US3615917A
Expired / Lapsed
US
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Process for diffusing silicon into sheet steel
Assignee: Bethlehem Steel Corp
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Filing: 1969-07-11
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Granted: 1971-10-26
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Expires: 1989-07-11
Abstract
Abstract A process for solid-state diffusion of silicon into sheet steel containing not more than 0.05 percent carbon, the process including preparing sheet steel by conventional methods of melting, pouring and rolling, coating the surfaces of the sheet steel with a layer of powder containing about 15 percent to about 95 percent silicon and the remainder substantially calcium, iron and incidental impurities, compacting the powder onto the sheet and heat treating the composite thus formed in a protective environment to cause a solid-state diffusion of the diffusible silicon into the sheet steel.
Inventors
- 👤 Paik W Shin
- 👤 Richard M Willison
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 06:50
CPC Classifications
C; C23; C23C; C23C10/00; C23C10/28; C23C10/34; C23C10/36; C23C10/44; C23C10/46; C23C10/30
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
21 words
Process as defined in claim 1 in which the sheet steel of step (a) contains not more than 0.01 percent carbon.
Claim 2
Dependent Claim
40 words
Process as defined in claim 1 in which the diffusion treatment of step (c) is carried out for a time and at a temperature sufficient to cause diffusion of the silicon substantially uniformly throughout the entire thickness of the sheet.
Claim 3
Dependent Claim
40 words
Process as defined in claim 2 in which the diffusion treatment of step (c) is carried out for a time and at a temperature sufficient to cause diffusion of the silicon substantially uniformly throuGhout the entire thickness of the sheet.
Claim 4
Dependent Claim
26 words
Process as defined in claim 1 including the further steps of (d) cold rolling the product of step (c), and (e) annealing the cold rolled product.
Claim 5
Dependent Claim
26 words
Process as defined in claim 2 including the further steps of (d) cold rolling the product of step (c), and (e) annealing the cold rolled product.
Claim 6
Dependent Claim
34 words
Process as defined in claim 1 in which the diffusion treatment of step (c) is carried out at a temperature of at least 1,600* F. or a time sufficient to obtain the desired diffusion.
Claim 7
Dependent Claim
34 words
Process as defined in claim 2 in which the diffusion treatment of step (c) is carried out at a temperature of at least 1,600* F. for a time sufficient to obtain the desired diffusion.
Claim 8
Dependent Claim
19 words
Process as defined in claim 1 in which the protective environment of step (c) is a dry hydrogen atmosphere.
Claim 9
Dependent Claim
19 words
Process as defined in claim 2 in which the protective environment of step (c) is a dry hydrogen atmosphere.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-10-25 | 1975-04-26 | 1975-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-25 | 1979-04-26 | 1979-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-25 | 1983-04-26 | 1983-10-26 | $7700.00 | Window Closed / Lapsed |