Manufacturing method for wear resistant sintered member, sintered valve seat, and manufacturing method therefor

1. A manufacturing method for a wear resistant sintered member, the method comprising:

compacting a raw powder containing a matrix forming powder and a hard phase forming powder into a green compact,

the matrix forming powder containing 90 mass % or more of a fine powder having a maximum particle diameter of 46 μm,

the matrix forming powder containing Fe as a main component, and

an amount of the hard phase forming powder being 50 to 70 mass % with respect to the raw powder; and

sintering the green compact,

wherein the hard phase forming powder consists of: all by mass %, 20 to 60% of Mo; 3 to 12% of Cr; 1 to 12% of Si; and the balance of Co and inevitable impurities.

2. The manufacturing method for the wear resistant sintered member according to claim 1 , wherein the hard phase forming powder forms a hard phase in which silicide is dispersed in an alloy phase by the sintering.

3. The manufacturing method for the wear resistant sintered member, according to claim 1 , wherein the matrix forming powder is a ferrous alloy powder containing 11 to 35 mass % of Cr.

4. The manufacturing method for the wear resistant sintered member, according to claim 3 , wherein the ferrous alloy powder further contains 3.5 to 22 mass % of Ni.

5. The manufacturing method for the wear resistant sintered member, according to claim 3 , wherein the matrix forming powder further contains at least one selected from a group consisting of all by mass %, 0.3 to 7% of Mo; 1 to 4% of Cu; 0.1 to 5% of Al; 0.3% or less of N; 5.5 to 10% of Mn; 0.15 to 5% of Si; 0.45 or less of Nb; 0.2% or less of P; 0.15% or less of S; and 0.15% or less of Se.

6. The manufacturing method for the wear resistant sintered member according to claim 1 , wherein the amount of the hard phase forming powder being 60 to 70 mass %, with respect to the raw powder.

7. A manufacturing method for a sintered valve seat, the method comprising:

preparing a matrix forming powder having the maximum particle diameter of 74 μm, a hard phase forming powder having the maximum particle diameter of 150 μm and consisting of 20 to 60 mass % of Mo, 3 to 12 mass % of Cr, 1 to 5 mass % of Si, and the balance of Co and inevitable impurities, and a graphite powder;

mixing 50 to 70 mass % of the hard phase forming powder, 0.8 to 2.0 mass % of the graphite powder, and the balance of the matrix forming powder to prepare a raw powder;

compacting the raw powder into a green compact; and

sintering the green compact,

wherein the matrix forming powder contains Fe as a main component, and

wherein the matrix forming powder contains 90 mass % or more of a fine powder having a maximum particle diameter of 46 μm, and the balance of the matrix forming powder has a maximum particle diameter of 74 μm.

8. The manufacturing method for the sintered valve seat according to claim 7 , wherein the matrix forming powder is at least one selected from the group consisting of the following (A) to (E):

(A) steel powder comprising 1.5 to 5 mass % of Mo, and the balance of Fe and inevitable impurities;

(B) steel powder comprising 2 to 4 mass % of Cr, 0.2 to 0.4 mass % of Mo, 0.2 to 0.4 mass % of V, and the balance of Fe and inevitable impurities;

(C) steel powder comprising 5.5 to 7.5 mass % of Co, 0.5 to 3 mass % of Mo, 0.1 to 3 mass % of Ni, and the balance of Fe and inevitable impurities;

(D) steel powder comprising 0.4 to 4 mass % of Mo, 0.6 to 5 mass % of Ni, 0.5 to 5 mass % of Cu, 0.05 to 2 mass % of Cr, 0.05 to 0.6 mass % of V, and the balance of Fe and inevitable impurities; and

(E) partially diffusion bonding alloy powder comprising 1 to 10 mass % of Ni, 1 to 3 mass % of Cu, 0.4 to 1.0 mass % of Mo, and the balance of Fe and inevitable impurities.

9. The manufacturing method for the sintered valve seat according to claim 8 , wherein the raw powder further contains 5 mass % or less of a nickel powder.

10. The manufacturing method for the sintered valve seat according to claim 8 , wherein the raw powder further contains 5 mass % or less of a copper powder.

11. The manufacturing method for the sintered valve seat according to claim 7 , wherein at least one sulfide powder selected from the group consisting of the following (F) to (I) is added to the raw powder such that amount of S in the raw powder is 0.04 to 5 mass %:

(F) molybdenum disulfide powder;

(G) tungsten disulfide powder;

(H) iron sulfide powder; and

(I) copper sulfide powder.

12. The manufacturing method for the sintered valve seat according to claim 11 , wherein at least one chromium containing steel powder having the maximum particle diameter of 150 μm selected from the group consisting of the following (J) to (N) is added as a lubricating phase forming powder to the raw powder at an amount of 5 to 20 mass %:

(J) chromium containing steel powder comprising 4 to 25 mass % of Cr, and the balance of Fe and inevitable impurities;

(K) chromium containing steel powder comprising 4 to 25 mass % of Cr, 3.5 to 22 mass % of Ni, and the balance of Fe and inevitable impurities;

(L) chromium containing steel powder comprising 4 to 25 mass % of Cr, 3.5 to 22 mass % of Ni, 0.3 to 7 mass % of Mo, 1 to 4 mass % of Cu, 0.1 to 5 mass % of Al, 0.3 mass % or less of N, 5.5 to 10 mass % of Mn, 0.15 to 5 mass % of Si, 0.45 mass % or less of Nb, 0.2 mass % or less of P, 0.15 mass % or less of S, and 0.15 mass % or less of Se, and the balance of Fe and inevitable impurities;

(M) chromium containing steel powder comprising 7.5 to 25 mass % of Cr, 0.3 to 3.0 mass % of Mo, 0.25 to 2.4 mass % of C, 0.2 to 2.2 mass % of V, 1.0 to 5.0 mass % of W, and the balance of Fe and inevitable impurities; and

(N) chromium containing steel powder comprising 4 to 6 mass % of Cr, 4 to 8 mass % of Mo, 0.5 to 3 mass % of V, 4 to 8 mass % of W, 0.6 to 1.2 mass % of C, and the balance of Fe and inevitable impurities.

13. The manufacturing method for the sintered valve seat according to claim 7 , wherein the raw powder further contains 2 mass % or less of at least one powder selected from the group consisting of manganese sulfide powder, calcium fluoride powder, boron nitride powder, magnesium meta-silicate mineral powder, bismuth powder, and bismuth oxide powder.

14. The manufacturing method for the sintered valve seat according to claim 7 , wherein lead, lead alloy, copper, copper alloy or acrylic resin is infiltrated or impregnated in pores of the sintered compact.

15. The manufacturing method for the sintered valve seat according to claim 7 , wherein the amount of the hard phase forming powder being 60 to 70 mass %, with respect to the raw powder.