Abstract: The plated steel material is a plated steel material including a steel material and a plating layer provided on the surface of the steel material, wherein the plating layer has a predetermined average chemical composition, when the amount of Mg is % Mg and the amount of Al is % Al, % Mg/% Al is 0.80 or more, and a metal structure in a total field of view of 25,000 ?m2 in a vertical cross section which is a cross section in a thickness direction of the plating layer includes 10 to 40 area % of a MgZn2 phase, 10 to 30 area % of an Al—Zn phase with a Zn content of 10% or more, 0 to 15 area % of an Al phase with a Zn content of less than 10%, and 25 area % or more of an Al/MgZn2/Zn ternary eutectic structure.

Abstract: The plated steel material is a plated steel material including a steel material and a plating layer provided on the surface of the steel material, wherein the plating layer has a predetermined average chemical composition, when the amount of Mg is % Mg and the amount of Al is % Al, % Mg/% Al is 0.80 or more, and a metal structure in a total field of view of 25,000 ?m2 in a vertical cross section which is a cross section in a thickness direction of the plating layer includes 10 to 40 area % of a MgZn2 phase, 10 to 30 area % of an Al—Zn phase with a Zn content of 10% or more, 0 to 15 area % of an Al phase with a Zn content of less than 10%, and 25 area % or more of an Al/MgZn2/Zn ternary eutectic structure.

Abstract: According to one aspect of the present invention, there is provided a T-joint including a first steel sheet, a second steel sheet, and a fillet welded part, in which the sheet thickness of the second steel sheet is 6.0 mm or less, the second steel sheet is stood on a first surface of the first steel sheet, the fillet welded part joins the first surface of the first steel sheet and a first surface of the second steel sheet to each other, at least one of the first surface of the first steel sheet or the first surface of the second steel sheet includes a zinc-based plating, an abutting end portion of the second steel sheet on a second surface side of the second steel sheet has an inclined surface, and in a cross section taken along a sheet thickness direction of the first steel sheet and a sheet thickness direction of the second steel sheet, the inclined surface forms an acute angle with respect to the first surface of the first steel sheet.

Abstract: Provided is a metallic coated steel product which is less likely to experience LME and blowhole formation and is likely to exhibit an improved corrosion resistance at welding heat affected zones. The metallic coated steel product is a hot-dip metallic coated steel product including a steel product and a plating layer that is provided on a surface of the steel product and includes a Zn—Al—Mg alloy layer. In a cross-section of the Zn—Al—Mg alloy layer an area fraction of MgZn2 phase is from 45 to 75%, a total area fraction of MgZn2 and Al phases is not less than 70%, and an area fraction of Zn—Al—MgZn2 ternary eutectic structure is from 0 to 5%; and the plating layer has a predetermined chemical composition.

Abstract: The present invention provides a lap fillet arc welding joint including a first metal sheet, a second metal sheet, and a weld bead. A region of the first metal sheet on one end side is bent. In a first direction, a position of a tip end of the bent region of the first metal sheet overlaps a region of the second metal sheet on one end side. In a second direction, an amount of deviation between a central axis of a region connected to the bent region of the first metal sheet and a central axis of the region of the second metal sheet on one end side is ½ times or less of average sheet thicknesses of the first metal sheet and the second metal sheet. A joint portion length is two times or more of the sheet thickness of the second metal sheet.

Abstract: In a fillet welded joint a base material tensile strength is 980 MPa or more, a carbon equivalent is 0.36 or more and 0.60 or less, a tensile strength [MPa] is 1950 times or more of the carbon equivalent [wt %], a weld metal average carbon equivalent is 0.45 or more and 0.65 or less, and at a prescribed position below a surface of a weld toe, a Vickers hardness HVbond at a boundary between the weld metal and a heat affected zone, an average value HVwmt of the Vickers hardness of the weld metal in a position 0.1-mm or more and 0.3-mm or less to the weld metal side of the boundary, and an average value HVhaz of the Vickers hardness of the heat affected zone in a position 0.1-mm or more and 0.3-mm or less to the heat affected zone side of the boundary satisfy HVbond?HVwmt, HVbond?HVhaz-50, and HVhaz?350.

Abstract: A high-strength steel sheet having a microstructure represented by, in area %, martensite: 5% or more; ferrite: 20% or more; and pearlite: 5% or less. A ratio of the number of bulging type martensite grains to the number of martensite grains on grain boundary triple points of a matrix is 70% or more, wherein: the bulging type martensite grain is on one of the grain boundary triple points of the matrix; and at least one of grain boundaries of the bulging type martensite grain, the grain boundaries connecting two adjacent grain boundary triple points of the bulging type martensite grain and grains of the matrix, has a convex curvature to an outer side with respect to line segments connecting the two adjacent grain boundary triple points. An area ratio VM/A0 is 1.0 or more.

Abstract: This steel sheet includes a first coated portion in which an intermetallic compound layer and an aluminum coating layer are provided on a surface of a base steel sheet in order from the base steel sheet side, a first exposed portion in which the base steel sheet is exposed, and a second coated portion in which the intermetallic compound layer and the aluminum coating layer are provided on the surface of the base steel sheet in order from the base steel sheet side, in which in a first direction which is perpendicular to a thickness direction of the steel sheet and is directed from the first coated portion to one end edge of the steel sheet, the first coated portion, the first exposed portion, the second coated portion, and the end edge of the steel sheet are disposed in this order on one surface of the base steel sheet, at least the first coated portion, the first exposed portion, and the end edge of the steel sheet are disposed in this order on the other surface of the base steel sheet in the first direction,

Abstract: Provided is a metallic coated steel product which is less likely to experience LME and blowhole formation and is likely to exhibit an improved corrosion resistance at welding heat affected zones. The metallic coated steel product is a hot-dip metallic coated steel product including a steel product and a plating layer that is provided on a surface of the steel product and includes a Zn—Al—Mg alloy layer. In a cross-section of the Zn—Al—Mg alloy layer an area fraction of MgZn2 phase is from 45 to 75%, a total area fraction of MgZn2 and Al phases is not less than 70%, and an area fraction of Zn—Al—MgZn2 ternary eutectic structure is from 0 to 5%; and the plating layer has a predetermined chemical composition.

Abstract: The present invention relates to a fillet welded joint and a manufacturing method thereof, and addresses the problem of providing a fillet welded joint having excellent weld fatigue strength while suppressing low temperature cracking. In a fillet welded joint according to the present invention, a tensile strength of a base material is 980 MPa or more, a carbon equivalent is 0.36 or more and 0.60 or less, a tensile strength [MPa] is 1950 times or more of the carbon equivalent [wt%], an average carbon equivalent of weld metal is 0.45 or more and 0.65 or less, and at a prescribed position below a surface of a weld toe, a Vickers hardness HVbond at a boundary between the weld metal and a heat affected zone, an average value HVwmt of the Vickers hardness of the weld metal in a position 0.1 mm or more and 0.3 mm or less to the weld metal side of the boundary, and an average value HVhaz of the Vickers hardness of the heat affected zone in a position 0.1 mm or more and 0.

Abstract: A steel sheet includes: a base iron; a scale of 10.0 ?m or less in thickness on a surface of the base iron; a subscale between the base iron and the scale. In the subscale, an average value of Cr concentrations is 1.50 mass % to 5.00 mass %, and one part or more exist(s) where a ratio of Cr concentrations between two adjacent measurement regions separate by 1 ?m is 0.90 or less or 1.11 or more in a range of 50 ?m in length in a rolling direction. A percentage of an amount of Ti contained in carbide or carbonitride of 100 nm or more and 1 ?m or less in grain diameter to a parameter Tieff represented by a formula “Tieff=[Ti]?48/14[N]” is 30% or less in which [Ti] denotes a Ti content (mass %) and [N] denotes a N content (mass %).

Abstract: The present invention provides a lap fillet arc welding joint including a first metal sheet, a second metal sheet, and a weld bead. A region of the first metal sheet on one end side is bent. In a cross-sectional view in a cross section perpendicular to a weld line of the weld bead, in a first direction, a position of a tip end of the bent region of the first metal sheet overlaps a region of the second metal sheet on one end side. In a second direction, an amount of deviation between a central axis of a region connected to the bent region of the first metal sheet and a central axis of the region of the second metal sheet on one end side is ½ times or less of the average value of sheet thicknesses of the first metal sheet and the second metal sheet. A joint portion length, which is a length from a root portion of the second metal sheet to a weld toe portion of the first metal sheet, is two times or more of the sheet thickness of the second metal sheet.

Abstract: Stiffening beads (55A, 55B) are formed in turned portions in a region of a fillet bead (53) formed in a single stroke manner. At this time, it is set in such a manner that welding start positions of the stiffening beads (55A, 55B) are in a region near the fillet bead and do not exist independently without mixing with other weld beads.

Abstract: A high-strength steel sheet includes a specific chemical composition, and a microstructure represented by, in area %, martensite: 5% or more; ferrite: 20% or more; and perlite: 5% or less. An average diameter of martensite grain is 4 ?m or less in equivalent circle diameter. A ratio of the number of bulging type martensite grains to the number of martensite grains on grain boundary triple points of a matrix is 70% or more, wherein: the bulging type martensite grain is on one of the grain boundary triple points of the matrix; and at least one of grain boundaries of the bulging type martensite grain, the grain boundaries connecting two adjacent grain boundary triple points of the bulging type martensite grain and grains of the matrix, has a convex curvature to an outer side with respect to line segments connecting the two adjacent grain boundary triple points. An area ratio represented by VM/A0 is 1.

Abstract: At least one stiffening bead (32) is formed by arc welding on a surface of at least one of metal members in addition to a fillet bead (3) formed by fillet arc welding. The stiffening bead (32) is formed to have an angle of 45° to 135° with respect to the fillet bead (3) and to overlap with the fillet bead (3). The sum total l1 of lengths of stiffening beads (32) can be, for example, 0.5 times or more of a length L of the fillet bead (3).

Abstract: A steel sheet includes: a base iron; a scale of 10.0 ?m or less in thickness on a surface of the base iron; a subscale between the base iron and the scale. In the subscale, an average value of Cr concentrations is 1.50 mass % to 5.00 mass %, and one part or more exist(s) where a ratio of Cr concentrations between two adjacent measurement regions separate by 1 ?m is 0.90 or less or 1.11 or more in a range of 50 ?m in length in a rolling direction. A percentage of an amount of Ti contained in carbide or carbonitride of 100 nm or more and 1 ?m or less in grain diameter to a parameter Tieff represented by a formula “Tieff=[Ti]?48/14[N]” is 30% or less in which [Ti] denotes a Ti content (mass %) and [N] denotes a N content (mass %).

Abstract: Stiffening beads (55A, 55B) are formed in turned portions in a region of a fillet bead (53) formed in a single stroke manner. At this time, it is set in such a manner that welding start positions of the stiffening beads (55A, 55B) are in a region near the fillet bead and do not exist independently without mixing with other weld beads.

Abstract: At least one stiffening bead (32) is formed by arc welding on a surface of at least one of metal members in addition to a fillet bead (3) formed by fillet arc welding. The stiffening bead (32) is formed to have an angle of 45° to 135° with respect to the fillet bead (3) and to overlap with the fillet bead (3). The sum total l1 of lengths of stiffening beads (32) can be, for example, 0.5 times or more of a length L of the fillet bead (3).

Abstract: A stainless steel flux-cored welding wire for zinc-coated steel sheet welding use which gives a weld zone where no zinc embrittlement cracking occurs and the corrosion resistance and ductility are excellent and which is good in weld work efficiency and a welding method using the same, the welding wire characterized in that total amounts of elements which are included as metals or alloy compositions in the sheath and flux are, by mass % with respect to a total mass of the welding wire, C: 0.01 to 0.05%, Si: 0.1 to 1.5%, Mn: 0.5 to 3.0%, Ni: 7.0 to 10.0%, and Cr: 26.0 to 30.0%, an F value is 30 to 50 in range, further, the wire contains, as slag forming agents, in the flux, by mass % with respect to the total mass of the wire, TiO2: 3.8 to 6.8%, SiO2: 1.8 to 3.2%, ZrO2: 1.3% or less, and Al2O3: 0.5% or less, a total amount of the slag forming agent and other slag forming agents is 7.5 to 10.

Abstract: A stainless steel flux-cored welding wire for zinc-coated steel sheet welding use which gives a weld zone where no zinc embrittlement cracking occurs and the corrosion resistance and ductility are excellent and which is good in weld work efficiency and a welding method using the same, the welding wire characterized in that total amounts of elements which are included as metals or alloy compositions in the sheath and flux are, by mass % with respect to a total mass of the welding wire, C: 0.01 to 0.05%, Si: 0.1 to 1.5%, Mn: 0.5 to 3.0%, Ni: 7.0 to 10.0%, and Cr: 26.0 to 30.0%, an F value is 30 to 50 in range, further, the wire contains, as slag forming agents, in the flux, by mass % with respect to the total mass of the wire, TiO2: 3.8 to 6.8%, SiO2: 1.8 to 3.2%, ZrO2: 1.3% or less, and Al2O3: 0.5% or less, a total amount of the slag forming agent and other slag forming agents is 7.5 to 10.