Abstract: An iron-based sintered alloy valve seat insert for an internal combustion engine having excellent wear resistance, has a composition wherein Si—Cr—Ni—Fe type Mo-based intermetallic compound particles having a hardness of 700 to 1300 HV in terms of Vickers hardness and a composition containing Si: 1.5% to 3.5%, Cr: 7.0% to 9.0%, Mo: 35.0% to 45.0%, and Ni: 5.0% to 20.0% in terms of mass %, with a remainder being Fe and inevitable impurities are dispersed as hard particles in a base matrix phase that includes hard particles, solid lubricant particles, and contains C: 0.5% to 2.0%, Si: 0.2% to 2.0%, Mn: 5% or less, Cr: 0.5% to 15%, Mo: 3% to 20%, and Ni: 1 to 10% in terms of mass %, and further contains V: 0% to 5%, W: 0% to 10%, S: 0% to 2%, and Cu: 0% to 5%, with a remainder being Fe and inevitable impurities.

Abstract: The present invention relates to a hard particle powder for a sintered body, the powder including, in terms of mass %, 0.01?C?1.0, 2.5?Si?3.3, 0.1?Ni?20.0, 5.0?Cr?15.0, and 35.0?Mo?45.0, with the balance being Fe and inevitable impurities, in which the powder before performing sintering comprises an alloy phase comprising a hexagonal crystal structure of C14 type Laves phase.

Abstract: The present invention relates to a hard particle powder for a sintered body, the powder including, in terms of mass %, 0.01?C?1.0, 2.5?Si?3.3, 0.1?Ni?20.0, 5.0?Cr?15.0, and 35.0?Mo?45.0, with the balance being Fe and inevitable impurities, in which the powder before performing sintering comprises an alloy phase comprising a hexagonal crystal structure of C14 type Laves phase.

Abstract: A highly wear-resistant valve seat insert for an internal combustion engine, having a material composition in which hard-particles are uniformly and finely dispersed in the matrix phase, and which is excellent in wear-resistance and radial crushing strength, based on a blended fine powder and a matrix forming powder with a particle size approximately equal to that of the hard-particles so as to prevent the hard-particles from aggregating and thus coarsely dispersing as a hard-particle phase.

Abstract: In an assembly of a hollow poppet valve and a valve seat insert, the hollow poppet valve's head is integrally formed with a stem end, a hollow part is formed from the head to a stem, and coolant is filled into the hollow part along with an inert gas. The valve seat insert is formed of iron base sintered alloy and obtained by integrating two layers of a supporting material side layer and a valve contact face side layer. The hollow poppet valve is formed of a material having thermal conductivity of 5-45 (W/m·K) at 20-1000° C. The valve seat insert includes the supporting material side layer having thermal conductivity of 23-50 (W/m·K) at 20-300° C. and a valve contact face side layer having thermal conductivity of 10-22 (W/m·K) at 20-300° C. This enables a valve temperature decrease throughout an engine's entire RPM range compared with the prior art.

Abstract: Provided is a valve seat insert made of an iron-base sintered alloy, in which a base matrix part that includes a base matrix phase and hard particles, has a base matrix part composition containing, in % by mass, 0.5%-2.0% of carbon and 10%-70% in total of one kind or two or more kinds selected from nickel, cobalt, chromium, molybdenum, vanadium, tungsten, manganese, silicon and sulfur, with the balance being iron and unavoidable impurities, and Co-base hard particles having a composition containing, 1.0% or less of C, 25%-50% of Mo, 5%-15% of Cr, Si as an impurity in a content adjusted to be 0.3% or less, with the balance being Co, and having a Vickers hardness of 500 to 1,500 HV, are dispersed as hard particles in the base matrix phase in an amount of 10%-60% by mass with respect to the total amount of the valve seat insert.

Abstract: An iron-base sintered alloy material includes a matrix phase, Co base inter-metallic compound particles having hardness of 600 to 1200 HV, carbide-type particles having hardness of 400 to 700 HV, and optionally solid-lubricant particles, the particles being dispersed in the matrix phase. A matrix part including the matrix phase and the two kinds of hard-particles contains 0.3 to 1.5% by mass of C, and 10 to 50% by mass of one or more kinds selected from Si, Mo, Cr, Ni, Co, Mn, S, N, V, Ca, F, Mg, and O, the balance being Fe and unavoidable impurities. By dispersing, in the matrix phase, the Co base inter-metallic compound particles having high hardness, and the carbide-type particles having low hardness and low aggressiveness to mated material and increasing mechanical strength, wear-resistance can be improved with low aggressiveness to mated material and high radial crushing strength (350 MPa or more).

Abstract: Provided is a valve seat insert made of an iron-base sintered alloy, in which a base matrix part that includes a base matrix phase and hard particles, has a base matrix part composition containing, in % by mass, 0.5%-2.0% of carbon and 10%-70% in total of one kind or two or more kinds selected from nickel, cobalt, chromium, molybdenum, vanadium, tungsten, manganese, silicon and sulfur, with the balance being iron and unavoidable impurities, and Co-base hard particles having a composition containing, 1.0% or less of C, 25%-50% of Mo, 5%-15% of Cr, Si as an impurity in a content adjusted to be 0.3% or less, with the balance being Co, and having a Vickers hardness of 500 to 1,500 HV, are dispersed as hard particles in the base matrix phase in an amount of 10%-60% by mass with respect to the total amount of the valve seat insert.

Abstract: In an assembly of a hollow poppet valve and a valve seat insert, the hollow poppet valve's head is integrally formed with a stem end, a hollow part is formed from the head to a stem, and coolant is filled into the hollow part along with an inert gas. The valve seat insert is formed of iron base sintered alloy and obtained by integrating two layers of a supporting material side layer and a valve contact face side layer. The hollow poppet valve is formed of a material having thermal conductivity of 5-45 (W/m·K) at 20-1000° C. The valve seat insert includes the supporting material side layer having thermal conductivity of 23-50 (W/m·K) at 20-300° C. and a valve contact face side layer having thermal conductivity of 10-22 (W/m·K) at 20-300° C. This enables a valve temperature decrease throughout an engine's entire RPM range compared with the prior art.

Abstract: A highly wear-resistant valve seat insert is provided. When an iron-based powder, a hard-particle powder, and a graphite powder are mixed to obtain a mixed powder, for formation of a layer on a valve-contacting face side, the hard-particle powder having an average particle size 15-50 ?m, and the iron-based powder having an average particle size 15-50 ?m are blended so a matrix part composition after sintering is a composition containing C: 0.3 to 2.0% by mass, one or more kinds selected from Co, Si, Ni, Mo, Cr, Mn, S, W, and V at 70% by mass or less in total, the balance being Fe and unavoidable impurities and a matrix part structure after sintering is a structure which contains hard-particles at from 10 to 65% by mass with respect to a total amount of a layer on a valve-contacting face side and disperses the hard-particles at 1000 particles/mm2 or more.

Abstract: An iron-base sintered alloy material includes a matrix phase, Co base inter-metallic compound particles having hardness of 600 to 1200 HV, carbide-type particles having hardness of 400 to 700 HV, and optionally solid-lubricant particles, the particles being dispersed in the matrix phase. A matrix part including the matrix phase and the two kinds of hard-particles contains 0.3 to 1.5% by mass of C, and 10 to 50% by mass of one or more kinds selected from Si, Mo, Cr, Ni, Co, Mn, S, N, V, Ca, F, Mg, and O, the balance being Fe and unavoidable impurities. By dispersing, in the matrix phase, the Co base inter-metallic compound particles having high hardness, and the carbide-type particles having low hardness and low aggressiveness to mated material and increasing mechanical strength, wear-resistance can be improved with low aggressiveness to mated material and high radial crushing strength (350 MPa or more).