JPH0772350B2 - Manufacturing method of surface coated tungsten carbide based cemented carbide - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a surface-coated tungsten carbide-based cemented carbide in which the adhesion strength of a hard coating layer to a substrate surface is extremely high.

[Conventional technology]

Generally, the periodic table is formed on the surface of a substrate composed of WC-based cemented carbide containing tungsten carbide (hereinafter referred to as WC) as a main component and one or more of iron group metals as a binder phase forming component. 4a, 5a, and 6a metal carbides of
Forming a hard coating layer composed of a nitride of a group 5a metal, an oxide of a group 4a metal, and a solid solution of two or more kinds of these, and a single layer or two or more layers of aluminum oxide. It is well known that the surface-coated WC-based cemented carbide obtained as described above is also used as, for example, a cutting tool.

Usually, the above surface-coated WC-based cemented carbide is produced by forming the above-mentioned hard coating layer on the surface of the WC-based cemented carbide substrate by the chemical vapor deposition method, but forming the hard coating layer. Prior to this, chemical vapor deposition was carried out at a high temperature of about 1000 ° C., and the reaction gas used for this was considered to have a cleaning effect. Only the steps of washing the surface with an aqueous or neutral detergent are taken.

[Problems to be solved by the invention]

However, when this surface-coated WC-based cemented carbide is used as a cutting tool for high-load cutting with a large load, for example, because the adhesion strength of the hard-coated layer to the WC-based cemented carbide substrate is not sufficient, Peeling easily occurs in the hard coating layer, and the service life is reached in a relatively short time.

[Means for solving problems]

Therefore, the inventors of the present invention, from the above viewpoints, conducted research to produce a surface-coated WC-based cemented carbide with further improved adhesion strength of the hard coating layer to the WC-based cemented carbide substrate. As a result, caustic soda (hereinafter referred to as Na
Aqueous solution or potash (shown as KOH)
When the hard coating layer is formed by the chemical vapor deposition method in the state of being subjected to the surface treatment of immersion in an aqueous solution, the resulting hard coating layer becomes remarkably strongly adhered to the substrate surface,
For example, it has been found that, even when used under high load conditions such as high feed cutting, peeling is difficult and excellent performance can be exhibited over a long period of time.

This invention was made on the basis of the above findings, in the surface of the substrate composed of WC-based cemented carbide, when forming a hard coating layer using a normal chemical vapor deposition method, the hard coating layer of Prior to formation, aqueous NaOH solution or
Manufacture of surface-coated WC-based cemented carbide by improving the adhesion strength of the hard coating layer to the substrate surface by subjecting the hard coating layer to a surface treatment by dipping in a KOH aqueous solution. It is characterized by the law.

〔Example〕

Next, the method of the present invention will be specifically described by way of Examples.

As a WC-based cemented carbide substrate, use ISO30 P30 and prepare a SNMG432 slow-away chip with the same shape. After the surface treatment of the chips under the conditions shown in Table 1, use the usual chemistry. The methods 1 to 6 of the present invention were carried out by forming a hard coating layer composed of a single layer or multiple layers having the same composition and average layer thickness as shown in Table 1 by using a vapor deposition apparatus, and the surface coated WC group A hard alloy chip was manufactured.

Further, for comparison purposes, the method 1 of the present invention is used except that the surface treatment under the above conditions is not performed and the substrate surface is simply washed with a neutral detergent prior to the formation of the hard coating layer by chemical vapor deposition.
The conventional methods 1 to 3 were carried out under the same conditions as those in Nos. 3 to 3 to similarly produce surface-coated WC-based cemented carbide chips.

Then, regarding the surface-coated WC-based cemented carbide chip obtained as a result, the work material: SNCM-439 (H _B : 230), A high feed continuous cutting test of steel is performed under the conditions of cutting speed: 150 m / min, feed: 0.65 mm / rev., Depth of cut: 2 mm, cutting time: 5 min to measure the flank wear width of the chip cutting edge. Therefore, the abrasion resistance was evaluated, and the peeling resistance was evaluated by observing the peeling condition of the hard coating layer. The results are shown in Table 1.

〔The invention's effect〕

From the results shown in Table 1, in the surface-coated WC-based cemented carbide chips produced by the methods 1 to 6 of the present invention, there is almost no peeling of the hard coating layer, and it is very slight at all. Therefore, while showing excellent wear resistance, in the case of those manufactured by the conventional methods 1 to 3, peeling of the hard coating layer is large, which results in poor wear resistance. Is clear.

As described above, according to the method of the present invention, the surface coating WC-based cemented carbide having a very high adhesion strength of the hard coating layer to the surface of the WC-based cemented carbide substrate is formed on the substrate surface before the hard coating layer is formed. It can be manufactured by a simple operation of dipping surface treatment in NaOH aqueous solution or KOH aqueous solution, and when it is used as a cutting tool under high load conditions such as high feed cutting. It exhibits excellent performance over a very long period of time.

Claims (1)

[Claims] 1. A surface of a substrate composed of a tungsten carbide-based cemented carbide containing tungsten carbide as a main component and one or more of iron group metals as a binder phase forming component is provided on a surface of a periodic table 4a. , 5a and 6a group metal carbides, 4a and 5a group metal nitrides, 4a group metal oxides, solid solutions of two or more thereof, and a single layer or two of aluminum oxide When forming a hard coating layer consisting of two or more multi-layers by a normal chemical vapor deposition method, on the surface of the substrate, prior to the formation of the hard coating layer, the surface of immersion in a caustic soda aqueous solution or caustic potash aqueous solution A method for producing a surface-coated tungsten carbide-based cemented carbide, characterized in that the treatment enhances the adhesion of the hard coating layer to the surface of the substrate.