Valve seat for internal combustion engines
AssigneeHitachi Powdered Metals Co., Ltd.
InventorsKoichiro Hayashi, Hideaki Kawata, Toru Tsuboi
Life of this patent
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Abstract
A valve seat is provided in which wear resistance can be ensured by optimizing the matrix structure without dispersing of expensive hard particles, and therefore the machinability can be improved and the holding down of cost can be achieved. The valve seat exhibits a metallographic structure consisting of only bainite single phase or only a mixed phase of bainite and martensite, has an area ratio of bainite and martensite in cross section of 100:0 to 50:50, and has a matrix hardness of 250 to 850 Hv.
Claims14
A valve seat for internal combustion engines comprising:
- 0.4 to 4% by weight of molybdenum:
- 0.2 to 1.1% by weight of carbon;
- at least one of 0.6 to 5% by weight of nickel,
- 0.5 to 5% by weight of copper,
- 0.05% to 2% by weight of chromium,
- 0.09 to 1% by weight of manganese and
- 0.05% to 0.6% by weight of vanadium;
- and
- the balance iron and inevitable impurities,
- wherein said valve seat exhibits a metallographic structure consisting of an iron-based matrix, said iron-based matrix is selected from the group consisting of a bainite single phase and a mixed phase of bainite and martensite, said banite and martensite are present in cross-section in a ratio of 100:0 to 50:50, and said iron-based matrix having a hardness of 250 to 850 Hv.
A valve seat for internal combustion engines consisting of:
- 0.4 to 4% by weight of molybdenum;
- 0.2 to 1.1% by weight of carbon;
- and
- the balance iron and inevitable impurities,
- wherein said valve seat exhibits a metallographic structure consisting of an iron-based matrix, said iron-based matrix is selected from the group consisting of a bainite single phase and a mixed phase of bainite and martensite, said banite and martensite are present in cross-section in a ratio of 100:0 to 50:50, and said iron-based matrix having a hardness of 250 to 850 Hv.
A valve seat for internal combustion engines consisting of:
- 0.4 to 4% by weight of molybdenum;
- 0.2 to 1.1% by weight of carbon;
- 0.1 to 1.5% by weigh of at least one of manganese sulfide,
- magnesium metasilicate mineral,
- calcium fluoride,
- boron nitride,
- molybdenum disulfide, and
- iron sulfide;
- and
- the balance iron and inevitable impurities,
- wherein said value seat exhibits a metallographic structure consisting of an iron-based matrix, said iron-based matrix is selected from the group consisting of a bainiate single phase and a mixed phase of bainite and martensite, said bainite and martensite are present in cross-section in a ratio of 100:0 to 50:50, said iron-based matrix having a hardness of 250 to 850 Hv, and said at least one of manganese sulfide, magnesium metasilicate mineral, calcium disulfide, boron nitride, molybdenum disulfide, and iron sulfide is dispersed in said metallographic structure as a particle.
Dependencies are inferred from the claim text.