Kawasaki Steel Corporation

Hirotake Ishitobi

Yasuhiro Kobayashi

Takafumi Suzuki

Michiro Komatsubara

Hiroi Yamaguchi

Yukio Inokuti

Ujihiro Nishiike

Shigeko Sujita

Norio Takahashi

Hisanao Nakahara

Yasuyuki Hayakawa

Mitsumasa Kurosawa

Masaki Kawano

Takahiro Kan

Katsuo Iwamoto

Yoshinori Anabuki

Ujihiro Nishike

Masayuki Sakaguchi

Toshikuni Tanda

Shiqeko Sujita

Tikara Kami

Kazuo Kawamura

Yutaka Kosaka

Michio Komatsubara

Keisuke Kotani

Michiro Komatsuhara

Kazuma Yonezawa

Ujiihiro Nishiike

Producing a grain oriented silicon steel sheet by controlling physical properties of the oxides layer, formed in decarburization annealing, in the surface layer of a steel sheet. A silicon compound is adhered to the surface of steel sheet before the decarburization annealing in an amount ranging from about 0.5 to 7.0 mg per square meter, expressed as Si, and the atmosphere of an earlier portion of the temperature holding process is adjusted to a ratio of steam partial pressure to the hydrogen partial pressure of less than about 0.7, and the atmosphere of the temperature rising process up to the temperature holding process is adjusted to an atmospheric composition lower than the atmospheric composition of the earlier portion of the temperature holding process, and the atmosphere of a later part of the temperature holding process is adjusted to an atmospheric composition lower than the atmospheric composition of the earlier part of the temperature holding process and in a range from about 0.005 to 0.2.

Process for producing grain oriented silicon steel sheet and

Process for producing grain oriented silicon steel sheet, and

A method for producing a grain-oriented silicon steel sheet in the coil shape having high magnetic induction and including AlN and MnSe as principal inhibitors is disclosed. In a series of processes for producing a grain-oriented silicon steel sheet, the oxide content on the steel sheet surface is controlled within a range of about 0.02 to 0.10 g/m.sup.2 before the temperature elevation phase of a decarburization annealing process, and the ratio of the steam partial pressure to the hydrogen partial pressure is controlled within a range of about 0.2 to 0.65 at a steel sheet surface temperature ranging from about 500.degree. to 750.degree. C. during the temperature elevation phase in a decarburization annealing process. The method promotes stable secondary recrystallized grain formation even in different coils or at different places in the same coil, such that fluctuation of magnetic properties is depressed.

Method for making grain-oriented silicon steel sheet having excellent

A method for controlling oxygen deposition on steel sheets. The oxygen deposition value of a steel sheet measured after decarburization annealing remains at a constant value by controlling, in the decarburization annealing line for the steel sheet, the electrolytic electricity density in electrolytic degreasing equipment included in the decarburization annealing line.

Method of controlling oxygen deposition during decarbutization annealing

In grain oriented silicon steel sheets containing MnSe as a main inhibitor, an iron loss is reduced by increasing the magnetic flux density and realizing the thinning of product thickness and fine division of crystal grains while utilizing the stability of secondary recrystallization as a merit of such a sheet. In this case, 0.02-0.30% of Cu is added to a slab of the above grain oriented silicon steel, and particularly the decarburization annealing and/or the final finish annealing are carried out under particular conditions.

Method of producing grain oriented silicon steel sheets having less iron

A silicon-containing steel sheet having a low iron loss has such a crystal structure that crystal grains having an inclination angle of {110} face of not more than 10.degree. with respect to the sheet surface are included in an amount of not less than 80 vol % and exhibit a graining surface pattern in which boundaries of these crystal grains form stepwise difference or groove of not less than 0.4 .mu.m as a maximum height. This sheet is produced by subjecting a grain oriented silicon steel sheet after final annealing to a magnetically smoothening treatment by electrolysis in an squeous solution containing at least one of water soluble halides.

Silicon steel sheets having low iron loss and method of producing the

A grain oriented electromagnetic steel sheet having a very low iron loss is obtained by subjecting a surface of base metal in the sheet after finish annealing to a particular mechanical polishing and has a surface roughness having a center-line average roughness of not more than 0.3 .mu.m after the polishing and the number of abrasive grains embedded in a layer just beneath polished surface of not more than 20,000 grains/cm.sup.2.

Grain oriented electromagnetic steel sheets having a very low iron loss

A surface coated steel strip having improved corrosion resistance, comprising a steel strip, a zinc alloy (e.g. Zn-Ni, Zn-Mn, Zn-Co, etc.) layer electroplated on the strip, a chromate film formed on the zinc alloy layer in a weight of 2 to 60 mg/m.sup.2, and a polyethylene coating cured to the chromate film and weighing 0.3 to 5 g/m.sup.2 is prepared by applying a chromate solution to the zinc alloy plated strip and drying it into the chromate film, and applying an aqueous composition of a carboxylated-polyethylene resin, a melamine resin, and colloidal silica to the chromated strip and drying and curing the composition into the coating at elevated temperatures of at least 130.degree. C.

Surface treatment of zinc alloy electroplated steel strips

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Chiba, Japan

Hirotake Ishitobi