Jfe Steel Corporation

Ginza Maronie P.c.

Yukihiro Shingaki

Takeshi Imamura

Yasuyuki Hayakawa

Toshito Takamiya

Hiroshi Matsuda

Tomoyuki Okubo

Hiroi Yamaguchi

Ryuichi Suehiro

Takashi Terashima

Hirotaka Inoue

Yuiko Wakisaka

Yusuke Shimoyama

Makoto Watanabe

Hideyuki Takahashi

Kunihiro Senda

Takeshi Omura

Minoru Takashima

Mineo Muraki

Masanori Takenaka

Tadashi Nakanishi

Takumi Umada

Soshi Yoshimoto

Hirokazu Sugihara

Noriko Makiishi

Yuiko Ehashi

Takeshi Murai

Akifumi Harada

Provided is a method of manufacturing a grain-oriented electrical steel sheet with which a grain-oriented electrical steel sheet with excellent magnetic properties and little variation in iron loss in the longitudinal direction of a coil can be stably manufactured. The method includes subjecting a steel slab to hot-rolling and optionally to annealing, then performing cold rolling once or twice or more to obtain a cold-rolled sheet with a final sheet thickness, and then subjecting the cold-rolled sheet to decarburization annealing and then secondary recrystallization annealing, where immediately before final cold rolling, a steel sheet is heated at a heating rate of 100° C./s or more to a heating temperature of 100° C. or higher and 350° C. or lower, and a time from when the steel sheet reaches the heating temperature to when it is bitten in a first pass of final cold rolling is set to within 5 seconds.

Method of manufacturing grain-oriented electrical steel sheet

Disclosed is a grain-oriented electrical steel sheet capable of obtaining excellent magnetic properties stably over the entire coil length. A grain-oriented electrical steel sheet includes: a chemical composition containing, in mass %, C: 0.005% or less, Si: 2.0% to 4.5%, and Mn: 0.01% to 0.5%, and, in mass ppm, N: 20 ppm or less, each of Se, Te, and O: less than 50 ppm, S: less than 30 ppm, and acid-soluble Al: less than 40 ppm, and Ti: less than 30 ppm, of which 5 ppm or more and 25 ppm or less is acid-soluble Ti, with the balance being Fe and inevitable impurities; and precipitates containing Ti and N with a grain size of 200 nm or more at a frequency of 0.05 grains/mmor more.

Grain-oriented electrical steel sheet and method of producing same

In a method of producing a grain-oriented electrical steel sheet comprising subjecting a steel slab containing no inhibitor-forming components to hot rolling, cold rolling, primary recrystallization annealing working also as decarburization and to final annealing causing secondary recrystallization after applying an annealing separator on the surface, the final cold rolling for cold rolling the steel sheet to the final thickness uses a warm rolling with a tandem rolling mill at a total rolling reduction of not less than 80% at 150 to 280° C. and is performed by extending a pass line length of the steel sheet between the stands so that T satisfies T≥1.3×L/V, where an distance between the stands is defined as L(m), a speed of the steel sheet passing between the stands is defined as V (mpm), and a pass time during which the steel sheet passes between the stands is defined as T(min).

Method for producing grain-oriented electrical steel sheet and cold-rolling facility

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.

Method for producing grain-oriented electrical steel sheet

A nitriding apparatus for manufacturing a grain-oriented electrical steel sheet is provided. The nitriding apparatus includes: a nitriding gas supply pipe for introducing gas including at least ammonia or nitrogen; and a nitriding treatment portion for successively performing high-temperature nitriding and low-temperature nitriding in nitriding treatment. The nitriding treatment portion includes a high-temperature treatment portion for performing the high-temperature nitriding and a low-temperature treatment portion for performing the low-temperature nitriding, and the nitriding gas supply pipe to the high-temperature treatment portion includes a cooling device.

Nitriding apparatus for manufacturing a grain-oriented electrical steel sheet

Provided is a surface treatment facility in which both surfaces of a material are subjected to continuous film deposition by PVD as the material is conveyed in the longitudinal direction, wherein flutter of the material subjected to coating can be suppressed. This surface treatment facility comprises a chamber configured to continuously deposit a film by PVD on both surfaces of a material as the material is conveyed in the longitudinal direction through the chamber; a conveyance mechanism for conveying the material subjected to coating; a blowing mechanism for blowing film-forming gas in the longitudinal direction on both sides of the material present in the chamber; and has an X/Y ratio within a range of 0.4 to 3.0 where X is the film-forming gas blowing speed, and Y is the conveyance speed of the material subjected to coating, and where the unit of measurement of X and Y is m/min.

Surface treatment facility

Provided is a method for nitriding a grain-oriented electrical steel sheet which is very useful in obtaining excellent magnetic properties with no variation, that enables generating glow discharge between positive electrodes and negative electrodes disposed in a nitriding zone and irradiating the generated plasma to a strip to perform appropriate nitriding.

Method for nitriding grain-oriented electrical steel sheet

A grain-oriented electrical steel sheet that includes a base coating with a high TiN ratio advantageous for the application of tension to the steel sheet and has excellent magnetic property is provided. The grain-oriented electrical steel sheet includes: a base coating having a peak value PTiN of TiN in the form of osbornite, observed in a range of 42&#xb0;&#x3c;2&#x3b8;&#x3c;43&#xb0; and a peak value PSiOof SiOin the form of cristobalite, observed in a range of 23&#xb0;&#x3c;2&#x3b8;&#x3c;25&#xb0; of both more than 0 and satisfying a relationship PTiN&#x2265;PSiO, in thin-film X-ray diffraction analysis; and an iron loss Wof 1.0 W/kg or less.

Grain-oriented electrical steel sheet and method of manufacturing same

In a grain-oriented electrical steel sheet manufacturing process of processing a steel slab having a predetermined composition to a final sheet thickness and then performing primary recrystallization annealing and nitriding treatment, the nitriding treatment is performed in at least two stages of temperatures including high-temperature nitriding and low-temperature nitriding, and a residence time in the high-temperature nitriding is 3 seconds or more and 600 seconds or less. In this way, nitrogen is efficiently diffused into the steel of the steel sheet before secondary recrystallization to precipitate AlN. Such a method can manufacture a grain-oriented electrical steel sheet having excellent magnetic property.

Method for manufacturing grain-oriented electrical steel sheet, and nitriding apparatus

The disclosure contains, in mass % or mass ppm: C: 0.005% or less, Si: 2.0% to 5.0%, Mn: 0.01% to 0.5%, sol.Al: 10 ppm or less, N: 15 ppm or less, S and Se: each 10 ppm or less, and three or more selected from Sn, Sb, Cr, P, Mo and B whose contents satisfy a relational expression of 0.16&#x2264;[% Sn]+[% Sb]+[% Cr]+2&#xd7;[% P]+[% Mo]+[% B]&#x2264;0.50, the balance being Fe and inevitable impurities, where a number of times of repeated bending in a bend test is 10 or more.

Grain-oriented electrical steel sheet and method for manufacturing the same

When a steel sheet containing Si: 2-5 mass % after cold rolling is subjected to a primary recrystallization annealing and a finishing annealing for secondary recrystallization to form a grain-oriented electrical steel sheet, the primary recrystallization annealing is performed by rapid heating in the heating process and temperature keeping treatment at a certain temperature in the course of the heating to thereby obtain a grain-oriented electrical steel sheet having plural peaks in a distribution of misorientation angle between crystal orientation of secondary recrystallized grains and Goss orientation, wherein misorientation angle of the second smallest peak among the plural peaks is preferably not less than 5&#xb0; and a grain size of secondary recrystallized grains is not more than 15 mm.

Grain-oriented electrical steel sheet

A grain-oriented electrical steel sheet that includes a base coating with a high TiN ratio advantageous for the application of tension to the steel sheet and has excellent magnetic property is provided. The grain-oriented electrical steel sheet includes: a base coating having a peak value PTiN of TiN in the form of osbornite, observed in a range of 42&#xb0;&#x3c;2&#x3b8;&#x3c;43&#xb0; and a peak value PMgSiOof MgSiOin the form of forsterite, observed in a range of 35&#xb0;&#x3c;2&#x3b8;&#x3c;36&#xb0; of both more than 0 and satisfying a relationship PTiN&#x2265;PMgSiO, in thin-film X-ray diffraction analysis; and an iron loss Wof 1.0 W/kg or less.

Provided is a method for nitriding a grain-oriented electrical steel sheet which is very useful in obtaining excellent magnetic properties with no variation by immersing a strip in a molten salt bath after cold rolling and before secondary recrystallization annealing during a production process of a grain-oriented electrical steel sheet, to subject the strip to continuous nitriding to uniformly disperse inhibitor forming elements over the full length and full width of the strip.

Method and device for nitriding 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.

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Kurashiki, Japan

Yukihiro Shingaki