JP2982359B2 - Cemented carbide with excellent wear and fracture resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cemented carbide suitable for high-efficiency machining, such as high-feed interrupted cutting, having excellent wear resistance and chipping resistance, and high-efficiency, such as high-speed continuous cutting and high-feed interrupted cutting. The present invention relates to a cemented carbide in which a hard layer is coated on the surface of the cemented carbide suitable for processing.

[0002]

2. Description of the Related Art In recent years, titanium carbide (hereinafter, referred to as TiC), titanium carbonitride (hereinafter, referred to as TiCN), titanium nitride (hereinafter, referred to as titanium carbide) has been developed as a cemented carbide having excellent wear resistance and chipping resistance. , TiN) are provided (see JP-A-2-71904) to provide a cemented carbide having improved fracture resistance by incorporating whiskers in a dispersed manner. There is also provided a cemented carbide having a hard layer coated thereon (Japanese Patent Laid-Open No.
-71906).

[0003] The cemented carbide disclosed in Japanese Patent Application Laid-Open No. Hei 2-71904 has Co, Ni, Fe as a binder phase forming component.
One or more of the following (hereinafter referred to as iron group metals): 5 to 20% by weight, and if necessary, as a disperse phase forming component, carbides, nitrides and Ti and Ta, Nb and W Carbonitrides and two or more of these solid solutions (excluding carbides of W, hereinafter referred to as (Ti, T
a, Nb, W) CN), one or more of which are contained in an amount of 0.5 to 30% by weight, with the balance being tungsten carbide as a dispersed phase forming component and unavoidable impurities. The hard alloy contains a whisker of one or more of TiC whiskers, TiCN whiskers, and TiN whiskers as a disperse phase forming component in an amount of 3 to 40% by weight based on the entire cemented carbide. Further, the cemented carbide described in JP-A-2-71906 is provided on the surface of the whisker-dispersed cemented carbide,
An average thickness of 0.5 to 20 μm of a hard layer made of one kind of single layer or two or more kinds of Ti carbides, nitrides, carbonitrides and carbonitrides, and Al ₂ O ₃ It is formed by coating.

[0004]

However, the conventional cemented carbide in which the TiC whiskers, TiCN whiskers and TiN whiskers are dispersed and contained in the cemented carbide has the following problems. (1) TiC whiskers and TiCN whiskers are:
Since the strength of the whisker itself is reduced by reacting with the iron group metal which is a binder phase forming component of the cemented carbide, the cemented carbide in which the TiC whisker and TiCN whisker are dispersed and contained in the base material has a high wear resistance. And lack of fracture resistance,
When this cemented carbide is used as a cutting tool in high-speed continuous cutting or high-feed interrupted cutting under severer conditions than in the past, abnormal wear and chipping tend to occur on the cutting edge. (2) In general, if the whisker is firmly adhered to the dispersion base, sufficient crack resistance cannot be obtained because the propagated crack cuts the whisker. Therefore, in order to improve the fracture resistance of the whisker-containing cemented carbide, it is necessary to disperse and contain even more excellent whiskers,
It is said that if the adhesion between the whisker and the substrate is insufficient and the whisker in the substrate is pulled out when cracks occur, the fracture resistance will be further improved (hereinafter, the strength is increased by pulling out the whisker. The effect of improving the effect is called the extraction effect). However, the above Ti
Since the C whisker and the TiCN whisker have excellent adhesion to the cemented carbide base material, the above-mentioned drawing effect is not sufficiently exhibited. Therefore, the cemented carbide in which the TiC whisker and the TiCN whisker are dispersed and contained is particularly high feed rate. When used for interrupted cutting, fracture resistance cannot be obtained. (3) On the other hand, the TiN whisker exhibits an excellent drawing effect because of its low adhesion and reactivity with the cemented carbide base, but the TiN whisker itself has a low strength, and thus the TiN whisker is dispersed and contained. Hard alloys do not have sufficient wear resistance and fracture resistance.

[0005]

Accordingly, the present inventors have obtained a whisker-dispersed cemented carbide having sufficient wear resistance in high speed cutting and sufficient fracture resistance in high feed interrupted cutting. As a result of conducting research, a TiC whisker having the highest strength among TiC whiskers, TiCN whiskers and TiN whiskers was used as a core, and the surface of this TiC whisker was coated with TiN having low adhesion to the substrate and low reactivity. Whisker (hereinafter referred to as TiN-coated TiC whisker)
Is dispersed in a cermet substrate, and the wear resistance and the wear resistance of the cemented carbide are more excellent than the cemented carbide in which one or more of conventional TiC whiskers, TiCN whiskers and TiN whiskers are dispersed and contained. They have found that they show deficiency.

The present invention has been made based on this finding, and contains one or more of iron group metals: 4 to 15% by weight as a binder phase-forming component. (Ti, T
a, Nb, W) One or more of C · N: 4
0% by weight or less, the balance being a cemented carbide consisting of tungsten carbide as a dispersed phase forming component and unavoidable impurities,
TiN coating TiC as a disperse phase forming component
Whisker accounts for 5 to 30% of the total cemented carbide
The cemented carbide containing the TiN-coated TiC whiskers in a content of 5 to 30% by weight contains T
A known hard layer consisting of a single layer or a multilayer of at least one of carbides, nitrides, carbonitrides, carbonitrides and aluminum oxides of i, Zr, Hf. Cemented carbide also has features.

Next, the reason why the component composition of the cemented carbide of the present invention is limited as described above will be described.

(A) Iron Group Metals These components have the effect of firmly bonding to the dispersed phase and improving the strength and toughness, but the content is 4% by weight.
If the content is less than 15%, the desired effect cannot be obtained. On the other hand, if the content exceeds 15% by weight, the hardness is significantly reduced and the wear resistance is reduced.
It was determined to be 5% by weight.

(B) (Ti, Ta, Nb, W) C.N These components have an effect of increasing the hardness of the alloy and improving the wear resistance. But,
If the content exceeds 40% by weight, the fracture resistance decreases, so the content was determined to be 40% by weight or less.

(C) TiN-coated TiC whiskers These components have the effect of dramatically improving the fracture resistance, as described above, but if the content is less than 5% by weight, the desired excellent fracture resistance is obtained. On the other hand, if the content exceeds 30% by weight, it becomes difficult to uniformly disperse and distribute in the substrate, and local material unevenness occurs. It was determined to be 30% by weight.

[0011]

Next, the present invention will be specifically described based on embodiments.

Example 1 As raw material powders, WC powders each having an average particle diameter in the range of 1 to 5.5 μm, various (Ti, Ta, Nb,
W) Prepare CN powder, Co powder, Ni powder, and Fe powder, and prepare TiN-coated TiC whiskers, TiC whiskers, and TiN whiskers having an aspect ratio (length / diameter) in the range of 10 to 100. did.

Each of these raw material powders was blended into the compositions shown in Tables 1 to 3, wet-mixed for 72 hours in a ball mill, lightly mixed with or without a whisker, dried, and then dried at 10 Ton / cm ^2. Press molding into a green compact at a pressure of 1 × 10 ⁻² torr in a vacuum at a temperature of 1380 to 1400 ° C., or
A hot press is performed under the conditions of a temperature of 1380 to 1400 ° C. and a pressure of 200 kg / cm ² , and the sintered body vacuum-sintered under the above conditions and the hot-pressed body subjected to hot pressing are polished to obtain a chip having a shape of SPP422. To form TiN
The present invention's cemented carbide indexable inserts (hereinafter, referred to as the inventive cemented carbide tips) 1-15 and the comparative cemented carbide indexable inserts (hereinafter, referred to as the comparative cemented carbide tips) 1-2 containing the coated TiC whiskers dispersed therein. , And conventional cemented carbide indexable tips (hereinafter referred to as conventional cemented carbide tips) 1 to 9 containing dispersed TiC whiskers or TiN whiskers, respectively.

The above-mentioned carbide tips 1 to 15 of the present invention
The TiN-coated TiC whiskers are dispersed and contained in the range of 5 to 30% by weight of the total cemented carbide satisfying the conditions of the present invention, and each of the comparative cemented carbide tips 1 and 2 has a weight of 5% outside the range of the present invention. % And 30% by weight
Super-TiN-coated TiC whiskers are dispersed and contained.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

[Table 3]

[0018] The thus various hard tip that is manufactured, cutting test A Workpiece: SCM440 (hardness: H _B 200) square bar of cutting speed: 150 meters / min, Feed: 0.5 mm / rev, A high feed intermittent cutting test of steel was performed under the following conditions: cutting depth: 2 mm, cutting oil: none, measuring the cutting time until the flank wear width reached 0.3 mm, observing the cutting edge condition, and observing these results. The results are shown in Tables 4 and 5.

[0019]

[Table 4]

[0020]

[Table 5]

From the results shown in the above Tables 1 to 5, Ti
Each of the cemented carbide tips 1 to 15 of the present invention containing 5 to 30% by weight of N coating whiskers contains ordinary TiC.
It can be seen that the cutting time until the flank wear width reaches 0.3 mm in the high feed intermittent cutting is longer than that of the conventional carbide tips 1 to 9 dispersedly containing whiskers or TiN whiskers, and the cutting edge condition is good.

Further, even if the cemented carbide chip contains a TiN-coated TiC whisker dispersed in a base material,
When the dispersed content is less than 5% by weight, the fracture resistance is poor. On the other hand, when the dispersed content is more than 30% by weight, the cutting edge wear becomes uneven and cannot be used as a cutting tool.

Example 2 The cemented carbide chips 10, 12 and 15 of the present invention prepared in Example 1, the comparative cemented carbide chips 1 and 2, and the conventional cemented carbide chips 8 and 9 were used as bases, and ordinary chemical vapor deposition was performed on the surface thereof. Coated cemented carbide chips of the present invention (hereinafter referred to as comparative coated chips) 16 to 24 and comparative coated cemented carbide chips (hereinafter referred to as comparative coated chips) having coating layers having the component compositions shown in Tables 6 and 7 by using the method. ) 3
To 4 and conventional coated cemented carbide tips (hereinafter referred to as conventional coated tips) 10 to 18 were produced.

[0024] Using these various coated chip, exactly performs high feed intermittent cutting under the same conditions as the cutting test A of Example 1, further, cutting test B Workpiece: SCM415 (hardness: H _B 0.99) , Round bar, cutting speed: 250m / min, feed: 0.2mm / rev, depth of cut: 1.5mm, cutting oil: yes, high-speed continuous cutting test is performed under the conditions of and the flank wear width reaches 0.3mm The cutting time up to was measured, and the results are shown in Table 8.

[0025]

[Table 6]

[0026]

[Table 7]

[0027]

[Table 8]

From the results shown in Tables 6 to 8, the wear resistance is improved as a whole by coating the surface with a hard layer, but the coated tips 16 to 24 of the present invention provided with a coating layer having the same composition and the conventional coated tips Chip 10
-18, the coated tips 16-24 of the present invention
It can be seen that all of them have better wear resistance and chipping resistance than the conventional coated tips 10 to 18. Furthermore, it can be seen that the comparative coated tips 3 and 4 containing the TiN-coated TiC whiskers in a content deviating from 5 to 30% by weight of the present invention are all inferior in performance as cutting tools.

[0029]

Since the cemented carbide of the present invention has excellent wear resistance and chipping resistance, when it is used as a cutting tool, it takes a long time compared to conventional whisker-containing cemented carbides. It exhibits excellent cutting performance and brings excellent industrial effects.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ identification code FI C22C 1/05 C22C 1/05 G 29/08 29/08 (58) Investigated field (Int.Cl. ⁶ , DB name) C22C 1/05 C22C 1/09 C22C 29/08 B22F 7/00 B23B 27/14

Claims (4)

(57) [Claims] 1. A binder phase-forming component containing one or more of Co, Ni and Fe: 4 to 15% by weight, the remainder comprising tungsten carbide as a dispersed phase-forming component and unavoidable impurities. In a cemented carbide comprising a tungsten carbide-based cemented carbide having a composition and 5 to 30% by weight of whisker as a disperse phase forming component in the whole alloy, the whisker is titanium carbide coated with titanium nitride. A cemented carbide with excellent wear and fracture resistance, which is a whisker. 2. As a binder phase forming component, one or more of Co, Ni and Fe: 4 to 15% by weight, and as a dispersed phase forming component, Ti, Ta, Nb.
And one or more of carbides, nitrides, carbonitrides, and two or more solid solutions thereof (excluding carbides of W) of W and W: not more than 40% by weight, A cemented carbide containing 5 to 30% by weight of a whisker as a dispersed phase forming component in a tungsten carbide based cemented carbide having a composition comprising tungsten carbide as a dispersed phase forming component and unavoidable impurities. Wherein the whisker is a titanium carbide whisker coated with titanium nitride, wherein the cemented carbide is excellent in wear resistance and fracture resistance. 3. The surface of the cemented carbide according to claim 1, wherein Ti, Z
It is characterized by being coated with a hard layer composed of a single layer of at least one of carbides, nitrides, carbonitrides and carbonitrides of r and Hf, and aluminum oxide, or a multilayer of at least two of them. Cemented carbide with excellent wear and fracture resistance. 4. The surface of the cemented carbide according to claim 2, wherein Ti, Z
It is characterized by being coated with a hard layer composed of a single layer of at least one of carbides, nitrides, carbonitrides and carbonitrides of r and Hf, and aluminum oxide. Cemented carbide with excellent wear and fracture resistance.