阅读说明：本技术 涂层切削工具 (Coated cutting tool ) 是由 扬·恩奎斯特 埃里克·林达尔 于 2018-06-19 设计创作，主要内容包括：本发明涉及一种涂层切削工具,其中所述涂层包括由交替的κ-Al<Sub>2</Sub>O<Sub>3</Sub>子层和TiN、TiC、TiCN、TiCO或TiCNO子层组成的多层,所述多层包括至少3个κ-Al<Sub>2</Sub>O<Sub>3</Sub>子层。所述多层进一步在15°-140°的θ-2θ扫描上表现出XRD衍射,其中0 0 2衍射峰(峰面积)是源自所述多层的所述κ-Al<Sub>2</Sub>O<Sub>3</Sub>子层的最强峰。(The present invention relates to a coated cutting tool wherein the coating comprises a material consisting of alternating kappa-Al 2 O 3 A sublayer and a TiN, TiC, TiCN, TiCO or TiCNO sublayer, said multilayer comprising at least 3 kappa-Al sublayers 2 O 3 And a sublayer. The multilayer further exhibits XRD diffraction on a theta-2 theta scan of 15 ° -140 °, with the 002 diffraction peak (peak area) being derived from the kappa-Al of the multilayer 2 O 3 Strongest peak of sublayer.)

1. A coated cutting tool comprising a substrate and a coating, wherein the coating comprises

From alternating kappa-Al₂O₃Sublayer and TiN, TiC. A multilayer of TiCN, TiCO or TiCNO sublayers, said multilayer comprising at least 3 kappa-Al sublayers₂O₃The sub-layers are,

it is characterized in that

Said multilayer exhibits XRD diffraction on a theta-2 theta scan of 15 ° -140 °, with the 002 diffraction peak (peak area) being derived from said kappa-Al of said multilayer₂O₃Strongest peak of sublayer.

2. The coated cutting tool of claim 1, wherein each TiN, TiC, TiCN, TiCO, or TiCNO sublayer has an average thickness of 10-500 nm.

3. The coated cutting tool of claim 1 or 2, wherein each kappa-Al is₂O₃The average thickness of the sublayers is 30-900nm, preferably 50-800 nm.

4. The coated cutting tool of any of the preceding claims, further comprising alpha-Al between the substrate and the multilayer₂O₃And (3) a layer.

5. The coated cutting tool of claim 4, wherein the alpha-Al₂O₃The thickness of the layer is 0.1 to 10 μm, preferably 0.1 to 5 μm, more preferably 0.1 to 3 μm.

6. The coated cutting tool of any of the preceding claims, further comprising a layer of TiCN between the substrate and the multilayer.

7. The coated cutting tool of claim 6, wherein the TiCN layer has a thickness of 2-15 μm.

8. The coated cutting tool of claim 6 or 7, wherein the TiCN layer exhibits a texture coefficient TC (hkl), as measured by X-ray diffraction using CuKa radiation and theta-2 theta scanning, defined according to Harris' equation, which isWhere (hkl) is the intensity (peak area) of the measured (hkl) reflection facets, I (hkl) is₀(hkl) is the standard intensity according to PDF card number 42-1489 of ICDD, n is the number of reflection orders, and the reflection facets used in the calculation are (111), (200), (220), (311), (331), (420) and (422), where TC (422) + TC (311)>3, preferably>4。

9. The coated cutting tool of any of the preceding claims, wherein the kappa-Al is₂O₃The thickness of the multilayer is 1-15 μm.

10. The coated cutting tool of any of the preceding claims, wherein the total coating thickness is 2-9 μ ι η and the k-Al is₂O₃The multilayer comprises 5-70 kappa-Al₂O₃And a sublayer.

11. The coated cutting tool of any of the preceding claims, wherein the total coating thickness is 7-25 μ ι η and the k-Al₂O₃The multilayer comprises 5-150 kappa-Al₂O₃And a sublayer.

12. The coated cutting tool of any of the preceding claims, wherein the multiple layers are made of alternating kappa-Al₂O₃A sublayer and a TiN sublayer.

13. The coated cutting tool of any of the preceding claims, wherein the substrate is cemented carbide or cermet.

14. The coated cutting tool of any of the preceding claims, wherein the substrate is a cemented carbide, the composition of which comprises 4-12 wt-% Co, 0.1-10 wt-% cubic carbide, nitride or carbonitride of a metal from groups IVb, Vb and VIb of the periodic table, preferably Ti, Nb, Ta or combinations thereof, and balance WC.

Technical Field

The invention relates to a coated metal cutting tool comprising a multilayer with a kappa-alumina sublayer and a sublayer of TiN, TiC, TiCN, TiCO or TiCNO.

Background

Coated cutting tools are well known in the art in the metal cutting industry. CVD-coated cutting tools and PVD-coated cutting tools are the two most predominant types. The advantages of the coating on the cutting tool are effects such as increased chemical and abrasion resistance, which are important for providing a long tool life.

CVD coatings comprising a TiCN layer and a subsequent alumina layer are known to perform well. In certain demanding operations, the application of multiple CVD coatings has shown advantages.

EP0463000B1(Kennametal) discloses a multilayer coated cemented carbide cutting insert, wherein the multilayer comprises an aluminium oxide sub-layer and a nitride sub-layer. The aluminum oxide sublayer <1.5 μm and the nitride sublayer <1 μm. The cutting tool exhibits improved flank face and crater wear resistance in turning of SS1672 steel.

EP1245700B1(Seco) discloses a coated cutting tool having a multilayer of 3-30 μm comprising sublayers of 0.1-3.2 μm kappa alumina and 0.3-1.2 μm Ti (C, N). The cutting tool exhibits improved flank face and crater wear resistance in turning of SS1672 steel.

There has been an ongoing effort to provide cutting tools with better performance than previously known cutting tools. The technical solution differs depending on the operation and the workpiece material. Cutting tools intended for turning highly hardened steels are not optimized for stainless steel milling.

Disclosure of Invention

It is an object of the present invention to provide a coated cutting tool having improved wear resistance compared to known cutting tools. It is a further object of the invention to provide a cutting tool with improved performance in turning of hardened steels and non-alloyed steels. It is another object of the present invention to provide a cutting tool with improved crater and flank wear resistance in turning operations.

At least one of these objects is achieved with a cutting tool according to claim 1. Preferred embodiments are listed in the dependent claims.

The present invention relates to a coated cutting tool comprising a substrate and a coating, wherein the coating comprises a material consisting of alternating kappa-Al₂O₃A sublayer and a TiN, TiC, TiCN, TiCO or TiCNO sublayer, said multilayer comprising at least 3 kappa-Al sublayers₂O₃And a sublayer. Said multilayer exhibits XRD diffraction on a theta-2 theta scan of 15 ° -140 °, with the 002 diffraction peak (peak area) being derived from said kappa-Al of said multilayer₂O₃Strongest peak of sublayer.

It has surprisingly been found that in kappa-Al₂O₃In multilayers, high "00I orientation", i.e.from kappa-Al₂O₃The high reflection strength of the 00I crystal plane of the sub-layer (where I ═ 2, 4, 6, etc.) provides very promising wear resistance in turning of hardened steels.

The abbreviation "cutting tool" is intended herein to mean a cutting insert for milling or turning or a drill or end mill. The cutting tool is suitable for metal cutting applications.

In one embodiment of the invention each sublayer of TiN, TiC, TiCN, TiCO or TiCNO has an average thickness in the range of 10-500nm, preferably 50-200 nm. If these sub-layers are too thin, there is a risk that these layers will not completely cover the underlying layers, which will degrade the performance of the multilayer. On the other hand, if these layers are too thick, the properties of the layers will be comparable to a single layer.

In one embodiment of the invention, each kappa-Al is₂O₃The average thickness of the sublayers is 30-900nm, preferably 50-800nm, more preferably 100-700 nm. If these sub-layers are too thin, there is a risk that these layers will not completely cover the underlying layers, which will degrade the performance of the multilayer. On the other hand, if these layers are too thick, the properties of the layers will be comparable to a single layer.

In one embodiment of the invention, the coating further comprises alpha-Al between the substrate and the plurality of layers₂O₃And (3) a layer. alpha-Al under the multilayer₂O₃The layer shows the advantage that it is a promising way to increase the 00I orientation of subsequent multilayers.

In one embodiment of the present invention, the α -Al₂O₃The thickness of the layer is 0.1-10 μm, preferably 0.1-5 μm, more preferably 0.1-3 μm, most preferably 0.3-2 μm. If the alpha-Al is present₂O₃Too thin a layer will not follow the kappa-Al₂O₃Providing any increase in the 00I orientation of the sub-layer. If the alpha-Al is present₂O₃If the layer is too thick, e.g. more than 10 μm, the properties of the coating become brittle.

In one embodiment of the invention, the coating further comprises a layer of TiCN between the substrate and the plurality of layers. In one embodiment of the invention, the TiCN layer is located between the substrate and the alpha-Al₂O₃Between the layers. The TiCN layer preferably comprises columnar grains. The TiCN layer is advantageous in that it contributes to the wear resistance of the cutting tool and also to the orientation in which the TiCN layer can be formed during growth, which is advantageous for the orientation of subsequent layers.

In one embodiment of the invention, the TiCN layer has a thickness of 2 to 15 μm. If the TiCN layer is too thin, the advantage of forming high orientation is reduced. If the TiCN layer is too thick, the coating will become brittle.

In one embodiment of the invention, the TiCN layer exhibits a texture coefficient tc (hkl), measured by X-ray diffraction using cuka radiation and theta-2 theta scanning, defined according to harris' formula, where I (hkl) is the measured intensity (peak area) of the (hkl) reflecting facets, I (hkl) is the intensity of the measured (hkl) reflecting facets₀(hkl) is the standard intensity according to PDF card number 42-1489 of ICDD, n is the number of reflection orders, and the reflection planes used in the calculation are (111), (200), (220), (311), (331), (420) and (422), where TC (422) + TC (311)>3, preferably>4. Harris formula:

wherein I (hkl) is the intensity (peak area) of the measured (hkl) reflection facets, and I (hkl) is₀(hkl) is the standard strength according to the PDF card.

In one embodiment of the invention, the thickness of the multilayer is 1 to 15 μm, preferably 1 to 10 μm, more preferably 1 to 5 μm. If the multiple layers are thinner than 1 μm, the wear resistance of the coated cutting tool will be less pronounced. On the other hand, if the multilayer is too thick, the coating will become brittle and the advantages of the multilayer are less pronounced.

In one embodiment of the invention, the total coating thickness is 2-9 μm, and the kappa-Al is₂O₃The multilayer comprises 5-70 kappa-Al₂O₃And a sublayer. Such an embodiment is suitable for milling or drilling metal cutting applications.

In one embodiment of the invention, the total coating thickness is 7-25 μm, and kappa-Al₂O₃The multilayer comprises 5-150 kappa-Al₂O₃And a sublayer. Such an embodiment is suitable for turning metal cutting applications.

In one embodiment of the invention, the multiple layers are made of alternating kappa-Al₂O₃A sublayer and a TiN sublayer. The TiN sublayer is preferably (111) oriented such that the interatomic distance is related to the subsequent (00I) oriented kappa-Al₂O₃The sublayers are appropriately matched. This affects the orientation and residual stress of the sublayers.

In one embodiment of the invention, the substrate is cemented carbide or cermet. These substrates have a hardness and toughness suitable for the coatings of the present invention.

In one embodiment of the invention, the substrate of the coated cutting tool consists of cemented carbide comprising 4-12 wt.% Co, preferably 6-8 wt.% Co, optionally 0.1-10 wt.% cubic carbide, nitride or carbonitride of metals from groups IVb, Vb and VIb of the periodic table, preferably Ti, Nb, Ta or combinations thereof, and balance WC.

Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings.

Drawings

Fig. 1 shows a Scanning Electron Microscope (SEM) image of the coating according to sample a.

Fig. 2 shows a Scanning Electron Microscope (SEM) image of the coating according to sample B.

Figure 3 shows the theta-2 theta XRD diffractogram of sample a. The intensity is not corrected.

Figure 4 shows the theta-2 theta XRD diffractogram of sample D. The intensity is not corrected.

Method of producing a composite material

XRD examination

One common method of analyzing polycrystalline film texture is to calculate Texture Coefficients (TC) based on harris' formula and a standard intensity PDF card. However, since kappa-Al₂O₃Has low symmetry and thus many peaks of low intensity exist in the diffraction pattern, and thus it is difficult to determine κ -Al by calculation of the texture coefficient₂O₃Out-of-plane texture of multiple layers. There are also many overlapping peaks. Thus, kappa-Al is chosen here₂O₃The peak of highest intensity of the multilayer is taken as a measure of the texture of the layer.

In the analysis of kappa-Al₂O₃When orienting the sublayers, the data should typically be thin-film corrected to account for linear absorption in the sublayers. Ideally, the data should also be corrected for absorption in the TiN, TiC, TiCN, TiCO, TiCNO sublayers. However, the low thickness of the sub-layers and the high number of sub-layers make these corrections cumbersome. Due to the kappa-Al of the invention₂O₃The sublayers provide a very strong 00I orientation and since the effect of this correction is limited, this correction is not applied to the XRD data. kappa-Al of the present invention₂O₃The texture of the sublayers is set on the basis of uncorrected data, i.e., for the kappa-Al of the multilayer₂O₃The absorption in the sub-layer or the absorption in the multilayer TiN, TiC, TiCN, TiCO and TiCNO sub-layers is compensated. In this sense, a multilayer is considered to be a single layer. However, as is well known to those skilled in the art, background scatter and overlapping peaks are corrected for.

In analyzing the orientation of any layer below the multilayer, a thin film correction should be made for the peak intensity taking into account the linear absorption coefficient of the layer. The absorption in the multilayer can be classified by summarizing the thicknesses of the sublayers of the same composition into a single layer and calculating based on these thicknesses and their absorption.

Possible further layers above the multilayer, for example, will influence the X-ray intensity entering the multilayer and leaving the entire coating, and these need to be corrected in view of the linear absorption coefficients of the respective compounds in the layers. Alternatively, any other layers such as TiN over the multilayer may be removed by a method that does not substantially affect the XRD measurements, for example chemical etching.

Detailed Description

The present invention relates to a coated cutting tool comprising a substrate and a coating, wherein the coating comprises a material consisting of alternating kappa-Al₂O₃A sublayer and a TiN, TiC, TiCN, TiCO or TiCNO sublayer, said multilayer comprising at least 3 kappa-Al sublayers₂O₃And a sublayer. The multilayer exhibits XRD diffraction on a theta-2 theta scan of 15 DEG to 140 DEG, with the 002 diffraction peak (peak area) being derived from the kappa-Al of the multilayer₂O₃Strongest peak of sublayer.

It has surprisingly been found that in kappa-Al₂O₃In multilayers, high "00I orientation", i.e.from kappa-Al₂O₃The high reflection strength of the 00I crystal plane of the sub-layer (where I ═ 2, 4, 6, etc.) provides very promising wear resistance in turning of hardened steels.

The abbreviation "cutting tool" is intended herein to mean a cutting insert for milling or turning or a drill or end mill. The cutting tool is suitable for metal cutting applications.

In one embodiment of the invention each sublayer of TiN, TiC, TiCN, TiCO or TiCNO has an average thickness in the range of 10-500nm, preferably 50-200 nm. If these sub-layers are too thin, there is a risk that the layers do not completely cover the underlying layers, which will degrade the performance of the multilayer. On the other hand, if these layers are too thick, the properties of the layers will be comparable to a single layer.

In one embodiment of the invention, each kappa-Al is₂O₃The average thickness of the sub-layers is 30-900nm, preferablyPreferably 50-800nm, more preferably 100-700 nm. If these sub-layers are too thin, there is a risk that these layers will not completely cover the underlying layers, which will degrade the performance of the multilayer. On the other hand, if these layers are too thick, the properties of the layers will be comparable to a single layer.

In one embodiment of the invention, the coating further comprises alpha-Al between the substrate and the plurality of layers₂O₃And (3) a layer. alpha-Al under the multilayer₂O₃The layer shows the advantage that it is a promising way to increase the 00I orientation of subsequent multilayers.

In one embodiment of the present invention, the α -Al₂O₃The thickness of the layer is 0.1-10 μm, preferably 0.1-5 μm, more preferably 0.1-3 μm, most preferably 0.3-2 μm. If the alpha-Al is present₂O₃Too thin a layer will not provide subsequent kappa-Al₂O₃Any increase in the 00I orientation of the sublayers. If alpha-Al is present₂O₃If the layer is too thick, e.g. more than 10 μm, the properties of the coating become brittle.

In one embodiment of the invention, the coating further comprises a layer of TiCN between the substrate and the plurality of layers. In one embodiment of the invention, the TiCN layer is located between the substrate and the alpha-Al₂O₃Between the layers. The TiCN layer preferably comprises columnar grains. The TiCN layer is advantageous in that it contributes to the wear resistance of the cutting tool and also to the orientation in which the TiCN layer can be formed during growth, which is advantageous for the orientation of subsequent layers.

In one embodiment of the invention, the TiCN layer has a thickness of 2 to 15 μm. If the TiCN layer is too thin, the advantage of forming high orientation is reduced. If the TiCN layer is too thick, the coating will become brittle.

In one embodiment of the invention, the TiCN layer exhibits a texture coefficient tc (hkl), measured by X-ray diffraction using cuka radiation and theta-2 theta scanning, defined according to harris' formula, where I (hkl) is the measured intensity (peak area) of the (hkl) reflecting facets, I (hkl) is the intensity of the measured (hkl) reflecting facets₀(hkl) is the standard intensity according to ICDD PDF card number 42-1489, n is the number of reflection orders, and the reflection facets used in the calculation are (111) (200), (220), (311), (331), (420) and (422), wherein TC (422) + TC (311)>3, preferably>4。

In one embodiment of the invention, the thickness of the multilayer is 1 to 15 μm, preferably 1 to 10 μm, more preferably 1 to 5 μm. If the multiple layers are thinner than 1 μm, the wear resistance of the coated cutting tool will be less pronounced. On the other hand, if the multilayer is too thick, the coating will become brittle and the advantages of the multilayer are less pronounced.

In one embodiment of the invention, the total coating thickness is 2-9 μm, and the kappa-Al is₂O₃The multilayer comprises 5-70 kappa-Al₂O₃And a sublayer. Such an embodiment is suitable for milling or drilling metal cutting applications.

In one embodiment of the invention, the total coating thickness is 7-25 μm, and kappa-Al₂O₃The multilayer comprises 5-150 kappa-Al₂O₃And a sublayer. Such an embodiment is suitable for turning metal cutting applications.

In one embodiment of the invention, the multiple layers are made of alternating kappa-Al₂O₃A sublayer and a TiN sublayer. The TiN sublayer is preferably (111) oriented such that the interatomic distance is aligned with the subsequent (00I) oriented kappa-Al₂O₃The sublayers are appropriately matched. This affects the orientation and residual stress of the sublayers.

In one embodiment of the invention, the substrate is cemented carbide or cermet. These substrates have a hardness and toughness suitable for the coatings of the present invention.

In one embodiment of the invention, the substrate of the coated cutting tool consists of cemented carbide comprising 4-12 wt.% Co, preferably 6-8 wt.% Co, optionally 0.1-10 wt.% cubic carbide, nitride or carbonitride of metals from groups IVb, Vb and VIb of the periodic table, preferably Ti, Nb, Ta or combinations thereof, and balance WC.

In one embodiment of the invention, the substrate is comprised of cemented carbide having a binder phase enriched surface zone. The thickness of the binder phase enriched surface zone is preferably 5-35 μm, measured from the surface of the substrate towards the core of the substrate. The binder phase content of the binder phase-enriched zone is at least 50% higher than the binder phase content in the core of the substrate on average. The binder phase enriched surface zone enhances the toughness of the substrate. Substrates with high toughness are preferred in cutting operations such as turning of steel.

In one embodiment of the invention, the substrate is comprised of cemented carbide having a surface region substantially free of cubic carbides. The thickness of the surface region substantially free of cubic carbides, measured from the surface of the base material towards the core of the base material, is preferably 5-35 μm. By "substantially free" is meant that no cubic carbides are visible in visual analysis of the cross-section using an optical microscope.

In one embodiment of the invention, the substrate consists of a cemented carbide having a binder phase enriched surface zone as disclosed above and a surface zone substantially free of cubic carbides as disclosed above.

In one embodiment of the invention, kappa-Al₂O₃The layer is the outermost layer of the coating. Alternatively, one or more other layers may cover the multilayer, e.g. TiN, TiC, Al₂O₃Layers and/or combinations thereof. In one embodiment of the invention, one or more other layers covering the multiple layers are removed from the flank face or the rake face or the cutting edge or a combination thereof.

In one embodiment of the invention, the coating is post-treated by sandblasting or brushing to relieve the tensile stress of the CVD coating and reduce the surface roughness.

In one embodiment of the invention, the coating comprises alpha-Al₂O₃Layer of the alpha-Al₂O₃The layer is highly oriented with the 00I crystal plane parallel to the substrate surface. In one embodiment, alpha-Al₂O₃The layer exhibits a texture coefficient TC (hkl) defined according to the Harris formula by X-ray diffraction measurement using CuKa radiation and theta-2 theta scanning,

wherein I (hkl) is the measured intensity (peak area) of the (hkl) reflection facets, I (hkl) is₀(hkl) is the standard intensity according to the PDF card number 00-010-0173 of ICDD, n is the number of reflection orders used in the calculation, and wherein the (hkl) reflection facets used are (104), (110), (113), (024), (116), (214), (300) and (0012), wherein TC (0012) ≧ 2, preferably>4, more preferably>5。