PcBN compact for machining of ferrous alloys

Patent metadata

Field	Value
Publication number	US-10406654-B2
Application number	US-201715793098-A
Country	US
Kind code	B2
Filing date	Oct 25, 2017
Priority date	Oct 25, 2017
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

The present application is a new improvement in the fine-grained cubic Boron Nitride sintered compact which may be employed to manufacture a cutting tool. The compact contains at least 80 vol % cBN and is sintered under HPHT conditions. The invention has lower levels of unreacted cobalt in the final sintered material than conventions materials. The invention has proved beneficial in the machining of ferrous metal alloys such as sintered metal alloys.

First claim

The invention claimed is:

1. A fine-grained sintered compact comprising:
a volume of between 80% and 95% by volume cBN particles;
a metallic binder comprising
Co, W, Al,
at least trace amount of each of W, CoW, WB, CoB, and
at least one of Cr, Ni, V, and Mn; and

a cemented carbide backing,
wherein Co not reacted with W or B is present in an amount of 1-3 vol % of the fine grained sintered compact.

2. The compact of claim 1 , wherein CoB represents between 3 vol % and 15 vol % of the fine grained sintered compact.

3. The compact of claim 1 , wherein the sintered compact has been sintered at HPHT conditions at a pressure of at least 5 GPa and a temperature of at least 1200° C.

4. The compact of claim 1 , wherein CoB is present in an amount of 3-15 vol % of the fine grained sintered compact, and WB is present in an amount of 0.1-10 vol % of the fine grained sintered compact, and wherein a ratio CoB/Co is 3-15, and a ratio CoB/WB is 0.5-15.

5. The compact of claim 1 , wherein the binder has a grain size of 0.3-0.7 micron as represented by D50.

6. The compact of claim 1 , wherein the cBN content is between 85 vol % and 95 vol % cBN.

7. The compact of claim 1 , wherein the cemented carbide backing is cemented WC.

8. The compact of claim 3 , wherein the HPHT pressure is at least 5.5 GPa.

9. The compact of claim 3 , where in the HPHT pressure is at least 6 GPa.

10. The compact of claim 1 , wherein the aluminum is from a source that comprises at least one of elemental aluminum or an aluminum intermetallic.

11. The compact of claim 10 , wherein the aluminum is from a source that comprises elemental aluminum, NiAl 3 , or TiAl 3 .

12. The compact of claim 1 , wherein the cobalt is from a source comprising the cemented carbide backing.

13. The compact of claim 12 , wherein the the cemented carbide backing is a cemented WC backing.

14. The compact of claim 1 , wherein the cBN particles have a D50 less than 5 microns.

15. The compact of claim 1 , wherein the compact is used as a component of a cutting tool.

16. The compact of claim 1 , wherein the cBN particles have a D50 less than 2 microns.

17. A fine-grained sintered compact comprising:
a volume of between 80% and 95% by volume cBN;
a metallic binder comprising Co, W, Al,
at least trace amount of each of W, CoW, WB, CoB, and
at least one of Cr, Ni, V, and Mn; and

a cemented carbide backing,
wherein CoB is present in an amount of 3-15 vol % of the fine grained sintered compact, unalloyed cobalt is present in an amount of 1-3 vol % of the fine grained sintered compact, and WB is present in an amount of 0.1-10 vol % of the fine grained sintered compact, and wherein a ratio CoB/Co is 3-15, and a ratio CoB/WB is 0.5-15.

18. The compact of claim 17 , wherein the compact is sintered at about 5 GPa.

19. The compact of claim 17 , wherein the compact is sintered at a temperature of at least 1200° C.

20. A method of manufacturing a fine-grained sintered compact comprising:
sintering a composition comprising
a volume of between 80% and 95% by volume cBN;
a metallic binder comprising
Co, W, Al,
at least trace amount of each of W, CoW, WB, CoB, and
at least one of Cr, Ni, V, and Mn,
wherein Co not reacted with W or B is present in an amount of 1-3 vol % of the fine grained sintered compact; and

a cemented carbide backing.

Assignees

• Diamond Innovations Inc

Inventors

• Dues Lawrence Thomas
• Yumoto Kenji

Classifications

• C04B2235/405

  Iron group metals · CPC title

• C04B2235/404

  Refractory metals · CPC title

• C04B2235/402

  Aluminium · CPC title

• C04B2235/40

  Metallic constituents or additives not added as binding phase · CPC title

• C04B35/5831 Primary

  based on cubic boron nitrides {or Wurtzitic boron nitrides, including crystal structure transformation of powder} · CPC title