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Jfe Steel Corporation patents (2016 archive)


Recent patent applications related to Jfe Steel Corporation. Jfe Steel Corporation is listed as an Agent/Assignee. Note: Jfe Steel Corporation may have other listings under different names/spellings. We're not affiliated with Jfe Steel Corporation, we're just tracking patents.

ARCHIVE: New 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 | Company Directory "J" | Jfe Steel Corporation-related inventors


Galvanized steel sheet and method for producing the same (as amended)

A method for producing a galvanized steel sheet includes an oxide layer forming step of bringing a galvanized steel sheet into contact with an acidic solution containing sulfate ions, then holding the galvanized steel sheet in contact for 1 to 60 seconds, and then washing the galvanized steel sheet with water; and a neutralization treatment step of holding a surface of an oxide layer, which has been formed in the oxide layer forming step, in contact with an alkaline aqueous solution for 0.5 seconds or longer, and then performing washing with water and drying. The alkaline aqueous solution contains p ions at a p concentration of 0.01 g/l or more and carbonate ions at a carbonate ion concentration of 0.1 g/l or more.. ... Jfe Steel Corporation

High-strength cold-rolled steel sheet and method for manufacturing the same (as amended)

A high-strength cold-rolled steel sheet has a chemical composition containing, by mass %, c: 0.15% or more and 0.30% or less, si: 0.8% or more and 2.4% or less, mn: 2.4% or more and 3.5% or less, p: 0.08% or less, s: 0.005% or less, al: 0.01% or more and 0.08% or less, n: 0.010% or less, ti: 0.002% or more and 0.05% or less, b: 0.0002% or more and 0.0050% or less, and the balance being fe and inevitable impurities, a microstructure including ferrite having an average grain diameter of 3 μm or less and a volume fraction of 5% or less (including 0%), retained austenite having a volume fraction of 10% or more and 20% or less, martensite having an average grain diameter of 4 μm or less and a volume fraction of 20% or less (including 0%), and the balance including bainite and/or tempered martensite.. . ... Jfe Steel Corporation

Material for cold-rolled stainless steel sheet and production method therefor (as amended)

A material for stainless steel cold rolling suitable for producing a cold-rolled stainless steel sheet that has sufficient corrosion resistance and ridging resistance as well as excellent formability and surface properties is provided. The material for stainless steel cold rolling according to the present invention contains, in terms of % by mass, c: 0.007% to 0.05%, si: 0.02% to 0.50%, mn: 0.05% to 1.0%, p: 0.04% or less, s: 0.01% or less, cr: 15.5% to 18.0%, al: 0.001% to 0.10%, n: 0.01% to 0.06%, and the balance being fe and unavoidable impurities, wherein the material has a microstructure that includes 10% to 60% of a martensite phase in terms of area fraction, with the remainder being a ferrite phase, and the martensite phase has a hardness of hv500 or less.. ... Jfe Steel Corporation

Stress corrosion crack test method in alcohol environment

A stress corrosion crack test method for evaluating the stress corrosion crack susceptibility of a steel material in alcohol. The method includes filling a cell containing a uniaxial tensile test piece of the steel material with an alcohol solution containing carboxylic acid: 0.1 mmol/l or more and less than 40 mmol/l, chloride ions: 0.05 mg/l or more and less than 300 mg/l, and water: 0.1 vol. ... Jfe Steel Corporation

Method for controlling dew point of reduction furnace, and reduction furnace

Provided are a method for controlling a dew point in a reducing furnace and a reducing furnace in which, even in the case of galvanizing si-added steel, coating adhesion can be secured, alloying treatment can be performed without increasing the alloying temperature excessively, and it is possible to obtain a hot-dip galvanized steel sheet having an excellent coating appearance. When a steel sheet is subjected to annealing and hot-dip galvanizing treatment using continuous hot-dip galvanizing equipment including at least a radiant tube-type reducing furnace, a mixed gas of a dry gas and a humidified gas by a humidifying device having a water vapor permeable membrane is used as a gas to be supplied into the reducing furnace. ... Jfe Steel Corporation

Steel sheet for crown cap, method for manufacturing same, and crown cap

A steel sheet for crown caps includes c: 0.0005 to 0.0050%, si: 0.020% or less, mn: 0.10 to 0.60%, p: 0.020% or less, s: 0.020% or less, al: 0.01 to 0.10%, n: 0.0050% or less, nb: 0.010 to 0.050%, and fe and inevitable impurities. The steel sheet has an average r value of 1.30 or more and a yp of 450 mpa or more and 650 mpa or less. ... Jfe Steel Corporation

High-strength steel sheet and method of manufacturing the same

A high-strength steel sheet has excellent workability, excellent phosphatability, and excellent corrosion resistance after electrodeposition coating has been performed, even when the contents of si and mn are high. Condition 1 through condition 3 below are used when continuous annealing is performed on a steel sheet. ... Jfe Steel Corporation

Resin-coated metal sheet for container and method for manufacturing the same

Provided is a resin-coated metal sheet for a container having a resin layer (a) having a multi-layer structure containing polyester as a main component on an inner-surface side of the container when the metal sheet is formed into the container. The resin layer (a) contains terephthalic acid in an amount of 85 mol % or more, the resin layer (a) has at least two layers including an uppermost resin layer (a1) which comes into contact with contents and contains wax compounds in an amount of 0.10 mass % or more and 2.0 mass % or less with respect to the uppermost resin layer (a1), with respect to a raman band of 1615 cm−1 determined by performing raman spectroscopy on the uppermost resin layer (a1), the maximum value of the peak intensity ratio (imd/ind) of peak intensity in a longitudinal direction to peak intensity in a thickness direction is 1.0 or more and 4.0 or less, a thickness of the uppermost resin layer (a1) is 0.5 μm or more and 10 μm or less, and a thickness of the resin layer (a) excluding the thickness of the uppermost resin layer (a1) is 5 μm or more and 20 μm or less.. ... Jfe Steel Corporation

Press molding method, manufacturing method for press-molded component, and method for determining preform shape for use in said methods

A method is provided for press forming a product having a shape of a top board portion, a vertical wall portion continuously formed from the top board portion and a flange portion continuously formed from the vertical wall portion at a press process of two or more stages, wherein a convex or concave bead shape is preformed in a position of a flat metal sheet as a raw material corresponding to a neighborhood of a position generating breakage or flange wrinkles when the raw material is formed into a product shape, and thereafter a product shape is press formed from the raw material having the preformed bead shape.. . ... Jfe Steel Corporation

Non-oriented electrical steel sheet having excellent magnetic properties

A non-oriented electrical steel sheet has a high magnetic flux density and a low iron loss contains in terms of mass %, c: not more than 0.010%, si: 1-4%, mn: 0.05-3%, al: not more than 0.004%, n: not more than 0.005%, p: 0.03-0.20%, s: not more than 0.01% and se: not more than 0.002% or contains in terms of mass, c: not more than 0.01%, si: 1-4%, mn: 0.05-3%, al: not more than 0.004%, n: not more than 0.005%, p: 0.03-0.20%, s: not more than 0.01%, se: not more than 0.003% and further contains one or two selected from sn: 0.001-0.1 mass % and sb: 0.001-0.1 mass %.. . ... Jfe Steel Corporation

Abrasion-resistant steel plate and method for manufacturing the same

An abrasion resistant steel plate having excellent low-temperature toughness and excellent cracking resistance in a portion which has been heated to a temperature range in which low-temperature temper embrittlement occurs and a method for manufacturing the steel plate. The steel plate includes a microstructure at positions located at ¼ of the thickness and at ¾ of the thickness including a martensite single phase microstructure having an average prior austenaite grain diameter in the range of 20 μm to 60 μm, or a mixed microstructure of martensite and bainite having a proportion of martensite-austenite constituent of less than 5% in terms of area ratio with respect to the whole microstructure.. ... Jfe Steel Corporation

Method for suppressing rear face oxidation of carbon-containing refractory, lining structure, and carbon-containing refractory

Provided is a method for suppressing rear face oxidation and a lining structure, with which high airtightness and a great effect of suppressing rear face oxidation are obtained. The method for suppressing rear face oxidation of a carbon-containing refractory includes forming an adherent layer on a rear face of a carbon-containing refractory by applying an alkali metal silicate aqueous solution to the rear face and solidifying the alkali metal silicate aqueous solution. ... Jfe Steel Corporation

Cold rolling facility and cold rolling method

A cold rolling facility includes: a heating device; a tandem mill including a plurality of rolling mills; a meandering-amount measuring unit; a meandering-movement correction device; a shape measuring unit; a shape controller configured to control a shape of a steel sheet after being cold-rolled by the rolling mill located on the uppermost stream side; and a controller configured to control operations of the meandering-movement correction device based on a measurement value of a meandering-movement amount of the steel sheet by the meandering-amount measuring unit to control a meandering movement of the steel sheet before being heated, and configured to control operations of the shape controller based on a measurement value of a shape of the steel sheet by the shape measuring unit to control the meandering movement of the steel sheet that is attributed to cold rolling of the steel sheet by the tandem mill.. . ... Jfe Steel Corporation

Threaded joint for tube

A threaded joint is adapted for tubes where the stress or the strain concentration hardly occur at a threaded corner portion of box side even when the threaded joint receives repeated tensile-compressive forces or repeated bending forces. In a radial seal type threaded joint, tensile efficiency te (%) defined by a ratio sc/sp between a cross-sectional area sc, an area of critical cross section (ccs) including a portion where a tensile stress and a strain become the highest in a tube circumferential cross section of a box and a cross-sectional area sp of a tube body satisfies formula te (%)≧2.25×t/ρ+99.9 having a ratio t/ρ between an internal thread height t of the box and a radius of curvature ρ of a corner portion of internally-threaded bottom load surface side.. ... Jfe Steel Corporation

11/17/16 / #20160333439

Ferritic stainless steel and production method therefor

Provided are a ferritic stainless steel and a method for producing the ferritic stainless steel. A ferritic stainless steel of the present invention contains, in terms of % by mass, c: 0.005% to 0.05%, si: 0.02% to 0.50%, mn: 0.05% to 1.0%, p: 0.04% or less, s: 0.01% or less, cr: 15.5% to 18.0%, al: 0.001% to 0.10%, n: 0.01% to 0.06%, v: 0.01% to 0.25%, ti: 0.001% to 0.020%, nb: 0.001% to 0.030%, and the balance being fe and unavoidable impurities, in which v/(ti+nb)≧2.0 is satisfied.. ... Jfe Steel Corporation

11/17/16 / #20160333435

Grain oriented electrical steel sheet and production method therefor

A magnetic domain refining treatment is performed by dividing a surface of a steel sheet into a plurality of regions in a widthwise direction, disposing a laser irradiation apparatus or an electron beam irradiation apparatus in each of the regions, and forming beam-irradiated regions through beam irradiation, wherein beams are irradiated so that a nature of a juncture between beam-irradiated regions satisfies 0≦α≦0.3×a and −1.2×a+0.02×w−0.5×α−6.5≦β≦−0.13×a−200×(1/w)+5.4 when td spacing β at the juncture between the beam-irradiated regions is −3 to 0 mm, whereby a grain oriented electrical steel sheet having an excellent iron loss property is produced in a good productivity.. . ... Jfe Steel Corporation

11/17/16 / #20160332203

Cold rolling apparatus

A cold rolling apparatus includes: a heating device configured to heat a sequentially transferred steel sheet; a cold rolling mill configured to sequentially cold-roll the steel sheet after being heated; a meandering-movement correction device arranged on an upstream side of the heating device in a transfer direction of the steel sheet, and configured to correct a meandering movement of the steel sheet transferred toward the heating device; and a meandering-movement suppression device arranged between the heating device and the cold rolling mill, and configured to suppress a meandering movement of the steel sheet attributed to the cold rolling of the steel sheet by using the cold rolling mill.. . ... Jfe Steel Corporation

11/03/16 / #20160319966

Threaded joint for heavy-walled oil country tubular goods

A threaded joint for heavy-walled oil country tubular goods can both ensure sealability and prevent galling in a state where a high external pressure is also applied to the threaded joint in addition to a high compressive force. A surface of a pin side forming a seal portion and a surface of a box side forming a seal portion are formed into a convex curved surface and a tapered surface, respectively. ... Jfe Steel Corporation

11/03/16 / #20160319390

Method for producing grain-oriented electrical steel sheet

In a method for producing a grain-oriented electrical steel sheet by including a series of steps of hot rolling a raw steel material containing c: 0.002-0.10 mass %, si: 2.0-8.0 mass % and mn: 0.005-1.0 mass % to obtain a hot rolled sheet, subjecting the hot rolled steel sheet after or without hot band annealing to one stage cold rolling or two or more stage cold rollings including an intermediate annealing therebetween to obtain a cold rolled sheet having a final sheet thickness, subjecting the cold rolled sheet to decarburization annealing combined with primary recrystallization annealing, applying an annealing separator to the steel sheet surface, and then subjecting to a final annealing.. . ... Jfe Steel Corporation

11/03/16 / #20160319385

High-strength galvanized steel sheet and method for manufacturing the same

Provided are a high-strength galvanized steel sheet which can preferably be used as a material for automobile parts and a method for manufacturing the steel sheet. The steel sheet has a c content of 0.15% or less, in which an area ratio of ferrite is 10% or less, an area ratio of bainitic ferrite is 2% or more and 30% or less, an area ratio of martensite is 60% or more and 98% or less, an area ratio of retained austenite is less than 2%, an average grain diameter of martensite adjacent to bainite is 15 μm or less, a proportion of massive martensite adjacent only to bainite to the whole metallographic structure is 10% or less, and a value (Δhv) calculated by subtracting the vickers hardness at a position located at 20 μm from the surface of the steel sheet from the vickers hardness at a position located at 100 μm from the surface of the steel sheet is 30 or more.. ... Jfe Steel Corporation

10/27/16 / #20160312329

High-strength steel sheet and method for producing the same (as amended)

Provided are a high-strength steel sheet, which is suitable as a material of automotive parts, and a method for producing the high-strength steel sheet. In the high-strength steel sheet, the c content is 0.15% or less, the area ratio of ferrite is 8% to 45%, the area ratio of martensite is 55% to 85%, the proportion of martensite grains adjacent to only ferrite grains in the entire microstructure is 15% or less, the average crystal grain sizes of ferrite and martensite are each 10 μm or less, and the area ratio of ferrite grains having a size of 10 μm or more to all the ferrite grains included in a portion of the steel sheet which extends from 20 to 100 μm below the surface thereof is less than 5%.. ... Jfe Steel Corporation

10/27/16 / #20160312327

Steel plate and method for manufacturing same (as amended)

A steel plate includes a predetermined chemical composition, in which b is controlled to be less than 0.0003%, and the balance is fe and incidental impurities. The steel plate also includes precipitates containing ti, nb, and mo and having a mean particle size of 20 nm or less, the relationship [nb]/([ti]+[nb]+[mo])≧0.3 being satisfied, where [ti] is the ti content, [nb] is the nb content, and [mo] is the mo content, thereby providing a thick, high tensile strength steel plate that is suitable for use in steel structures such as marine structures, ships, pressure vessels, and penstocks, has a yield stress (ys) of 460 mpa or greater, and has excellent low-temperature toughness of the heat-affected zone in a multilayer weld (ctod property) and excellent strength and toughness after post weld heat treatment (pwht property).. ... Jfe Steel Corporation

10/20/16 / #20160304982

Method for producing high-strength galvannealed steel sheets

. . A method for producing high-strength galvannealed steel sheets having excellent workability and fatigue resistance. The method comprises subjecting a steel sheet to an oxidation treatment, the oxidation treatment including heating the steel sheet in an upstream stage at a temperature in the range of 400° c. ... Jfe Steel Corporation

10/20/16 / #20160303652

Iron powder for dust cores

The present invention provides iron powder for dust cores that has excellent compressibility and low iron loss after formation. In the iron powder for dust cores, si content is 0.01 mass % or less, apparent density is 3.8 g/cm3 or more, the ratio of iron powder particles with a particle size of 45 μm or less is 10 mass % or less, the ratio of iron powder particles with a particle size of over 180 μm and 250 μm or less is less than 30 mass %, the ratio of iron powder particles with a particle size of over 250 μm is 10 mass % or less, and the vickers hardness (test force: 0.245 n) of a powder cross-section is 80 hv or less.. ... Jfe Steel Corporation

10/06/16 / #20160290721

Continuous annealing furnace for annealing steel strip, method for continuously annealing steel strip, continous hot-dip galvanizing facility, and method for manufacturing hot-dip galvanized steel strip

. . . . A continuous annealing furnace for annealing steel strips that is a vertical-type annealing furnace is configured so that part of gas inside the furnace is drawn and introduced to a refiner disposed outside the furnace including an oxygen removing apparatus and a dehumidifying apparatus, oxygen and moisture contained in the gas are removed to lower the dew point of the gas, and the gas having a lowered dew point is put back into the furnace. At least one gas inlet through which gas is drawn from the furnace into the refiner is disposed in the vicinity of the entry side of the furnace at a distance of 6 m or less in the vertical direction and 3 m or less in the furnace-length direction from the steel-strip-introduction section located at the lower part of the heating zone.. ... Jfe Steel Corporation

10/06/16 / #20160289841

Method of manufacturing a steel sheet for containers

A manufacturing method for steel sheets for containers produces steel sheets with excellent film adhesion qualities. This steel sheet for containers has, on a steel sheet, a chemical conversion coating with a metal zr content of 1-100 mg/m2, a p content of 0.1-50 mg/m2, and an f content of no more than 0.1 mg/m2, upon which is formed a phenolic resin layer with a c content of 0.1-50 mg/m2. ... Jfe Steel Corporation

10/06/16 / #20160289788

Hot-rolled steel sheet and method of manufacturing the same

A hot-rolled steel sheet has a chemical composition containing, by mass %, c: 0.030% or more and 0.120% or less, si: 0.05% or more and 0.50% or less, mn: 1.00% or more and 2.20% or less, p: 0.025% or less, s: 0.0050% or less, n: 0.0060% or less, al: 0.005% or more and 0.100% or less, nb: 0.020% or more and 0.100% or less, mo: 0.05% or more and 0.50% or less, ti: 0.001% or more and 0.100% or less, cr: 0.05% or more and 0.50% or less, ca: 0.0005% or more and 0.0050% or less, and the balance being fe and inevitable impurities, and has a microstructure including bainitic ferrite as a main phase and martensite and retained austenite as second phases, wherein a volume fraction of the main phase is 90% or more, an average grain diameter of the main phase is 10 μm or less, a volume fraction of the martensite is 0.5% or more and 9.5% or less, and a volume fraction of the retained austenite is 0.5% or more and 9.5% or less, wherein the steel sheet has a yield ratio of 90% or less, a yield strength of 555 mpa or more, and a tensile strength of 650 mpa or more.. . ... Jfe Steel Corporation

10/06/16 / #20160289784

High-strength steel sheet and method for manufacturing the same

A high-strength steel sheet and a method for manufacturing a high-strength steel sheet having excellent phosphatability and excellent corrosion resistance after electrodeposition coating has been performed, even in the case where the contents of si and mn are high. The method may comprise annealing a steal sheet by using a continuous annealing method, performing a heating process, controlling the maximum end-point temperature of a steel sheet in the annealing furnace, controlling the traveling time of the steel sheet, and controlling the dew point of the atmosphere.. ... Jfe Steel Corporation

09/29/16 / #20160281189

Stainless steel sheet

A stainless steel sheet having excellent formability which makes it possible to manufacture brake disks for automobiles by performing severe forming. The stainless steel sheet having a chemical composition comprising, by mass %, c: 0.015% or more and less than 0.100%, si: 0.01% or more and 1.00% or less, mn: 0.01% or more and 2.00% or less, p: 0.040% or less, s: 0.030% or less, cr: 10.0% or more and less than 14.0%, ni: 0.01% or more and 0.70% or less, al: 0.001% or more and 0.200% or less, n: 0.005% or more and 0.080% or less, o: 0.0060% or less, b: 0.0002% or more and 0.0030% or less, v: (10×b content (%))% or more and 0.300% or less, and fe and unavoidable impurities as a balance.. ... Jfe Steel Corporation

09/22/16 / #20160276081

Grain oriented electrical steel sheet and method for manufacturing the same

A method of manufacturing a grain oriented electrical steel sheet includes a rolling a slab for a grain oriented electrical steel sheet to obtain a steel sheet having final sheet thickness; subjecting the steel sheet to decarburizing annealing; coating a surface of the steel sheet with annealing separator mainly composed of mgo; subjecting the steel sheet thus coated to final annealing; providing a tension coating to the steel sheet; and subjecting the steel sheet to magnetic domain refinement by laser irradiation after either the final annealing or provision of the tension coating, wherein (1) the coating weight of the anneal separator is at least 10.0 g/m2; (2) coiling tension at which the steel sheet is coiled after being coated with the annealing separator is 30 n/mm2 to 150 n/mm2; and (3) the average cooling rate in cooling process of the final annealing down to 700° c. Is 50° c./hour or less.. ... Jfe Steel Corporation

09/22/16 / #20160271720

Resistance spot welding method

In a resistance spot welding method, test welding and actual welding in which a current pattern is divided into two or more steps are performed. In the test welding, a constant current of a different value is passed in each step, and a time variation of an instantaneous amount of heat generated per unit volume and a cumulative amount of heat generated per unit volume are stored as a target value. ... Jfe Steel Corporation

09/22/16 / #20160271719

Resistance spot welding method

Resistance spot welding is performed on a combination of overlapping steel sheets including at least one steel sheet that has, on a surface thereof, a coated layer with zinc as a main component, by (1) starting electric current passage in a state satisfying 0.9×t≦l≦1.1×t; and (2) dividing electric current into main current and initial current that precedes the main current and is two-step current, setting a current value i1 during current in a first step of the initial current to satisfy im×1.1≦i1≦15.0 ka with respect to a current value in, during the main current, and setting a current value i2 in the subsequent second step to no current or low current satisfying 0≦i2≦im×0.7.. . ... Jfe Steel Corporation

09/15/16 / #20160265079

Continuous annealing system and continuous annealing method

. . . . A continuous annealing system and a continuous annealing method with which it is possible to achieve an annealing atmosphere having a low dew point which is suitable for annealing a steel strip containing easily oxidizable metals such as si and mn at low cost and with stability by preventing easily oxidizable metals such as si and mn in steel from being concentrated in a surface portion of a steel strip and preventing the formation of oxides of easily oxidizable metals such as si and mn.. . ... Jfe Steel Corporation

09/15/16 / #20160265076

Equipment line for manufacturing seamless steel tube or pipe and method of manufacturing high-strength stainless steel seamless tube or pipe for oil wells using the equipment line

An equipment line for manufacturing a seamless steel tube includes a steel heating device, a piercing device that pierces the steel into a hollow steel tube, a rolling mill that forms the hollow steel tube into a seamless steel tube having a predetermined shape, and a cooling system arranged between the heating device and the piercing device or between the piercing device and the rolling mill.. . ... Jfe Steel Corporation

09/08/16 / #20160260531

Grain-oriented electrical steel sheet having excellent magnetic characteristics and coating adhesion

There is provided a grain-oriented electrical steel sheet stably having excellent magnetic characteristics and coating adhesion even when a rapid heating is conducted in a primary recrystallization annealing (decarburization annealing). Concretely, it is a grain-oriented electrical steel sheet provided on its sheet surface with a tension-applying type insulation coating constituted with a coating layer a formed on a steel sheet side and mainly composed of an oxide and a coating layer b formed on a surface side and mainly composed of glass, characterized in that a ratio r (σb/σa) of a tension σb of the coating layer b on the surface side applied to the steel sheet to a tension σa of the coating layer on the steel sheet side a applied to the steel sheet is within a range of 1.20-4.0.. ... Jfe Steel Corporation

09/08/16 / #20160258032

High-strength hot-rolled steel sheet and method for producing the same

A steel slab having a composition containing c: more than 0.07% and 0.2% or less, si: 2.0% or less, mn: 1.0% to 3.0%, al: 0.1% or less, ti: 0.05% to 0.3%, and v: 0.05% to 0.3% on a mass percent basis is heated to 1100° c. Or more and is subjected to rough rolling and finish rolling. ... Jfe Steel Corporation

09/08/16 / #20160257099

Laminated metal sheet for containers, method for producing metal can, and method for evaluating formability of metal sheet (as amended)

Provided are a laminated metal sheet for containers that has excellent formability after heat treatment performed after coating, printing, etc. And is suitable for dr cans, a method for producing a metal can using the above metal sheet and a method for evaluating the formability of a metal sheet. ... Jfe Steel Corporation

09/01/16 / #20160250709

Indirect spot welding apparatus

In the indirect spot welding apparatus, a lower limit in a stable pressing force region where the pressing force of the spot welding electrode against the metal sheets can be controlled within a tolerance of ±10% ranges from 70 n to 200 n and an upper limit in the stable pressing force region ranges from 800 n to 2000 n, and an overshoot os(%)=(pl−al)/al×100 of the pressing force occurring when the spot welding electrode is pressed against the metal sheets is controlled to be 10% or less.. . ... Jfe Steel Corporation

08/25/16 / #20160244866

Steel material having excellent alcohol-induced pitting corrosion resistance and alcohol-induced scc resistance

A steel material of the disclosure has a chemical composition containing, in mass %: 0.03% to 0.3% c; 0.03% to 1.0% si; 0.1% to 2.0% mn; 0.003% to 0.03% p; 0.005% or less s; 0.005% to 0.1% al; 0.005% to 0.5% cu; 0.01% to 0.5% sb; and 0.005% to 0.5% ni, with a balance being fe and incidental impurities. Thus, the steel material has excellent alcohol-induced pitting corrosion resistance and alcohol-induced scc resistance, and can be used for large structures with no need for coating, inhibitor addition, or the like by improving the pitting corrosion resistance and scc resistance of the steel material itself.. ... Jfe Steel Corporation

08/25/16 / #20160243604

Method of sheet forming

A method of sheet forming manufactures a sheet-formed part that is formed in an l-shape as viewed in a plan view and includes a top portion, side wall portions formed on the respective both sides of the top portion, and flange portions contiguously formed with the respective side wall portions, by sheet-forming a metal sheet with the a sheet forming tool. The method includes: a first sheet forming process in which the metal sheet is arranged on a first sheet forming tool including a first punch, a first die, a first blank holder, and a pad; and a second sheet forming process in which the first sheet-formed part formed is sheet-formed into a second sheet-formed part having a top portion and a side wall portion whose shapes are identical with those of the sheet-formed part, with a second sheet forming tool having a second punch and a second die.. ... Jfe Steel Corporation

08/25/16 / #20160243603

Method of producing polygonal closed cross-section structural component with a curved form and polygonal closed cross-section structural component produced by the method

A method of producing a polygonal closed cross-section structural component includes press-forming a metal sheet into a gutter-shaped pre-processed part with a curved form along its longitudinal direction having plural ridge lines corresponding to corner portions of the polygonal closed cross-section in a cross-sectional form developed by cutting the component at a position corresponding to the ridge line located at the innermost side in the radial direction to provide a flange portion extending along the ridge line at the resulting respective ends, and press-forming the pre-processed part to deform inwardly in the cross-sectional direction at a position of one or more of the plural ridge lines to butt the ridge lines located at the innermost side and the flange portions to each other.. . ... Jfe Steel Corporation

08/18/16 / #20160240866

Stainless steel foil for separators of polymer electrolyte fuel cells

The surface of a substrate made of stainless steel foil is coated with a sn alloy layer, with a strike layer in between. The coating weight of the strike layer is 0.001 g/m2 to 1 g/m2.. ... Jfe Steel Corporation

08/18/16 / #20160236294

Resistance spot welding method

Proposed is a resistance spot welding method to join parts to be welded which are a plurality of overlapping metal sheets, including: dividing a current pattern into two or more steps for welding; before actual welding, performing test welding; and subsequently, as actual welding, performing adaptive control welding, in which the two or more steps for welding include a step of securing a current path between the sheets directly below the electrodes and a subsequent step of forming a nugget having a predetermined diameter, and a welding interval time is provided between these steps. This method thus yields a good nugget without causing splashing even under special welding conditions.. ... Jfe Steel Corporation

08/18/16 / #20160236249

Equipment line for manufacturing heavy-walled steel products

An equipment line for manufacturing heavy-walled steel products having excellent low-temperature toughness, the equipment line including a heating device, a cooling device, and a hot working device in this order. The working device includes plurality of hot working devices, and the cooling device is arranged on an entrance side of at least one of the plurality of hot working devices. ... Jfe Steel Corporation

08/11/16 / #20160230259

Hot-dip galvanized steel sheets and galvannealed steel sheets that have good appearance and adhesion to coating and methods for producing the same (as amended)

A hot-dip galvanized steel sheet having a good appearance and good adhesion to a coating, the hot-dip galvanized steel sheet having a composition containing, on a mass basis: c: 0.08% or more and less than 0.20%, si: 0.1% to 3.0%, mn: 0.5% to 3.0%, p: 0.001% to 0.10%, al: 0.01% to 3.00%, and s: 0.200% or less, a remainder being fe and incidental impurities, wherein the hot-dip galvanized steel sheet includes an internal oxidation layer and a decarburized layer, the internal oxidation layer having a thickness of 5 μm or less, the decarburized layer having a thickness of 20 μm or less, and 50% or more by area of the internal oxidation layer is composed of a si oxide containing fe and/or mn represented by fe2xmn2-2xsioy, wherein x ranges from 0 to 1, and y is 3 or 4.. . ... Jfe Steel Corporation

08/11/16 / #20160230240

Grain-oriented electrical steel sheet and method for manufacturing same (as amended)

Provided is a grain-oriented electrical steel sheet including: a forsterite base film formed on a surface of the steel sheet; and an insulating tension coating formed on the base film, in which when ti intensity fx(ti), al intensity fx(al), and fe intensity fx(fe) obtained through quantitative analysis by performing fluorescent x-ray analysis on the surface of the steel sheet satisfy fx(ti)/fx(al)≧0.15 and fx(ti)/fx(fe)≧0.004, the frequency of crystal boundaries of secondary recrystallized grains in the direction orthogonal to the rolling direction is 20 grain boundaries/100 mm or less, the mean thickness of the forsterite base film t(fo) and the thickness of the insulating tension coating t(c) satisfies t(fo)/t(c)≧0.3, and magnetic domain refining treatment is performed by irradiation with a laser beam, plasma flame, or electron beam, a sufficient iron loss reducing effect is achieved in a range where coating detachment does not occur.. . ... Jfe Steel Corporation

08/11/16 / #20160228981

Friction stir welding method for structural steel and method of manufacturing joint for structural steel

A process of pre-heating treatment is performed such that steel sheets or plates as working materials are heated by a heating unit provided ahead of a rotational tool moving in a welding direction to precisely control the surface temperature, area, position and the like of a heating region in the process of pre-heating treatment when performing friction stir welding on structural steel.. . ... Jfe Steel Corporation

08/04/16 / #20160222500

Hot-dip galvanized steel sheets and galvannealed steel sheets that have good appearance and adhesion to coating and methods for producing the same (as amended)

A hot-dip galvanized steel sheet having a good appearance and good adhesion to a coating, the hot-dip galvanized steel sheet having a composition including, on a mass basis: c: 0.20% to 0.50%, si: 0.1% to 3.0%, mn: 0.5% to 3.0%, p: 0.001% to 0.10%, al: 0.01% to 3.00%, and s: 0.200% or less, a remainder being fe and incidental impurities, wherein the hot-dip galvanized steel sheet includes an internal oxidation layer and a decarburized layer, the internal oxidation layer having a thickness of 4 μm or less on a ferrite side from an interface between ferrite and a galvanized layer, the decarburized layer having a thickness of 16 μm or less on the ferrite side from the interface between the ferrite and the galvanized layer, and 50% or more by area of the internal oxidation layer is composed of a si oxide containing fe and/or mn represented by fe2xmn2-2xsioy, wherein x ranges from 0 to 1, and y is 3 or 4.. . ... Jfe Steel Corporation

08/04/16 / #20160221117

Friction stir welding method for steel sheets and method of manufacturing joint

A friction stir welding method for welding steel sheets together includes a heating device disposed ahead of a rotating tool in an advancing direction that preheats an unwelded portion before the welding thereof by the rotating tool and at the time of preheating, the surface temperature distribution in a direction perpendicular to the advancing direction in a position at which the welding by the rotating tool is initiated is set such that given that tac1 is the ac1 point of a steel sheet, the maximum temperature (tu) thereof is 0.6×tac1<tu<1.8×tac1, and given that l is the width of the heating region exceeding a temperature (tl)=0.6×tac1, 0.3×d≦l≦2.0×d is satisfied with a diameter (d) of the shoulder.. . ... Jfe Steel Corporation

07/28/16 / #20160215359

Method of manufacturing a high-strength stainless steel pipe and a high-strength stainless steel pipe

A method of manufacturing a high-strength stainless steel pipe includes forming a steel pipe having a predetermined size, the steel having a composition comprising by mass % 0.005 to 0.05% c, 0.05 to 1.0% si, 0.2 to 1.8% mn, 0.03% or less p, 0.005% or less s, 14 to 20% cr, 1.5 to 10% ni, 1 to 5% mo, 0.5% or less v, 0.15% or less n, 0.01% or less o, 0.002 to 0.1% al, and fe and unavoidable impurities as a balance; applying a quenching treatment two times or more to the steel pipe where the steel pipe is quenched by reheating to a temperature of 750° c. Or above and cooling to a temperature of 100° c. ... Jfe Steel Corporation

07/28/16 / #20160214351

High-strength galvanized steel sheet and method of manufacturing the same

A high-strength galvanized steel sheet includes a base steel sheet having a specific chemical composition and a zinc coating layer disposed on the surface of the base steel sheet in a coating weight per side of 20 g/m2 to 120 g/m2, wherein the amount of hydrogen measured by a specific method is 0.05 mass ppm to 0.40 mass ppm; and isisur/isibulk and imnsur/imnbulk calculated by a specific method are not more than 2.0 and not more than 3.0, respectively.. . ... Jfe Steel Corporation

07/28/16 / #20160214203

Friction stir welding method for steel sheets and method of manufacturing joint

A friction stir welding method for steel sheets includes inserting a rotating tool into an unwelded portion where two or more steel sheets are overlapped or butted together; moving the rotating tool along portions to be welded while rotating the tool so that a softened portion is formed in the steel sheets by friction heat generated between the rotating tool and the steel sheets, and the steel sheets are welded together by utilizing a plastic flow generated by the softened portion being stirred; and preheating the unwelded portion before welding by the rotating tool by a pair of heating devices disposed over and under the unwelded portion and ahead of the rotating tool in the advancing direction to enable high speed welding without the risk of generation of welding defects and damage to the welding tool.. . ... Jfe Steel Corporation

07/28/16 / #20160214171

Alloy steel powder for powder metallurgy and method of producing iron-based sintered body

Provided is an alloy steel powder for powder metallurgy that is capable of achieving both high strength and high toughness in a sintered body using the same. An alloy steel powder for powder metallurgy of this disclosure comprises a composite alloy steel powder and graphite powder. ... Jfe Steel Corporation

07/21/16 / #20160208355

Method of manufacturing hot press formed part, and hot press formed part

. . A method of manufacturing a hot press formed part by hot pressing a coated steel sheet that is obtained by forming a zn-based coating layer on a surface of a steel sheet includes: heating the coated steel sheet to a temperature range of 750° c. Or more and 1000° c. ... Jfe Steel Corporation

07/21/16 / #20160208349

Method for operating a blast furnace

A method for operating a blast furnace that increases combustion temperature and reduces fuel consumption rate is provided. The method includes injecting hot air into the blast furnace from a tuyere. ... Jfe Steel Corporation

07/14/16 / #20160203896

Non-oriented electrical steel sheet having high magnetic flux density and motor

A non-oriented electrical steel sheet having a chemical composition comprising c: not more than 0.010 mass %, si: 1.0-7.0 mass %, mn: 0.001-3.0 mass %, sol. Al: 0.0001-3.5 mass %, p: 0.01-0.2 mass %, s: not more than 0.010 mass %, n: not more than 0.010 mass % and the remainder being fe and inevitable impurities, wherein a ratio (p120/fe700) of a peak-peak height p120 of p near to an electronic energy of 120 ev to a peak-peak height fe700 of fe near to an electronic energy of 700 ev in an auger differential spectrum obtained by analyzing a broken surface of a grain boundary through auger electron spectroscopy is not less than 0.1 and a sheet thickness is 0.10-0.50 mm, and a motor using such a non-oriented electrical steel sheet as an iron core.. ... Jfe Steel Corporation

07/14/16 / #20160203895

Non-oriented electrical steel sheet and hot rolled steel sheet thereof

A non-oriented electrical steel sheet having a high magnetic flux density and a low iron loss at not only a commercial frequency but also a high frequency zone, which has a chemical composition including c: not more than 0.0050 mass %, si: more than 1.5 mass % but not more than 5.0 mass %, mn: not more than 0.10 mass %, sol. Al: not more than 0.0050 mass, p: more than 0.040 mass % but not more than 0.2 mass %, s: not more than 0.0050 mass %, n: not more than 0.0040 mass % and ca: 0.001-0.01 mass % and the remainder being fe and inevitable impurities and a compositional ratio of cao in oxide-based inclusions existing in a steel sheet of not less than 0.4 and/or a compositional ratio of al2o3 of not less than 0.3, and a hot rolled steel sheet used as a raw steel material thereof.. ... Jfe Steel Corporation

07/14/16 / #20160203596

Laser beam welding diagnosis apparatus and laser beam welding diagnosis method

A laser beam welding diagnosis apparatus includes: an imaging unit configured to capture images of a laser beam welding penetration side of a laser beam welded portion at a predetermined time interval; a feature amount calculating unit configured to calculate, from an image captured by the imaging unit, a feature amount of a jetted portion accompanying laser beam welding penetration; a welding diagnosis unit configured to determine that a welding defect in the laser beam welded portion has occurred when values of the feature amounts of a predetermined area around the laser beam welded portion on the laser beam welding penetration side become equal to or less than a predetermined value for a predetermined duration or longer; and an output unit configured to output a welding quality state including the occurrence of the welding defect.. . ... Jfe Steel Corporation

07/07/16 / #20160196909

Method of producing grain oriented electrical steel sheet

Provides is a method of producing a grain oriented electrical steel sheet by heating a steel slab having a predetermined composition, then subjecting the slab to hot rolling to obtain a hot rolled sheet, then optionally subjecting the hot rolled sheet to hot band annealing and subsequent cold rolling once, or twice or more with intermediate annealing performed therebetween to obtain a cold rolled sheet with final sheet thickness, then subjecting the cold rolled sheet to primary recrystallization annealing and subsequent secondary recrystallization annealing, in which the aging index ai of the steel sheet before final cold rolling is set to 70 mpa or less to effectively grow goss-oriented grains to thereby obtain a grain-oriented electrical steel sheet with good magnetic properties, without the restriction of containing a relatively large amount of c.. . ... Jfe Steel Corporation

06/16/16 / #20160168674

Iron-based amorphous alloy thin strip

. . A iron-based amorphous alloy thin strip having a chemical composition represented by a chemical formula of fexbysiz (wherein x is 78-83 at %, y is 8-15 at % and z is 6-13 at %), wherein the number of air pockets at a surface contacting with a cooling roll is not more than 8 pockets/mm2 and an average length in a circumferential direction of the roll is not more than 0.5 mm.. . ... Jfe Steel Corporation

06/16/16 / #20160168656

High-strength cold-rolled steel sheet and method for producing the same

A high-strength cold-rolled steel sheet having excellent elongation, stretch flangeability, and bendability and a method for producing the same.. . ... Jfe Steel Corporation

06/16/16 / #20160167149

Method of cutting and removing adhesive matter at end of cuboid metal material and removal apparatus

Adhesive matter remaining at the end of a cuboid metal material is reliably removed in a relatively short time while suppressing the decrease in yield rate of the metal material. Distances of the upper surface and the lower surface of a cuboid metal material from a reference position are measured using a distance measurement device in the longitudinal direction of the slab including the longitudinal end of the slab. ... Jfe Steel Corporation

06/09/16 / #20160163436

Grain oriented electrical steel sheet and method of manufacturing the same

A grain oriented electrical steel sheet includes forsterite film on a surface of base steel sheet; and an aluminum-concentrated portion in at least one of the forsterite film and an interface between the forsterite film and the base steel sheet by a presence ratio expressed as area-occupying ratio of the al-concentrated portion, of at least 5%, per 10000 μm2 of the surface of the base steel sheet, which has been subjected to magnetic domain refinement treatment by electron beam irradiation.. . ... Jfe Steel Corporation

06/09/16 / #20160160328

Ferritic stainless steel foil

The ferritic stainless steel foil has a composition containing, by mass %, c: 0.050% or less, si: 0.20% or less, mn: 0.20% or less, p: 0.050% or less, s: 0.0050% or less, cr: 10.5% or more and 20.0% or less, ni: 0.01% or more and 1.00% or less, al: more than 1.5% and less than 3.0%, cu: 0.01% or more and 1.00% or less, n: 0.10% or less, and further contains one or more elements selected from ti: 0.01% or more and 1.00% or less, zr: 0.01% or more and 0.20% or less, and hf: 0.01% or more and 0.20% or less, and the balance being fe and inevitable impurities. This enables a composite layer of an al oxide layer and a cr oxide layer to be formed on the surface of the ferritic stainless steel foil in a high-temperature oxidizing atmosphere at 800° c. ... Jfe Steel Corporation

06/09/16 / #20160160311

Method for forming blank and method for determining preforming shape

By using, as a raw material, a thick hot-rolled steel sheet having a chemical composition containing, by mass %, c: 0.02% or more and 0.10% or less, si: 0.05% or more and 0.30% or less, mn: 0.80% or more and 2.00% or less, and nb: 0.010% or more and 0.100% or less and satisfying the condition that a carbon equivalent ceq is 0.25% or more and 0.50% or less, a microstructure including a bainitic ferrite phase and/or a bainite phase, a high strength of 52 ksi or more in terms of yield strength and a high toughness of −45° c. Or lower in terms of fracture transition temperature vtrs, an electric resistance weld zone having a microstructure including a bainitic ferrite phase and/or a bainite phase and satisfying the condition that the ratio of the average crystal grain size of the coarsest-grain portion to the average crystal grain size of the finest-grain portion is 2.0 or less in every portion in the wall thickness direction is obtained.. ... Jfe Steel Corporation

06/09/16 / #20160160310

High-strength galvanized steel sheet having excellent formability and crashworthiness and method for manufacturing the same

A method of manufacturing a galvanized steel sheet having a composition containing, by mass %, c: 0.05% or more and 0.5% or less, si: 0.01% or more and 2.5% or less, mn: 0.5% or more and 3.5% or less, p: 0.003% or more and 0.100% or less, s: 0.02% or less, al: 0.010% or more and 0.5% or less, b: 0.0002% or more and 0.005% or less, ti: 0.05% or less, a relationship of ti>4n being satisfied, and the balance comprising fe and inevitable impurities, and a microstructure containing 60% or more and 95% or less of tempered martensite in terms of area ratio and 5% or more and 20% or less of retained austenite in terms of area ratio. . ... Jfe Steel Corporation

06/09/16 / #20160160308

Steel sheet for can and method for manufacturing the same

A steel sheet exhibiting good drawability and excellent buckling strength of a can body portion against an external pressure, and a method for manufacturing the same. The steel sheet includes c: 0.0030% or more and 0.0100% or less, si: 0.05% or less, mn: 0.10% or more and 1.0% or less, p: 0.030% or less, s: 0.020% or less, al: 0.010% or more and 0.100% or less, n: 0.0050% or less, nb: 0.010% or more and 0.050% or less, and incidental impurities. ... Jfe Steel Corporation

06/09/16 / #20160158822

Hot-pressed member and method of manufacturing the same

Provided is a hot-pressed member excellent in terms of paint adhesiveness and a method of manufacturing the hot-pressed member. A hot-pressed member has a coating layer containing zn and ni on the surface of a steel sheet of which the member is formed, an oxide film containing zn on the coating layer, and a void formation rate is 80% or less for voids formed between the coating layer and the oxide film.. ... Jfe Steel Corporation

06/09/16 / #20160158821

Press forming method and method of manufacturing press-formed part

There is provided a method of manufacturing a curved channel part having a curved portion in a vertical wall portion by press forming, the method restricting stretch flange deformation, which occurs in the vertical wall portion and a flange portion. The method includes a shear deformation step as a step of forming the vertical wall portion. ... Jfe Steel Corporation

06/02/16 / #20160153063

Heavy wall electric resistance welded steel pipe for line pipe and method for manufacturing the same (as amended)

By using, as a raw material, a thick hot-rolled steel sheet having a chemical composition containing, by mass %, c: 0.02% or more and 0.10% or less, si: 0.05% or more and 0.30% or less, mn: 0.80% or more and 2.00% or less, and nb: 0.010% or more and 0.100% or less and satisfying the condition that a carbon equivalent ceq is 0.25% or more and 0.50% or less, a microstructure including a bainitic ferrite phase and/or a bainite phase, a high strength of 52 ksi or more in terms of yield strength and a high toughness of −45° c. Or lower in terms of fracture transition temperature vtrs, and satisfying the condition that the ratio of the average crystal grain size of the coarsest-grain portion to the average crystal grain size of the finest-grain portion is 2.0 or less in every portion in the wall thickness direction is obtained. ... Jfe Steel Corporation

06/02/16 / #20160153062

Method of detecting abnormality at blast furnace and method of operating blast furnace

A method of detecting an abnormality in a blast furnace, wherein the abnormality causes clogging of a tuyere unit of the blast furnace, the method including capturing an image of a raceway unit through an in-furnace monitor window disposed at the tuyere unit; and determining that the abnormality has occurred when a brightness of the captured image is lower than or equal to a predetermined brightness threshold and a rate of decrease in the brightness is lower than or equal to a predetermined brightness-decrease-rate threshold.. . ... Jfe Steel Corporation

06/02/16 / #20160151837

Mixed powder for powder metallurgy, method of manufacturing same, and method of manufacturing iron-based powder sintered body

A mixed powder for powder metallurgy includes a machinability improvement powder that is crystalline layered alkaline silicate heat-treated at 400° c. To 1100° c. ... Jfe Steel Corporation

06/02/16 / #20160151822

Method of manufacturing hot-pressed member

A method of manufacturing a hot-pressed member including heating a coated steel sheet to 850° c. To 950° c., the coated steel sheet including a substrate steel sheet and a coating layer formed on the substrate steel sheet and containing 10% to 25% by mass of ni and the balance being zn and incidental impurities, in which the coating weight of the coating layer is 10 to 90 g/m2 per a side; and starting hot press forming when the temperature of the coated steel sheet which has been heated is 650° c. ... Jfe Steel Corporation

05/26/16 / #20160148365

Abnormality detection method and blast furnace operation method

. . An abnormality detection method of detecting abnormality of a blast furnace from tuyere images shot by cameras installed in vicinities of a plurality of tuyeres of the blast furnace includes: collecting, in a time-series manner, representative brightness vectors defined by representative brightnesses determined based on brightness values of respective pixels for each of the tuyeres image previously shot by the cameras at a same time; extracting a principal component vector by performing principal component analysis on the representative brightness vectors collected in the time-series manner; calculating, as an evaluation value, a length of a normal line drawn in a direction of the principal component vector from the representative brightness vector collected from the tuyere images shot by the cameras at the same time during an operation; and detecting the abnormality of the blast furnace by comparing the evaluation value with a predetermined threshold.. . ... Jfe Steel Corporation

05/26/16 / #20160145710

High-carbon hot-rolled steel sheet and method for manufacturing the same

There is provided a high-carbon hot-rolled steel sheet and method for producing the same. The steel sheet has excellent hardenability consistently, even when annealed in a nitrogen atmosphere, and excellent workability. ... Jfe Steel Corporation

05/26/16 / #20160145709

High-carbon hot-rolled steel sheet and method for producing the same

There is provided is a high-carbon hot-rolled steel sheet and method for producing the same. The steel sheet has excellent hardenability consistently, even when annealed in a nitrogen atmosphere, and excellent formability. ... Jfe Steel Corporation

05/26/16 / #20160144600

Steel sheet for hot press-forming (as amended)

A steel sheet for hot press-forming having a first coating layer on a surface of the steel sheet, containing 60% or more by mass ni and a remainder composed of zn and incidental impurities, a coating mass thereof being more than 5 g/m2 and 50 g/m2 or less per side, and a second coating layer on the first coating layer, containing 10% to 25% by mass ni and a remainder composed of zn and incidental impurities, a coating mass thereof being 10 to 90 g/m2 per side.. . ... Jfe Steel Corporation

05/26/16 / #20160144449

Indirect spot welding method

This indirect spot welding is for welding members including at least two overlapping steel sheets that have a ferrite phase as a main phase by holding a welding electrode (23) against a steel sheet (21) from one side while applying pressure with the electrode (23), attaching a feeding point (24) to a steel sheet (22) at the other side at a location remote from the electrode (23), and allowing current to flow between the electrode (23) and the feeding point (24). This welding includes contacting magnetic rigid bodies (26-1, 26-2) to a peripheral area of the electrode (23) from the one side against which the electrode (23) is held and securing an overlapping region in the peripheral area of the electrode (23) by a magnetic force produced by the rigid bodies (26-1, 26-2), thereby obtaining a weld having fully satisfactory strength, regardless of the rigidity of the members.. ... Jfe Steel Corporation

05/19/16 / #20160138141

High strength hot rolled steel sheet having tensile strength of 780 mpa or more

A high strength hot rolled steel sheet with good formability, which has good magnetic properties, excellent punchability, and a tensile strength of 780 mpa or more. The high strength hot rolled steel sheet having a chemical composition containing c: 0.070% to 0.140%, si: 0.10% to 1.00%, mn: 1.00% to 1.80%, p: 0.050% or less, s: 0.0050% or less, n: 0.0080% or less, al: 0.010% to 0.100%, ti: 0.050% to 0.150%, and the remainder composed of fe and incidental impurities, on a percent by mass basis, and 95% or more of bainite microstructure on a volume fraction basis, wherein carbides constituting 80% or more of total precipitation carbides are dispersed at grain boundaries of bainitic ferrite constituting the bainite microstructure and 80% or more of total precipitation carbides have particle grain sizes of 20 to 300 nm.. ... Jfe Steel Corporation

05/19/16 / #20160138126

High strength hot rolled steel sheet and method for manufacturing the same

There is provided a high strength hot rolled steel sheet having a composition comprising c: 0.040% to 0.100%, by mass %, si: 0.50% or less, by mass %, mn: 1.00% to 2.00%, by mass %, p: 0.03% or less, by mass %, s: 0.006% or less, by mass %, al: 0.08% or less, by mass %, n: 0.0080% or less, by mass %, ti: 0.14% to 0.22%, by mass %, and fe and incidental impurities, and a method for making the same. The high strength hot rolled steel sheet includes a microstructure in which a primary phase is a ferrite phase and fine carbides containing ti are dispersion-precipitated.. ... Jfe Steel Corporation

05/19/16 / #20160138120

Blast furnace operation method

A method of operating a blast furnace by blowing a pulverized coal at an amount of not less than 150 kg/t−p from tuyeres through a lance into a blast furnace, wherein when the operation is performed under a condition that lump coke charged from a furnace top has a strength defined in jis k2151 (di15015) of not more than 87%, the pulverized coal blown through the tuyere contains not more than 60 mass % as a weight ratio of coal having a particle size of not more than 74 μm and has an average volatile matter of not more than 25 mass %, and a blast temperature blown through the tuyere is not higher than 1100° c., oxygen is simultaneously blown into the furnace with the blowing of the pulverized coals through the lance and a gas having an oxygen concentration of 60 vol %-97 vol % is used as a carrier gas for the blowing of the pulverized coal.. . ... Jfe Steel Corporation

05/19/16 / #20160136727

Alloy steel powder for powder metallurgy and method of producing iron-based sintered body

Provided is an alloy steel powder for powder metallurgy containing an iron-based powder as a main component that is capable of achieving both high strength and high toughness in a sintered body using the same. In the alloy steel powder, the iron-based powder contains a reduced powder, and mo content with respect to a total amount of the alloy steel powder is 0.2 mass % to 1.5 mass %, cu powder content with respect to a total amount of the alloy steel powder is 0.5 mass % to 4.0 mass % and graphite powder content with respect to a total amount of the alloy steel powder is 0.1 mass % to 1.0 mass %.. ... Jfe Steel Corporation

05/12/16 / #20160133368

Grain-oriented electrical steel sheet and transformer iron core using same

A grain-oriented electrical steel sheet subjected to magnetic domain refining by linearly introducing strains in a direction intersecting a rolling direction of the steel sheet repeatedly with intervals in the rolling direction, wherein if a repeating interval of the strains in the rolling direction is d (mm) and, when the steel sheet is placed on a flat surface, a mean value of difference between a height from the flat surface in linear strain-introduced areas of a steel sheet surface and a height from the flat surface in intermediate points between adjacent linear strain-introduced areas is h (mm), then the ratio h/d of the h to the d is 0.0025 or more and 0.015 or less.. . ... Jfe Steel Corporation

05/12/16 / #20160130884

Threaded joint for oil country tubular goods (as amended)

In a joint for oil country tubular goods, a pitch change is made such that an internally-thread pitch has the same value as an externally-thread pitch from a thread end portion on a box end side to a pitch change position taken on a box center side with respect to a position away from the thread end portion by ½ of an entire length of the threaded portion, and the internally-thread pitch is changed to a value less than the externally-thread pitch at the pitch change position so that a thread gap is gradually decreased from the pitch change position to a position of the thread end portion on the box center side, and the thread gap is eventually set to a value which is 0.2 to 0.8 times as large as the thread gap before the pitch change is made.. . ... Jfe Steel Corporation

05/05/16 / #20160123091

Threaded joint for oil country tubular goods

A threaded joint for an oil country tubular goods includes pins each of which occupies a pipe end portion of a steel pipe for an oil country tubular goods, and includes an externally-threaded portion, a nose extending toward a pipe end side from the externally-threaded portion, and a shoulder forming a distal end of the nose; and a box including internally-threaded portions each forming a threaded portion by being threadedly joined with the externally-threaded portion, and shoulders brought into contact with the shoulders of the pins, wherein the pins and the box being joined to each other by the threaded joining so that portions between the threaded portions and the shoulders are brought into metal-to-metal contact with each other to thereby form seal portions at the contact portions, and the shoulders of the pins and the shoulders of the box forming shoulder faces are brought into contact with each other at the time of make-up of the threaded joint, and a ratio of a chamfer length of pin thread to a thread pitch is 1.0 or more to 3.0 or less.. . ... Jfe Steel Corporation

05/05/16 / #20160121384

Method of press forming and press forming apparatus

A method of press forming includes: forming a trench-shaped portion into a product shape with a die and a punch until reaching a first bottom dead center, and forms at least one of: a flange portion subject to shrink flange deformation such that a linear length of the flange portion subject to the shrink flange deformation in a longitudinal direction is shorter than a linear length of a flange portion in the product shape; and a flange portion subject to stretch flange deformation such that a linear length of the flange portion subject to the stretch flange deformation in the longitudinal direction is longer than the linear length of the flange portion in the product shape; and forming the formed flange portion into the product shape with the die and a flange forming die until reaching a second bottom dead center.. . ... Jfe Steel Corporation

04/28/16 / #20160114391

Finish heat treatment method and finish heat treatment apparatus for iron powder

In a finish heat treatment method and finish heat treatment apparatus for an iron powder, a raw iron powder is placed on a continuous moving hearth and continuously charged into the apparatus. In the pretreatment zone, the raw iron powder is subjected to a pretreatment of heating the raw iron powder in an atmosphere of hydrogen gas and/or inert gas at 450 to 1100° c. ... Jfe Steel Corporation

03/24/16 / #20160084816

Method for evaluating weathering degree of coal, method for evaluating coking property of weathered coal, method for controlling weathering degree of coal, and method for producing coke (as amended)

Provided are, by using an index with which the influence on the strength of coke can be evaluated, a method for evaluating a weathering degree of coal and a coking property of weathered coal within the ranges in which the weathering degree and coking property cannot be determined by using conventional methods, and a method for controlling the weathering degree of coal with which it is possible to add weathered coal to a coal blend to be used for producing coke without decreasing the strength of coke by using the index. The weathering degree of coal is evaluated by using the surface tension of semicoke which is prepared by performing a heat treatment on weathered coal as an index. ... Jfe Steel Corporation

03/24/16 / #20160083820

Pearlitic rail and method for manufacturing pearlitic rail

A pearlitic rail includes a composition including in % by mass: 0.70% to 0.90% of c; 0.1% to 1.5% of si; 0.01% to 1.5% of mn; 0.001% to 0.035% of p; 0.0005% to 0.030% of s; 0.1% to 2.0% of cr, remainder of the composition consisting of fe and inevitable impurities. Surface hardness of a rail top is not less than hb 430, and hardness at a depth of 25 mm from a surface of the rail top is not less than hb 410.. ... Jfe Steel Corporation

03/24/16 / #20160083819

High-strength steel sheet and method for producing the same

There is provided a high-strength steel sheet having a tensile strength (ts) of 900 mpa or more and excellent elongation, stretch flangeability, and bendability in a component system in which an expensive alloy element is not intentionally added. A high-strength steel sheet includes a composition including, on a mass % basis, c: 0.15 to 0.40%, si: 1.0 to 2.0%, mn: 1.5 to 2.5%, p: 0.020% or less, s: 0.0040% or less, al: 0.01 to 0.1%, n: 0.01% or less, and ca: 0.0020% or less, with the balance including fe and incidental impurities. ... Jfe Steel Corporation

03/17/16 / #20160076125

Non-oriented electrical steel sheet having an excellent high-frequency iron loss property

A non-oriented electrical steel sheet has a chemical composition that includes c: not more than 0.005%, si: 1.5-4%, mn: 1.0-5%, p: not more than 0.1%, s: not more than 0.005%, al: not more than 3 mass %, n: not more than 0.005 mass %, bi: not more than 0.0030% as mass % and the remainder being fe and inevitable impurities or a chemical composition containing c: not more than 0.005%, si: 1.5-4%, mn: 1.0-5%, p: not more than 0.1%, s: not more than 0.005%, al: not more than 3 mass %, n: not more than 0.005 mass %, bi: not more than 0.0030% and further one or two of ca: 0.0005-0.005% and mg: 0.0002-0.005%, and is stably excellent in the high-frequency iron loss property even if a great amount of mn is included.. . ... Jfe Steel Corporation

03/17/16 / #20160076124

High strength hot rolled steel sheet and method for manufacturing the same (as amended)

A high strength hot rolled steel sheet having a tensile strength ts of 980 mpa or more, has a composition containing, on a percent by mass basis, c: 0.05% or more and 0.18% or less, si: 1.0% or less, mn: 1.0% or more and 3.5% or less, p: 0.04% or less, s: 0.006% or less, al: 0.10% or less, n: 0.008% or less, ti: 0.05% or more and 0.20% or less, v: more than 0.1% and 0.3% or less, and the balance being fe and incidental impurities, and has a microstructure including a primary phase and a secondary phase, the primary phase being a bainite phase having an area fraction of more than 85%, the secondary phase being at least one of ferrite phase, martensite phase, and retained austenite phase, the secondary phase having an area fraction of 0% or more and less than 15% in total, the bainite phase having an average lath interval of laths of 400 nm or less, and the laths having an average long axis length of 5.0 μm or less.. . ... Jfe Steel Corporation

03/10/16 / #20160068937

High-strength hot-rolled steel sheet and method for producing the same (as amended)

A steel slab having a composition containing c: more than 0.07% and 0.2% or less, si: 2.0% or less, mn: 1.0% to 3.0%, al: 0.1% or less, ti: 0.05% to 0.3%, and v: 0.05% to 0.3% on a mass percent basis is heated to 1100° c. Or more and is subjected to rough rolling and finish rolling. ... Jfe Steel Corporation

03/03/16 / #20160064574

Ferritic stainless steel foil for solar cell

. . A ferritic stainless steel foil for a solar cell substrate excellent in terms of threading performance. The ferritic stainless steel foil for a solar cell substrate may have a chemical composition containing, by mass %, cr: 14% or more and 24% or less and nb: 0.1% or more and 0.6% or less, and optionally further containing mo: 2.0% or less, a vickers hardness of hv250 or more and hv450 or less, and a vickers hardness of hv250 or more and hv450 or less after the substrate has undergone an optical absorber layer growth process in which the substrate is held in a temperature range of 450° c. ... Jfe Steel Corporation

03/03/16 / #20160060738

Steel structure for hydrogen gas, mehtod for producing hydrogen storage tank, and method for producing hydrogen line pipe (as amended)

Provided is a steel structure for hydrogen gas such as a hydrogen storage tank or a hydrogen line pipe which achieves a lower fatigue crack propagation rate in a high-pressure hydrogen atmosphere than steels used in the related art and has high hydrogen embrittlement resistance. The steel structure for hydrogen gas, which has high hydrogen embrittlement resistance in high-pressure hydrogen gas, has a steel microstructure including any one of 10% to 95% of bainite on an area-ratio basis, 10% to 95% of martensite on an area-ratio basis, and 10% to 95% of pearlite on an area-ratio basis, with the balance being substantially ferrite.. ... Jfe Steel Corporation

03/03/16 / #20160060723

High strength hot-rolled steel sheet and method of producing the same

A high-strength hot-rolled steel sheet has a tensile strength ts of 980 mpa or more and is manufactured by controlling the steel sheet to have a chemical composition containing c: more than 0.1% and 0.2% or less, si: 0.5% or more and 3.0% or less, mn: 1.0% or more and 3.5% or less, p: 0.05% or less, s: 0.004% or less, al: 0.10% or less, n: 0.008% or less, ti: 0.05% or more and 0.15% or less, v: more than 0.10% and 0.30% or less, and the balance being fe and inevitable impurities. Surface regions have a microstructure including mainly a ferrite phase, and an inner region has a microstructure including mainly a bainite phase. ... Jfe Steel Corporation

02/25/16 / #20160054266

Ultrasonic flaw detection method and ultrasonic flaw detection apparatus

An ultrasonic flaw detection method includes a condition setting step of setting a boundary echo detection threshold and a gate end point relative position, according to a type of a test object, a flaw detection signal obtaining step of obtaining a flaw detection signal by converting ultrasonic waves received from the test object to an electric signal, a boundary echo detection step of detecting a boundary echo detection time of the flaw detection signal by using the boundary echo detection threshold, a flaw echo detection gate setting step of setting an end point of a flaw echo detection gate by subtracting the gate end point relative position from the boundary echo detection time, and a flaw echo detection step of detecting a flaw echo by using the flaw detection signal within the flaw echo detection gate.. . ... Jfe Steel Corporation

02/25/16 / #20160053355

Steel material, hydrogen container, method for producing the steel material, and method for producing the hydrogen container (as amended)

A steel material includes: a composition containing, by mass, c: 0.05% to 0.60%, si: 0.01% to 2.0%, mn: 0.3% to 3.0%, p: 0.001% to 0.040%, s: 0.0001% to 0.010%, n: 0.0001% to 0.0060%, al: 0.01% to 1.5%, one or more elements selected from ti: 0.01% to 0.20%, nb: 0.01% to 0.20%, and v: 0.01% or more and less than 0.05%, and one or more elements selected from b: 0.0001% to 0.01%, mo: 0.005% to 2.0%, and cr: 0.005% to 3.0%, with the balance being fe and inevitable impurities; and a steel microstructure that includes 95% or more of tempered martensite on a volume fraction basis, that includes a precipitate having a diameter of 100 nm or less and including one or more elements selected from ti, nb, and v and one or more elements selected from carbon and nitrogen at a density of 50 particles/μm2 or more, and that includes prior austenite having a grain diameter of 3 μm or more.. . ... Jfe Steel Corporation

02/25/16 / #20160053354

Steel plate for thick-walled steel pipe, method for manufacturing the same, and thick-walled high-strength steel pipe (as amended)

A steel plate has a chemical composition containing, by mass %, c: 0.03% or more and 0.10% or less, si: 0.05% or more and 0.50% or less, mn: 1.00% or more and 2.00% or less, p: 0.015% or less, s: 0.005% or less, mo: 0.20% or less (including 0%), nb: 0.01% or more and 0.05% or less, and the balance being fe and inevitable impurities, and, if desired, containing, by mass %, one or more of al: 0.005% or more and 0.1% or less, cu: 1.00% or less, ni: 1.00% or less, cr: 0.50% or less, and v: 0.05% or less, in which pcm* (%) (=c+si/30+(mn+cu+cr)/20+ni/60+mo/2+v/10) is 0.20 or less. The steel plate has a volume fraction of bainite in a base material of 50% or more, and has a volume fraction of island martensite (ma) in a coarse-grain region reheated in a dual-phase temperature range of 5.0% or less. ... Jfe Steel Corporation

02/25/16 / #20160053338

Blast furnace operation method

A method is provided for operating a blast furnace by blowing at least a solid reducing material and a combustible gas into the furnace through tuyeres with a lance inserted into a blowpipe, wherein a tube-bundle type lance obtained by bundling a plurality of blowing tubes is used and when only a solid reducing material or two kinds of a solid reducing material and a combustible gas or three kinds of a solid reducing material, a combustible gas and a gaseous reducing material is simultaneously blown into an inside of the blast furnace through a tube for blowing the solid reducing material, a tube for blowing the combustible gas and a tube for blowing the gaseous reducing material in the tube-bundle type lance, two or more tube-bundle type lances are inserted into the blowpipe to approximate their front ends to each other and blowing is performed so that the respective blowout streams interfere with each other in the blowpipe.. . ... Jfe Steel Corporation

02/18/16 / #20160049534

Ferritic stainless steel foil for solar cell substrate

Provided is a ferritic stainless steel foil for a solar cell substrate excellent in terms of threading performance with which it is possible to maintain sufficient hardness to suppress, for example, buckling during threading when a solar cell is manufactured using a roll-to-roll method. The ferritic stainless steel foil for a solar cell substrate has a chemical composition containing, by mass %, cr: 14% or more and 18% or less, a vickers hardness of hv250 or more, and a vickers hardness of hv250 or more after the substrate has undergone an optical absorber layer growth process in which the substrate is held in a temperature range of 450° c. ... Jfe Steel Corporation

02/18/16 / #20160047025

High-strength galvannealed steel sheet and method for manufacturing the same (as amended)

A high-strength galvannealed steel sheet has a chemical composition containing, by mass %, c: 0.14% or more and 0.24% or less, si: 0.8% or more and 1.8% or less, mn: 1.0% or more and 3.0% or less, p: 0.020% or less, s: 0.0040% or less, al: 0.01% or more and 0.1% or less, n: 0.01% or less, ca: 0.0001% or more and 0.0020% or less, and the balance including fe and incidental impurities, and a microstructure, in which the total area ratio of a ferrite phase and a bainite phase with respect to the whole microstructure is 30% or more and 70% or less, in which the area ratio of a tempered martensite phase with respect to the whole microstructure is 20% or more and 40% or less, in which the area ratio of a retained austenite phase with respect to the whole microstructure is 1% or more and 5% or less, in which the area ratio of a martensite phase with respect to the whole microstructure is 2% or more and 20% or less, and in which the total area ratio of cementite and a pearlite phase with respect to the whole microstructure is 10% or less.. . ... Jfe Steel Corporation

02/18/16 / #20160047018

Aluminum-zinc-coated steel sheet (as amended)

An al—zn-coated steel sheet that suppresses blistering and offers good corrosion resistance after painting is provided. The al—zn-coated steel sheet includes an al—zn coating layer on a steel sheet surface, the al—zn coating layer including two layers which are an interfacial alloy layer present in an interface with a base steel sheet and an upper layer disposed on the interfacial alloy layer. ... Jfe Steel Corporation

02/18/16 / #20160047011

High-strength galvanized steel sheet and method for manufacturing the same (as amended)

A high-strength galvanized steel sheet has a chemical composition containing, by mass %, c: 0.16% or more and 0.24% or less, si: 0.8% or more and 1.8% or less, mn: 1.0% or more and 3.0% or less, p: 0.020% or less, s: 0.0040% or less, al: 0.01% or more and 0.1% or less, n: 0.01% or less, ca: 0.0001% or more and 0.0020% or less, and the balance including fe and incidental impurities, and a microstructure, in which the total area ratio of a ferrite phase and a bainite phase with respect to the whole microstructure is 30% or more and 70% or less, in which the area ratio of a tempered martensite phase with respect to the whole microstructure is 20% or more and 40% or less, in which the area ratio of a retained austenite phase with respect to the whole microstructure is 10% or more and 20% or less, and in which the area ratio of a martensite phase with respect to the whole microstructure is 2% or more and 20% or less.. . ... Jfe Steel Corporation

02/18/16 / #20160045976

Indirect spot welding method

An oval nugget can reliably be obtained with this indirect spot welding method. In this indirect spot welding method, an electrode end portion of a welding electrode includes a tip of the welding electrode, and as viewed from the tip, the electrode end portion has a two-step dome shape formed by a first curved surface with a curvature radius r1 (mm) located within a range of a circle of radius r (mm) centering on the tip and a second curved surface with a curvature radius r2 (mm). ... Jfe Steel Corporation

02/18/16 / #20160045974

Open-pipe weld shielding system for electric resistance welded steel pipe or tube

An open-pipe weld shielding arrangement for an electric resistance welded steel pipe or tube includes a shielding-gas blowing nozzle and a gas flow rate controller. The shielding-gas blowing nozzle includes a gas outlet disposed at a position 5 to 300 mm above upper ends of portions to be welded, and the gas flow rate controller controls the flow rate of the shielding gas blown from the gas outlet to 0.5 to 50 m/sec.. ... Jfe Steel Corporation

02/11/16 / #20160042850

Non-oriented electrical steel sheet having excellent magnetic properties (as amended)

. . A non-oriented electrical steel sheet having a high magnetic flux density and a low anisotropy contains c: not more than 0.01 mass %, si: 1-4 mass %, mn: 0.05-3 mass %, p: 0.03-0.2 mass %, s: not more than 0.01 mass %, al: not more than 0.004 mass %, n: not more than 0.005 mass %, as: not more than 0.003 mass %, and preferably further contains one or two of sb: 0.001-0.1 mass % and sn: 0.001-0.1 mass % or further contains one or two of ca: 0.001-0.005 mass % and mg: 0.001-0.005 mass %.. . ... Jfe Steel Corporation

02/11/16 / #20160040263

Rail manufacturing method and manufacturing equipment

Rail manufacturing method performs, on at least a head of the rail that is hot after hot-rolled at an austenite region temperature or higher or after heated to the austenite region temperature or higher, forced cooling: for 10 seconds from start of the forced cooling so that a cooling rate at a surface of the head becomes 1° c./s to 20° c./s; during a period after a lapse of 10 seconds from the start until heat generation during transformation begins at the surface so that the cooling rate becomes 1° c./s to 5° c./s; during transformation from beginning to end of the heat generation during transformation so that the cooling rate becomes lower than 1° c./s or a temperature-rising rate becomes 5° c./s or lower; and during a period after the end of the heat generation during transformation until temperature at the surface becomes 450° c. Or lower so that the cooling rate becomes 1° c./s to 20° c./s.. ... Jfe Steel Corporation

02/11/16 / #20160040261

Blast furnace operation method and lance

A method is provided for operating a blast furnace by blowing a solid reducing material, a flammable gaseous reducing material and a combustible gas into a blast furnace from tuyeres through a lance into a blast furnace, wherein a parallel type lance prepared by bundling three independent blowing tubes in parallel and integrally housing them into an outer tube is used, and either one or both of the gaseous reducing material and the combustible gas and the solid reducing material are simultaneously blown through the respective blowing tubes, while the blowing tube for the solid reducing material and the blowing tube for the gaseous reducing material are positioned above the blowing tube for the combustible gas in the blowing through the parallel type lance as well as a lance structure thereof.. . ... Jfe Steel Corporation

02/04/16 / #20160032431

Steel sheet for nitriding and production method therefor

A steel sheet for nitriding has excellent formability and punchability. The steel sheet has a composition including, in percent by mass, 0.02% to 0.08% of c, 0.1% or less of si, 0.2% to 1.8% of mn, 0.05% or less of p, 0.02% or less of s, 0.01% to 0.06% of al, 0.5% to 1.5% of cr, 0.01% or less of n, and the balance being fe and incidental impurities; and has a microstructure including ferrite as a main phase and pearlite and/or bainite as a secondary phase. ... Jfe Steel Corporation

02/04/16 / #20160030968

Coating device and coating method

A coating device includes: a first roll including a roll surface on which an application liquid is deposited; a first scratch off member configured to scratch off the application liquid from the roll surface of the first roll; a second roll including a roll surface configured to contact with the roll surface of the first roll, wherein the second roll is configured to rotate in a rotation direction opposite to a rotation direction of the first roll, the application liquid is transferred from the roll surface of the first roll to the roll surface of the second roll, and the second roll is configured to transfer the transferred application liquid to a steel strip; and a second scratch off member configured to scratch off the application liquid from the roll surface of the second roll.. . ... Jfe Steel Corporation

01/28/16 / #20160024660

Method for manufacturing galvanized steel sheet (as amended)

There is provided a method for manufacturing a galvanized steel sheet that has low sliding resistance in press forming and good degreasing property even under severe alkaline degreasing treatment conditions due to low temperature and short process line length. An oxide layer formed on the surface of a galvanized steel sheet is subjected to neutralization treatment using an alkaline aqueous solution containing 0.01 g/l or more of p ions and 0.01 g/l or more of colloid dispersed particles, wherein the alkaline aqueous solution preferably contains at least one phosphorus compound selected from phosphates, pyrophosphates, and triphosphates and at least one type of colloid dispersed particles selected from ti, silica, pt, pd, zr, ag, cu, au, and mg.. ... Jfe Steel Corporation

01/21/16 / #20160020007

Non-oriented electrical steel sheet having excellent high-frequency iron loss property

. . A non-oriented electrical steel sheet has a chemical composition including c: not more than 0.005 mass %, si: 1.5-4 mass %, mn: 1-5 mass %, p: not more than 0.1 mass %, s: not more than 0.005 mass %, al: not more than 3 mass %, n: not more than 0.005 mass %, pb: not more than 0.001 mass % and the remainder being fe and inevitable impurities or a chemical composition including c: not more than 0.005 mass %, si: 1.5-4 mass %, mn: 1-5 mass %, p: not more than 0.1 mass %, s: not more than 0.005 mass %, al: not more than 3 mass %, n: not more than 0.005 mass %, pb: not more than 0.0020 mass % and further one or two of ca: 0.0005-0.007 mass % and mg: 0.0002-0.005 mass %, and has a stable and excellent high-frequency iron loss property even when mn content is high.. . ... Jfe Steel Corporation

01/21/16 / #20160020006

Method for producing grain-oriented electrical steel sheet

In a method for producing a grain-oriented electrical steel sheet by comprising a series of steps of hot rolling a raw steel material comprising c: 0.002-0.10 mass %, si: 2.0-8.0 mass %, and mn: 0.005-1.0 mass %, subjecting the steel sheet to a hot band annealing as required, cold rolling to obtain a cold rolled sheet having a final sheet thickness, subjecting the steel sheet to primary recrystallization annealing combined with decarburization annealing, applying an annealing separator to the steel sheet surface and then subjecting to final annealing, rapid heating is performed at a rate of not less than 50° c./s in a region of 200-700° c. In the heating process of the primary recrystallization annealing, and the steel sheet is held at any temperature of 250-600° c. ... Jfe Steel Corporation

01/21/16 / #20160017473

High strength galvanized steel sheet having excellent bendability and weldability, and method of manufacturing the same

A method of manufacturing a galvanized steel sheet includes a two-stage temperature raising process which includes: primary heating the sheet from 200° c. To an intermediate temperature of 500 to 800° c. ... Jfe Steel Corporation

01/21/16 / #20160017466

Hot-rolled steel sheet and method for producing the same (as amended)

A hot-rolled steel sheet is provided having high strength and excellent toughness and ductility includes a composition that contains, on a mass percent basis, 0.04% or more and 0.15% or less of c, 0.01% or more and 0.55% or less of si, 1.0% or more and 3.0% or less of mn, 0.03% or less p, 0.01% or less s, 0.003% or more and 0.1% or less of al, 0.006% or less n, 0.035% or more and 0.1% or less nb, 0.001% or more and 0.1% or less of v, 0.001% or more and 0.1% or less ti, and the balance being fe and incidental impurities, in which the hot-rolled steel sheet includes a microstructure in which the proportion of precipitated nb to the total amount of nb is 35% or more and 80% or less, the volume fraction of tempered martensite and/or tempered bainite having a lath interval of 0.2 μm or more and 1.6 μm or less is 95% or more at a position 1.0 mm from a surface of the sheet in the thickness direction, and the volume fraction of ferrite having a lath interval of 0.2 μm or more and 1.6 μm or less at the center position of the sheet in the thickness direction is 95% or more.. . ... Jfe Steel Corporation

01/21/16 / #20160017456

Thick steel sheet having excellent ctod properties in multilayer welded joints, and manufacturing method for thick steel sheet

There is provided a thick steel plate having good multipass weld joint ctod characteristics for low to medium heat input and a method for manufacturing the thick steel plate. A steel plate containing, on a mass percent basis, c: 0.03% to 0.12%, si: 0.5% or less, mn: 1.0% to 2.0%, p: 0.015% or less, s: 0.0005% to 0.0050%, al: 0.005% to 0.060%, ni: 0.5% to 2.0%, ti: 0.005% to 0.030%, n: 0.0015% to 0.0065%, o: 0.0010% to 0.0050%, ca: 0.0005% to 0.0060%, and optionally one or two or more of cu and the like, wherein ti/n, ceq, pcm, and acr are in particular ranges, a base material of the plate has an effective grain size of 20 μm or less at half the thickness of the plate, and the plate contains a particular number of complex inclusions at ¼ and ½ of the thickness of the plate, the complex inclusions being composed of a sulfide containing ca and mn and an oxide containing al and having an equivalent circular diameter of 0.1 μm or more. ... Jfe Steel Corporation

01/14/16 / #20160012949

Method for producing grain-oriented electrical steel sheet (as amended)

. . In a method for producing a grain-oriented electrical steel sheet by hot rolling a raw steel material containing c: 0.002˜0.10 mass %, si: 2.0˜8.0 mass % and mn: 0.005˜1.0 mass % to obtain a hot rolled sheet, subjecting the hot rolled sheet to a hot band annealing as required and further to one cold rolling or two or more cold rollings including an intermediate annealing therebetween to obtain a cold rolled sheet having a final sheet thickness, subjecting the cold rolled sheet to a primary recrystallization annealing combined with decarburization annealing, applying an annealing separator to the steel sheet surface and then subjecting to a final annealing, when rapid heating is performed at a rate of not less than 50° c./s in a range of 100˜700° c. In the heating process of the primary recrystallization annealing, the steel sheet is subjected to a holding treatment at any temperature of 250˜600° c. ... Jfe Steel Corporation

01/14/16 / #20160012948

Method for producing grain-oriented electrical steel sheet (as amended)

In a method for producing a grain-oriented electrical steel sheet by hot rolling a steel slab comprising c: 0.04-0.12 mass %, si: 1.5-5.0 mass %, mn: 0.01-1.0 mass %, sol. Al: 0.010-0.040 mass %, n: 0.004-0.02 mass %, one or two of s and se: 0.005-0.05 mass % in total of s and se, cold rolling, and subjecting to primary recrystallization annealing and further to final annealing, a content ratio of sol. ... Jfe Steel Corporation

01/14/16 / #20160010192

Thick, tough, high tensile strength steel plate and production method therefor

A thick, high-toughness high-strength steel plate has excellent strength and toughness in the central area through the plate thickness. The thick steel plate has a specific chemical composition and includes a microstructure having, throughout an entire region in the plate thickness direction, an average prior austenite grain size of not more than 50 μm and a martensite and/or bainite phase area fraction of not less than 80%. ... Jfe Steel Corporation

01/14/16 / #20160009444

Laminated metal sheet for two-piece can and two-piece laminated can body (as amended)

A laminated metal sheet for a two-piece can includes: a metal sheet; and first and second polyester resin layers formed on outer and inner face sides of the container, respectively. The first polyester resin layer contains polyethylene terephthalate or a copolymerized polyethylene terephthalate with a content of a copolymerized component of less than 6 mol % in a ratio of 30% to 60% by mass, polybutylene terephthalate or a copolymerized polybutylene terephthalate with a content of a copolymerized component of less than 5 mol % in a ratio of 40% to 70% by mass, and a polyolefinic wax in an amount of 0.01% to 3.0% in outer percentage, the second polyester resin layer is a copolymerized polyethylene terephthalate with a content of a copolymerized component of less than 22 mol %, and residual degrees of orientation of the first and the second polyester resin layers are less than 30%.. ... Jfe Steel Corporation

01/14/16 / #20160008914

Resistance spot welding system

A resistance spot welding system includes a calculation unit that calculate and store a time variation of an instantaneous amount of heat generated, a division unit that divides a current pattern into a plurality of steps and stores a time variation of the instantaneous amount of heat generated and a cumulative amount of heat generated for each step as a target value, and an adaptive control unit that starts welding upon subsequent actual welding using, as a standard, a time variation curve of the instantaneous amount of heat generated that is stored as the target value, and adjusts welding current and voltage during welding, when a time variation amount of an instantaneous amount of heat generated deviates during any step from the time variation curve by a difference, so as to compensate for the difference during a remaining welding time in the step.. . ... Jfe Steel Corporation

01/14/16 / #20160008913

Resistance spot welding method

Proposed is a method of resistance spot welding to join a plurality of overlapping metal sheets, including: dividing a current pattern into two or more steps for welding; before actual welding, performing test welding to store, for each step as a target value, a time variation of an instantaneous amount of heat generated per unit volume and a cumulative amount of heat generated per unit volume; and subsequently, as actual welding, starting welding using, as a standard, a time variation curve of the instantaneous amount of heat generated per unit volume obtained by the test welding, and when a time variation amount of an instantaneous amount of heat generated deviates during any step from the time variation curve by a difference, performing adaptive control welding to control a current passage amount in order to compensate for the difference during a remaining welding time in the step.. . ... Jfe Steel Corporation

01/07/16 / #20160004793

Method and device for analysis of shape optimization

A method for analysis of shape optimization includes: setting, as a design space, a portion to be optimized in a movable portion; generating, in the set design space, an optimization block model formed of three-dimensional elements and is to be subjected to analysis processing of optimization; connecting the generated optimization block model with a structural body model; setting a material property for the optimization block model; setting an optimization analysis condition for finding an optimum shape of the optimization block model; setting a multi-body dynamics analysis condition for performing multi-body dynamics analysis on the structural body model with which the optimization block model has been connected; and executing, based on the set optimization analysis condition and multi-body dynamics analysis condition, the multi-body dynamics analysis on the optimization block model and finding the optimum shape of the optimization block model.. . ... Jfe Steel Corporation

01/07/16 / #20160002807

Process of manufacturing high-strength cold rolled steel sheets

A process of manufacturing high-strength cold rolled steel sheets containing 0.5 to 2.0 mass % silicon includes a pickling step of thermally annealing a steel sheet in a non-oxidizing atmosphere and thereafter pickling the steel sheet to dissolve away 0.5 g/m2 to less than 2.0 g/m2 of the steel sheet, and an electroplating step of electroplating the surface of the pickled steel sheet with zinc under such conditions that a coating mass of 100 to 5000 mg/m2 is obtained.. . ... Jfe Steel Corporation

01/07/16 / #20160002762

High-strength steel sheet and production method therefor and high-strength galvanized steel sheet and production method therefor (as amended)

Provided is a high-strength steel sheet that has good chemical convertibility and good corrosion resistance after electro deposition painting despite high si and mn contents. Also provided are a method for producing the high-strength steel sheet, a high-strength galvanized steel sheet formed by using the high-strength steel sheet, and a method for producing the high-strength galvanized steel sheet. ... Jfe Steel Corporation








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