Nippon Kokan Kabushiki Kaisha

Nkk Corporation

Takaho Kawawa

Kentaro Mori

Hirotaka Nakagawa

Akichika Ozeki

Hideaki Mizukami

Hideki Sato

Hirokazu Nomura

Yuji Sugitani

Hideyuki Yoshikoshi

Keisuke Nakahara

Masaru Okado

Tadashi Fujioka

Shinobu Miyahara

Tohru Arimura

Toshio Hinami

Masaharu Ito

A method for producing titanium fluoride comprises: a dissolution process, wherein iron-containing titanium material is dissolved in solutions containing hydrofluoric acid, fluoride solutions being produced; a first crystallization and separation process, wherein ferric fluoride is crystallized and ferric fluoride crystals thus obtained are separated from the fluoride solutions by cooling the fluoride solutions, crude titanium fluoride solutions being produced; a second crystallization and separation process, wherein a mixed salt of (NH.sub.4).sub.2 TiF.sub.6 and (NH).sub.3 FeF.sub.6 is crystallized and separated by mixing ammonium fluoride solutions with the crude titanium fluoride solutions to obtain a mixture and concentrating the mixture; a first pyrolysis process, wherein the ammonium fluoride salt is pyrolyzed at a temperature of from 300.degree. to 800.degree. C. in a stream of dry gas after having dried the ammonium fluoride, solid ferric fluoride (FeF.sub.3) and gaseous TF.sub.4, HF and NH.sub.3 being produced; a condensation and separation process, wherein the gaseous TiF.sub.4, HF and NH.sub.3 are condensed at a temperature of from 20.degree. to 280.degree. C. and followed by the TiF.sub.4 separation of solid.

Method for producing titanium fluoride

Powder manufacturing apparatus and method therefor

A method for manufacturing alloy comprising: allowing a consumable electrode consisting a single metal element to form a pair of electrodes which have the same element, to set plurality of the pair so that an electrode metal element of each of the plurality of the pair may be different from one another; generating arc between the electrodes in a non-oxidizing atmosphere, to allow the consumable electrodes to be melted at their top ends; and allowing molten drops produced by the melting to go down into a mold to form molten metal, and the molten metal to be cast into alloy consisting of two metal elements. Two pairs consisting of the consumable electrodes allow the two consumable electrodes to be set on an axis, with a predetermined distance between their top ends, on horizontal plane above the mold. The two pairs of the consumable electrodes are alternated by three pairs of the consumable electrodes when alloy consisting of three metal elements.

Method for manufacturing alloy

A mold for horizontally and continuously casting molten metal into a cast metal strand, which is horizontally connected, through a front nozzle, a feed nozzle and a break ring to an opening in a lower portion of a side wall of a tundish for a horizontal type continuous casting machine. Molten metal received in the tundish is intermittently and continuously withdrawn into a cast metal strand in the horizontal direction through the mold in a plurality of cycles each comprising one pull and one push. The transverse sectional area of the inner bore of the mold at the inlet end portion thereof becomes gradually larger from the inlet end of the mold toward the middle portion thereof over a prescribed distance (l), and the inner bore of the mold has substantially the same transverse sectional area for the remaining portion other than the inlet portion of the mold over the above-mentioned prescribed distance (l).

Mold for horizontally and continuously casting molten metal into cast

In continuously casting molten steel at least a pair of rolls is disposed near the leading end of the crater at which solidification of the molten steel in the cast piece completes so as to roll the cast piece at a reduction rate of from 0.1 to 2.0%. The variation in the thickness of the cast piece is detected and compared with a definite reference value for controlling the drawing speed and or the quantity of the secondary cooling water.

Method of continuously casting steel

A big-end-down ingot mold has a heat insulating chamber which, when the ratio of the width of the wider walls to that of the narrower walls of the mold is less than 1.7:1, is formed in each of the four side walls and, when the ratio is 1.7:1 or more, is formed in each of the two opposed wider walls and whose horizontal sectional areas each gradually increase from below toward above. By means of the heat insulating chambers the solidification rate of the molten metal is regulated to prevent the formation of secondary pipes and segregation around the pipes within an ingot cast in the mold.

Big-end-down ingot mold for casting metal

In the withdrawing stage following the secondary cooling zone, each pair of rolls of a plurality of pairs of rolls reduces the cross section less than 1.5 percent at the portion between the liquidus line and solidus one in unsolidified phase, thereby to produce a sound cast piece without producing the known center segregation and the known center porosity.

Continuous casting process

Growing community of inventors

Tokyo, Japan

Takaho Kawawa