coated cutting tools

Abstract

The present invention relates to a coated cutting tool comprising a substrate and a coating, wherein the coating comprises a nano-multilayer of alternating layers consisting of a first nanolayer of Ti1-xAlxN, 0.35≤x≤0.70 and a second nanolayer of Ti1-ySiyN, 0.05≤y≤0.25, and further comprises a layer of Ti1-z-vMezAlvN, 0≤z≤0.10, 0.35≤v≤0.70, wherein Me is one or more of Cr, Zr, or V, and there exists an innermost layer of the coating closest to the substrate, having a thickness of about 1 to about 35 nm and being Ti1-wSiwN, 0.05≤w≤0.25.

Description

Technology Field

[0001] The present invention relates to a coated cutting tool having a coating comprising a nano-multilayer of (Ti,Si)N and (Ti,Al)N. Background Technology

[0002] Nano-multilayer coatings are commonly used in the field of cutting tools for metal machining. In these coatings, at least two layers that differ in some aspect alternately form a coating of a stack of nanolayers.

[0003] Metal machining operations include, for example, turning, milling, and drilling.

[0004] To provide a long tool life, coated cutting tools, such as inserts, must have high resistance to different types of wear, for example, flank wear resistance, crater wear resistance, chipping resistance, and peeling resistance.

[0005] Different metalworking operations affect coated cutting tools in different ways. For example, turning is a continuous metalworking operation, whereas milling is inherently more discontinuous. In milling, thermal and mechanical loads will vary over time.

[0006] In order to provide cutting tools with superior characteristics compared to cutting tools currently available on the market, there is a continuous demand for coated cutting tools in which the coating exhibits superior properties in terms of flank wear resistance, crater wear resistance, edge line toughness, comb crack resistance, and peel resistance. If one or more of the aforementioned characteristics are improved, a longer tool life is provided.

[0007] The object of the present invention is to provide a coated cutting tool exhibiting at least high flank wear resistance.

[0008] definition

[0009] The term "average layer cycle thickness" refers to the average thickness of combination AB in a nano-multilayer coating of the first nanolayer A and the second nanolayer B of the nano-multilayer ABABA.. If the deposition process is known, the average layer cycle thickness can be calculated by dividing the total thickness of the nano-multilayer by the number of AB depositions (corresponding to the number of rotations when depositing the substrate in a rotational manner).

[0010] Alternatively, the calculation can be performed using TEM analysis of the cross-section of the nano-multilayer, which counts the number of continuous AB nanolayer combinations over a length of at least 200 nm and calculates the average value.

[0011] The term "average column width" in nano-multilayers refers to the average value of the crystallizer columns, or "grains," in the nano-multilayers. A length of at least 500 nm perpendicular to the growth direction of the layer is considered, and the column width is measured over this length at at least four different points of the nano-multilayer at a distance of 500 nm from the bottom interface of the nano-multilayer.

[0012] If the nano-multilayer has a total thickness of only 0.5 μm, the measurement sites are located just below the outer surface of the nano-multilayer. Suitable analysis methods include transmission electron microscopy (TEM).

[0013] The present invention

[0014] Surprisingly, coated cutting tools with high wear resistance, particularly high flank wear resistance, have now been provided.

[0015] The present invention relates to a coated cutting tool comprising a substrate and a coating, wherein the coating is Ti 1-x Al x A first nanolayer where N is 0.35≤x≤0.70, and Ti 1-y Si yIt comprises a nanomultilayer of alternating layers consisting of a second nanolayer having N and 0.05≤y≤0.25, wherein a sequence of one first nanolayer and one second nanolayer forms a layer periodicity, the average layer periodicity thickness in the nanomultilayer is ≤ 20 nm, and the thickness of the nanomultilayer is about 0.3 to about 4 μm, and the coating is below the nanomultilayer, having a thickness of about 0.3 to about 2 μm and Ti 1-z-v Me z Al v It includes a layer where N is 0≤z≤0.10 and 0.35≤v≤0.70, where Me is one or more of Cr, Zr, or V, and has a thickness of about 1 to about 35 nm closest to the substrate, and Ti 1-w Si w There is an innermost layer of the above coating where N is 0.05≤w≤0.25.

[0016] Here, Ti 1-z-v Me z Al v The N layer consists of nano-multilayers and Ti in the coating. 1-w Si w It should be understood as being located between the layers of N.

[0017] 1st nanolayer Ti 1-x Al x For N, suitably 0.45≤x≤0.67, preferably 0.55≤x≤0.65.

[0018] Second nanolayer Ti 1-y Si y For N, suitablely 0.10≤y≤0.20.

[0019] The average layer period thickness of the nano-multilayer is suitably 2 to 20, preferably 4 to 10 nm.

[0020] The thickness of the nano multilayer is suitably about 0.7 μm to about 2 μm.

[0021] Ti 1-z-v Me z Al vFor the N layer, suitably 0≤z≤0.05, preferably z=0.

[0022] Ti 1-z-v Me z Al v For the N layer, suitably 0.45≤v≤0.67, preferably 0.55≤v≤0.65.

[0023] When z=0, Ti 1-z-v Me z Al v There is a preferred embodiment in which the Ti-Al relationship in N is the same as the Ti-Al relationship in the first nanolayer of the nano multilayer.

[0024] Ti 1-z-v Me z Al v The thickness of the N layer is suitably about 0.7 μm to about 1.5 μm.

[0025] Ti 1-w Si w For the innermost layer of N, suitably 0.10≤w≤0.20.

[0026] Ti 1-w Si w The thickness of the innermost layer of N is suitably about 2 to about 20 nm, preferably about 3 to about 10 nm.

[0027] In one embodiment, the coating is the outermost layer Ti 1-u Si u It includes N, where u is 0.05 ≤ u ≤ 0.25, preferably 0.10 ≤ u ≤ 0.20, and the thickness is about 0.1 to about 1 μm, preferably about 0.2 to about 0.7 μm. In a preferred embodiment, Ti 1-u Si u The Ti-Si relationship within N is the same as the Ti-Si relationship of the second nanolayer of the nanomultilayer.

[0028] In a preferred embodiment, Ti 1-z-v Me z Al v N layer and Ti 1-w Si w The innermost layers of N are adjacent to each other.

[0029] The nano multilayer film can suitably be a HIPIMS deposited layer.

[0030] In a preferred embodiment, the coating is Ti 1-x Al x A first nanolayer where N is 0.55≤x≤0.65, and Ti 1-y Si y It comprises a nanomultilayer of alternating layers consisting of a second nanolayer having N and 0.10≤y≤0.20, wherein the average layer period thickness in the nanomultilayer is 2 to 20 nm and the thickness of the nanomultilayer is about 0.7 to about 2 μm, and the coating is, below the nanomultilayer, having a thickness of about 0.7 to about 1.5 μm and Ti 1-v ,Al v It includes a layer where N is 0.55≤v≤0.65, and has a thickness of about 3 to about 10 nm closest to the substrate, and Ti 1-w Si w There is an innermost layer of the above coating where N is 0.10≤w≤0.20.

[0031] The substrate of the coated cutting tool may be selected from the group of cemented carbide, cermet, ceramic, cubic boron nitride, and high-speed steel. In one embodiment, the substrate is a cemented carbide comprising 5 to 18 weight% of Co and 0 to 10 weight% of carbides, nitrides, or carbonitrides of Group 4 to Group 5 of the periodic table.

[0032] Other components such as Cr are possible in the cemented carbide substrate.

[0033] Coated cutting tools are, appropriately, cutting tool inserts, drills, or solid end mills for metalworking. Cutting tool inserts are, for example, turning inserts or milling inserts. Brief explanation of the drawing

[0034] FIG. 1 illustrates a schematic diagram of one embodiment of a cutting tool that is a milling insert. FIG. 2 is a schematic cross-sectional view of one embodiment of a coated cutting tool of the present invention, illustrating a coating comprising a substrate and different layers. Specific details for implementing the invention

[0035] FIG. 1 illustrates a schematic diagram of one embodiment of a cutting tool (1) having a rake face (2), a flank face (3), and a cutting edge (4). In this embodiment, the cutting tool (1) is a milling insert. FIG. 2 illustrates a schematic diagram of a cross-section of one embodiment of a coated cutting tool of the present invention having a substrate body (5) and a coating (6). The coating consists of a first (Ti,Si)N innermost layer (7), a subsequent (Ti,Al)N layer (8), and a nano multilayer (9) in which (Ti,Al)N nanolayers (10) and (Ti,Si)N nanolayers (11) alternate.

[0036] yes

[0037] Example 1 (The present invention):

[0038] As a WC-Co based substrate, a milling insert of the geometry SPHT120408 cutting tool and a flat insert (for easy analysis of the coating) were provided. The substrate had a composition of 8 wt% Co and the remainder WC.

[0039] Next, the coating was deposited using HIPIMS mode on an Oerlikon Balzers Ingenia instrument using S3p technology. An uncoated insert blank was mounted in the PVD chamber and rotated during the deposition of the coating.

[0040] A standard Ar etching process was performed to clean the surface of the substrate so that about 20 to 50 nm was removed from the top of the substrate.

[0041] First, composition Ti 0.85 Si 0.15 The innermost layer of (Ti,Si)N was deposited on a WC-Co-based substrate using three targets.

[0042] The deposition process was performed in HIPIMS mode using the following process parameters.

[0043] Innermost layer of (Ti,Si)N:

[0044] Target Material: Ti 0.85 Si 0.15 (3 targets)

[0045] Target size: Circular, diameter 160 mm

[0046] Thickness: 12 mm

[0047] Average power per target: 8 kW

[0048] Peak pulse power: 60 kW

[0049] Pulse-on time: 4.46 ms

[0050] Temperature: 500℃

[0051] Total pressure: 0.52 Pa (N2+Ar)

[0052] Argon pressure: 0.43 Pa

[0053] Bias potential: -40 V

[0054] Number of repeating pulses

[0055] Per cycle: 1

[0056] A layer thickness of about 5 nm was deposited.

[0057] Next, the composition is Ti 0.40 Al 0.60 An additional (Ti,Al)N layer was deposited using three targets.

[0058] The deposition process was executed in HIPIMS mode using the following process parameters.

[0059] (Ti,Al)N layer:

[0060] Target Material: Ti 0.40 Al 0.60 (3 targets)

[0061] Target size: Circular, diameter 160 mm

[0062] Thickness: 12 mm

[0063] Average power per target: 9 kW

[0064] Peak pulse power: 60 kW

[0065] Pulse-on time: 7.56 ms

[0066] Temperature: 500℃

[0067] Total pressure: 0.60 Pa (N2+Ar)

[0068] Argon pressure: 0.43 Pa

[0069] Bias potential: -40 V

[0070] Number of repeating pulses

[0071] Per cycle: 1

[0072] A layer thickness of about 1 μm was deposited.

[0073] Next, the (Ti,Al)N / (Ti,Si)N nanolayer is Ti 0.40 Al 0.60 and Ti 0.85 Si 0.15 Further deposition was performed using three targets having the composition. The deposition process was executed in HIPIMS mode using the following process parameters.

[0074] (Ti,Al)N / (Ti,Si)N nanolayer:

[0075] Target Material: Ti 0.40 Al 0.60 and Ti 0.85 Si 0.15

[0076] Target size: Circular, diameter 160 mm

[0077] thickness: 12 mm

[0078] Average power per target: Ti / Al 4.5 kW / / TiSi 4.0 kW

[0079] Peak pulse power: Ti / Al 45 kW / / TiSi 45 kW

[0080] Pulse-on time: Ti / Al 5.00 ms / / TiSi 4.46 ms

[0081] Temperature: 500℃

[0082] Total pressure: 0.58 Pa (N2+Ar)

[0083] Argon pressure: 0.43 Pa

[0084] Bias potential: -50 V

[0085] Number of repeating pulses

[0086] Per cycle: 1

[0087] A layer thickness of approximately 1 μm was deposited. The average layer period thickness was approximately 5 nm.

[0088] The manufactured coated cutting tool is referred to as Sample 1 (the present invention).

[0089] Example 2 (Reference)

[0090] A reference sample of the coated cutting tool was fabricated. The reference coated cutting tool is currently being used commercially in ISO-P milling.

[0091] Ti on WC-Co based cutting insert substrate using HIPIMS mode on a 6-flange INGENIA S3p (Oerlikon Balzers) machine 40 Al 60 An N layer was deposited.

[0092] The substrate had a composition of 12 wt% Co, 1.6 wt% (Ta,Nb)C, and the remainder WC, and the WC grain size dWC was approximately 0.8 μm. The geometry of the cutting insert was SPHT120408.

[0093] Circular Ti with a diameter of 160 mm 40 Al 60 Six targets were used. HIPIMS Ti with a thickness of approximately 2 µm. 40 Al 60 An N monolayer was deposited using the following deposition parameters.

[0094] Total pressure: 0.59 Pa

[0095] Ar pressure: 0.43 Pa (the remainder up to full pressure is filled with N2)

[0096] Bias DC voltage: -40V

[0097] Temperature: 430℃

[0098] Power supply: 60 kW

[0099] Average power per target: 9.04 kW

[0100] Pulse on-time: 7.56 μs

[0101] Frequency: 20 Hz

[0102] # Repeat: 1

[0103] After that, average composition Ti 36 Al 64 A wear-resistant (Ti,Al)N layer of approximately 1.8 μm containing N was deposited by HIPIMS. Six circular targets with a diameter of 160 mm, and three Ti 33 Al 67 Target and 3 Ti 40 Al 60 An N target was used. The following deposition parameters were used:

[0104] Total pressure: 0.64 Pa (7 min) 0.61 Pa (52 min)

[0105] Ar pressure: 0.43 Pa (the remainder up to the total pressure is filled with N2)

[0106] Bias DC voltage: -40V

[0107] Temperature: 430 ℃

[0108] Power supply: 60 kW

[0109] On-time: Ti33Al67: 2.00 ms, Ti40Al60: 2.53 ms

[0110] Average power per target: Ti33Al67: 7.2 kW, Ti40Al60: 9.0 kW

[0111] The coated cutting tool produced is called Sample 2 (see reference).

[0112] Example 3:

[0113] Cutting tests were conducted to determine the performance of the fabricated samples.

[0114] Sample 1 (the present invention) and Sample 2 (reference), which are milling inserts of type SPHT120408, were tested in a milling test, and flank wear was measured. The cutting conditions are summarized in Table 1. As the workpiece material, steel ISO-P, 42CrMo4 was used.

[0115] Cutting conditions:

[0116]

[0117] The wear value (averaged across the cutting edge) for a cutting length of 5800 mm is listed in Table 2.

[0118]

[0119] Sample 1 (the present invention) exhibits superior performance (less flank wear) compared to Sample 2 (see reference).

Claims

Claim 1 A coated cutting tool (1) comprising a substrate (5) and a coating (6), wherein the coating (6) is Ti 1-x Al x A first nanolayer (10) in which N is 0.35≤x≤0.70, and Ti 1-y Si y A nano multilayer (9) comprising alternating layers of a second nanolayer (11) having N and 0.05≤y≤0.25, wherein a sequence of one first nanolayer (10) and one second nanolayer (11) forms a layer period, wherein the average layer period thickness in the nano multilayer (9) is ≤ 20 nm, and the thickness of the nano multilayer (9) is about 0.3 to about 4 μm, and the coating (6) is below the nano multilayer (9), having a thickness of about 0.3 to about 2 μm and Ti 1-z-v Me z Al v It comprises a layer (8) in which N is 0≤z≤0.10, 0.35≤v≤0.70, and Me is one or more of Cr, Zr, or V, and has a thickness of about 1 to about 35 nm closest to the substrate (5), and Ti 1-w Si w A coated cutting tool (1) having an innermost layer (7) of the coating (6) such that N is 0.05≤w≤0.

25. Claim 2 In claim 1, the first nanolayer (10), Ti 1-x Al x A coated cutting tool (1) for which 0.45≤x≤0.67 applies to N. Claim 3 In claim 1 or 2, the second nanolayer (11), Ti 1-y Si y A coated cutting tool (1) for which 0.10≤y≤0.20 applies to N. Claim 4 A coated cutting tool (1) according to any one of claims 1 to 3, wherein the average layer period thickness of the nano-multilayer (9) is 2 to 20 nm. Claim 5 A coated cutting tool (1) according to any one of claims 1 to 4, wherein the thickness of the nano-multilayer (9) is about 0.7 to about 2 μm. Claim 6 In any one of paragraphs 1 to 5, Ti 1-z-v Me z Al v A coated cutting tool (1) for the layer (8) of N, wherein 0≤z≤0.05 and 0.45≤v≤0.

67. Claim 7 In any one of paragraphs 1 through 6, Ti 1-z-v Me z Al v A coated cutting tool (1) having a thickness of about 0.7 to about 1.5 μm of the layer (8) N. Claim 8 In any one of paragraphs 1 through 7, Ti 1-w Si w A coated cutting tool (1) having 0.10≤w≤0.20 for the innermost layer (7) of N. Claim 9 In any one of paragraphs 1 through 8, Ti 1-w Si w A coated cutting tool (1) having a thickness of about 3 to about 10 nm of the innermost layer (7) of N. Claim 10 In any one of paragraphs 1 through 9, Ti 1-u Si u A coated cutting tool (1) having an outermost layer of N, wherein u is 0.05≤u≤0.25, preferably 0.10≤u≤0.20, and the thickness of the outermost layer is about 0.1 to about 1 μm, preferably about 0.2 to about 0.7 μm. Claim 11 In any one of paragraphs 1 through 10, Ti 1-z-v Me z Al v The above layer (8) and Ti in N 1-w Si w N-coated cutting tool (1) in which the innermost layer (7) is adjacent to each other. Claim 12 In any one of claims 1 to 11, the substrate (5) of the coated cutting tool (1) is selected from the group of cemented carbide, cermet, ceramic, cubic boron nitride, and high-speed steel. Claim 13 In any one of claims 1 to 12, the coated cutting tool (1) is a coated cutting tool (1) which is a cutting tool insert, drill, or solid end-mill for metal machining.

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