Abstract: The present invention has as its object the provision of a steel member and steel sheet having high tensile strength and toughness and excellent in hydrogen embrittlement resistance in a corrosive environment and methods for manufacturing the same. The steel member of the present invention has predetermined chemical constituents and has a maximum value of content of Cu in a range from the surface to a depth of 0 to 30 ?m of 1.4 times the content of Cu at a depth of 200 ?m.

Abstract: An apparatus and a method for rapidly heating cold-rolled strip steel (10). The apparatus for rapidly heating cold-rolled strip steel (10) comprises a heating zone, a soaking zone, and a cooling zone, and the heating zone is sequentially divided into a first heating section (1), a second heating section (2), a third heating section (3), and a fourth heating section (4) along a moving direction of the strip steel (10) to be heated, the first heating section (1) and the fourth heating section (4) being radiant heating sections, and the second heating section (2) and the third heating section (3) being inductive heating sections. The method for rapidly heating cold-rolled strip steel (10) uses the apparatus for rapidly heating cold-rolled strip steel (10) to heat the strip steel (10).

Abstract: A cold rolled steel sheet of the present invention has a specific chemical composition and a steel microstructure in which the average aspect ratio of ferrite crystal grains is 2.0 or less; an rave value that is the average value of values obtained by measuring the r-value represented by a first predetermined formula in three places apart with spacings of 200 mm in the sheet width direction is 1.20 or more, and |?rave| that is the average value of values obtained by measuring, in three places apart with spacings of 200 mm in the sheet width direction, |?r| that is the absolute value of ?r represented by a second predetermined formula is 0.40 or less and the difference between the largest value and the smallest value of |?r| among the three places is 0.15 or less.

Abstract: Provided are a high-strength steel sheet having a yield strength of 550 MPa or more and excellent fatigue-strength of a weld and a method for manufacturing the steel sheet. A high-strength steel sheet has a specified chemical composition, a steel microstructure observed in a cross section in a thickness direction parallel to a rolling direction including 40% to 75% of a martensite phase in terms of volume fraction, in which a total volume fraction of martensite grains whose average grain diameter ratios with respect to adjacent ferrite grains are ¼ or more and 1 or less is 60% or more with respect to an entire martensite phase, and a yield strength (YP) of 550 MPa or more.

Abstract: Provided is a steel sheet for a hot press formed member having excellent resistance to hydrogen delayed fracture, and a method for manufacturing the same. A steel sheet for a hot press formed member comprises: a base steel sheet; an aluminum alloy plating layer on a surface of the base steel sheet; and an oxide layer which is formed on a surface of the plating layer and has a thickness of 0.05 ?m or more.

Abstract: There is provided a hot-rolled steel sheet suitable for manufacturing an electric resistance welded steel tube, having workability necessary for roll forming and high yield strength, for coiled tubing without performing whole-tube quenching treatment and reheating-tempering treatment after electric resistance welding. The steel sheet includes, by mass %, C, Si, Mn, P, S, Al, Cr, Cu, Ni, Mo, Nb, V, Ti, and N contained at a specific content. The steel sheet has a microstructure containing 3% to 20% martensite and 10% or less retained austenite on a volume fraction basis, the remainder being bainite. The yield strength is set to 600 MPa or more, the tensile strength is set to 950 MPa or more, and the uniform elongation is set to 7.0% or more.

Abstract: An austenitic wear-resistant steel plate according to an aspect of the present invention has a predetermined chemical composition, amounts of C and Mn by mass % satisfy ?13.75×C+16.5?Mn??20×C+30, the volume fraction of austenite in a metallographic structure is 40% or more and less than 95%, and the average grain size of the austenite is 40 to 300 ?m.

Abstract: The austenitic stainless steel containing niobium according to an exemplary embodiment of the present invention includes: 16 to 26 wt. % of chromium (Cr), 8 to 22 wt. % of nickel (Ni), 0.02 to 0.1 wt. % of carbon (C), 0.2 to 1 wt. % of niobium (Nb), 0.015 to 0.025 wt. % of titanium (Ti), 0.004 to 0.01 wt. % of nitrogen (N), and 0.5 to 2 wt. % of manganese (Mn), wherein the austenitic stainless steel containing niobium has an austenitic matrix structure, a fine niobium carbide and a fine titanium nitride are precipitated in the austenitic matrix structure, and the fine niobium carbide is uniformly dispersed in the austenitic matrix structure.

Abstract: A method for producing a steel strip with an aluminium alloy coating layer in a continuous coating process. Also, a steel strip coated with an aluminium alloy coating layer that can be produced in accordance with the method, the use of such a coated steel strip and the product made by using the coated steel strip.

Abstract: Steel for a crankshaft includes 0.37 to 0.42 wt % of carbon (C), 0.55 to 0.70 wt % of silicon (Si), 1.45 to 1.65 wt % of manganese (Mn), 0.025 wt % or less (excluding 0 wt %) of phosphorus (P), 0.020 to 0.035 wt % of sulfur (S), 0.15 to 0.30 wt % of chromium (Cr), 0.035 to 0.055% of vanadium (V), and the remainder of Fe and other inevitable impurities. The steel for a crankshaft has strength that is maintained high even when reducing the amount of vanadium.

Abstract: A hot dipped medium manganese steel and a manufacturing method therefor. The medium manganese steel comprises a steel base plate and a coating on the surface of the steel base plate; the mass percentages of the components in the hot dipped medium manganese steel are: C: 0.1 to 0.3%, Si: 0.1 to 2.0%, Mn: 5 to 12%, Al: 1 to 2%, P?0.02%, S?0.02%, N?0.005%, and the remaining being Fe and unavoidable impurities; the core structure is ferrite and austenite, and the surface layer of the steel base plate is a ferrite layer.

Abstract: The present invention belongs to the technical field of alloy materials, and particularly relates to high pressure and corrosion resistant steel and a preparation method and an application thereof. The high pressure and corrosion resistant steel provided by the present invention has a tensile strength of 1,020-1,100 MPa, a yield strength of 980-1,050 MPa, an elongation of 20%-22%, a reduction of area of 60%-80%, and impact energy of more than 100 J at a low temperature of 40° C., and has excellent high pressure and corrosion resistance.

Abstract: A steel alloy including, by weight percent: Ni: 18 to 19%; Co: 11.5 to 12.5%; Mo: 4.6 to 5.2%; Ti: 1.3 to 1.6%; Al: 0.05 to 0.15%; Nb: 0.15 to 0.30%; B: 0.003 to 0.020%; Cr: max 0.25%; Mn: max 0.1%; Si: max 0.1%; C: max 0.03%; P: max 0.005%; and S: max 0.002%, the balance being iron plus incidental impurities.

Abstract: According to the disclosure, it is possible to increase the magnetic flux density and reduce iron loss by setting a chemical composition containing, by mass %, C: 0.0050% or less, Si: 1.50% or more and 4.00% or less, Al: 0.500% or less, Mn: 0.10% or more and 5.00% or less, S: 0.0200% or less, P: 0.200% or less, N: 0.0050% or less, O: 0.0200% or less, and at least one of Sb: 0.0010% or more and 0.10% or less, and Sn: 0.0010% or more and 0.10% or less, with the balance being Fe and inevitable impurities, an Ar3 transformation temperature of 700° C. or higher, a grain size of 80 ?m or more and 200 ?m or less, and a Vickers hardness of 140 HV or more and 230 HV or less.

Abstract: For the purpose of providing a method of die cast product of spheroidal graphite cast iron and a die cast product of spheroidal graphite cast iron having the number of spherical graphites of 3000/mm2 or more in an as cast state, there is disclosed a method of die cast product of ultrafine spheroidal graphite cast iron, including the steps of: a melting step of heating and melting raw materials made of cast iron to obtain source melting metal; a spheroidizing treatment step in which a spheroidizing treatment is performed; an inoculation step of inoculating; and a casting step of casting in a die mold. The amount of nitrogen is adjusted so that the amount of nitrogen generated in the time of melting becomes 0.9 ppm (mass) or less.

Abstract: A steel alloy workpiece and a method for making a press-hardened steel (PHS) component using the steel alloy workpiece is provided. The steel alloy workpiece includes between about 1.0 and 5.0 weight percent chromium, between about 0.5 and 2.0 weight percent silicon, and a surface having a predetermined imprinted pattern. The imprinted pattern includes one of a plurality of overlapping nested sinusoidal waves and a honey-comb pattern, and ascribes a surface roughness of between about 1.0 microns and 2.5 microns. The method includes providing the steel alloy workpiece, heating the workpieces at a predetermined time and temperature, hot stamping the workpieces into the PHS component, quenching the PHS component at a predetermined quench rate, and e-coating the PHS component. The e-coating is applied directly onto the surface of the PHS component.

Abstract: An embodiment of the present invention provides a non-oriented electrical steel sheet, including Si at 2.0 to 4.0 wt %, Al at 1.5 wt % or less (excluding 0 wt %), Mn at 1.5 wt % or less (excluding 0 wt %), Cr at 0.01 to 0.5 wt %, V at 0.0080 to 0.015 wt %, C at 0.015 wt % or less (excluding 0 wt %), N at 0.015 wt % or less (excluding 0 wt %), and the remainder including Fe and other impurities unavoidably added thereto. 0.004?([C]+[N])?0.022??[Equation 1] (In Equation 1, [C] and [N] represent a content (wt %) of C and N, respectively.

Abstract: A method for manufacturing a high-strength galvanized steel sheet having excellent strength-elongation balance, coating adhesiveness, and surface appearance. The method includes: (i) a first heating process of heating a steel sheet having a predetermined chemical composition, (ii) a first pickling process of pickling the steel sheet which was subjected to the first heating process in an oxidizing acidic aqueous solution, (iii) a second pickling process of pickling the steel sheet which was subjected to the first pickling process in a non-oxidizing acidic aqueous solution, (iv) a second heating process of holding the steel sheet, which was subjected to the second pickling process, at a temperature range of 700° C. or higher and 900° C. or lower in a hydrogen-containing atmosphere for 20 seconds or more and 300 seconds or less, and (v) performing a galvanizing treatment on the steel sheet which was subjected to the second heating process.

Abstract: There is provided a sintered bearing having high rotational accuracy and low rotational fluctuation. This bearing includes a bearing surface (4a), and is made of a sintered compact (4?) produced by molding and sintering a raw material powder (10) containing a partially diffusion-alloyed powder (11) in which a copper powder (13) is partially diffused on a surface of an iron powder (12), a tin powder (14) as a low-melting-point metal powder, and a graphite powder as a solid lubricant powder. The sintered bearing has a radial crushing strength greater than or equal to 300 MPa.

Abstract: An iron-based superalloy for high temperature 700° C. with coherent precipitation of cuboidal B2 nanoparticles, belongs to the field of heat-resistant stainless steel, including Fe, Cr, Ni, Al, Mo, W, Zr, B elements. C, Si, Mn, S, P, O, N are impurity elements. The weight percent (wt. %) of its alloy composition is Cr: 10.0˜12.0, Ni: 13.0˜15.0, Al: 6.0˜7.0, Mo: 2.0˜3.0, W: 0.3˜0.7, Zr: 0.03˜0.05, B: 0.004˜0.007, C?0.02, Si?0.20, Mn?0.20, S?0.01, P?0.02, O?0.005, N?0.02, Fe: balance; and the atomic percent ratio of Zr/B is 1:1, the atomic percent ratio of Cr/(Mo+W) is 8:1, and the atomic percent ratio of Mo/W is 8:1. The coherent precipitation of cuboidal B2 nanoparticles in ferritic matrix through the alloy composition design.