Patent US5225156A successfully refreshed from Google Patents.
US5225156A
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US
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Clean steel composition
Assignee: Metal Research Corp
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Filing: 1990-07-19
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Granted: 1993-07-06
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Expires: 2010-07-19
Abstract
Abstract Disclosed is a clean steel containing less than 30 ppm of oxygen, less than 30 ppm of sulfur, less than 150 ppm of nitrogen, 5 to 0.1 ppm of Mg and 25 to 0.1 ppm of Ca.
Inventors
- 👤 Tohei Ototani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:24
CPC Classifications
C; C21; C21C; C21C7/00; C21C7/0006; C21C7/0056; C22; C22B; C22B9/00; C22B9/04
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
56 words
A clean steel consisting essentially of by weight 0.0001%-0.5% of aluminum, 0.0001%-0.5% of silicon, 0.00001%-0.0005% of magnesium, 0.00001-0.0025% of calcium, 0.00001%-0.003% of oxygen, 0.0001%-0.003% of sulfur, and 0.0001%-0.015% of nitrogen, less than 2% of carbon, 0.0001%-0.5% of at least one element selected from the group consisting of titanium, niobium, tantalum and boron and the remainder iron.
Claim 2
Dependent Claim
56 words
A clean steel consisting essentially of by weight 0.0001%-0.5% of aluminum, 0.0001%-0.5% of silicon, 0.00001%-0.0005% of magnesium, 0.00001-0.0025% of calcium, 0.00001%-0.003% of oxygen, 0.0001%-0.003% of sulfur, and 0.0001%-0.015% of nitrogen, less than 2% of carbon, 0.0001%-0.5% of at least one element selected from the group consisting of titanium, niobium, tantalum and boron and the remainder iron.
Claim 3
Dependent Claim
90 words
A clean steel consisting essentially of by weight 0.0005%-0.5% of aluminum, 0.0001%-0.5% of silicon, 0.00001%-0.0005% of magnesium, 0.00001%-0.0025% of calcium, 0.00001%-0.003% of oxygen, 0.00001%-0.003% of sulfur and 0.0001%-0.015% of nitrogen less than 2% carbon and the remainder iron, wherein the clean steel further include 0.0001%-0.5% of at least one element selected from the group consisting of titanium, niobium, tantalum and boron, wherein said alloy steel further consists of at least one element selected from the group consisting of nickel, chromium, cobalt, tungsten, vanadium and molybdenum as a special alloy steel.
Claim 4
Dependent Claim
90 words
A clean steel consisting essentially of by weight 0.0005%-0.5% of aluminum, 0.0001%-0.5% of silicon, 0.00001%-0.0005% of magnesium, 0.00001%-0.0025% of calcium, 0.00001%-0.003% of oxygen, 0.00001%-0.003% of sulfur and 0.0001%-0.015% of nitrogen less than 2% carbon and the remainder iron, wherein the clean steel further include 0.0001%-0.5% of at least one element selected from the group consisting of titanium, niobium, tantalum and boron, wherein said alloy steel further consists of at least one element selected from the group consisting of nickel, chromium, cobalt, tungsten, vanadium and molybdenum as a special alloy steel.
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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) | 1996-07-05 | 1997-01-04 | 1997-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-07-05 | 2001-01-04 | 2001-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-07-05 | 2005-01-04 | 2005-07-06 | $7700.00 | Window Closed / Lapsed |