Surface wrapping cutting tool having excellent defect resistance and stripping resistance of hard wrapping layer

Abstract

The invention provides a surface wrapping cutting tool giving plays to excellent defect resistance, stripping resistance and adhesive strength during a small-caliber low speed cutting or high speed heavy cutting process and having a heterogeneous extension interface of a hard wrapping layer. The surface wrapping cutting tool is characterized by wrapping to form a columnar crystal organization TiA1N layer on a WC hard substrate surface via a physical vapor deposition, and when the crystal particle interface length in which [0001]WC is parallel with [110] TiA1N and [10-10]WC is parallel with [001] TiA1N is XA, and the crystal particle interface length in which [0001]WC is parallel with [111] TiA1N and [11-20]WC is parallel with [110] TiA1N is XC, possessing the heterogeneous extension interface satisfying the relationship of 1>(XA+XC) / X>=0.3(wherein, the X represents the interface total length) on the WC hard substrate surface and the surface of the TiA1N layer.

Description

technical field [0001] The present invention relates to a surface-coated cutting tool (hereinafter referred to as a coated tool), which is formed on the surface of a cutting tool substrate made of WC-based cemented carbide by physical vapor deposition to form a hard coating layer comprising at least a TiAlN layer In the surface-coated cutting tool, by forming a heteroepitaxial interface between the surface of the tool substrate and the TiAlN layer, in the small-diameter low-speed cutting that is prone to deposition chipping or the high-speed heavy cutting that applies a high load to the blade, the hard The coating layer exhibits excellent chipping resistance and peeling resistance. Background technique [0002] In general, for the clad tool, there are known inserts that are detachably mounted on the front end of the turning tool in turning of various steels or cast irons, etc. Insert-type end mills that perform cutting in the same way as solid-type end mills, drills that pe...

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Problems solved by technology

[0008] For example, in the clad tool shown in the above-mentioned Patent Document 1, an epitaxial interface was formed between the tool substrate and the hard clad layer by chemical vapor deposition (CVD) to improve the adhesion of the hard clad layer, but When trying to form an epitaxial interface by chemical vapor deposition (CVD), since the epitaxial interface is essentially limited to the (0001) plane or (10-10) plane of the WC crystal grain, the higher-order WC crystal plane is exposed. On the surface of the ordinary tool substrate, it is far from sufficient to say that the area ratio of the epitaxial interface is sufficient, but a non-epitaxial interface with weak adhesion is widely formed. During heavy cutting, the weak interface becomes the starting point of film peeling, so that not only The peeling resistance is not as expected, and the substrate is exposed to high temperature (about 1000°C) during evaporation, so the η phase is formed in the matrix structure, the residual stress cannot be introduced, and cracks are easy to occur, so even if the adhesion is achieved improvement, it cannot be said that it can satisfy the cutting performance as a coated tool

[0009] In addition, in the conventional clad tool shown in the above-mentioned Patent Document 2, the (0001) plane of WC and the surface of TiN are formed by physical vapor deposition (PVD) method. The epitaxial interface where the (111) plane is parallel and the [11-20] orientation of WC is parallel to the [110] orientation of TiN can improve the crack resistance and peeling resistance of the hard coating layer during cutting under normal conditions. However, under stricter cutting conditions, such as high-speed heavy cutting of steel or cast iron with high heat generation and high load on the blade, the chipping resistance and peeling resistance of the hard coating layer are not good. Sufficient, so there is a problem of short tool life

In addition, the base material of the above-mentioned existing coated tools requires a special composition containing many plate-shaped WC particles grown on the (0001) plane, so it is actually difficult to apply to hard tools sold in the market without the growth of the (0001) plane. Ordinary tool substrates made of high-quality alloy powder, or small-diameter drills and other fine or complex-shaped tool substrates

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