Nippon Steel Corporation

Kinichi Kimura

Mitsuo Ishii

Hirofumi Yoshimura

Masayuki Hayashi

Kazuhiro Takahashi

Michio Kaneko

Kiyonori Tokuno

Teruhiko Hayashi

Junichi Tamenari

Hiroshi Shimizu

Tatsuo Yamazaki

Yutaka Sadano

Shoichi Maruyama

Akihiko Kusano

Haruo Ohguro

Jin-ichi Takamura

Isamu Takayama

Satoshi Yamamoto

Jinichi Takamura

Jin Takamura

Noboru Takeuchi

Titanium material less susceptible to discoloration and method for thereof are provided. Titanium materials less susceptible to discoloration in the atmosphere are obtainable by controlling the fluorine and carbon contents in the oxide film on the surface thereof and the thickness of the oxide film. Such titanium materials are obtainable by dissolving the surface thereof in an aqueous fluonitric acid solution with a nitric acid concentration of not higher than 80 g/l or heat-treating at between 300 and 900&#xb0; C. in a vacuum or in an inert gas atmosphere of argon or helium after dissolving in the aqueous fluonitric acid solution.

Titanium material less susceptible to discoloration and method for production thereof

Titanium resistant to discoloration in an atmospheric environment characterized by having an average carbon concentration of 14 at % or less in a range to a depth of 100 nm from the surface and having an oxide film of a thickness of 12 to 40 nm at its surface. Titanium resistant to discoloration in an atmospheric environment characterized in that, in X-ray diffraction of its surface, a ratio (X/X) of a (200) peak intensity Xof TiC to a (110) peak intensity Xof titanium is not more than 0.18 and by having an oxide film of a thickness of 12 to 40 nm at its surface.

Titanium resistant to discoloration in atmospheric environment and process of production of same

Method of straightening wire rods of titanium and titanium alloy

This present invention is characterized in that a titanium material on an .alpha. or (.alpha.+.beta.) titanium alloy material hydrogenated in an amount of 0.02 to 2% by weight of hydrogen is heated to a temperature above the .beta. transformation point and below 1100.degree. C., is hot worked in that temperature range at a reduction of 30% or more, the hot working is terminated in a .beta. single phase temperature region, and cooling to 400.degree. C. or less, and annealing in vacuum are then carried out, whereby titanium and titanium alloy materials having a fine acicular microstructure are obtained.

Process for preparing titanium and titanium alloy having fine acicular

According to the present invention, titanium and titanium alloy materials having a fine equiaxed microstructure are produced. A titanium, .alpha. titanium alloy or (.alpha.+.beta.) titanium alloy material is hydrogenated in an amount of 0.02 to 2% by weight. If necessary, the hydrogenated material is subjected to pretreatment [i.e., heated above 700.degree. C. (.beta. transformation point)] and/or working (i.e., working at 450.degree. to 950.degree. C., or temperatures above .beta. transformation point and below 1100.degree. C.). The material is then aged at 10.degree. to 530.degree. C. or 10.degree. to 700.degree. C. (in the case of working at temperatures above .beta. transformation point), and finally dehydrogenated and recrystallized to prepared a material having a fine equiaxed microstructure.

Process for preparing titanium and titanium alloy materials having a

In the production of titanium and (.alpha.+.beta.)-type titanium alloy materials, a material hydrogenated in an amount of 0.02 to 2% by weight of hydrogen is worked at a temperature of 450.degree. to 900.degree. C. at a reduction of more than 60%, and the material is dehydrogenated and annealed in vacuum. The working of the titanium material is carried out at 450.degree. to 800.degree. C., and the working of the (.alpha.+.beta.)-type titanium alloy material is carried out at 550.degree. to 900.degree. C. Furthermore, in the production of titanium, .alpha.-type titanium alloy, and (.alpha.+.beta.)-type titanium alloy materials, a material hydrogenated in an amount of 0.02 to 2% by weight of hydrogen is subjected to a heat treatment wherein the material is heated at a temperature not lower than the .beta. transformation temperature and then cooled, the material is worked at a temperature of 450.degree. to 950.degree. C. at a reduction not lower than 20%, the material is dehydrogenated and annealed in the vacuum, the working of the titanium material is carried out at 450.degree. to 800.degree. C., the working of the .alpha.-type titanium alloy material is carried out at 600.degree. to 950.degree. C., and the working of the (.alpha.+.beta.)-type titanium alloy material is carried out at 550.degree. to 900.degree. C.

Process for production of titanium and titanium alloy material having

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Hikari, Japan

Kinichi Kimura