JP3282592B2 - Surface-coated cemented carbide cutting tool that demonstrates excellent wear resistance in high-speed cutting - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a titanium carbide nitride layer constituting a hard coating layer, which has a fine vertically-grown crystal structure, and is used for high-speed cutting of steel or cast iron, for example. The present invention relates to a cutting tool made of a surface-coated cemented carbide (hereinafter referred to as a coated cemented carbide tool) capable of exhibiting excellent wear resistance over a long period of time.

[0002]

2. Description of the Related Art Conventionally, a titanium carbide (hereinafter referred to as TiC) layer and a titanium nitride (hereinafter referred to as TiC) layer each having a granular crystal structure are generally provided on the surface of a tungsten carbide-based cemented carbide substrate (hereinafter referred to as a cemented carbide substrate). Hereinafter, also denoted by TiN) layer,
Titanium carbonitride (hereinafter referred to as TiCN) layer, titanium carbonate (hereinafter referred to as TiCO) layer, titanium oxynitride (hereinafter referred to as TiCO)
TiNO) layer and titanium carbonitride (hereinafter referred to as T
a Ti compound layer composed of one or more of iCNO layers, an α-type aluminum oxide (hereinafter referred to as α-Al ₂ O ₃ ) layer and / or a κ-type layer also having a granular crystal structure. Aluminum oxide (hereinafter referred to as κ-Al ₂
(Shown as O ₃ )).
Coated carbide tools made by chemical vapor deposition and / or physical vapor deposition with an average layer thickness of m are known, and the coated carbide tools are used for continuous or interrupted cutting of steel, cast iron, etc. Are known. Further, for example, Japanese Patent Laid-Open No. 7-3288
08, JP-A-6-8010, etc., in the hard coating layer of the coated cemented carbide tool, the TiCN formed at a high temperature of 1000 ° C. or higher using a normal chemical vapor deposition apparatus. The hard coating layer is formed by replacing the layer with a TiCN layer having a vertically grown crystal structure formed by performing chemical vapor deposition at a medium temperature range of 700 to 950 ° C. using a mixed gas containing an organic carbonitride as a reaction gas. There is also known a coated carbide tool which aims to improve the toughness of the steel and thereby significantly suppresses the occurrence of chipping or chipping (small chipping) of the cutting edge.

[0003]

On the other hand, with the recent high performance and high output of the cutting device, and in view of labor saving and energy saving of the cutting process, the cutting process tends to be faster. In the above-mentioned conventional coated carbide tool, if it is used for high-speed cutting, the progress of wear of the cutting edge is remarkably accelerated, and at present, the service life is reached in a relatively short time. This is not desirable from the viewpoint of making the device FA.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
In view of the above, in order to develop a coated carbide tool that exhibits excellent wear resistance even when performing continuous cutting or interrupted cutting of steel or cast iron at high speeds, in particular, improving the wear resistance of the hard coating layer As a result of conducting research, the constituent layers of the hard coating layer formed on the surface of the substrate were changed to a TiN layer having a granular crystal structure (hereinafter simply referred to as a TiN layer) and / or a TiCN layer as a first layer. Layer (hereinafter simply referred to as a TiCN layer), and a Ti layer having a vertically elongated crystal structure as a second layer.
As a third layer, a TiCO layer and / or a TiCNO layer (hereinafter simply referred to as a TiCO layer and a TiCN layer)
O layer) and an α-Al ₂ O ₃ layer and / or κ-Al ₂ layer each having a granular crystal structure.
O ₃ layer (hereinafter simply referred to as α-Al ₂ O ₃ layer and κ-Al ₂
O shows _three layers) and, if necessary, a TiN layer having a granular crystal structure as the fifth layer (hereinafter, simply indicated by TiN layer), the on identified, TiN of the first layer in the hard layer Layer and / or between the TiCN layer and the 1-TiCN layer, a titanium carbonitride having the same vertically-growing crystal structure as the 1-TiCN layer (hereinafter, referred to as 1-TiCNO)
With the intervening layer, the l-TiCNO layer can have a relatively fine structure, and thus the l-TiC layer formed on the l-TiCNO layer having the fine structure can be formed.
Since the N layer grows with the fine crystals of the l-TiCNO layer as nuclei, the N layer also has a fine crystal structure. Thus, the layer configuration of the hard coating layer is specified, and Coated cemented carbide tools in which the constituent l-TiCN layer is coated on the surface of a cemented carbide substrate with a hard coating layer having a fine-grained crystal structure include not only continuous cutting and interrupted cutting under ordinary conditions, but also The research results show that even when cutting is performed at high speed, excellent wear resistance will be exhibited over a long period of time.

The present invention has been made on the basis of the above-mentioned research results, wherein (a) a TiN layer having an average layer thickness of 0.1 to 2 μm and / or TiCN layer, (b) average layer thickness as second layer: 0.5
(C) Average layer thickness as a third layer: 2-20 μm l-TiCN layer, (d) Average layer thickness as a fourth layer: 0.05-2 μm TiCO layer and / or
Or a TiCNO layer, (e) a fifth layer having an average layer thickness:
0.2-15 μm α-Al ₂ O ₃ layer and / or κ
-Al ₂ O ₃ layer, optionally (f), the average layer thickness as the sixth layer: TiN layer of 0.1-2 .mu.m, more first layer to the sixth
A hard coated layer composed of layers is chemically and / or physically deposited with an overall average layer thickness of 3 to 30 μm. is there.

Next, the reason why the average layer thickness of the constituent layers of the hard coating layer and the overall average layer thickness of the coated carbide tool of the present invention are limited as described above will be described. (A) TiN layer and TiCN layer (first layer) Both the TiN layer and the TiCN layer have excellent adhesion to the surface of the superhard substrate, and prevent diffusion of components of the superhard substrate into the hard coating layer. Therefore, the hard coating layer has an effect of suppressing a decrease in wear resistance.
When the thickness is less than μm, the above effect is not sufficiently exhibited, while the above effect is sufficient with a layer thickness of up to 2 μm. Therefore, the layer thickness is set to 0.1 to 2 μm.

(B) 1-TiCNO Layer (Second Layer) As described above, the 1-TiCNO layer can be further refined in structure as compared with the 1-TiCN layer, and is thus formed thereon. The l-TiCN layer is refined by the above-mentioned l-T
Since it is possible to grow the fine crystal of the iCNO layer as a nucleus, there is an effect that the grown l-TiCN layer can have a fine vertical growth crystal structure. When the thickness is less than 0.5 μm, the effect of miniaturization on the l-TiCN layer is insufficient, while the thickness is 3 μm.
Even if it exceeds m, the above-mentioned action is saturated and no further miniaturization effect appears, so the layer thickness is set to 0.5 to 3 μm. It should be noted that l-TiCN having the above fine crystal structure
For the O layer, a normal chemical vapor deposition apparatus and a physical vapor deposition apparatus were used, and the reaction gas composition (in% by volume) —TiCl ₄ : 0.5 to 3
%, CO: 0.1~1%, CH 3 CN: 0.1~1%,
N ₂ : 5 to 30%, H ₂ : remaining, atmosphere temperature: 870 to 930 ° C., atmosphere pressure: 30 to 200 Torr.

(C) l-TiCN layer (third layer) The l-TiCN layer is an l-T layer having a lower layer fine crystal structure.
Due to the action of the iCNO layer, the vertically elongated crystal structure is refined, which, combined with the excellent toughness of the l-TiCN layer, further enhances the wear resistance of the hard coating layer, and provides excellent cutting performance even at high speed cutting for a long time. However, if the layer thickness is less than 2 μm, the above effect cannot be sufficiently exerted. On the other hand, if the layer thickness exceeds 20 μm, the cutting edge is liable to undergo thermoplastic deformation, which causes uneven wear. Therefore, the layer thickness was determined to be 2 to 20 μm.

(D) TiCO layer and TiCNO layer (fourth layer) In general, for example, the adhesion between the l-TiCN layer and the α-Al ₂ O ₃ layer is relatively low.
Although it causes the hard coating layer to peel off, the TiCO layer and Ti
Each of the CNO layers is an l-TiCN layer, α-Al ₂ O ₃
Layer and the κ-Al ₂ O ₃ layer,
This has the effect of improving the adhesion between the constituent layers of the hard coating layer. However, if the layer thickness is less than 0.05 μm, the desired effect of improving the adhesion cannot be obtained. Since chipping and chipping easily occur in the blade, the thickness of each layer is set to 0.05 to 2 μm.

(E) α-Al ₂ O ₃ layer and κ-Al ₂
O ₃ layer (fifth layer) Both the α-Al ₂ O ₃ layer and the κ-Al ₂ O ₃ layer have excellent oxidation resistance and thermal stability and high hardness. Together with the layer, it is indispensable for improving the wear resistance of the tool. However, if the layer thickness is less than 0.2 μm, the desired wear resistance cannot be secured. Since chipping and chipping easily occur, the layer thickness is set to 0.2 to 15 μm.

(E) TiN layer (sixth layer) Since the TiN layer itself has a golden color tone, it is necessary to make it easy to distinguish between before and after using a tool.
It is formed as needed and therefore 0.1
When the layer thickness is less than μm, the application of the color tone is insufficient. On the other hand, the layer thickness up to 2 μm is sufficient for the application of the color tone. Therefore, the layer thickness is set to 0.1 to 2 μm.

(F) Overall Average Thickness of Hard Coating Layer If the thickness is 3 μm, the desired excellent wear resistance cannot be ensured. On the other hand, if the thickness exceeds 30 μm,
Since chipping and chipping easily occur in the cutting blade, the overall average layer thickness was determined to be 3 to 30 μm.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the coated carbide tool of the present invention will be specifically described with reference to examples. Medium-sized WC powder having an average particle size of 3.1 μm, and 5.1 μm as the raw material powder
m of coarse WC powder, 1.4 μm of (Ti, W) C (the same in weight ratio, hereinafter, TiC / WC = 30/70) powder,
1.1 μm (Ti, W) CN (TiC / TiN / W
C = 24/20/56) powder, 1.0 μm (Ta,
Nb) C (TaC / NbC = 90/10) powder and Co powder of 1.2 μm were prepared, and these raw material powders were blended in the blending composition shown in Table 1, wet-mixed in a ball mill for 72 hours, and dried. After that, ISO ・ CNMG12040
8 (for carbide substrates A to D) and SEEN42AFTN
Press molded into a green compact having the shape defined in No. 1 (for the super hard substrate E), and the green compact was vacuum-sintered under the conditions shown in Table 1 to produce super hard substrates A to E, respectively. Further, with respect to the cemented carbide substrate C, 125 Torr CH
After holding at a temperature of 1400 ° C. for 50 minutes in a ₄ gas atmosphere, a slow carburizing treatment is performed, and after the treatment, carbon and Co adhering to the surface of the super hard substrate are removed by acid and barrel polishing to obtain 8 μm from the surface. Maximum Co content at the position: 15.
A Co-enriched zone of 6% by weight and a depth of 47 μm was formed on the surface of the substrate. The superhard substrates A and B were sintered as they were, and each surface had a maximum Co content of 9.3% by weight and a depth of 15 μm at a position of 13 μm from the surface.
Co-enriched zone (carbide substrate A) and 20 μm from the surface
m, maximum Co content: 13.0% by weight, depth: 2
A 5 μm Co-enriched zone (carbide substrate B) was formed, and the remaining cemented carbide substrates D and E had no such Co-enriched zone and had an overall homogeneous structure. Was. Table 1 shows the internal hardness (Rockwell hardness A scale) of each of the carbide substrates A to E.

Then, the surfaces of these super-hard substrates A to E were honed, and a conventional chemical vapor deposition apparatus was used to obtain them in Table 2 (the l-TiCNO layer and the l-TiC
Each of the N layers has a vertically elongated crystal structure, and the l-TiCN layer corresponds to a TiCN layer having a vertically elongated crystal structure described in JP-A-6-8010. Under the conditions described below, the hard coated layers having the compositions and target layer thicknesses shown in Tables 3 to 6 were formed to obtain the coated carbide tools 1 to 20 of the present invention, and l-TiCN.
Comparative coated carbide tool 1 under the same conditions except that no O layer was formed
-20 were each manufactured. The resulting coated carbide tools 1 to 20 and comparative coated carbide tools 1 to 20 obtained as a result were obtained.
As for No. 20, when the average layer thickness of the constituent layers of each hard coating layer was measured by a cross-sectional structure photograph with an optical microscope, the average thickness was substantially the same as the target layer thickness.

Next, the above-mentioned coated carbide tools 1 to 7 according to the present invention,
The present invention coated cemented carbide tools 11 to 17, Comparative coated carbide tools 11 to 17, and Comparative coated cemented carbide tools 1 to 7, Workpiece: JIS · SCM440 (hardness: H _B 210) round bar Cutting speed: 350 m / min. Infeed: 1.6 mm Feed: 0.31 mm / rev. Cutting time: 10 minutes, Dry high-speed continuous cutting test of alloy steel under the following conditions: Work material: JIS FC300 round bar, Cutting speed: 420 m / min. Infeed: 1.6 mm Feed: 0.31 mm / rev. Cutting Time: 10 min, dry high-speed continuous cutting test of cast iron in the conditions, Workpiece: JIS · SCM440 (hardness: H _B 210) square bar of cutting speed: 250 meters / min. Notch: 1.6 mm Feed: 0.22 mm / rev. The cutting speed was 5 minutes. A dry high-speed intermittent cutting test was performed on the alloy steel under the following conditions, and the flank wear width of the cutting edge was measured in each cutting test.

Further, the above-described coated carbide tools 8 to 10 of the present invention,
The present invention coated carbide tools 18-20 and Comparative coated cemented carbide tool 8-10 and Comparative coated carbide tools 18-20, are Workpiece: JIS · SCM440 (hardness: H _B 210) square bar of Usage conditions: Single blade attached to a 125 mm diameter cutter, Cutting speed: 310 m / min. , Depth of cut: 1.6 mm, feed: 0.18 mm / tooth, cutting time: 10 minutes, a dry high-speed milling (intermittent cutting) test of the alloy steel was performed, and the flank wear width of the cutting edge was measured. Tables 7 and 8 show the measurement results.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

[Table 3]

[0020]

[Table 4]

[0021]

[Table 5]

[0022]

[Table 6]

[0023]

[Table 7]

[0024]

[Table 8]

[0025]

As can be seen from the results shown in Tables 3 to 8, the 1-TiCNO layer having a fine crystal structure is present as the second layer of the hard coating layer, and the 1-TiCN layer formed thereon is also a fine crystal. The coated carbide tool of the present invention having a texture 1-20
Exhibits higher wear resistance compared to the comparative coated carbide tools 1-20 without the formation of the TiCNO layer in high-speed continuous cutting and high-speed interrupted cutting of steel and cast iron, all of which are subjected to severe cutting conditions. It is clear that As described above, the coated cemented carbide tool of the present invention has excellent wear resistance, as well as continuous cutting and interrupted cutting under ordinary conditions such as steel and cast iron, especially even when these cuttings are performed at high speed. And enables long-term cutting, which contributes to labor saving and energy saving in cutting.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23C 28/04 B23B 27/14 C23C 14/06 C23C 16/30

Claims (2)

(57) [Claims] 1. A titanium nitride layer and / or a titanium carbonitride layer having a granular crystal structure having an average layer thickness of 0.1 to 2 μm as a first layer of a hard coating layer on a surface of a tungsten carbide-based cemented carbide substrate, As the second layer, a vertically grown titanium carbonitride layer having an average layer thickness of 0.5 to 3 μm, and as the third layer, a titanium carbonitride layer having a vertically elongated crystal structure having an average layer thickness of 2 to 20 μm A titanium carbonate layer and / or a titanium carbonitride layer having a granular crystal structure having an average layer thickness of 0.05 to 2 μm as the fourth layer, and an average layer thickness of 0.2 to 15 μm as the fifth layer. An α-type and / or κ-type aluminum oxide layer having a granular crystal structure, and a hard coating layer composed of the first to fifth layers is 3 to 20.
A surface-coated cemented carbide cutting tool with excellent wear resistance in high-speed cutting, which is formed by chemical vapor deposition and / or physical vapor deposition with a total average layer thickness of μm. 2. A titanium nitride layer and / or titanium carbonitride layer having a granular crystal structure having an average layer thickness of 0.1 to 2 μm as a first layer of a hard coating layer on a surface of a tungsten carbide-based cemented carbide substrate, As the second layer, a vertically grown titanium carbonitride layer having an average layer thickness of 0.5 to 3 μm, and as the third layer, a titanium carbonitride layer having a vertically elongated crystal structure having an average layer thickness of 2 to 20 μm A titanium carbonate layer and / or a titanium carbonitride layer having a granular crystal structure having an average layer thickness of 0.05 to 2 μm as the fourth layer, and an average layer thickness of 0.2 to 15 μm as the fifth layer. An α-type and / or κ-type aluminum oxide layer having a granular crystal structure; a titanium nitride layer having a granular crystal structure having an average layer thickness of 0.1 to 2 μm as the sixth layer; and a first to sixth layers. Hard coating layer of 3 to 20 μm A surface-coated cemented carbide cutting tool that exhibits excellent wear resistance in high-speed cutting, made by chemical vapor deposition and / or physical vapor deposition with an average layer thickness.