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US3902898A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Free-machining austenitic stainless steel
Assignee: Armco Inc
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Filing: 1973-11-08
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Granted: 1975-09-02
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Expires: 1993-11-08
Abstract
Abstract A free-machining austenitic stainless steel and machined products thereof comprising, by weight percent, 0.035% maximum carbon, 17 to 19% chromium, 8 to 10% nickel, 0.5% maximum manganese, 0.25 to 0.65% sulfur, up to 1% silicon, up to 0.20% phosphorus, up to 0.6% molybenum, and balance substantially iron. In the passivated condition the steel is resistant to corrosion, by reason of the critically low manganese content, in environments containing dilute citric, acetic, phosphoric and/or carbonic acids. The combination of machinability and corrosion resistance provides utility for machined fittings used in the beverage and food industry.
Inventors
- 👤 Jr Elbert E Denhard
- 👤 Jr William C Clarke
- 👤 Jr Robert M Larrimore
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 07:43
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/60
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
27 words
The steel claimed in claim 1, containing a maximum of about 0.03% carbon, a maximum of about 0.4% manganese, and from about 0.4 to about 0.5% sulfur.
Claim 2
Dependent Claim
14 words
The steel claimed in claim 1, wherein the maximum carbon content is about 0.03%.
Claim 3
Dependent Claim
25 words
The steel claimed in claim 1, wherein the maximum manganese content is about 0.4%, and wherein the maximum manganese to sulfur weight ratio is 1:1.
Claim 4
Dependent Claim
26 words
The steel claimed in claim 1, wherein sulfur is from about 0.4 to about 0.5%, and wherein the maximum manganese to sulfur weight ratio is 1:1.
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) | 1978-09-01 | 1979-03-03 | 1979-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-01 | 1983-03-03 | 1983-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-01 | 1987-03-03 | 1987-09-02 | $7700.00 | Window Closed / Lapsed |