JP2697185B2 - Surface-coated tungsten carbide based cemented carbide cutting tool members - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention has a small thermal strain generated during cutting between a substrate and a hard coating layer, and has a high adhesion of the hard coating layer to the substrate surface. Needless to say, even when used for continuous cutting, a cutting tool member made of a surface-coated tungsten carbide-based cemented carbide that exhibits excellent cutting performance over a long period of time without causing chipping or chipping of the cutting edge (hereinafter referred to as “the cutting tool member”). , Abbreviated as coated carbide cutting tool).

[Conventional technology]

Conventionally, carbides, nitrides, and carbonitrides (hereinafter, referred to as Ti, respectively) of a tungsten carbide (hereinafter referred to as WC) -based cemented carbide substrate are formed on a surface of a cemented carbide substrate by a chemical vapor deposition method (CVD method) or a physical vapor deposition method (PVD method). TiC, TiN, and TiCN), a hard coating layer consisting of one single layer or two or more layers.
Alternatively, a lower layer composed of a single layer or one or more layers of TiC, TiN, and TiCN, and titanium carbonate, titanium carbonitride, and aluminum oxide (hereinafter, respectively)
TiCO, TiCNO, and indicated by Al ₂ O ₃₎ to form a hard coating layer which is composed of one or the upper layer comprising a single layer or a multi layer of two or more types of an average layer thickness of 0.5~10μm of Coated carbide cutting tools are used for continuous cutting and interrupted cutting of steel and the like.

[Problems to be solved by the invention]

On the other hand, in recent years, there is a strong demand for labor saving and shortening of the cutting process, and along with this, there is a tendency that high speed cutting under more severe conditions and heavy cutting such as high feed and high cutting are forced. In the above-mentioned conventional coated carbide cutting tools, at present, chipping and chipping are liable to occur in cutting blades, especially in intermittent cutting under severe conditions, and only a relatively short service life is exhibited.

[Means for solving the problem]

In view of the above, the present inventors have developed a conventional coated super hard cutting tool in order to develop a coated super hard cutting tool which does not cause chipping or chipping even in intermittent cutting under particularly severe conditions. When the cause of chipping or chipping in the hard coating layer of the hard cutting tool was investigated, one of the reasons was that the thermal expansion coefficient between the hard coating layer and the substrate was significantly different. Has a coefficient of thermal expansion of 8.6 × 10 ^-6 /
℃, TiN of 9.8 × 10 ^-6 / ℃, and TiCN of 9.4 × 10 ^-6 / ℃
Whereas that of the WC-based cemented carbide substrate is 5 × 10 ^-6
/ ° C., and the second reason is that the poor adhesion of the hard coating layer to the substrate surface has a second cause, and in order to solve these problems, As a result of the study, it was found that one of Zr carbides, nitrides, and carbonitrides (hereinafter referred to as ZrC, ZrN, and ZrCN, respectively) was formed between the hard coating layer and the substrate as an undercoating layer. When the layer or two or more layers are interposed with a relatively thin layer thickness as compared with the hard coating layer, the base coating layer has a thermal expansion coefficient of 7.0 × 10 ⁻⁶ / ZrC constituting the same.
℃, ZrN of 7.9 × 10 ^-6 / ℃, and ZrCN of 7.6 × 10 ^-6 / ℃
As described above, because of having an intermediate coefficient of thermal expansion between the hard coating layer and the substrate, the heat distortion generated between the hard coating layer and the substrate is significantly reduced even by the high heat generated during cutting, and further, the base coating layer When a small amount of oxygen is contained as a solid solution in at least the layer in contact with the substrate surface, the adhesion of the undercoat layer to the substrate surface is remarkably improved, and as a result, the hard coating layer adheres to the substrate surface via the undercoat layer. The coated cemented carbide cutting tool, which aims to reduce the thermal strain between the substrate and the hard coating layer and to improve the adhesion of the hard coating layer to the substrate surface, is capable of high-speed cutting and high feed. In addition to continuous cutting under severe conditions such as heavy cutting such as high cutting and high cutting, especially when used for interrupted cutting, there is no breakage or chipping in the cutting, and excellent wear resistance is extremely long It was obtained a finding that over shown.

The present invention has been made based on the above findings, and comprises a single layer of one of ZrC, ZrN, and ZrCN or a multilayer of two or more of the above on a surface of a WC-based cemented carbide substrate, And at least the layer in contact with the substrate surface contains 10 ppm to 1% by weight of oxygen as a solid solution.
A hard coating layer composed of a single layer of TiC, TiN, and TiCN or a multi-layer of two or more layers, or one of TiC, TiN, and TiCN through a base coating layer of about 5 μm; Hard coating composed of a lower layer consisting of a single layer or two or more layers of the above and an upper layer consisting of a single layer of one or more of TiCO, TiCNO and Al ₂ O ₃ The coated carbide cutting tool is characterized by having a layer having an average layer thickness of 0.5 to 10 μm.

In the coated cemented carbide cutting tool of the present invention, the content of dissolved oxygen in the base coating layer is set to 10 ppm to 1% by weight because a desired adhesion improving effect cannot be obtained if the content is less than 10 ppm. On the other hand, if the content exceeds 1% by weight, fine zirconium oxide (ZrO ₂ ) is deposited, and the adhesion is sharply reduced. Average layer thickness of 0.1 ~
The reason why the thickness is set to 5 μm is that if the layer thickness is less than 0.1 μm, the desired thermal strain reduction effect cannot be obtained, while if the layer thickness exceeds 5 μm, the undercoat layer itself is relatively soft. The reason is that the wear resistance of the tool itself decreases, and the average thickness of the hard coating layer is also reduced.
The reason that the thickness is set to 0.5 to 10 μm is that if the layer thickness is less than 0.5 μm, the desired wear resistance cannot be secured, while the layer thickness is
If the thickness exceeds 10 μm, the hard coating layer is chipped or chipped.

〔Example〕

Next, the coated carbide cutting tool of the present invention will be specifically described with reference to examples.

As WC-based cemented carbide substrates, indexable inserts each having the composition shown in Table 1 and having a shape corresponding to JIS / SNG432 were prepared. Using a conventional chemical vapor deposition method on the surface of E, the undercoating layer and the hard coating layer were each coated with: (a) In the case of ZrC: temperature: 1210 ° C, pressure: 50 torr, reaction gas composition: 3% ZrCl ₄ − 5% CH ₄ -92% H ₂ , (b) For ZrN Temperature: 1110 ° C, Pressure: 50 torr, Reaction gas composition: 3% ZrCl ₄ -6% N ₂ -91% H ₂ , (a) In the case of ZrCN Temperature: 1200 ° C., Pressure: 50 torr, Reaction gas composition: 3% ZrCl ₄ -2% CH ₄ − _{3% N 2 -92% H 2} , (d) when temperature of the ZrC oxygen containing: 1210 ° C., pressure: 50 torr, the reaction gas _{composition: 3% ZrCl 4 -5% CH} 4 -0.05~3% CO- 89 ~
91.95% H ₂ , (e) In the case of oxygen-containing ZrN Temperature: 1110 ° C, Pressure: 50 torr, Reaction gas composition: 3% ZrCl ₄ -6% N ₂ -0.1-5% CO-86-9
0.9% H _2, (f) if the temperature of the ZrCN oxygen containing: 1200 ° C., Pressure: 50 torr, the reaction gas _{composition: 3% ZrCl 4 -2% CH} 4 -3% N 2 -0.1~5% C
O-87 to 91.9% H ₂ , (g) For TiC Temperature: 1030 ° C, Pressure: 100 torr, Reaction gas composition: 4% TiCl ₄ -5% CH ₄ -91% H ₂ , (h) TiN If temperature: 980 ° C., pressure: 100 torr, the reaction gas _{composition: 4% TiCl 4 -8% N} 2 -88% H 2, (i) TiCN case temperature of: 1000 ° C., pressure: 100 torr, the reaction gas Composition: 4% TiCl ₄ -3% CH ₄ -4% N ₂ -89% H ₂ , (j) For TiCO Temperature: 1000 ° C, Pressure: 100 torr, Reaction gas composition: 4% TiCl ₄ -6% CO-90% H ₂ , (k) For TiCNO Temperature: 1000 ° C, Pressure: 100 torr, Reaction gas composition: 4% TiCl ₄ -3% CO-3% N ₂ -90% H ₂ , (l) In the case of Al ₂ O ₃ Temperature: 1000 ° C., pressure: 100 torr, reaction gas composition: 3% AlCl ₃ -5% CO ₂ -92% H ₂ , (the above reaction gas composition indicates volume%) And the second
The coated carbide cutting tools 1 to 14 of the present invention and the comparative coated carbide cutting tools 1 to 14 were produced by forming a base coating layer and a hard coating layer having the compositions and average thicknesses shown in the table.

The comparative coated carbide cutting tools 1 to 7 are those in which the underlying coating layer does not contain oxygen as a solid solution, and the comparative coated carbide cutting tools 8 to 14 are those in which the underlying coating layer is not formed.

Then, for these various coated cemented carbide cutting tools, work material: SNCM439 (Hardness: H _B 260), Cutting speed: 140 m / min, feed Ri: 0.25 mm / edge Depth of cut: 2 mm, cutting time: 15min, A dry milling test was performed on the steel under the conditions described in (1), the flank wear width of the cutting edge was measured, and the condition of the cutting edge was also observed. The results are shown in Table 3.

〔The invention's effect〕

From the results shown in Table 3, it can be seen that the coated carbide cutting tools 1 to 14 of the present invention all show that the presence of the undercoat layer reduces the heat distortion generated during cutting between the substrate and the hard coating layer, Because the adhesion of the hard coating layer to the substrate has been improved by the oxygen content of the coating layer,
The cutting edge does not suffer from chipping or chipping even under intermittent cutting under severe conditions, and exhibits excellent wear resistance. The adhesion of the layers is not sufficient, and the comparative coated carbide cutting tools 8 to 14 have a large thermal strain in addition to the insufficient adhesion of the hard coating layer to the substrate. It is clear that chipping occurs and shows only a short service life.

As described above, the coated carbide cutting tool of the present invention exhibits excellent cutting performance not only in continuous cutting under severe conditions but also in intermittent cutting for a remarkably long period of time.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location C23C 16/36 C23C 16/36 (72) Inventor Son-ichi Takahashi 1-297 Kitabukurocho, Omiya City, Saitama Prefecture (72) Inventor Yoshikazu Okada 1-27-20 Nishishinagawa, Shinagawa-ku, Tokyo Mitsubishi Metal Corporation Tokyo Works (56) References JP-A-51-151706 (JP, A) JP-B-63-505 (JP, B2) JP-B-59-14544 (JP, B2) JP-B-57-29547 (JP, B2)

Claims (2)

(57) [Claims] 1. A tungsten carbide-based cemented carbide substrate comprising, on the surface thereof, a single layer or a multilayer of two or more of Zr carbides, nitrides, and carbonitrides, and at least Average layer thickness in which the contacting layer contains 10 ppm to 1% by weight of oxygen as a solid solution: through an undercoating layer of 0.1 to 5 μm, a single layer of one of carbides, nitrides and carbonitrides of Ti Average layer thickness consisting of two or more layers: 0.5 to 10 μm
A cutting tool member made of a surface-coated tungsten carbide-based cemented carbide formed by forming a hard coating layer. 2. A tungsten carbide-based cemented carbide substrate comprising a single layer or a multilayer of at least one of Zr carbides, nitrides, and carbonitrides on the surface of a tungsten carbide-based cemented carbide substrate. Average layer thickness in which the contacting layer contains 10 ppm to 1% by weight of oxygen as a solid solution: through an undercoating layer of 0.1 to 5 μm, a single layer of one of carbides, nitrides and carbonitrides of Ti Average layer thickness composed of a lower layer composed of two or more layers and an upper layer composed of a single layer of one of titanium carbonate, titanium carbonitride and aluminum oxide or two or more layers. A cutting tool member made of a surface-coated tungsten carbide-based cemented carbide formed with a hard coating layer of 0.5 to 10 μm.