Abstract: An iron alloy powder consists of, when the entirety thereof is assumed to be 100 mass %, Cr: 2.5 mass % to 3.5 mass %, Mo: 0.4 mass % to 0.6 mass %, and Fe and inevitable impurities as the balance, a mixed powder consisting of 15 mass % to 40 mass % of the iron alloy powder, 1.2 mass % to 1.8 mass % of a copper powder, 0.5 mass % to 1.0 mass % of a graphite powder, and a pure iron powder as the balance when the entire mixed powder is assumed to be 100 mass % is compacted into a compact, and the compact is sintered while transforming a structure derived from the pure iron powder into a structure in which a ferritic structure and a pearlitic structure are mixed and transforming a structure derived from the iron alloy powder into a martensitic structure.

Abstract: A wear-resistant iron-based sintered alloy made of a mixed powder including first hard particles, second hard particles, graphite particles, and iron particles is produced. The first hard particles are Fe—Mo—Ni—Co—Mn—Si—C alloy particles. The second hard particles are Fe—Mo—Si alloy particles. The mixed powder includes the first hard particles at 5 mass % to 50 mass %, the second hard particles at 1 mass % to 8 mass %, and the graphite particles at 0.5 mass % to 1.5 mass % when a total amount of the above particles is set as 100 mass %. In a sintering process, sintering is performed so that the hardness of the first hard particles becomes 400 to 600 Hv and the hardness of the second hard particles exceeds 600 Hv. Then, an oxidation treatment is performed so that a density difference between before and after the oxidation treatment in a sintered product becomes 0.05 g/cm3 or more.

Abstract: An iron alloy powder consists of, when the entirety thereof is assumed to be 100 mass %, Cr: 2.5 mass % to 3.5 mass %, Mo: 0.4 mass % to 0.6 mass %, and Fe and inevitable impurities as the balance, a mixed powder consisting of 15 mass % to 40 mass % of the iron alloy powder, 1.2 mass % to 1.8 mass % of a copper powder, 0.5 mass % to 1.0 mass % of a graphite powder, and a pure iron powder as the balance when the entire mixed powder is assumed to be 100 mass % is compacted into a compact, and the compact is sintered while transforming a structure derived from the pure iron powder into a structure in which a ferritic structure and a pearlitic structure are mixed and transforming a structure derived from the iron alloy powder into a martensitic structure.