US4734968A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for making a valve-seat insert for internal combustion engines
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1986-11-21
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Granted: 1988-04-05
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Expires: 2006-11-21
Abstract
Abstract A valve-seat insert for internal combustion engines comprises a double-layered, sintered alloy composed of a valve-seat layer on which a valve is seated, and a base layer integrated with the valve-seat layer and adapted to be seated in a cylinder head of an engine. The valve-seat layer is composed of a sintered alloy of a high heat resistance and a high wear resistance having a composition comprising, by weight, 4 to 8% Co, 0.6 to 1.5% Cr, 4 to 8% Mo, 1 to 3% Ni, 0.3 to 1.5% C, 0.2 to 0.6% Ca, and the balance of Fe and inevitable impurities, the additives, Co, Cr and Mo being present mainly in a form of a Co-Cr-Mo hard alloy and a hard Fe-Mo alloy dispersed in the Fe matrix. The base layer is composed of a sintered alloy of a higher heat resistance and a higher creep resistance than those of the valve-seat layer and having a composition comprising, by weight, 11 to 15% Cr, 0.4 to 2.0% Mo, 0.05 to 0.3% C, and the balance of Fe and inevitable impurities. At least the valve-seat layer of the double-layered, sintered alloy is being fusion-infiltrated with copper.
Inventors
- 👤 Nobuhito Kuroishi
- 👤 Naoki Motooka
- 👤 Tetsuya Suganuma
- 👤 Akira Manabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:11
CPC Classifications
F; F01; F01L; F01L3/00; F01L3/22; B; B22; B22F; B22F7/00; B22F7/06; C; C22; C22C; C22C33/00; C22C33/02; C22C33/0257; C22C33/0278; C22C33/0285; F02; F02B; F02B1/00; F02B1/02; F02B1/04; F02F; F02F1/00; F02F2001/008; Y; Y10; Y10S; Y10S29/00; Y10S29/031; Y10T; Y10T29/00; Y10T29/49; Y10T29/49229; Y10T29/49298; Y10T29/49306; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12771; Y10T428/12861; Y10T428/12937
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
249 words
A process for manufacturing a double layered valve-seat insert composed of a valve-seat layer and a base layer, comprising the steps of: preparing a mixture of raw materials for the valve-seat layer having a composition consisting essentially of, by weight, 4 to 8% Co, 0.5 to 1.5% Cr, 4 to 8% Mo, 1 to 3% Ni, 0.3 to 1.5% C, 0.2 to 0.6% Ca and the balance of Fe and inevitable impurities, said Co, Cr and Mo being present mainly in a form of a Co-Cr-Mo hard alloy and a Fe-Mo hard alloy dispersed in the Fe matrix of the valve seat layer; preparing separately and distinctly from the valve-seat raw material mixture a mixture of raw material for the base layer having a composition consisting essentially of, by weight, 11 to 15% Cr, 0.4 to 2.0% Mo, 0.05 to 0.3% C and the balance of Fe and inevitable impurities; pre-compacting the base layer mixture; compacting the base layer together with the valve-seat layer mixture to form a double layered green compact; sintering the green compact in a neutral or reducing atmosphere to form a double-layered sintered body; and infiltrating copper into the resulting double-layered sintered body by fusion, the fusion-infiltration of copper being carried out by heating the sintered body together with copper, so arranged that the valve-seat layer is in contact with copper, in a converted gas atmosphere at a temperature ranging from 1100° to 1150° C. to selectively infiltrate copper into the valve-seat layer by fusion.
Claim 2
Dependent Claim
249 words
A process for manufacturing a double layered valve-seat insert composed of a valve-seat layer and a base layer, comprising the steps of: preparing a mixture of raw materials for the valve-seat layer having a composition consisting essentially of, by weight, 4 to 8% Co, 0.5 to 1.5% Cr, 4 to 8% Mo, 1 to 3% Ni, 0.3 to 1.5% C, 0.2 to 0.6% Ca and the balance of Fe and inevitable impurities, said Co, Cr and Mo being present mainly in a form of a Co-Cr-Mo hard alloy and a Fe-Mo hard alloy dispersed in the Fe matrix of the valve seat layer; preparing separately and distinctly from the valve-seat raw material mixture a mixture of raw material for the base layer having a composition consisting essentially of, by weight, 11 to 15% Cr, 0.4 to 2.0% Mo, 0.05 to 0.3% C and the balance of Fe and inevitable impurities; pre-compacting the base layer mixture; compacting the base layer together with the valve-seat layer mixture to form a double layered green compact; sintering the green compact in a neutral or reducing atmosphere to form a double-layered sintered body; and infiltrating copper into the resulting double-layered sintered body by fusion, the fusion-infiltration of copper being carried out by heating the sintered body together with copper, so arranged that the valve-seat layer is in contact with copper, in a converted gas atmosphere at a temperature ranging from 1100° to 1150° C. to selectively infiltrate copper into the valve-seat layer by fusion.
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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) | 1991-04-05 | 1991-10-05 | 1992-04-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-05 | 1995-10-05 | 1996-04-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-05 | 1999-10-05 | 2000-04-05 | $7700.00 | Window Closed / Lapsed |