Specialized metallurgical processes – compositions for use therei – Compositions – Consolidated metal powder compositions
Patent
1988-02-16
1988-12-13
Terapane, John F.
Specialized metallurgical processes, compositions for use therei
Compositions
Consolidated metal powder compositions
75231, 419 47, C22C 2906
Patent
active
047908750
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a chromium-containing iron-base sintered alloy which is used as material for sliding parts in internal combustion engines, such as valve mechanisms.
BACKGROUND ART
Recently, the valve mechanisms of internal combustion engines have been required to bear heavy running loads. In particular, sliding parts, such as a camshafts and rocker arms, have been required to stand up against high plane pressures. Chromium-containing iron-base sintered alloys have been utilized in sliding parts not only to meet the aforementioned requirements but also to reduce the weight of the parts.
Such alloys are disclosed by JP A No. 54-62108, JP A No. 56-123353 (corresponding to U.S. Pat. No. 4,388,114) and JP A No. 58-37158. The alloy disclosed in 54-62108, contain, by weight, Cr, 8.0-30.0%; C, 0.5-4.0%; P, 0.2-0.3%, the balance being Fe. A problem arises with this alloy when the chromium exceeds 20.0% since the chromium-carbide grows coarser and harder which damages to opposing sliding parts. Another problem that arises is that it is too hard to be machined. The alloy of disclosed in No. 56-12353, contains, by weight, Cr, 2.5-7.5%; Cu, 1.0-5.0%; C, 1.5-3.5%; P, 0.2-0.8%; Si, 0.5-2.0%; Mn, 0.1-3.0%; Mo, less than 3.0%, the balance being Fe. This alloy is less shrinkable even when sintered at a liquid-phase since it contains more than 1% of copper. Thus, it is unavailable for fabricating the fitting members of a camshaft, such as cam lobes and the like, which are constrictively jointed to the shaft after being loosely mounted on the same. The alloy disclosed in No. 58-37158, contains, by weight, Cr, 2.5-25.0%; C, 1.5-3.5%; Mn, 0.1-3.0%; P, 0.1-0.8%; Cu, 1.0-5.0%; Si, 0.5-2.0%; Mo, less than 3.0%; S, 0.5-3.0%; Pb, 1.0-5.0%; the balance being Fe. This alloy has an advantage since copper is effective in preventing the growth of coarse chromium-carbide. However, it is relatively brittle because it contains sulphide and lead.
The present invention is intended to provide a chromium-containing iron-base sintered alloy that is superior in machinability and suitable for fabricating cam lobes and the like which are constrictively bonded to a shaft by liquid-phase sintering after being loosely mounted on the same shaft.
DISCLOSURE OF INVENTION
The liquid-phase sintered alloy according to the present invention contains, by weight, C, 1.5-4.0%; Si, 0.5-1.2%; Mn, no more than 1.0%; Cr, a range of 2.0% to less than 20.0%; Mo, 0.5%-2.5%; P, 0.2-0.8%, the balance being Fe. The alloy may have either of 0.5-2.5%, by weight, of nickel or no more than 0.85%, by weight, of copper, in addition to the aforementioned elements. It may additionally have 0.5-2.5%, by weight, of nickel along with 0.1-4.0%, by weight, of copper. It may contain other additional components, in the amount of 0.1-5.0%, by weight, selected from a group consisting of B, V, Ti, Nb and W.
The reason for a content range of 1.5-4.0% by weight of carbon is that, when the content of carbon exceeds 4.0%, the chromium-carbide grows coarser and harder which produces large pores and results in an alloy matrix that is somewhat brittle after being sintered, When carbon is below 1.5%, the amount of chromium-carbide is insufficient to give the abrasion-resistant property to the alloy.
The reason for a content range of 0.5-1.2% by weight of silicon is that, when silicon exceeds 1.2%, the alloy powders become less moldable and more deformable when sintered, causing the sintered alloy matrix to become brittle. silicone is an important component and yields a liquid-phase when carbon and phosphorus are relatively low in content, so that its content should not be less than 0.5%.
The reason for a content of no more than 1.0% by weight of manganese is that, when manganese exceeds 1.0%, the alloy powders become less moldable and the sintering rate reduces to such an extent that there remain large pores in the sintered alloy.
The reason for limiting the chromium content to less than 20.0% by weight is that more than 20.0% of chromium the chromium carbi
REFERENCES:
patent: 1252596 (1918-01-01), McMillin
patent: 2575218 (1951-11-01), Giles
patent: 2709132 (1955-05-01), Giles
patent: 3367770 (1968-02-01), Fletcher et al.
patent: 3692515 (1972-09-01), Fletcher et al.
patent: 3859083 (1975-01-01), Kusaka et al.
patent: 3977838 (1976-08-01), Hashimoto et al.
patent: 4035159 (1977-07-01), Hashimoto et al.
patent: 4110514 (1978-08-01), Nicholson
patent: 4125399 (1978-11-01), Kizu et al.
patent: 4150978 (1979-04-01), Schlatter et al.
patent: 4194906 (1980-05-01), Krantz et al.
patent: 4224060 (1980-09-01), de Souza et al.
patent: 4236923 (1980-12-01), Takahashi et al.
patent: 4243414 (1981-01-01), Takahashi et al.
patent: 4334926 (1982-06-01), Futamura et al.
patent: 4338128 (1982-07-01), Farge et al.
patent: 4345943 (1982-08-01), Takahashi et al.
patent: 4363662 (1982-12-01), Takahashi et al.
patent: 4388114 (1983-06-01), Suganuma et al.
patent: 4395284 (1983-07-01), Dawson
patent: 4433032 (1984-02-01), Nakamura et al.
patent: 4491477 (1985-01-01), Suganuma et al.
patent: 4505988 (1985-03-01), Urano et al.
Hirakawa Osamu
Urano Shigeru
Jorgensen Eric
Nippon Piston Ring Co. Ltd.
Terapane John F.
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