Abstract: The present invention provides a method for obtaining a carburized part using steel high in content of Cr and realizing bending fatigue strength at an extremely high level by vacuum carburizing. The carburized part is obtained by treating a steel material having a predetermined chemical composition by vacuum carburizing provided with a carburizing period of 10 to 200 minutes at 850 to 1100° C. and a diffusion period of 15 to 300 minutes at 850 to 1100° C., then quenching and tempering it.

Abstract: Provided are a bolt that exhibits excellent delayed fracture resistance at a high strength level of from 1,200 MPa to less than 1,600 MPa in tensile strength, where the possibility of delayed fracture is generally quite high, and a steel material for a bolt to be used as the material for such a bolt. The bolt has a composition satisfying Formulae (1) and (2), and a tensile strength of from 1,200 MPa to less than 1,600 MPa. In Formula (1) and Formula (2), Mo and V represent the contents (% by mass) of Mo and V contained in the steel for a bolt, respectively. 0.48?Mo/1.4+V<1.10 ??(1) 0.8<Mo/V<3.

Abstract: The present invention provides a method for obtaining a carburized part using steel high in content of Cr and realizing bending fatigue strength at an extremely high level by vacuum carburizing. The carburized part is obtained by treating a steel material having a predetermined chemical composition by vacuum carburizing provided with a carburizing period of 10 to 200 minutes at 850 to 1100° C. and a diffusion period of 15 to 300 minutes at 850 to 1100° C., then quenching and tempering it.

Abstract: A predetermined composition is had, when a C content is represented by (C %), in a case of (C %) being not less than 0.35% nor more than 0.65%, a volume fraction of pearlite is 64×(C %)+52% or more, and in a case of (C %) being greater than 0.65% and 0.85% or less, the volume fraction of pearlite is not less than 94% nor more than 100%, and a structure of the other portion is composed of one or two of proeutectoid ferrite and bainite. Further, in a region to a depth of 1.0 mm from a surface, a volume fraction of pearlite block having an aspect ratio of 2.0 or more is not less than 70% nor more than 95%, and a volume fraction of pearlite having an angle between an axial direction and a lamellar direction on a cross section parallel to the axial direction of 40° or less is 60% or more with respect to all pearlite.

Abstract: A predetermined composition is had, when a C content is represented by (C %), in a case of (C %) being not less than 0.35% nor more than 0.65%, a volume fraction of pearlite is 64×(C %)+52% or more, and in a case of (C %) being greater than 0.65% and 0.85% or less, the volume fraction of pearlite is not less than 94% nor more than 100%, and a structure of the other portion is composed of one or two of proeutectoid ferrite and bainite. Further, in a region to a depth of 1.0 mm from a surface, a volume fraction of pearlite block having an aspect ratio of 2.0 or more is not less than 70% nor more than 95%, and a volume fraction of pearlite having an angle between an axial direction and a lamellar direction on a cross section parallel to the axial direction of 40° or less is 60% or more with respect to all pearlite.

Abstract: A predetermined composition is had, when a C content is represented by (C %), in a case of (C %) being not less than 0.35% nor more than 0.65%, a volume fraction of pearlite is 64×(C %)+52% or more, and in a case of (C %) being greater than 0.65% and 0.85% or less, the volume fraction of pearlite is not less than 94% nor more than 100%, and a structure of the other portion is composed of one or two of proeutectoid ferrite and bainite. Further, in a region to a depth of 1.0 mm from a surface, a volume fraction of pearlite block having an aspect ratio of 2.0 or more is not less than 70% nor more than 95%, and a volume fraction of pearlite having an angle between an axial direction and a lamellar direction on a cross section parallel to the axial direction of 40° or less is 60% or more with respect to all pearlite.

Abstract: According to an aspect of the present invention, there is provided a steel containing, by unit mass %, C: 0.08% to 0.12%, Si: 0.05% to 0.50%, Mn: 1.50% to 3.00%, P: 0.040% or less, S: 0.020% or less, V: 0.010% or less, Ti: 0.010% or less, Nb: 0.005% or less, Cr: 1.00% to 2.50%, Cu: 0.01% to 0.50%, Ni: 0.75% to 1.60%, Mo: 0.10% to 0.50%, Al: 0.025% to 0.050%, N: 0.0100% to 0.0200%, Ca: 0% to 0.0100%, Zr: 0% to 0.0100%, Mg: 0% to 0.0100%, and a remainder including Fe and impurities, in which a ratio of an Al content to a N content is 2.6 or less, a ratio of a Mn content to a Ni content is 1.5 or more and 3.0 or less.

Abstract: A high-strength steel member having a predetermined chemical composition, having a tensile strength of 1,000 MPa or higher, containing 0.10% or more of, in terms of percent (%) by area, at least one Ti precipitate that has an average size of from 30 to 200 nm in terms of an average equivalent circle diameter and is selected from the group consisting of a Ti carbide, a Ti nitride, and a composite compound thereof, at a location of 1 mm in depth from a surface of the steel member, and containing 0.5 ppm by mass or more of non-diffusible hydrogen that is released in a temperature range of from 400 to 800° C. in a thermal desorption hydrogen analysis.

Abstract: Provided is a steel for carbonitrided bearing which excels in hardenability and also excels in toughness, wear resistance, and surface-originated flaking life after quenching and tempering. A steel for carbonitrided bearing of the present embodiment has a chemical composition containing, in mass %, C: 0.22 to 0.45%, Si: not more than 0.50%, Mn: 0.40 to 1.50%, P: not more than 0.015%, S: not more than 0.005%, Cr: 0.30 to 2.0%, Mo: 0.10 to 0.35%, V: 0.20 to 0.40%, Al: 0.005 to 0.10%, N: not more than 0.030%, and O: not more than 0.0015%, with the balance being Fe and impurities, and satisfying Formulae (1) and (2). 1.20<0.4Cr+0.4Mo+4.5V<2.60??(1) 2.7C+0.4Si+Mn+0.8Cr+Mo+V>2.

Abstract: Provided is a carbonitrided bearing part which has high hardenability and toughness, and is excellent in wear resistance and surface-originated flaking life. A carbonitrided bearing part of the present embodiment has a chemical composition containing, in mass %, C: 0.15 to 0.45%, Si: not more than 0.50%, Mn: 0.40 to 1.50%, P: not more than 0.015%, S: not more than 0.005%, Cr: 0.30 to 2.0%, Mo: 0.10 to 0.35%, V: 0.20 to 0.40%, Al: 0.005 to 0.10%, N: not more than 0.030%, and O: not more than 0.0015%, with the balance being Fe and impurities, and satisfying Formulae (1) and (2). At surface, C concentration is 0.7 to 1.2%, N concentration is 0.15 to 0.6%, and Rockwell hardness HRC is 58 to 65. 1.20<0.4Cr+0.4Mo+4.5V<2.60??(1) 2.7C+0.4Si+Mn+0.8Cr+Mo+V>2.

Abstract: A wire material used for manufacturing a non-heat treated component whose tensile strength is 900 MPa to 1300 MPa, containing, in mass %: C: 0.20% to 0.50%, Si: 0.05% to 2.0%, Mn: 0.20% to 1.0%, being limited to contain P: 0.030% or less, S: 0.030% or less, N: 0.005% or less, F1 defined by the following expression (1) is less than 0.60, with the balance made up of Fe and inevitable impurities, wherein a metal structure contains a pearlite structure of 64×(C %)+52% or more in a volume fraction, with the balance made up of one kind or two kinds of a pro-eutectoid ferrite structure and a bainite structure, an average block grain diameter of the pearlite structure at a region from a surface layer to 0.1 D is 15 ?m or less when a diameter of the wire material is set to be D, and (the average block grain diameter of the pearlite structure at the region from the surface layer to 0.1 D)/(an average block grain diameter of the pearlite structure at a range from 0.25 D to a center) is less than 1.0.

Abstract: According to an aspect of the present invention, there is provided a steel containing, by mass %, C: 0.08% to 0.12%, Si: 0.05% to 0.50%, Mn: 1.00% to 3.00%, P: 0.040% or less, S: 0.020% or less, Cr: 1.0% to 2.5%, Cu: 0.01% to 0.50%, Ni: 0.75% to 3.20%, Mo: 0.10% to 0.50%, Nb: 0.005% to 0.050%, Al: 0.010% to 0.100%, N: 0.0050% to 0.0150%, V: 0% to 0.300%, Ca: 0% to 0.0100%, Zr: 0% to 0.0100%, Mg: 0% to 0.0100%, and a remainder including Fe and impurities, in which a number density of Mn sulfides having an equivalent circle diameter of more than 5 m is 0 pieces/mm2 to 10 pieces/mm2, and an average aspect ratio of the Mn sulfides having an equivalent circle diameter of 1.0 m to 5.0 ?m is 1.0 or more and 10.0 or less.

Abstract: Provided is a steel for carbonitrided bearing which excels in hardenability and also excels in toughness, wear resistance, and surface-originated flaking life after quenching and tempering. A steel for carbonitrided bearing of the present embodiment has a chemical composition containing, in mass %, C: 0.22 to 0.45%, Si: not more than 0.50%, Mn: 0.40 to 1.50%, P: not more than 0.015%, S: not more than 0.005%, Cr: 0.30 to 2.0%, Mo: 0.10 to 0.35%, V: 0.20 to 0.40%, Al: 0.005 to 0.10%, N: not more than 0.030%, and O: not more than 0.0015%, with the balance being Fe and impurities, and satisfying Formulae (1) and (2). 1.20<0.4Cr+0.4Mo+4.5V<2.60??(1) 2.7C+0.4Si+Mn+0.8Cr+Mo+V>2.

Abstract: Provided is a carbonitrided bearing part which has high hardenability and toughness, and is excellent in wear resistance and surface-originated flaking life. A carbonitrided bearing part of the present embodiment has a chemical composition containing, in mass %, C: 0.15 to 0.45%, Si: not more than 0.50%, Mn: 0.40 to 1.50%, P: not more than 0.015%, S: not more than 0.005%, Cr: 0.30 to 2.0%, Mo: 0.10 to 0.35%, V: 0.20 to 0.40%, Al: 0.005 to 0.10%, N: not more than 0.030%, and O: not more than 0.0015%, with the balance being Fe and impurities, and satisfying Formulae (1) and (2). At surface, C concentration is 0.7 to 1.2%, N concentration is 0.15 to 0.6%, and Rockwell hardness HRC is 58 to 65. 1.20<0.4Cr+0.4Mo+4.5V<2.60??(1) 2.7C+0.4Si+Mn+0.8Cr+Mo+V>2.

Abstract: A steel wire rod or steel bar as hot-rolled, including: by mass %: C: 0.1 to 0.6%, Si: 0.01 to 1.5%, Mn: 0.05 to 2.5%, Al: 0.015 to 0.3%, and N: 0.0040 to 0.0150%, and P: limited to 0.035% or less and S: limited to 0.025% or less, and the balance substantially consisting of iron and unavoidable impurities, wherein a depth of d (mm) from the surface of the surface layer region with 20 HV 0.2 or more higher, relative to HV 0.2 that is the average hardness in the region where the depth from the surface is from sectional radius R×0.5 (mm) to the center satisfies the formula (1); the steel structure of the surface layer region has a ferrite fraction of 10% or less by area ratio, with the balance being one or two or more of martensite, bainite and pearlite; the steel structure where the depth from the surface is from the sectional radius R×0.

Abstract: A steel wire rod which is a material of steel wires includes, as a metallographic structure, by area %, 95% to 100% of a pearlite, wherein an average pearlite block size at a central portion of the steel wire rod is 1 ?m to 25 ?m, an average pearlite block size at a surface layer portion of the steel wire rod is 1 ?m to 20 ?m, and, when a minimum lamellar spacing of the pearlite at the central portion of the steel wire rod is S in unit of nm and when a distance from a peripheral surface of the steel wire rod to a center is r in unit of mm, S<12r+65 is satisfied.

Abstract: Disclosed is a high-strength Zn—Al coated steel wire for bridges with excellent corrosion resistance and fatigue properties, the Zn—Al coated steel wire includes: a steel wire; and a Zn—Al coating having a coating body layer and an Fe—Al alloy layer formed in an interface between a surface layer of the steel wire and the coating body layer, wherein a chemical composition of a core material of the steel wire includes, by mass %: C: 0.70% to 1.2%; Si: 0.01% to 2.5%; Mn: 0.01% to 0.9%; P: limited to 0.02% or less; S: limited to 0.02% or less; N: limited to 0.01% or less; and the balance including Fe and unavoidable impurities, wherein wire-drawn pearlite is most abundant microstructure among microstructures of the core material of the steel wire; wherein an average composition of the Zn—Al coating includes, by mass %, Al: 3.0 to 15.0%; and Fe: limited to 3.0% or less, and wherein the Fe—Al alloy layer has a thickness of 5 ?m or less.

Abstract: The present invention provides a hydrate of N-[(4S)-2-amino-2?,2?-dimethyldispiro[1,3-oxazole-4,4?-chromene-3?,3?-oxetan]-6?-yl]-5-chloropyridine-2-carboxamide which is useful as an active ingredient of a pharmaceutical composition, in particular, a pharmaceutical composition for preventing or treating diseases or conditions associated with and/or mediated by ?-secretase activity, hydrolysis of a ?-secretase site of a ?-amyloid precursor protein, and/or ?-amyloid protein accumulation, including a pharmaceutical composition for preventing or treating diseases including, but not limited to, Glaucoma, MCI (Mild cognitive impairment) or Alzheimer's disease, especially, Alzheimer's disease.

Abstract: The present invention provides a wire rod with a composition at least including: C: 0.95-1.30 mass %; Si: 0.1-1.5 mass %; Mn: 0.1-1.0 mass %; Al: 0-0.1 mass %; Ti: 0-0.1 mass %; P: 0-0.02 mass %; S: 0-0.02 mass %; N: 10-50 ppm; O: 10-40 ppm; and a balance including Fe and inevitable impurities, wherein 97% or more of an area in a cross-section perpendicular to the longitudinal direction of the wire rod is occupied by a pearlite, and 0.5% or less of an area in a central area in the cross-section and 0.5% or less of an area in a first surface layer area in the cross-section are occupied by a pro-eutectoid cementite.

Abstract: The present invention inexpensively provides with high productivity and good yield a steel rod superior in drawability and a steel wire superior in twistability using the same as a material, that is, draws a high strength steel rod superior in ductility where the chemical components contain C: 0.80 to 1.20%, Si: 0.1 to 1.5%, Mn: 0.1 to 1.0%, Al: 0.01% or less, Ti: 0.01% or less, one or both of W: 0.005 to 0.2% and Mo: 0.003 to 0.2%, N: 10 to 30 ppm, B: 4 to 30 ppm (of which, solute B is 3 ppm or more), and O: 10 to 40 ppm, which has a balance of Fe and unavoidable impurities, has an area percentage of pearlite structures of 97% or more, has a balance of non-pearlite structures, and has a total of the area percentage of the non-pearlite structures and the area percentage of the coarse pearlite structures of 15% or less, to obtain high strength steel wire superior in ductility having a tensile strength of 3600 MPa or more and a number density of voids of lengths of 5 ?m or more at the center of 100/mm2 or less.