Posco

Se Il Lee

June Soo Park

Hun Ju Lee

Jae Hoon Kim

Hyunwoo Mun

A non-oriented electrical steel sheet according to an embodiment of the present invention includes, in wt %, Si: 1.5% or less, C: 0.01% or less (excluding 0%), Mn: 0.03 to 3%, P: 0.01 to 0.2%, S: 0.001 to 0.02%, Al: 0.01% or less (excluding 0%), N: 0.005% or less (excluding 0%), Cu: 0.02 to 0.3%, 0.0001 to 0.005 wt % of Ca and Mg either alone or in total, 0.001 to 0.2 wt % of Sb and Sn either alone or in total, and a balance of Fe and inevitable impurities.

Non-oriented electrical steel sheet and manufacturing method therefor

A non-oriented electrical steel sheet according to one embodiment of the present invention comprises, by weight, 1.0% to 4.0% of Si, 0.001% to 0.01% of Al, 0.002% to 0.009% of S, 0.01% to 0.3% of Mn, 0.001% to 0.004% of N, 0.004% or less (0% exclusive) of C, 0.003% or less (0% exclusive) of Ti, 0.005% to 0.07% of Cu, 0.05% to 0.2% of either or both of Sn and P, and a balance amount of Fe and impurities.

The non-oriented electrical steel sheet according to one embodiment of the present invention includes: by weight, 2.0% to 4.0% of Si; 0.001% to 2.0% of Al; 0.0005% to 0.009% of S; 0.02% to 1.0% of Mn, 0.0005% to 0.004% of N; 0.004% or less of C (excluding 0%); 0.005% to 0.07% of Cu; 0.0001% to 0.007% of O; individually or in a total amount of 0.05% to 0.2% of Sn or P; and the remainder comprising Fe and impurities; wherein the non-oriented electrical steel sheet is composed of a surface portion to 2 &#x3bc;m from the surface of the steel sheet in the thickness direction and a base portion exceeding 2 &#x3bc;m from the surface of the steel sheet in the thickness direction, and wherein the number of surfides having a diameter of 10 nm to 100 nm is larger than the number of the nitrides having a diameter of 10 nm to 100 nm, in the same area of base portion.

A method for manufacturing a non-oriented electrical steel sheet according to an exemplary embodiment of the present invention includes performing hot rolling on a slab after heating the slab to manufacture a hot rolled sheet; performing hot rolled sheet annealing on the hot rolled sheet; performing cold rolling on a steel sheet on which the hot rolled sheet annealing is completed to manufacture a cold rolled sheet; and performing cold rolled sheet annealing on the cold rolled sheet in which a difference between a cold rolled sheet annealing temperature in the cold rolled sheet annealing and a hot rolled sheet annealing temperature in the hot rolled sheet annealing is 100&#xb0; C. or lower.

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Pohang-si, South Korea

Se Il Lee