CN115943222A

CN115943222A - Grinding, stirring, mixing and mixing machine component

Info

Publication number: CN115943222A
Application number: CN202180044645.3A
Authority: CN
Inventors: 真岛克弥; 黑木史哉; 上野修司; 田中敬章; 皆川泰范; 渡边景太
Original assignee: Nippon Tungsten Co Ltd
Current assignee: Nippon Tungsten Co Ltd
Priority date: 2020-10-09
Filing date: 2021-07-28
Publication date: 2023-04-07
Also published as: WO2022074904A1; KR20230019161A; DE112021005360T5; JP6922110B1; JP2022063199A

Abstract

The invention provides a grinding, stirring, mixing and mixing mill component which is light, excellent in impact resistance and abrasion resistance and further has magnetism, and the components have long service life. That is, the present invention provides a member for a pulverizer, mixer, kneader, or the like, which comprises a cermet, wherein the cermet has a composition obtained by mixing, in a mass ratio of each element of Ti:20 to 45%, mo:5 to 35%, W: 6-30%, C:5 to 15%, co:10 to 50% and Co and Ni in an amount of more than 25% and not more than 50% in total, mixing the raw materials, obtaining a mixed powder, press-molding the mixed powder to obtain a compact, and sintering the compact to obtain the cermet. The cermet comprises a core phase 2 mainly composed of TiCN, a ring phase 3 mainly composed of (Ti, mo, W) (C, N) and present so as to cover the periphery of the core phase, and 3 phases of a metal phase 4, wherein the average particle diameter of a hard phase composed of the core phase and the ring phase in the cross-sectional structure observation is less than 3 μm, and no WC phase and no Mo phase are observed in the SEM observation ₂ And C phase.

Description

Grinding, stirring, mixing and mixing machine component

Technical Field

The present invention relates to a member for a pulverizer, a mixer, or a kneader, which comprises a cermet having excellent impact resistance and wear resistance.

Background

Various material design methods have been proposed for cermets having excellent impact resistance and wear resistance.

Patent document 1 discloses a method for producing a cermet having high strength even if the ratio of TiN/TiC is 3/7 to 7/3 by using a three-stage sintering method of temporary sintering in a reduced pressure nitrogen atmosphere, HIP treatment, and final heat treatment in a reduced pressure nitrogen atmosphere, thereby eliminating pores and a binder phase pool. Such carbonitride-based cermets are used for cutting tool applications such as milling.

Patent document 2 discloses the following cermets: in a conventional cermet having a 2-phase structure in which a core composed of a hard phase and a ring having a tough peripheral structure are fine structures, a third phase rich in WC having excellent toughness is formed around the core, thereby further increasing the toughness. The cermet has improved bending strength and fracture toughness without lowering wear resistance and hardness as compared with conventional cermets, and can be widely used as a tool for machine tools, not to mention, parts and members requiring wear resistance and toughness.

Patent document 3 discloses a cermet having improved impact resistance, wear resistance, and resistance to thermoplastic deformation by increasing the amount of nitride, controlling the grain size of a hard phase to be coarser, and further strengthening a binder phase. This solves the problem of shortening the life of the cutting tool due to a defect caused by thermal cracking, in which a severe thermal shock is intermittently applied.

Patent document 4 discloses a cermet for a heat conductive roller, which contains 5 to 50% of TiC and 1 to 25% of Mo ₂ C、TaC、VC、Cr ₃ C ₂ 1 or 2 or more of NbC, zrC and HfC, and Ni and Co in a total amount of 5 to 40%, wherein the average grain diameter of TiC is 1.5 to 15 μm, and the grain diameter of WC is 3 to 15 μm. The cermet utilizes coarse hard particles, and can suppress the surface cracks, which are the biggest problems in hot rolling, and improve the service life of the heat conducting roller.

Patent document 5 disclosesBy controlling the lattice constant of a bonding phase containing Ni and Co as main components

The thermal cracking resistance is improved and the life of the high-speed cutting tool is improved as follows.

In addition, in recent years, demand for lightweight high-performance resin materials has increased, and for improving the properties thereof, production of reinforced resin materials highly filled with fillers such as glass fibers and inorganic powders has increased. Accordingly, there is a problem of reduction in production efficiency due to pulverization, stirring, mixing, and severe abrasion of the kneading machine members. In a resin for precision electronic parts, metal contamination due to abrasion of members is a problem, and not only removal by magnetic separation but also improvement in suppression of abrasion of members as a mixing source is required as a fundamental measure.

Nitrided steel is often used as a member of a pulverizer, a stirrer, a mixer, and a kneader, but for applications requiring more wear resistance, it is known that alloy tool steel is suitable, and cemented carbide is suitable under more severe use conditions.

In patent document 6, the following production of a kneading disc is disclosed: by sintering and joining a plurality of disk constituting members made of a cemented carbide having higher wear resistance than conventional alloy tool steels by spark plasma sintering, grinding and cutting of a kneading disk having a complicated shape are facilitated and wear resistance is excellent.

Patent document 7 discloses a molding member made of cemented carbide, which is: by pressure sintering the carbide split body in the axial direction, the screw and the barrel can be configured without deformation even in the case of a long and thin shape, and this aspect enables continuous use for a long period of time.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 61-003852

Patent document 2: japanese laid-open patent publication No. 62-196352

Patent document 3: japanese patent laid-open publication No. 63-109139

Patent document 4: japanese laid-open patent publication No. 2-66135

Patent document 5: japanese laid-open patent publication No. 7-112313

Patent document 6: japanese patent laid-open publication No. 11-10709

Patent document 7: japanese patent laid-open publication No. 2011-88410

Non-patent document

Non-patent document 1: river end, tenmuracun and Qiande, powder and powder metallurgy, vol.29, no. 1 (1980), 30-34

Disclosure of Invention

Problems to be solved by the invention

When the cermet disclosed in patent document 1 is applied to a member of a pulverizer, a stirrer, a mixer, or a kneader, since the amount of metal is relatively small, impact absorption by elastic deformation is insufficient, and the toughness of the material itself is low, so that there is a possibility that breakage may occur by impact due to contact between members during operation.

In the cermet disclosed in patent document 2, since WC individual particles are present, hard WC particles are likely to serve as starting points for fracture, and there is a concern that the impact resistance is poor. Therefore, as described above, there is a possibility that cracking occurs due to contact between members during pulverization, stirring, mixing, and operation of the kneading machine members. Further, since a large amount of WC having a high specific gravity is contained, the weight of the member becomes heavy, and when the member is applied to a rotating device member, shaft rattling, an increase in load on a driving device, and the like may occur.

For the purpose of applying the cermet disclosed in patent document 3 to a cutting tool, the amount of the metal phase is small, and WC and Mo are present in the metal phase ₂ The individual particles of C are not usable because they are insufficient in toughness and impact resistance for use as a member of a pulverizer, stirrer, mixer or kneader.

The cermet disclosed in patent document 4 has WC coarse powder added for the purpose of suppressing thermal cracking, but in a member of a pulverizer, mixer, kneader or the like where abrasion of abrasive occurs, there is a problem that the volume reduction amount is increased and the life of the member is shortened due to the absence of the WC coarse powder.

Since the cermet disclosed in patent document 5 is supposed to be applied to a cutting tool, the cermet is not suitable for use as a member of a pulverizer, a stirrer, a mixer, or a kneader because the amount of the metal phase is small and the impact resistance and toughness are insufficient.

Since the kneading disks and the molding members disclosed in patent documents 6 and 7 use cemented carbide having high wear resistance, the life of the members can be increased. However, the conventional crushing, stirring, mixing and kneading machine is designed on the premise that a member made of a ferrous material is attached, and there is an unsolved problem that a member made of a cemented carbide is not suitable for replacement use of a member made of a ferrous material due to an increase in load on a driving device side, flexure of a rotating shaft, and the like caused by its high specific gravity.

The present invention has been made to solve the above problems, and an object thereof is to provide a grinding, stirring, mixing, and kneading machine member which is light in weight, excellent in impact resistance and abrasion resistance, and further has magnetic properties, and to extend the life of these members.

Means for solving the problems

The present invention solves the above problems by providing a cermet for a pulverizing, stirring, mixing, and kneading machine member, which is obtained by: the mass ratio of each element is Ti:20 to 45%, mo:5 to 35%, W: 6-30%, C:5 to 15%, co:10 to 50% and more than 25% and 50% or less of the total of Co and Ni, using as a raw material a powder selected from any of Ti or Ti compounds, mo or Mo compounds, W or W compounds, co or Co compounds, ni or Ni compounds, and carbon, and wet-or dry-mixing them to obtain a mixed powder; a step of obtaining a compact by press-molding the mixed powder at a pressure of 50 to 300 MPa; and sintering the compact at 1300 to 1700 ℃ in a vacuum, under a vacuum, in a reducing atmosphere, in an inert gas atmosphere, in hydrogen or in nitrogen, wherein the cermet has a core phase mainly composed of TiCN, a ring phase mainly composed of (Ti, mo, W) (C, N) and covering the periphery of the core phase, and 3 of the metal phasesPhase, hard phase composed of core phase and ring phase in the cross-sectional structure observation had an average particle diameter of less than 3 μm, and WC phase and Mo were not observed by SEM observation ₂ And C phase.

ADVANTAGEOUS EFFECTS OF INVENTION

The cermet obtained in the present invention has magnetism, light weight, and greatly improved abrasion resistance and impact resistance, and can prolong the life of the milling, stirring, mixing and kneading members which are worn severely.

Specifically, the present invention can be suitably used as a member of a pulverizing, stirring, mixing or kneading machine, for example, a screw element for a twin-screw extruder, a cylinder, a pulverizing pin of a pin mill device, a blade of a mixer/kneader, a member of a powder processing device such as a bead mill, etc.

Drawings

FIG. 1 is a schematic view showing a cross-sectional structure of a cermet used in a pulverizing, stirring, mixing and kneading machine member of the present invention.

FIG. 2 is a schematic view showing a cross-sectional structure of a cermet having a relatively large number of phases including Mo and W in a toroidal phase, which is used in a pulverizing, stirring, mixing, and kneading member of the present invention.

FIG. 3 is an SEM observation image of a cermet used in a pulverizing, stirring, mixing and kneading machine member of example 1.

Detailed Description

The pulverizing, stirring, mixing and kneading machine member of the present invention can be implemented as follows.

First, the mass ratio of each element is Ti:20 to 45%, mo:5 to 35%, W: 6-30%, C:5 to 15%, co:10 to 50% and more than 25% and 50% or less of Co and Ni in total, and a powder selected from any of Ti or Ti compounds, mo or Mo compounds, W or W compounds, co or Co compounds, ni or Ni compounds, and carbon is used as a raw material.

For example, the compound of Ti may be any of carbide, nitride, carbonitride, and composite carbonitride such as TiC, tiN, tiCN, (Ti, mo) (C, N), and (Ti, W) (C, N). The same applies to Mo, W, co and Ni.

Then, the above components are wet-mixed or dry-mixed to obtain a mixed powder, the mixed powder is press-molded under a pressure of 50 to 300MPa to obtain a compact, and the compact is sintered under a vacuum, reducing, inert gas, hydrogen or nitrogen atmosphere at 1300 to 1700 ℃ to obtain a member of a mill, stirrer, mixer or kneader containing cermet. The cermet has 3 phases of a core phase, a ring phase and a metal phase, and specific designs of the respective phases are described below. In the following description, the mass ratio of each element is the mass ratio in the raw material stage.

(design of core phase, ring phase)

By setting C to 5 to 15%, a hard phase composed of a fine core phase and a ring phase is formed with improved sinterability. When C is less than 5%, a sufficient volume of the core phase and the annular phase is not formed, and the wear resistance is lowered. On the other hand, when more than 15% of C is added, a free carbon phase is generated, and mechanical properties (strength, hardness, impact resistance) are greatly reduced.

In the case of adding N, it may be added arbitrarily within a range exceeding 0% and up to 5%. By adding N, the thickness of the annular phase tends to become small, and the abrasion resistance and impact resistance are improved. Further, by setting N to 5% or less, it is possible to suppress the remaining of pores in the alloy due to nitrogen gas generated during sintering, and to improve the mechanical properties.

Further, C: n =7:3 to 10:0. by mixing C: by setting the N ratio in this range, the favorable wettability of the metal phase and the hard phase composed of the core phase and the ring phase is maintained, and the denseness is improved.

Mo is mixed in the range of 5 to 35% and W is mixed in the range of 6 to 30%. TiCN forming the core phase has poor wettability with Co and Ni forming the metal phase, but Mo is added to the core phase ₂ C. The ring phase formed by WC can improve the wettability of the hard phase composed of the core phase and the ring phase. This improves the sinterability of the material, and improves the mechanical properties.

Further, by adding W, the wear resistance can be further improved. This is because the hard phase composed of the core phase and the ring phase is solid-solution strengthened by the W atom, and the hard phase is less likely to be broken when the abrasive wears.

When the total of Mo and W is 35% or less, no alloy of W and Co, mo and Co, or W, mo and Co is formed, and the impact resistance is further improved.

(design of metallic phase)

The total of Co and Ni is more than 25% and not more than 50%. When the amount of the metal is less than this range, the impact resistance becomes insufficient. When the amount of the metal is more than this range, the abrasion resistance is lowered, and the abrasion of the mill, the stirrer, the mixer, and the mixer member is increased.

Co is set to 10 to 50%. When Co having mechanical properties (hardness and abrasion resistance) superior to those of Ni is in this range, the mechanical properties of the members of the mill, mixer, kneader, etc. can be improved, and the life can be prolonged.

Further, cermets containing 10% or more of Co have sufficient magnetic properties required for magnetic separation. Magnetic separation is used in a mill, a mixer, or a device for detecting foreign matter in a material due to cutting of a member.

The mill, stirrer, mixer, and kneader member of the present invention can be produced by the following production method as an example.

(production method)

The method for producing the pulverizing, stirring, mixing, or kneading machine member of the present invention includes the following steps (steps).

Namely, it is: the mass ratio of each element is Ti:20 to 45%, mo:5 to 35%, W: 6-30%, C:5 to 15%, co: a step of mixing powders selected from any one of Ti or Ti compound, mo or Mo compound, W or W compound, co or Co compound, ni or Ni compound and carbon as raw materials in a wet or dry manner so that the total content of Co and Ni is more than 25% and not more than 50% to obtain a mixed powder;

pressing the mixed powder under a pressure of 50-300 MPa to obtain a pressed body; and

and sintering the pressed body at 1300-1700 ℃ in any atmosphere of vacuum, reduction, inactive gas, hydrogen or nitrogen.

In the case of wet mixing, the slurry is dried by vacuum standing drying, spray drying, or the like using a volatile solvent such as ethanol as a solvent. In this case, the particle size of the particles forming the core phase and the ring phase after the raw materials are mixed (hereinafter referred to as "particle size before sintering") is sufficiently made fine so that the average particle size of the hard phase after sintering is less than 3 μm. The particle size before firing may be 2.0 μm or less, preferably 1.5 μm or less, more preferably 1.0 μm or less, and still more preferably 0.6 μm or less. In general, when the particle size before sintering is 2.0 μm or less, the generation of coarse hard particles can be suppressed, and when the particle size before sintering is 1.5 μm or less, the technical feature of making the average particle size of the hard phase after sintering smaller than 3 μm can be easily satisfied. When the particle size is 1.0 μm or less, the average particle size of the hard phase after sintering becomes smaller, and the wear resistance is improved. Further, if it is 0.6 μm or less, sintering can be performed at a lower temperature, and further, the wear resistance can be improved.

The resulting fine particle powder is mixed with a resin component to be a molding binder, and granulated. Spray drying may also be used in granulation.

The granulated powder is press-molded at 50 to 300MPa by a press molding machine or an isostatic press. After molding, intermediate processing may be added as needed.

The sintering conditions are such that the main sintering is carried out in a vacuum or gas atmosphere at 1300 to 1700 ℃. Before the main sintering, a degreasing and pre-sintering step may be performed, or intermediate processing may be performed as needed at each stage after the degreasing and pre-sintering. The degreasing and pre-sintering steps may be performed continuously, or the degreasing and pre-sintering steps and the main sintering may be performed continuously. In the case of degreasing and presintering, the degreasing and presintering are carried out in a vacuum or gas atmosphere at 600 to 1000 ℃. Further, hot isostatic pressing (1252473in hot water press in a hot house).

Finally, the mixture is finished into a final shape by machining or electric machining, and the intended mill, mixer member is obtained.

(Structure of cermet for Member of crushing, stirring, mixing, kneading machine)

The structure of the cermet used in the present invention was confirmed by cross-sectional observation using SEM.

As schematically shown in FIG. 1, the cross-sectional structure 1 of the cermet includes a core phase 2 mainly composed of TiCN, a ring phase 3 mainly composed of (Ti, mo, W) (C, N) and covering the periphery of the

core phase

2, and 3 phases of a metal phase 4, wherein the mean grain size of a hard phase composed of the core phase and the ring phase in the cross-sectional structure observation is less than 3 μm, and the cermet does not contain a WC phase and Mo phase in principle ₂ And C phase. In the presence of WC phase and Mo ₂ In the case of the C phase, in SEM (scanning electron microscope) observation, the metal phase exists in a particle shape having a different brightness, in addition to the core phase and the ring phase. If it cannot be determined, analysis by EPMA (electron probe microanalyzer), EDX (energy dispersive X-ray analysis), XRD (X-ray diffraction) is performed to comprehensively determine the WC phase and Mo ₂ Presence or absence of phase C. In the case of irregular observation, 1 particle or less of 1 μm and 5 particles or less of 0.3 μm are observed in an observation field of 1 ten thousand times. In the present invention, the "observation by SEM" shows no WC phase and no Mo ₂ The "C phase" also includes the case where 1 μm or more of particles is 1 or less and 5 or less of particles having a particle size of 0.3 μm or more in the above-mentioned 1 ten thousand times observation field.

With the above configuration, a material having high impact resistance and high abrasion resistance can be obtained.

The cermet has the following characteristics.

(core photo)

The core phase is a hard phase containing TiCN as a main component and has high hardness.

(Ring form)

The ring phase is present so as to cover the periphery of the core phase, and contains (Ti, mo, W) (C, N) as a main component. As shown in fig. 2, the annular phase may have 2 phases of a phase having relatively large Mo and W components and a phase having relatively large Ti. When the annular phase is 2 phases, the hardness of the annular phase is increased, and the wear resistance is further improved.

(particle size)

The hard phase consisting of the core phase and the annular phase has an average particle size of less than 3 μm. The average particle diameter can be calculated from the following felman formula (formula 1) by SEM observation of the cross-sectional structure of the cermet.

[ mathematical formula 1]

d _m ＝(4/π)×(N _L /N _S ) (formula 1)

N _L ＝n _L /L (formula 2)

N _S ＝n _S S (formula 3)

In (formula 1), d _m Denotes the average particle diameter,. Pi.denotes the circumference ratio, N _L Representing the number of particles per unit length hit by an arbitrary straight line on a cross-sectional tissue, N _S Represents the number of particles contained in an arbitrary unit area, wherein n in the formula 2 _L Represents the number of particles hit by an arbitrary straight line on the cross-sectional tissue, L represents the length of the arbitrary straight line on the cross-sectional tissue, and n in the formula 3 _S The number of particles included in an arbitrary measurement area is shown, and S represents the area of an arbitrary measurement region.

Since the mechanical properties and impact resistance are improved by making the average particle diameter of the hard phase composed of the core phase and the ring phase smaller than 3 μm, it is not easily broken when an impact is applied by crushing, stirring, mixing, contact of members in the operation of a kneader, or the like. In particular, by setting the average particle size of the hard phase to 1.5 μm or less, the hardness is further improved and the wear resistance is also improved. When the average particle size of the hard phase is 3 μm or more, the unit of particle shedding at the time of abrasive wear becomes large, and therefore, the wear resistance is remarkably lowered.

(specific gravity)

The specific gravity of the pulverizing, stirring, mixing, and kneading machine member according to the present embodiment is 9 or less. Since the pulverizing, stirring, mixing, and kneading machine has been designed on the assumption that a member made of a ferrous material is attached, when the specific gravity of the member exceeds 9, the member causes the occurrence of deflection of the rotating shaft, an increase in load on the driving device side, and the like. When the specific gravity is 8 or less, the treatment equivalent to that of the steel material can be performed, and when the specific gravity is 7.5 or less, the weight of the steel material is reduced, and the degree of freedom in designing the apparatus can be increased.

The cermet having the above characteristics has high wear resistance and impact resistance as high as those of cemented carbide, but has the same specific gravity as that of a steel material and further has magnetic properties. By using this material as a member of a pulverizer, a stirrer, a mixer, or a kneader, damage due to contact between members and abrasion of the members during use can be suppressed, and the life of the members can be prolonged.

Examples

First, the raw material powders shown in example 1 of table 1 were pulverized and mixed by an attritor or a ball mill using ethanol as a solvent. The obtained slurry was dried in vacuum, and paraffin as a binder was mixed, followed by compression molding to prepare a compact.

The pressed body was presintered at 800 ℃ under an atmospheric hydrogen atmosphere, and finally subjected to main firing at 1400 ℃ under a vacuum atmosphere, thereby obtaining a cermet used for a member of a pulverizer, mixer, kneader or the like according to the present invention.

The cermet obtained in example 1 had an average particle diameter of 1.12 μm calculated according to the above-mentioned Phelman formula.

The examples 2 and the following examples and comparative examples were sintered at the lowest temperature at which the highest density was obtained in the range of 1300 to 1500 ℃. Other conditions were the same as in example 1.

In addition, in all examples and comparative examples except comparative example 6, the average particle diameter of the hard phase consisting of the core phase and the ring phase was less than 1.5. Mu.m.

Further, the constituent components of the cermet cross-sectional structure were observed by SEM observation, and as a result, mo was not observed in all of the examples ₂ Presence of C phase and WC phase. In addition, in all of the examples, a phase having a relatively large Mo component and a W component exists in the annular phase.

The deviation of the element composition ratio of the whole cermet structure from the raw material composition is large, and the determination coefficient of the component ratio of the raw material composition to the cermet after sintering is low, and thus the cermet cannot be accurately quantified. For reference, the results of quantitative analysis using EPMA and EDX for the cermet of example 1 are shown in table 3, and it was possible to confirm the deviation from the raw material composition. The reason for this is considered to be that a change in the lattice state due to the formation of a solid solution of each constituent element has an influence. As shown in non-patent document 1, it is known that it is difficult to quantify the alloy composition of the cermet material in the past study, and it is difficult to accurately quantify the alloy composition.

Thus, in the present invention, it is impossible to directly determine the object or roughly impractical in terms of its structure or characteristics, and there are so-called "impossible, impractical cases" in the present invention.

[ Table 1]

[ Table 2]

[ Table 3]

/>

Next, the mechanical properties of the produced cermet were evaluated by the following measurement methods.

* Specific gravity. Archimedes method (Standard: JIS Z8807)

* hardness-Vickers hardness test (Standard: JIS Z2244)

* Abrasion resistance rubber wheel test (Standard: ASTM G65)

* Impact resistance Charpy impact test (Standard: JIS Z2242)

* Magnetism 8230and saturation magnetization determination

The properties of the cermets in the examples of the present invention and comparative examples are shown in Table 4.

[ Table 4]

The super-hard abrasion volume (mm) ³ ) Volume of sample abraded (mm) ³ )

In all examples, the specific gravity was suppressed to 9 or less, and the wear resistance was superior to that of cemented carbide (JIS classification: V40 equivalent material), and excellent properties were exhibited. In addition, the impact resistance of the ceramic material is 6J/cm which is difficult to realize with the conventional cermet ² As described above.

Examples 2 and 6 showed particularly high abrasion resistance compared to example 1.

In example 2, the addition amount of Mo was large, and further, the hardness was improved by adding W in the total, and the wear resistance was high although the amount was the same as that of the metal in example 1.

In example 6, although the Charpy impact value was less than 10J/cm ² However, the wear resistance is more than 200% as compared with that of cemented carbide (JIS classification: V40 equivalent material). This is an example of the extremely high wear resistance exhibited by suppressing the amount of metal to a minimum required.

Comparative example 1 showed a very high value for wear resistance, with a larger amount of Mo added compared to the present invention. However, since the charpy impact value is low and there is a possibility of breakage, it cannot be used as a member of a pulverizer, a stirrer, a mixer, or a kneader.

In comparative example 2, since the amount of W added was excessive, a WC phase was formed, and the wear resistance was significantly reduced.

In comparative examples 3 and 7, only Ni was used as the metal phase. The sample showed low values in hardness, wear resistance and magnetic properties because the metal phase was only Ni, although the amounts of Mo, W and metal phase were in the range. It can be said that Co addition is necessary for the expression of magnetic properties.

In the case where the addition amounts of Mo and W were small as in comparative example 4, the wear resistance showed a low value.

In comparative example 5, the metal phase (total of Co and Ni) was 24% and was less than the lower limit of the present invention. Similar to general cermets mainly used for tool applications, the wear resistance is high, but the fracture toughness, the breaking strength, and the charpy impact value are low.

Comparative example 6 is a sample prepared with the same composition of raw materials as in example 1, and without pulverization at the time of mixing. After sintering, the hard phase consisting of the core phase and the ring phase has an average particle size of more than 3 μm, and thus the hardness and impact resistance are lowered.

In comparative examples 8 to 10, although the amount of the metal phase is within the range, the amount of Co having high mechanical properties such as hardness and wear resistance is insufficient, and therefore the wear resistance is lowered. With respect to magnetic properties, it also shows lower values than the superhard material.

Fig. 3 shows an SEM observation image of the cermet of example 1. The darkest colored portion is the core phase, the darker colored portion is the ring phase, and the lightest colored portion is the metal phase.

Description of the reference numerals

1. Cross-sectional structure of cermet

2. Core phase

3. Annular phase

4. Metallic phase

5 relatively more phases of Mo and W.

Claims

1. A mill, mixer, mixing, mill member comprising a cermet, wherein the cermet is obtained by:

the mass ratio of each element is Ti:20 to 45%, mo:5 to 35%, W: 6-30%, C:5 to 15%, co: a step of mixing powders selected from any one of Ti or Ti compound, mo or Mo compound, W or W compound, co or Co compound, ni or Ni compound and carbon as raw materials in a wet or dry manner so that the total content of Co and Ni is more than 25% and not more than 50% to obtain a mixed powder;

a step of obtaining a compact by press-molding the mixed powder at a pressure of 50 to 300 MPa; and

sintering the pressed body at 1300-1700 ℃ in any atmosphere of vacuum, reduction, inactive gas, hydrogen or nitrogen,

the cermet comprises a core phase mainly composed of TiCN, a ring phase mainly composed of (Ti, mo, W) (C, N) and covering the periphery of the core phase, and 3 phases of a metal phase,

the hard phase composed of the core phase and the ring phase has an average particle diameter of less than 3 μm in the cross-sectional structure observation,

by SEM observation, no WC phase and Mo were observed ₂ And (5) phase C.

2. The member for a pulverizer, mixer, or kneader according to claim 1, wherein the mass ratio of N in the raw material is more than 0 and 5% or less.

3. The cermet-containing pulverizing, stirring, mixing, and kneading machine member according to claim 1 or 2, wherein the mass ratio of C to N in the raw material is C: n =7:3 to 10:0.

4. the cermet-containing pulverizing, stirring, mixing, and kneading member according to any one of claims 1 to 3, wherein the annular phase has 2 phases of a phase relatively rich in Mo and W and a phase relatively rich in Ti.