Yokohama, Japan
Yokohama, Japan

JFE Holdings, Inc. is a corporation headquartered in Tokyo, Japan. It was formed in 2002 by the merger of NKK and Kawasaki Steel Corporation . At the time, NKK Corporation was Japan's second largest steelmaker and Kawasaki Steel was the third largest steelmaker.Both companies were major military vessel manufacturers during World War II.JFE's main business is steel production. It also engages in engineering, ship building, real-estate redevelopment, and LSi business. The company also operates several overseas subsidiaries, including California Steel in the United States, Fujian Sino-Japan Metal in China, and Minas da Serra Geral in Brazil. Other than steel, they are also known for products such as the bicycle tree.JFE Holdings is the fifth largest Steel maker in the world with revenue in excess of US$30 billion. JFE Holdings has several subsidiaries including JFE Engineering, JFE Steel and JFE Shoji.NKK and Siderca S.A. of Argentina established a seamless pipe joint venture by spinning off the seamless pipe division of NKK's Keihin Works in 2000. In November 2009, JFE agreed to partner with JSW Steel, India's third-largest steel producer, to construct a joint steel plant in West Bengal.Its shipbuilding unit, Universal Shipbuilding was created in 2002 when NKK Corporation a predecessor of JFE, merged its shipbuilding unit with that of Hitachi Zosen. In 2012, JFE merged its ship building unit, Universal Shipbuilding Corporation, with Marine United Inc. of IHI after discussion started in April 2008 to form Japan Marine United Corporation It would be Japan’s largest shipbuilder. Wikipedia.

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An ultrasonic flaw detection apparatus 1 includes: a ultrasonic flaw detection sensor head 11 installed downstream from a seam detection unit 13; a seam position calculation unit 14a that calculates a seam position and a bead cutting position of an electric resistance welded pipe P by using a thermal image of a welded seam portion captured by the seam detection unit 13; a bead cutting band detection unit 15 that is installed immediately before or immediately after the ultrasonic flaw detection sensor head 11 and that detects a bead cutting band of the electric resistance welded pipe P; a bead cutting position calculation unit 14c that calculates, based on the bead cutting band detected by the bead cutting band detection unit 15, a bead cutting position of the electric resistance welded pipe P; and a tracking movement amount calculation unit 14d that calculates a tracking movement amount of the ultrasonic flaw detection sensor head 11 by using the seam position and bead cutting position calculated by the seam position calculation unit 14a and the bead cutting position calculated by the bead cutting position calculation unit 14c.


A molten steel fluidity estimation method estimates fluidity of molten steel in a casting mold of a continuous casting machine in such a manner that a CPU 113 calculates, at positions where thermocouples 41 are arranged in the casting mold of the continuous casting machine, an error between temperature distribution of the molten steel that is measured by using the thermocouples 41 and temperature distribution of the molten steel that is calculated by using a physical model; applies an external force in the vicinity of a discharge opening of a nozzle that discharges the molten steel into the casting mold; and calculates the fluidity of the molten steel in a state in which the external force adjusted to compensate the error is applied.


Patent
Jfe Holdings | Date: 2017-05-17

Provided is a method of producing a galvannealed steel sheet, the production method being capable of achieving a favorable plated appearance and of suppressing reductions in tensile strength. This method of producing a galvannealed steel sheet has: a step wherein a steel strip is transported through the inside of an annealing furnace, in order through a heating zone that includes a direct-firing-type furnace, a soaking zone, and a cooling zone, and the steel strip is annealed; a step wherein, after being discharged from the cooling zone, the steel strip is hot-dip galvanized; and a step wherein the zinc-plating applied to the steel strip is heated and alloyed. The production method is characterized in that a mixed gas that includes a humidified gas and a dry gas is supplied to the inside of the soaking zone from at least one gas supply port that is provided to the height-direction lower half of the soaking zone, and in that the dew point measured in the height-direction upper fifth of the soaking zone and the dew point measured in the height-direction lower fifth are both -20-0 C.


Patent
Jfe Holdings | Date: 2017-09-20

Provided is a method for manufacturing a steel sheet coated with a zinc-based coating layer with which it is possible to remove an oxide on the surface of a zinc-based coating layer through contact with an alkaline aqueous solution and with which it is possible to prevent a problem related to surface appearance due to precipitates generated in an alkaline aqueous solution. The method for manufacturing a steel sheet coated with a zinc-based coating layer of the first invention to solve the problems described above is a method for manufacturing a steel sheet coated with a zinc-based coating layer having a reaction layer on the surface of the steel sheet, the method including: the method including bringing the steel sheet coated with a zinc-based coating layer into contact for 1.0 second or more with an alkaline aqueous solution containing one or more chelating agents selected from among sodium gluconate, sodium glucoheptonate, sodium citrate, tartaric acid, arabonic acid, galactonic acid, sorbit, mannite, glycerin, EDTA, and sodium tripolyphosphate in a total amount of 0.050 mass% or more and having a pH of 10.0 or more as a pre-treatment before a formation of the reaction layer, and forming the reaction layer being an oxide layer containing a crystal-structured substance expressed by Zn_(4)(SO_(4))_(1-x)(CO_(3))_(x)(OH)_(6)nH_(2)O.


To predict the iron loss of a non-oriented electrical steel sheet after shearing, a non-oriented electrical steel sheet is sheared to a certain width, and iron loss Wt(B_(0)) of the non-oriented electrical steel sheet after shearing is estimated according to a predetermined relational expression based on iron loss Wn(B_(1)) in a non-machining-affected zone in which no machining strain is introduced by the shearing and iron loss Wi(B_(2)) in a machining affected zone in which machining strain is introduced.


Patent
Tokushu Kinzoku Excel Co. and Jfe Holdings | Date: 2017-09-13

Provided is a high-carbon cold-rolled steel sheet having a thickness of less than 1.0 mm and capable of having good impact and hardness characteristics after a short solution treatment, and thereafter quenching and low-temperature tempering. A high-carbon cold-rolled steel sheet having a steel sheet chemical composition containing, in terms of mass%, C: 0.85-1.10%, Mn: 0.50-1.0%, Si: 0.10-0.35%, P: 0.030% or less, S: 0.030% or less, and Cr: 0.35-0.45%, and furthermore containing Nb: 0.005-0.020 mass% with the remainder being Fe and unavoidable impurities, having a steel sheet structure in which the average particle diameter (d_(av)) of carbide dispersed in the steel sheet is 0.2-0.7 (m) and the spheroidization ratio is 90% or higher, and having a thickness of less than 1.0 mm. Mechanical characteristics having an excellent impact characteristic in which the impact value is 5 j/cm^(2) or higher and a sufficient hardness characteristic within the range of 600-750 HV can thereby be manifested by a short solution treatment of 3-15 minutes, and thereafter quenching and low-temperature tempering.


Disclosed are a high-strength galvanized steel sheet and a method for producing the same, the high-strength galvanized steel sheet including a chemical composition containing, by mass %, C: 0.15% or more and 0.25% or less, Si: 0.50% or more and 2.5% or less, Mn: 2.3% or more and 4.0% or less, P: 0.100% or less, S: 0.02% or less, Al: 0.01% or more and 2.5% or less, at least one element selected from Nb: 0.005% or more and 0.1% or less, Ti: 0.005% or more and 0.1% or less, V: 0.01% or more and 1.0% or less, and Mo: 0.005% or more and 2.0% or less, and the balance being Fe and inevitable impurities; and a steel-sheet microstructure containing, in terms of area fraction, a tempered martensite phase: 30% or more and 73% or less, a ferrite phase: 25% or more and 68% or less, a retained austenite phase: 2% or more and 15% or less, and other phases: 10% or less (including 0%), the other phases containing a martensite phase: 3% or less (including 0%) and a bainitic ferrite phase: less than 5% (including 0%), the tempered martensite phase having an average grain size of 8 m or less, the ferrite phase having an average grain size of 5 m or less, and the retained austenite phase having a C content less than 0.7% by mass.


Patent
Jfe Holdings | Date: 2017-09-20

Conditions for soft reduction are determined in accordance with the thickness of a slab strand so as to prevent center segregation from occurring in the strand due to an insufficient pressing rate or internal cracks from occurring in the strand due to an excessively high pressing rate. In the continuous casting method according to the invention, when a strand 10 having a thickness of 160 mm to 350 mm and a width of 1600 mm to 2400 mm is continuously cast while a region of the strand extending from a point of time at which a strand thickness-wise middle portion has a solid fraction of 0.1 to a point of time at which a strand thickness-wise middle portion has a solid fraction equivalent to a flow-limit solid fraction is pressed in a soft reduction zone 14 in which multiple pairs of strand support rolls are disposed, the strand thickness (D), the reduction rate (Z) of the soft reduction zone, and the strand withdrawal speed (V) satisfy a relationship expressed by expressions (1) and (2) below, where denotes a thickness coefficient (dimensionless), Do denotes a thickness (mm) of a standard strand at a position immediately below a mold, and and are coefficients determined by a width W (mm) of the strand:


Provided is a high-strength seamless steel pipe for oil country tubular goods having superior sulfide stress corrosion cracking resistance. The seamless steel pipe contains, by mass%, C: 0.20% to 0.50%, Si: 0.05% to 0.40%, Mn: 0.3% to 0.9%, Al: 0.005% to 0.1%, N: 0.006% or less, Cr: more than 0.6% and 1.7% or less, Mo: more than 1.0% and 3.0% or less, V: 0.02% to 0.3%, Nb: 0.001% to 0.02%, B: 0.0003% to 0.0030%, O (oxygen): 0.0030% or less, and Ti: 0.003% to 0.025%, in which Ti/N: 2.0 to 5.0 is satisfied, and the seamless steel pipe has a microstructure in which a volume fraction of a tempered martensitic phase is 95% or more; prior austenite grains have a grain size number of 8.5 or more; and in a cross-section perpendicular to a rolling direction, the number of nitride-based inclusions having a particle size of 4 m or more is 100 or less per 100 mm^(2), the number of nitride-based inclusions having a particle size of less than 4 m is 1000 or less per 100 mm^(2), the number of oxide-based inclusions having a particle size of 4 m or more is 40 or less per 100 mm^(2), and the number of oxide-based inclusions having a particle size of less than 4 m is 400 or less per 100 mm^(2).


Disclosed are a high-strength galvanized steel sheet and a method for producing the same, the high-strength galvanized steel sheet including a chemical composition containing, by mass %, C: 0.15% or more and 0.25% or less, Si: 0.50% or more and 2.5% or less, Mn: 2.3% or more and 4.0% or less, P: 0.100% or less, S: 0.02% or less, Al: 0.01% or more and 2.5% or less, and the balance being Fe and inevitable impurities; and a steel-sheet microstructure containing, by an area percentage basis, a tempered martensite phase: 30% or more and 73% or less, a ferrite phase: 25% or more and 68% or less, a retained austenite phase: 2% or more and 20% or less, and other phases: 10% or less (including 0%), the other phases containing a martensite phase: 3% or less (including 0%) and a bainitic ferrite phase: less than 5% (including 0%), the tempered martensite phase having an average grain size of 8 m or less, and the retained austenite phase having a C content less than 0.7% by mass.

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