JPH10140353A - Cutting, tool made of surface coated cemented carbide in which hard coating layer has excellent wear resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tool made of surface coated cemented carbide in which a hard coating layer has excellent wear resistance. SOLUTION: This cutting tool made of cemented carbide is the one in which the surface of a WC base cemented carbide substrate is applied with a hard coating layer contg. an Al2 O3 layer with a κ type crystal structure, e.g. composed of one or >=two kinds of Ti compound layers among a TiC layer, a TiN layer, a TiCN layer, a TiCO layer, a TiNO layer and a TiCNO layer and an Al2 O3 layer with a κ type crystal structure at 2 to 20μm average layer thickness by chemical vapor deposition and/or physical vapor deposition. In this case, the crystal structure in the cutting edge ridgeline part of the Al2 O2 layer with κ type crystal structure composing the hard coating layer is regulated to an α type by laser irradiation heating transformation or electron beam irradiation heating transformation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a surface-coated cemented carbide in which a hard coating layer has excellent abrasion resistance, and therefore exhibits excellent cutting performance over a long period of time even for high-speed cutting of steel or cast iron, for example. The present invention relates to an alloy cutting tool (hereinafter, referred to as a coated carbide tool).

[0002]

2. Description of the Related Art Conventionally, generally, for example, Japanese Patent Publication No. 61-15 / 1986
As described in Japanese Patent Application Laid-Open No. 149 or JP-A-6-316758, a surface of a tungsten carbide-based cemented carbide substrate (hereinafter, referred to as a cemented carbide substrate) is coated with aluminum oxide (hereinafter, referred to as Al ₂ O ₃ ). Hard coating layer comprising a layer, for example T
i (hereinafter referred to as TiC) layer, nitride (hereinafter referred to as TiC)
Similarly, a layer represented by TiN), a carbonitride (hereinafter, represented by TiCN) layer, a carbonate (hereinafter, represented by TiCO) layer, a nitrided oxide (hereinafter, represented by TiNO) layer, and a carbonitride (hereinafter, represented by TiNO) A hard coating layer composed of one or two or more Ti compound layers (indicated by TiCNO) and an Al ₂ O ₃ layer having a kappa (κ) crystal structure.
Coated carbide tools made by chemical vapor deposition and / or physical vapor deposition with an average layer thickness of up to 20 μm are known, and the coated carbide tools are used for continuous or interrupted cutting of steel, cast iron, etc. Is also known.

[0003]

On the other hand, in recent years, the performance of cutting equipment has been remarkably improved, and there is a strong demand for labor saving. Accordingly, cutting work tends to be performed at a higher speed. In a hard tool, among the hard coating layers constituting the hard tool, the Al ₂ O ₃ layer having a κ-type crystal structure has insufficient wear resistance, and is used, for example, for high-speed cutting of steel or cast iron. At present, wear progresses quickly, and the service life is reached in a relatively short time.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above viewpoint, we focused on the hard coating layer of the coated carbide tool and conducted research to improve the wear resistance of the hard coating layer. As a result, the rake face and flank face of the cutting edge in the conventional coated carbide tool described above Irradiating a laser or an electron beam to a cutting edge ridge portion (hereinafter, simply referred to as a cutting edge ridge portion) where the
When the crystal structure of the Al ₂ O ₃ layer constituting the hard coating layer in this portion is transformed from κ type to alpha (α) type, the resulting coated cemented carbide tool has a particularly improved cutting edge ridge line portion, which is more resistant. Research results show that it has abrasion properties and exhibits excellent cutting performance over a long period of time even when performing continuous cutting and intermittent cutting under high-speed conditions as well as cutting under normal conditions. It was.

The present invention has been made on the basis of the above research results, and has a crystal structure of κ on the surface of a cemented carbide substrate.
A hard coating layer comprising an Al ₂ O ₃ layer of the type, for example a TiC layer,
Hard coating layer composed of one or more of Ti compound layers including TiN layer, TiCN layer, TiCO layer, TiNO layer, and TiCNO layer, and an Al ₂ O ₃ layer having a κ-type crystal structure Is formed with an average layer thickness of 2 to 20 μm, the crystal structure constituting the hard coating layer is the κ-type Al ₂ O ₃ layer, and the crystal structure of the cutting edge ridge portion is heated by laser irradiation. The present invention is characterized by a coated carbide tool having a hard coating layer having excellent abrasion resistance, which is an α-form of transformation or electron beam irradiation heating transformation.

[0006] In the coated carbide tool of the present invention,
When the average layer thickness of the hard coating layer is 2 to 20 μm, if the layer thickness is less than 2 μm, it is not possible to secure desired excellent wear resistance, while if the layer thickness exceeds 20 μm,
This is because the fracture resistance is reduced.
In addition, the transformation of the Al ₂ O ₃ layer from the κ-type crystal structure to the α-type crystal structure by laser irradiation heating or electron beam irradiation heating is performed by cutting the cutting edge ridge portion by 1000 by these heating means.
This is carried out by heating to １1400 ° C., preferably 1100 to 1300 ° C.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the coated carbide tool of the present invention will be specifically described with reference to examples. As the raw material powder, fine-grained WC powder having an average particle diameter of 1.5 μm;
C powder, 1.2 μm (Ti, W) CN (by weight ratio,
Hereinafter, the same, TiC / TiN / WC = 24/20/56)
Powder, 1.3 μm of (Ta, Nb) C (TaC / Nb)
C = 90/10) powder, 1 μm Cr 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.
Each of the compacts was press-formed into a green compact having the shape specified in Table 1, and the green compact was vacuum-sintered under the same conditions as shown in Table 1 to produce carbide substrates A to E, respectively. Table 1 shows the internal hardness (Rockwell hardness A scale) of each of the carbide substrates A to E. Next, these super-hard substrates A to
With the honing applied to the surface of E, a Ti compound layer and a κ-type Al ₂ having a composition and an average thickness shown in Table 3 were obtained under the conditions shown in Table 2 using a conventional chemical vapor deposition apparatus.
By forming an O ₃ layer, conventionally coated carbide tools 1 to 12
Was manufactured respectively.

Further, the following conditions are applied to the cutting edge ridges of the conventional coated carbide tools 1 to 12, ie, type: CO ₂ laser, output: 20 W, feed speed: 0.24 m / min, spot diameter. : 0.3 mm, Irradiation mode: Irradiation by two guns arranged on the extension of the rake face and flank, laser irradiation heating under the following conditions, or acceleration voltage: 40 kV, current: 100 mA, irradiation time: 1 sec, Irradiation mode: irradiates the beam pattern along the cutting edge ridge with high-speed deflection from two directions, the rake face side and the flank side, under the conditions of
By transforming the crystal structure of the l ₂ O ₃ layer from κ type to α type (confirmed by X-ray diffraction), the coated carbide tools 1 to 12 of the present invention can be obtained.
Was manufactured respectively.

Next, the coated carbide tools 1 to 12 according to the present invention will be described.
Work material: FC300 (hardness: HB180) round bar, Cutting speed: 450 m / min. , Depth of cut: 1.5 mm, feed: 0.45 mm / rev, dry continuous high-speed high-feed cutting test of cast iron, and work material: JIS SCM440 (hardness: HB220) round bar, cutting Speed: 400 m / min. Infeed: 1.5 mm. , Feed: 0.4mm / rev, A dry continuous high-speed high-feed cutting test of alloy steel was performed under the following conditions, and the flank wear width of the cutting edge was 0.3 in all cutting tests.
The cutting time to mm was measured. Table 4 shows the results of these measurements.

[0010]

[Table 1]

[0011]

[Table 2]

[0012]

[Table 3]

[0013]

[Table 4]

[0014]

From the results shown in Table 4, it can be seen that the coated carbide tools of the present invention obtained by partially transforming the crystal structure of the cutting edge ridge of the Al ₂ O ₃ layer in the hard coating layer from κ-type to α-type. 12
Is superior to conventional coated carbide tools 1 to 12 in which the entire Al ₂ O ₃ layer has a κ-type crystal structure, and has excellent wear resistance in high-speed high-feed cutting of cast iron and steel, which is a severe cutting condition. It is evident that it exhibits excellent cutting performance over a long period of time. As described above, in the coated cemented carbide tool of the present invention, the hard coating layer constituting the coated carbide tool exhibits excellent wear resistance, so that not only continuous cutting and interrupted cutting under ordinary conditions such as steel or cast iron, but also Even when used in severe conditions such as high-speed cutting, it exhibits excellent cutting performance over a long period of time, and therefore can sufficiently cope with the high performance of cutting equipment and save labor. Also contribute.

Claims (2)

[Claims] 1. A surface formed by chemical vapor deposition and / or physical vapor deposition of a hard coating layer including a copper-type aluminum oxide layer having a crystal structure with an average thickness of 2 to 20 μm on the surface of a tungsten carbide-based cemented carbide substrate. In the coated cemented carbide cutting tool, the crystal structure constituting the hard coating layer is formed by laser irradiation heating of the crystal structure at the cutting edge ridge portion where the rake face and flank of the cutting edge of the copper type aluminum oxide layer intersect. A cutting tool made of a surface-coated cemented carbide having a hard coating layer having excellent wear resistance, wherein the cutting tool is of an alpha type of transformation or electron beam irradiation heating transformation. 2. A Ti compound layer comprising a Ti carbide layer, a nitride layer, a carbonitride layer, a carbonate layer, a carbonitride layer, and a carbonitride layer on a surface of a tungsten carbide-based cemented carbide substrate. Surface coating obtained by chemical vapor deposition and / or physical vapor deposition of a hard coating layer composed of one or more of the above and a copper-type aluminum oxide layer with an average layer thickness of 2 to 20 μm. In a hard alloy cutting tool, the crystal structure constituting the hard coating layer is the crystal structure of the cutting edge ridge portion where the rake face and flank of the cutting edge of the copper-type aluminum oxide layer intersect, laser irradiation heating transformation or A cutting tool made of a surface-coated cemented carbide having excellent wear resistance, characterized in that the hard coating layer is of an alpha type of electron beam irradiation heating transformation.