Nkk Corporation

Nippon Kokan Kabushiki Kaisha

Nippon Mining Co., Ltd.

Akihiko Nishimoto

Yoshihiro Hosoya

Toshiaki Urabe

Kunikazu Tomita

Masaharu Jitsukawa

Kazuhide Nakaoka

Akira Sakamoto

Masayuki Kinoshita

Masahiro Tsuji

Kenzi Araki

Yoshiharu Miyawaki

Susumu Kawauchi

Haruo Kubotera

Morinori Kamio

Koji Iwase

Osamu Nozoe

Kozi Iwase

Jun Ono

Yoshihara Hosoya

Hideki Isayama

Toskhiaki Urabe

Method of making non-oriented electrical steel sheets

Method of making non-oriented electrical steel sheets having excellent

A method for producing a non-oriented electrical steel sheet with precise thickness and homogeneous magnetic property comprising the steps of: making a steel ingot which has: 0.01 wt. % or less C, 0.003 wt. % or less N, 0.01 to 1.0 wt. % Mn, Al and Si satisfying, in wt. %, the formulas of: ##EQU1## provided that (Si %) represents the Si (wt. %) and (Al %) represents Al content (wt. %), and the balance being Fe and inevitable impurities to produce a steel slab; hot-rolling the slab at a finishing temperature of 700.degree. to 900.degree. C. into a steel strip and coiling the hot rolled strip; and cold-rolling the hot-rolled strip into a cold-rolled strip, followed by annealing the cold-rolled strip.

Method for producing non-oriented steel sheets

For enabling the manufacture of non-oriented steel strips by HDR, the amounts of AlN and MnS which precipitate on the way of HDR are decreased to such a level that they do not affect the magnetic properties by regulating the Al and S contents, and further unavoidable precipitating nitrides are precipitated as coarse BN. With regard to the steel composition, the amounts of C, Si and P are not only regulated, but also the amounts of Mn, Al, S and N are regulated from the above standpoint, and a proper amount of B is added if required. In addition, in regard to treatment conditions, in order to secure necessary finishing and coiling temperatures, the lower limit of the slab temperature at the starting time of HDR is specified. Moreover, to secure precipitation of BN and recrystallization of a ferrite structure, the lower limits of the finishing and coiling temperatures are specified. Furthermore, to secure the magnetic properties after cold rolling, the strips are finally continuously annealed at the determined temperature.

Method of making non-oriented magnetic steel strips

For enabling the making of non-oriented magnetic steel strips by direct rolling, the amounts of AlN and MnS which precipitate on the way of the direct rolling are decreased to such a level that they do not affect the magnetic properties by regulting the Al and S amounts, and further unavoidable precipitating nitrides are precipitated coarsely as BN. With regard to the steel composition, the amount of C, Si and P are not only regulated, but also the amounts of Mn, Al, S and N are regulated from the above standpoint, and a proper amount of B is added if required. In addition, in regard to treatment conditions, in order to secure necessary finishing and coiling temperatures, the lower limit of the slab temperature at the starting time of the direct rolling is specified. Moreover, to promote refining of ferrite, the upper limit of the finishing temperature is specified, and also to prevent non-uniform recrystallization after coiling, the upper limit of the coiling temperature is specified. Furthermore, to secure satisfied magnetic properties, the annealing of the hot rolled strip is performed under specific conditions determined by a soaking temperature and a soaking time. In addition, to secure the magnetic properties of the cold rolled strip, the strip is finally continuously annealed at determined temperatures.

A method for producing non-oriented electrical steel sheets comprising the steps of:

A method for producing cold-rolled steel sheets which comprises the steps of: producing slabs containing 0.001-0.003 wt. % C, 0.004 wt. % or less N and 0.03-0.20 wt. % P, providing that P(wt. %).times.N(wt. %).ltoreq.3.times.10.sup.-4 wt. % is satisfied; hot-rolling the slabs into hot-rolled steel strips; cold-rolling the hot-rolled steel strips at 60-95% reduction ratio into cold-rolled steel strips; and annealing continuously the cold-rolled strips at temperature of recrystallization temperature to Ac.sub.3 transformation point temperature. The slabs further include 0.0005-0.0030 wt. % B. The hot-rolling is performed at finishing temperature ranging Ar.sub.3 transfromation point to Ar.sub.3 transformation +100.degree. C., at cooling temperature of 750.degree. C. and less.

Method for producing cold-rolled steel sheet

Pickling method for electrical steel bands

Method of making non-oriented silicon steel sheets having excellent

An Al-killed cold-rolled steel sheet with excellent demagnetization characteristics is provided which is substantially consisted of 0.005% or less C; from 0.05 to 0.50% Mn; 0.010% or less S; from 0.01 to 0.08% Sol.Al; 0.0050% or less N; wherein Mn %/S %.gtoreq.7 and (Sol.Al % - 0.003%)/N %.gtoreq.6; and the remainder iron and inevitable impurities. A shadow mask made of such Al-killed cold-rolled steel sheet and a color television receiver using the same exhibit a very excellent function. A preferred process for producing such an Al-killed cold-rolled steel is also provided, said process being characterized in first obtaining a steel or a specific composition by the use of a vacuum degassing apparatus and then subjecting the steel to sequential steps of hot rolling, cold rolling, decarburization-annealing, and cold rolling.

Al-killed cold-rolled steel sheet with excellent demagnetization

A method for manufacturing a high-strength cold-rolled steel strip excellent in press-formability, which comprises the steps of: preparing a slab of an aluminum-killed steel consisting essentially of, in weight percentage:

Method for manufacturing high-strength cold-rolled steel strip excellent

Growing community of inventors

Tokyo, Japan

Akihiko Nishimoto