Patent US3993445A successfully refreshed from Google Patents.
US3993445A
Expired / Lapsed
US
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Sintered ferritic stainless steel
Assignee: KEYSTONE CARBON COMPANY A PA CORP
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Filing: 1974-11-27
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Granted: 1976-11-23
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Expires: 1994-11-27
Abstract
Abstract A sintered ferritic stainless steel having an overall density no greater than 80% of full density. The steel consists essentially of, by weight, 12 to 30% chromium, up to 8% molybdenum, up to 2% silicon, up to 1.5% manganese, up to 0.04% phosphorus, up to 0.04% sulfur, up to 0.15% carbon, balance iron.
Inventors
- 👤 Orville W. Reen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 21:42
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/18; C22C38/22; C22C33/00; C22C33/02; C22C33/0257; C22C33/0278; C22C33/0285
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
64 words
A fully sintered ferritic stainless steel powder compact being corrosion resistant in chloride ion environments consisting essentially of, by weight, 12 to 30% chromium, up to 8% molybdenum, up to 2% silicon, up to 1.5% manganese, up to 0.04% phosphorus, up to 0.04% sulfur, up to 0.15% carbon, balance iron; said steel compact having an overall density no greater than 80% of full density.
Claim 2
Dependent Claim
64 words
A fully sintered ferritic stainless steel powder compact being corrosion resistant in chloride ion environments consisting essentially of, by weight, 12 to 30% chromium, up to 8% molybdenum, up to 2% silicon, up to 1.5% manganese, up to 0.04% phosphorus, up to 0.04% sulfur, up to 0.15% carbon, balance iron; said steel compact having an overall density no greater than 80% of full density.
Claim 3
Dependent Claim
21 words
A sintered ferritic stainless steel according to claim 1, having from 16 to 26% chromium and from 2 to 6% molybdenum.
Claim 4
Dependent Claim
21 words
A sintered ferritic stainless steel according to claim 1, having an overall density of from 45 to 80% of full density.
Claim 5
Dependent Claim
21 words
A sintered ferritic stainless steel according to claim 3, having an overall density of from 68 to 80% of full density.
Claim 6
Dependent Claim
41 words
A sintered ferritic stainless steel according to claim 1, having from 16 to 26% chromium, from 2 to 6% molybdenum, up to 1.5% silicon, up to 0.5% manganese, up to 0.03% phosphorus, up to 0.03% sulfur, and up to 0.04% carbon.
Claim 7
Dependent Claim
21 words
A sintered ferritic stainless steel according to claim 5, having an overall density of from 45 to 80% of full density.
Claim 8
Dependent Claim
21 words
A sintered ferritic stainless steel according to claim 6, having an overall density of from 68 to 80% of full density.
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) | 1979-11-23 | 1980-05-24 | 1980-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-11-23 | 1984-05-24 | 1984-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-11-23 | 1988-05-24 | 1988-11-23 | $7700.00 | Window Closed / Lapsed |