Abstract: A suspension arm includes a main body. The main body includes a curved portion curved along a longitudinal direction and has a closed section. The main body includes an inner side wall, an outer side wall, a first side wall, and a second side wall. The inner side wall corresponds to an inner side of a curve of the curved portion. The outer side wall corresponds to an outer side of the curve of the curved portion. A thickness of the inner side wall is larger than a thickness of the outer side wall. In sectional view of the main body perpendicular to the longitudinal direction, each of a length of the first side wall and a length of the second side wall is longer than each of a length of the inner side wall and a length of the outer side wall.

Abstract: Provided is a burring processing method, which is a method for forming a buffing processed portion including a raised portion and a curved portion in a metal component having a pilot hole formed therein, the method being characterized by including: a preforming step of enlarging a diameter of the pilot hole, moving an edge portion of the pilot hole relative to the metal component in a first direction of a thickness direction of the metal component in a first range around the pilot hole of the metal component, and forming the whole first range into a preformed portion raised from the metal component in the first direction; and a main forming step of deforming the preformed portion in a second direction opposite to the first direction, forming a second range on an outer diameter side of the preformed portion to have the same height as the first range in the first direction, and forming part of a third range on an inner diameter side of the preformed portion from the second range to be part of the curved portion

Abstract: A steel sheet for hot stamping includes, as a chemical composition, by mass %: C: 0.060% to 0.120%; Si: 0% to 0.70%; Mn: 1.60% to 3.00%; P: 0.100% or less; S: 0.0100% or less; N: 0.0100% or less; Al: 0.001% to 0.100%; Ti: 0.005% to 0.050%; and B: 0.0005% to 0.0100%. If necessary, the chemical composition contains one or two or more selected from the group consisting of Nb, V, W, Ni, Cu, Mo, Sn, Ca, Mg, and REM and a remainder of Fe and impurities, A microstructure includes 70% or more of upper bainite by area ratio, and a number density of iron carbides having a major axis of 0.01 ?m or more included in the upper bainite is equal to or greater than 4/?m2.

Abstract: A steel sheet has a predetermined chemical composition, in which a metallographic structure in a surface layer region ranging from a surface to a position of 20 ?m from the surface in a sheet thickness direction consists of ferrite and a secondary phase having a volume fraction of 1.0% to 15.0%, the metallographic structure in an internal region ranging from a position of more than 20 ?m from the surface in the sheet thickness direction to a ¼ thickness position from the surface in the sheet thickness direction consists of ferrite and a secondary phase having a volume fraction of 5.0% to 25.0%, the volume fraction of the secondary phase in the surface layer region is less than the volume fraction of the secondary phase in the internal region, and in the surface layer region, the average grain size of the secondary phase is 0.5 ?m to 4.0 ?m.

Abstract: This steel sheet for gas soft nitriding has a predetermined chemical composition and metallographic structure, in which, when a sheet thickness is indicated as t, a sheet width, which is a width in a direction perpendicular to a rolling direction, is indicated as w, and effective grain sizes are measured at seven positions of w/8, w/4, 3w/8, w/2, 5w/8, 3w/4, and 7w/8 in a width direction from an end portion in the width direction at a t/4 depth position from a surface, an average effective grain size, which is an average of the effective grain sizes at the seven positions, is 8.0 to 35.0 ?m, and an effective grain size difference, which is a difference between a maximum value and a minimum value among the effective grain sizes at the seven positions, is 10.0 ?m or less.

Abstract: This hot-dip galvanized steel sheet includes: a steel sheet; a boundary layer provided on the steel sheet; and a hot-dip galvanized layer provided on the boundary layer, in which the steel sheet has a predetermined chemical composition, in a region between a surface of the steel sheet and a depth of 25 ?m from the surface of the steel sheet, an average grain size exceeds 4.0 ?m, in a region between a position of 50 ?m from the surface of the steel sheet and a position of 100 ?m from the surface of the steel sheet, an area ratio of unrecrystallized ferrite is 50% or more, and in the hot-dip galvanized layer, a maximum value of a U concentration is 0.05 mass % or more.

Abstract: This high-strength steel sheet contains predetermined chemical components, in a range from a surface to 1/10 of a sheet thickness in a sheet thickness direction, an average pole density of an orientation group 1 that is an orientation group expressed by ?1=0° to 90°, ?=50° to 60° and ?2=45° in terms of an Euler angle is 1.5 or less, an average pole density of an orientation group 2 that is an orientation group expressed by ?1=450 to 85°, ?=85° to 90° and ?2=45° in terms of the Euler angle is 1.5 or more, an S value that indicates a degree of randomness of surface properties is 7.5 or less, an E value that indicates a degree of concentration of the surface properties is 0.04 or more, and a tensile strength is 590 MPa or more.

Abstract: A burring processing method including increasing a diameter of a prepared hole provided in a metal component and bending a part of the metal component to form a burring processed portion (110) including an upright portion (120) and a curved portion (130), wherein in a cross-section that passes through an axis (cb) of the burring processed portion (110) and is parallel to the axis (cb) of the buffing processed portion (110), a cross-sectional shape of the curved portion (130) on an inner surface of the curved portion consists of a curve, and a length of the curved portion (130) in a direction perpendicular to the axis (cb) of the burring processed portion (110) is at least 1.2 times a height of the curved portion in a direction parallel to the axis (cb) of the burring processed portion (110).

Abstract: An objective of the present disclosure is to provide a front pillar outer that is inexpensive, lightweight and strong. A front pillar outer includes a glass-face-side flange part, a door-side flange part, and a main body part that connects the glass-face-side flange part and the door-side flange part to each other. In a partial area of the door-side flange part in a longitudinal direction thereof, a first plate part that is connected to a side edge of the door-side flange part is folded so that the first plate part is overlaid on the door-side flange part. In a partial area of the glass-face-side flange part in a longitudinal direction thereof, a second plate part that is connected to a side edge of the glass-face-side flange part is folded so that the second plate part is overlaid on the glass-face-side flange part.

Abstract: An objective of the present invention is to provide a front pillar outer that has high strength and high rigidity. In an area in which the first door-side flange part and a second door-side flange part overlap with each other, the first door-side flange part and the second door-side flange part are joined to each other. In an area in which the first glass-face-side flange part and the second glass-face-side flange part overlap with each other, the first glass-face-side flange part and the second glass-face-side flange part are joined to each other.

Abstract: This hot-rolled steel sheet has a predetermined chemical composition, the microstructure includes, by volume percentage, 70% or more of martensite, tempered martensite, and bainite in total and 5% to 20% of residual austenite, in a surface layer region that is a range from a surface to a position at 1/10 of a sheet thickness, a sum of an average pole density of an orientation group consisting of {211}<111> to {111}<112> and a pole density of a crystal orientation of {110}<001> is 6.0 or less, a concentration of solid solution carbon in the residual austenite is 0.5 mass % or more, and a tensile strength is 980 MPa or more.

Abstract: A stiffened panel structure includes a panel-shaped component and a wire. The panel-shaped component has a panel body that curves in such a manner as to be convex outward. The wire has a first end portion and a second end portion. The first end portion is bonded to a first point on the inner surface of the panel body. The second end portion is bonded to a second point on the inner surface of the panel body. The wire is strained between the first point and the second point.

Abstract: This hot-rolled steel sheet has a predetermined chemical composition, a microstructure includes 80% or more of tempered martensite by a volume percentage and a remainder consisting of one or more of ferrite, pearlite, bainite, fresh martensite, and residual austenite, the tempered martensite includes 5×109 pieces/mm3 or more of precipitates containing Ti and having an equivalent circle diameter of 5 nm or less per unit volume, in a surface layer region that is a range from a surface to a 1/10 position of a sheet thickness, a sum of an average pole density of a crystal orientation group consisting of {211}<111> to {111}<112> and a pole density in a crystal orientation of {110}<001> is 6.0 or less, and a tensile strength is 980 MPa or more.

Abstract: A steel sheet includes: a predetermined chemical composition; and a steel structure represented by, in area %, first martensite in which two or more iron carbides each having a circle-equivalent diameter of 2 nm to 500 nm are contained in each lath: 20% to 95%, ferrite: 15% or less, retained austenite: 15% or less, and the balance: bainite, or second martensite in which less than two iron carbides each having a circle-equivalent diameter of 2 nm to 500 nm are contained in each lath, or the both of these, in which the total area fraction of ND//<111> orientation grains and ND//<100> orientation grains is 40% or less, and the content of solid-solution C is 0.44 ppm or more.

Abstract: A cold-rolled steel sheet has a predetermined chemical composition; a structure of the told-rolled steel sheet at a position which is ¼ of a sheet thickness from a surface contains, in a volume percentage, 80.0% or more of tempered martensite, more than 2.5% and less than 10.0% of residual austenite, 0% or more and 15.0% or less of ferrite and bainite in total, 0% or more and 3.0% or less of martensite, and the remainder structure. With respect to the above-described structure, a maximum value of a random specific intensity Iq is 4.0 or less, an average diameter of a region Rq which has an orientation within 10° from a crystal orientation in which the random specific intensity Iq is maximum is 10.0 ?m or less, a surface density of the region Rq is 1000 pieces/mm2 or more, a tensile strength is 1310 MPa or more, a uniform elongation is 5.0% or more, and TS×? is 35000 MPa·% or more.

Abstract: This high-strength cold-rolled steel sheet has a predetermined chemical composition, wherein a microstructure at a ¼ position of a sheet thickness from a surface includes predetermined ranges of volume percentages of tempered martensite, residual austenite, ferrite and bainite, and martensite, wherein a microstructure at a position 25 ?m from the surface includes, predetermined ranges of volume percentage of ferrite and bainite, and martensite and tempered martensite, wherein in the position 25 ?m from the surface, an average grain size of the martensite and the tempered martensite is 5.0 ?m or less, a tensile strength is 1,310 MPa or more, and a uniform elongation is 5.0% or more, and R/t is 5.0 or less, the R/t being a ratio of a limit bend radius R in 90° V-bending to a sheet thickness t.

Abstract: An objective of the present invention is to provide a front pillar outer that has high strength and high rigidity. In an area in which the first door-side flange part and a second door-side flange part overlap with each other, the first door-side flange part and the second door-side flange part are joined to each other. In an area in which the first glass-face-side flange part and the second glass-face-side flange part overlap with each other, the first glass-face-side flange part and the second glass-face-side flange part are joined to each other.

Abstract: A steel sheet has a predetermined chemical composition, in which a metallographic structure in a surface layer region ranging from a surface to a position of 20 ?m from the surface in a sheet thickness direction consists of ferrite and a secondary phase having a volume fraction of 0.01% to 5.0%, a metallographic structure in an internal region ranging from a position of more than 20 ?m from the surface in the sheet thickness direction to a ¼thickness position from the surface in the sheet thickness direction consists of ferrite and a secondary phase having a volume fraction of 2.0% to 10.0%, the volume fraction of the secondary phase in the surface layer region is less than the volume fraction of the secondary phase in the internal region, and in the surface layer region, an average grain size of the secondary phase is 0.01 ?m to 4.0 ?m, and a texture in which an XODF{001}/{111} as the ratio of the intensity of {001} orientation to an intensity of {111} orientation in the ferrite is 0.

Abstract: An objective of the present disclosure is to provide a front pillar outer that is inexpensive, lightweight and strong. A front pillar outer includes a glass-face-side flange part, a door-side flange part, and a main body part that connects the glass-face-side flange part and the door-side flange part to each other. In a partial area of the door-side flange part in a longitudinal direction thereof, a first plate part that is connected to a side edge of the door-side flange part is folded so that the first plate part is overlaid on the door-side flange part. In a partial area of the glass-face-side flange part in a longitudinal direction thereof, a second plate part that is connected to a side edge of the glass-face-side flange part is folded so that the second plate part is overlaid on the glass-face-side flange part.

Abstract: An objective of the present disclosure is to provide a front pillar outer that is inexpensive, lightweight and strong. In an area in which a first door-side flange part and a second door-side flange part overlap with each other, a first plate part that is connected to a side edge of the first door-side flange part is folded so that a second door-side flange part is sandwiched between the first door-side flange part and the folded first plate part. In an area in which a first glass-face-side flange part and a second glass-face-side flange part overlap with each other, a second plate part that is connected to a side edge of the first glass-face-side flange part is folded so that the second glass-face-side flange part is sandwiched between the first glass-face-side flange part and the folded second plate part.