JPH04183877A - Production of cutting tool made of surface coated tungsten carbide base cemented carbide formed with hard coating layer having excellent adhesive property - Google Patents

Abstract

PURPOSE:To produce the cutting tool which does not generate peeling, etc., under severe conditions by forming an Nb or NbC layer of a specific thickness and a TiC layer as a hard coating layer on a WC base cemented carbide base body by vapor deposition and subjecting these layers to a diffusion reaction by a specific heat treatment. CONSTITUTION:The Nb or NbC layer is formed by vapor deposition at 0.05 to 0.5mum thickness on the surface of the WC base cemented carbide base body. Further, the TiC layer is deposited by evaporation as the hard coating layer on this layer. These layers are then subjected to the heat treatment for holding for a prescribed period of time at 900 to 1300 deg.C in a nonoxidative atmosphere. The above-mentioned Nb or NbC layer and TiC layer are subjected to the diffusion reaction in this way and the hard diffused layer essentially composed of the extremely hard (Ti, NB) C is formed at least at the boundary part with the surface of the above-mentioned base body. Further, the hard coating layer consisting of single layer or double layers of TiC, TiN, TiCN, TiCNO, Al2O3, are formed by vapor deposition at need. The cutting tool made of the surface coated WC base cemented carbide which has the excellent adhesive property of the hard coating layer, is resistant to peeling and has a long life is obtd. in this way.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention applies a conventional chemical vapor deposition method (CVD method) and physical vapor deposition method (PVD method) to the surface of a tungsten carbide (hereinafter referred to as WC) cemented carbide substrate. ) A surface coating W having extremely excellent adhesion to the substrate surface of a hard coating layer formed by
The present invention relates to a method for manufacturing a cutting tool made of CC cemented carbide.

[Conventional technology]

Conventionally, as described in, for example, JP-A-55-154562 and JP-A-58-67861, Ti carbide has been deposited on the surface of a WCC cemented carbide substrate using a CVD method or a PVD method. , nitride, carbonitride, carbonitride, and aluminum oxide (hereinafter, Ti
c, TiN, TiCN.

TiCN0. A method of manufacturing a surface-coated WCC cemented carbide cutting tool by forming a hard coating layer consisting of a single layer or a multilayer of two or more of the following is well known.

[Problem to be solved by the invention]

On the other hand, in recent years, with the labor-saving and energy-saving cutting process, cutting speeds are not only increasing, but heavy cutting such as high feed and high depth of cut is often used, and as a result, cutting tools are subject to harsh conditions. However, conventional surface-coated WC manufactured by the above method
C) In cutting tools made of cemented carbide, the adhesion between the base and the hard coating layer is not sufficient, so the hard coating layer tends to peel under these harsh conditions, resulting in insufficient cutting performance. The current situation is that it does not show this.

[Means to solve the problem]

Therefore, from the above-mentioned viewpoint, the present inventors
As a result of conducting research to develop a surface-coated WCC cemented carbide cutting tool that has a further improved adhesion of the hard coating layer to the surface of the cemented carbide substrate, we found that the conventional CVD method was applied to the surface of the WCC cemented carbide substrate. First, the Nb layer or niobium carbide (hereinafter referred to as NbC) layer is coated with O, [1
A TiC-3 layer is formed by vapor deposition to a thickness of 5 to 0.5 μm, and a TiC-3= layer is further formed by vapor deposition as a hard coating layer. :900～
When heat treatment is carried out under the conditions of holding at 1300°C for a predetermined time, a diffusion reaction occurs between the Nb layer or NbC layer and the TiC layer, and extremely hard Ti and Nb particles are formed at least at the interface with the substrate surface. Composite carbide (hereinafter referred to as (T i, Nb
) A diffusion layer mainly consisting of C) is formed, and this hard diffusion layer has extremely good adhesion to the substrate surface and the above-mentioned hard coating layer. The research results showed that even when put into practical use under various conditions, the hard coating layer did not peel off and exhibited excellent cutting performance over an extremely long period of time.

This invention was made based on the above research results, and after forming an Nb layer or a NbC layer with a thickness of 0.05 to 0.5 μm on the surface of a WCC cemented carbide substrate, A TiC layer is deposited as a hard coating layer, and then heat treated in a non-oxidizing atmosphere at a temperature of 900 to 130°C for a predetermined period of time to bond the Nb layer or NbC layer to the TiC layer.
A diffusion reaction is caused between the iC layer and the (Ti,Nb)C layer at least at the interface with the substrate surface, and if necessary, Tic and TiN.

T i CN, T i CNO, and A I! 2
A hard coating layer consisting of one type of single layer or a multilayer of two or more types of 03 is formed by vapor deposition, thereby manufacturing a surface-coated WCC cemented carbide cutting tool in which the hard coating layer has excellent adhesion. This method is unique.

In addition, in the method of this invention, the thickness of the Nb layer or NbC layer is limited to 0.05 to 0.5 μm because if the thickness is less than 0.05 μm, excellent adhesion (Ti
, Nb)C is insufficiently formed, while its thickness exceeds 0.5 μm, the N6 layer or the NbC layer is replaced by (Ti
This is because it takes a long time to form a Nb)C layer, making it impractical for actual operation, and the heat treatment temperature was set at 900°C.
The reason why the temperature was set at ~1300°C is that if the temperature is less than 900°C, the diffusion reaction between the Nb layer or NbC layer and the TiC layer will not take place sufficiently, whereas if the temperature exceeds 1300°C,
This is based on the reason that a crystal grain coarsening phenomenon appears.

〔Example〕

Next, the method of the present invention will be specifically explained using examples.

The composition shown in Table 1 and all CIS standard SN
WCC cemented carbide substrates having the shape of MG432 are prepared, and NbCl5° TiC1, H, CH4, N, etc. are applied to the surfaces of these substrates as reactive gases using a normal CVD method.
, Co2. and A12C13. After forming an Nb layer or NbC layer with the thickness shown in Table 1 and then a TiC layer by appropriately combining these reaction gases, the layers were heat-treated under the conditions also shown in Table 1. to cause a diffusion reaction between the Nb layer or the NbC layer and the TiC layer, so that at least the interface with the substrate surface has a thickness (T i, mainly composed of Nbl C) as shown in Table 1. Methods 1 to 10 of the present invention are carried out by forming a hard diffusion layer and subsequently depositing a hard coating layer having the composition and thickness shown in Table 1 on the hard diffusion layer. Hard alloy cutting tools (hereinafter referred to as coated cutting tools) were manufactured.

Moreover, for the purpose of comparison, conventional methods 1 to 10 were performed under the same conditions except that the heat treatment was not performed, and coated cutting tools were similarly manufactured.

Next, regarding the various coated cutting tools obtained as a result, the following were conducted: Work material: SNCM439 (Hardness: HB270), Cutting speed: 130 m/min.

Feed: 0.7mm/"ev.

Depth of cut: 2mm.

Cutting time: 20 minutes, dry high advance cutting test under the conditions, and work material: Fe.
12 (hardness: HB140), cutting speed: 300m/
min.

Feed: 0.25mm/rev.

Table 2 Depth of cut: 2mm.

A dry high-speed cutting test was conducted under the conditions of cutting time = 20 minutes, and the flank wear width and rake face wear depth of the cutting edge were measured. The results of these measurements are shown in Table 2.

〔Effect of the invention〕

From the results shown in Table 2, it can be seen that the coated cutting tools manufactured by methods 1 to 10 of the present invention showed that despite high-feed cutting and high-speed cutting, which are severe cutting conditions, The adhesion is extremely strong due to the formation of a hard diffusion layer mainly composed of (Ti, Nb)C, so the hard coating layer does not peel off and exhibits excellent wear resistance. In all of the coated cutting tools manufactured by conventional methods 1 to 1O, peeling occurred on the cutting edge due to insufficient adhesion of the hard coating layer to the substrate surface.
It is clear that the service life is reached in a relatively short period of time.

As described above, according to the method of the present invention, the hard coating layer is formed on the WCC cemented carbide substrate due to the presence of the hard diffusion layer mainly composed of (Ti, Nb)C formed at least at the interface with the substrate surface. It is possible to manufacture cutting tools made of surface-coated WCC cemented carbide that are firmly bonded to the surface, and therefore, this surface-coated WCC cemented carbide cutting tool can be used under harsh conditions such as high-speed cutting and heavy cutting. Even when used for cutting, there is no occurrence of peeling on the cutting edge, and it exhibits excellent cutting performance over a long period of time, resulting in industrially useful effects.

Claims (2)

[Claims] (1) Nb on the surface of the tungsten carbide-based cemented carbide base
After forming the niobium carbide layer or niobium carbide layer with a thickness of 0.05 to 0.5 μm, a titanium carbide layer is further formed as a hard coating layer, and then this is heated in a non-oxidizing atmosphere at a temperature of 900 µm. Heat treatment is performed under the conditions of holding at ~1300°C for a predetermined time to cause a diffusion reaction between the Nb layer or the niobium carbide layer and the titanium carbide layer, thereby forming a composite carbide of Ti and Nb at least at the interface with the surface of the substrate. A method for manufacturing a cutting tool made of a surface-coated tungsten carbide-based cemented carbide, characterized in that a hard diffusion layer is mainly formed, and the hard coating layer has excellent adhesion. (2) Nb on the surface of the tungsten carbide-based cemented carbide base
After the niobium carbide layer or niobium carbide layer is deposited to a thickness of 0.05 to 0.5 μm, a titanium carbide layer is further deposited as a hard coating layer, and then in a non-oxidizing atmosphere at a temperature of: Heat treatment is performed under the conditions of holding at 900 to 1300° C. for a predetermined time to cause a diffusion reaction between the Nb layer or niobium carbide layer and the titanium carbide layer, thereby forming a composite carbide of Ti and Nb at least at the interface with the surface of the substrate. A hard diffusion layer mainly composed of Ti is formed, and then a single layer of one kind or two or more kinds of Ti carbides, nitrides, carbonitrides, carbonitrides, and aluminum oxides is formed. A method for producing a surface-coated tungsten carbide-based cemented carbide cutting tool, the hard coating layer having excellent adhesion, the method comprising forming a multi-layer hard coating layer.