US3928088A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ferritic stainless steel
Assignee: Carpenter Technology Corp
•
Filing: 1973-11-09
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Granted: 1975-12-23
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Expires: 1993-11-09
Abstract
Abstract Ferritic, preferably free-machining stainless steel containing 0.08% max. carbon, 0.06-0.20% nitrogen, 2.5% max. manganese, 0.50% max. sulfur (and/or selenium), 17.5-19.5% chromium, 1.52.5% molybdenum with the balance iron plus optional elements and incidental impurities, characterized by a unique combination of corrosion resistance and impact toughness, plus free machinability in its preferred form.
Inventors
- 👤 Donald K Schlosser
- 👤 Lewis P Myers
- 👤 Robert L Caton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:25
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/18; C22C38/22; C22C38/60
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
11 words
A FERRITIC STAINLESS STEEL CONSISTING ESSENTIALLY IN WEIGHT PERCENT OF ABOUT
Claim 2
Dependent Claim
11 words
A FERRITIC STAINLESS STEEL CONSISTING ESSENTIALLY IN WEIGHT PERCENT OF ABOUT
Claim 3
Dependent Claim
12 words
Ferritic stainless steel as set forth in claim 1 containing 0.25-0.4% sulfur.
Claim 4
Dependent Claim
22 words
Free-machining ferritic stainless steel as set forth in claim 2 containing about 0.06% maximum carbon, about 1.7-2.2% manganese and about 0.08-0.16% nitrogen.
Claim 5
Dependent Claim
14 words
Free-machining ferritic stainless steel as set forth in claim 3 containing about 18.0-19.0% chromium.
Claim 6
Dependent Claim
14 words
Free-machining ferritic stainless steel as set forth in claim 3 containing about 1.7-2.2% molybdenum.
Claim 7
Dependent Claim
14 words
Free-machining ferritic stainless steel as set forth in claim 4 containing about 1.7-2.2% molybdenum.
Claim 8
Dependent Claim
14 words
Free-machining ferritic stainless steel as set forth in claim 6 containing about 0.08-0.14% nitrogen.
Claim 9
Dependent Claim
21 words
Free-machining ferritic stainless steel as set forth in claim 7 containing about 5 to 20 percent highly tempered partially decomposed martensite.
Claim 10
Dependent Claim
41 words
Free-machining ferritic stainless steel as set forth in claim 3 containing about 1.8% manganese, about 0.4% silicon, 0.35% sulfur, about 18.4 to 18.6% chromium, about 2% molybdenum, about 0.085-0.14% nitrogen, and about 5 to 20 percent highly tempered partially decomposed martensite.
Claim 11
Dependent Claim
14 words
Free-machining ferritic stainless steel as set forth in claim 9 containing about 0.130-0.140% nitrogen.
Claim 12
Dependent Claim
48 words
A stainless steel article formed from a ferritic stainless steel having the composition set forth in claim 1 hot worked from about 1,800*-2,200*F, annealed at about 1,200*-1,600*F and quenched so as to contain about 5 percent to 50 percent highly tempered, partially decomposed martensite free of acicular structure.
Claim 13
Dependent Claim
51 words
The stainless steel article set forth in claim 11 foRmed from a ferritic stainless steel containing 0.25-0.4% sulfur, about 1.7-2.2% manganese, about 0.08-0.16% nitrogen, about 18.0-19.0% chromium, about 1.7-2.2% molybdenum, a maximum of about 0.06% carbon, and about 5 to 20 percent highly tempered, partially decomposed martensite free of acicular structure.
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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) | 1978-12-22 | 1979-06-23 | 1979-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-22 | 1983-06-23 | 1983-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-22 | 1987-06-23 | 1987-12-23 | $7700.00 | Window Closed / Lapsed |