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CN-116635550-B - Coated cutting tool

CN116635550BCN 116635550 BCN116635550 BCN 116635550BCN-116635550-B

Abstract

The present invention relates to a coated cutting tool. The cutting tool is CVD coated and the substrate is a cemented carbide, wherein the metal binder in the cemented carbide comprises Ni. The CVD coating comprises an inner layer of TiN and a subsequent layer of TiCN.

Inventors

  • Linus von feiant
  • Laluka Brenning
  • Jan Nquist
  • Andreas Blume gram Vista
  • Eric Holmstern

Assignees

  • 山特维克科洛曼特公司

Dates

Publication Date
20260505
Application Date
20211122
Priority Date
20201126

Claims (17)

  1. 1. A coated cutting tool comprising a substrate of cemented carbide and a coating, wherein the cemented carbide consists of a metal binder and a hard component in the metal binder, Wherein the metal binder comprises 68 to 80 mole% Ni, 5 to 25 mole% Fe, 0 to 10 mole% Co, 4 to 15 mole% W, and Wherein the coating layer comprises an inner TiN layer and a TiCN layer in this order from the substrate, wherein the C activity with respect to graphite in the metal binder is less than 0.15, and the average d-electron value of the metal binder is 7.00 to 7.43, characterized in that The interface between the substrate and the TiN inner layer is free of Ti-containing intermetallic phases.
  2. 2. The coated cutting tool of claim 1, wherein the C activity in the metal binder is 0.095 to 0.120.
  3. 3. The coated cutting tool of claim 1 or 2, wherein an interface between the substrate and the TiN inner layer is free of Ti and Ni containing intermetallic phases.
  4. 4. The coated cutting tool of claim 1 or 2, wherein the interface between the substrate and TiN inner layer is free of Ti, fe and Ni containing intermetallic phases.
  5. 5. The coated cutting tool of claim 1 or 2, wherein the average d-electron value is from 7.25 to 7.43.
  6. 6. The coated cutting tool of claim 1 or 2, wherein the average d-electron value is from 7.36 to 7.43.
  7. 7. The coated cutting tool of claim 1 or 2, wherein the metal binder comprises 73 to 80 mole% Ni, 5 to 15 mole% Fe, 1 to 5 mole% Co, 8 to 13 mole% W.
  8. 8. The coated cutting tool of claim 1 or 2, wherein the metal binder content in the cemented carbide is 3 wt.% to 20 wt.%.
  9. 9. The coated cutting tool of claim 1 or 2, wherein the total thickness of the coating is 2 μιη to 20 μιη.
  10. 10. The coated cutting tool of claim 1 or 2, wherein the coating is a CVD coating.
  11. 11. The coated cutting tool of claim 1 or 2, wherein the TiN inner layer has a thickness of 0.1 μιη to 1 μιη, deposited on the cemented carbide substrate.
  12. 12. The coated cutting tool of claim 1 or 2, wherein the TiCN layer has a thickness of 6 μιη to 12 μιη.
  13. 13. The coated cutting tool of claim 1 or 2, wherein the coating comprises a layer of a-Al 2 O 3 located between the TiCN layer and the outermost surface of the coated cutting tool.
  14. 14. The coated cutting tool of claim 13, wherein the thickness of the a-ai 2 O 3 layer located between the TiCN layer and the outermost surface of the coated cutting tool is 4 μιη to 8 μιη.
  15. 15. The coated cutting tool of claim 13, wherein the α -Al 2 O 3 layer exhibits a texture coefficient TC (hk l) as defined according to the Harris formula, the texture coefficient TC (hk l) measured by X-ray diffraction using CuK α radiation and θ -2θ scanning, Where I (hkl) is the measured intensity of the (hkl) reflection, I 0 (hkl) is the standard intensity according to ICDD, PDF card number 00-010-0173, n is the number of reflections used in the calculation, where the (hkl) reflections used are (1 0 4), (1 1 0), (1 1 3), (0 2 4), (1 1 6), (2 4), (3 0 0) and (0 0 12), where TC (0 0 12). Gtoreq.6.
  16. 16. The coated cutting tool of claim 10, wherein the CVD coating further comprises one or more layers selected from TiN, tiCN, alTiN, zrCN, tiB 2 、Al 2 O 3 .
  17. 17. The coated cutting tool of claim 10, wherein the CVD coating further comprises a plurality of layers comprising a-Al 2 O 3 and/or k-Al 2 O 3 .

Description

Coated cutting tool Technical Field The present invention relates to a coated cutting tool comprising a substrate and a coating, wherein the substrate is a cemented carbide, wherein the metal binder in the cemented carbide comprises Ni. The coating is a CVD coating comprising an inner layer of TiN and a layer of TiCN. Background The market for cutting tools for chip forming metal cutting operations is dominated by CVD (chemical vapor deposition) coated and PVD (physical vapor deposition) coated cemented carbides, which are typically made of WC in a Co metal binder. Alternative metal binders are being developed that do not contain Co or contain reduced amounts of Co, but their products on the market remain rare or absent. In particular, during chemical vapor deposition using reactive gases at high temperatures, there is a high demand not only for the manufacture of cemented carbide itself, but also for the coating of cemented carbide due to the interaction between the gas phase and the cemented carbide. In the alternative metal binder, a mixture of Ni and Fe is a promising candidate, with these two elements being located on either side of Co in the periodic table. Ni shows high reactivity with Ti and high amounts of Ni in cemented carbides cause problems in chemical vapor deposition of Ti-containing coatings due to the formation of intermetallic phases such as Ni 3 Ti at the interface between the cemented carbide and the coating and in the coating. Intermetallic phases such as Ni 3 Ti in the interface or the interior of Ti-containing coatings can negatively affect the wear resistance of coatings subsequently deposited on Ti-containing coatings. Von Fieandt et al analyzed the problem of formation of Ni 3 Ti during deposition of TiN coatings on Ni metal substrates in "chemical vapor deposition of TiN on transition metal substrates" of surface and coating techniques 334 (2018) 373-383. It was concluded that Ni 3 Ti formation could be reduced during the CVD process by an excess N 2 partial pressure and a low H 2 partial pressure. It is an object of the present invention to provide a coated cutting tool for metal cutting having a Ni-containing cemented carbide substrate and a high performance wear resistant CVD coating. Another object is to provide a wear resistant coating comprising a TiN layer, a TiCN layer and a 001 oriented alpha-Al 2O3 on a cemented carbide substrate containing Ni, in particular a substrate containing a metal binder with more than 60 wt% Ni. Disclosure of Invention At least one of the above objects is achieved by a cutting tool according to item 1. Preferred embodiments are disclosed in the dependent claims. The present invention relates to a coated cutting tool comprising a substrate and a coating of cemented carbide, wherein the cemented carbide consists of a hard component in a metal binder, and wherein the metal binder comprises 68 to 80 mole% Ni, 5to 25 mole% Fe, 0to 10 mole% Co, 4 to 15 mole% W, and wherein the coating comprises in order from the substrate a TiN inner layer and a TiCN layer, wherein the C activity (carbon activity) in the metal binder relative to graphite is below 0.15 and the average d-electron value of the metal binder is 7.0 to 7.43, wherein the interface between the substrate and the TiN inner layer is free of Ti containing intermetallic phases. Surprisingly it was found that high quality TiN and TiCN can be deposited on cemented carbide substrates where the Ni content in the metal binder is high when the average d-electron value in the metal binder is 7.0 to 7.43 and the C-activity with respect to graphite is below 0.15. The coated cutting tool according to the present invention surprisingly shows fewer holes inside the coating, which is promising for wear resistant coatings for metal cutting applications. The TiN inner layer and the TiCN layer show improved properties with respect to the formation of intermetallic phases, pores, and disturbances related to the orientation of the layers and subsequently deposited layers. The technical effect may be increased flank wear resistance (FLANK WEAR RESISTANCE) and/or increased spalling resistance (FLAKING RESISTANCE) and/or increased crater wear resistance (CRATER WEAR RESISTANCE) in metal cutting operations such as steel. The composition of the metal binder in the cemented carbide has an effect on the quality of the layer deposited thereon by CVD, at least when depositing the Ti-containing layer. TiN is a very common initiation layer in cutting tool coatings. Without being bound by any theory, the inventors have concluded that during CVD deposition of TiN layers, N 2 molecules are believed to dissociate into N atoms/N radicals, which can then react and form TiN. However, ni in the surface increases the recombination rate of N 2 from N atoms/radicals, thereby passivating N and preventing dissociation of N atoms/radicals on the surface. TiN cannot be formed without N atoms/radicals. Instead, ti may react with Ni to form N