JPH10251831A - 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 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=1 and d is 0.01 to 0.5 are satisfied, and M denotes any one kind among the groups 4a, 5a and 6a elements excluding Ti in a Periodic Table), and 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, and M is an element of Groups 4a, 5a, and 6a of the periodic table excluding Ti, that is, Zr, H
f, V, Nb, Ta, Cr, Mo, and W), and a composite nitride and composite carbonitride of Ti, Al, and M [hereinafter, (Ti, A
l, M) N and (Ti, Al, M) CN], and a single layer or two or more layers thereof, which are then placed in an oxidizing atmosphere under reduced pressure or pressure. , 300-1
After holding at a predetermined temperature in the range of 000 ° C. for a predetermined time and then performing heating and oxidizing treatment for cooling, the above (Ti, Al, M) N and (Ti, Al, M) CN in the coated carbide cutting tool are obtained.
Is formed of a composite nitride of Ti, Al and M [hereinafter, referred to as (Ti, Al, M) NO] and a composite carbonitride [hereinafter, referred to as (Ti, Al, M) CNO] A heat-oxidized layer having a structure in which fine Ti oxide, Al oxide and M oxide are dispersed and distributed on a base material comprising: a coated carbide cutting tool in which the hard coating layer comprises the above-described heat-oxidized layer Has shown excellent wear resistance in continuous cutting and intermittent cutting, and has obtained a research result that exhibits 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 is satisfied, and M is any one of Group 4a, 5a, and 6a elements of the periodic table excluding Ti
(Ti, Al, M) N and (Ti, Al, M) CN represented by the following formula: And a constituent layer of the heat-oxidized layer is a fine Ti on a substrate made of (Ti, Al, M) NO or (Ti, Al, M) CNO.
Characterized by coated carbide cutting tools with excellent wear resistance, formed by forming a hard coating layer having a structure in which oxides, Al oxides and M oxides are dispersed and distributed, with an average layer thickness of 0.5 to 15 μm. It has.

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 A10 made of a WC-based cemented carbide having a chip shape of PGA120408 were formed. In addition, TiCN having an average particle size of 0.5 to 2 μm (TiC / TiN = 50/50 by weight) is used as the raw material powder.
Powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC
Powder, WC powder, Co powder, and Ni powder,
These raw material powders are blended in the blending composition shown in Table 2,
After wet mixing with a ball mill for 24 hours and drying, 1 to
The green compact is press-molded at a pressure of n / cm ² , and the green compact is heated to 1540 ° C. in a nitrogen atmosphere of 10 torr.
After sintering under the condition of holding time, and after sintering, R: 0.
03 honing process, ISO standard, CNMG1
Carbide tool bases B1 to B6 made of TiCN-based cermet having a chip shape of 20406 were formed.

Next, the carbide tool bases A1 to A10
B1 and B1 to B6 were ultrasonically cleaned in acetone and dried, and charged into the arc ion plating apparatus shown in FIG. 1, respectively, while the cathode electrode (evaporation source)
After heating the inside of the apparatus to 500 ° C. with a heater while exhausting the inside of the apparatus and maintaining a vacuum of 1 × 10 ⁻⁵ torr, Ar A gas was introduced into the apparatus to form an Ar atmosphere of 1 × 10 ⁻³ torr.
The surface of the cemented carbide tool substrate was cleaned by Ar gas bombardment by applying a bias voltage of 5 ×, and then a nitrogen gas or a mixture of nitrogen gas and methane gas was introduced into the apparatus as a reaction gas to obtain 5 × 10
^-3 torr reaction atmosphere, and a bias voltage applied to the cemented carbide tool base is reduced to -200 V to generate an arc discharge between the cathode electrode and the anode electrode. ~ A10 and B1
A coated hard layer having a composition and an average layer thickness shown in Tables 3 and 4 was formed on each surface of each of Nos. To B6 to obtain coated carbide tool bases 1 to 24, and subsequently, a coating for forming the deposited hard layer. Each of the cemented carbide tool bases 1 to 24 is subjected to a heating oxidation treatment under the conditions shown in Table 5 to produce the coated hard cutting tools 1 to 24 according to the present invention, respectively, by using the deposited hard layers as heated oxidation layers. did. For the purpose of comparison, the cathode electrode (evaporation source) mounted on the arc ion plating apparatus is made of Ti-A having various component compositions.
As an alloy, a vapor-deposited hard layer having the composition and average layer thickness as shown in Tables 6 and 7 was formed, and under the same conditions except that the heat-oxidation treatment was not performed on this vapor-deposited hard layer, Hard cutting tools 1 to 24 were manufactured respectively. In addition,
The structure of the heat-oxidized layer of each of the coated carbide cutting tools 1 to 24 of the present invention obtained as a result was observed with an electron probe X-ray microanalyzer and an X-ray diffractometer. NO or (T
It was confirmed that the substrate composed of (i, Al, M) CNO had a structure in which fine Ti oxide, Al oxide and M oxide were dispersed and distributed.

[0010] Among 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 18 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, a dry continuous milling test of carbon steel was performed.
The coated carbide cutting tools 19 to 24 of the present invention and the conventional coated carbide cutting tools 19 to 24 are as follows: Work material: JIS SCM440 round bar, Cutting speed: 300 m / min, Feed: 0.2 mm / rev, A continuous continuous cutting test of the alloy steel was performed under the following conditions: cutting depth: 1.5 mm, and the cutting time until the flank wear width of the cutting edge reached 0.2 mm was measured in each cutting test. 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 24 of the present invention can be used for continuous cutting and intermittent cutting of steel as compared with the conventional coated carbide cutting tools 1 to 24. It is evident that it exhibits excellent wear resistance. As described above, the coated cemented carbide cutting tool of the present invention has excellent wear resistance by forming the hard coating layer with the above-mentioned heat-oxidized layer, thereby significantly extending the service life. Therefore, it is possible to sufficiently satisfactorily cope with FA and labor saving in cutting.

[Brief description of the drawings]

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

Continued on the front page (51) Int.Cl. ⁶ Identification code 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 is satisfied, and M is any one of Group 4a, 5a, and 6a elements of the periodic table excluding Ti
A composite hard nitride of Ti, Al and M and a composite carbonitride represented by the following formula: The constituent layer of the thermally oxidized layer has a structure in which fine Ti oxide, Al oxide and M oxide are dispersed and distributed on a base material composed of a complex oxynitride or carbonitride of Ti, Al and M. Cutting tool made of cemented carbide with excellent wear resistance.