Nippon Steel Corporation

Nippon Steel Chemical Co., Ltd.

Nippon Graphite Fiber Corporation

Masatoshi Furuyama

Yutaka Arai

Tadao Tomioka

Osamu Kato

Takeshi Hamada

Tsutomu Kihara

Michiharu Harakawa

Hirofumi Sunago

Ken Kobayashi

Yasunori Sajiki

Shigeo Hara

Hajime Nakajima

Yoshiyuki Doken

Yoshio Kishimoto

Tsutomu Nakamura

In a step of spinning a molten mesophase pitch in a process for manufacturing a pitch-type carbon fiber, the pitch is allowed to pass through an orifice and to be contracted once, is then expanded in an introduction port with a diameter greater than that of the orifice, and is then allowed to pass through an outlet pore formed at a collecting portion to spin the pitch. The pitch-type carbon fiber has a high elastic modulus in tension and high compressive strength.

Process for manufacturing pitch-type carbon fiber

A graphitized fiber heat-treated at a temperature higher than 2300.degree. C. in an inert atmosphere, of which oxidation weight reduction rate A in dry air at 650.degree. C. is in the range defined by the equation (1), of which BET specific surface area S determine by nitrogen or krypton adsorption technique at -196.degree. C. is in the range defined by the equation (2), and of which pore volume determined by the carbon dioxide adsorption technique at 25.degree. C. is 0.001 ml/g or less: ##EQU1## where, A is the oxidation weight reduction rate in dry air at 650.degree. C. in min.sup.-1

High strength carbon fiber and pre-carbonized fiber

A process for producing a carbon fiber by subjecting a pitch fiber, obtained by melt spinning a carbonaceous mesophase pitch, to stabilization, followed by a carbonization or graphitization treatment, wherein the stabilization is carried out under an oxidative atmosphere containing 0.1% to 40% by volume of NO.sub.2 and 4% to 40% by volume of H.sub.2 O at a temperature of from 100.degree. C. to 400.degree. C.

Process for producing mesophase pitch-based carbon fibers

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Kawasaki, Japan

Masatoshi Furuyama