JP2000176706A - Cutting tool made of surface covering cemented carbide in which hard covering layer exercises excellent anti- defective property - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tool made of a surface covering cemented carbide in which a hard covering layer exercises an excellent anti-defective property. SOLUTION: This cutting tool made of a surface covering cemented carbide is composed by forming a TiCN layer of a longitudinally growing crystal formation with the mean thickness of 5 to 20 μm, in a chemical evaporation or a physical evaporation, as a hard covering layer, on the surface of a superhard base body, through the first layer consisting of one layer or more than two layers, of a TiC layer, a TiN layer, and TiCN layer, with the mean thickness of 0.1 to 5 μm, and furthermore, by forming an Al2O3 layer with the mean thickness of 1 to 15 μm, in the chemical evaporation or the physical evaporation, on the TiCN layer, through the second close contact layer with the mean thickness of 0.1 to 5 μm, and consisting of a TiCO layer, or two layer formation of a TiCO layer and a Ti2O3 layer practically, and the rate of the Ti2O3 layer is 10 to 50 mol% in the total amount with the rate of the TiCO layer, or the TiCNO layer, and the whole mean layer thickness of those hard covering layers is made 6 to 35 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vertically-grown titanium carbonitride layer (hereinafter referred to as l-type) constituting a hard coating layer.
TiCN layer) and aluminum oxide layer (hereinafter, Al
₍ Shown as ₂ O ₃ layer) has excellent interlayer adhesion, and therefore, in a state where the hard coating layer is thickened, intermittent cutting of steel or cast iron, for example, is performed under heavy cutting conditions such as high feed or high cutting. In the case where the hard coating layer is not peeled off, and as a result, the occurrence of defects such as chipping or chipping (micro chipping) due to the peeling becomes significantly suppressed,
The present invention relates to a surface coated cemented carbide cutting tool (hereinafter referred to as a coated cemented carbide tool) that enables a prolonged service life.

[0002]

2. Description of the Related Art Conventionally, a tungsten carbide-based cemented carbide substrate (hereinafter simply referred to as a cemented carbide substrate) is generally provided on a surface thereof with a hard coating layer having an average layer thickness of 0.1 to 5 μm. Titanium carbide layer having a granular crystal structure (hereinafter referred to as Ti
C layer), a titanium nitride layer (hereinafter also referred to as a TiN layer), and a first adhesion layer composed of one or more layers of a titanium carbonitride layer (hereinafter, referred to as a TiCN layer) , 1-TiCN with an average layer thickness of 5-20 μm
A layer is formed by chemical vapor deposition or physical vapor deposition. (B) Further, on the l-TiCN layer, a titanium carbonate layer having a granular crystal structure having an average layer thickness of 0.1 to 5 μm (hereinafter referred to as TiCO)
Layer) or a titanium oxycarbonitride layer (hereinafter referred to as TiCNO).
1 to 15 μm via a second adhesive layer consisting of
An Al ₂ O ₃ layer having a granular crystal structure having an α-type or κ-type crystal structure having an average layer thickness of chemical vapor deposition or physical vapor deposition is formed by the chemical vapor deposition or physical vapor deposition.
A coated carbide tool having a thickness of about 35 μm is known, and it is also known that the coated carbide tool is used for continuous cutting or intermittent cutting of, for example, steel or cast iron. Further, for example, Japanese Patent Application Laid-Open Nos. Hei 3-87369 and Hei 6-80
08, etc., in the hard coating layer of the coated cemented carbide tool, the TiCN layer of the granular crystal structure contains, for example, methane as a reaction gas at a high temperature of 1000 ° C. or more by a chemical vapor deposition apparatus. The l-TiCN layer is formed by using a mixed gas, and the l-TiCN layer is formed by performing chemical vapor deposition in a medium temperature range of 700 to 950 ° C. using a mixed gas containing an organic carbonitride as a reaction gas. It is also well known that the application of the l-TiCN layer improves the toughness of the hard coating layer, so that the occurrence of chipping or chipping (small chipping) in the cutting edge portion is significantly suppressed. It is also known to be.

[0003]

On the other hand, cutting tools in recent years have been strongly demanded to have a longer service life in terms of labor saving and energy saving of cutting work and further cost reduction.
Along with this, the hard coating layer of the coated cemented carbide tool, that is, the l-TiCN layer and the Al ₂ O ₃ layer, which are the constituent layers thereof, tend to be thick, but in a state where the hard coating layer is thickened. ,
For example, when performing intermittent cutting of steel or the like under heavy cutting conditions such as high feed and high cutting, conventional coated carbide tools have
Due to insufficient adhesion of the TiCO layer and the TiCNO layer (second adhesive layer) to the TiCN layer and the Al ₂ O ₃ layer, chipping and chipping are likely to occur in the cutting edge portion, and the service life is shortened in a relatively short time. Is the current situation.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above viewpoint, the TiCO layer and the TCO layer, which are the second adhesion layers, which constitute the hard coating layer of the conventional coated carbide tool described above.
Focusing on the iCNO layer, its l-TiCN layer and Al
As a result of conducting research to further improve the adhesion to the ₂ O ₃ layer, (1) a titanium dioxide (Ti ₂ O ₃ ) phase having a granular crystal structure is mixed in the TiCO layer and the TiCNO layer. Therefore, assuming that it has a two-phase structure of a TiCO phase or a TiCNO phase and a Ti ₂ O ₃ phase, the Ti ₂ O ₃ phase becomes l- in coexistence with the TiCO phase or the TiCNO phase.
Both the TiCN layer and the Al ₂ O ₃ layer have the TiC layer.
Contribute to a further improvement in the adhesion as compared with the single phase layer of the O phase or TiCNO phase. (2) (a) The two-phase structure layer of the TiCO phase and the Ti ₂ O ₃ phase is formed by a chemical vapor deposition method or a physical vapor deposition method with a reaction gas composition (% by volume, the same applies hereinafter) -TiCl ₄ : 0.1 ~ 5%,
_{CO 2: 0.1~0.3%, CH 4} : 0.5~2.5
%, CO: 0.5-2.5%, optionally HCl:
0.1 to 1%, H ₂ or H ₂ + Ar: the remaining (wherein A
(In the case of containing r, 10 to 50% of the total amount), Atmospheric temperature: 850 to 1100 ° C., Atmospheric pressure: 30 to 400 Torr, (b) In addition, _{2 of} TiCNO phase and Ti ₂ O ₃ phase phase tissue layer, also by a chemical or physical vapor deposition method, a reactive gas composition -TiCl _4: 0.1~5%, CO
_{2: 0.1~0.3%, N 2:} 20~50%, CH 4:
0.5~2.5%, CO: 0.5~2.5%, HCl if necessary: 0.1~1%, H ₂ or H ₂ + Ar: the whole case of the remaining (but Ar containing 5 to 2 in proportion
0%), atmosphere temperature: 850 to 1100 ° C., atmosphere pressure: 30 to 400 Torr. In this case, in order to secure excellent adhesion while maintaining the strength of the layer itself. It is necessary to adjust the above conditions so that the Ti ₂ O ₃ phase is present at a ratio of 10 to 50 mol%. (3) Therefore, the thickness of the l-TiCN layer and the Al ₂ O ₃ layer constituting the hard coating layer of the coated cemented carbide tool is increased, that is, if the average layer thickness of the l-TiCN layer is, for example, 10
２０20 μm, and in the case of the Al ₂ O ₃ layer,
Even if the thickness is increased to 5 μm, if the two-phase structure layer of the above-mentioned TiCO phase or TiCNO phase and Ti ₂ O ₃ phase is interposed as a second adhesion layer between these layers, intermittent cutting of steel or the like can be performed at a high feed rate. Even under heavy cutting conditions such as high cutting depth,
Since further excellent adhesion is secured between the l-TiCN layer and the Al ₂ O ₃ layer, chipping or chipping does not occur in the cutting edge portion, and over a long period of time. The research results show that they will exhibit excellent cutting performance.

The present invention has been made on the basis of the above-mentioned research results, and (a) TiC having an average layer thickness of 0.1 to 5 μm as a hard coating layer on the surface of a super-hard substrate. Layer, TiN layer, and TiCN layer
5 to 2 through the first adhesive layer composed of two or more layers.
Forming an l-TiCN layer having an average layer thickness of 0 μm by chemical vapor deposition or physical vapor deposition;
On the layer, it has an average layer thickness of 0.1 to 5 μm and substantially consists of a two-phase structure of a TiCO phase or a TiCNO phase and a Ti ₂ O ₃ phase, and the ratio of the Ti ₂ O ₃ phase is The Ti
1% of the total amount with the CO phase or TiCNO phase
1 to 15 μm via the second adhesion layer which is 0 to 50 mol%
An Al ₂ O ₃ layer having an average layer thickness of m is formed by chemical vapor deposition or physical vapor deposition. (c) The hard coating layer having an overall average layer thickness of 6 to 35 μm has excellent fracture resistance. It is characterized by the coated carbide tool to be exhibited.

[0006] In the coated carbide tool of the present invention,
Substantially TiCO phase or TiC constituting the hard coating layer
The second contact layer having a dual phase structure of NO phase and Ti ₂ O ₃ phase, l-T by the presence of the street the Ti ₂ O ₃ phase
The adhesion to the iCN layer and the Al ₂ O ₃ layer is significantly improved. In this case, if the proportion of the Ti ₂ O ₃ phase is less than 10 mol% in the total amount of the TiCO phase or the TiCNO phase, If the desired excellent interlayer adhesion cannot be ensured, and if the ratio exceeds 50 mol%, the softening of the layer itself progresses rapidly and causes delamination, so that the ratio is reduced. It is determined to be 10 to 50 mol%, preferably 15 to 30 mol%. Further, the reason why the average layer thickness of the second adhesion layer is set to 0.1 to 5 μm is that if the thickness is less than 0.1 μm, a desired excellent interlayer is formed between the l-TiCN layer and the Al ₂ O ₃ layer. If the adhesion cannot be ensured, and the thickness exceeds 5 μm,
Since the layer itself does not necessarily have high strength, the reason is that chipping or chipping (small chipping) easily occurs in the cutting edge due to this, and preferably 0.2 to
The thickness is preferably 0.7 μm.

The first adhesion layer, which also forms the hard coating layer, has a function of firmly adhering to both the super-hard substrate and the l-TiCN layer and improving the adhesion between these layers. If the average layer thickness is less than 0.1 μm, the desired excellent interlayer adhesion cannot be ensured. On the other hand, if the average layer thickness exceeds 5 μm, the wear progress of the hard coating layer is promoted. , The average layer thickness of which
It was determined as 1 to 5 μm.

Further, the l-TiCN layer has the effect of further improving the chipping resistance of the hard coating layer as described above. However, if the average layer thickness is less than 5 μm, the desired effect of improving the chipping resistance is not obtained. On the other hand, if the average layer thickness exceeds 20 μm, the abrasion resistance rapidly decreases. Therefore, the average layer thickness is set to 5 to 20 μm.

Similarly, the Al ₂ O ₃ layer has an effect of improving the wear resistance of the hard coating layer, but has an average layer thickness of 1 μm.
If it is less than m, it is not possible to secure desired excellent wear resistance. On the other hand, if the average layer thickness exceeds 15 μm, chipping tends to occur on the cutting edge, so that the average layer thickness is 1 to 15 μm. I decided.

The hard coating layer has an average thickness of 6 to 35 μm.
When the thickness is less than 6 μm, the desired excellent wear resistance cannot be secured, while the thickness is 3 μm.
If the thickness exceeds 5 μm, chipping or chipping of the cutting edge is likely to occur, and it is preferably 7 to 30 μm.
It is good to do.

Further, a TiN layer having an average thickness of 0.1 to 2 μm may be formed on the Al ₂ O ₃ layer, if necessary, so that the TiN layer has a golden color tone. The reason is that the color tone makes it easy to distinguish between before and after the use of the tool. In this case, if the layer thickness is less than 0.1 μm, the color tone is insufficiently applied, while the color tone is applied to 2 μm. Average layer thicknesses up to are sufficient.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the coated carbide tool of the present invention will be specifically described with reference to examples. Medium-sized WC powder having an average particle diameter of 2.8 μm, 4.9 μm as the raw material powder
m of coarse WC powder, 1.5 μm of (Ti, W) C (the same in weight ratio, hereinafter, TiC / WC = 30/70) powder,
1.2 μm (Ti, W) CN (TiC / TiN / W
C = 24/20/56) powder, 1.2 μm (Ta,
Nb) C (TaC / NbC = 90/10) powder and Co powder of 1.1 μm 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. After that, ISO ・ CNMG12040
8 (for carbide substrates A to D) and SEEN42AFTN
Press molded into a green compact having the shape defined in No. 1 (for the super hard substrate E), and the green compact was vacuum-sintered under the conditions shown in Table 1 to produce super hard substrates A to E, respectively. Further, the above-mentioned super hard substrate B was subjected to 100 Torr CH.
After holding at a temperature of 1400 ° C. for 1 hour in a ₄ gas atmosphere, a slow cooling carburization treatment is performed, and after the treatment, carbon and Co adhering to the surface of the carbide substrate are removed from the surface by acid and barrel polishing. Maximum Co content at 11 μm: 1
A Co-enriched zone of 5.9% by weight and a depth of 42 μm was formed on the surface of the substrate. In addition, the above-mentioned carbide substrates A and D include:
As-sintered, a Co-enriched zone having a maximum Co content of 9.1% by weight and a depth of 23 μm was formed on the surface at a position 17 μm from the surface, and the remaining carbide substrates C and E were formed. Has no formation of the Co-enriched zone and has an overall homogeneous structure. Table 1 shows the internal hardness (Rockwell hardness A scale) of each of the carbide substrates A to E.

Then, the surfaces of these superhard substrates A to E are honed and are shown in Tables 4 and 5 under the conditions shown in Tables 2 and 3 using a conventional chemical vapor deposition apparatus. By forming a hard coating layer having a target composition and a target average layer thickness, coated carbide tools 1 to 10 of the present invention and conventional coated carbide tools 1 to 10 were manufactured, respectively. The coated carbide tools 1 to 10 of the present invention and the conventionally coated carbide tools 1 to 10
For the constituent layers of the hard coating layer, the cross-section after the layer was formed was observed by X-ray diffraction and an optical microscope, and the composition and average layer thickness were measured. The result was almost the same as the target composition and target average layer thickness. And T in the second adhesion layer constituting the hard coating layer of the coated carbide tools 1 to 10 of the present invention.
When the ratio of the i ₂ O ₃ phase was also measured by using an image analyzer together, all the values showed the same value as the target content ratio.

Next, the coated carbide tools 1 to 10 according to the present invention will be described.
And for the conventional coated carbide tools 1 to 10, Work material: JIS SNCM440 (Hardness: HB 230)
Round bar with four longitudinal grooves at equal intervals in the longitudinal direction, Cutting speed: 200 m / min. Infeed: 3 mm Feed: 0.2 mm / rev. , Cutting time: 10 minutes, Dry intermittent high-incision cutting test of alloy steel under the following conditions: Work material: JIS SCM440 (Hardness: HB220) Four round grooves with longitudinal grooves at regular intervals in the longitudinal direction Cutting speed: 200 m / min. Infeed: 0.6 mm / rev. The cutting time: 10 minutes, a dry intermittent high-feed cutting test was performed on the alloy steel under the following conditions, and the flank wear width of the cutting edge was measured in each cutting test. Table 6 shows the measurement results.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

[Table 3]

[0018]

[Table 4]

[0019]

[Table 5]

[0020]

[Table 6]

[0021]

From the results shown in Tables 4 to 6, it can be seen that Ti ₂ O _{3 is located} between the 1-TiCN layer and the Al ₂ O ₃ layer in the hard coating layer.
Coated Carbide Tools 1 to 10 of the Invention Interposed with a Second Adhesive Layer Having a Two-Phase Structure of a Phase and a TiCO or TiCNO Phase
Compared with the conventional coated carbide tools 1 to 10 in which the second adhesion layer is made of a TiCO layer or a TiCNO layer,
Since the N layer and the Al ₂ O ₃ layer have much better interlayer adhesion, the hard coating layer is also caused by intermittent high-feed cutting and intermittent high-cut cutting, which are severe cutting conditions. While excellent cutting performance is exhibited over a long period of time without chipping or chipping, the conventional coated carbide tools 1 to 10 have an interlayer between the l-TiCN layer and the Al ₂ O ₃ layer. It is clear that peeling occurs in any of the hard coating layers due to insufficient adhesion, which causes chipping or chipping, and leads to a relatively short service life. As described above, the coated carbide tool of the present invention
Since the constituent layers of the hard coating layer have excellent interlayer adhesion to each other, for example, continuous cutting and interrupted cutting under ordinary conditions such as steel or cast iron, of course, particularly, these cutting conditions are extremely severe. Even under intermittent heavy cutting conditions, the cutting edge does not suffer from chipping or chipping, etc., and exhibits excellent cutting performance over a long period of time. This contributes sufficiently to cost reduction.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) BA18 BB02 BC04 CA13 CA14

Claims (1)

[Claims] 1. A hard coating layer on a surface of a tungsten carbide-based cemented carbide substrate, comprising: (a) a titanium carbide layer, a titanium nitride layer, and a granular crystal structure each having an average layer thickness of 0.1 to 5 μm; Through a first adhesion layer comprising one or more of the titanium carbonitride layers, a titanium carbonitride layer having a vertical growth crystal structure having an average layer thickness of 5 to 20 μm is formed by chemical vapor deposition or physical vapor deposition; (B) Further, on the titanium carbonitride layer having the vertically elongated crystal structure, an average layer thickness of 0.1 to 5 μm, and substantially a titanium carbonate phase or a titanium carbonitride phase and a dititanium trioxide And a granular crystal structure comprising 10 to 50 mol%, wherein the ratio of the dititanium trioxide phase to the total amount of the titanium carbonate phase or the titanium carbonitride oxide phase is 10 to 50 mol%. 1 to 15 μm through the two adhesion layers The aluminum oxide layer of granular crystal structure and chemical vapor deposition or physical vapor deposition formed with HitoshisoAtsu, 6～35Myu the whole average layer thickness of the (c) these hard layer
A cutting tool made of a surface-coated cemented carbide in which the hard coating layer exhibits excellent fracture resistance, where m is used.