JPS5939242B2 - surface coated tool parts - Google Patents

Description

Detailed Description of the Invention The present invention has a coating layer that has excellent toughness and abrasion resistance and has strong adhesion to tool parts, and is particularly suitable for use in cutting and wear-resistant applications. The present invention relates to surface-coated tool parts.

Conventionally, it is known that cutting and wear-resistant tool parts are generally manufactured from materials such as high-speed steel, die steel, and cemented carbide, and in order to further improve their properties, tungsten (W) ) and tungsten carbide (hereinafter referred to as wC) on the surface of the tool part by chemical vapor deposition. The coating layer in the conventional surface-coated tool parts mentioned above is often 5.
Since it is relatively thin, at less than μm, and its average crystal grain size is also less than 1 μm, it has excellent toughness and wear resistance.

゛However, in recent years, for the conventional surface-coated tool parts mentioned above,
There is a trend toward the necessity of grinding the coating layer to improve dimensional accuracy and re-grinding the coating layer to reuse tool parts. Specifically, the layer thickness is 5 to 10001 tm, preferably 5
There is a growing demand for surface-coated tool parts having coating layers of Ottm or higher.

However, in the conventional surface-coated tool parts having the above-mentioned relatively thin coating layer, when the coating layer is thickened to a layer thickness of 5 μm or more, the adhesion of the coating layer to the tool part decreases, and the coating layer In addition, it becomes impossible to suppress the average crystal grain size of the coating layer to 1 μm or less, and the toughness and wear resistance of the coating layer deteriorates, making it impossible to put it into practical use. This is the current situation.

Therefore, from the above-mentioned point of view, the present inventors proposed that one or two types of W and WC be used in surface-coated tool parts.
Even if the thickness of the coating layer made of seeds is increased to 5 to 1000 μm for the purpose of improving dimensional accuracy, accuracy, and reuse, the coating layer has strong adhesion to tool parts and has excellent toughness. As a result of conducting research to obtain a surface-coated tool part in which the coating layer has an average crystal grain size of 1 μm or less in order to ensure wear resistance, (a) from one or two of W and WC; If a titanium carbide layer with a thickness of 0.1 to 30 μm is interposed as an intermediate layer before forming a thick coating layer with a thickness of 5 to 1000 μm on the surface of the tool component, the attachment of the coating layer to the surface of the tool component will be improved. The adhesion becomes extremely strong.

(b) In a surface-coated tool component having a coating layer made of one or two of W and WC, one or two of fluorine and chlorine is added to the coating layer in 0.
When the content is 0.005 to 1 atomic %, preferably 0.1 to 0.5 atomic %, even if the thickness of the coating layer is as thick as 5 to 1000 μm, grain growth is suppressed and the average crystal grain size is 1 μm.
A coating layer having the following microstructure can be stably obtained, and as a result, the coating layer has excellent toughness and wear resistance.

The findings shown in (a) and (g) above were obtained.

This invention has been made based on the above findings, and the reason why the thickness of the titanium carbide layer as the intermediate layer and the content of fluorine and chlorine in the coating layer are limited as described above will be explained below. (a) Layer thickness of intermediate layer If the layer thickness is less than 0.1 μm, the desired effect of improving adhesion cannot be obtained when forming the above-mentioned coating layer on the surface of the tool component, while on the other hand, if the layer thickness exceeds 301 tm, Since titanium carbide itself has brittle properties, the toughness of surface-coated tool parts decreases, so the layer thickness is reduced to 0.
．． It was determined to be 1 to 30 μm.

(b) Content of fluorine and chlorine in the coating layer When the content is less than 0.005 at%, the thickness of the coating layer is 5 to 5%.
When the thickness increases to 10,001 tm, the desired effect of suppressing crystal grain growth cannot be obtained, and regions with coarse grain sizes of 1 μm or more appear, although in many cases only partially. In a coating layer containing such coarse crystal grains, if the layer thickness exceeds 10 μm, columnar crystals will be formed, making it impossible to ensure the desired toughness and wear resistance.

On the other hand, if the content exceeds 1 atom%, in most cases, a layered region of concentrated fluorine and/or chlorine will appear in the coating layer, and this layered region will be brittle, and the layered region will be A coating layer having a region has a low adhesion strength as a whole, and therefore it is impossible to secure the desired toughness and wear resistance, so its content is reduced to 0.
．． The content was determined to be 0.005 to 1 atomic %. Furthermore, in manufacturing the surface-coated tool component of the present invention, the titanium carbide layer as an intermediate layer can be formed by known chemical vapor deposition, physical vapor deposition, sputtering, etc.
Furthermore, a coating layer made of one or two of W and WC containing one or two of fluorine and chlorine is disclosed in Japanese Patent Application No. 53-59907 previously filed by the same applicant.
(Surface coated tool parts and manufacturing method thereof).

Next, the surface-coated tool component of the present invention will be explained using examples.

A tool part made of high-speed steel (SKH-4) is inserted into a reaction vessel and heat-treated under the conditions of to form a titanium carbide layer as an intermediate layer on the surface of the tool part. A surface-coated tool part of the present invention was manufactured by applying a heat treatment to form a chlorine-containing coating layer on the intermediate layer.

The resulting surface-coated tool part of the present invention has a layer thickness of 6 μm.
layer thickness 3 through an intermediate layer of titanium carbide of m
It had a coating layer made of tungsten carbide (mixture of W2C and WC) containing 0.1 atom % of chlorine with a diameter of 0 μm, and the average crystal grain size in the coating layer was 1 μm or less.

Furthermore, when the fracture surface of the surface-coated tool component of the present invention was observed, there were no cracks at all between the coating layer and the intermediate layer, and between the intermediate layer and the surface of the tool component, confirming that the adhesive force was high. .

In addition, for the purpose of comparison, we observed the fracture surface of a comparative surface-coated tool part in which a coating layer was directly formed on the surface of the tool part under the same conditions as in the above example without forming an intermediate layer of titanium carbide. It was observed that board-like cracks were partially present between the coating layer and the surface of the tool part.

Furthermore, for the purpose of comparison, the thickness of the titanium carbide layer as an intermediate layer was 40 μm, which was outside the range of the present invention, with the reaction temperature and reaction time being 1100° C. and 5 hours, respectively, among the heat treatment conditions. When the fracture surface of a comparative surface-coated tool part manufactured under the same conditions as in the above example was observed, a large amount of cracks were observed in the intermediate layer, and it is clear that this causes a decrease in toughness.

Next, regarding the above-mentioned surface-coated tool parts of the present invention, comparative surface-coated tool parts without an intermediate layer, and comparative surface-coated tool parts in which the thickness of the intermediate layer is higher than the range of the present invention, the work material: JIS -SNCM-8, Cutting speed: 30m/Min, Feed: 1.27m/Revl, Depth of cut: 2Tm. When a cutting test was conducted under the condition of cutting time: 10 m1n, the coating layer peeled off 2 minutes after the start of cutting in the comparison surface-coated tool part without an intermediate layer, and in the case of the other comparison surface-coated tool part. In this case, slight chipping occurred in the coating layer, resulting in a rough finished surface.

In contrast, the surface-coated tool parts of the present invention showed no peeling or chipping in the coating layer, and exhibited extremely excellent cutting performance. As mentioned above, in the surface-coated tool component of the present invention, by interposing the intermediate layer made of titanium carbide between the tool component surface and the coating layer, the thickness of the coating layer can be made extremely thick. By making the adhesion of the coating layer extremely strong and by containing either fluorine or chlorine, or both, in the coating layer, grain growth can be prevented even when the layer thickness becomes extremely thick. Since it is suppressed to maintain a fine crystal structure, it has extremely excellent toughness and wear resistance, and therefore has excellent performance especially when used for cutting and wear resistance. It shows itself.

Claims (1)

[Claims] 1 Layer thickness made of titanium carbide: 0.1 to 30 μm
Coating with a layer thickness: 5 to 1000 μm consisting of one or two of tungsten and tungsten carbide containing 0.005 to 1 atomic % of one or two of fluorine and chlorine through an intermediate layer of The intermediate layer strengthens the adhesion between the tool part and the coating layer, and the coating layer contains either or both of fluorine and chlorine. A surface-coated tool component characterized in that the average crystal grain size of the component is 1 μm or less to improve toughness and wear resistance.