US3904378A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Steel clad stainless composite article
Assignee: Armco Inc
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Filing: 1973-11-08
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Granted: 1975-09-09
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Expires: 1993-11-08
Abstract
Abstract This disclosure relates to a metallic composite article, i.e. ingot, slab, strip or sheet, having a thin stainless steel core sandwiched between two relatively thick low carbon or low alloy steel outer layers. The composite article is formed at the ingot stage by casting low carbon steel or low alloy steel simultaneously about a stainless steel plate suspended in a mold, which plate has had its major surfaces covered by a metallic protective layer so as to control the alloy depletion therefrom, especially the chromium to a value not less than about 11%, by weight. The resulting article exhibits excellent resistance to pitting and penetration in those corrosive environments where such phenomena are known to be a problem.
Inventors
- 👤 David A Higbee
- 👤 Joseph C Jasper
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:10
CPC Classifications
B; B22; B22D; B22D7/00; B22D7/02; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/923; Y10S428/924; Y10S428/925; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12771; Y10T428/12861; Y10T428/12951; Y10T428/12972; Y10T428/12979
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
74 words
A FLAT METALLIC COMPOSITE CAST INGOT COMPRISING A THIN STANLESS STEEL CORE WHOSE THICKNESS IS AT LEAST 0.5% OF SAID ARTICLE FUSION BONDED BETWEEN TWO THICKER OUTER LAYERS OF STEEL SELECTED FROM THE GROUP CONSISTING OF LOW ALLOY STEEL AND LOW CARBON STEEL, THE SAID STAINLESS STEEL CORE EXHIBITING SUBSTANTIALLY ITS ORIGINAL INTEGRITY, BY VIRTUE OF MINIMUM DIFFUSION OF CARBON INTO THE STANILESS STEEL, AND MINIMUM DIFFUSION OF CHROMIUM OUT OF THE STAINLESS STEEL.
Claim 2
Dependent Claim
74 words
A FLAT METALLIC COMPOSITE CAST INGOT COMPRISING A THIN STANLESS STEEL CORE WHOSE THICKNESS IS AT LEAST 0.5% OF SAID ARTICLE FUSION BONDED BETWEEN TWO THICKER OUTER LAYERS OF STEEL SELECTED FROM THE GROUP CONSISTING OF LOW ALLOY STEEL AND LOW CARBON STEEL, THE SAID STAINLESS STEEL CORE EXHIBITING SUBSTANTIALLY ITS ORIGINAL INTEGRITY, BY VIRTUE OF MINIMUM DIFFUSION OF CARBON INTO THE STANILESS STEEL, AND MINIMUM DIFFUSION OF CHROMIUM OUT OF THE STAINLESS STEEL.
Claim 3
Dependent Claim
26 words
A composite article in sheet or strip form, produced from an ingot according to claim 1, wherein said stainless steel core is at least 0.001 inches.
Claim 4
Dependent Claim
24 words
The composite article according to claim 2, wherein the ratio of said article thickness to said core thickness is between about 3:1 to 50:1.
Claim 5
Dependent Claim
22 words
The composite article according to claim 3, wherein the ratio of the article thickness to the core thickness is at least 10:1.
Claim 6
Dependent Claim
16 words
The composite article according to claim 2, wherein the core thickness is at least 0.005 inches.
Claim 7
Dependent Claim
29 words
The metallic composite article according to claim 1, wherein each of said outer layers is characterized by a variation in metallurgical characteristics from the outside to the stainless core.
Claim 8
Dependent Claim
32 words
The metallic composite article according to claim 6, wherein each of said layers is characterized by a variation in chemistry, crystalline structure and grain size from the outside to the stainless core.
Claim 9
Dependent Claim
74 words
A flat metallic composite cast ingot comprising a thin austenitic stainless steel core whose thickness is at least 0.5% of said article fusion bonded between two thicker outer layers of steel selected from the group consisting of low alloy steel and low carbon steel, said stainless steel core exhibiting substantially its original integrity, by virtue of minimum diffusion of carbon into the stainless steel, and minimum diffusion of chromium out of the stainless steel.
Claim 10
Dependent Claim
74 words
A flat metallic composite cast ingot comprising a thin austenitic stainless steel core whose thickness is at least 0.5% of said article fusion bonded between two thicker outer layers of steel selected from the group consisting of low alloy steel and low carbon steel, said stainless steel core exhibiting substantially its original integrity, by virtue of minimum diffusion of carbon into the stainless steel, and minimum diffusion of chromium out of the stainless steel.
Claim 11
Dependent Claim
26 words
A composite article in sheet or strip form, produced from an ingot according to claim 8, wherein said stainless steel core is at least 0.001 inches.
Claim 12
Dependent Claim
24 words
The composite article according to claim 9, wherein the ratio of said article thickness to said core thickness is between about 3:1 to 50:1.
Claim 13
Dependent Claim
22 words
The composite article according to claim 10, wherein the ratio of the article thickness to the core thickness is at least 10:1.
Claim 14
Dependent Claim
16 words
The composite article according to claim 9, wherein the core thickness is at least .005 inches.
Claim 15
Dependent Claim
30 words
The metallic composite article according to claim 8, wherein each of said outer layers is characterized by a variation in metallurgical characteristics from the outside to the stainless steel core.
Claim 16
Dependent Claim
33 words
The metallic composite article according to claim 13, wherein each of said layers is characterized by a variation in chemistry, crystalline structure and grain size from the outside to the stainless steel core.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-08 | 1979-03-10 | 1979-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-08 | 1983-03-10 | 1983-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-08 | 1987-03-10 | 1987-09-09 | $7700.00 | Window Closed / Lapsed |