US4255187A
Expired / Lapsed
US
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Bismuth-containing steel
Assignee: Inland Steel Co
•
Filing: 1979-08-29
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Granted: 1981-03-10
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Expires: 1999-08-29
Abstract
Abstract A free machining cast steel shape containing bismuth which functions as a liquid metal embrittler. The ability of the bismuth to function as a liquid metal embrittler is enhanced by restricting the total amount of ingredients which lower the wetting ability of the bismuth to less than the bismuth content and by controlling the amount of strengthening elements added to the steel.
Inventors
- 👤 Debanshu Bhattacharya
- 👤 Dennis T. Quinto
- 👤 Michael O. Holowaty
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:28
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/60
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
58 words
In a free machining cast steel shape consisting essentially of, in wt.%, ______________________________________
carbon 0.06 to 1.0
manganese 0.3-1.6
silicon 0.30 max.
sulfur 0.03-0.50
phosphorous 0.12 max.
bismuth 0.05-0.40
iron essentially the balance,
______________________________________ the improvement wherein: the total amount of ingredients which lower the wetting ability of bismuth is less than the bismuth content of said steel.
Claim 2
Dependent Claim
58 words
In a free machining cast steel shape consisting essentially of, in wt.%, ______________________________________
carbon 0.06 to 1.0
manganese 0.3-1.6
silicon 0.30 max.
sulfur 0.03-0.50
phosphorous 0.12 max.
bismuth 0.05-0.40
iron essentially the balance,
______________________________________ the improvement wherein: the total amount of ingredients which lower the wetting ability of bismuth is less than the bismuth content of said steel.
Claim 3
Dependent Claim
28 words
In a free machining cast steel shape as recited in claim 1 wherein: said ingredients which lower the wetting ability of bismuth are copper, tin, zinc and nickel.
Claim 4
Dependent Claim
28 words
In a free machining cast steel shape as recited in claim 1 wherein said steel further comprises up to 0.3 wt.% lead and up to 0.06 wt.% tellurium.
Claim 5
Dependent Claim
29 words
In a free machining cast steel shape as recited in claim 1 wherein said steel includes at least 0.015 wt.% tellurium to enhance the wetting ability of said bismuth.
Claim 6
Dependent Claim
24 words
In a free machining cast steel shape as recited in claim 1 wherein the manganese content is greater than three times the sulfur content.
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Cited
US3973950A
Cited
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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) | 1984-03-09 | 1984-09-08 | 1985-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-09 | 1988-09-08 | 1989-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-09 | 1992-09-08 | 1993-03-10 | $7700.00 | Window Closed / Lapsed |