US4162157A
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US
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Secondary hardening steel having improved combination of hardness and toughness
Assignee: United States Department of Energy
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Filing: 1978-05-15
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Granted: 1979-07-24
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Expires: 1998-05-15
Abstract
Abstract A secondary hardening alloy steel composition consisting essentially of about 0.25-0.5% carbon, about 0.5-1.0% manganese, about 1.5-3.0% nickel, about 0-1.0% chromium, about 1.75-2.5% molybdenum, about 0-0.4% vanadium, and an additive selected from about 1-3% aluminum and a combination of at least about 1% aluminum and at least about 1% silicon for a combined Al+Si content of about 2-4%, the balance being iron and impurity elements. The present steel composition has the following characteristics: it exhibits a flat tempering response, it is hardenable upon tempering to a Rockwell C hardness of at least 50, and it has an improved combination of hardness vs. toughness properties after tempering in the secondary hardening range. A method of preparation is also described.
Inventors
- 👤 Earl R. Parker
- 👤 Victor F. Zackay
- 👤 Manjeshwar S. Bhat
- 👤 Warren M. Garrison, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:01
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/08
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
65 words
A secondary hardening alloy steel composition consisting essentially of about 0.25-0.5% carbon, about 0.5-1.0% manganese, about 1.5-3.0% nickel, about 0-1.0% chromium, about 1.75-2.5% molybdenum, about 0-0.4% vanadium, and an additive selected from about 1-3% aluminum and a combination of at least about 1% aluminum and at least about 1% silicon for a combined Al+Si content of about 2-4%, the balance being iron and impurity elements.
Claim 2
Dependent Claim
65 words
A secondary hardening alloy steel composition consisting essentially of about 0.25-0.5% carbon, about 0.5-1.0% manganese, about 1.5-3.0% nickel, about 0-1.0% chromium, about 1.75-2.5% molybdenum, about 0-0.4% vanadium, and an additive selected from about 1-3% aluminum and a combination of at least about 1% aluminum and at least about 1% silicon for a combined Al+Si content of about 2-4%, the balance being iron and impurity elements.
Claim 3
Dependent Claim
55 words
A secondary hardening alloy steel composition as in claim 1 wherein said composition is characterized by a flat tempering response, being hardenable on tempering to a hardness of at least 50 Rockwell C, and improved hardness versus toughness properties after tempering in a secondary hardening temperature range of between about 450° and about 600° C.
Claim 4
Dependent Claim
17 words
A secondary hardening alloy steel composition as in claim 1 wherein said additive is about 1-3% aluminum.
Claim 5
Dependent Claim
36 words
A secondary hardening alloy steel composition as in claim 1 wherein said additive is a combination of at least about 1% aluminum and at least about 1% silicon for a combined Al+Si content of about 2-4%.
Claim 6
Dependent Claim
84 words
A secondary hardening tempered martensitic alloy steel having a composition consisting essentially of about 0.25-0.5% carbon, about 0.5-1.0% manganese, about 1.5-3.0% nickel, about 0-1.0% chromium, about 1.75-2.5% molybdenum, about 0-0.4% vanadium, and an additive selected from the group consisting of about 1-3% aluminum and a combination of at least about 1% aluminum and at least about 1% silicon for a combined Al+Si content of about 2-4%, the balance being iron and impurity elements, said steel having a Rockwell C hardness of at least 50.
Claim 7
Dependent Claim
84 words
A secondary hardening tempered martensitic alloy steel having a composition consisting essentially of about 0.25-0.5% carbon, about 0.5-1.0% manganese, about 1.5-3.0% nickel, about 0-1.0% chromium, about 1.75-2.5% molybdenum, about 0-0.4% vanadium, and an additive selected from the group consisting of about 1-3% aluminum and a combination of at least about 1% aluminum and at least about 1% silicon for a combined Al+Si content of about 2-4%, the balance being iron and impurity elements, said steel having a Rockwell C hardness of at least 50.
Claim 8
Dependent Claim
27 words
A secondary hardening tempered martensitic alloy steel as in claim 5 wherein said alloy steel has a Charpy V-notch impact value of at least about 15 foot-pounds.
Claim 9
Dependent Claim
18 words
A secondary hardening tempered martensitic alloy steel as in claim 5 wherein said additive is about 1-3% aluminum.
Claim 10
Dependent Claim
37 words
A secondary hardening tempered martensitic alloy steel as in claim 5 wherein said additive is a combination of at least about 1% aluminum and at least about 1% silicon for a combined Al+Si content of about 2-4%.
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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) | 1982-07-23 | 1983-01-22 | 1983-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-07-23 | 1987-01-22 | 1987-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-07-23 | 1991-01-22 | 1991-07-24 | $7700.00 | Window Closed / Lapsed |