US4740255A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High strength weldable seamless tube of low alloy steel
Assignee: Individual
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Filing: 1986-03-17
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Granted: 1988-04-26
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Expires: 2006-03-17
Abstract
Abstract A high strength electric furnace, vacuum degassed and weldable seamless tube of low alloy steel containing 0.22 to 0.28% carbon, 1.20 to 1.4% manganese, not more than 0.035% phosphorus, not more than 0.02 sulphur, 0.15 to 0.35% silicon, 0.20 to 0.30% chromium, not more than 0.05% nickel, 0.15 to 0.60% molybdenum, 0.02 to 0.04% titanium, 0.0007 to 0.0025% boron, 0.007 to 0.050% aluminum and the balance iron. Where the pipe has a wall thickness of 11/8 inch or less the percentage molybdenum is preferably 0.15 to 0.20% whereas if the wall thickness is 1.18 inches or greater the preferred molybdenum content is 0.40 to 0.60%. The pipe is preferably heated to an austenization temperature of about 1,550° F. followed by simultaneous internal and external quenching and tempering at a temperature of about 1140° F.
Inventors
- 👤 Robert B. Manton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:15
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/18; C22C38/32; C22C38/22; Y; Y10; Y10S; Y10S148/00; Y10S148/902; Y10S148/909; Y10T; Y10T428/00; Y10T428/12; Y10T428/12292
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
140 words
An electric furnace melted, vacuum degassed high strength weldable seamless tube of wall thickness less than 11/8" which has been heated to an austenization temperature of about 1,550° F. and simultaneously internally and externally quenched and tempered at substantially 1,140° F. and has a composition consisting essentially of 0.22 to 0.26% carbon, 1.20 to 1.4% manganese, not more than 0.035% phosphorus, not more than 0.02% sulphur, 0.15 to 0.35% silicon, 0.20 to 0.30% chromium, not more than 0.05% nickel, 0.15 to 0.20% molybdenum, 0.02 to 0.04% titanium, 0.0007 to 0.0025% boron, 0.007 to 0.050% aluminum and the balance iron and wherein said tube has a minimum ultimate tensile strength of 125,000 psi, yield strength of 115,000 to 135,000 psi, and elongation of 19% for a strip specimen and 15% for a round specimen and a hardness of 30-33 Rockwell C.
Claim 2
Dependent Claim
140 words
An electric furnace melted, vacuum degassed high strength weldable seamless tube of wall thickness less than 11/8" which has been heated to an austenization temperature of about 1,550° F. and simultaneously internally and externally quenched and tempered at substantially 1,140° F. and has a composition consisting essentially of 0.22 to 0.26% carbon, 1.20 to 1.4% manganese, not more than 0.035% phosphorus, not more than 0.02% sulphur, 0.15 to 0.35% silicon, 0.20 to 0.30% chromium, not more than 0.05% nickel, 0.15 to 0.20% molybdenum, 0.02 to 0.04% titanium, 0.0007 to 0.0025% boron, 0.007 to 0.050% aluminum and the balance iron and wherein said tube has a minimum ultimate tensile strength of 125,000 psi, yield strength of 115,000 to 135,000 psi, and elongation of 19% for a strip specimen and 15% for a round specimen and a hardness of 30-33 Rockwell C.
Claim 3
Dependent Claim
143 words
An electric furnace melted, vacuum degassed high strength weldable seamless tube of wall thickness equal to or greater than 11/8" which has been heated to an austenization temperature of about 1550° F. and simultaneously internally and externally quenched and tempered at about 1140° F. and has a composition consisting essentially of 0.24 to 0.28% carbon, 1.20 to 1.40% manganese, not more than 0.035% phosphorus, not more than 0.020% sulphur, 0.15 to 0.35% silicon, 0.20 to 0.30% chrominum, not more than 0.05% nickel, 0.40 to 0.60% molybdenum, 0.02 to 0.04% titanium, 0.0007 to 0.0025% boron, 0.007 to 0.050% aluminum and the balance iron and wherein said tube has a minimum ultimate tensile strength of 125,000 psi, yield strength of 115,000 to 135,000 psi, and elongation of 19% for a strip specimen and 15% for a round specimen and a hardness of 30-33 Rockwell C.
Claim 4
Dependent Claim
143 words
An electric furnace melted, vacuum degassed high strength weldable seamless tube of wall thickness equal to or greater than 11/8" which has been heated to an austenization temperature of about 1550° F. and simultaneously internally and externally quenched and tempered at about 1140° F. and has a composition consisting essentially of 0.24 to 0.28% carbon, 1.20 to 1.40% manganese, not more than 0.035% phosphorus, not more than 0.020% sulphur, 0.15 to 0.35% silicon, 0.20 to 0.30% chrominum, not more than 0.05% nickel, 0.40 to 0.60% molybdenum, 0.02 to 0.04% titanium, 0.0007 to 0.0025% boron, 0.007 to 0.050% aluminum and the balance iron and wherein said tube has a minimum ultimate tensile strength of 125,000 psi, yield strength of 115,000 to 135,000 psi, and elongation of 19% for a strip specimen and 15% for a round specimen and a hardness of 30-33 Rockwell C.
References Cited (Backward Citations)
JPS5597423A
Cited
US4282047A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-04-26 | 1991-10-26 | 1992-04-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-26 | 1995-10-26 | 1996-04-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-26 | 1999-10-26 | 2000-04-26 | $7700.00 | Window Closed / Lapsed |