Claims
- 1. A method of making a cutting insert comprising a cemented carbide body having a binder phase, with a binder phase enriched surface zone, and a binder phase depleted cutting edge, and a coating, comprising the steps of:forming a powder mixture containing WC, 2-10 wt. % Co, 4-12 wt. % of cubic carbides of metals from groups 4, 5 or 6 of the periodic table, the binder phase having a CW-ratio of 0.75-0.90; adding N in an amount of between 0.9 and 1.7% of the weight of the elements from groups 4 and 5; mixing said powder with a pressing agent; milling and spray drying the mixture to a powder material; compacting and sintering the powder material at a temperature of 1300-1500° C., in a controlled atmosphere of sintering gas at 40-60 mbar followed by cooling; applying post-sintering treatment; and applying a hard, wear resistant coating by CVD- or MT-CVD-technique.
- 2. The method of claim 1, wherein the powder mixture comprises 2-7 wt. % Co.
- 3. The method of claim 1, wherein the powder mixture comprises 7-10 wt. % of cubic carbides of the metals from groups 4, 5 or 6 of the periodic table.
- 4. The method of claim 1, wherein the powder mixture comprises more than 1 wt. % of each Ti cubic carbide, Ta cubic carbide and Nb cubic carbide.
- 5. The method of claim 1, wherein N is added in an amount between 1.1 and 1.4% of the weight of elements from groups 4 and 5.
- 6. The method of claim 1, wherein N is added to the powder mixture as a carbonitride.
- 7. The method of claim 1, wherein the N is added during the sintering step as part of the sintering gas atmosphere.
- 8. The method of claim 1, wherein the sintering is carried out at about 50 mbar.
- 9. The method of claim 1, wherein the hard, wear resistant coating is a 3-12 μm columnar TiCN layer followed by a 2-12 μm Al2O3.
- 10. The method of claim 1, wherein W is added to the powder mixture with the pressing agent, so as to achieve the CW-ratio of 0.75-0.90.
Priority Claims (1)
Number |
Date |
Country |
Kind |
9900403 |
Feb 1999 |
SE |
|
Parent Case Info
This application is a divisional of application Ser. No. 09/496,200, filed on Feb. 2, 2000, now U.S. Pat. No. 6,333,100 which issued on Dec. 25, 2001.
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