Abstract: 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 ?m 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 (?)F, and separated, in the thickness direction of the flange, from the outer face in the thickness direction of the flange by (¼)t2, when the width direction length of the flange is F and the thickness of the flange is t2; a yield strength or 0.

Abstract: 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 ?m 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 (?)F, and separated, in the thickness direction of the flange, from the outer face in the thickness direction of the flange by (¼)t2, when the width direction length of the flange is F and the thickness of the flange is t2; a yield strength or 0.

Abstract: In a rolled H-shape steel, at a (?)F position from an outer edge surface in a flange width-direction a microstructure at a depth of 100 ?m from an outer surface in the flange thickness-direction and a microstructure at a depth of (½)tf from the outer surface in the flange thickness-direction contain 95% or more of ferrite and pearlite and 5% or less of a residual structure by area ratio, the difference in Vickers hardness therebetween is 50 Hv or less, the yield strength is 385 to 505 N/mm2, the tensile strength is 550 to 670 N/mm2, the yield ratio is 0.80 or less, an elongation is 16.0% or more, the V-notch Charpy absorbed energy at 0° C. is 70 J or more, the height is 700 to 1000 mm, the flange width is 200 to 400 mm, the flange thickness is 22 to 40 mm, and the web thickness is 16 mm or more.

Abstract: Provided is a steel H-shape for low temperature service including a predetermined chemical composition. A CEV obtained by CEV=C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15 is 0.40 or less. A sum of an area ratio of one or both of ferrite and bainite at a 1/4 position from an outer side across a thickness of a flange and a 1/6 position from an outer side across a flange width is 90% or more, and an area ratio of a hard phase is 10% or less. An effective grain size is 20.0 ?m or less, and a grain size of the hard phase is 10.0 ?m or less. 30 pieces/mm2 or more Ti oxides having an equivalent circle diameter ranging from 0.01 to 3.0 ?m are included. The thickness of the flange ranges from 12 to 50 mm.

Abstract: This H section includes, as a chemical composition, C, Si, Mn, Nb, V, Ti, and N; in which the H section includes, as a metallographic structure, ferrite of 60 area % to less than 100 area %, an average grain size of this ferrite is 1 ?m to 30 ?m, a thickness of a flange is 20 mm to 140 mm, tensile yield stress is 385 MPa to 530 MPa, and Charpy absorbed energy at ?20° C. is 100 J or more.

Abstract: An H-section steel has a predetermined chemical composition, in which a Mg-containing oxide having an equivalent circle diameter of 0.005 ?m to 0.5 ?m is contained at a total number density of 100 pieces/mm2 to 5000 pieces/mm2, a thickness of a flange is 100 mm to 150 mm, at a strength evaluation portion which is at a ? position from a surface of the flange in a length direction and at a ¼ position from the surface in a thickness direction, a fraction of bainite in a steel structure is 80% or more, and the average prior austenite grain size is 70 ?m or more, and at a toughness evaluation portion which is at a ½ position from the surface of the flange in the length direction and at a ¾ position from the surface of the flange in the thickness direction, the average prior austenite grain size in a steel structure is 200 ?m or less.

Abstract: Provided is a steel H-shape for low temperature service including a predetermined chemical composition. A CEV obtained by CEV=C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15 is 0.40 or less. A sum of an area ratio of one or both of ferrite and bainite at a 1/4 position from an outer side across a thickness of a flange and a 1/6 position from an outer side across a flange width is 90% or more, and an area ratio of a hard phase is 10% or less. An effective grain size is 20.0 ?m or less, and a grain size of the hard phase is 10.0 ?m or less. 30 pieces/mm2 or more Ti oxides having an equivalent circle diameter ranging from 0.01 to 3.0 ?m are included. The thickness of the flange ranges from 12 to 50 mm.

Abstract: In a steel sheet pile according to the present invention, a carbon equivalent CEN is 0.260 to 0.500, a structure includes a ferrite, a pearlite, a Widmanstätten ferrite, and a precipitate, the precipitate is one or both of Nb carbonitride and V carbonitride, a total number density of the precipitate is 0.10 to 0.30 pieces/?m2, a total area ratio of the ferrite and the pearlite is 70% or more, an area ratio of the Widmanstätten ferrite is 1% or more, an average grain size of the ferrite and the pearlite is 10 to 80 ?m, and a yield strength is 460 MPa or more.

Abstract: An H-section steel has a predetermined chemical composition in which Ti oxides having a grain size of 0.01 ?m to 3.0 ?m are included at a density of 30 pieces/mm2 or more, a thickness of a flange is 100 mm to 150 mm, an area fraction of bainite at a ? position from a surface of the flange in a length direction and at a ¼ position from the surface thereof in a thickness direction is 80% or more, a yield strength or 0.2% proof stress is 450 MPa or more, and a tensile strength is 550 MPa or more, a Charpy absorbed energy at 21° C. at a ½ position from the surface of the flange in the length direction and at a ¾ position from the surface thereof in the thickness direction is 100 J or more, and an average austenite grain size is 50 ?m to 200 ?m.

Abstract: This H-beam steel has a composition including C, Si, Mn, Cu, Ni, V, Al, Ti, B, N, and O, and further including at least one of Mo and Nb, in which Ceq obtained in Equation 1 described below falls in a range of 0.37 to 0.50, the thickness of a flange falls in a range of 100 to 150 mm, and the area fraction of bainite at a depth of one quarter of the thickness of the flange from the external surface of the flange is 60% or more. Ceq=C+Mn/6+(Mo+V)/5+(Ni+Cu)/15??Equation 1, where C, Mn, Mo, V, Ni, and Cu represent the amount of each element contained.

Abstract: An H-section steel has a predetermined chemical composition in which a thickness of a flange is 100 mm to 150 mm, at a strength evaluation position an area fraction of bainite in a steel structure is 80% or more, yield strength or 0.2% proof strength is 450 MPa or more, tensile strength is 550 MPa or more and 680 MPa or less, at a toughness evaluation position an average austenite grain size in the steel structure is 150 ?m or less, and (Mg, Mn)S having a particle size of 0.005 ?m to 0.5 ?m is included at a density of 1.0×105 pieces/mm2 to 1.0×107 pieces/mm2.

Abstract: This H-beam steel contains, in mass %, C, Si, Mn, Al, Ti, N, O, Nb, and B. The H-beam steel has composition in which the amount of Nb and the amount of B satisfy, in mass %, 0.070?Nb+125B?0.155, and has a metal structure in which, in a microstructure, an area fraction of bainite is not less than 70%, a total of an area fraction of pearlite and an area fraction of cementite is not more than 15%, and the remainder is at least one of ferrite and island martensite. The effective crystalline-grain size of the bainite is not more than 40 ?m, and the thickness of a flange falls in a range of 12 to 40 mm.

Abstract: An H-section steel has a predetermined chemical composition, in which a Mg-containing oxide having an equivalent circle diameter of 0.005 ?m to 0.5 ?m is contained at a total number density of 100 pieces/mm2 to 5000 pieces/mm2, a thickness of a flange is 100 mm to 150 mm, at a strength evaluation portion which is at a ? position from a surface of the flange in a length direction and at a ¼ position from the surface in a thickness direction, a fraction of bainite in a steel structure is 80% or more, and the average prior austenite grain size is 70 ?m or more, and at a toughness evaluation portion which is at a ½ position from the surface of the flange in the length direction and at a ¾ position from the surface of the flange in the thickness direction, the average prior austenite grain size in a steel structure is 200 ?m or less.

Abstract: An H-section steel has a predetermined chemical composition in which Ti oxides having a grain size of 0.01 ?m to 3.0 ?m are included at a density of 30 pieces/mm2 or more, a thickness of a flange is 100 mm to 150 mm, an area fraction of bainite at a ? position from a surface of the flange in a length direction and at a ¼ position from the surface thereof in a thickness direction is 80% or more, a yield strength or 0.2% proof stress is 450 MPa or more, and a tensile strength is 550 MPa or more, a Charpy absorbed energy at 21° C. at a ½ position from the surface of the flange in the length direction and at a ¾ position from the surface thereof in the thickness direction is 100 J or more, and an average austenite grain size is 50 ?m to 200 ?m.

Abstract: There is provided an H-section steel in which a number density of oxide particles having an equivalent circle diameter of 0.005 ?m to 2.0 ?m per unit area is 100 pieces/mm2 to 5000 pieces/mm2, the oxide particles includes Ca, Al, and O as a composition, the amount of Ca is 5% or more, the amount of Al is 5% or more, and a total amount of Ca and Al is 50% or more by mass ratio excluding O in the oxide particles, a thickness of the flange is 100 mm to 150 mm, a bainite fraction in a metallographic structure of the flange is 80% or more at a strength evaluation position, and an average prior austenite grain size in the metallographic structure of the flange is 200 ?m or less at a toughness evaluation position.

Abstract: A welding joint comprises a pair of steel materials, and a welding metal that is formed with a high-energy density beam at a butt welding portion between the pair of steel materials, wherein a transformation starting temperature Ms that is calculated by a following formula: Ms(° C.)=371?353C?22Si?24.3Mn?7.7Cu?17.3Ni?17.7Cr?25.8Mo, using a composition of mass % of the welding metal is 250° C. or less.

Abstract: An H-section steel has a predetermined chemical composition in which a thickness of a flange is 100 mm to 150 mm, at a strength evaluation position an area fraction of bainite in a steel structure is 80% or more, yield strength or 0.2% proof strength is 450 MPa or more, tensile strength is 550 MPa or more and 680 MPa or less, at a toughness evaluation position an average austenite grain size in the steel structure is 150 ?m or less, and (Mg, Mn)S having a particle size of 0.005 ?m to 0.5 ?m is included at a density of 1.0×105 pieces/mm2 to 1.0×107 pieces/mm2.

Abstract: An H-section steel has a predetermined chemical composition, an Nb content and a B content satisfy Nb+125×B?0.075%, a thickness of a flange is 12 mm to 40 mm, and in a thickness center portion and ¼ flange width portion of the flange, a metallographic structure of a cross-section perpendicular to a rolling direction contains pearlite having a distribution density of 3.2×10?3 units/?m2 or lower and the remainder is formed of ferrite and bainite.

Abstract: In a steel sheet pile according to the present invention, a carbon equivalent CEN is 0.260 to 0.500, a structure includes a ferrite, a pearlite, a Widmanstätten ferrite, and a precipitate, the precipitate is one or both of Nb carbonitride and V carbonitride, a total number density of the precipitate is 0.10 to 0.30 pieces/?m2, a total area ratio of the ferrite and the pearlite is 70% or more, an area ratio of the Widmanstätten ferrite is 1% or more, an average grain size of the ferrite and the pearlite is 10 to 80 ?m, and a yield strength is 460 MPa or more.

Abstract: There is provided an H-section steel in which a number density of oxide particles having an equivalent circle diameter of 0.005 ?m to 2.0 ?m per unit area is 100 pieces/mm2 to 5000 pieces/mm2, the oxide particles includes Ca, Al, and O as a composition, the amount of Ca is 5% or more, the amount of Al is 5% or more, and a total amount of Ca and Al is 50% or more by mass ratio excluding O in the oxide particles, a thickness of the flange is 100 mm to 150 mm, a bainite fraction in a metallographic structure of the flange is 80% or more at a strength evaluation position, and an average prior austesiite grain size in the metallographic structure of the flange is 200 ?m or less at a toughness evaluation position.