Patent US4336412A successfully refreshed from Google Patents.
US4336412A
Expired / Lapsed
US
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Heat treatment furnace
Assignee: Bulten Kanthal AB
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Filing: 1980-07-03
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Granted: 1982-06-22
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Expires: 2000-07-03
Abstract
Abstract Electrical heating furnaces for the treatment, e.g., of steel are provided with MoSi 2 -based resistance elements without an outer protective layer, even in the presence of a non-oxidating protective gas, for operation at about 800° to 1400° C.
Inventors
- 👤 Ture Thomander
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 16:20
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/10; H05B3/12; H05B3/14; H05B3/148; C; C21; C21D; C21D1/00; C21D1/74; C23; C23C; C23C8/00; C23C8/06; H05B2203/00; H05B2203/018
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
93 words
Heat treatment furnace comprising (a) a housing having a feed zone therein; (b) a plurality of electrical heating elements at least some of which are positioned in said feed zone; (c) means for introducing into said furnace a nonoxidizing atmosphere at maximally about 1050° C.; (d) at least those heating elements which are positioned in said feed zone comprising electrical resistance elements of substantially poreless material principally comprising molybdenum disilicide; and (e) said resistance elements being free of any protective coating in order to place them in unobstructed contact with said non-oxidizing atmosphere.
Claim 2
Dependent Claim
93 words
Heat treatment furnace comprising (a) a housing having a feed zone therein; (b) a plurality of electrical heating elements at least some of which are positioned in said feed zone; (c) means for introducing into said furnace a nonoxidizing atmosphere at maximally about 1050° C.; (d) at least those heating elements which are positioned in said feed zone comprising electrical resistance elements of substantially poreless material principally comprising molybdenum disilicide; and (e) said resistance elements being free of any protective coating in order to place them in unobstructed contact with said non-oxidizing atmosphere.
Claim 3
Dependent Claim
29 words
Heat treatment furnace according to claim 1, wherein said resistance elements are so arranged and dimensioned that they have a temperature during heat treatment of 800° to 1400° C.
Claim 4
Dependent Claim
22 words
Heat treatment furnace according to claim 2, wherein said resistance elements have a temperature during heat treatment of 900° and 1300° C.
Claim 5
Dependent Claim
21 words
Heat treatment furnace according to any one of claim 2, 3 or 1, wherein the atmosphere of said furnace is carburizing.
Claim 6
Dependent Claim
21 words
Heat treatment furnace according to any one of claim 2, 3 or 1, wherein the atmosphere of said furnace is carbo-nitriding.
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) | 1985-06-21 | 1985-12-21 | 1986-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-21 | 1989-12-21 | 1990-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-21 | 1993-12-21 | 1994-06-22 | $7700.00 | Window Closed / Lapsed |