Nippon Piston Ring Co., Ltd.

Honda Motor Co., Ltd.

Honda Giken Kogyo Kabushiki Kaisha

Arata Kakiuchi

Teruo Takahashi

Osamu Kawamura

Kenichi Sato

Tsutomu Saka

Katsuaki Sato

Katsuhiko Tominaga

Tomoki Okita

Masao Ishida

Hiroyuki Oketani

Masahiro Takehana

An iron-based sintered alloy material for a valve seat having improved wear resistance and reduced opposite aggressibility to a mating valve. The iron-based sintered alloy material contains 10% to 20% by area of first hard particles and 15% to 35% by area of second hard particles dispersed in a base matrix phase, the first and the second hard particles accounting for 25% to 55% by area in total. The first hard particles are composed of a cobalt-based intermetallic compound and have a size of 10 to 150 &#x3bc;m and a hardness of at least 500HV0.1 and less than 800HV0.1. The second hard particles are composed of a cobalt-based intermetallic compound and have a size of 10 to 150 &#x3bc;m and a hardness of at least 800HV0.1 and less than 1100HV0.1. Solid lubricant particles may also be dispersed in the base matrix phase.

Iron-based sintered alloy material for valve seat

A valve seat, press-fitted into a cylinder head of an internal combustion engine, containing an iron-based sintered alloy, includes a valve-seating section and a head-seating section. The valve-seating section and the head-seating section are monolithically formed by a sintering process and form a double layer structure. The valve-seating section includes a first iron-based sintered alloy member that has a porosity of 10 to 25 percent by volume and a sintered density of 6.1 to 7.1 g/cmand contains hard particles dispersed in a matrix. The head-seating section includes a second iron-based sintered alloy member that has a porosity of 10 to 20 percent by volume and a sintered density of 6.4 to 7.1 g/cm.

Sintered alloy valve seat and method for manufacturing the same

A valve seat made of an iron base sintered alloy for internal combustion engines comprises of hard particles of hardness 700-1300 Hv dispersed by 3-20% by volume in a matrix phase comprising comprising of a 5-40% psarlite phase, a 20-60% fine carbide dispersed phase, and a 5-20% high alloy diffusd phase. The hard paricles are preferably selected from a group of Mo--Ni--Cr--Si--Co intermetallic compound particles, Cr--Mo--Co intermetallic compound particles, and Fe--Mo alloy particles. The iron base sinteed alloy is conpised of, by weight, C: 0.2-2.0%, Cr: 1.0-9.0%, Mo: 1.0-9.0%, Si: 0.1-1.0%, W: 1.0-50%, V: 0.2-3.0%, one or more Cu, Co and Ni of 0.5-10.0% in total, and the remainder substantial Fe.

Abrasion resistant iron base sintered alloy material for valve seat and

The invention is directed to a joined type valve seat which is joined into the cylinder head of an aluminum alloy in an internal combustion engine by resistance welding and, in particular, to an improved joined type valve seat superior in strength, rigidity, and abrasion resistance, whereby no cracks are caused when running the engine or when joining the valve seat to the engine block by resistance welding. The valve seat is made of a material having a tensile strength of 300 MPa or above, a radial crushing strength of 500 MPa or above, an elongation of 0.6% or more, a thermal conductivity of 15 W/(m.multidot.K) or above, a coefficient of thermal expansion of 10.times.10-.sup.6 (1/K) or above, and an electric resistivity of 50 .mu..OMEGA..multidot.cm or below.

Joined type valve seat

A secondary hardening type high temperature wear-resistant sintered alloy body comprising 0.4 to 15 wt. % of at least one species of metal carbide forming element which is selected from the group consisting of W, Mo, V, Ti, Nb, Ta and B; 5 to 35 wt. % of at least one species of austenite forming element which is selected from the group consisting of Ni, Co, Cu, and Cr; 0.2 to 1.2 wt. % of C; and 0.04 to 0.2 wt. % of Al consisting essentially the remainder of Fe, wherein the alloy body contains an austenite phase which is capable of martensitic transformation.

Valve seat made of secondary hardening-type high temperature

A secondary hardening type high temperature wear-resistant sintered alloy body comprising 0.4 to 15 wt. % of at least one species of metal carbide forming element which is selected from the group consisting of W, Mo, V, Ti, Nb, Ta and B; 5 to 35 wt. % of at least one species of austenite forming element which is selected from the group consisting of Ni, Co, Cu, and Cr; 0.2 to 1.2 wt. % of C; and 0.04 to 0.2 wt % of the remainder consisting essentially of Fe wherein the alloy body contains an austenite phase which is capable of martensitic transformation.

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Shimotsuga, Japan

Arata Kakiuchi