A sintered material containing a parent phase composed of a metal and a plurality of pores present in the parent phase, wherein the pores in a cross section have an average cross-sectional area of 500 μm.sup.2 or less, and the sintered material has a relative density in the range of 93% to 99.5%.

A sintered member including Fe as a main component thereof, includes a composition including Ni, Cr, Mo, and C, and a remainder including Fe and inevitable impurities, and a mixed-phase composition including a martensite phase and a residual austenite phase, wherein a Ni-content occupying the sintered member is larger than 2 mass % and less than or equal to 6 mass %, when a total content of elements included in the sintered member is regarded as 100 mass %, and a variation width of a Vickers hardness from a surface to a predetermined depth of the sintered member is less than or equal to 100 HV.

A three-dimensional printing kit can include a binding agent including a binder in a liquid vehicle and a particulate build material including from about 80 wt % to 100 wt % stainless steel particles having a D50 particle size from about 5 μm to about 125 μm. From about 75 wt % to 100 wt % of the stainless steel particles can be austenitic stainless steel particles including from about 10 wt % to about 12.3 wt % nickel, from about 10 wt % to about 20 wt % chromium, from about 1.5 wt % to about 4 wt % molybdenum, and up to about 0.08 wt % carbon. The austenitic stainless steel particles can have an equivalent nickel content from about 10 wt % to about 15.5 wt %.

A three-dimensional printing kit can include a binding agent including a binder in a liquid vehicle and a particulate build material including from about 80 wt % to 100 wt % stainless steel particles having a D50 particle size from about 5 μm to about 125 μm. From about 75 wt % to 100 wt % of the stainless steel particles can be austenitic stainless steel particles including from about 10 wt % to about 12.3 wt % nickel, from about 10 wt % to about 20 wt % chromium, from about 1.5 wt % to about 4 wt % molybdenum, and up to about 0.08 wt % carbon. The austenitic stainless steel particles can have an equivalent nickel content from about 10 wt % to about 15.5 wt %.

Disclosed is a mixed powder for powder metallurgy including: (a) an iron-based powder containing Si in an amount of 0 mass % to 0.2 mass % and Mn in an amount of 0 mass % to 0.4 mass %, with the balance being Fe and inevitable impurities; and (b) an alloyed steel powder containing Mo in an amount of 0.3 mass % to 4.5 mass %, Si in an amount of 0 mass % to 0.2 mass %, and Mn in an amount of 0 mass % to 0.4 mass %, with the balance being Fe and inevitable impurities, wherein a ratio of (b) the alloyed steel powder to a total of (a) the iron-based powder and (b) the alloyed steel powder is from 50 mass % to 90 mass %, and a ratio of Mo to the total of (a) the iron-based powder and (b) the alloyed steel powder is 0.20 mass % or more and less than 2.20 mass %.

A piston pin includes a pipe-shaped main body made of an iron-based sintered alloy. The piston pin is installed to penetrate an upper end of the connecting rod and the piston and the piston pin has an eccentric mass center in a circumferential direction.

A piston pin includes a pipe-shaped main body made of an iron-based sintered alloy. The piston pin is installed to penetrate an upper end of the connecting rod and the piston and the piston pin has an eccentric mass center in a circumferential direction.

A sintered material with a composition composed of an iron-based alloy and a structure in which the number of compound particles 0.3 μm or more in size is less than 200 per 100 μm×100 μm unit area in a cross section, wherein the sintered material has a relative density of 93% or more.

Disclosed is an alloyed steel powder for powder metallurgy from which sintered parts that do not contain expensive Ni, or Cr or Mn susceptible to oxidation, that have excellent compressibility, and that have high strength in an as-sintered state can be obtained. The alloyed steel powder for powder metallurgy has: a chemical composition containing Mo: 0.5 mass % to 2.0 mass % and Cu: 1.0 mass % to 8.0 mass %, with the balance being Fe and inevitable impurities; and a microstructure in which an FCC phase is present at a volume fraction of 0.5% to 10.0%.

Disclosed is an alloyed steel powder for powder metallurgy from which sintered parts that do not contain expensive Ni, or Cr or Mn susceptible to oxidation, that have excellent compressibility, and that have high strength in an as-sintered state can be obtained. The alloyed steel powder for powder metallurgy has: a chemical composition containing Mo: 0.5 mass % to 2.0 mass % and Cu: 1.0 mass % to 8.0 mass %, with the balance being Fe and inevitable impurities; and a microstructure in which an FCC phase is present at a volume fraction of 0.5% to 10.0%.