Provided is a grain-oriented electrical steel sheet having better transformer iron loss property than conventional grain-oriented electrical steel sheets. A grain-oriented electrical steel sheet comprises: a steel substrate; a forsterite film on a surface of the steel substrate; and a Cr-depleted layer at a boundary between the steel substrate and the forsterite film, the Cr-depleted layer having a Cr concentration that is 0.70 times to 0.90 times a Cr concentration of the steel substrate.

Provided is a rail that is effective in improving wear resistance and rolling contact fatigue (RCF) resistance. The rail has a metallic structure including a pearlitic structure and a structure other than the pearlitic structure in a surface layer from a surface of a rail head to a depth of at least 0.5 mm, where the pearlitic structure has Vickers hardness of 420 HV or more and 520 HV or less, and the structure other than the pearlitic structure has Vickers hardness of 350 HV or more and 420 HV or less.

A non-oriented electrical steel sheet according to an embodiment of the present invention includes, in wt%, Si: 2.2 to 4.5 %, Mn: 0.5 % or less (excluding 0 %), AI: 0.001 to 0.5 %, Sn: 0.07 to 0.25 %, and N: 0.0010 to 0.0090 %, and the balance of Fe and inevitable impurities.

A surface layer portion existing in an inner direction from a surface of the steel sheet and a central portion existing inside the surface layer portion are included, and the central portion includes N at 0.005 wt% or less, and the surface layer portion further includes N at 0.001 wt% or more compared to the central portion; and the surface layer portion has an average grain size of 60 .Math.m or less, while the central portion has an average grain size of 70 to 300 .Math.m.

A method for manufacturing a grain-oriented electrical steel sheet according to an embodiment of the present invention comprises the steps of: hot-rolling a slab to prepare a hot-rolled sheet, the slab containing, in wt %, 2.0 to 6.0% of Si, 0.04 to 0.12% of Mn, 0.001 to 0.022% of N, 0.027 to 0.060% of C, 0.01 to 0.08% of Nb, 0.01% or less of Ti, and the balance of Fe and other inevitable impurities; cold-rolling the hot-rolled sheet to prepare a cold-rolled sheet; and subjecting the primarily recrystallization-annealed cold-rolled sheet to secondary recrystallization annealing.

A method for manufacturing a grain-oriented electrical steel sheet according to an embodiment of the present invention comprises the steps of: hot-rolling a slab to prepare a hot-rolled sheet, the slab containing, in wt %, 2.0 to 6.0% of Si, 0.04 to 0.12% of Mn, 0.001 to 0.022% of N, 0.027 to 0.060% of C, 0.01 to 0.08% of Nb, 0.01% or less of Ti, and the balance of Fe and other inevitable impurities; cold-rolling the hot-rolled sheet to prepare a cold-rolled sheet; and subjecting the primarily recrystallization-annealed cold-rolled sheet to secondary recrystallization annealing.

The present invention provides a steel sheet having excellent wear resistance and composite corrosion resistance, and a method of manufacturing same. According to one example of the present invention, a corrosion-resistant steel sheet having excellent wear resistance and composite corrosion resistance comprises, in wt %: 0.04-0.10% of carbon (C); 0.10% or less (excluding 0%) of silicon (Si); 0.20-0.35% of copper (Cu); 0.1-0.2% of nickel (Ni); 0.05-0.15% of antimony (Sb); 0.07-0.22% of tin (Sn); 0.05-0.15% of titanium (Ti); 0.01% or less (excluding 0%) of sulfur (S); 0.005% or less (excluding 0%) of nitrogen (N); 0.05-0.15% of molybdenum (Mo); and the balance of iron (Fe) and inevitable impurities, and satisfies formula 1 and formula 2 below.

[Ni]/[Cu]≥0.5   [Formula 1]

48×([Ti]/48−[S]/32−[N]/14)≥0.04   [Formula 2]

Here, in formula 1 and formula 2, [Ni], [Cu], [Ti], [S], and [N] represent Ni, Cu, Ti, S, and N content (wt %) in the steel sheet, respectively.

The present invention provides a steel sheet having excellent wear resistance and composite corrosion resistance, and a method of manufacturing same. According to one example of the present invention, a corrosion-resistant steel sheet having excellent wear resistance and composite corrosion resistance comprises, in wt %: 0.04-0.10% of carbon (C); 0.10% or less (excluding 0%) of silicon (Si); 0.20-0.35% of copper (Cu); 0.1-0.2% of nickel (Ni); 0.05-0.15% of antimony (Sb); 0.07-0.22% of tin (Sn); 0.05-0.15% of titanium (Ti); 0.01% or less (excluding 0%) of sulfur (S); 0.005% or less (excluding 0%) of nitrogen (N); 0.05-0.15% of molybdenum (Mo); and the balance of iron (Fe) and inevitable impurities, and satisfies formula 1 and formula 2 below.

[Ni]/[Cu]≥0.5   [Formula 1]

48×([Ti]/48−[S]/32−[N]/14)≥0.04   [Formula 2]

Here, in formula 1 and formula 2, [Ni], [Cu], [Ti], [S], and [N] represent Ni, Cu, Ti, S, and N content (wt %) in the steel sheet, respectively.

Provided is a steel sheet and a method for manufacturing same, the steel sheet, which can be used for automobile parts and the like, having superb bendability, and excellent balance of strength and ductility and of strength and hole expansion ratio. The steel sheet includes: by wt %, C: 0.25 to 0.75%, Si: 4.0% or less, Mn: 0.9 to 5.0%, Al: 5.0% or less, P: 0.15% or less, S: 0.03% or less, N: 0.03% or less, a balance of Fe, and unavoidable impurities; and as microstructures, ferrite which is a soft structure, and tempered martensite, bainite, and retained austenite which are hard structures.

Provided is a steel sheet and a method for manufacturing same, the steel sheet which can be used for automobile parts and the like, having excellent bending workability, and excellent balance of strength and ductility and of strength and hole expansibility.

Provided is a steel sheet which can be used for automobile parts and the like, and relates to a steel sheet having a superior balance of strength and ductility and strength and hole expansion ratio and superior bending formability, and a method for manufacturing same.