in a range of 0.05 to 0.50 mm.
11 . The method of claim 6 , wherein the recrystallization heat-treatment is performed for a duration in a range of 1 to 60 minutes at a temperature in a range of 750 to 850° C.
12 . The method of claim 6 , wherein the final heat-treatment is performed for a duration in a range of 1 to 30 minutes.