Abstract: To provide a roller scraper capable of having a long service life. A roller scraper that removes attached substances on a surface of a roller, the roller scraper including a scraper main body that is supported on a floor portion and a scraping claw that is disposed in such a manner as to project in a width direction of the scraper main body. The scraping claw is placed against the roller in such a manner as to be in contact with the surface of the roller, and an opening is formed in the scraper main body.
Abstract: Provided is a method for manufacturing a grain-oriented electrical steel sheet. The method comprises: hot rolling a slab to obtain a hot rolled sheet; subjecting the hot rolled sheet to hot band annealing as necessary; subjecting the hot rolled sheet to cold rolling; subjecting the cold rolled sheet to decarburization annealing; applying an annealing separator having MgO as a main component onto a surface of the decarburization annealed sheet and subjecting the decarburization annealed sheet to final annealing to form the forsterite film; and applying an insulating coating treatment liquid onto the final annealed sheet and subjecting the final annealed sheet to flattening annealing to form a tension-applying insulating coating. A difference in total tensions between one and opposite surfaces of the sheet is less than 0.5 MPa. A difference in tensions between the forsterite films in one and opposite surfaces of the sheet is 0.5 MPa or more.
Abstract: Provided is a resin-coated metal sheet that, even when used in a DI can, ensures excellent removability for various contents and stably satisfies various properties required of container material. A resin-coated metal sheet comprises: a metal sheet; and a coating layer of a resin containing a polyester resin as a main component, on at least one surface of both surfaces of the metal sheet, wherein the coating layer has a thickness of 21 ?m or more and 38 ?m or less, contains 0.01 mass % or more and 2.00 mass % or less of a wax compound, and has a surface indentation modulus of 2000 MPa or more and 3400 MPa or less.
December 10, 2020
February 2, 2023
JFE STEEL CORPORATION
Yasuhide OSHIMA, Soichi FUJIMOTO, Mitsunori OTA
Abstract: To provide a high-strength seamless stainless steel pipe for oil well that has high strength, is excellent in hot workability, has excellent carbon dioxide gas corrosion resistance, and is excellent in SSC resistance under a low temperature environment. A high-strength seamless stainless steel pipe for oil well having a composition containing the particular components, the balance being Fe and unavoidable impurities, and satisfying certain expressions, having a number density of an inclusion having a major axis of 5 ?m or more and 0.5<Ti/(Ti+Al+Mg+Ca)<1.0 of 0.5 per mm2 or more and 3 per mm2 or less, and having a yield strength of 655 MPa or more, wherein in 0.5<Ti/(Ti+Al+Mg+Ca)<1.0, Ti, Al, Mg, and Ca represent the contents (% by mass) of the elements in the inclusion, and an element that is not contained is designated as 0.
Abstract: Provided is a method of operating a blast furnace, including generating a regenerative methane gas using a blast furnace by-product gas, and blowing a blast gas and a reducing agent into the blast furnace from a tuyere, in which the blast gas is oxygen gas, the regenerative methane gas is used as at least part of the reducing agent, and the oxygen gas and/or the regenerative methane gas is preheated before being blown into the blast furnace from the tuyere.
Abstract: Provided herein is a dual-phase stainless steel having excellent carbon dioxide corrosion resistance, excellent sulfide stress corrosion cracking resistance, and excellent sulfide stress cracking resistance. The dual-phase stainless steel contains, in mass %, C: 0.03% or less, Si: 1.0% or less, Mn: 0.10 to 1.5%, P: 0.030% or less, S: 0.005% or less, Cr: 20.0 to 30.0%, Ni: 5.0 to 10.0%, Mo: 2.0 to 5.0%, Cu: 2.0 to 6.0%, N: less than 0.07%, and the balance Fe and unavoidable impurities, and has a structure that is 20 to 70% austenite phase, and 30 to 80% ferrite phase in terms of a volume fraction.
Abstract: Provided is a grain-oriented electrical steel sheet having better transformer iron loss property than conventional grain-oriented electrical steel sheets. A grain-oriented electrical steel sheet comprises: a steel substrate; a forsterite film on a surface of the steel substrate; and a Cr-depleted layer at a boundary between the steel substrate and the forsterite film, the Cr-depleted layer having a Cr concentration that is 0.70 times to 0.90 times a Cr concentration of the steel substrate.
Abstract: Provided is a rail that is effective in improving wear resistance and rolling contact fatigue (RCF) resistance. The rail has a metallic structure including a pearlitic structure and a structure other than the pearlitic structure in a surface layer from a surface of a rail head to a depth of at least 0.5 mm, where the pearlitic structure has Vickers hardness of 420 HV or more and 520 HV or less, and the structure other than the pearlitic structure has Vickers hardness of 350 HV or more and 420 HV or less.
Abstract: Provided herein is a high-strength seamless steel pipe, and a method for manufacturing same. A high-strength seamless steel pipe of the present invention has a steel microstructure with a prior austenite grain size of 11.0 or more in terms of a grain size number in compliance with ASTM E112, and has a yield strength of 862 MPa or more and 965 MPa or less.
Abstract: Free-cutting steel includes a specific composition, with an A value defined by a following formula (1) satisfying 4.0 or more and 20.0 or less, and remainder having Fe and an unavoidable impurity; and texture with 1000 or more sulfide particles with an equivalent circle diameter of less than 1 ?m per mm2, 500 or more sulfide particles with an equivalent circle diameter of 1 ?m or more and 5 ?m or less per mm2, and 1000 or more Pb particles with an equivalent circle diameter of 1 ?m or less per mm2, wherein A value=(Mn+5Cr)/S ??(1) here, symbols of elements in the formula indicate contents (% by mass) of the elements.
Abstract: Provided are an abnormality diagnosis system and an abnormality diagnosis method that can prevent wrongly diagnosing equipment as having an abnormality when the equipment actually does not have an abnormality. An abnormality diagnosis system 20 comprises a sampler 21 and a calculator 24. The calculator 24 is configured to: perform first abnormality determination of whether there is an abnormality based on a result of first principal component analysis; in the case where a result of the first abnormality determination is that there is an abnormality, and perform second abnormality determination of whether there is an abnormality based on a result of second principal component analysis; and in the case where a result of the second abnormality determination is that there is an abnormality, diagnose the equipment as having an abnormality.
Abstract: Provided is a grain-oriented electrical steel sheet that has excellent magnetic properties and can be manufactured by secondary recrystallization orientation control using coil annealing with high productivity. A grain-oriented electrical steel sheet comprises a specific chemical composition, wherein an average value of a deviation angle (?2+?2)1/2 calculated from a deviation angle ? from ideal Goss orientation around an ND rotation axis and a deviation angle ? from ideal Goss orientation around a TD rotation axis is 5.0° or less, and an area ratio R? of crystal grains with ??0.50° is 20% or less.
Abstract: A high-strength galvanized steel sheet includes a steel sheet having a chemical composition containing a predetermined component element, a mass ratio of a content of Si to a content of Mn in the steel (Si/Mn) being 0.1 or more and less than 0.2, and the balance: Fe and incidental impurities, and a steel structure in which an average grain size of inclusions containing at least one of Al, Si, Mg, and Ca and existing in an area extending from a surface to a position of ? of a sheet thickness is 50 ?m or less, and an average nearest distance between ones of the inclusions is 20 ?m or more; and a galvanized layer provided on a surface of the steel sheet, in which an amount of diffusible hydrogen contained in the steel is less than 0.25 mass ppm, and a tensile strength is 1100 MPa or more.
Abstract: Provided is a ferritic stainless steel in which cracking is unlikely to be caused in the vicinity of a weld zone by the stress due to expansion, contraction, and deformation due to the thermal effect of welding in the case of performing welding after deep drawing and which is excellent in corrosion resistance in the vicinity of the weld zone. The ferritic stainless steel has a composition containing C: 0.001% to 0.020%, Si: 0.01% to 0.30%, Mn: 0.01% to 0.50%, P: 0.04% or less, S: 0.01% or less, Cr: 18.0% to 24.0%, Ni: 0.01% to 0.40%, Mo: 0.30% to 3.0%, Al: 0.01% to 0.15%, Ti: 0.01% to 0.50%, Nb: 0.01% to 0.50%, V: 0.01% to 0.50%, Co: 0.01% to 6.00%, B: 0.0002% to 0.0050%, and N: 0.001% to 0.020% on a mass basis, the remainder being Fe and inevitable impurities. The composition satisfies 0.30%?Ti+Nb+V?0.60%.
Abstract: Provided is a method of, in ladle refining treatment of a molten steel, accurately estimating the molten steel temperature after the ladle refining treatment. An operation method of ladle refining treatment by which ladle refining treatment of a molten steel is performed while continuously measuring a molten steel temperature during operation of the ladle refining treatment of the molten steel comprises setting a time earlier than a scheduled ending time of the ladle refining treatment in a continuous measurement period of the molten steel temperature as a determination timing, and estimating the molten steel temperature at the scheduled ending time on the basis of a change with time of the molten steel temperature in continuous measured data of the molten steel temperature from a start of continuous measurement of the molten steel temperature to the determination timing.
Abstract: Disclosed is, as a high-strength steel plate of API X80 grade or higher with a thickness of 38 mm or more, a thick steel plate for structural pipes or tubes that exhibits high strength in the rolling direction and excellent Charpy properties at its mid-thickness part without addition of large amounts of alloying elements. The thick steel plate for structural pipes or tubes disclosed herein has: a specific chemical composition; a microstructure at its mid-thickness part that is a dual-phase microstructure of ferrite and bainite with an area fraction of the ferrite being less than 50%, and that contains ferrite grains with a grain size of 15 ?m or less in an area fraction of 80% or more with respect to the whole area of the ferrite; a tensile strength of 620 MPa or more; and a Charpy absorption energy vE?20+ C. at ?20° C. at the mid-thickness part of 100 J or more.
Abstract: A fine ratio measuring device that measures a ratio of fines adhering to the surface of a material in the form of lumps, the fine ratio measuring device includes: an illumination unit that illuminates the material in the form of lumps; a spectrometer that performs spectral analysis on light reflected from the material in the form of lumps to measure spectral reflectance; and an arithmetic device that extracts at least one feature quantity from the spectral reflectance measured by the spectrometer and computes the fine ratio from the extracted at least one feature quantity.
Abstract: A motor comprising a steel sheet used as a core material of the motor, wherein the steel sheet includes a composition including: by mass %, 0.010% or less of C; 2.0% to 7.0% of Si; 2.0% or less of Al; 0.05% to 1.0% of Mn; 0.005% or less of S; 0.005% or less of N; and balance Fe and inevitable impurities; the steel sheet includes a magnetic flux density changing area where a change ?B in magnetic flux density to a change ?H=50 A/m in a magnetic field, is equal to or higher than 0.50 T; a thickness of the steel sheet is 0.05 mm to 0.20 mm; and an eddy-current loss of the steel sheet, at 1000 Hz?1.0 T, is equal to or less than 0.55 of a total iron loss.
Abstract: A screw joint in which an efficient screw length of a joint portion is achieved. This screw joint is for an oil well pipe of an integral type and includes: (i) a pin that is provided with a male screw portion which is a male taper screw, at one end of a steel pipe; and (ii) a box that is provided with a female screw portion which is a female taper screw fitted to the male screw portion, at one end of the steel pipe, in which a structure, in which the pin and the box are in metal contact with each other to seal a fluid, is provided at least at one place of a seal portion on an outer peripheral surface side of a pipe end side of the pin and a seal portion on an inner peripheral surface side of a pipe end side of the box.
Abstract: Disclosed is an electrical steel sheet with an insulating coating formed by applying a surface-treatment agent to at least one surface of the electrical steel sheet and drying the surface-treatment agent, wherein the surface-treatment agent contains: certain trialkoxysilane and/or dialkoxysilane (A); a silane coupling agent (B) that does not contain a polymerizable unsaturated group in its structure; plate-like silica (C); a polymerizable unsaturated-group-containing compound (D); and water, within a range satisfying the following conditions (1) to (3): (1) a mass ratio (A/B) of (A) to (B) is from 0.05 to 1.00; (2) a content of (C) is 2 mass % to 30 mass % with respect to a total mass of (A) to (D) in the surface-treatment agent; and (3) a content of (D) is 2 mass % to 18 mass % with respect to the total mass of (A) to (D) in the surface-treatment agent.
October 13, 2020
January 5, 2023
JFE STEEL CORPORATION
Nobuko NAKAGAWA, Chiyoko TADA, Naoki MURAMATSU