Nippon Steel Corporation

Kenzo Iwayama

Yasunari Yoshitomi

Isao Iwanaga

Katsuro Kuroki

Hidehiko Sumitomo

Kenichi Miyazawa

Osamu Tanaka

Toshiaki Mizoguchi

Tsunehiro Shimizu

Takashi Sato

Shozaburo Nakashima

Takeo Nagashima

Kunihide Takashima

Kenichi Yakashiro

Akira Amemura

A method of producing permalloy cores comprising the steps of coating at least one surface of permalloy strip with a slurry consisting of water containing 1 to 5 percent by weight of magnesium hydroxide (Mg(OH).sub.2) powder and the addition of one or more selected from a binder, a thickening agent and a defoaming agent and drying said coating, slitting the permalloy strip thus covered with a coating that when dry is 0.1 to 50 .mu.m thick, more preferably 0.5 to 10 .mu.m thick, and contains not less than 50 percent by weight Mg(OH).sub.2, and more preferably not less than 80 percent by weight Mg(OH).sub.2, as the main constituent, to a final width, or first to an intermediate width if necessary, winding or punching the final width strip to obtain wound or laminated punched cores, and subjecting the core materials to magnetization annealing.

Method of producing permalloy cores

Process for preparing rollable metal sheet from quenched solidified thin

A method of producing Fe-Ni system high permeability alloy comprising the steps of obtaining cast steel sheet 0.3 to 7 mm thick by direct casting of a steel melt containing 35 to 85% by weight of nickel with the balance of iron and unavoidable impurities, forcibly cooling the sheet from solidification to 1200.degree. C. at a cooling rate of at least 75.degree. C./s, and cold-rolling the sheet at a reduction ratio of at least 20%.

Method of manufacturing high permeability Fe-Ni system alloy

Disclosed is a process for preparing a thin grain oriented electrical steel sheet having a final thickness of 0.05 to 0.25 mm from a silicon steel cast strip having a thickness of 0.2 to 5 mm and directly obtained from the molten steel by the synchronous continuous casting machine, in which the speed of movement of the strand relative to the inner wall surface of the casting mold is the same, and by which the traditional hot rolling process can be omitted, comprising 0.050 to 0.120% by weight of C, 2.8 to 4.0% by weight of Si and 0.05 to 0.25% by weight of Sn, wherein the starting silicon cast strip further comprises up to 0.035% by weight of S and 0.005 to 0.035% by weight of Se, with the proviso that the total amount of S and Se is in the range of 0.015 to 0.060% by weight, 0.050 to 0.090% by weight of Mn, with the proviso that the Mn content is in the range of {1.5.times.[content (% by weight) of S+content (% by weight) of Se]} to {4.5.times.[content (% by weight) of S+content (% by weight) of Se]} % by weight, 0.0050 to 0.0100% by weight of N, and {[27/14].times.content (% by weight) of N+0.0030} to {[27/14].times.content (% by weight) of N+0.0150} % by weight of acid-soluble Al.

Process for preparation of thin grain oriented electrical steel sheet

A method of producing a grain oriented electrical steel sheet having a high magnetic flux density comprises the steps of continuously rapid quench solidifying a molten steel essentially consisting of 0.03 to 0.10% of C, 2.5 to 4.5% of Si, 0.02 to 0.15% of Mn, 0.01 to 0.04% of Al acid soluble by weight and the remainder substantially Fe, to obtain a thin strip, subjecting the thin strip to cold rolling one or two or more stages, with an annealing therebetween, decarburization annealing, and finishing annealing wherein the content of S in the molten steel is 0.01% or less the content of N in the molten steel is 0.003% or less, and sulfide and nitride are contained in the annealing separator for the finishing annealing.

Method of producing grain oriented electrical steel sheet having high

The present invention concerns a process for producing a grain-oriented electrical steel sheet by means of a rapid quench-solidification process, for example, a continuous casting by a twin roll strip caster. The feature of the present invention resides in quenching to solidify molten steels into a thin cast sheet of 0.7 to 3.0 mm thickness, at a cooling rate of greater than 50.degree. C./sec. in the central portion along the direction of thickness of the thin cast sheet, cooling the sheet at a cooling rate of greater than 10.degree. C./sec. in a temperature range between 1300.degree. to 900.degree. C. and then applying cold rolling for once or twice or more annealing the thin cast steel for a period between 30 seconds and 30 minutes in a temperature range between 950.degree. and 1,200.degree. C. and subsequently including intermediate annealing under a final cold rolling reduction rate of not less than 80%. In the present invention, precipitates that function as an inhibitor can finely be dispersed by adding 0.02 to 0.2% of Nb into the molten steel ingredients thereby to stably produce a grain-oriented electrical steel sheet of high magnetic flux density by means of a rapid quench-solidification process. Further, since a thin cast sheet of desired thickness within a range from 0.7 to 3.0 mm can be produced by the rapid quench-solidification process, the thin cast sheet can be cold rolled to a final thickness of less than 150 .mu.m by applying a cold rolling at a reduction rate optimum to magnetic properties, and an extremely thin grain-oriented electrical steel sheet of less than 150 .mu.m (0.15 mm) thickness can be produced in a simple production process and at a reduced cost, which so far has been remarkably difficult and expensive to produce.

Process for producing a grain-oriented electrical steel sheet by means

A method of producing grain-oriented electrical steel sheet with a very high magnetic flux density, is characterized by increasing the partial pressure of the N.sub.2 in the annealing atmosphere at the intermediate stage between the start and the finish of the secondary recrystallization, and by ensuring the temperature differential in the coil does not exceed 100.degree. C. during changes to the annealing atmosphere. In addition, the rate of temperature increase at the hottest part of the coil is kept to a maximum of 13.degree. C./hr at least part of the time the coolest part of the coil is between 850.degree. C. and 1100.degree. C.

Method for producing grain-oriented electrical steel sheet with very

In the production of a grain-oriented electrical steel sheet by utilizing an AIN main inhibitor and at least twice cold-rolling with a heavy final reduction, improved magnetic properties are stably obtained by controlling the cooling speed (R) in the cooling process of a hot-rolled sheet annealing (R.gtoreq.5.degree.C./sec from 600.degree.-200.degree. C.) and by inter-pass aging (50.degree.-500.degree. C. for 1 minute or more) during the first cold-rolling.

Process for producing a grain-oriented electrical steel sheet having

A thin-gauge (0.10-0.23 mm thick) grain-oriented electrical steel sheet is produced by a process characterized by a decarburization which is carried out after the hot-rolling and before the final cold-rolling, after which the known, decarburization annealing and finishing annealing are carried out. The steel composition is adjusted to induce the secondary recrystallization by the AlN inhibitor. The reduction at the final cold-rolling is determined to be high to obtain a high magnetic flux density but tends to instabilize the secondary recrystallization unless the inventive decarburization is carried out.

Process for producing a grain-oriented electrical steel sheet having a

Extremely low watt-loss of W.sub.17/50 .ltoreq.0.88 w/kg is provided by the combination of extremely low carbon, silicon and nitrogen contents; a thin sheet thickness of 0.15 to 0.23 mm; a high magnetic flux density B.sub.10 .gtoreq.1.89 T; and copresence of coarse and fine (2 mm or less) grains, the distance (ND) between the fine grains controlled to 2.0 to 8.0 mm.

Grain-oriented silicon steel sheet and process for producing the same

A grain oriented magnetic steel sheet having excellent magnetic properties containing not more than 4.5% silicon, in which a &lt;001&gt; axis of individual grains coincides with a rolling direction of the steel sheet, a crystal plane parallel to the steel sheet surface is composed of a {h, k, o} plane which is rotated and dispersed about an axis in the rolling direction, and a tension ranging substantially from 350 to 1500 g/mm.sup.2 is given to the steel sheet in the rolling direction.

Method for producing a grain-oriented magnetic steel sheet having good

An electrical silicon steel sheet composed of secondary or tertiary recrystallized grains oriented in one or two directions, is produced by a process comprising a decarburization annealing operation in an oxidation atmosphere in which a ratio of PH.sub.2 O/PH.sub.2 wherein PH.sub.2 O represents a partial pressure of water vapor in said oxidation atmosphere and PH.sub.2 represents a partial pressure of hydrogen in said oxidation atmosphere, is adjusted to a value of 0.15 or more in an initial stage of said decarburization annealing operation and, then, to a value smaller than that in said initial stage in a final stage of said decarburization annealing operation.

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Kitakyushu, Japan

Kenzo Iwayama