JPH11256332A - Cutting tool made of surface-coated cemented carbide excellent in chipping resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tool made of surface-coated cemented carbide excellent in chipping resistance. SOLUTION: This cutting tool made of surface-coated cemented carbide is the one in which the surface of a WC base cemented carbide base substrate is chemically vapor-deposited and/or physically vapor-deposited with a hard coating layer composed of one or two kinds of Ti compd. layers among a TiC layer, a TiN layer, a TiCN layer, a TiCO layer, a TiNO layer and a TiCNO layer or a hard coating layer in which the inside layer is composed of the Ti compd. layer, the intermediate layer is composed of an Al2 O3 layer and the outside layer is composed of the Ti compd. layer in the thickness of 3 to 20 μm. In this case, on the surface of the hard coating layer, as the outermost layer, a thinly filmed Al2 O3 layer having 0.01 to 0.1 μm thickness is formed by the vapor deposition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-coated cemented carbide that exhibits excellent chipping resistance, especially when used for high-speed cutting of a tough material such as austenitic stainless steel, mild steel, and high manganese steel. The present invention relates to a cutting tool (hereinafter, referred to as a coated carbide tool).

[0002]

2. Description of the Related Art Conventionally, generally, for example, Japanese Patent Application Laid-Open No. 6-315
No. 03, JP-A-6-316758, and
As described in Japanese Unexamined Patent Publication No. 7-216549,
Tungsten carbide-based cemented carbide substrate (hereinafter referred to as cemented carbide substrate)
U), a titanium carbide (hereinafter referred to as TiC) layer,
Titanium nitride (hereinafter also referred to as TiN) layer, carbonitride
Titanium (hereinafter referred to as TiCN) layer, titanium carbonate (hereinafter referred to as TiCN)
Bottom, indicated by TiCO) layer, titanium nitride oxide (hereinafter, TiN)
O) layer and titanium carbonitride (hereinafter referred to as TiCN).
O) or one or more of these layers
A hard coating layer composed of a compound layer, or
Compound layer and aluminum oxide (hereinafter, Al_Two O _Three Indicated by
Layer having an average layer thickness of 3 to 20 μm
Carbide by chemical vapor deposition and / or physical vapor deposition
Utensils are known.

[0003]

The above-mentioned conventional coated carbide tools are generally used for continuous cutting or interrupted cutting of steel, cast iron, etc., and these work materials are particularly used for austenitic stainless steel, mild steel, When a tough material such as manganese steel is used, the resistance applied to the cutting edge during cutting is relatively large, and therefore, the heat generated is also large. The Ti compound layer constituting the coating layer is relatively reactive,
Accordingly, when a high-speed cutting of the high toughness material accompanied by large heat generation is performed by using a coated carbide tool in which the outermost layer of the hard coating layer is formed of a Ti compound layer, a gap between the Ti compound layer and the high toughness material is obtained. A large reactive adhesive force is generated, and as a result, a phenomenon in which the cutting edge part involved in cutting is finely peeled, that is, chipping (micro chipping) occurs, and as a result, the service life is relatively short in service life. It is.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
In view of the above, to develop coated carbide tools that do not cause chipping on the cutting edge even when cutting high-toughness materials at high speed,
In particular, paying attention to the conventional coated carbide tool described above, as a result of conducting research, in a coated carbide tool in which the outermost layer of the hard coating layer is composed of a Ti compound layer, on the surface of the hard coating layer, as the outermost layer, When an Al ₂ O ₃ layer significantly thinned to a thickness of 0.01 to 0.1 μm is formed by vapor deposition, Al ₂ O ₃ itself has excellent oxidation resistance and thermal stability. Since the Al ₂ O ₃ layer is stable against large heat generation during cutting and has extremely low reactivity with high toughness materials, chipping does not occur on the cutting edge even at high speed cutting of high toughness materials. The research results show that excellent wear resistance will be exhibited over a long period of time.

The present invention has been made on the basis of the above research results, and a TiC layer and a T
Ti comprising one or more of an iN layer, a TiCN layer, a TiCO layer, a TiNO layer, and a TiCNO layer
A hard coating layer composed of a compound layer, or a hard coating layer composed of the Ti compound layer as the inner layer, the Al ₂ O ₃ layer as the intermediate layer, and the Ti compound layer as the outer layer, is 3 to 20.
In a coated carbide tool formed by chemical vapor deposition and / or physical vapor deposition with a thickness of μm, a thin Al ₂ O film having a thickness of 0.01 to 0.1 μm is formed as an outermost layer on the surface of the hard coating layer. It is characterized by coated carbide tools with excellent chipping resistance, formed by vapor deposition of _three layers.

[0006] In the coated carbide tool of the present invention,
Thinned Al formed as outermost layer _Two O_Three Layer thickness
The thickness is set to 0.01 to 0.1 μm because the thickness is 0.01 μm.
If it is less than μm, the desired effect of improving chipping resistance can be obtained.
On the other hand, if the thickness exceeds 0.1 μm,
In high-speed cutting, the layer itself peels off immediately after starting cutting.
The reason is that it becomes swelling. Also hard coating
The reason why the average layer thickness of the layer is 3 to 20 μm is that the layer thickness is 3 μm.
μm ensures the desired excellent wear resistance
On the other hand, if the layer thickness exceeds 20 μm,
This is because chipping is likely to occur.

[0007]

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 diameter of 2.8 μm, 4.9 μm as the raw material powder
m of coarse WC powder, 1.5 μm of (Ti, W) C (the same in weight ratio, hereinafter, TiC / WC = 30/70) powder,
1.2 μm (Ti, W) CN (TiC / TiN / W
C = 24/20/56) powder, 1.2 μm (Ta,
Nb) C (TaC / NbC = 90/10) powder and Co powder of 1.1 μm were prepared, and these raw material powders were blended in the composition shown in Table 1, wet-mixed in a ball mill for 72 hours, and dried. After that, ISO ・ CNMG12040
The compacts were press-molded into compacts having the shape specified in No. 8, and the compacts were vacuum-sintered under the conditions shown in Table 1 to produce super hard substrates A to E, respectively. Further, with respect to the super-hard substrate B, in a 100 Torr CH ₄ gas atmosphere,
Temperature: maintained at 1400 ° C. for 1 hour, then subjected to a slow cooling carburizing treatment, and after the treatment, carbon and Co adhering to the surface of the cemented carbide substrate were removed from the surface by acid and barrel polishing.
At a position of 1 μm, a Co-enriched zone having a maximum Co content of 15.9% by weight and a depth of 42 μm was formed on the surface of the substrate.
In addition, the above-mentioned super-hard substrates A and D are sintered as they are,
Maximum Co content at a position 17 μm from the surface on the surface:
A Co-enriched zone of 9.1% by weight and a depth of 23 μm is formed, and the remaining cemented carbide substrates C and E do not have the Co-enriched zone and have an overall homogeneous structure. Was something. Table 1 shows the internal hardness (Rockwell hardness A scale) of each of the carbide substrates A to E.

Next, the surfaces of these super hard substrates A to E
Then, with the honing applied, a normal chemical vapor deposition
Table 2 (Vertical growth crystal structure of TiCN layer in the table)
Is a vertically elongated crystal described in JP-A-6-8010.
Under the conditions shown in Tables 3 and 4,
And a Ti compound layer having the composition and thickness shown in FIG._Two O_Three
Layer and further thinned Al as the outermost layer_Two O_Three Composed of layers
Carbide coating of the present invention by forming a hard coating layer
Tools 1 to 10 and thinned Al as the outermost layer_Two O _Three Layers
Conventional coated carbide tools 1 to 1 under the same conditions except that they are not formed
0 were each produced.

Next, the coated carbide tools 1 to 10 according to the present invention will be described.
Workpiece: JIS SUS304 round bar, cutting speed: 250 m / min. , Depth of cut: 1.5 mm, feed: 0.3 mm / rev. , Cutting time: 10 minutes, Dry high-speed continuous cutting test of austenitic stainless steel under the following conditions: Work material: JIS SMn420 round bar, Cutting speed: 250 m / min. , Depth of cut: 1.5 mm, feed: 0.3 mm / rev. A dry high-speed continuous cutting test was performed on high manganese steel under the following conditions: cutting time: 10 minutes, and the flank wear width of the cutting edge was measured in each cutting test. Table 4 shows the results of these measurements.

[0010]

[Table 1]

[0011]

[Table 2]

[0012]

[Table 3]

[0013]

[Table 4]

[0014]

[Table 5]

[0015]

From the results shown in Tables 3 to 5, all of the coated carbide tools 1 to 10 of the present invention are austenitic, which is a high toughness material, due to the action of the thinned Al ₂ O ₃ layer formed as the outermost layer. The conventional coated carbide tools 1 to 1 show high wear resistance without chipping on the cutting edge even in high-speed cutting of stainless steel or high manganese steel, whereas the thinned Al ₂ O ₃ layer is not formed. In the case of No. 10, it is clear that chipping occurs in all of the cutting edges, and shows a relatively short service life. As described above, the coated cemented carbide tool of the present invention can provide not only continuous cutting and interrupted cutting under normal conditions such as steel and cast iron, but also excellent cutting performance especially for high-speed cutting of high toughness material for a long time. It works across.

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Kazuya Yanagita 1-297 Kitabukurocho, Omiya-shi, Saitama Pref.

Claims (2)

[Claims] 1. One of a titanium carbide layer, a titanium nitride layer, a titanium carbonitride layer, a titanium carbonate layer, a titanium oxynitride layer, and a titanium carbonitride oxide layer on a surface of a tungsten carbide-based cemented carbide substrate. Alternatively, in a surface-coated cemented carbide cutting tool obtained by chemical vapor deposition and / or physical vapor deposition of a hard coating layer composed of two or more Ti compound layers to a thickness of 3 to 20 μm, the surface of the hard coating layer In the outermost layer, 0.01 to
A surface-coated cemented carbide cutting tool with excellent chipping resistance, which is formed by depositing a thinned aluminum oxide layer having a thickness of 0.1 μm. 2. The surface of a tungsten carbide-based cemented carbide substrate, wherein the inner layer is selected from the group consisting of a titanium carbide layer, a titanium nitride layer, a titanium carbonitride layer, a titanium carbonate layer, a titanium oxynitride layer, and a titanium carbonitride oxide layer. A hard coating layer composed of one or two or more of the above, an aluminum oxide layer as an intermediate layer, and the above-mentioned Ti compound layer as an outer layer.
In a surface-coated cemented carbide cutting tool formed by chemical vapor deposition and / or physical vapor deposition with a thickness of m, 0.01 to
A surface-coated cemented carbide cutting tool with excellent chipping resistance, which is formed by depositing a thinned aluminum oxide layer having a thickness of 0.1 μm.