US4431461A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for producing Al-base alloy substrates for magnetic recording media
Assignee: KOBE SEIKO SHO 3-18 WAKINOHAMA-CHO 1-CHOME CHUO-KU KOBE-SHI JAPAN KK
•
Filing: 1981-01-28
•
Granted: 1984-02-14
•
Expires: 2001-01-28
Abstract
Abstract A method for producing Al-base alloy substrates for magnetic discs, which comprises continuously casting into a strip of a thickness of 4 to 15 mm a molten alloy composition containing alloy components consisting of 2-6% of Mg, less than 1% of Mn, less than 0.3% of Fe, less than 0.25% of Zn and less than 0.35% of Cr and a grain refiner comprising less than 0.08% of Ti and/or less than 0.01% of B, followed by rolling.
Inventors
- 👤 Kohzoh Hoshino
- 👤 Muneo Mizuno
- 👤 Hiroshi Murakado
- 👤 Yoshinobu Kitao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:14
CPC Classifications
C; C22; C22C; C22C21/00; C22C21/06; B; B21; B21B; B21B3/00; B21B3/003; G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/739; G11B5/73911; G11B5/73917; G11B5/73919; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12465
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
187 words
A method for manufacturing magnetic memory discs, comprising: (a) continuously casting into a strip of a thickness of 4 to 15 mm a molten alloy composition containing alloy components consisting essentially of 2-6 wt% of Mg, less than 1 wt% of Mn, less than 0.3 wt% of Fe, less than 0.25 wt% of Zn and less than 0.35 wt% of Cr and at least one element selected from the group consisting of less than 0.08wt% of Ti and less than 0.01 wt% of B, the balance being aluminum and the inevitable impurities, the alloying components being present in sufficient numbers and amounts to give an alloy disc-substrate of sufficient strength by virtue of the intermetallic compounds which form in the alloy, and allowing said alloy to solidify at a rate rapid enough so that the size of the intermetallic compounds which precipitate does not exceed 3 microns; (b) rolling the resulting cast strip; (c) cutting the magnetic disc substrates from said strip, and; (d) coating the disc substrates with a magnetic layer to a reduced thickness made possible by the smooth surface characteristics of the underlying substrate.
Claim 2
Independent Claim
187 words
A method for manufacturing magnetic memory discs, comprising: (a) continuously casting into a strip of a thickness of 4 to 15 mm a molten alloy composition containing alloy components consisting essentially of 2-6 wt% of Mg, less than 1 wt% of Mn, less than 0.3 wt% of Fe, less than 0.25 wt% of Zn and less than 0.35 wt% of Cr and at least one element selected from the group consisting of less than 0.08wt% of Ti and less than 0.01 wt% of B, the balance being aluminum and the inevitable impurities, the alloying components being present in sufficient numbers and amounts to give an alloy disc-substrate of sufficient strength by virtue of the intermetallic compounds which form in the alloy, and allowing said alloy to solidify at a rate rapid enough so that the size of the intermetallic compounds which precipitate does not exceed 3 microns; (b) rolling the resulting cast strip; (c) cutting the magnetic disc substrates from said strip, and; (d) coating the disc substrates with a magnetic layer to a reduced thickness made possible by the smooth surface characteristics of the underlying substrate.
Claim 3
Dependent Claim
29 words
The method of claim 1, wherein said titanium is present in said alloy in an amount effective to produce a fine grain structure and fewer micro-segregations in said strip.
Claim 4
Dependent Claim
22 words
The method of claim 2, wherein said titanium is present in said alloy in an amount of at least 0.001% by weight.
Claim 5
Dependent Claim
29 words
The method of claim 1, wherein said boron is present in said alloy in an amount effective to produce a fine grain structure and fewer micro-segregations in the strip.
Claim 6
Dependent Claim
22 words
The method of claim 1, wherein said boron is present in said alloy in an amount of at least 0.0005% by weight.
Claim 7
Dependent Claim
17 words
The method of claim 1, wherein said rolling step includes cold rolling with a 50% reduction ratio.
Claim 8
Dependent Claim
11 words
A magnetic recording disc prepared by the method of claim 1.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-02-13 | 1987-08-15 | 1988-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-13 | 1991-08-15 | 1992-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-13 | 1995-08-15 | 1996-02-14 | $7700.00 | Window Closed / Lapsed |