JPH10251832A - Cutting tool made of surface-coated cemented carbide excellent in wear resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tool made of surface-coated cemented carbide excellent in wear resistance and showing excellent cuttability over a long period. SOLUTION: This cutting tool made of surface-coated cemented carbide is composed by applying the surface of a carbide tool substrate composed of WC base cemented carbide or TiCN base cermet with a heated and oxidized layer of a vapor deposited hard layer composed of one kind of single layer or two kinds of plural layers of (Ti, Al, M) N and (Ti, Al, M) CN expressed by the compositional formula of (Tia Alb Mc ) N and the compositional formula of (Tia Alb Mc ) Cd N1-d (where, by atomic ratio, a is 0.2 to 0.6, b is 0.1 to 0.79, c is 0.01 to 0.3, a+b+c+d=1 and d is 0.01 to 0.5 are satisfied, and M denotes any one kind among Mg, Ca, Sr and Si). Then, the composing layer of this heated and oxidized layer is composed of the one in which, on the base composed of (Ti, Al, M) NO or (Ti, Al, M) CNO, a hard coating layer having a structure in which fine Ti oxide, Al oxide and M oxide are dispersed and distributed is formed by the average layer thickness of 0.5 to 15μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting tool made of a surface-coated cemented carbide which has excellent wear resistance and therefore exhibits excellent cutting performance over a long period of time, for example, in continuous cutting and interrupted cutting of steel. Hereinafter, referred to as a coated carbide cutting tool).

[0002]

2. Description of the Related Art Conventionally, for example, an arc ion plating apparatus, which is a kind of physical vapor deposition apparatus schematically shown in FIG.
In the state heated to a temperature of ° C., an arc discharge is generated between the anode electrode and a cathode electrode (evaporation source) on which a Ti-Al alloy having a predetermined composition is set, and at the same time, a nitrogen gas as a reaction gas and Alternatively, nitrogen gas and methane gas are introduced, while tungsten carbide (hereinafter referred to as WC)
A tool base made of a base cemented carbide or a titanium cermet (hereinafter, referred to as TiCN) base cermet (hereinafter, these are collectively referred to as a cemented carbide tool base) are applied under a condition that a bias voltage of -120 V is applied, for example. On the surface of the cemented carbide tool substrate, a composite nitride of Ti and Al [hereinafter, referred to as (Ti, A), as described in, for example, JP-A-62-56565.
l) Indicated by N] and composite carbonitride [hereinafter, (Ti, A
l) Indicated by CN], a hard coating layer composed of a deposited hard layer composed of one kind of single layer or two kinds of multiple layers is 0.5 to
It is known to produce coated carbide cutting tools by forming with an average layer thickness of 15 μm.

[0003]

On the other hand, in recent years, FA and speed of cutting have been remarkable, and there is also a demand for labor saving and energy saving of cutting. As a result, the life of cutting tools has been extended. However, in the case of the above-mentioned conventional coated carbide cutting tool, the hard coating layers constituting it, ie, (Ti, Al) N and (T
The deposited hard layer composed of (i, Al) CN shows good chipping resistance (a property that a micro chip is hardly generated in a cutting edge), but has a short wear life and thus has a short service life due to insufficient wear resistance. is the current situation.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above viewpoint, (Ti, Al) N and (Ti, Al) constituting the hard coating layer of the conventional coated carbide cutting tool described above.
Al) focused on deposition hard layer consisting of CN, results of research to achieve this improve wear resistance, the deposited hard layers, the composition _{formula: (Ti a Al b M c} ) N, and the composition formula: _{(Ti a Al b M c)} C d N 1-d, ( provided that an atomic ratio, a: 0.2~0.6, b: 0.1
~ 0.79, c: 0.01 ~ 0.3, a + b + c = 1,
d: 0.01 to 0.5, M is Mg, Ca, S
r, and any one of Si), and a composite nitride and a composite carbonitride of Ti, Al, and M [hereinafter, (Ti, Al, M) N and (Ti,
Al, M) CN], and a single layer or two or more layers of the same, and then, in an oxidizing atmosphere under reduced pressure or pressure, in the range of 300 to 1000 ° C. After holding at a predetermined temperature for a predetermined time and performing cooling heat oxidation treatment, the coated hard layer made of (Ti, Al, M) N and (Ti, Al, M) CN in the coated carbide cutting tool becomes Complex nitride oxide of Ti, Al and M [hereinafter, (Ti,
Al, M) NO] and complex carbonitrides [hereinafter, referred to as
(Shown by (Ti, Al, M) CNO]) on a substrate consisting of a heated oxide layer having a structure in which fine Ti oxide, Al oxide and M oxide are dispersed and distributed. Research results have shown that coated carbide cutting tools comprising an oxide layer exhibit excellent wear resistance in continuous and intermittent cutting and exhibit excellent cutting performance over a long period of time.

[0005] This invention was made based on the above findings, the surface of the cemented carbide tool substrate, the composition _{formula: (Ti a Al b M c} ) N, and the composition formula: (Ti _a Al _b M _c ) C _d N _1-d , where a: 0.2 to 0.6, b: 0.1
~ 0.79, c: 0.01 ~ 0.3, a + b + c = 1,
d: 0.01 to 0.5, M is Mg, Ca, S
(Ti, Al, M) N and (Ti, Al, M) C represented by
N is composed of a heat-oxidized layer of a vapor-deposited hard layer composed of one kind of single layer or two or more kinds of N, and the constituent layer of this heat-oxidized layer is (Ti, Al, M) NO or (Ti, Al). , M)
A hard coating layer having a structure in which fine Ti oxide, Al oxide and M oxide are dispersed and distributed on a CNO substrate,
The present invention is characterized by a coated carbide cutting tool having excellent wear resistance and formed with an average layer thickness of 0.5 to 15 μm.

Next, (Ti, Al, M) N and (Ti, M) applied to the hard coating layer of the coated carbide cutting tool of the present invention.
The reason why the composition ratio (atomic ratio) of (Al, M) CN is limited as described above will be described. That is, (Ti, Al,
In (M) N and (Ti, Al, M) CN, the constituent components Ti and Al coexist and have an effect of contributing to the improvement of the wear resistance. If the ratio is less than 2 and Al: less than 0.1, the desired excellent wear resistance cannot be ensured. On the other hand, in the case of either Ti or Al, the proportion is Ti:
When the ratio exceeds 0.6 and Al: 0.79, the toughness decreases,
Since chipping is likely to occur on the cutting edge, the ratio is Ti: 0.2 to 0.6, preferably 0.3 to 0.5,
Al: 0.1 to 0.79, preferably 0.3 to 0.7. Further, M, which is also a component, has an effect of improving toughness and preventing chipping from occurring on the cutting edge, but if the ratio is less than 0.01, a desired effect of improving toughness cannot be obtained. On the other hand, if the ratio exceeds 0.3, the hardness of the layer itself sharply decreases, and it becomes impossible to secure the excellent wear resistance provided by Ti and Al. 0.3, desirably 0.05 to 0.2. Further, (Ti, A
Since the C component in (1, M) CN has an effect of improving the hardness, (Ti, Al, M) CN has the function of (Ti,
Al, M) N has a relatively high hardness as compared with N. In this case, if the proportion of the C component is less than 0.01, a predetermined hardness improving effect cannot be obtained. If it exceeds, the toughness rapidly decreases, so the ratio of the C component is set to 0.01 to 0.5, preferably 0.1 to 0.45.

The average thickness of the heat-oxidized layer constituting the hard coating layer of the coated carbide cutting tool of the present invention is 0.5 to 15 mm.
If the layer thickness is less than 0.5 μm, the desired wear resistance cannot be secured, while the layer thickness is 15 μm.
If the thickness exceeds μm, chipping easily occurs on the cutting edge. Further, in the coated carbide cutting tool of the present invention, in order to facilitate identification before and after use, titanium nitride having a golden color (hereinafter referred to as TiN) is used.
It is advisable to deposit a layer on the surface of the heat-oxidized layer with an average layer thickness of 0.1 to 1 μm. This is because the layer thickness is 0.1
If it is less than μm, a clear golden color cannot be imparted, whereas the desired golden color is due to the fact that a layer thickness of up to 1 μm is sufficient.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the coated carbide cutting tool of the present invention will be specifically described with reference to examples. WC powder having an average particle diameter of 1 to 3 μm,
TiC powder, ZrC powder, VC powder, TaC powder, Nb
A C powder, a Cr ₃ C ₂ powder, a TiN powder, a TaN powder, and a Co powder were prepared, and these raw material powders were blended in the composition shown in Table 1, wet-mixed in a ball mill for 72 hours, and dried. It is pressed into a green compact at a pressure of 1.5 ton / cm ² , and the green compact is heated in a vacuum at a temperature of 1400.
Sintering under the condition of holding at 1 ° C. for 1 hour.
Carbide tool bases A1 to A8 made of a WC-based cemented carbide having a chip shape of PGA120408 were formed. Further, as raw material powders, TiCN (TiC / TiN = 50/50 by weight ratio) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder each having an average particle diameter of 0.5 to 2 μm , Co powder, and Ni powder were prepared, and these raw material powders were blended in the blending composition shown in Table 2, wet-mixed in a ball mill for 24 hours, dried, and dried.
/ Cm ^{2 at} a pressure of 1 cm / cm ² , and sintering the compact in a nitrogen atmosphere of 10 torr for 1 hour at a temperature of 1540 ° C. After sintering, R: 0.0
3 Honing process, ISO standard, CNMG12
Carbide tool bases B1 to B6 made of TiCN-based cermet having a chip shape of No. 0406 were formed.

[0009] Then, these carbide tool bases A1 to A8 and B1 to B6 are ultrasonically cleaned in acetone and dried, and each is charged into an arc ion plating apparatus shown in FIG. Ti-Al-M alloys having various component compositions were mounted as electrodes (evaporation sources), and the inside of the apparatus was evacuated and maintained at a vacuum of 1 × 10 ^-5 torr while the inside of the apparatus was heated to 500 ° C. After heating,
Ar gas was introduced into the apparatus and 1 × 10 ⁻³ torr of Ar was introduced.
In this state, a bias voltage of -800 V was applied to the cemented carbide tool base to wash the surface of the cemented carbide tool base with Ar gas bombarding. Then, nitrogen gas or nitrogen gas and methane gas were introduced into the apparatus as a reaction gas. 5 × 10 ^-3
At the same time as the reaction atmosphere of torr, the bias voltage applied to the cemented carbide tool base was reduced to -200 V to generate an arc discharge between the cathode electrode and the anode electrode. And B1 to B
On each surface of No. 6, a deposited hard layer having a composition and an average layer thickness shown in Tables 3 and 4 was formed to obtain coated carbide tool bases 1 to 22, and subsequently, a coated super hard layer formed of the deposited hard layer was formed. Each of the hard tool substrates 1 to 22 was subjected to a heat oxidation treatment under the conditions shown in Table 5, and the coated hard layers were each formed as a heat oxidized layer, thereby producing coated carbide cutting tools 1 to 22 of the present invention. . Also, for comparison purposes,
As the cathode electrode (evaporation source) mounted on the arc ion plating apparatus, a Ti—Al alloy having various component compositions was used, and a deposited hard layer having a composition and an average layer thickness as shown in Tables 6 and 7 was used. The conventional coated carbide cutting tools 1 to 22 were manufactured under the same conditions except that the formed hard layer was not subjected to the heat oxidation treatment. The structure of the heated oxide layer of each of the coated carbide cutting tools 1 to 22 of the present invention obtained as a result was observed with an electron probe X-ray microanalyzer and an X-ray diffractometer. M) NO or (Ti,
Al, M) CNO with fine Ti oxide and A
It was confirmed that 1 oxide and M oxide had a structure in which they were dispersed and distributed.

[0010] Of the various coated carbide cutting tools obtained as a result, the coated carbide cutting tools 1 to 18 of the present invention and the conventional coated carbide cutting tools 1 to 16 are as follows: Work material: square material of JIS S50C , Cutting speed: 300 m / min, feed: 0.25 mm / tooth, cutting depth: 2.5 mm, dry milling test of carbon steel was performed, and the coated carbide cutting tools 17 to 22 of the present invention and the conventional coated super For hard cutting tools 17 to 22, Work material: JIS SCM440 round bar, Cutting speed: 300 m / min, Feed: 0.2 mm / rev, Cutting depth: 1.5 mm, Dry continuous cutting of alloy steel under the following conditions: Tests were performed, and in each cutting test, the cutting time until the flank wear width of the cutting edge reached 0.2 mm was measured. Table 8 shows the results of these measurements.

[0011]

[Table 1]

[0012]

[Table 2]

[0013]

[Table 3]

[0014]

[Table 4]

[0015]

[Table 5]

[0016]

[Table 6]

[0017]

[Table 7]

[0018]

[Table 8]

[0019]

From the results shown in Tables 1 to 8, all of the coated carbide cutting tools 1 to 22 according to the present invention are the conventional coated carbide cutting tools 1 in continuous cutting and intermittent cutting (milling) of steel.
It is evident that they show superior wear resistance as compared to # 22. As described above, the coated carbide cutting tool of the present invention
By constituting the hard coating layer with the above-mentioned heat-oxidized layer, it becomes possible to have excellent wear resistance, thereby significantly extending the service life.
It is possible to respond satisfactorily to energy saving and labor saving.

[Brief description of the drawings]

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

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C23C 14/58 C23C 14/58 A

Claims (1)

[Claims] 1. A tool base comprising a tungsten carbide based cemented carbide or a titanium carbonitride based cermet,
In the surface-coated cemented carbide cutting tool obtained by forming a hard coating layer with an average layer thickness of 0.5 to 15 m, the hard coating layer, the composition _{formula: (Ti a Al b M c} ) N, and the composition formula _{: (Ti a Al b M c} ) C d N 1-d, ( provided that an atomic ratio, a: 0.2~0.6, b: 0.1
~ 0.79, c: 0.01 ~ 0.3, a + b + c = 1,
d: 0.01 to 0.5, M is Mg, Ca, S
r, or any one of Si), a single-layer or a double-layer of one of the composite nitrides and carbonitrides of Ti, Al, and M represented by It is composed of a heating oxide layer of a hard layer.
A surface excellent in wear resistance, characterized by having a structure in which fine Ti oxide, Al oxide and M oxide are dispersed and distributed on a substrate made of a composite oxynitride or carbonitride of i, Al and M Coated cemented carbide cutting tool.