Nkk Corporation

Other

Kuninori Minakawa

Hiroyoshi Suenaga

Hideaki Fukai

Atsushi Ogawa

Kazuhide Takahashi

Seishi Tsuyama

Hiroyoshi Takeuchi

Toshio Sakiyama

Takeshi Ito

Shinji Mitao

Masahiko Naoe

Tetsuo Sakiyama

Masakuni Takagi

Shinichiro Otaka

Misao Ishikawa

Shin-ichi Takagi

A method for making an .alpha.+.beta. titanium alloy comprising: preparing an .alpha.+.beta. titanium alloy, hot-working the titanium alloy in an .alpha.+.beta. phase region, heating and then heat treating the hot-worked titanium alloy to a temperature from the .beta.-transus minus 55.degree. C. to the .beta.-transus minus 10.degree. C., air cooling the heat treated titanium alloy, heating and then heat treating the air cooled titanium alloy to a temperature from the .beta.-transus minus 250.degree. C. to the .beta.-transus minus 120.degree. C., and air cooling the heat treated titanium alloy.

Method for making .alpha.+.beta. titanium alloy

A method of making a titanium base alloy comprising the steps of heating a titanium base alloy to a temperature ranging from .beta.-transus minus 250.degree. C. to .beta.-transus; and hot working the heated alloy with a reduction ratio of at least 50%. The titanium base alloy consists essentially of about 3.42 to 5 wt. % Al, 2.1 to 3.7 wt. % V, 0.85 to 2.37 wt. % Mo, at least 0.01 wt. % O, at least one element selected from the group consisting of Fe, Co, Cr, and the balance being titanium. The invention also includes superplastic forming of said alloys. The titanium alloy satisfies the following equations:

Method of making Ti-Al-V-Mo alloys

A method of making a titanium base alloy comprising the steps of: heating a titanium base alloy to a temperature ranging from .beta.-transus minus 250.degree. C. to 5-transus; the titanium base alloy consisting essentially of about 3.42 to 5 wt. % Al, 2.1 to 3.7 wt. % V, 0.85 to 3.15 wt. % Mo, at least 0.01 wt. % 0, at least one element selected from the group consisting of Fe, Ni, Co and Cr, and the balance being titanium, and satisfying the following equations: 0.85 wt. %.ltoreq.X wt %.ltoreq.3.15 wt %, 7 wt %.ltoreq.Y wt %.ltoreq.13 wt. %, X wt. %=Fe wt. %+Ni wt. %+Co wt. %+0.9.times.Cr wt. %, Y wt. %=2.times.Fe wt. %+2.times.Ni wt. %+2.times.Co wt. %+1.8.times.Cr wt. %+1.5.times.V wt. %+Mo wt. %, and hot working the heated alloy with a reduction ratio percent of at least 50%.

Ti-Al-V-Mo-O alloys with an iron group element

A magnetic disk substrate having a composition wherein (V/13)+(Fe/20)+(Cr/17)+(Ni/31)+(Co/23) are no greater than 0.010%, Rem+Si+B+W are no greater than 0.015% (where Rem denotes rare earth metals), 0+2N+0.75C are no less than 0.03% and no greater than 0.5%, and the remainder consists substantially of Ti, all % being weight %.

Magnetic disk substrate

A Titanium base alloy with improved superplastic, hot workability, cold workability, and mechanical properties is provided. The alloy has about 4% Al and 2.5% V, with below 0.15% O, with 2% Fe and 2% Mo, 0.85.about.3.15 wt. % Mo, and at least one element from the group of Fe, Ni, Co, and Cr as beta stabilizing elements, and as contributing elements to the lowering of beta transus, finally to the improvement of the superplastic properties, and hot and cold workability, with the grain size of below 5 .mu.m. A method of making thereof is provided with the reheating temperature between beta transus minus 250.degree. C. and beta transus. A method of superplastic forming thereof is provided with the heat treating temperature between beta transus minus 250.degree. C. and beta transus.

Titanium base alloy for excellent formability and method of making

A method of manufacturing a titanium alloy magnetic disk substrate comprising (a) cold-rolling an alloy plate at a rolling ratio of no less than 30%, the alloy plate comprising 0.5 wt. % to 1.0 wt. % of Mo and containing oxygen, nitrogen and carbon in amounts such that O+2N+0.75C is from 0.03 wt. % to 0.5 wt. % of the titanium alloy, and the balance being Ti, wherein O is the wt. % of oxygen, N is the wt. % of nitrogen and C is the wt. % of C to form a magnetic disk substrate material and then (b) thermal-flattening the magnetic substrate material from step (a) under a condition defined as follows:

Method of manufacturing a magnetic disk substrate

A method for lapping two surfaces of a titanium disk comprises inserting loosely a titanium disk to be lapped into an opening in a disk-type carrier, the carrier rotating and revolving between an upper surface plate and a lower surface plate which are held in parallel with each other and which applies lapping pressure to the titanium disk, feeding abrasives between the surface plates and the titanium disk and satisfying the following relationship between thickness t (mm) of the titanium disk and thickness T (mm) of the carrier:

Method for lapping two surfaces of a titanium disk

According to a mirror surface polishing process of the present invention, it is possible to produce Ti-made magnetic disc substrate which have the excellent flatness degree and surface roughness in that the average roughness is not more than 0.05 .mu.m and the flatness degree of the outer periphery is not more than 0.15 .mu.m.

Method for mirror polishing of ti-made magnetic disk substrate

After the surface roughness of a titanium substrate is set to be R.sub.max .ltoreq.0.08 .mu.m, a hardened layer having a hardness of H.sub.v .gtoreq.250 is formed thereon to have a thickness of 50 to 250 .mu.m by sputtering, thereby manufacturing a titanium magnetic disk substrate.

Method of manufacturing titanium magnetic disk substrate

A titanium base alloy with improved superplastic, hot workability, cold workability, and mechanical properties is provided. The alloy has about 4% Al and 2.5% V, with below 0.15% O, with 2% Fe and 2% Mo, 0.85.about.3.15 wt. % Mo, and at least one element from the group of Fe, Ni, Co, and Cr as beta stabilizing elements, and as contributing elements to the lowering of beta transus, finally to the improvement of the superplastic properties, and hot and cold workability, with the grain size of below 5 .mu.m. A method of making thereof is provided with the reheating temperature between beta transus minus 250.degree. C. and beta transus. A method of superplastic forming thereof is provided with the heat treating temperature between beta transus minus 250.degree. C. and beta transus.

Titanium base alloy for excellent formability

A magnetic disk substrate composition 0.5 wt % to 1.0 wt % of Mo, 0.03 wt % to 0.5 wt % of O+2N+0.75C, and a balance of Ti. The alloy sheet having a composition of above range is cold-rolled at a rolling ratio of 30% or more to form a magnetic disk substrate material, and the material is thermal-flattened under the following condition:

Magnetic disk substrate and method of manufacturing the same

A method for manufacturing titanium clad steel plate by forming a slab assembly having an alloy steel substrate, a titanium metal or alloy cladding on said substrate and a Ni-Cr alloy foil or film having opposed surfaces between said alloy steel and said cladding. The Ni-Cr alloy foil or film has one surface in surface contact with the cladding and the opposed surface in surface contact with the alloy steel substrate. The Ni-Cr alloy contains 32.5 to 40 wt. % Cr and 55 to 65 wt. % Ni. The slab assembly is heated at a temperature of 850.degree. to 1010.degree. C. The heated slab assembly is hot rolled with a reduction ratio of 30% or more to form the titanium clad steel plate.

Method for manufacture titanium clad steel plate

A heat treating method for a high strength aluminum alloy comprising the steps of: solution heat treating of an aluminum alloy consisting essentially of about 3 to 9 wt. % Zn, 1 to 6 wt. % Mg, 1 to 3 wt. % Cu, at least one element selected from the group consisting of 0.1 to 0.5 wt. % Cr, 0.1 to 0.5 wt. % Zr, 0.2 to 1.0 wt. % Mn, and the balance being Al, heating of the solution heat treated alloy to a temperature of a lower temperature zone of from 100.degree. to 140.degree. C. and optionally maintaining the alloy at a temperature within the lower temperature zone for a duration of time, reheating of the alloy to a temperature of an upper temperature zone of from 160.degree. to 200.degree. C. and optionally maintaining the alloy at a temperature within the upper temperature zone for a second duration of time, cooling of the alloy to a temperature of the lower temperature zone, and repeating the steps (2), (3), and (4) at least twice.

Heat treating method for high strength aluminum alloy

A heat-resistant TiAl alloy having excellent room-temperature fracture toughness, high-temperature oxidation resistance and high-temperature strength is disclosed. Said alloy consists essentially of from 29 to 35 wt. % aluminum, from 0.5 to 20 wt. % nobium, and at least one element selected from the group consisting of from 0.1 to 1.8 wt. % silicon, and from 0.3 to 5.5 wt. % zirconium, the balance being titanium and incidental impurities. Preferably impurities are limited to 0.6 wt.-% oxygen, 0.1 wt.-% nitrogen and 0.5 wt.-% hydrogen.

Heat-resistant TiAl alloy excellent in room-temperature fracture

The invention provides a titanium alloy having improved superplastic forming characteristics and mechanical characteristics. A titanium alloy having superplastic forming characteristics consisting essentially of about 5.5 to 6.75 wt. % Al, 3.5 to 4.5 wt. % V, 0.01 to 0.2 wt. % O, 0.85 to 3.15 wt. % Fe, 0.85 to 3.25 wt. % Mo, with 2.times.Fe wt. %+Mo wt. % being from 3 to 8, and balance titanium; said alloy containing .alpha.-crystals having a grain size below about 6 .mu.m in diameter. The Fe and Mo act as .beta.-stabilizing elements and contributing elements to lowering the beta transus and to the improvement of the superplastic characteristics.

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Tokyo, Japan

Kuninori Minakawa