Abstract: A powder for molding is a mixture of first constituent particles, which are made up of first metal base particles, and second constituent particles, which are made up of second metal base particles. A first lubricant concentration that is a mass proportion of a first internal lubricant adhered to the surface of the first metal base particles with respect to the total of the first constituent particles, is greater than a second lubricant concentration that is a mass proportion of a second internal lubricant that is adhered to the surface of the second metal base particles with respect to the total of the second constituent particles.

Abstract: An iron-based sintered alloy of the present invention is an iron-based sintered alloy, which is completed by sintering a powder compact made by press forming a raw material powder composed of Fe mainly, and is such that: when the entirety is taken as 100% by mass, carbon is 0.1-1.0% by mass; Mn is 0.01-1.5% by mass; the sum of the Mn and Si is 0.02-3.5% by mass; and the major balance is Fe. It was found out that, by means of an adequate amount of Mn and Si, iron-based sintered alloys are strengthened and additionally a good dimensional stability is demonstrated. As a result, it is possible to suppress or obsolete the employment of Cu or Ni, which has been believed to be essential virtually, the recyclability of iron-based sintered alloys can be enhanced, and further their cost reduction can be intended.

Abstract: A powder for molding is a mixture of first constituent particles, which are made up of first metal base particles, and second constituent particles, which are made up of second metal base particles. A first lubricant concentration that is a mass proportion of a first internal lubricant adhered to the surface of the first metal base particles with respect to the total of the first constituent particles, is greater than a second lubricant concentration that is a mass proportion of a second internal lubricant that is adhered to the surface of the second metal base particles with respect to the total of the second constituent particles.

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: 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: An iron-based sintered alloy of the present invention is an iron-based sintered alloy, which is completed by sintering a powder compact made by press forming a raw material powder composed of Fe mainly, and is such that: when the entirety is taken as 100% by mass, carbon is 0.1-1.0% by mass; Mn is 0.01-1.5% by mass; the sum of the Mn and Si is 0.02-3.5% by mass; and the major balance is Fe. It was found out that, by means of an adequate amount of Mn and Si, iron-based sintered alloys are strengthened and additionally a good dimensional stability is demonstrated. As a result, it is possible to suppress or obsolete the employment of Cu or Ni, which has been believed to be essential virtually, the recyclability of iron-based sintered alloys can be enhanced, and further their cost reduction can be intended.

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: An iron-based sintered alloy of the present invention is an iron-based sintered alloy, which is completed by sintering a powder compact made by press forming a raw material powder composed of Fe mainly, and is such that: when the entirety is taken as 100% by mass, carbon is 0.1-1.0% by mass; Mn is 0.01-1.5% by mass; the sum of the Mn and Si is 0.02-3.5% by mass; and the major balance is Fe. It was found out that, by means of an adequate amount of Mn and Si, iron-based sintered alloys are strengthened and additionally a good dimensional stability is demonstrated. As a result, it is possible to suppress or obsolete the employment of Cu or Ni, which has been believed to be essential virtually, the recyclability of iron-based sintered alloys can be enhanced, and further their cost reduction can be intended.