Manufacturing method of sintered alloy, compact for sintering, and sintered alloy
Mixed powder that contains first hard particles, second hard particles, graphite particles, and iron particles is used to manufacture a sintered alloy. The first hard particle is a Fe—Mo—Cr—Mn based alloy particle, the second hard particle is a Fe—Mo—Si based alloy particle. The mixed powder contains 5 to 50 mass % of the first hard particles, 1 to 8 mass % of the second hard particles, and 0.5 to 1.0 mass % of the graphite particles when total mass of the first hard particles, the second hard particles, the graphite particles, and the iron particles is set as 100 mass %.
1. A manufacturing method of a sintered alloy comprising:
pressing mixed powder that contains first hard particles, second hard particles, graphite particles, and iron particles into a sintered-alloy compact; and
sintering the sintered-alloy compact while diffusing carbons in the graphite particles of the sintered-alloy compact into the first hard particles, the second hard particles, and the iron particles, wherein
the first hard particles contain 10 to 50 mass % of Mo, 3 to 20 mass % of Cr, 2 to 15 mass % of Mn, 1 mass % or less of C, and a remainder including Fe and inevitable impurities when the first hard particles have 100 mass %,
the second hard particles contain 60 to 70 mass % of Mo, 2 mass % or less of Si, and a remainder including Fe and inevitable impurities when the second hard particles have 100 mass %, and
the mixed powder contains 5 to 50 mass % of the first hard particles, 1 to 8 mass % of the second hard particles, and 0.5 to 1.0 mass % of the graphite particles when total mass of the first hard particles, the second hard particles, the graphite particles, and the iron particles is set as 100 mass %.
2. The manufacturing method according to claim 1 , wherein
a particle diameter of the second hard particle falls within a range of 75 μm and smaller.
3. The manufacturing method according to claim 1 , wherein
the sintered-alloy compact is heated and sintered at 1050 to 1250° C.
4. The manufacturing method according to claim 1 , wherein
the first hard particles contain 25 to 35 mass % of Mo, 5 to 10 mass % of Cr, 2 to 10 mass % of Mn, and 1 mass % or less of C when the first hard particles have 100 mass %.
5. The manufacturing method according to claim 1 , wherein
the remainder of the first hard particles and the remainder of the second hard particles are Fe and the inevitable impurities.
6. A compact for sintering comprising:
first hard particles that contain 10 to 50 mass % of Mo, 3 to 20 mass % of Cr, 2 to 15 mass % of Mn, 1 mass % or less of C, and a remainder including Fe and inevitable impurities when the first hard particles have 100 mass %;
second hard particles that contain 60 to 70 mass % of Mo, 2 mass % or less of Si, and a remainder including Fe and inevitable impurities when the second hard particles have 100 mass %;
graphite particles; and
iron particles, wherein
the first hard particles occupy 5 to 50 mass %, the second hard particles occupy 1 to 8 mass %, and the graphite particles occupy 0.5 to 1.0 mass % when total mass of the first hard particles, the second hard particles, the graphite particles, and the iron particles is set as 100 mass %.
7. The compact for sintering according to claim 6 , wherein
a particle diameter of the second hard particle falls within a range of 75 μm and smaller.
8. The compact for sintering according to claim 6 , wherein
the first hard particles contain 25 to 35 mass % of Mo, 5 to 10 mass % of Cr, 2 to 10 mass % of Mn, and 1 mass % or less of C when the first hard particles have 100 mass %.
9. The compact for sintering according to claim 6 , wherein
the remainder of the first hard particles and the remainder of the second hard particles are Fe and the inevitable impurities.
10. A sintered alloy obtained by sintering a compact comprising:
first hard particles that contain 10 to 50 mass % of Mo, 3 to 20 mass % of Cr, 2 to 15 mass % of Mn, 1 mass % or less of C, and a remainder including Fe and inevitable impurities when the first hard particles have 100 mass %;
second hard particles that contain 60 to 70 mass % of Mo, 2 mass % or less of Si, and a remainder including Fe and inevitable impurities when the second hard particles have 100 mass %;
graphite particles; and
iron particles, wherein
the first hard particles occupy 5 to 50 mass %, the second hard particles occupy 1 to 8 mass %, and the graphite particles occupy 0.5 to 1.0 mass % when total mass of the first hard particles, the second hard particles, the graphite particles, and the iron particles is set as 100 mass %, and
in the sintered alloy, carbon is diffused into the hard particles and the iron particles.