A high-strength steel wire includes a predetermined chemical composition. In the high-strength steel wire, a metallographic microstructure includes a pearlite structure of not less than 95% by area, an average aspect ratio R of a pearlite block, measured in a surface layer in a cross section in an axial direction including an axis of the steel wire, is 2.0 or more, assuming that a diameter of the steel wire is D, a ratio of an average aspect ratio measured in the surface layer to an average aspect ratio measured at a position of 0.25D is 1.1 or more in the cross section in the axial direction including the axis of the steel wire, and a tensile strength of the steel wire is 1,800 MPa or more.

In a rolled steel bar or rolled wire rod for a cold-forged component having a predetermined chemical composition, Y1 represented by Y1=[Mn][Cr] and Y2 represented by Y2=0.134(D/25.4(0.50[C])/(0.50[C]) satisfy Y1>Y2, the tensile strength is 750 MPa or less, an internal structure is a ferrite-pearlite structure, and the ferrite fraction in the internal structure is 40% or greater.

Provided is a method for manufacturing a magnetostrictive torque sensor shaft mounting a sensor portion of a magnetostrictive torque sensor. The method includes conducting heat treatment on a shaft material including chrome steel or chrome-molybdenum steel by carburizing, quenching and tempering, and conducting shot peening on the shaft material after the heat treatment at least on a position where the sensor portion is to be mounted. The shot peening is conducted by firing shot with a particle size of not less than 0.6 mm and a Rockwell hardness of not less than 60 at a jet pressure of not less than 0.4 MPa for a jet exposure time of not less than 2 minutes.

A steel reinforcing bar contains 0.06 wt % to 0.11 wt % carbon, more than 0 and not more than 0.25 wt % silicon, 0.8 wt % or more and less than 2.0 wt % manganese, more than 0 and not more than 0.01 wt % phosphorus, more than 0 and not more than 0.01 wt % sulfur, 0.01 to 0.03 wt % aluminum, 0.50 to 1.00 wt % nickel, 0.027 to 0.125 wt % molybdenum, more than 0 and not more than 0.25 wt % chromium, more than 0 and not more than 0.28 wt % copper, more than 0 and not more than 0.01 wt % nitrogen, and the remainder being iron and unavoidable impurities. The reinforcing bar has a surface layer and a core. The surface layer has a hardened layer of tempered martensite, and the core has a mixed structure of bainite, ferrite and pearlite.

A soft magnetic alloy is provided. The alloy consists essentially of 5 wt %Co25 wt %, 0.3 wt %V5.0 wt %, 0 wt %Cr3.0 wt %, 0 wt %Si3.0 wt %, 0 wt %Mn3.0 wt %, 0 wt %Al3.0 wt %, 0 wt %Ta0.5 wt %, 0 wt %Ni0.5 wt %, 0 wt %Mo0.5 wt %, 0 wt %Cu0.2 wt %, 0 wt %Nb0.25 wt % and up to 0.2 wt % impurities.

This invention provides a high-strength PC steel wire having a chemical composition containing, in mass %, C: 0.90 to 1.10%, Si: 0.80 to 1.50%, Mn: 0.30 to 0.70%, P: 0.030% or less, S: 0.030% or less, Al: 0.010 to 0.070%, N: 0.0010 to 0.010%, Cr: 0 to 0.50%, V: 0 to 0.10%, B: 0 to 0.005%, Ni: 0 to 1.0%, Cu: 0 to 0.50%, and the balance: Fe and impurities. A ratio between the Vickers hardness (Hv.sub.S) at a location (surface layer) that is 0.1D [D: diameter of steel wire] from the surface of the steel wire and the Vickers hardness (Hv.sub.I) of a region on the inner side relative to the surface layer satisfies the formula [1.10<Hv.sub.S/Hv.sub.I1.15]. An average carbon concentration in a region from the surface to a depth of 10 m (outermost layer region) of the steel wire is 0.8 times or less a carbon concentration of the steel wire. The steel micro-structure in the region on the inner side relative to the outermost layer region contains, in area %, a pearlite structure: 95% or more. The tensile strength of the steel wire is 2000 to 2400 MPa. The method of producing this high-strength PC steel wire is simple, and the high-strength PC steel wire is excellent in delayed fracture resistance characteristics.

A coated steel substrate including a coating including nanographite having a lateral size between 1 and 60 m and a binder, wherein the steel substrate has the following compositions in weight percent: 0.31C1.2%, 0.1Si1.7%, 0.7Mn3.0%, P0.01%, S0.1%, Cr0.5%, Ni0.5%, Mo0.1%, and on a purely optional basis, one or more elements such as Nb0.05%, B0.003%, Ti0.06%, Cu0.1%, Co0.1%, N0.01%, V0.05%, the remainder of the composition being made of iron and inevitable impurities resulting from the elaboration; and a method for the manufacture of the coated steel substrate.

A steel wire has a microstructure that is completely ferritic, a mixture of ferrite and cementite or a mixture of ferrite and pearlite and has a weight content of carbon C such that C<0.05% and a weight content of chromium Cr such that Cr<12%. The process for drawing the wire comprises: at least one first uninterrupted series of steps of drawing the wire from a diameter D to a diameter d, at least one second uninterrupted series of steps of drawing the wire of diameter d to a diameter d, and one or more intermediate steps between the first and second uninterrupted series of steps of drawing the wire, the wire having a temperature less than or equal to 300 C. during the or each intermediate step.

A steel bar having yield strength of 700 MPa class, excellent yield ratio, and excellent uniform elongation property is provided. The steel bar includes bainite and ferrite included in a center of the steel bar and bainite accounts for 20 to 80% by volume.

This invention provides a high-strength PC steel wire having a chemical composition containing, in mass %, C: 0.90 to 1.10%, Si: 0.80 to 1.50%, Mn: 0.30 to 0.70%, P: 0.030% or less, S: 0.030% or less, Al: 0.010 to 0.070%, N: 0.0010 to 0.010%, Cr: 0 to 0.50%, V: 0 to 0.10%, B: 0 to 0.005%, Ni: 0 to 1.0%, Cu: 0 to 0.50%, and the balance: Fe and impurities. A ratio between the Vickers hardness (Hv.sub.S) at a location (surface layer) that is 0.1D [D: diameter of steel wire] from the surface of the steel wire and the Vickers hardness (Hv.sub.I) of a region on the inner side relative to the surface layer satisfies the formula [1.10<Hv.sub.S/Hv.sub.I1.15]. The steel micro-structure in the region from the surface of the steel wire to 0.01D (outermost layer region) consists of, in area %, a pearlite structure: less than 80%, and the balance: a ferrite structure and/or a bainitic structure. The steel micro-structure in the region on the inner side relative to the outermost layer region contains, in area %, a pearlite structure: 95% or more. The tensile strength of the steel wire is 2000 to 2400 MPa. The method of producing this high-strength PC steel wire is simple, and the high-strength PC steel wire is excellent in delayed fracture resistance characteristics.