Abstract: A nickel-containing steel for low temperature service having a determined chemical composition of a Ni content of from 5.0 to 8.0%, in which the volume fraction of retained austenite in a region of 1.5 mm from a surface in the thickness direction is from 3.0 to 20.0% by volume, and the ratio of the hardness in a region of 1.0 mm from a surface in the thickness direction to the hardness in a region of ¼ of the thickness from a surface in the thickness direction is 1.1 or less, and a low-temperature tank using the nickel-containing steel for low temperature service.

Abstract: A method for manufacturing a quenched molding according to the present disclosure is a method including a first heat treatment process of heating a blanked steel material to a temperature higher than its Ac3 transformation point to perform austenite transformation, and then cooling to induce martensite transformation or bainite transformation, and a second heat treatment process of heating the steel material that has undergone the first heat treatment process to a temperature higher than the Ac3 transformation point to perform austenite transformation, and then cooling to induce martensite transformation. After the steel material has been heated to a temperature higher than the Ac3 transformation point in at least one process from out of the first heat treatment process or the second heat treatment process, molding is completed at a temperature higher than an Ar3 transformation point.

Abstract: A blank material is formed from a steel sheet, a first quenching of the blank material is performed, and a second quenching of the blank material is performed after the first quenching. When the first quenching is performed, the blank material is heated to a first temperature of not lower than (Ac3 point—50)° C. nor higher than 1200° C. at an average heating rate of 2° C./sec or more, and the blank material is cooled from the first temperature to a second temperature of 250° C. or lower. When the second quenching is performed, the blank material is heated from the second temperature to a third temperature of not lower than (Ac3 point—50)° C. nor higher than 1200° C. at an average heating rate of 2° C./sec or more, and the blank material is cooled from the third temperature to a fourth temperature of 250° C. or lower. Forming of the blank material is performed in the first quenching or the second quenching or both of the above.

Abstract: A steel sheet includes a predetermined chemical composition, and includes a steel structure represented by, in a volume fraction, tempered martensite and bainite: 70% or more and less than 92% in total, retained austenite: 8% or more and less than 30%, ferrite: less than 10%, fresh martensite: less than 10%, and pearlite: less than 10%. A number density of iron-base carbides in tempered martensite and lower bainite is 1.0×106 (pieces/mm2) or more, and an effective crystal grain diameter of tempered martensite and bainite is 5 ?m or less.

Abstract: This invention provides a ferritic heat transfer member and a heat resistant ferritic steel which are excellent in heat transfer characteristics and steam oxidation resistance properties. The heat resistant ferritic steel includes a base material, and an oxidized layer A on the surface of the base material. The base material has a chemical composition containing, in mass %: C: 0.01 to 0.3%, Si: 0.01 to 2.0%, Mn: 0.01 to 2.0%, Cr: 7.0 to 14.0%, N: 0.005 to 0.15%, and sol. Al: 0.001 to 0.3%, and one or more types of element selected from the specific oxidized layer forming elements of 0.5 to 7.0%, with the balance being Fe and impurities. An oxidized layer A includes a chemical composition containing, in mass %: Cr and Mn in a total amount of 20 to 45%, and one or more types of element selected from the specific oxidized layer forming elements of 0.5 to 10%.

Abstract: Provided is a SiC single crystal that has a large growth thickness and contains no inclusions. A SiC single crystal grown by a solution process, wherein the total length M of the outer peripheral section formed by the {1-100} faces on the {0001} growth surface of the SiC single crystal, and the length P of the outer periphery of the growth surface of the SiC single crystal, satisfy the relationship M/P?0.70, and the length in the growth direction of the SiC single crystal is 2 mm or greater.

Abstract: A steel sheet has a specific chemical composition and has a structure represented by, by area ratio, ferrite: 5 to 60%, and bainite: 40 to 95%. When a region that is surrounded by a grain boundary having a misorientation of 15° or more and has a circle-equivalent diameter of 0.3 ?m or more is defined as a crystal grain, the proportion of crystal grains each having an intragranular misorientation of 5 to 14° to all crystal grains is 20 to 100% by area ratio. A precipitate density of Ti(C,N) and Nb(C,N) each having a circle-equivalent diameter of 10 nm or less is 1010 precipitates/mm3 or more. A ratio (Hvs/Hvc) of a hardness at 20 ?m in depth from a surface (Hvs) to a hardness of the center of a sheet thickness (Hvc) is 0.85 or more.

Abstract: The Sn-plated steel sheet of the disclosure is an Sn-plated steel sheet including: a steel sheet; an Sn plating layer formed on at least one side of the steel sheet and containing, based on % by mass, from 0.1 g/m2 to 15 g/m2 of metal Sn; and a coating layer formed on the surface of the Sn plating layer and containing zirconium oxide and tin oxide; in which the content of the zirconium oxide in the coating layer is from 0.2 mg/m2 to 50 mg/m2 in terms of metal Zr amount, and the peak position of binding energy of Sn3d5/2 according to X-ray photoelectron spectroscopy of the tin oxide in the coating layer is 1.6 eV or higher than the peak position of binding energy of the metal Sn.

Abstract: The present invention provides a hot-stamping formed article which is long and formed of a single steel sheet, the hot-stamping formed article including: two standing wall portions; a top sheet portion adjacent to the two standing wall portions; and a protrusion portion including an overlapping portion in which a portion of the steel sheet extending from at least one standing wall portion of the two standing wall portions and a portion of the steel sheet extending from the top sheet portion overlap, in which an angle between the top sheet portion and the protrusion portion in a case where a plane perpendicular to a longitudinal direction of the hot-stamping formed article is viewed in a cross section is larger than 90°.

Abstract: To provide a titanium sheet excellent in formability and a method for manufacturing the same. A titanium sheet, wherein, when a carbon concentration of a base material is Cb (mass %) and a carbon concentration at a depth d ?m from a surface is Cd (mass %), the depth d (carbon concentrated layer thickness) satisfying Cd/Cb>1.5 is 1.0 ?m or more and less than 10.0 ?m or less, wherein a Vickers hardness HV0.025 at a load of 0.245 N in the surface is 200 or more, a Vickers hardness HV0.05 at a load of 0.49 N in the surface is lower than HV0025, and a difference between HV0.025 and HV0.05 is 30 or more, wherein a Vickers hardness HV1 at a load of 9.8 N in the surface is 150 or less, and wherein an average interval between cracks generated in the surface when a strain of 25% is given in a rolling direction in a bulging forming process is less than 50 ?m and a depth thereof is 1 ?m or more and less than 10 ?m.

Abstract: An oil well pipe for expandable tubular, containing, in terms of % by mass: 0.020 to 0.080% of C, 0.50% or less of Si, 0.30 to 1.60% of Mn, 0.030% or less of P, 0.010% or less of S, 0.005 to 0.050% of Ti, and 0.010 to 0.500% of Al, and the balance being Fe and impurities, wherein, in a metallographic microstructure, an area fraction of a first phase composed of ferrite is from 90.0% to 98.0% and an area fraction of a second phase composed of one or more selected from the group consisting of tempered martensite, tempered bainite, and pearlite is from 2.0% to 10.0%.

Abstract: The Sn-based alloy plated steel sheet of this disclosure includes: a steel sheet; a composite plating layer formed on at least one side of the steel sheet and including an Fe—Ni—Sn alloy layer and an island-shaped Sn layer located on the Fe—Ni—Sn alloy layer; and a coating layer formed on the surface of the composite plating layer and containing zirconium oxide and tin oxide, and the composite plating layer contains a predetermined amount of Ni and a predetermined amount of Sn, a content of the zirconium oxide in the coating layer is from 0.2 mg/m2 to 50 mg/m2 in terms of metal Zr amount, and a peak position of binding energy of Sn3d5/2 according to X-ray photoelectron spectroscopy of the tin oxide in the coating layer is 1.6 eV or higher than a peak position of binding energy of the metal Sn.

Abstract: A steel for machine structural use according to the present embodiment has a chemical composition which consists of, in mass %, C: 0.30 to 0.50%, Si: 0.01 to 0.80%, Mn: 0.20 to 2.00%, P: 0.030% or less, S: 0.010 to 0.100%, Pb: 0.010 to 0.100%, Al: 0.010 to 0.050%, N: 0.015% or less, O: 0.0005 to 0.0030% and Cr: more than 0.70% to 2.00%, with the balance being Fe and impurities, the chemical composition satisfying Formula (1). The total number of specific inclusions included in the steel which are any of MnS inclusions, Pb inclusions and composite inclusions containing MnS and Pb and which have an equivalent circular diameter of 5 ?m or more is 40 per mm2 or more. Mn/S?8.0??(1) Where, a content (mass %) of a corresponding element is substituted for each symbol of an element in Formula (1).

Abstract: The present invention has as its object the provision of steel sheet for hot stamping use which is excellent in part strength after hot stamping and delayed fracture resistance comprised of large C content high strength steel sheet in which effective hydrogen traps are formed in the steel material. The steel sheet of the present invention solves this problem by forming Fe—Mn-based composite oxides in the steel sheet and trapping hydrogen at the interfaces of the composite oxides and matrix steel and in the voids around the composite oxides. Specifically, it provides steel sheet for hot stamping use which is comprised of chemical ingredients which contain, by mass %, C: 0.05 to 0.40%, Si: 0.02% or less, Mn: 0.1 to 3%, S: 0.02% or less, P: 0.03% or less, Al: 0.005% or less, Ti: 0.01% or less, N: 0.01% or less, one or both of Cr and Mo in a total of 0.005 to 1%, and O: 0.003 to 0.03% and which have a balance of Fe and unavoidable impurities and which contains average diameter 0.

Abstract: A steel for cold forging has a predetermined chemical composition, satisfies d+3??10.0 and SA/SB<0.30, includes 1200/mm2 or more of sulfides having an equivalent circle diameter of 1.0 to 10.0 ?m in a microstructure, and has an average distance between the sulfides of less than 30.0 ?m. Here, d is an average value of equivalent circle diameters of sulfides having an equivalent circle diameter of 1.0 ?m or more, ? is a standard deviation of the equivalent circle diameters of the sulfides having an equivalent circle diameter of 1.0 ?m or more, SA is the number of sulfides having an equivalent circle diameter of 1.0 ?m or more and less than 3.0 ?m, and SB is the number of the sulfides having an equivalent circle diameter of 1.0 ?m or more.

Abstract: A steel according to an aspect of the present invention includes, as a chemical composition, by unit mass %, C: 0.15% to 0.40%, Mn: 0.10% to 1.50%, S: 0.002% to 0.020%, Ti: 0.005% to 0.050%, B: 0.0005% to 0.0050%, Bi: 0.0010% to 0.0100%, P: 0.020% or less, N: 0.0100% or less, Si: 0% or more and less than 0.30%, Cr: 0% to 1.50%, Al: 0% to 0.050%, Mo: 0% to 0.20%, Cu: 0% to 0.20%, Ni: 0% to 0.20%, Nb: 0% to 0.030%, and a remainder including Fe and impurities.

Abstract: A steel sheet includes a predetermined chemical composition and a metal structure represented by, in area fraction, ferrite: 50% to 95%, granular bainite: 5% to 48%, tempered martensite: 2% to 30%, upper bainite, lower bainite, fresh martensite, retained austenite, and pearlite: 5% or less in total, and the product of the area fraction of the tempered martensite and a Vickers hardness of the tempered martensite: 800 to 10500.

Abstract: A resistance spot welding method able to form a welded joint having delayed fracture resistance, comprising, in order, a step of applying a pressing force P1 (kN) to the plurality of steel sheets by welding electrodes while supplying a supplied current I1 (kA), a step of, while applying the pressing force P1, supplying a current Ic (kA) during a cooling time tc (s), a step of repeating two times or more a pressure force raising and lowering cycle of supplying a supplied current I2 (kA) to the welding electrodes while applying a pressing force P2 (kN) to the plurality of steel sheets by the welding electrodes during a pressing time tf (s), then immediately applying a pressing force P3 (kN) during a pressing time ti (s), a step of applying the pressing force P2 during the pressing time tf, and a step of releasing the pressing force and ending the supply of current, satisfying 0?Ic<I1, 0.3?I2/I1<1.0, P2/P1?1.2, P3<P2, and ti?0.2.

Abstract: A steel sheet has a specific chemical composition and has a structure represented by, by area ratio, ferrite: 0 to 30%, and bainite: 70 to 100%. When a region that is surrounded by a grain boundary having a misorientation of 15° or more and has a circle-equivalent diameter of 0.3 ?m or more is defined as a crystal grain, the proportion of crystal grains each having an intragranular misorientation of 5 to 14° to all crystal grains is 20 to 100% by area ratio. A grain boundary number density of solid-solution C or a grain boundary number density of the total of solid-solution C and solid-solution B is 1 piece/nm2 or more and 4.5 pieces/nm2 or less. An average grain size of cementite precipitated at grain boundaries is 2 ?m or less.

Abstract: The present invention provides a method for shear processing whereby a sheared surface having a small residual stress and excellent surface properties is formed and the service life of a punch is prolonged in a shear processing for shearing, by a shear line that crosses a weld zone, a workpiece with a large thickness of level difference of a weld zone and/or obtained by welding together a steel sheet having a strength of 1000 MPa or more and another steel sheet. The shearing for shear processing method according to the present invention is a method for shearing a workpiece having a weld zone using a punch and a die, the method characterized in that two protrusions are provided to a cutting edge of the punch, all or part of the weld zone of the workpiece is flanked from the two sides by the two protrusions, and the workpiece is sheared by a shear line that crosses the weld zone.