Method for producing a powder-metallurgical product

Patent metadata

Field	Value
Publication number	US-11090720-B2
Application number	US-201916439695-A
Country	US
Kind code	B2
Filing date	Jun 12, 2019
Priority date	Jun 15, 2018
Publication date	Aug 17, 2021
Grant date	Aug 17, 2021

Abstract

A method for producing a powder-metallurgical product may include providing a powder mixture, forming the powder mixture into a green body, and sintering the green body to form a resulting powder-metallurgical product. The powder mixture may include a first hard phase, a second hard phase, 0 to 1.8% by weight of graphite, 0 to 5% by weight each of cobalt, tri-iron phosphide, copper, bronze, phosphorous, sulphur, calcium fluoride and molybdenum, 0.1 to 1.8% by weight of a pressing aid and a flow improver, and a remaining proportion that is an iron-base powder. The first hard phase may include 52 to 78% by weight of molybdenum, 0 to 2% by weight of silicon, 0 to 1.5% by weight of copper, and a remaining weight proportion of iron and production-related contaminations. The second hard phase may include 0 to 0.8% by weight of manganese and less than 0.1% by weight of carbon.

First claim

The invention claimed is:

1. A method for producing a powder-metallurgical product, comprising:
providing a powder mixture including:
a first hard phase, which includes 52 to 78% by weight of molybdenum, 0.4% to 2% by weight of silicon, 0 to 1.5% by weight of copper and a remaining weight proportion of iron and production-related contaminations;
a second hard phase including manganese, the second hard phase including 0.8% by weight or less of manganese and less than 0.1% by weight of carbon;
0 to 1.8% by weight of graphite;
0 to 5% by weight each of cobalt, tri-iron phosphide, copper, bronze, phosphorous, sulphur, calcium fluoride and molybdenum;
0.1 to 1.8% by weight of each of a pressing aid and a flow improver; and
a remaining proportion of a total weight of the powder mixture is an iron-base powder;

forming the powder mixture into a green body; and
sintering the green body to form a resulting powder-metallurgical product.

2. The method according to claim 1 , wherein one of:
the second hard phase further includes 25 to 30% by weight of molybdenum, 6 to 11% by weight of chromium, 2 to 4.5% by weight of silicon, 0 to 5% by weight of iron, and a remaining proportion of a total weight of the second hard phase is cobalt and production-related contaminations; and
the second hard phase further includes 26 to 32% by weight of molybdenum, 12 to 19% by weight of chromium, 2 to 5% by weight of silicon, 0 to 5% by weight of cobalt, and a remaining proportion of a total weight of the second hard phase is iron and production-relating contaminations.

3. The method according to claim 1 , wherein one of:
the first hard phase and the second hard phase in total amount to 10 to 45% of the total weight of the powder mixture and a ratio of a weight proportion of the first hard phase to a weight proportion of the second hard phase amounts to between 3 to 1 and 1 to 3; and
the first hard phase and the second hard phase in total amount to 22 to 40% of the total weight of the powder mixture and a ratio of a weight proportion of the first hard phase to a weight proportion of the second hard phase amounts to between 2 to 1 and 1 to 2.

4. The method according to claim 1 , wherein the iron-base powder includes at least one tool steel powder.

5. The method according to claim 1 , wherein 30 to 70% by weight of the iron-base powder is composed of a powder including 0.8 to 1.3% by weight of carbon, 3 to 5% by weight of chromium, 0 to 1% by weight of cobalt, 0 to 0.5% by weight of manganese, 3 to 7% by weight of molybdenum, 0 to 1% by weight of silicon, 2 to 4% by weight of vanadium, 5 to 7.5% by weight of tungsten, and a remaining proportion of a total weight of the powder is iron and production-related contaminations.

6. The method according to claim 1 , wherein forming the powder mixture into a green body includes uni-axial pressing the powder mixture to a green density of 6.3 g/cm 3 to 7.5 g/cm 3 .

7. The method according to claim 1 , further comprising infiltrating a plurality of pores in the green body with a copper base infiltrant when sintering the green body.

8. The method according to claim 1 , wherein the green body is sintered at a temperature of 1,065° C. to 1,195° C.

9. The method according to claim 1 , wherein at least one of:
the powder mixture includes 0.15% by weight to 5% by weight of tri-iron phosphide;
the powder mixture includes more than 0% by weight to 5% by weight of bronze; and
the powder mixture includes more than 0% by weight to 5% by weight of phosphorous.

10. The method according to claim 1 , wherein the powder mixture is formed into the green body via pressing.

11. The method according to claim 1 , wherein the resulting powder-metallurgical product is one of a bearing, a sealing element, a sliding element, a valve component, and a valve seat ring.

12. The method according to claim 1 , wherein a total weight of the resulting powder-metallurgical product includes 0.5 to 1.8% by weight of carbon, 2 to 9% by weight of chromium, 4 to 16% by weight of cobalt, 0 to 1.6% by weight of manganese, 10 to 22% by weight of molybdenum, 0 to 2% by weight of silicon, 0.5 to 6% by weight of vanadium, 1 to 8% by weight of tungsten, 5 to 25% by weight of copper, 0 to 2% by weight of calcium, 0 to 1.5% by weight of sulphur, 0 to 5% nickel, and a remaining proportion of the total weight of the resulting powder-metallurgical product is iron and production-related contaminations.

13. The method according to claim 1 , wherein a total weight of the resulting powder-metallurgical product includes 0.7 to 1.5% by weight of carbon, 2 to 5% by weight of chromium, 8 to 12% by weight of cobalt, 0 to 1% by weight of manganese, 12 to 18% by weight of molybdenum, 0 to 2% by weight of silicon, 1 to 3% by weight of vanadium, 2 to 4% by weight of tungsten, 10 to 20% by weight of copper, 0 to 0.5% by weight of calcium, 0 to 1% by weight of sulphur, 0 to 3% by weight of nickel, and a remaining proportion of the total weight of the resulting powder-metallurgical product is iron and production-related contaminations.

14. The method according to claim 1 , wherein the pressing aid and the flow improver collectively defined 1.8% by weight or less of the powder mixture.

15. The method according to claim 1 , wherein the powder mixture includes 0.15% by weight to 5% by weight of tri-iron phosphide.

16. The method according to claim 1 , wherein the powder mixture includes each of graphite, cobalt, tri-iron phosphide, copper, bronze, phosphorous, sulphur, calcium fluoride, molybdenum, the pressing aid, the flow improver, and the iron-base powder.

17. The method according to claim 1 , wherein:
the first hard phase and the second hard phase in total amount to 10 to 45% of the total weight of the powder mixture; and
a ratio of a weight proportion of the first hard phase to a weight proportion of the second hard phase is one of 3:1, 2:1, 1:2, and 1:3.

18. A method for producing a powder-metallurgical product, comprising:
providing a powder mixture;
forming the powder mixture into a green body; and
sintering the green body to form a resulting powder-metallurgical product;
wherein the powder mixture includes:
a first hard phase, which includes 52 to 78% by weight of molybdenum, 0 to 2% by weight of silicon, 0 to 1.5% by weight of copper and a remaining weight proportion of iron and production-related contaminations;
a second hard phase, which includes 0 to 0.8% by weight of manganese and less than 0.1% by weight of carbon;
0 to 1.8% by weight of graphite;
0 to 5% by weight each of cobalt, tri-iron phosphide, copper, bronze, phosphorous, sulphur, calcium fluoride and molybdenum;
0.1 to 1.8% by weight of each of a pressing aid and a flow improver; and
a remaining proportion of a total weight of the powder mixture is an iron-base powder; and

wherein 30 to 70% by weight of the iron-base powder is composed of a powder including 0.8 to 1.3% by weight of carbon, 3 to 5% by weight of chromium, 0 to 1% by weight of cobalt, 0 to 0.5% by weight of manganese, 3 to 7% by weight of molybdenum, 0 to 1% by weight of silicon, 2 to 4% by weight of vanadium, 5 to 7.5% by weight of tungsten, and a remaining proportion of a total weight of the powder is iron and production-related contaminations.

19. A method for producing a powder-metallurgical product, comprising:
providing a powder mixture including a first hard phase, a second hard phase, graphite, cobalt, tri-iron phosphide, copper, bronze, phosphorous, sulphur, calcium fluoride, molybdenum, a pressing aid, a flow improve

Assignees

• Mahle Int Gmbh

Inventors

• Heckendorn Heiko
• Ruch Roland
• Sutter Patrick
• Suetterle Rene
• Wintrich Klaus

Classifications

• C22C33/0278

  with at least one alloying element having a minimum content above 5% · CPC title

• B22F2303/45

  Part of a final mixture to be processed further · CPC title

• B22F2301/20

  Refractory metals · CPC title

• C22C38/002

  containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60 · CPC title

• B22F5/008 Primary

  of engine cylinder parts or of piston parts other than piston rings (of piston rings B22F5/02) · CPC title