Nippon Steel Corporation

Yoshiaki Shimoyama

Kunisuke Miyoshi

Takeshi Kubota

Shigenobu Koga

Morio Shiozaki

Yoshitaka Hiromae

Hisanobu Nakayama

Yasukazu Mori

Ichiro Tachino

Nobuoki Ishihara

Shouzaburo Nakashima

Katsuyki Ohba

Hiroyuki Kimura

Katuyuki Oba

Takeaki Takeshita

Mitsuaki Kawashima

Takashi Masuda

In a conventional process for producing a semi-processed non-oriented electrical steel sheet, the silicon or aluminum content of a hot-rolled steel strip is high, especially in the case of producing a high-grade electrical sheet which has a low watt loss. However, a high silicon or aluminum content disadvantageously results in a decrease in the magnetic flux density. A decrease in the watt loss and an increase in the magnetic flux density in semi-processed non-oriented electrical steel sheets as compared with conventional high-grade semi-processed non-oriented electrical steel sheets can be achieved by making the silicon content, which increases resistivity, low, i.e. from 0.1 to 1.0%, and the manganese content, which is effective for improving the texture, high i.e. from 0.75 to 1.5% and by subjecting the starting material, having a low silicon content, and a high manganese content to an appropriate production process for controlling texture.

Process for producing a semi-processed non-oriented electrical steel

Method for the production of a single oriented silicon steel sheet having excellent magnetic property which comprises providing a silicon steel slab containing 0.010.about.0.10% C, 2.5.about.4.5% Si, 0.02.about.0.15% Mn, and a total of 0.008.about.0.080% of one or two of S and Se, hot rolling the silicon steel slabing to sheet, and subjecting the hot rolled sheet to a two-step annealing procedure wherein the first half is at a temperature of 1000.degree..about.1200.degree. C. and the latter half at 750.degree..about.980.degree. C., and to at least two cold rolling steps.

Method for the production of oriented silicon steel sheet having

In the production of non-oriented electrical steel sheets, it has been attempted to decrease the watt loss, e.g., by adding Sn to silicon steels, but in such a case the relationship between the watt loss and the magnetic flux density falls within the curves 1 and 1' in FIG. 1. The addition of boron is therefore unsatisfactory for meeting the recent demand for improving the magnetic properties of a non-oriented electrical steel sheet over those indicated by the curve 3. In the present invention, the combined addition of Sn and B and/or sol. Al results in the development of (110) and (100) textures, which are desirable for the magnetic properties. A non-oriented electrical steel sheet according to the present invention consists of:

Non-oriented electrical steel sheet having a low watt loss and a high

Process for producing a non-oriented electromagnetic steel sheet having

The present invention relates to a process for producing an electrical steel sheet. In order to prevent aging deterioration of the electrical steel sheet, the carbon content of the steel for the sheet should be reduced to an extremely low level, e.g., 0.0030% or less. However, when molten steel was subjected to vacuum-degassing and continuous-casting procedures to prepare steel for a electrical steel sheet in a prior art, although a desired carbon content of the molten steel was ensured at the degassing stage, the carbon content of the steel sometimes exceeded the desired level at the slab range. In the present invention, the prior art problem is solved by carrying out the degassing procedure under conditions in which the ultimate degree of vacuum in the degassing vessel is 1.0 mmHg or less, the rate of inert gas blown per gas-blowing orifice is from 30 to 150 Nl/min, and the final carbon content of the molten steel is 0.0030% or less and by using means contacting the melt during the continuous-casting procedure, the carbon content of said means being 3.0% or less.

Process for producing steel for an electrical steel sheet

A non-oriented magnetic material consisting essentially of .ltoreq.0.065% C, .ltoreq.0.10% Al, 0.31 to 3.15% Si, .ltoreq.0.020% O, .ltoreq.0.01% N and B present in such amounts that the ratio of B/N is in the range of 0.5 to 2.50. The non-oriented magnetic material of this invention is produced by hot rolling a material of the above composition, subjecting the hot-rolled sheet to at least one cold-rolling step with intermediate annealing followed by a continuous annealing step and optionally a reannealing step to produce a non-oriented magnetic material.

Non-oriented electric iron sheet and method for producing the same

A non-oriented silicon steel sheet with a low watt loss value as well as uniform magnetic properties which contains 1.5-3.5% Si, an exceedingly low C content, and a low soluble Al content, and has a ratio of B to N in the range of 0.4 to 2.0, and further contains at least one rare earth element.

Non-oriented silicon steel sheet with stable magnetic properties

In the continuous casting of slabs for use in manufacturing grain-oriented electrical steel sheet and strip, the slag covering the molten steel for casting the slabs is adjusted in its composition to maintain the ratio of Al.sub.2 O.sub.3 to SiO.sub.2 at not less than 0.25, whereby the slabs continuously cast from the molten steel are made free from variation in Al or Al and S content in the direction of casting.

Method for continuously casting slab for manufacturing grain-oriented

Process for producing non-directional electric steel sheets free from ridging, comprising preparing slabs by continuous casting from molten steel comprising not more than 0.04% C, 1.5 to 4.0% Si, not more than 1.0% Al, the balance being Fe and unavoidable impurities, hot rolling, cold rolling and annealing the slabs, characterized in that the slab is subjected to breaking-down with a reduction rate between 10 to 70% in the sheet thickness direction at a temperature between 1000.degree. and 1300.degree. C, and subsequently the required treatments are done.

Process for producing non-directional electric steel sheets free from

A method for manufacturing non-oriented electrical steel sheet and strip having no ridging characterized in that, non-oriented electrical steel sheet and strip is manufactured by casting molten silicon steel into a slab, hot-rolling, cold-rolling and annealing, said molten silicon steel, being controlled so as to give a composition, at the time of hot-rolling, comprising C &lt;0.06%, Si 1.5 - 4.0% and Al &lt; 1.0%, with the relation Si + Al &gt; 2.0% and also C .gtoreq. 1/100 [(Si + Al) - 0.75]% with the remainder being iron and unavoidable impurities.

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Kitakyushu, Japan

Yoshiaki Shimoyama