Abstract: A cladding alloy powder consisting of: 0.7 to 1.0 mass % C; 30 to 40 mass % Mo; 20 to 30 mass % Ni; 10 to 15 mass % Cr; and a balance including Co and unavoidable impurities, or consisting of: 0.2 to 0.5 mass % C; 30 to 40 mass % Mo; 20 to 30 mass % Ni; and a balance including Co and unavoidable impurities.

Abstract: Hard particles for blending as a starting material in a sintered alloy contain 20 to 40 mass % of molybdenum, 0.5 to 1.0 mass % of carbon, 5 to 30 mass % of nickel, 1 to 10 mass % of manganese, 1 to 10 mass % of chromium, 5 to 30 mass % of cobalt, 0.05 to 2 mass % of yttrium, and the balance being inadvertent impurities and iron.

Abstract: A method of producing a hollow casting is provided, by which the joinability of a cast base material and a hollow-forming member to each other can be enhanced while suppressing the generation of oxides of or blow holes on a casting base material. The method of producing the hollow casting comprises enveloping a hollow-forming member in a molten base-metal cast material. Specifically, the method comprises the steps of: producing a hollow-forming member with a material having a melting point higher than that of a base-metal cast material such that air-gap layers are formed within the surface layers of contact surfaces with which the molten metal comes into contact; coating the contact surfaces with a layer of the same metal as that of the base-metal cast material; and enveloping the hollow-forming member in the base-metal cast material by disposing the coated hollow-forming member within a mold and then pouring the molten base-metal cast material into the mold.

Abstract: A cladding alloy powder consisting of: 0.7 to 1.0 mass % C; 30 to 40 mass % Mo; 20 to 30 mass % Ni; 10 to 15 mass % Cr; and a balance including Co and unavoidable impurities, or consisting of: 0.2 to 0.5 mass % C; 30 to 40 mass % Mo; 20 to 30 mass % Ni; and a balance including Co and unavoidable impurities.

Abstract: There is provided an iron-based sintered material resistant to the metal fatigue developing from the voids therein functioning as the initial points and improved in the strength and machinability thereof. An iron-based sintered material, including a mixed structure of martensite, bainite, and pearlite and multiple voids formed in the mixed structure, wherein the ratio of martensite and bainite in the mixed structure is 70% or more; the ratio of martensite and/or bainite in the mixed structure forming the void surface is 90% or more; and the density of the iron-based sintered material is 7.4 g/cm3 or more.

Abstract: A process for producing ferrous sintered alloy according to the present invention is characterized in that it is equipped with: a compaction step of pressure compacting a raw-material powder in which an Fe-system powder is mixed with a reinforcement powder, thereby turning the raw-material powder into a powder compact; and a sintering step of heating this powder compact in an oxidation preventive atmosphere, thereby sintering the powder compact; and said reinforcement powder is an Fe—Mn—Si—C powder comprising an Fe alloy or an Fe compound that includes: Mn in an amount of from 58 to 70%; Si in an amount making a compositional ratio of the Mn with respect to the Si (i.e., Mn/Si) that is from 3.3 to 4.6; and C in an amount of from 1.5 to 3%; when the entirety is taken as 100% by mass. This Fe—Mn—Si—C powder is procurable inexpensively relatively; besides, ferrous sintered alloys, which are obtained using that, are better in terms of various characteristics than are conventional ferrous sintered alloys.

Abstract: Disclosed is a piston for internal-combustion engines, which includes a low thermal-conductive member disposed at the top portion thereof, the low thermal-conductive member including an alloy containing Fe and Mn. The low thermal-conductive member includes a sintered body having 10˜60 mass % of Mn, 2 mass % or less of C, and the balance of Fe and inevitable impurities. Since the piston has the low thermal-conductive member having low thermal conductivity and thermal expansion properties similar to those of the aluminum alloy, which is the base metal of the piston, an increase in the temperature of a combustion chamber and vaporization of fuel are effectively promoted. Furthermore, thermal fatigue failure and separation of the low thermal-conductive member are prevented.

Abstract: A ferrous sintered alloy includes a sintered raw-material powder that is made of an Fe—Cr—Mo-system powder, a carbon-system powder and an Mn—Si-system powder before sintering. The ferrous sintered alloy exhibits a density of 7.4 g/cm3 or more, and has a metallic structure that includes martensite and bainite. In the metallic structure, the martensite accounts for an area proportion of 40% or less when the entirety of the metallic structure is taken as 100% by area. Moreover, the martensite exhibits a particle diameter of 20 ?m or less. The ferrous sintered alloy is good in terms of machinability.

Abstract: A piston for internal combustion engine includes a piston body, and a low thermal conductor. The piston body has a top that faces a combustion chamber of the internal combustion engine. The low thermal conductor is disposed in the top of the piston body. Moreover, the low thermal conductor has a superficial portion, and an interior portion. The superficial portion faces the combustion chamber. The interior portion is disposed on a more inner side in the low thermal conductor than the superficial portion is. In addition, the superficial portion exhibits a first porosity. The interior portion exhibits a second porosity. The first porosity is smaller than the second porosity. Moreover, the low thermal conductor's superficial portion has a combustion-chamber-side surface that faces the combustion chamber and is subjected to shot peening.

Abstract: A piston for in-cylinder fuel-injection type internal combustion engine includes a piston body, a low thermal conductor, and a piston head. The low thermal conductor is disposed on the top of the piston body. The low thermal conductor includes a low thermally-conductive substrate, and a coating layer. The low thermally-conductive substrate has opposite surfaces. The coating layer includes alumina fine particles (Al2O3). The coating layer is adhered on at least a part one of the opposite surfaces of the low thermally-conductive substrate that makes a cast-buried or enveloped surface to be cast buried or enveloped in the piston head.

Abstract: Disclosed is a piston for internal-combustion engines, which includes a low thermal-conductive member disposed at the top portion thereof, the low thermal-conductive member including an alloy containing Fe and Mn. The low thermal-conductive member includes a sintered body having 10˜60 mass % of Mn, 2 mass % or less of C, and the balance of Fe and inevitable impurities. Since the piston has the low thermal-conductive member having low thermal conductivity and thermal expansion properties similar to those of the aluminum alloy, which is the base metal of the piston, an increase in the temperature of a combustion chamber and vaporization of fuel are effectively promoted. Furthermore, thermal fatigue failure and separation of the low thermal-conductive member are prevented.

Abstract: There is here disclosed an Fe-based sintered alloy produced through a mixing step of mixing an Fe—Mn alloy powder, graphite powder and Fe powder by a mixer (S16), a compacting step of compacting the mixed powder at a predetermined pressure (S18), and a sintering step of sintering the resultant compact in a sintering oven at a predetermined temperature for a predetermined time (S20), the Fe—Mn alloy powder being characterized by containing 2-30 mass % of Mn. In particular, the mixing step (S16) is carried out by mixing 5-50 mass % of the Fe—Mn alloy powder, 0.2-2 mass % of the graphite powder, and the remainder of the Fe powder in the mixer. Consequently, mechanical strength of the Fe-based sintered alloy can be further improved.

Abstract: There is provided an iron-based sintered material resistant to the metal fatigue developing from the voids therein functioning as the initial points and improved in the strength and machinability thereof. An iron-based sintered material, including a mixed structure of martensite, bainite, and pearlite and multiple voids formed in the mixed structure, wherein the ratio of martensite and bainite in the mixed structure is 70% or more; the ratio of martensite and/or bainite in the mixed structure forming the void surface is 90% or more; and the density of the iron-based sintered material is 7.4 g/cm3 or more.

Abstract: A hard particle having improved adhesion to a base material, a wear-resistant iron-base sintered alloy, a method of manufacturing the same, and a valve seat are provided. The hard particle comprises 20% to 70% Mo by mass, 0.2% to 3% C by mass, 1% to 15% Mn by mass, with the remainder being unavoidable impurities and Co. The sintered alloy comprises, as a whole, 4% to 35% Mo by mass, 0.2% to 3% C by mass, 0.5% to 8% Mn by mass, 3% to 40% Co by mass, with the remainder being unavoidable impurities and Fe. The alloy comprises a base material component comprising 0.2% to 5% C by mass, 0.1% to 10% Mn by mass, with the remainder being unavoidable impurities and Fe. The alloy further comprises a hard particle component comprising 20% to 70% Mo by mass, 0.2% to 3% C by mass, 1% to 15% Mn by mass, with the remainder being unavoidable impurities and Co. The hard particles are dispersed in the base material in an areal ratio of 10% to 60 %.

Abstract: To provide a sintered alloy capable of showing wear resistance and a process for producing the same as well as a valve seat of good wear resistance.

Abstract: A hard particle having improved adhesion to a base material, a wear-resistant iron-base sintered alloy, a method of manufacturing the same, and a valve seat are provided. The hard particle comprises 20% to 70% Mo by mass, 0.2% to 3% C by mass, 1% to 15% Mn by mass, with the remainder being unavoidable impurities and Co. The sintered alloy comprises, as a whole, 4% to 35% Mo by mass, 0.2% to 3% C by mass, 0.5% to 8% Mn by mass, 3% to 40% Co by mass, with the remainder being unavoidable impurities and Fe. The alloy comprises a base material component comprising 0.2% to 5% C by mass, 0.1% to 10% Mn by mass, with the remainder being unavoidable impurities and Fe. The alloy further comprises a hard particle component comprising 20% to 70% Mo by mass, 0.2% to 3% C by mass, 1% to 15% Mn by mass, with the remainder being unavoidable impurities and Co. The hard particles are dispersed in the base material in an areal ratio of 10% to 60 %.

Abstract: Hard particles are provided containing 20 to 70% of Mo, 0.5 to 3% of C, 5 to 40% of Ni, 1 to 20% of Mn, a balance in Fe, and impurities, where % represents percentage by mass, and may further contain at least one of 40% or less of Co, 0.1 to 10% of Cr, and 4% or less of Si. A wear resistant iron-based sintered alloy contains 4 to 30% of Mo, 0.2 to 3% of C, 1 to 20% of Ni, 0.5 to 12% of Mn, a balance in Fe, and impurities, with respect to the total mass of the iron-based sintered alloy as represented by 100%. In the sintered alloy, the base contains 0.2 to 5% of C, 0.1 to 12% of Mn, a balance in Fe, and impurities, with respect to the total mass of the base, and the hard particles contain 20 to 70% of Mo, 0.5 to 3% of C, 5 to 40% of Ni, 1 to 20% of Mn, a balance in Fe, and impurities, with respect to the total mass of the hard particles. The hard particles are dispersed in the base with an area ratio of 0.10 to 0.60. A method to produce a wear resistant sintered alloy of the above composition is also provided.

Abstract: Hard particles are provided containing 20 to 70% of Mo, 0.5 to 3% of C, 5 to 40% of Ni, 1 to 20% of Mn, a balance in Fe, and impurities, where % represents percentage by mass, and may further contain at least one of 40% or less of Co, 0.1 to 10% of Cr, and 4% or less of Si. A wear resistant iron-based sintered alloy contains 4 to 30% of Mo, 0.2 to 3% of C, 1 to 20% of Ni, 0.5 to 12% of Mn, a balance in Fe, and impurities, with respect to the total mass of the iron-based sintered alloy as represented by 100%. In the sintered alloy, the base contains 0.2 to 5% of C, 0.1 to 12% of Mn, a balance in Fe, and impurities, with respect to the total mass of the base, and the hard particles contain 20 to 70% of Mo, 0.5 to 3% of C, 5 to 40% of Ni, 1 to 20% of Mn, a balance in Fe, and impurities, with respect to the total mass of the hard particles. The hard particles are dispersed in the base with an area ratio of 10 to 60%. A method to produce a wear resistant sintered alloy of the above composition is also provided.

Abstract: An overlaying alloy containing no Cr or a reduced amount of Cr, in which an effective amount of Mo oxide is formed even in a weak oxidizing atmosphere such as a combustion atmosphere of diesel engines and engines using CNG, LPG or other gases as a fuel to provide an improved non-damaging property and wear resistance. An overlaying alloy comprising 20-70 wt % Mo, 0.5-3 wt % C, 5-40 wt % Ni, and the balance being Fe and unavoidable impurities, which contains no Cr to facilitate formation of Mo oxide and is advantageously applied to the parts on which an oxide coating is not easily formed such as the engine parts subject to a lower temperature combustion atmosphere. An overlaying alloy comprising 20-60 wt % Mo, 0.2-3 wt % C, 5-40 wt % Ni, 0.1-10 wt % Cr, and the balance of Fe and unavoidable impurities, which contains a small amount of Cr to control formation of Mo oxide and is advantageously applied to the parts on which an oxide coating is relatively easily formed.

Abstract: A cylinder head for an internal combustion engine includes a metallic cylinder head body, and a valve seat. The cylinder head body is provided with an inlet port, and an outlet port which are opened and closed by an inlet valve, and an outlet valve, respectively. The valve seat is disposed at an end of the inlet port or the outlet port, has a contact surface which is contacted with and separated from the inlet valve or the outlet valve, and is formed of a laminated substance. The laminated substance is formed as flakes by thermal spraying particles in a predetermined depositing direction, and the contact surface is inclined by an angle of from 0 to 60 degrees with respect to the depositing direction. In the cylinder head, the valve seat is strongly bonded to the cylinder head body, exhibits improved frictional characteristics on the contact surface, and has such high thermal conductivity in a depth-wise direction that it can be readily cooled to a low temperature.