JPH0929509A - Cutting tool made of surface-coated tungsten carbide grouped hard metal wherein hard coating layer has excellent interlayer adhesion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tool made of surface coated-hard metal wherein a hard coating layer has excellent interlayer adhesion. SOLUTION: An Al-Si grouped oxide layer made by causing Al2 O3 contain Si at a rate of 1 to 20% by weight is provided in place of Al2 O3 , the case of a cutting tool made of surface-coated hard metal comprizing a hard coating layer which is formed, over a surface of a hard metal base body, so as to have an average layer thickness of 3 to 30μm and composed of a Ti-compound layer constituting of a single layer of one kind or a plurality of layers of more than two kinds among TiC, TiN, TiCN, TiCO, TiNO, and TiCNO, and an Al2 O3 layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard coating layer having excellent interlaminar adhesion and therefore, even when used for cutting, for example, mild steel having a large cutting resistance, delamination of the hard coating layer occurs. The present invention relates to a surface-coated tungsten carbide-based cemented carbide cutting tool (hereinafter referred to as a coated carbide cutting tool) that exhibits excellent cutting performance over a long period of time without chipping (fine chipping) of the cutting edge. .

[0002]

2. Description of the Related Art Conventionally, as described in Japanese Patent Publication No. 57-1585 and Japanese Patent Publication No. 59-52703, for example, a homogeneous tungsten carbide based cemented carbide substrate,
A tungsten carbide-based cemented carbide substrate having a binder phase-enriched zone in the surface portion, that is, in the surface portion, in which the content of, for example, Co as a binder phase forming component is relatively high compared to the inside of the substrate (hereinafter, these are collectively referred to On the surface of the cemented carbide substrate), using a chemical vapor deposition method or a physical vapor deposition method, Ti carbide,
Nitride, carbonitride, carbon oxide, oxynitride, and oxycarbonitride (hereinafter, respectively TiC, TiN, TiCN, Ti
CO, TiNO, and TiCNO))
A hard coating layer composed of a Ti compound layer composed of one single layer or two or more multi-layers and an Al oxide (hereinafter referred to as Al ₂ O ₃ ) layer with an average layer thickness of ₃ to 30 μm. The coated cemented carbide cutting tool is used for turning and milling mainly of alloy steel and cast iron.

[0003]

On the other hand, in recent years, the FA of cutting equipment has been remarkably changed, and in combination with the demand for labor saving of cutting work, the cutting tool tends to be required to have general versatility with respect to a work material. In the above-mentioned conventional coated carbide cutting tool, there is no problem when it is used for cutting alloy steel or cast iron, but especially when used for cutting mild steel having high cutting resistance, especially Al ₂ O Insufficient adhesion of the Ti compound layer to the _three layers not only facilitates delamination between the Al ₂ O ₃ layer and the Ti compound layer, but also
The current situation is that chipping and the like easily occur on the cutting edge, and this leads to a relatively short service life.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above viewpoints, attention is paid to the above-mentioned conventional coated carbide cutting tool, and the Al ₂ O ₃ layer and Ti
As a result of research to improve the interlayer adhesion with the compound layer, the Al ₂ O ₃ layer constituting the hard coating layer of the conventional coated carbide cutting tool described above was replaced with Al ₂ O ₃ in an amount of 1 to 20.
When composed of an Al-Si-based oxide layer containing Si in a weight percentage, the Al-Si-based oxide layer also has excellent adhesion to the Ti compound layer that constitutes the hard coating layer, and Since the Al ₂ O ₃ layer has the properties of the Al ₂ O ₃ layer, the hard coating layer has excellent interlaminar adhesion and exhibits excellent cutting performance.

The present invention has been made based on the above-mentioned research results, and Ti is formed on the surface of a cemented carbide substrate.
C, TiN, TiCN, TiCO, TiNO, and T
A coated cemented carbide formed by forming a hard coating layer composed of a Ti compound layer composed of one type of iCNO or a multilayer of two or more types and an Al ₂ O ₃ layer with an average layer thickness of ₃ to 30 μm. In a cutting tool, Al ₂ O ₃ constituting the hard coating layer
Instead of a layer, Si is added to Al ₂ O ₃ at a ratio of 1 to 20 wt%.
By providing an Al-Si-based oxide layer containing Al, the adhesion between the Ti compound layer and the Al-Si-based oxide layer is improved, and thus delamination of the hard coating layer is prevented. It is characterized by

In the coated cemented carbide cutting tool of the present invention, the Al-Si-based oxide layer constituting the hard coating layer is formed by a chemical vapor deposition apparatus or a physical vapor deposition apparatus in a reaction gas composition: volume%, AlCl. ₃ : 1 to 20%, CO ₂ : 0.
_{5~30%, SiCl 4: 0.001~0.2%} , HCl if necessary: 1-20% and / or H ₂ S:
0.05 to 5%, H ₂ : remaining, reaction temperature: 850 to 10
It can be formed under the conditions of 50 ° C. and atmospheric pressure: 30 to 200 torr, and has a Si content ratio of 1 to 20.
The reason why the content is defined as wt% is that if the proportion is less than 1 wt%, the desired interlayer adhesion cannot be ensured, and if the proportion exceeds 20 wt%, the wear resistance decreases. Because. Further, Ti constituting the hard coating layer
The compound layer is formed by a chemical vapor deposition method and / or a physical vapor deposition method under normal conditions. However, when the first layer is a TiN layer, the Ti layer of the first layer is formed when forming the second and subsequent layers.
In some cases, the C component forming the cemented carbide substrate may diffuse and form a solid solution in the N layer. In this case, a part or the whole of the first layer is made of TiCN. Further, the average layer thickness of the hard coating layer is set to 3 to 30 μm, because when the average layer thickness is less than 3 μm, desired excellent wear resistance cannot be secured, while the average layer thickness is 30 μm. The reason for this is that if it exceeds the limit, chipping or chipping of the cutting edge is likely to occur. In this case, it is desirable that the Al—Si-based oxide layer has an average layer thickness of 0.1 to 15 μm.
Further, when the TiCN layer forming the Ti compound layer has a vertically elongated crystal structure described in, for example, Japanese Patent Laid-Open No. 6-8010, a cutting performance superior to that of a normal granular crystal structure is exhibited. become.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the coated carbide cutting tool of the present invention will be specifically described by way of Examples. As a raw material powder, a medium-grain WC powder having an average particle diameter of 3 μm, the same as 5 μm
Coarse-grained WC powder, 1.5 μm (Ti, W) C (weight ratio, the same below, TiC / WC = 30/70) powder, 1.2 μm (Ti, W) CN (TiC / TiN) / WC
= 24/20/56) powder, the same 1.3 μm (Ta, N
b) C (TaC / NbC = 90/10) powder and 1.2 μm Co powder were prepared.
And wet-mixed with a ball mill for 72 hours, dried, and then subjected to ISO • CNMG120408.
(For cemented carbide base bodies A to D) and the same SEEN42AFT
N1 (for cemented carbide substrate E) was press-molded into a powder compact having a shape determined, and the powder compact was vacuum-sintered under the conditions shown in Table 1 to manufacture cemented carbide substrates A to E, respectively. . Further, with respect to the cemented carbide base material B, 100 torr of CH
_{In a 4} gas atmosphere, hold at a temperature of 1400 ° C for 1 hour and then perform a carburizing treatment of slow cooling. After the carburizing treatment, carbon and Co adhering to the substrate surface are removed by acid and barrel polishing to a depth of 12 μm Maximum Co content at position: 1
A Co-rich zone showing 4.7 wt% and having a depth of 41 μm was formed on the surface of the substrate. In addition, the cemented carbide base A
And D, in the as-sintered state, show a maximum Co content of 9.4 wt% at a depth position of 15.5 μm from the surface and a Co-rich zone with a depth of 20 μm on the surface of the substrate. The remaining cemented carbide substrates C and E, which had been formed, did not have the formation of the Co-enriched zone and had a homogeneous structure throughout. Further, Table 1 shows that the cemented carbide substrates A to E
Of each sample (Rockwell hardness A scale).

Then, the surfaces of these cemented carbide substrates A to E were subjected to honing, using a conventional chemical vapor deposition apparatus, and under the conditions shown in Table 2 under the conditions shown in Table 2 and the compositions shown in Tables 3 to 5 By forming a hard coating layer having an average layer thickness, the coated carbide cutting tools 1 to 15 of the present invention and the conventional coated carbide cutting tools 1 to 15 were manufactured.

Next, the above-mentioned coated carbide cutting tool 1 of the present invention.
~ 13 and conventional coated carbide cutting tools 1 to 13,
Work Material: Mild Steel Round Bar, Cutting Speed: 290 m / min., Depth of Cut: 2.0 mm, Feed: 0.3 mm / rev., Cutting Time: 3
Continuous cutting test of mild steel under the condition of 0 minutes, and work material: square steel of mild steel, cutting speed: 270 m / min., Depth of cut: 2 mm, feed: 0.3 mm / rev., Cutting time: 40
The intermittent cutting test of mild steel was carried out under the conditions of, and the flank wear width of the cutting edge was measured in each cutting test. Further, regarding the coated carbide cutting tools 14 and 15 of the present invention and the coated carbide cutting tools 14 and 15 of the related art, the work material: square bar of mild steel, cutting speed: 280 m / min., Depth of cut: 2.5 mm, feed:
Milling of mild steel was performed under the conditions of 0.33 mm / blade and cutting time: 40 minutes, and the flank wear width of the cutting edge was measured in the same manner. The results of these measurements are shown in Tables 3-5.

[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, the coated cemented carbide cutting tools 1 to 15 of the present invention all have a delamination phenomenon in the hard coating layer despite the cutting of mild steel having high cutting resistance. While the cutting edge shows excellent wear resistance without chipping, the conventional coated carbide cutting tools 1 to 15 have insufficient adhesion between the Al ₂ O ₃ layer and the Ti compound layer in the hard coating layer. It is clear that the occurrence of delamination and chipping at the cutting edge is unavoidable in the cutting of mild steel because of the above, and as a result, the service life is reached in a relatively short time. As described above, in the coated cemented carbide cutting tool of the present invention, the hard coating layer is composed of the Ti compound layer and the Al-Si-based oxide layer having excellent adhesion to the Ti compound layer, and as a result, excellent interlayer adhesion is provided. And the Al--Si
Since the oxide system oxide layer has the same properties as the Al ₂ O ₃ layer in terms of cutting performance, excellent cutting performance can be achieved for a long time, not only when cutting alloy steel or cast iron, but also when cutting mild steel with high cutting resistance. It has industrially useful properties such as being exhibited over a long period of time.

Claims (1)

[Claims] 1. A Ti carbide, a nitride, a carbonitride on the surface of a tungsten carbide-based cemented carbide substrate which is wholly homogeneous, or a tungsten carbide-based cemented carbide substrate which has a binder phase enriched zone on the surface. A hard coating layer composed of a Ti compound layer and an Al oxide layer composed of a single layer of carbon oxide, a nitrogen oxide, and a multi-layer of two or more of carbon monoxide and 3
In a surface-coated tungsten carbide-based cemented carbide cutting tool formed with an average layer thickness of ˜30 μm, in place of the Al oxide layer forming the hard coating layer, Al is used.
Surface-coated tungsten carbide based cemented carbide having a hard coating layer having excellent interlayer adhesion, characterized in that an Al-Si-based oxide layer containing Si in an oxide content of 1 to 20% by weight is provided. Alloy cutting tool.