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US3661656A
Expired / Lapsed
US
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Case-hardened steel product and process for its manufacture
Assignee: Fagersta Bruks AB
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Filing: 1969-06-03
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Granted: 1972-05-09
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Expires: 1989-06-03
Abstract
Abstract The product comprises a tough core and at least one hard, carburized surface layer, the core containing 0.01-0.04% C, 2.26.0% Mn, 0.5-2.0% Si, up to 0.2% acid-soluble Al, 0.01-0.5% Nb and/or V, with Nb being replaceable by Ta, up to 0.03% N, up to 0.2% Zr, the balance being iron and impurities, the surface layer having a higher carbon content than the core but otherwise the same composition. The product is manufactured by shaping a blank of the aforesaid core composition, the shaping operation being followed by surface carburization and hardening.
Inventors
- 👤 Martin Holger Jarleborg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 12:59
CPC Classifications
C; C22; C22C; C22C38/00; C22C38/12; C22C38/04; C23; C23C; C23C8/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
20 words
The steel product according to claim 1 being of detachable rock drill bit having at least one carburized surface layer.
Claim 2
Dependent Claim
18 words
The steel product according to claim 1 being a gear-wheel having cogs wherein the surface layers are carburized.
Claim 3
Dependent Claim
113 words
A process for producing a case-hardened steel product made of a killed, manganese-alloyed steel blank consisting of: C 0.01-0.04 %; Mn 2.2-6.0 %; Si 0.5-2.0 %; Al (acid-soluble) up to 0.2 %; at least one element selected from the group consisting of Nb or V in an amount of from 0.01-0.5 %; and Nb being replaceable wholly or partially by Ta; N up to 0.03 %; and Zr up to 0.2 %; the balance being iron and ordinary impurities; comprising shaping the steel blank to the desired configuration of the product; carburizing at least onE of the surface layers of the shaped steel blank; and then hardening to form the desired steel product.
Claim 4
Dependent Claim
15 words
The process according to claim 4 wherein said hardening is followed by a tempering step.
Claim 5
Dependent Claim
14 words
The process according to claim 4 wherein said shaping step is a machining operation.
Claim 6
Dependent Claim
14 words
The process according to claim 4 wherein said shaping step is a pressing operation.
Claim 7
Dependent Claim
70 words
The steel product according to claim 1 wherein the composition consists of C 0.01-0.03 %; Mn 2.5-5.0 %; Si 0.7-1.5 %; A1 (acid-soluble) 0.01-0.1 %; at least one element selected from the group consisting of Nb or V in an amount of from 0.02-0.2 % and Nb being wholly or partially replaceable by Ta; N 0.005-0.02 %; and Zr up to 0.2 %; the balance being iron and ordinary impurities.
Claim 8
Dependent Claim
20 words
The steel product according to claim 8 being a detachable rock drill bit having at least one carburized surface layer.
Claim 9
Dependent Claim
18 words
The steel product according to claim 8 being a gear-wheel having cogs wherein the surface layers are carburized.
Claim 10
Dependent Claim
69 words
The process according to claim 4 wherein the composition consists of: C 0.01-0.03 %; Mn 2.5-5.0 %; Si 0.7-1.5 %; A1 (acid-soluble) 0.01-0.1 %; at least one element selected from the group consisting of Nb or V in an amount of from 0.02-0.2 % and Nb being wholly or partially replaceable by Ta; N 0.005-0.02 %; and Zr up to 0.2 %; the balance being iron and ordinary impurities.
Claim 11
Dependent Claim
15 words
The process according to claim 11 wherein said hardening is followed by a tempering step.
References Cited (Backward Citations)
US1990647A
Cited
US2219780A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-09 | 1975-11-08 | 1976-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-09 | 1979-11-08 | 1980-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-09 | 1983-11-08 | 1984-05-09 | $7700.00 | Window Closed / Lapsed |