JP2002194474A - Tungsten carbide matrix super hard composite sintered body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a WC matrix super hard composite sintered body which has excellent oxidation resistance, corrosion resistance, impact resistance, chipping resistance and wear resistance in particular. SOLUTION: The WC matrix super hard composite sintered body contains a hard phase essentially consisting of WC by 10 to 76 vol.% and a metallic bonding phase consisting of an alloy of one or more kinds selected from iron group metals, and dispersedly contains ceramic hard dispersion particles by 4 to 70 vol.% and one or more kinds selected from the group 4a to 6a elements other than W by >=0.1 vol.% expressed in terms of carbides. At least a part of the group 4a to 6a elements is dispersed into the above ceramics hard dispersion particles. An intermetallic compound is present in the sintered body. Also, the porosity of the sintered body is A02 or lower by the ASTM standard.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tungsten carbide-based (hereinafter referred to as "WC-based") cemented carbide composite sintered body, and more particularly, to oxidation resistance, corrosion resistance, impact resistance, and the like.
The present invention relates to a WC-based cemented carbide composite sintered body having excellent fracture resistance, particularly excellent wear resistance. The cemented carbide composite material of the present invention,
Cutting tools used for high speed cutting, high feed cutting, heavy cutting, etc.,
Jigs and tools used for hot, warm, and cold plastic working and ductile working such as hot rolling rolls, guide rolls, drawing rolls, dies, and punches, and high resistance to bearings, bearing balls, sliding bearings, and sliding guides It can be suitably used as a material for a member requiring abrasion.

[0002]

2. Description of the Related Art Sintered WC super-hard composite materials have excellent toughness and mechanical strength, and have been conventionally used for applications such as cutting tools. On the other hand, a WC-based super-hard composite material sintered body
Although excellent in toughness and mechanical strength as described above, there is a problem that it is difficult to obtain sufficient characteristics in terms of oxidation resistance, chemical stability, high-temperature characteristics, and abrasion resistance. Therefore, members requiring these characteristics, such as tools for warm / hot casting where temperature characteristics are important, bearings, bearing balls, slide bearings, and slide guides that require high wear resistance, etc. There is a problem in use as.

[0003] In order to solve such a problem, a hard layer made of alumina or the like is generally formed on the surface of a cemented carbide. For example, JP-A-63-5
No. 16942 discloses a hard phase composed of WC, Ni,
A cemented carbide tool in which a hard phase such as alumina is coated on a surface of a sintered body mainly composed of a bonding metal phase made of Co using CVD, PVD or the like is described. In addition, Japanese Unexamined Patent Publication
Japanese Patent No. 221373 describes a method in which free carbon is previously contained in a cemented carbide comprising WC and an iron group metal binding phase, and a specific heat treatment is applied to eliminate free carbon, followed by coating with alumina or the like. I have.

[0004] However, the method of coating the surface of the sintered body with the hard phase has a problem that, in addition to an increase in manufacturing cost, when the coated hard phase is worn or peeled off, regeneration by repolishing is not effective.

[0005] Therefore, in order to improve the characteristics of a WC-based super-hard composite material sintered body in consideration of the production cost and regeneration by repolishing, a method of adding and dispersing high-temperature stable alumina or the like as hard particles has been conventionally used. Is being done. For example, JP-A-61-235533 and JP-A-62-14623.
No. 7 discloses a highly heat-resistant superconductor in which hard dispersed particles such as alumina and hard whiskers are uniformly and finely dispersed in a sintered body mainly composed of a hard phase composed of WC and a bonded metal phase composed of iron group or the like. Hard alloys are described. In addition, Tokuhyo Hei 4-502
No. 347 describes a method in which a single crystal reinforcing material such as alumina is dispersed in a sintered body mainly composed of a hard phase composed of WC or the like and a binding metal phase composed of iron or the like.
In addition, Japanese Patent Application Laid-Open No. 9-316589 discloses an Al ₂ powder obtained by adding nano-sized fine Co powder and WC to alumina.
O ₃ -WC-Co-based composite material is described.

However, since hard particles such as alumina have very poor wettability with metals, they are not sufficiently densified simply by being dispersed in a cemented carbide and fired, and the mechanical properties such as strength and hardness are also extremely high. There is a problem that it is significantly reduced as compared with a hard alloy. In addition, since only a small amount can be added and expensive powder materials of special forms such as fine and fine powders are required, it is difficult to effectively improve the wear resistance of the cemented carbide sintered body. There is a problem that there is.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has been developed in consideration of the above-mentioned circumstances. The present invention relates to a WC-based carbide substrate excellent in oxidation resistance, corrosion resistance, impact resistance, fracture resistance, and particularly excellent wear resistance. It is an object to provide a composite material sintered body.

[0008]

Means for Solving the Problems The present inventors have studied the relationship between various components and properties of a WC-based super-hard composite material sintered body, and as a result, have found that a hard phase mainly composed of WC and an iron group metal binding phase. By dispersing the ceramic hard dispersion particles in the cemented carbide sintered body consisting of and by setting the density and the porosity within a predetermined range, it is lighter than the conventional cemented carbide material,
The applicant has filed an application before finding that a cemented carbide-based composite material sintered body having excellent wear resistance, oxidation resistance, corrosion resistance, and fracture resistance can be obtained (Japanese Patent Application No. 2000-27831).

Subsequently, the present inventors have examined the relationship between various components and properties of the WC-based super-hard composite material sintered body, and as a result, have found that a super-hard super-phase composed of a hard phase mainly composed of WC and an iron group metal binding phase. By dispersing the ceramic hard dispersion particles in the alloy sintered body and further containing one or more of the 4a to 6a group elements excluding W in a dispersed manner, the sinterability is further improved, and the abrasion resistance and The inventors have found that a WC-based cemented carbide composite sintered body having excellent oxidation resistance, corrosion resistance, and fracture resistance can be obtained, and completed the present invention.

The WC-based cemented carbide composite material of the present invention is
10 to 76% by volume of a hard phase mainly composed of tungsten carbide (WC), 3 to 20% by volume of a metal bonding phase composed of one or more alloys of iron group metals in the sintered body, and ceramic hard dispersion 4 to 70% by volume of particles and 4a excluding W
One or two or more of Group 6a to 6a elements are contained in an amount of 0.
It is characterized by containing 1% by volume or more dispersedly.

The content of the above-mentioned “hard phase mainly composed of tungsten carbide (WC)” (hereinafter referred to as “WC-based hard phase”) in the WC-based cemented carbide composite material of the present invention is as follows.
10 to 10% by volume of WC-based cemented carbide composite material sintered body
It is 76% by volume, preferably 20 to 70% by volume, more preferably 30 to 65% by volume. If the content of the WC-based hard phase is less than 10% by volume, the toughness of the sintered body is remarkably reduced, and the required fracture resistance and impact resistance cannot be obtained. The content of the WC-based hard phase is 76% by volume.
Exceeds, the hardened particles of the ceramics such as alumina and the metal binder phase composed of one or more alloys among the remaining iron group metals are reduced, and the sinterability is reduced. Is not preferred because of insufficient wear resistance, oxidation resistance and corrosion resistance. In addition, as a method of calculating the value of volume% used in the present specification, there is a method of calculating from the SEM photograph based on the ratio of the area of the particles to the whole area, but the volume% is calculated from the blended addition amount of the raw material powder. % By volume. This is because the WC-based hard phase hardly volatilizes at the time of sintering, and the difference between the prepared composition and the composition after firing is extremely small.

The above-mentioned "metal bonding phase comprising one or more alloys of iron group metals" (hereinafter referred to as "iron group metal bonding phase") which is a component constituting the metal bonding phase of the present invention. Is selected from iron group metals, for example, C
o, Ni, Fe and the like. Among them, Co,
The use of at least one selected from Ni and Fe is preferred from the viewpoint of sinterability. The content of the iron group metal binding phase of the present invention may be selected from the following:
3 to 20% by volume, preferably 5-1 to 100% by volume
It is 7% by volume, more preferably 8 to 15% by volume. If the content of the iron group metal binding phase is less than 3% by volume, sinterability and toughness are reduced, and the fracture resistance required as a sintered body cannot be obtained, which is not preferable. On the other hand, if it exceeds 20% by volume, the hardness of the sintered body is reduced, and the required wear resistance cannot be obtained, which is not preferable.

The "hard ceramic dispersed particles" of the present invention include oxide-based hard dispersed particles (Al ₂ O ₃ , Zr
O ₂ , TiO ₂ , SiO ₂ , Y ₂ O _3, etc.), carbide hard dispersed particles (ZrC, SiC, VC, TiC, etc.), nitride hard dispersed particles (Si ₃ N ₄ , TiN, ZrN, VN, etc.) ) And boron-based hard dispersed particles (WB, MoB, TiB ₂ , Z
rB ₂ etc.) can be used. Among these, oxide-based hard dispersed particles are preferred, and alumina (Al ₂ O ₃ ) hard dispersed particles are most preferred, from the viewpoint of improving wear resistance and reducing manufacturing cost. The “ceramic hard dispersed particles” may be used alone or in combination of two or more. The content of the “ceramic hard dispersed particles” is 4% with respect to 100 vol%
The content is from 70 to 70% by volume, preferably from 10 to 60% by volume, and more preferably from 35 to 55% by volume. When the content of the “hard ceramic dispersed particles” is less than 4% by volume, the amount of the hard ceramic dispersed particles is too small, resulting in desired performance in oxidation resistance, corrosion resistance, and abrasion resistance due to the chemical stability of the ceramic. Is not preferred since On the other hand, if it exceeds 70% by volume, the sinterability and toughness are reduced, and the desired performance in fracture resistance and impact resistance cannot be obtained.

The “ceramic hard dispersed particles” are W
As long as it is present in the C-based cemented carbide composite material sintered body, its existence state is not particularly limited. However, it is preferable that it is homogeneously present in the WC-based cemented carbide composite material sintered body. Where "homogeneous"
"It means that the dispersion state of the ceramic hard dispersion particles is substantially the same inside and outside the WC-based super-hard composite material sintered body. More specifically, when the number of ceramic hard dispersed particles present per 10,000 μm ² of the cross-sectional area of the WC-based cemented carbide composite material sintered body is counted, It refers to the case where the number ratio is in the range of 0.1 to 10.

Further, the above-mentioned “ceramic hard dispersed particles”
The average particle size of is also not particularly limited, but is preferably 0.05 to 50 μm. By setting the content in such a range, the amount of the hard ceramic dispersed particles penetrating into the WC-based cemented carbide composite sintered body becomes sufficient, and the dispersion state becomes uniform, thereby improving the wear resistance of the sintered body. It is preferable because it can be used. Here, the average particle diameter of the “ceramic hard dispersed particles” is observed in a range of 30 μm square from a 5000 times SEM photograph of a cross section (so-called mirror-polished surface) of the WC-based super-hard composite material sintered body. The length of the shortest part (so-called minor axis) of the hard dispersed particles is measured, and the measured value is determined as an average value.

The WC-based cemented carbide composite material of the present invention contains, in addition to the above-described components, "elements of Groups 4a to 6a excluding W" in a dispersed manner. The above “4a to 6 excluding W”
By containing the “a-group element”, it forms a solid solution with the metal binding phase to form an alloy, and the wear resistance, oxidation resistance, corrosion resistance, and the like of the iron group metal binding phase in the WC-based cemented carbide composite material sintered body It is considered that the strength and hardness are improved and the wettability with the ceramic hard dispersed particles is improved. Further, in the WC-based cemented carbide composite material sintered body of the present invention, by dispersing at least a part of the “group 4a to 6a element other than W” in the ceramic hard dispersion particles, the intragranular residual stress is reduced. As a result, the toughness is increased and the grain growth of the hard ceramic dispersed particles is suppressed, and the structure becomes finer, resulting in high strength. As a result, the fracture resistance and impact resistance of the sintered body can be improved. It is preferred.

The “elements of groups 4a to 6a excluding W” of the present invention include, for example, Ti, Zr, Hf, V, Nb,
Ta, Cr and the like can be mentioned, and one or more of them can be used. Among them, particularly, Zr and Hf
Is preferable because it can reduce the ceramics, metallizes the surface of the hard dispersed particles of the ceramics, and significantly improves the wetting with the iron group metal binding phase. There is no particular limitation on the starting material used to cause the sintered body to contain the “group 4a to 6a element excluding W” of the present invention, but preferably, carbides, nitrides, carbonitrides, The above composite carbide, composite nitride, composite carbonitride, pure metal, two or more alloys, two or more intermetallic compounds, intermetallic compound with Al, intermetallic compound with iron group metal, oxide No. Among them, carbides are particularly preferable because they can improve the sinterability and can be made into a sintered body having a high hardness.

The content of the "elements of groups 4a to 6a excluding W" of the present invention is at least 0.1% by volume, preferably 0.3% by volume in terms of carbide, based on 100% by volume of the cemented carbide composite material. As described above, the content is more preferably 0.5 to 2.5% by volume.
If the content of the group 4a to 6a element other than W is less than 0.1% by volume, the amount of solid solution in the metal binder phase is insufficient, so that the strength and hardness of the sintered body cannot be improved. Not preferred. On the other hand, by setting the content of the group 4a to 6a element other than W to 2.5% by volume or less, it is possible to prevent a decrease in sinterability and exhibit excellent fracture resistance and impact resistance. It is preferable because it is possible.

In the cemented carbide composite material of the present invention, an intermetallic compound may be present in the sintered body. By the presence of such an intermetallic compound,
Originally, it is possible to improve the wettability between ceramic hard dispersed particles of alumina or the like having poor wettability with metal and the iron group metal binding phase in the sintered body, and to obtain a denser sintered body. As a result, it is possible to obtain a sintered cemented carbide composite material having extremely excellent high-temperature strength and high-temperature hardness, and further having excellent thermal shock resistance, thermal fatigue resistance, oxidation resistance and corrosion resistance. There is no particular limitation on the method of causing the above-mentioned "intermetallic compound" to be present in the sintered body, and examples thereof include a method of adding the intermetallic compound as a raw material and a method of reacting and depositing the intermetallic compound during firing. Among them, the method of reacting and precipitating an intermetallic compound during firing is preferable because the bonding strength between the metal binder phase and the ceramic hard dispersion particles in the cemented carbide composite material sintered body can be further increased. .

As an example of the above-mentioned "intermetallic compound", preferably, an intermetallic compound of an iron group metal and Al, an intermetallic compound of a group 4a to 6a element and Al, and an intermetallic compound of a group 4a to 6a element and an iron group metal Intermetallic compounds, particularly Ni ₃ Al,
Ni ₃ (Al, Ti), NiAl, TiAl, Ti ₃ A
1, CoAl is preferred from the viewpoint of improving the high-temperature characteristics of the sintered body and improving the bonding strength with the ceramic hard dispersion particles in the cemented carbide composite material sintered body of the present invention. The above-mentioned intermetallic compound contained in the cemented carbide composite material sintered body of the present invention may be one kind, or may contain two or more kinds of different intermetallic compounds.

The sintered body of the cemented carbide-based composite material of the present invention is excellent in sinterability, so that it can be a dense sintered body having few pores. Specifically, the porosity of the cemented carbide composite material sintered body of the present invention is determined by ASTM (American).
Society for Testing and M
(Arials) standard and can be set to a level of A02 or less. By setting the porosity to a level of A02 or less, it is possible to obtain a sintered body having a higher density and fewer pores, and it is possible to maintain excellent strength and hardness, which is preferable.

The WC-based cemented carbide composite material of the present invention comprises:
With the above configuration, it is possible to improve oxidation resistance, corrosion resistance, impact resistance, fracture resistance, and particularly, wear resistance. Specifically, the strength is determined to be 1300 MPa or more (preferably 1400 MPa or more, more preferably 1500 MPa) in a three-point bending test based on JIS R1601.
As described above, most preferably 1600 MPa or more. Further, the fracture toughness is determined by a method based on JIS R1607 in a manner of 10.0 MPa · m ^0.5 or more (preferably 11.0 MPa · m ^0.5 or more, more preferably 1 MPa / m ^0.5 or more).
1.5 MPa · m ^0.5 or more, most preferably 12.0 M
Pa · m ^0.5 or more). Further, the hardness is determined to be 1500H in a method based on JIS R1610.
v or more (preferably 1600 Hv or more, more preferably 1650 Hv or more). Further, the specific wear amount was determined to be 5.0 × 10 ⁻¹⁶ m ² / by the method described in Example.
N or less (preferably 4.5 × 10 ⁻¹⁶ m ² / N or less, more preferably 4.0 × 10 ⁻¹⁶ m ² / N or less). Furthermore, the oxidation increase by the method described in the Examples was 9%.
200 g / m ² or less (preferably 800 g / m ² or less, more preferably 700 g / m ² or less, most preferably 600
g / m ² or less).

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be specifically described with reference to examples and comparative examples. <Experimental Example 1> (1) Preparation of WC-based super-hard composite material sintered body WC, TiC, ZrC, HfC, VC, Nb as raw materials
C, Cr ₃ C ₂ , Mo ₂ C, Ni, Co and Fe (average particle size 0.5 to 3 μm) and Al ₂ O ₃ (average particle size 0.2
μm) and blended it with the composition shown in Table 1 below to prepare a raw material powder mixture. Then, the raw material powder mixture was wet-pulverized using an attritor, the solvent was degassed, dried, and press-molded into a predetermined shape. The obtained press-formed body was placed in a furnace, heated to 1500 ° C. with 70 Pa of argon gas introduced, and further introduced with argon gas and kept at 130 KPa for 90 minutes to obtain the desired WC super Hard base composite material sintered body No. 1 to 23 were obtained.

[0024]

[Table 1]

(2) Evaluation of Performance For 1 to 23, performance evaluation was performed by the following method. The results are shown in Table 2 below. In Table 2, the sample No. Those marked with “*” before are comparative examples outside the scope of the present invention. Sintered body density (g / cm ³ ) Measured using Archimedes' method. Theoretical density ratio (%) The value of the sintered body density obtained above was divided by the value of the theoretical density calculated by the composition mixing rule, and this value was obtained by expressing the value in percentage. Porosity Using a 200 × optical microscope photograph of the polished surface of the sintered body,
Evaluation was performed in light of ASTM B276-79. The presence of Ni ₃ Al phase identification in the sintered body of Ni ₃ Al phase in the sintered body were evaluated to identify the peaks obtained by X-ray diffraction method using Cu-K [alpha radiation source. Observation of Alumina Particles in Sintered Body The inside of alumina particles in the sintered body was observed by STEM (scanning transmission electron microscope), and EDS (energy dispersive X
(A line spectroscopy) measurement confirmed the presence or absence of group 4a to 6a group elements in the alumina grains. Strength (MPa) Determined by a three-point bending test in accordance with JIS R 1601. Fracture toughness (MPa · m ^0.5 ) Measured in accordance with JIS R 1607. Hardness (Hv) Measured by a method based on JIS R 1610. Specific wear (× 10 ⁻¹⁶ m ² / N) Measured by a ring-on-plate method. That is, the above No. 1
To 23 using each of the cemented carbide composites
(0 mm square, 5 mm thick), and a carbon steel ring (outer diameter φ20 mm, inner diameter 15 mm) is placed on top of the ring.
300-600 rpm under a load of 000N
While rotating at a rotation speed of 2 to 5 using water as a lubricant.
Sliding for time. Thereafter, the amount of wear of the plate was determined from the change in weight, and the value was divided by the sliding distance and the load.

[0026]

[Table 2]

<Experimental Example 2> The same raw material as in Experimental Example 1 was used, and was blended with the composition shown in Table 3 below to prepare a raw material powder mixture. Then, the target WC-based cemented carbide composite N
o. 24-27 were obtained. Then, the obtained WC-based cemented carbide composite material No. With respect to 24 to 27, the oxidation increase (g / m ² ) of the WC-based cemented carbide composite sintered body at a high temperature in the atmosphere was measured by the method described below. That is, the WC-based super-hard composite material sintered body No. A small piece of 24 to 27 (2.5 × 2.5 mm square, thickness 1.2 mm) is placed in a platinum container, and is heated from room temperature to 1000 ° C. in the atmosphere.
The temperature is raised at 0 ° C. per minute, and the weight of the small piece is measured with a thermobalance. Then, an increase in oxidation was determined by dividing the change in total weight up to 1000 ° C. by the specific surface area of the sample. In this method, α-alumina was used as a reference material. The results are shown in Table 3 below. In Table 3, the sample No. Those marked with “*” before are comparative examples outside the scope of the present invention.

[0028]

[Table 3]

(3) Effect of Experimental Example As shown in Table 2, No. 1 within the scope of the present invention. 1 to 1
In each of the WC-based cemented carbide composite sintered bodies of No. 4, since the theoretical density ratio is 97.1 to 99.9% and the porosity level is A02 or less, it is dense and excellent in sinterability. You can see that.
Further, the strength is 1340 to 2120 MPa and the fracture toughness is 1
0.1-15.2 MPa · m ^0.5 , hardness 1520-1
990Hv, high, specific wear is 1.6 to 4.5 × 10
^Since it is as low as ^-16 m ² / N, it can be seen that it has sufficient toughness while having high strength and high hardness, and also shows excellent wear resistance. In addition, No. 1 in which an intermetallic compound exists. 1 to
No. 9 which does not exist. When 10 to 14 are compared, N
o. In the case of 10 to 14, the average strength was 1422 MPa, the hardness was 1610 Hv, and the specific wear amount was 3.9 × 10 ⁻¹⁶ m ² / N.
, Whereas No. In the case of 1 to 9, the average strength is 16
72 MPa, high hardness of 1749 Hv, and low specific wear of 3.1 × 10 ⁻¹⁶ m ² / N, the presence of the intermetallic compound further enhanced the strength, hardness and wear resistance. It can be seen that a WC-based super-hard composite material sintered body can be obtained.

On the other hand, no. In the WC-based cemented carbide composite material of No. 15, the WC content was as high as 80% by volume, so that the iron group metal content was reduced. Inferior and porosity is A0
4, the strength is 1210MP due to residual pores
a, The hardness is as low as 1380 Hv, indicating that the strength and hardness are inferior. Furthermore, as a result of the reduced amount of alumina hard dispersed particles, it can be seen that the specific wear amount is as high as 6.1 × 10 ⁻¹⁶ m ² / N, and the wear resistance is reduced. On the other hand, No. 16 WCs
Since the WC content is as small as 7.5% by volume, the abrasion resistance and the hardness of the sintered body of the cemented carbide-based composite material are no. On the other hand, although the strength is slightly improved from 15, the strength is as low as 1220 MPa and the fracture toughness is as low as 8.9 MPa · m ^0.5 , indicating that the toughness of the sintered body is reduced.

Further, No. The WC-based cemented carbide composite material of No. 17 is excellent in strength, toughness, and hardness because the alumina hard dispersed particles are as small as 3% by volume, but the specific wear amount is 8.2 × 10 ⁻¹⁶ m ² / N. It can be seen that the wear resistance is extremely low. On the other hand, No. 18 and no. In the WC-based super-hard composite material sintered compact of No. 21, the alumina hard dispersed particles contained 8
0% by volume, the theoretical density ratio is 92.2% and 9%.
4.2% and low sinterability, strength 1220MPa and 1310MPa, hardness 1320Hv and 1500H
v and low strength and hardness. In addition, it can be seen that the specific wear amount is as high as 6.6 and 9.0 × 10 ⁻¹⁶ m ² / N, and the wear resistance is poor. In addition, No. In the WC-based super hard matrix composite sintered body No. 21, the sinterability is reduced and the toughness is reduced because TiC is as large as 5.0% by volume.

Further, No. In the sintered compact of the WC-based cemented carbide composite material of No. 19, since the iron group metal binding phase was as small as 1.5% by volume, the theoretical density ratio was as low as 93.8% and the sinterability was poor.
Moreover, the strength is 1100MPa and the fracture toughness is 7.7MPa.
low as a · m ^0.5, it can be seen that it is inferior in strength and toughness. On the other hand, No. In the sintered body of the 20WC super hard matrix composite material, the theoretical density ratio is as high as 99.8% and the fracture toughness is 16.7MP since the iron group metal binding phase is as large as 28% by volume.
Although it has been improved to ^0.5 am, the hardness is 1210H
v, the specific wear amount is as high as 7.9 × 10 ⁻¹⁶ m ² / N, which indicates that the hardness and the wear resistance are inferior.

In addition, No. Since the WC-based cemented carbide based composite material No. 23 does not contain Group 4a to 6a elements,
The theoretical density ratio is as low as 94.3% and is inferior in sinterability.
Since the strength is as low as 1220 MPa, the hardness is as low as 1580 Hv, and the specific wear amount is as high as 4.5 × 10 ⁻¹⁶ m ² / N, it can be seen that the strength, hardness and wear resistance are inferior. In addition, No. 22 is a WC-based cemented carbide composite sintered body,
Although Zr, which is an element of Group 4a to 6a, is contained, its amount is as small as 0.05% by volume. Like 23,
The theoretical density ratio is as low as 89.9% and is inferior in sinterability.
Since the strength is as low as 1280 MPa and the hardness is as low as 1320 Hv, and the specific wear amount is as high as 6.6 × 10 ⁻¹⁶ m ² / N, it can be seen that the strength, hardness and wear resistance are inferior.

From Table 3, it can be seen that Nos. Included in the scope of the present invention.
In the WC-based cemented carbide composites 24 and 25,
Both have an oxidation weight increase of 600 g / m at a high temperature of 1000 ° C.
^TwoIt is clear that it shows excellent oxidation resistance.
You. On the other hand, no. 26 WC-based carbide-based composite material firing
In the sintered body, Ni was 2% by volume and the iron group metal binding phase was small.
WC that oxidizes rapidly at high temperatures exceeding 800 ° C
Insufficient coating, increased oxidation at 1000 ° C
952.5g / m^TwoLarge and inferior in oxidation resistance
I understand. In addition, No. 27 WC super hard composite material sintering
The body is Al_TwoO_ThreeOxygen diffusion in the sintered body
Is fast, oxidation proceeds rapidly, and Cr _ThreeC_TwoThe amount of
As it does not show sufficient oxidation resistance,
The oxidation weight gain at 0 ° C. is 1148.0 g / m^TwoAnd large
It can be seen that the oxidation resistance is poor.

It should be noted that the present invention is not limited to the specific embodiments described above, but may be variously modified according to the purpose and application.

[0036]

The sintered body of the cemented carbide composite material of the present invention has a
In a cemented carbide consisting of a hard phase mainly composed of: and a binder group of iron group metal, ceramic hard dispersed particles which are chemically stable and have excellent high-temperature characteristics are dispersed, and 4a to 4a excluding W By containing one or more of the Group 6a elements, the strength and hardness are improved, and a cemented carbide-based composite material having excellent wear resistance, oxidation resistance, corrosion resistance, and fracture resistance is obtained. be able to. Since the cemented carbide composite material of the present invention has the above characteristics, various tools (high-speed cutting, high-feed cutting,
Cutting tools used for heavy-duty cutting, hot rolling rolls, guide rolls, drawing rolls, dies, punches, etc., jigs and tools used for hot, warm, and cold plastic working and ductile working), wear-resistant members (Bearings, bearing balls, slide bearings, slide guides, etc.).

Continuation of the front page (72) Inventor Satoshi Iio 14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi F-term (reference) in Japan Special Ceramics Co., Ltd. FA08 FA15 FA31 GA60

Claims (5)

[Claims] 1. The sintered body contains 10 to 76% by volume of a hard phase mainly composed of tungsten carbide (WC) and 3 to 20% by volume of a metal bonding phase composed of one or more alloys of iron group metals. %, 4 to 70% by volume of ceramic hard dispersion particles, and 0.1% by volume or more of carbides in an amount of one or more of elements of Groups 4a to 6a excluding W. Carbide matrix composite sintered body. 2. The tungsten carbide-based super-hard composite material sintered body according to claim 1, wherein at least a part of the group 4a to 6a group element is dispersed in the ceramic hard dispersion particles. 3. The tungsten carbide-based ultra-hard composite material sintered body according to claim 1, wherein said hard ceramic dispersed particles are hard alumina dispersed particles. 4. The tungsten carbide based cemented carbide composite according to claim 1, wherein an intermetallic compound is present in the sintered body. 5. The sintered body has a porosity of A02 according to ASTM standard.
The tungsten carbide-based cemented carbide composite sintered body according to claim 1, wherein: