Nippon Steel Corporation

Japan Atomic Energy Research Institute

Hirofumi Yoshimura

Mitsuo Ishii

Kinichi Kimura

Tadashi Sawatani

Masayuki Hayashi

Naoomi Yamada

Masanori Ueda

Hidehiko Sumitomo

Masayuki Yamamoto

Jirou Harase

Hiroshi Yada

Shigeru Ohkita

Shigeru Minamino

Jin-ichi Takamura

Hiroyuki Honma

Hideo Nakajima

Katsuo Kaku

Takeshi Nishi

Jinichi Takamura

Takao Horiya

Rokuro Fujimoto

Jin Takamura

Toshinari Andou

Toshiaki Nishida

Titanium for conductor conduit in superconducting coil

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

The ferritic stainless steel sheet involves a problem that the ridging is likely to generate at the forming step, such as the deep drawing step. The ridging is believed to be caused by a band structure in the hot rolled band, which structure exerting an influence on the formability of a cold rolled sheet. The ridging is prevented in the present invention by means of the combination of the three technical measures: incorporating aluminum into a ferritic stainless steel; heating a slab to a low temperature of 1200.degree. C. or less; and, carrying out a drastic hot rolling of at least one pass with the draft of 20%/pass or more. As a result of these technical measures, the structure of a hot rolled band is made and uniform and thus both the formability and anti-ridging property are enhanced.

Method for producing ferritic stainless steel sheets or strips

A ferritic stainless steel having excellent formability, for example, in a deep drawing procedure, contains 0.04 to 0.1 weight % of C, 1.0 weight % or less of Si, 0.75 weight % or less of Mn, 10 to 30 weight % of Cr, 0.5 weight % or less of Ni, 0.025 weight % or les of N, 2 to 30 ppm of boron, and optionally, 0.005 to 0.4 weight % of an additional alloy component consisting of Al and, further optionally, a further additional alloy component consisting of at least one member selected from 0.005 to 0.6 weight % of Ti, 0.005 to 0.4 weight % of Nb, V, and Zr, 0.02 to 0.50 weight % of Cu, and 0.05 weight % or less of Ca and Ce, the sum of the contents of C and N being 0.0502 weight % or more.

Ferritic stainless steel having excellent formability

An austenitic stainless steel of a specific composition is cast into a slab and subjected to hot rolling, descaling, cold rolling without a step of preliminary annealing, and annealing. The steel sheet or strip thus obtained is of excellent quality with a satisfactorily low degree of anisotropy.

Process for producing an austenitic stainless steel sheet or strip

In a process for the production of cold rolled ferritic stainless steel sheets or strips, a hot rolled strips has been annealed by a long time batchwise annealing and cold rolling and recrystallization annealing have been repeated usually twice. In the present invention, a hot rolled steel strip of an Al-containing ferritic stainless steel is heated by continuous annealing to a temperature of from 850.degree. to 1100.degree. C., AlN (aluminum nitride) is precipitated in the dispersed state and then cooling the strip to a temperature of 700.degree. to 900.degree. C., performing subsequent cooling to a level not higher than 200.degree. C. at such a cooling rate that a chromium depletion layer, which causes a gold dust defect, is not formed around the chromium carbonitride. Single cold rolling and recrystallization annealing are carried out in combination until the thickness is reduced to the gauge thickness.

Process for the production of ferritic stainless steel sheets or strips

A welding material for low temperature steels composed of a core wire or coated core wire, the wire containing 0.05 to 0.5% carbon, 0.15 to 0.75% silicon, 20 to 50% manganese, 4 to 17% chromium, 0.005 to 0.5% nitrogen and more than 0.5 to 10% molybdenum, with the balance being iron and unavoidable impurities.

Welding material for low temperature steels

A low temperature high strength tough steel is provided by effecting a series of heat treatments at predetermined temperatures. The steel comprises C, Si, Mn, Ni, Mo, Nb, N, Al, and if necessary, V, Ti, Cr, Ca or Ce in predetermined amounts with the rest iron and unavoidable impurities.

Method for producing a low temperature high strength tough steel

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Hikari, Japan

Hirofumi Yoshimura