Jfe Steel Corporation

Toray Industries, Inc.

Hirokazu Sugihara

Soshi Yoshimoto

Satoshi Ueoka

Yoshimichi Hino

Yuiko Ehashi

Yoshitsugu Suzuki

Yoshiyasu Kawasaki

Hiroyuki Fukuda

Yasunobu Nagataki

Yukihiro Shingaki

Takashi Kuroki

Masanori Takenaka

Norichika Aramaki

Akitoshi Matsui

Nobuo Nishiura

Fujio Tanaka

Ichiro Itagaki

Mai Miyata

Hiromi Takarada

Tomohiro Hashimukai

Ryo Matsuo

Tsutomu Sugiyama

Shuhei Irie

Sho Kokufu

Kenichi Osuka

Shunichi Nakamaru

A grain oriented electrical steel sheet is produced by heating a steel slab containing, by mass %, C:0.02-0.10%, Si:2.0-5.0%, Mn:0.01-1.00%, sol. Al:0.01-0.04%, N:0.004-0.020% and S+Se:0.002-0.040% to a temperature of higher than 1280° C., and subjecting the sheet to a hot rolling, a hot-band annealing, a single cold rolling or two or more cold rollings having an intermediate annealing between each cold rolling and a primary recrystallization annealing combined with a decarburization annealing, applying an annealing separator onto a steel sheet surface, and subjecting the sheet to a finish annealing and a flattening annealing, a rapid cooling is conducted at an average cooling rate of not less than 200° C./s from 800° C. to 300° C. in the cooling process from a maximum achieving temperature in at least one annealing of the hot-band annealing and the intermediate annealing.

Method for producing grain-oriented electrical steel sheet

When a grain-oriented electrical steel sheet is produced by heating a steel slab containing, by mass %, C: 0.020 to 0.10%, Si: 2.0 to 4.0%, Mn: 0.005 to 0.50%, Al: less than 0.010%, N, S and Se: less than 0.0050% each to a temperature of not higher than 1280° C., subjecting slab to hot rolling, hot-band annealing, single cold rolling or two or more cold rollings having intermediate annealing between each cold rolling and a primary recrystallization annealing combined with decarburization annealing, applying annealing separator onto steel sheet surface, and subjecting steel sheet to finish annealing and a flattening annealing, a rapid cooling is conducted at an average cooling rate of not less than 200° C./s from 800° C. to 300° C. in cooling process from maximum achieving temperature in at least one of hot band annealing and intermediate annealing, whereby grain-oriented electrical steel sheet having excellent magnetic properties is stably produced.

A method for continuously casting steel capable of reducing center segregation that occurs in a slab. In a section in a continuous casting machine in a slab withdrawal direction, a section from a start point at which the average value of solid phase ratios along a thickness direction at a widthwise center of a slab is within a range of 0.4 or more and 0.8 or less to an end point at which the average value of solid phase ratios along the thickness direction at the widthwise center of the slab is greater than the average value of solid phase ratios at the start point and is 1.0 or less is set as a first section. The slab is cooled by water in the first section at a water flow rate per surface area of the slab within a range of 50 L/(m&#xd7;min) or more and 2,000 L/(m&#xd7;min) or less.

Method for continuously casting steel

Provided are a method for measuring the magnetic transformation rate of a steel sheet in an annealing furnace and an apparatus for measuring the same, and a continuous annealing process and a continuous galvanizing process which utilize the method and the apparatus. One such method includes delivering an alternating-current driving signal to the surface of the steel sheet by using an air-core driving coil having a size larger than, a width of the steel sheet, measuring the driving signal reflected by the steel sheet by using air-core receiving coils having a size larger than the width of the steel sheet, and determining the magnetic transformation rate of the steel sheet by using a measurement processing unit based on a distance between the steel sheet and the driving coil which has been corrected by using the measured values of the driving signal obtained by using the receiving coils.

Method for measuring magnetic transformation rate of steel sheet in annealing furnace, apparatus for measuring the same, continuous annealing process, and continuous galvanizing process

Wear for measuring biological signal

A rapid-cooling quenching apparatus in which a high-temperature metal sheet is dipped and cooled in a liquid and a rapid-cooling quenching method for a steel sheet are provided. The rapid-cooling quenching apparatus includes a water tank containing the liquid in which the metal sheet is dipped, a jetting device having a plurality of nozzles through which the liquid is jetted onto front and back surfaces of the metal sheet and at least some of which are placed in the liquid in the water tank, and a pair or a plurality of pairs of restraining rolls which are placed between an entrance-side end of the jetting device and an exit-side end of the jetting device and restrain the metal sheet, in which nozzles nearest to the restraining rolls are inclined toward the restraining rolls from a horizontal plane in the jetting device.

Rapid-cooling quenching apparatus and rapid-cooling quenching method

The invention proposes a method for heating a steel sheet wherein the generation of buckling can be prevented regardless of presence or absence of rolls restraining the steel sheet by antecedently heating the widthwise central portion of the steel sheet with a solenoid type induction heating coil having a convex form projected onto the surface of the steel sheet toward an upstream side in rapidly heating the continuously traveling steel sheet, whereby an isotherm of the steel sheet in the heating is a convex form toward the upstream side, so that a large wrinkle is generated on the steel sheet, and also proposes a heating apparatus used in this method.

Method and apparatus for heating steel sheet

Provided is a hot-rolled steel sheet having a composition containing 0.04 mass percent to 0.20 mass percent C, 0.7 mass percent to 2.3 mass percent Si, 0.8 mass percent to 2.8 mass percent Mn, 0.1 mass percent or less P, 0.01 mass percent or less S, 0.1 mass percent or less Al, and 0.008 mass percent or less N, the remainder being Fe and inevitable impurities. Internal oxides containing one or more selected from the group consisting of Si, Mn, and Fe are present at grain boundaries and in grains in a base metal. The internal oxides present at the grain boundaries in the base metal are located within 5 &#x3bc;m from the surface of the base metal. The difference between the depths at which the internal oxides are formed in the cross direction of the steel sheet is 2 &#x3bc;m or less.

Hot-rolled steel sheet for high-strength galvanized steel sheet or high-strength galvannealed steel sheet and method for manufacturing the same (as amended)

A hot rolled steel sheet cooling apparatus includes a gradual cooling headerincluding a rod-like cooling water nozzlefor gradual cooling and a rapid cooling headerincluding a rod-like cooling water nozzlefor rapid cooling such that the headers constitute a cooling unit. The cooling unitincludes an elevating unitcapable of moving upward and downward in unison with the cooling unit. In cooling the upper surface of a hot rolled steel sheet (hot rolled steel strip or steel plate), uniform and stable cooling is achieved while both of high cooling rate and low cooling rate are ensured.

Hot rolled steel sheet cooling apparatus

Growing community of inventors

Tokyo, Japan

Hirokazu Sugihara