JP3397054B2 - Surface-coated cemented carbide cutting tool with excellent chipping resistance - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has excellent chipping resistance. Therefore, for example, even when intermittent cutting of steel is performed at high speed, no chipping (fine chipping) occurs in the cutting edge, and excellent wear resistance. Surface-coated cemented carbide cutting tool that exerts long-term performance (hereinafter referred to as coated cemented carbide tool)
It is about.

[0002]

2. Description of the Related Art Conventionally, for example, an arc ion plating apparatus, which is one kind of physical vapor deposition apparatus shown in the schematic explanatory view of FIG.
In the state of being heated to a temperature of ° C, an arc discharge is generated between the anode electrode and the cathode electrode (evaporation source) in which a Ti-Al alloy having a predetermined composition is set, and at the same time, nitrogen gas as a reaction gas in the device, Or nitrogen gas and methane gas are introduced, while tungsten carbide (hereinafter referred to as WC)
A base made of a base cemented carbide or titanium carbonitride (hereinafter, referred to as TiCN) base cermet (hereinafter, these are collectively referred to as a cemented carbide base) is applied with a bias voltage of, for example, −120 V, On the surface of the cemented carbide substrate, as described in, for example, JP-A-62-56565, a composite nitride of Ti and Al [hereinafter (Ti, A
l) indicated by N] and complex carbonitride [hereinafter, (Ti, A
l) Shown as CN], or a single layer or multiple layers of hard coating layer composed of both of them can be vapor-deposited with an average layer thickness of 2 to 20 μm to produce a coated cemented carbide tool. Are known.

[0003]

On the other hand, in recent years, cutting machines have been remarkably improved in performance and output, and there is also a demand for labor saving and energy saving in cutting. Although there is a tendency, in the case of the above-mentioned conventional coated cemented carbide tool, although it shows excellent wear resistance in continuous cutting and interrupted cutting under normal cutting conditions, especially when interrupted cutting such as steel is performed at high speed. Is likely to cause chipping of the cutting edge due to insufficient toughness of (Ti, Al) N and (Ti, Al) CN that form the hard coating layer, and as a result, the service life is relatively short. is there.

[0004]

Therefore, the present inventors have
From the above-mentioned viewpoint, (Ti, Al) N and (Ti, which compose the hard coating layer of the conventional coated cemented carbide tool described above are used.
As a result of studying to improve the toughness of Al) CN, the composition formula: (Ti _a Al _b Mg _c ) N and the composition formula: (Ti _a Al _b Mg _c ) C _d N _1-d (however, in atomic ratio, a: 0.2 to 0.6, b: 0.1
~ 0.79, c: 0.01 to 0.3, a + b + c = 1,
d: 0.01 to 0.5), Ti, Al, and Mg
Compound nitride [hereinafter, represented by (Ti, Al, Mg) N]
And complex carbonitrides [hereinafter (Ti, Al, Mg) CN
Or a combination of two or more of the above], the resulting coated cemented carbide tool has the above (Ti, Al, Mg) N and (Ti, Al, Mg) C.
Since N has excellent toughness while maintaining excellent wear resistance, for example, not only continuous cutting of steel but also chipping of the cutting edge occurs even if intermittent cutting of this is performed at high speed. In other words, the research results that excellent wear resistance is exhibited over a long period of time were obtained.

The present invention was made on the basis of the above-mentioned research results.
A single-layer or multiple-layer hard coating layer deposited with an average layer thickness of μm was prepared by using a composition formula: (Ti _a Al _b Mg _c ) N, and a composition formula: (Ti _a Al _b Mg _c ) C _d N _{1-. d} , (however, in atomic ratio, a: 0.2 to 0.6, b: 0.1
~ 0.79, c: 0.01 to 0.3, a + b + c = 1,
d: 0.01 to 0.5), (Ti, Al, M
g) A coated cemented carbide tool having excellent chipping resistance, which is formed of either or both of N and (Ti, Al, Mg) CN, and is characterized. In the coated cemented carbide tool of the present invention, a titanium nitride (hereinafter referred to as TiN) layer having a golden color is used in an amount of 0.1 to 1 in order to facilitate the identification before and after use.
An average layer of μm is preferably deposited on the surface of the hard coating layer.

Next, the hard coating layer of the coated cemented carbide tool of the present invention comprises (Ti, Al, Mg) N and (T).
The reason why the composition ratio (atomic ratio) of i, Al, Mg) CN is limited as described above will be described. That is, the above (Ti, A
In (1, Mg) N and (Ti, Al, Mg) CN, the constituent components Ti and Al coexist in the state of contributing to the improvement of wear resistance. If it is less than 0.2 and less than Al: 0.1, the desired excellent wear resistance cannot be ensured. On the other hand, in the case of either Ti or Al, the ratio is Ti: 0.6 and Al: 0. If it exceeds 0.79, the toughness decreases and chipping is likely to occur at the cutting edge, so the ratio is Ti: 0.2 to 0.6, preferably 0.
3 to 0.5, Al: 0.1 to 0.79, preferably 0.
It was set to 3 to 0.7. In addition, the same constituent component Mg
Has the effect of improving toughness and thus preventing chipping of the cutting edge, but if the ratio is less than 0.01, the desired toughness improving effect cannot be obtained, while the ratio is 0.3. If it exceeds, the hardness of the layer itself is drastically reduced, and it becomes impossible to secure the excellent wear resistance provided by Ti and Al.
.About.0.3, preferably 0.05 to 0.2. Furthermore, since the C component in (Ti, Al, Mg) CN has the effect of improving hardness, (Ti, Al, Mg)
CN has a relatively high hardness as compared with the above (Ti, Al, Mg) N, but in this case, if the ratio of the C component is less than 0.01, a predetermined hardness improving effect cannot be obtained, while When the ratio exceeds 0.5, the toughness is rapidly reduced, so the ratio of the C component is set to 0.01 to 0.5, preferably 0.1 to 0.45. The average layer thickness of the hard coating layer is set to 2 to 20 μm because the desired wear resistance cannot be ensured when the layer thickness is less than 2 μm, and when the layer thickness exceeds 20 μm. This is because chipping easily occurs, and the average layer thickness of TiN vapor-deposited on the surface of the hard coating layer is set to 0.1 to 1 μm when the layer thickness is less than 0.1 μm. This is because a clear color cannot be imparted, while a desired golden color is sufficient with a layer thickness of up to 1 μm.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the coated cemented carbide tool of the present invention will be specifically described with reference to Examples. As the raw material powder, WC powder having an average particle diameter of 1 to 3 μm,
TiC powder, TaC powder, and Co powder were prepared, and these raw material powders were WC: 81% by weight% and TiC: 6
%, TaC: 4%, and Co: 9%, and after wet mixing for 72 hours in a ball mill and drying,
Press-molded into a green compact with a pressure of 1.5 ton / cm ² ,
This green compact is sintered in a vacuum at a temperature of 1400 ° C. for 1 hour, and after the sintering, a cutting edge portion is subjected to a honing process of R: 0.05 to obtain ISO standard / CNMG120408.
A WC-based cemented carbide substrate A having a tip shape was formed. In addition, as raw material powder, both are 0.5
TiCN having an average particle size of ~ 2 μm (TiC in weight ratio
/ TiN = 50/50) powder, Mo ₂ C powder, TiN powder, NbC powder, TaC powder, WC powder, Co powder, N
i powder and C powder were prepared, and these raw material powders were used in weight% of TiCN: 50%, Mo ₂ C: 16%, TiN:
8%, NbC: 6%, WC: 5%, TaC: 2%, C
o: 6%, Ni: 6%, and C: 1%, and the mixture was wet-mixed in a ball mill for 24 hours and dried.
The green compact was press-molded at a pressure of 1 ton / cm ² , and the green compact was heated in a nitrogen atmosphere of 10 torr at a temperature of 1540.
Sintered for 1 hour at ℃, after sintering, the cutting edge part is subjected to honing processing of R: 0.03 and ISO standard T
A cemented carbide substrate B made of TiCN-based cermet having a chip shape of NMG160408 was formed.

Next, these cemented carbide substrates A and B were respectively charged into the arc ion plating apparatus shown in FIG. 1, while Ti--Al-- having various component compositions as cathode electrodes (evaporation sources). Mg alloy and Ti-Al
Wearing the alloy, applied while holding the evacuating the apparatus to a vacuum of 1 × 10 ^{over 5} torr, in the apparatus with a heater and heated to 700 ° C., a bias voltage of over 120v to a cemented carbide substrate in this state Then, while introducing a nitrogen gas or a nitrogen gas and a methane gas as a reaction gas into the apparatus, an arc discharge is generated between the cathode electrode and the anode electrode, so that the respective surfaces of the cemented carbide substrates A and B are Table 1
~ 4 according to the present invention by forming a hard coating layer having the composition and average layer thickness shown in Fig.
And the conventional coated cemented carbide tools 1-4 were manufactured, respectively.

Of the various coated cemented carbide tools obtained as a result, for the coated cemented carbide tools 1 to 9 of the present invention and the conventional coated cemented carbide tools 1 and 2, the work material: the length of JIS SNCM439 A dry high-speed intermittent cutting test for alloy steel under the following conditions: 4 round bars with vertical grooves at equal intervals in the vertical direction, cutting speed: 300 m / min, feed: 0.3 mm / rev, depth of cut: 2 mm, cutting time: 10 minutes Further, regarding the coated cemented carbide tools 10 to 18 of the present invention and the conventional coated cemented carbide tools 3 and 4, the work material: JIS / S50C, four longitudinally equidistant round bars, cutting speed: 350 m / Min, feed: 0.3 mm / rev, depth of cut: 2 mm, cutting time: 10 minutes, a dry high-speed intermittent cutting test of carbon steel was performed, and the flank wear width of the cutting edge was measured in each cutting test. . The measurement results are shown in Tables 2 and 4.

[0010]

[Table 1]

[0011]

[Table 2]

[0012]

[Table 3]

[0013]

[Table 4]

[0014]

From the results shown in Tables 1 to 4, the coated cemented carbide tools 1 to 18 of the present invention all show excellent wear resistance in high-speed intermittent cutting of steel, and the wear condition of the cutting edge is also high. In contrast to the normal condition, the conventional coated cemented carbide tools 1 to 4 are chipped in the cutting edge in high-speed intermittent cutting of steel due to insufficient toughness of the hard coating layer, and thus chipping occurs in a relatively short time. It is clear that it will reach the end of its useful life. As described above, the coated cemented carbide tool of the present invention has the above (Ti, Al, Mg) N and (Ti, Al, M) constituting the hard coating layer.
g) Since CN has excellent toughness and high hardness, for example, not only high-speed continuous cutting of steel but also high-speed intermittent cutting of steel, which is a cutting process under more severe conditions, does not cause chipping of the cutting edge. It exhibits excellent wear resistance for a remarkably long period of time.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of an arc ion plating device.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Keiichi Sakurai Keiichi Sakurai 1511 Furumagi, Ishishita-cho, Yuki-gun, Ibaraki Mitsubishi Materials Corporation Tsukuba Works (56) Reference JP-A-8-199340 (JP, A) Hei 7-237011 (JP, A) JP Hei 5-337705 (JP, A) JP-B 5-67705 (JP, B2) JP-B 4-53642 (JP, B2) JP-B 7-65178 (JP , B2) Japanese Patent Publication No. 52-5406 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) C23C 14/00-14/58 C23C 16/00-16/56 B23B 27/00 -29/34 B23P 15/28

Claims (2)

(57) [Claims] 1. A surface of a tungsten carbide based cemented carbide substrate or a titanium carbonitride based cermet substrate is coated with 2 to 20 μm.
A single-layer or multiple-layer hard coating layer deposited with an average layer thickness of: (Ti _a Al _b Mg _c ) N, and a composition formula: (Ti _a Al _b Mg _c ) C _d N _1-d (However, in atomic ratio, a: 0.2 to 0.6, b: 0.1
~ 0.79, c: 0.01 to 0.3, a + b + c = 1,
d: 0.01 to 0.5), Ti, Al, and Mg
A surface-coated cemented carbide cutting tool having excellent chipping resistance, which is characterized by comprising either or both of the composite nitride and the composite carbonitride of. 2. The surface of a tungsten carbide-based cemented carbide substrate or titanium carbonitride-based cermet substrate has a thickness of 2 to 20 μm.
A single-layer or multiple-layer hard coating layer deposited with an average layer thickness of: (Ti _a Al _b Mg _c ) N, and a composition formula: (Ti _a Al _b Mg _c ) C _d N _1-d (However, in atomic ratio, a: 0.2 to 0.6, b: 0.1
~ 0.79, c: 0.01 to 0.3, a + b + c = 1,
d: 0.01 to 0.5), Ti, Al, and Mg
Of the composite nitride and the composite carbonitride, or both, and a titanium nitride layer having an average layer thickness of 0.1 to 1 μm is formed on the hard coating layer. A surface-coated cemented carbide cutting tool with excellent chipping resistance.