US3779817A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing quenched and tempered hollow steel structural members of polygonal cross section
Assignee: United States Steel Corp
•
Filing: 1972-09-25
•
Granted: 1973-12-18
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Expires: 1992-09-25
Abstract
Abstract Method of producing quenched and tempered hollow steel structural members of polygonal cross section includes the steps of hot rolling a hollow steel tube, austenitizing the tube, water quenching it, reheating the tube to a tempering temperature just below the lower critical transformation temperature, and rolling the tube to the desired polygonal cross section while holding the temperature of the member at the tempering temperature.
Inventors
- 👤 W Brunko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:07
CPC Classifications
C; C21; C21D; C21D8/00; C21D8/10
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
13 words
A method according to claim 1 wherein said austenitizing temperature is above 1550*F.
Claim 2
Dependent Claim
17 words
A method according to claim 2 wherein said austenitizing temperature is from about 1600*F to about 1750*F.
Claim 3
Dependent Claim
18 words
A method according to claim 1 wherein said tube is water quenched to a temperature below about 200*F.
Claim 4
Dependent Claim
18 words
A method according to claim 4 wherein said tube is water quenched to a temperature of about 150*F.
Claim 5
Dependent Claim
17 words
A method according to claim 1 wherein said tempering temperature is from about 1150*F to about 1225*F.
Claim 6
Dependent Claim
14 words
A method according to claim 1 wherein said polygonal cross-section is a round-cornered rectangle.
Claim 7
Dependent Claim
14 words
A method according to claim 1 wherein said polygonal cross-section is a round-cornered square.
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) | 1976-12-17 | 1977-06-18 | 1977-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-17 | 1981-06-18 | 1981-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-17 | 1985-06-18 | 1985-12-18 | $7700.00 | Window Closed / Lapsed |