This steel sheet has a predetermined chemical composition, in which a steel structure of an inside of the steel sheet contains, by volume fraction, soft ferrite: 0% to 30%, retained austenite: 3% to 40%, fresh martensite: 0% to 30%, a sum of pearlite and cementite: 0% to 10%, and a remainder includes hard ferrite, in the inside of the steel sheet, a number proportion of the retained austenite having an aspect ratio of 2.0 or more in the total retained austenite is 50% or more, a soft layer having a thickness of 1 to 100 μm from a surface in a sheet thickness direction is present, in ferrite contained in the soft layer, a volume fraction of grains having an aspect ratio of less than 3.0 is 50% or more, the volume fraction of retained austenite in the soft layer is less than 50% of the volume fraction of the retained austenite of the inside of the steel sheet, and a peak of an emission intensity at a wavelength indicating Si appears in a range of more than 0.2 μm and 5.0 μm or less from the surface.

In an H-section steel, which has a predetermined chemical composition, a thickness of the flange is from 25 to 140 mm; an average crystal grain diameter is 38 μm or less and the area fraction of a martensite-austenite constituent is 1.2% or less, in a plane orthogonal to the width direction of the flange, centering on a measurement position 7 that is a position separated, in the width direction of the flange, from the end face in the width direction of the flange by (⅙)F, and separated, in the thickness direction of the flange, from the outer face in the thickness direction of the flange by (¼)t.sub.2, when the width direction length of the flange is F and the thickness of the flange is t.sub.2; a yield strength or 0.2% proof stress is 385 MPa or more and a tensile strength is 490 MPa or more, in the rolling direction of the flange, when measured with respect to the entire thickness in the thickness direction of the flange at a position separated in the width direction of the flange from the end face in the width direction of the flange by (⅙)F; and the absorbed energy in a Charpy test at the measurement position 7 at −20° C. is 200 J or more.

A grain-oriented electrical steel sheet according to an embodiment of the prevent invention comprises: Si: 1.0% to 7.0%, C: 0.005% or less (excluding 0%), P: 0.0010 to 0.1%, Sn: 0.005 to 0.2%, S: 0.0005 to 0.020%, Se: 0.0005 to 0.020% and B: 0.0001 to 0.01% by weight, and the remainder comprising Fe and other inevitable impurities.

An oriented electrical steel sheet according to an embodiment of the present invention includes, in a unit of wt %, Si at 1.0 wt % to 5.0 wt %, C at 0.005 wt % or less (excluding 0 wt %), Mn at 0.001 wt % to 0.1 wt %, Cu at 0.001 wt % to 0.1 wt %, S at 0.001 wt % to 0.020 wt %, Se at 0.001 wt % to 0.050 wt %, Al at 0.0005 wt % to 0.010 wt %, N at 0.0005 wt % to 0.005 wt %, and the remainder of Fe and inevitable impurities.

The oriented electrical steel sheet according to the embodiment of the present invention satisfies Equation 1.

16(10[Mn]+[Cu])/([S]+[Se])+(0.02[Al])/[N]20 [Equation 1]

(In Equation 1, [Mn], [Cu], [S], [Se], [Al], and [N] represent contents (wt %) of Mn, Cu, S, Se, Al, and N, respectively.)

Disclosed are a ferritic stainless steel capable of inhibiting high temperature oxidation through generation of an effective oxide scale, and manufacturing method thereof. The ferritic stainless steel excellent in oxidation resistance at high temperature according to an embodiment of the present disclosure includes, in percent (%) by weight of the entire composition, Cr: 10 to 30%, Si: 0.2 to 1.0%, Mn: 0.1 to 2.0%, W: 0.3 to 2.5%, Ti: 0.001 to 0.15%, Al: 0.001 to 0.1%, the remainder of iron (Fe) and other inevitable impurities, and satisfies a following equation (1).

W/(Ti+Al)10(1)

Disclosed is a ferritic stainless steel with improved strength, workability, and corrosion resistance, which may be applied to various industrial fields, such as washing machines, refrigerators, and all kinds of electric home appliances. An embodiment of the disclosed ferritic stainless steel comprises, in percent by weight (wt %), 0.0005 to 0.02% of C, 0.005 to 0.02% of N, 0.7 to 1.0% of Si, 16.0 to 17.0% of Cr, 0.05 to 0.3% of Ti, and the balance being Fe and inevitable impurities, wherein the ferritic stainless steel has a value of Formula (1) below satisfying 21 to 25, a tensile strength of 470 MPa or more, and an elongation of 27% or more.

7*Si+Cr(1)

In Formula (1), Si and Cr represent the contents (wt %) of the respective elements.

The present invention provides a steel material for a seismic damper, and a manufacturing method for same. The steel material comprises, in wt %, at most 0.006% of C, at most 0.05% of Si, at most 0.3% of Mn, at most 0.02% of P, at most 0.01% of S, 0.005 to 0.05% of Al, at most 0.005% of N, 48/14[N] to 0.05% of Ti (here, [N] is the nitrogen content in wt %), 0.04 to 0.15% of Nb, and the remainder in Fe and other unavoidable impurities, and has a ferrite single structure, and has a ferrite grain average particle size of 150 to 500 m in a region of a surface layer part, corresponding to 30% of the total thickness from the surface thereof.

A method for producing a metal product, wherein in a strand casting system, liquid metal is output as a slab from a mold vertically downward in a conveying direction, is guided along a strand guide, and is deflected into the horizontal, wherein the slab is heated in a furnace or inductively downstream of the stand casting system.

A steel material for a low yield ratio, high-strength steel pipe having excellent low-temperature toughness according to an aspect of the present invention comprises, by weight %, 0.03-0.065% of C, 0.05-0.3% of Si, 1.7-2.2% of Mn, 0.01-0.04% of Al, 0.005-0.025% of Ti, 0.008% or less of N, 0.08-0.12% of Nb, 0.02% or less of P, 0.002% or less of S, 0.05-0.3% of Cr, 0.4-0.9% of Ni, 0.3-0.5% of Mo, 0.05-0.3% of Cu, 0.0005-0.006% of Ca, 0.001-0.04% of V, and the balance of Fe and inevitable impurities, wherein a number of deposits having an average diameter of 20 nm or less per unit area in a cross section of the steel material may be 6.5*10.sup.9/mm.sup.2 or greater.

A manufacturing method of a utility ferritic stainless steel with excellent hot workability is disclosed. The manufacturing method of a ferritic stainless steel according to an embodiment of the present disclosure includes: manufacturing a slab including, in percent (%) by weight of the entire composition, C: 0.005 to 0.020%, N: 0.005 to 0.020%, Si: 0.5 to 0.8%, Mn: 0.5 to 1.5%, Cr: 11.0 to 12.5%, Ni: 0.2 to 0.6%, P: 0.035% or less (excluding 0), S: 0.01% or less (excluding 0), the remainder of iron (Fe) and other inevitable impurities; and hot rolling the slab after heating the slab, and the heating of the slab is performed in a temperature range of 1200 to 1250 C. so that the fraction of -ferrite phase in the internal structure of the slab is 80 to 95%.