JPS5953341B2 - Sintered hard alloy with excellent heat and wear resistance - Google Patents

Description

Detailed Description of the Invention The present invention provides a sintered material that has excellent heat resistance and wear resistance and is suitable for use as cutting tools, wear-resistant tools, and wear-resistant parts that particularly require these properties. It concerns hard alloys.

In general, sintered hard alloys include tungsten carbide (hereinafter referred to as WC)-based cemented carbide, titanium carbide (hereinafter referred to as TiC), and titanium carbide (hereinafter referred to as TiC).
)-based cermets, as well as TiC-titanium nitride (hereinafter referred to as TiN)-based cermets, are known, and these materials have not only been studied in more detail than before, but have also been used in cutting tools, wear-resistant tools, etc. It is used for the production of

However, in all of these sintered hard alloys, the binder phase is formed of iron group metals, so when used in harsh environments with high temperatures and high stress, the binder phase softens. As the plastic deformation progresses, the hardness and strength of the alloy itself inevitably decrease.

Therefore, when these sintered hard alloys are used as cutting tools for, for example, heavy cutting, cutting of difficult-to-cut materials such as Ni-based or Co-based cemented carbide, and high-speed cutting that involves large heat generation, However, it has not been possible to obtain satisfactory results, and it has also been found to be unsatisfactory when used in the production of wear-resistant tools and wear-resistant parts that require strong plastic deformation resistance, wear resistance, and impact resistance at high temperatures. The current situation is that we can only get results.

On the other hand, in recent years, carbides of Ti and W (
A hard alloy has been developed that has a structure in which Ti, W) C is the dispersed phase and W, which has the highest high-temperature strength among metals, is the binder phase. There are two types: those produced by sintering (hereinafter referred to as sintered hard alloys).

The above-mentioned cast hard alloy is Lameller.
Because it has a structure in which coarse primary carbides are mixed in a eutectic structure, it has excellent toughness and high-temperature hardness, but due to poor fluidity (molten metal flowability), The occurrence of casting defects mainly consisting of coarse cavities, segregation, and non-uniformity of the structure is noticeable, and it is unavoidable that significant variations in alloy properties occur due to these factors.

In addition, the sintered hard alloy has an improved structure uniformity and does not have large cavities as seen in the cast hard alloy, but the T
Since it is usually sintered at a temperature of 1500 to 1800 °C, which is significantly lower than the ternary eutectic temperature of i, w, and C, 2700 °C, the resulting alloy does not have a eutectic structure, and Since W itself, which is a binder phase forming component, has poor sinterability, sintering in a normal vacuum or hydrogen atmosphere, combined with the above sintering temperature, results in a hard sintered product with a high density close to the true density. It is difficult to obtain alloys, and many microscopic voids tend to remain in the alloys.

Therefore, raising the sintering temperature may be considered in order to increase the density of the alloy, but in this case, although the microvoids are reduced and the alloy density approaches the true density, there are significant grains in the binder phase and dispersed phase. Growth occurs and the alloy itself becomes extremely brittle.

Therefore, from the above-mentioned viewpoints, the present inventors suppressed grain growth during sintering, improved sinterability, and thereby achieved heat resistance (oxidation resistance) with high density close to true density. As a result of conducting research to obtain a sintered hard alloy with excellent wear resistance and wear resistance, we found that (a) T as a dispersed phase forming component;
A sintered material containing one or more of carbide, carbonitride, and nitride of i (hereinafter collectively referred to as Ti carbon/nitride) and W as a binder phase forming component. When a hardened hard alloy contains one or two of ylumium nitride (hereinafter referred to as YN) and aluminum nitride (hereinafter referred to as AIN), grain growth is suppressed during sintering. Because sinterability is promoted? A sintered hard alloy having a high density close to the true density and excellent oxidation resistance and wear resistance can be obtained.

(b) In addition to the sintered hard alloy obtained in the above (a), carbides, nitrides, and carbonitrides of Zr, Hf, V, Nb, and Dina, and Cr, Mo, and W are added. One or more of the group consisting of carbides (hereinafter collectively referred to as metal carbon/nitride),
When it is contained alone or in the form of a composite solid solution with the above-mentioned Ti carbon/nitride, it not only further suppresses grain growth during sintering, but also further improves wear resistance (hardness). To become a.

The findings shown in sections (a) and (b) above were obtained.

This invention was made based on the above knowledge, and in weight% (hereinafter all % means weight%): (1) Ti carbon/nitride as a dispersed phase forming component: 10
~60%, one or two of YN and AIN: 1 to 10%, and the remainder is W as a binder phase forming component and inevitable impurities.

(2) Ti carbon/nitride as a dispersed phase forming component: 10
~60%, metal carbon/nitride: 0.1~12%, Y
A sintered hard alloy containing 1 to 10% of one or two of N and AIN, with the remainder consisting of W as a binder phase forming component and inevitable impurities.

(3) Ti carbon/nitride as a dispersed phase forming component: 10
~60%, metal carbon/nitride: 0.1~~12%, further contains one or two of YN and AIN: 1~10%, and the rest is A sintered hard alloy having a composition consisting of W as a binder phase forming component and inevitable impurities.

The sintered hard alloy has the above-mentioned features (1) to (3) that are excellent in heat resistance (oxidation resistance) and wear resistance.

In addition, in the sintered hard alloy of this invention, YN and A
The reason why inclusion of IN suppresses grain growth and promotes sinterability is that since YN and AIN themselves have high melting points, the charcoal of Ti, which is the main dispersed phase,・It does not react with nitrides, and exists as independent particles between the main dispersed phase particles, and acts as a kind of barrier against the grain growth of the main dispersed phase, suppressing grain growth, while in the binder phase. This is thought to be due to the fact that some W is dissolved in solid solution and facilitates the diffusion of W atoms, which promotes sintering of W.

Next, the reason why the component composition of the sintered hard alloy of the present invention is limited as described above will be explained.

(a) Ti carbon/nitride All of these components have excellent oxidation resistance and wear resistance, and also have good sinterability with W, which is the binder phase. If it is less than 60%, the W content becomes relatively too large and the desired excellent wear resistance, high temperature hardness, and welding resistance cannot be secured.
If the content exceeds 10%, the content of W becomes relatively too small and the alloy becomes brittle, so the content was set at 10% to 60%.

(b) YN and AIN YN and AIN both have Witzker's hardness: 1
000 to 1,500 kg/vt4, and although it does not have a very high hardness, it is a component with excellent heat resistance and oxidation resistance, and as mentioned above, it suppresses the grain growth of the main dispersed phase particles and has a bonding effect. It has the effect of promoting the sinterability of the W phase itself, but if its content is less than 1%, the desired effect cannot be obtained, while if it is contained in excess of 10%, the bond strength against W At the same time, the wear resistance also decreases, so the content should be reduced by 1.
It was set at ~10%.

(C) Metallic carbon/nitride These components have the uniform effect of suppressing the grain growth of dispersed phase particles and improving the hardness at room temperature and high temperature, so a higher level of wear resistance is particularly required. If the content is less than 0.1%, the desired effect will not be obtained, while if the content exceeds 12%, the wear resistance and acid resistance of the alloy will be reduced. The content was determined to be 0.1 to 12% because the chemical properties of the elements deteriorate.

Next, the sintered hard alloy of the present invention will be explained using examples and comparing with comparative examples.

Example 1 TiC powder with average particle size: 1 μm: 20%, 1.5 μm
Raw material powders with a composition of 5% AIN powder and 5% 0.6 μm W powder were mixed in a wet ball mill, dried, and then compacted at a pressure of 0.7 ton/CTr12. The green compact was then sintered in vacuum at a temperature of 1500°C for 1 hour, and then hot isostatically pressed (HIP) at a temperature of 1400°C for 1 hour. By applying this, the final component composition is substantially the same as the above-mentioned formulation composition, and the size is 4 mm x 8 m.
For hardness and resistance measurement with dimensions m x 24 mm,
and 12.7mm opening x 4.8mm (nose radius: 0
．． An alloy according to the invention was produced for cutting tests with dimensions of 8 mm).

In addition, for the purpose of comparison, the formulation composition was changed to the above TiC powder:
A comparative alloy was manufactured under the same manufacturing conditions as the alloy of the present invention, except that the W powder was 25% and the W powder was 5%.

The resulting alloys of the present invention all have a Witzkars hardness, room temperature hardness: 1270, hardness at 1000°C: 89
0, and also 125 kg/mIL at room temperature, whereas the comparative alloy that does not contain AIN has the same room temperature hardness: 1100.1000°C hardness: 860. It is clear that the wear resistance and strength are significantly improved by the inclusion of AIN.

In addition, for the above-mentioned present invention alloy and comparative alloy, as well as commercially available cemented carbide equivalent to JIS standard P-10, the workpiece material: J
IS-SNCM-8 (Brinell hardness: 320).

Cutting speed: 5Qm/min, depth of cut: 1.5mm, feed: 0, 85mm/rev, cutting time: 30m1n
Cutting tests were conducted under these conditions, and flank wear and crater depth were measured.

The measurement results are shown in Table 1. As shown in Table 1, it is clear that the alloy of the present invention exhibits superior cutting performance not only to comparative alloys but also to commercially available cemented carbide.

Example 2 TiC having an average particle size of 1.5 μm as a raw material powder
Powder 5 Tl (Co-5No-s) powder, and T
iN powder, 0.6 μm W powder, 3 μm YN powder and AIN powder, 1.5 μm (7) ZrC powder,
Zr(CO-8NO-2) powder, ZrN powder, H
fC powder, Hf(Co, 8No-2) powder, Hf
N powder, VC powder, V(CO-9NO-1) powder, VN
Powder, NbC powder, Nb(Co-8NO-2) powder, NbN powder, TaC powder, Ta(Co, 9No, 1
) powder, TaN powder, Cr3C2 powder.

Mo2C powder and WC powder were prepared, these raw material powders were blended into the composition shown in Table 2, and then mixed, dried, and molded under the same conditions as in Example 1.
Then, by sintering, a material for hardness and transverse rupture strength measurement and for cutting test having substantially the same final component composition as the above-mentioned formulation composition and having the same dimensions as in Example 1 was obtained. Invention alloys 1-29 and comparative alloys 1-8
were manufactured respectively.

The resulting invention alloys 1 to 29 and comparative alloy 1
Vickers hardness at normal temperature and 1000℃ of ~8)
The transverse rupture strength at room temperature was measured, and the measurement results are shown in Table 2.

As shown in Table 2, Alloys 1 to 29 of the present invention are Comparative Alloy 1. All of which do not contain YN and AIN. 3.
4. 6. and 8. In addition, Comparative Alloys 5 and 7 have compositions in which the metal carbon/nitride content is higher than the range of the present invention (Comparative Alloys 4 and 8 mentioned above)
The metal carbon/nitride content is also on the high side), and the YN content is significantly higher than Comparative Alloy 2, which has a composition that is on the high side of the range of the present invention. It is clear that it has high strength (transverse rupture strength).

Next, the above-mentioned invention alloys 9 and 15. and 26. Comparative alloys 1 and 5. and 7. Furthermore, regarding commercially available cemented carbide equivalent to JIS standard P-10, work material: JIS 5KD-1
(Brinell hardness 420), cutting speed: 40 m/min,
Depth of cut: 1mm, feed: 0.45mm/rev, .

Cutting time: A cutting test was conducted under the conditions of 3Qmin, and flank wear and crater depth were measured.

The measurement results are shown in Table 3. As shown in Table 3, the same results as in Example 1 were obtained in this case as well.
It is clear that the inventive alloy has superior cutting properties compared to comparative alloys and commercially available cemented carbides.

Example 3 Using a commercially available high-temperature plasma device, A: (Tio, 9W
o, 1) C-5%YN-5Q%W alloy powder (hereinafter referred to as the present invention alloy powder A), B: (Tlo-7TaO-
3) C5%YN-50%W alloy powder (hereinafter referred to as the present invention alloy powder B), C: (Tio, 7WO03) Co
, 5No-23%AlN-70%W alloy powder (hereinafter referred to as the present invention alloy powder C), D: (Tlo-9ZrC1-1) C2%YN-35
% alloy powder (hereinafter referred to as the alloy powder of the present invention), E: (Tlo, 7TaO-2WO-1) Co-
9NO013%AlN-60%W alloy powder (hereinafter referred to as the present invention alloy powder E), F: (Tio, 5Wo, 4Nbo, 1) co, 9No,
1-6% YN-1% AlN-40% W alloy powder (hereinafter referred to as the present invention alloy powder F), G: (Tio-5Wo-ICrQ-s) Co
-eNo-42%YN-1%AlN-60%W alloy powder (hereinafter referred to as the present invention alloy powder G) was prepared, and for the purpose of comparison, under the same conditions except that it did not contain YN and AIN. a: (Tlo-9W0.1) C50%W alloy powder (hereinafter referred to as comparative alloy powder a), b: (Tlo,7TaO-a) C50%W alloy powder (hereinafter referred to as comparative alloy powder), C: (Tlo , 7WO03) Co-8NO-27
0% W alloy powder (hereinafter referred to as comparative alloy powder C), d: (Tio, 9ZrO-1) C35% W alloy powder (hereinafter referred to as comparative alloy powder d), e: (Tio, 7Tao, 2Wo0,) Co, 9No ,
1→0% W alloy powder (hereinafter referred to as comparative alloy powder e), f
:(Tlo-5Wo-4NbO-1) Co, 9NO
-1-40% W alloy powder (hereinafter referred to as comparative alloy powder f)
, g: (Tlo, 5Wo-1Cro-1) Co
-6NO-460)% W alloy powder (hereinafter referred to as comparative alloy powder g)
), respectively, are prepared as raw material powders, these raw material powders are blended in the proportions shown in Table 4, mixed under normal conditions, and then 0.8 tons/
After molding the green compact at a pressure of cm2, in vacuum 1, the temperature:
By sintering at 1500° C. for 1 hour, alloys 1 to 25 of the present invention having substantially the same final composition as the above-mentioned composition and having dimensions of 4 mm x 8 mm x 24 mm were prepared. and Comparative Alloys 1 to 8 were manufactured, respectively.

' When the polished surfaces of all of the resulting Invention Alloys 1 to 25 and Comparative Alloys 1 to 8 were observed under an optical microscope at 200x magnification, no bores were observed in any of the Invention Alloys. In contrast, bores were observed in the comparative alloy that did not contain YN or AIN, indicating poor sinterability.

Table 4 also shows the results of measuring the normal temperature and 1000°C hardness (Witzker's hardness) and transverse rupture strength at room temperature of the invention alloys 1 to 25 and comparative alloys 1 to 8.

As shown in Table 4, it is clear from the comparison between Invention Alloys 1-25 and Comparative Alloys 1-8 that the hardness and transverse rupture strength are significantly improved by the inclusion of YN and AIN. be.

As mentioned above, the sintered hard alloy of the present invention has high density and excellent heat resistance (oxidation resistance) and wear resistance, so it has particularly good plastic deformation resistance and wear resistance at high temperatures. It has industrially useful properties, such as exhibiting extremely excellent performance when used as cutting tools, wear-resistant tools, and wear-resistant parts that require impact resistance.

Claims (1)

[Claims] 1. As a dispersed phase forming component, Ti carbide, carbonitride,
and one or more of nitrides: 10-60
% and one or two of Y and AI nitrides:
A sintered hard alloy having excellent heat resistance and wear resistance, characterized by having a composition (weight percent) of 1 to 10% of tungsten, and the remainder consisting of tungsten, which is a binder phase forming component, and unavoidable impurities. 2. As a dispersed phase forming component, Ti carbide, carbonitride,
and one or more of nitrides: 10-60
% and carbides, nitrides, and carbonitrides of Zr, Hf, V, Nb, and Dina, as well as Cr, MO
, and one or more of the group consisting of carbides of W: 0.1 to 12%, one or two of the nitrides of Y and AI: 1 to 10%, and the remainder A sintered hard alloy with excellent heat resistance and wear resistance, characterized in that it has a composition (the above weight %) consisting of tungsten, which is a binder phase forming component, and unavoidable impurities. 3. As a dispersed phase forming component, Ti carbide, carbonitride,
and one or more of nitrides: 10-60
% and carbides, nitrides, and carbonitrides of Zr, Hf, V, Nb, and Dina, as well as Cr, Mo
, and 21 or 2 of the group consisting of carbides of W
Contains a composite solid solution of 0.1 to 12% of species or more, and further contains one or two of Y and AI nitrides: 1 to
1. A sintered hard alloy having excellent heat resistance and wear resistance, characterized in that it has a composition (the above weight %) consisting of 10% of tungsten and the remainder consisting of tungsten, which is a binder phase forming component, and unavoidable impurities.