Abstract: Provided are a steel sheet having a predetermined chemical composition, and a steel microstructure comprising, by vol %, ferrite: 1 to 50%, ratio of nonrecrystallized ferrite in the ferrite: 0 to 50%, tempered martensite: 1% or more, retained austenite: 5% or more, fresh martensite: 0 to 10%, total of pearlite and cementite: 0 to 5%, and balance: bainite, and, when analyzing the surface by an EPMA, an area ratio of regions with an AlS/SiS ratio of 0.2 or less is 50% or less, and a tensile strength is 980 MPa or more, and a method for producing the same.

Abstract: This steel sheet has a predetermined chemical composition, in which a microstructure at a ¼ depth position of a sheet thickness from a surface of the steel sheet contains, by volume fraction, ferrite: 0% to 50%, residual austenite: 6% to 30%, bainite: 5% to 60%, tempered martensite: 5% to 50%, fresh martensite: 0% to 10%, and pearlite: 0% to 5%, at the ¼ depth position of the sheet thickness from the surface, a number proportion of the residual austenite having an aspect ratio of 2.0 or more to an entire residual austenite is 50% or more, and a number density of inclusions and precipitates having a grain size of 1 ?m or more is 30/mm2 or less, and at a 1/20 depth position of the sheet thickness from the surface, an average interval between Mn-concentrated portions in a direction perpendicular to a rolling direction is 300 ?m or less, and a standard deviation of Mn concentrations in the residual austenite is 0.40% or less.

Abstract: This hot rolled steel sheet has a predetermined chemical composition, in which the microstructure contains, by area%, polygonal ferrite: 2.0% or more and less than 10.0% and the remainder in the microstructure: more than 90.0% and 98.0% or less, and a correlation value that is obtained by analyzing the remainder in the microstructure in a SEM image of the microstructure is 0.82 to 0.95, and a maximum probability value is 0.0040 to 0.0200.

Abstract: There is provided a surface shape defect generating region estimating method for estimating a generating region of a surface shape defect of a deformation-processed product obtained by performing deformation processing with respect to a workpiece, the method including: a first stress distribution obtaining process of obtaining first stress distribution ?(T1); a second stress distribution obtaining process of obtaining a second stress distribution ?(T2); a comparative stress distribution obtaining process of obtaining comparative stress distribution ?(T1, T2); a division comparative stress distribution obtaining process of obtaining division comparative stress distribution ?DIV(T1, T2); and a surface shape defect generating region estimating process of estimating whether or not each of the divided regions DK is a generating region of the surface shape defect.

Abstract: A laser welded joint has weld metal provided between a plurality of steel sheets. A chemical composition of the weld metal has predetermined components, and average hardness of the weld metal is 350 to 540 in Vickers hardness. In the weld metal, distribution density of porosities having a diameter of 2 ?m to 50 ?m is equal to or less than 5.0 pieces/mm2. In the weld metal, distribution density of oxide inclusions having a diameter of 3 ?m or more is 0.1 to 8.0 pieces/mm2.

Abstract: Disclosed is a press forming method press forming a workpiece between a die and a punch, while pushing the punch into the die by means of a relative motion of the die and the punch, the method includes: producing an intermediate molding (100B) having ridges (100d) formed in predetermined parts of the workpiece, and then press forming the intermediate molding (100B) into a final shape, to thereby substantially thicken and work-harden the predetermined parts of the workpiece.

Abstract: The present invention provides a high-strength steel sheet excellent in shape fixability. The high-strength steel sheet contains C, Si, Mn, P, S, Al, N, and O with predetermined contents, in which a retained austenite phase of 5 to 20% in volume fraction is contained, an amount of solid-solution C contained in the retained austenite phase is 0.80 to 1.00% in mass %, WSi? is 1.10 times or more WSi*, WMn? is 1.10 times or more WMn*, and when a frequency distribution is measured with respect to a sum of a ratio between WSi and WSi* and a ratio between WAl and WAl*, a mode value of the frequency distribution is 1.95 to 2.05, and a kurtosis is 2.00 or more.

Abstract: A bending fracture limit stress is calculated for each of (bend radius at sheet thickness center of a metal sheet)/(initial sheet thickness of the metal sheet); a fracture limit curve and a fracture limit stress are calculated from work hardening characteristics; a fracture limit curve corresponding to (the metal sheet bend radius at sheet thickness center)/(the initial sheet thickness of the metal sheet) is calculated; a corresponding fracture limit stress is calculated from stress of the element subject to determination and the fracture limit curve; a risk ratio that is a ratio between the stress of the element subject to determination and the fracture limit stress is computed; and performing fracture determination for the element subject to determination based on the risk ratio.

Abstract: A surface mount type quartz crystal device according to a first aspect of the disclosure includes a ceramic package, a pedestal blank, a quartz-crystal vibrating piece. The pedestal blank is placed within the ceramic package via a conductive adhesive. The quartz-crystal vibrating piece is placed on the pedestal blank. The conductive adhesive is formed along an outer peripheral side of the pedestal blank so as to avoid overlap with the excitation electrode viewed in a normal direction of the excitation electrode. The pedestal blank is formed to avoid a region where a distance from the quartz-crystal vibrating piece is equal to or smaller than a size of a clearance between the pedestal blank and the quartz-crystal vibrating piece at the outer peripheral side, in a region where the excitation electrode faces at the pedestal blank side viewed in the normal direction.

Abstract: There is provided a surface shape defect generating region estimating method for estimating a generating region of a surface shape defect of a deformation-processed product obtained by performing deformation processing with respect to a workpiece, the method including: a first stress distribution obtaining process of obtaining first stress distribution ?T1; a second stress distribution obtaining process of obtaining a second stress distribution ?(T2); a comparative stress distribution obtaining process of obtaining comparative stress distribution ?(T1, T2); a division comparative stress distribution obtaining process of obtaining division comparative stress distribution ?(T1, T2); and a surface shape defect generating region estimating process of estimating whether or not each of the divided regions DK is a generating region of the surface shape defect.

Abstract: A laser welded joint has weld metal provided between a plurality of steel sheets. A chemical composition of the weld metal has predetermined components, and average hardness of the weld metal is 350 to 540 in Vickers hardness. In the weld metal, distribution density of porosities having a diameter of 2 ?m to 50 ?m is equal to or less than 5.0 pieces/mm2. In the weld metal, distribution density of oxide inclusions having a diameter of 3 ?m or more is 0.1 to 8.0 pieces/mm2.

Abstract: There is provided a high-strength hot-dip galvanized steel sheet and the like excellent in mechanical cutting property, which are capable of obtaining high ductility while ensuring high strength with maximum tensile strength of 900 MPa or more. The high-strength hot-dip galvanized steel sheet has a sheet thickness of 0.6 to 5.0 mm and has a plating layer on a surface of a steel sheet with component compositions being set in appropriate ranges, in which the steel sheet structure contains a 40 to 90% ferrite phase and a 3% or more retained austenite phase by volume fraction. In the retained austenite phase, a solid solution carbon amount is 0.70 to 1.00%, an average grain diameter is 2.0 ?m or less, an average distance between grains is 0.1 to 5.0 ?m, a thickness of a decarburized layer in a steel sheet surface layer portion is 0.01 to 10.0 ?m, an average grain diameter of oxides contained in the steel, sheet surface layer portion is 30 to 120 nm and an average density thereof is 1.

Abstract: A base steel sheet has a hot-dip galvanized layer formed on a surface thereof, in which, in a steel sheet structure in a range of ? thickness to ? thickness centered around ¼ thickness of a sheet thickness from a surface, a volume fraction of a retained austenite phase is 5% or less, and a total volume fraction of phases of bainite, bainitic ferrite, fresh martensite, and tempered martensite is 40% or more, an average effective crystal grain diameter is 5.0 ?m or less, a maximum effective crystal grain diameter is 20 ?m or less, and a decarburized layer with a thickness of 0.01 ?m to 10.0 ?m is formed on a surface layer portion, in which a density of oxides dispersed in the decarburized layer is 1.0×1012 to 1.0×1016 oxides/m2, and an average grain diameter of the oxides is 500 nm or less.

Abstract: High strength steel sheet which secures tensile maximum strength 900 MPa or more high strength while having excellent shapeability, which high strength steel sheet which is excellent in shapeability characterized by having a predetermined composition of ingredients, by the steel sheet structure including a ferrite phase and martensite phase, by the ratio of Cu particles incoherent with the bcc iron being 15% or more with respect to the Cu particles as a whole, by a density of Cu particles in the ferrite phase being 1.0×1018/m3 or more, and by an average particle size of Cu particles in the ferrite phase being 2.0 nm or more.

Abstract: Disclosed is a press forming method press forming a workpiece between a die and a punch, while pushing the punch into the die by means of a relative motion of the die and the punch, the method includes: producing an intermediate molding (100B) having ridges (100d) formed in predetermined parts of the workpiece, and then press forming the intermediate molding (100B) into a final shape, to thereby substantially thicken and work-harden the predetermined parts of the workpiece.

Abstract: Disclosed is a press forming method press forming a workpiece between a die and a punch, while pushing the punch into the die by means of a relative motion of the die and the punch, the method includes: producing an intermediate molding (100B) having ridges (100d) formed in predetermined parts of the workpiece, and then press forming the intermediate molding (100B) into a final shape, to thereby substantially thicken and work-harden the predetermined parts of the workpiece.

Abstract: A bending fracture limit stress is calculated for each of (bend radius at sheet thickness center of a metal sheet)/(initial sheet thickness of the metal sheet); a fracture limit curve and a fracture limit stress are calculated from work hardening characteristics; a fracture limit curve corresponding to (the metal sheet bend radius at sheet thickness center)/(the initial sheet thickness of the metal sheet) is calculated; a corresponding fracture limit stress is calculated from stress of the element subject to determination and the fracture limit curve; a risk ratio that is a ratio between the stress of the element subject to determination and the fracture limit stress is computed; and performing fracture determination for the element subject to determination based on the risk ratio.

Abstract: The present invention provides a high-strength galvanized steel sheet with maximum tensile strength of 900 MPa or more. The high-strength galvanized steel sheet has an alloyed galvanized layer formed on a surface of a base steel sheet containing predetermined amounts of C, Si, Mn, P, S, Al, N, O with a balance being constituted of iron and inevitable impurities, in which in a structure of the base steel sheet, retained austenite is limited to 8% or less in volume fraction, kurtosis K* of the hardness distribution between 2% hardness and 98% hardness is ?0.30 or less, a ratio between Vickers hardness of surface layer of the base steel sheet and Vickers hardness of ¼ thickness of the base steel sheet is 0.35 to 0.70, and a content of iron in the alloyed galvanized layer is 8 to 12% in mass %.

Abstract: A vehicle frame member structure has a closed cross-sectional structure including a pair of first wall portions, and a pair of second wall portions connected to the pair of the first wall portions, in which first beads are provided on the pair of first wall portions along a circumferential direction of the closed cross-sectional structure, a second bead is provided on either of the pair of second wall portions along the closed cross-sectional circumferential direction on a line extending from the first bead in the circumferential direction, the first and second beads are connected in two corner portions between the first wall portions and the second wall portion, a recessed embossed portion is provided in a connection portion of the first and second beads in at least one of the corner portions, and the sheet thickness of the embossed portion is larger than that of the first or second wall portion.

Abstract: Steel contains each of C, Si, Mn, P, S, Al, N, O, at a range from ? thickness centered around a ¼ sheet thickness from a surface to ? thickness centered around the ¼ sheet thickness from the surface at a base steel sheet, a structure of the base steel sheet contains, in volume fraction, 3% or more of a retained austenite phase, 50% or less of a ferrite phase, and 40% or more of a hard phase, average dislocation density is 5×1013/m2 or more, solid-solution C amount contained in the retained austenite phase is in mass % 0.70 to 1.00%, X-ray random intensity ratio of FCC iron in an texture of the retained austenite phase is 3.0 or less, ratio between a grain diameter relative to a rolling direction and a grain diameter relative to a sheet width direction of the retained austenite phase is 0.75 to 1.33.