JPH02243735A - hard alloy - Google Patents

Abstract

PURPOSE:To improve the hardness and toughness of the hard alloy by laying >=80% of specified elements of Ti, W, Mo, V, Nb, Ta, Ni and Co in the state of carbide, nitride or the like. CONSTITUTION:The hard alloy has the compsn. constituted of, by weight, 24 to 45% Ti, 4 to 28% W, 2 to 15% Mo, 0.1 to 2.5% V, 2 to 20% Nb, 2 to 20% Ta, 5.7 to 37.9% Ni and 7.1 to 39.3% Co and in which >=80atomic % of these elements is constituted of carbide, nitride and/or carbonitride. Then, in the above respective elements, 4 to 23% Nb+Ta, 0.9 to 3.5 Ta/Nb, 20 to 45% Ni + Co and 0.4 to 1.8 Ni/Co are regulated. Furthermore, 0.3 to 0.6 N/(C+N) and 0.8 to 1 (C+N)/(the above metals excluding Ni and Co) are regulated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new hard alloy, and more specifically, it has high hardness and excellent toughness, and can be processed into cutting tools such as drills and end mills that require particularly sharp edge angles. The present invention relates to a high-toughness superhard alloy based on titanium carbides, nitrides and/or carbonitrides.

Hard alloys based on titanium carbides, nitrides and/or carbonitrides (hereinafter abbreviated as TiC-based alloys for simplicity) are lighter and harder than conventional WC-based hard alloys. It has excellent oxidation resistance and has little chemical affinity with other metals, so it is only used in some parts, such as in cutting tools.

However, TiC-based alloys generally have poor toughness and poor secondary workability, such as sharp cutting edges with small cutting edge angles, so they are only used for tools with relatively large cutting edge angles, such as bits. There were great difficulties in using it with small drills, especially small, thin drills. TiC
In order to improve the lack of toughness of the base alloy, MOlW −, N b −, Ta SCr SV have been added to the TiC base alloy.
It has often been proposed to add one or more carbides or nitrides of metals such as
Publication No. 6, Publication No. 55-40098, Publication No. 5B-323
See Publication No. 84 and Publication No. 56-32386, etc.].

These conventionally proposed TiC-based alloys can improve the lack of toughness to some extent, but the toughness is not sufficiently high to be sufficiently satisfactory, and it is difficult to process them into cutting tools with sharp edges, such as drills. Furthermore, it is difficult to process drills with small diameter and high accuracy, and even if they can be processed, they will break or become chipped within a short period of time when used for practical purposes. It was still insufficient as a cutting tool. Furthermore, it was discovered that the tools obtained by the present invention, especially drills and end mills, are not only suitable for machining hard metals, but also have remarkable effects on machining Aff and Cu. . It has been discovered that this tendency is particularly remarkable when used as a tool for a recently developed high-speed processing machine of 230,000 to 250,000 revolutions per minute.

The present inventors have developed a high-toughness TiC that eliminates the above-mentioned drawbacks.
As a result of intensive research to develop a base alloy, the present invention was completed.

Thus, according to the invention, T i, WSMo.

Contains each element of V, Nb, Ta, Ni, Co%C and N as essential components; TilW, Mo5V.

At least 80 atomic % of the sum of Nb and Ta is carbide;
Exists in the state of nitride and/or carbonitride; the content of each of the above elements is T based on the weight of the hard alloy.
124-45%, W4-28%, Mo2-15%-1V
O, 1-2.5%, Nb 2-20%, Ta 2-20%,
Ni is 5.7 to 37.9% and Co is 7.1 to 39.3%, and the total content of Nb and Ta (Nb + Ta) is 4.
~23% and the weight ratio of Ta/Nb is 0.9
~3.5; the sum of N1 and Co (Ni+
Co) content is 20 to 45% and N i /
The weight ratio of Co is within the range of 0.4 to 18: and the weight ratio of N atoms/(C atoms and N atoms) is within the range of 0.30 to 0.60; total amount of atoms)
A hard alloy is provided, wherein the atomic ratio of /(total amount of the above metal atoms excluding Ni and Co) is within the range of 0.8 to 1.0.

The hard alloy of the present invention includes Ti, W, Mo, V, Nb, Ta
, Ni, Co, C, and N as essential components, and the content ratios of these constituent elements are shown in the table below in terms of metals based on the weight of the final hard alloy. It can be within the range. However, the value in parentheses indicates the preferred range.

Metal component content ratio (%) T1
24-45 (28-40, especially 30-3 WM.

■ Nb Ta (N b + Ta) Ta / N b 4 to 28 (6 to 25, especially 1O to 20) 2 to 1 5 (3 to 2, especially 5 to 8) 0.1 to 2.5 ( 0°2-2.0, especially 0°3-l, 0) 2-20 (3-l 7, especially 5-15) 2-20 (3-17, especially 5-15) 4-23 (7- 20, especially lO~17) 0.9~3.5 (1°0~2.5, especially 1.2~2.0) 5.7~37.9 (7°0~30, especially 8°0 ~20) Co7. l-3
9-3 (8°0-35, especially 9°0-20) (N i +Go) 20-45 (20
-35, especially 20-3 N i/Co O, 4-1.
8 (0.6 to 1.5, especially 0.8 to 1.2) Also, among the above constituent elements, Ti%WSMo, ■, Nb
and most of Ta, i.e., at least 80 atomic %, preferably 85,000 atomic % or more, especially 90 atomic % or more of the total of these metal elements, are present in the hard alloy in the form of carbides, nitrides, and/or carbonitrides. It is desirable that Nb be present substantially in a carbide state and Ta be substantially present in a nitride state.

It is important that the respective amounts of C atoms and N atoms derived from carbides, nitrides and/or carbonitrides in the hard alloy of the present invention are balanced with each other, and =7 N atoms/(C atoms +N atoms) weight ratio is 0.30 to 0.
Should be in the range of 60. Outside this range, it becomes difficult to obtain an alloy with high toughness, which is the object of the present invention. Therefore, the preferred range of the weight ratio of NJF atoms/(C atoms + N atoms) is 0.33 to 0.50, more preferably 0.35 to 0.45. Therefore, the carbides, nitrides and/or carbonitrides of the metal elements constituting the hard alloy of the present invention are selected such that the weight ratio of Ng atoms/(C atoms + N atoms) falls within the above range. It is important to control the combination.

Furthermore, in the hard alloy of the present invention, the balance between the total amount of C atoms and N atoms and the total amount of metal atoms excluding N, i, and Co is also important, and (total amount of C atoms and N atoms) /
The atomic ratio of (total amount of metal atoms excluding N1 and Co) is within the range of 0.8 to 1.0, preferably 0.82 to 0.9
8, preferably within the range of 0.85 to 0.96; if the atomic ratio deviates from the above range, it is generally difficult to obtain a high toughness alloy.

In addition to the above-mentioned metal components, the hard alloy of the present invention may contain small amounts of Cr, Fe, etc. as unavoidable impurities that are brought into the alloy along with the manufacturing raw materials without any problem.

The hard alloy of the present invention described above generally uses T r s W s Mo 1V s N b as a starting material.
The carbides, nitrides and/or carbonitrides of the respective metal components of Ta and Ta, as well as the Ni and Co metals, are used in the composition proportions desired for the final alloy product and are subjected to compounding, grinding, mixing steps and drying in a manner known per se. It can be manufactured by subjecting it to a process, a molding process, a sintering process, etc.

However, some of the metal components Ti, W, Mo, V, Nb and Ta can also be used in the form of elemental metals, in which case the amount of elemental metals is 20% of the total of these metal components.
preferably less than 15 atom %, especially l
It should be less than O atomic %. Furthermore, if there is a possibility that decarburization or denitrification may occur during the sintering process, it is desirable to further reduce or not use the metal component added as a single metal.

Among the above metal components, it is preferable to use at least a part of MO in the form of an elemental metal, since it is possible to produce a hard alloy with particularly excellent physical properties.

Particularly suitable starting materials for producing the hard alloy of the present invention are therefore Ti, W, Mo, V, and Nb.

Each element of Ta, Ni, Co5C, and N is contained as an essential component in the above ratio, and in this case, T1, WlVlN
Each of the metal components b and Ta substantially exists in the state of carbide, nitride and/or carbonitride, and Mo is present at least partially in the form of an elemental metal and the remainder in the form of carbide, nitride and/or carbonitride. It is a raw powder mixture in which Ni and Co exist substantially as elemental metals, and in particular, N
Conveniently, b is used substantially in the carbide state and ta is used substantially in the nitride state.

First, in the blending step, the above starting materials are blended with a binder and a dispersion medium. Examples of binders include camphor, paraffin, liquid paraffin, and polymer compounds (e.g., polyvinyl butyral, acrylic esters, etc.), and examples of dispersion media include methyl alcohol, ethyl alcohol, acetone, toluene, xylene, and methyl acetate. This includes organic solvents such as.

The blending amount of the binder and dispersion medium is usually 20 to 70% by weight, preferably 4% by weight, based on the starting materials.
A suitable range is 0 to 60% by weight.

The above formulation is then ground and mixed. This pulverization and mixing can be carried out in the same way as is normally done using pulverization and mixing equipment such as ball mills, attritors, and vibrating mills. It is desirable to do so.

The homogeneous dispersed formulation thus obtained is then dried to remove the dispersion medium. Drying can be carried out according to a conventional method using a dryer such as a spray dryer or a Herschel mixer vacuum dryer, and it is preferable to dry the dispersion medium until the content of the dispersion medium becomes about 0.01% by weight or less. .

For example, when drying is carried out in a vacuum dryer, the drying conditions include: temperature: 10 to 80°C, preferably 30°C.
~60℃, degree of vacuum: lO-' ~ lOmmHg % time:
Examples include 0.1 to 3 hours.

The thus dried dispersion mixture is then molded by a molding machine into a molded article having a shape corresponding to the desired use.

As the molding machine, a pressure molding machine such as a rubber press machine or a powder press machine is mainly used, but depending on the case, an extrusion molding machine or an injection molding machine can also be used. When molding is performed by extrusion molding or injection molding, a plasticizer, a solvent, etc. may be added as appropriate in order to improve the fluidity of the compound. When molding with the above-mentioned pressure molding machine, the molding pressure varies depending on the compounding composition, etc., but is generally 0.5~
2. Ot/cm'', preferably within the range of 1 to 1.5 t/cm'' is considered appropriate. Others, edited by Hisashi Suzuki [Cemented Carbide and Sintered Hard Materials □Basics and Applications-J, pp. 309-372 (
(February 20, 1986, published by Maruzen Co., Ltd.); Edited by Ceramics Editorial Committee Lecture Subcommittee [Ceramics Manufacturing Process □ Powder Adjustment and Forming □] pp. 214-219 (first edition in IO, 1988, Japan Incorporated Association) (Published by Ceramics Association); Hiroshi Motoki, “Ceramics Manufacturing Process ■” 239-24
The method described in the literature such as 1 page (1st edition, 10/10/1978, published by Gihodo Publishing Co., Ltd.) can also be applied.

The molded product obtained as described above is fired in vacuum or in an inert gas atmosphere. The degree of vacuum that can be applied at that time is generally in the range of 10-2 to 10-'mmHg, preferably in the range of 10-2 to 10-'mmHg, and the inert gas is, for example, argon. , helium, nitrogen, etc.

The sintering conditions can be varied over a wide range depending on the raw material composition, the shape of the molded product, the molding conditions, etc., but it is desirable to raise the temperature after almost completely removing organic matter at a relatively low temperature. Approximately 1200 to 1700
°C1 is particularly suitable within the range of about 1300 to about 1600 °C, and the firing time is approximately 0.1 to 3 hours, especially 0.1 to 3 hours.
About 5 to 1 hour is sufficient.

By firing as described above, the desired hard alloy of the present invention can be obtained. This hard alloy can be made into a final product suitable for each use by cutting, polishing, and finishing it into a shape suitable for each use using a diamond grindstone or the like.

For example, the hard alloy provided by the present invention can be suitably used as a material for cutting tools, particularly cutting tools that require high hardness and toughness.

Conventionally, cutting tools made of TiC-based alloys have poor toughness, although they have excellent cutting properties as described above, and are therefore only used as part of cutting tools. Also,
As a method of utilizing the cutting properties of TiC-based alloys while compensating for their low toughness, many proposals have been made to coat the surfaces of cutting tools with high toughness (for example, Japanese Patent Publication No. 61
~ 51034, JP 60-162782, JP 61-96072, JP 61-231175, JP 61-247673, JP 62-4457
2 and 62-93376, etc.).

However, a blade, especially a cutting tool, having a sharp edge angle made of a TiC-based alloy has not yet been proposed.

In this specification, "cutting tool" refers to the Japanese Standards Association,
Published on April 12, 1988 (1st edition, 1st printing) - Cutting tools listed in the JIS Handbook Tools are included, specifically, cutting tools, drills, milling cutters, reamers, gear cutting tools, broaches, and thread processing. Examples include tools, hacksaws and their frames, mechanical cutters, etc., and preferably cutting tools, drills, and milling cutters. A cutting tool is a tool that has a cutting edge at the end of the shank or body, and is used in inns, boring machines, planing machines, shaping machines, standing milling machines, etc. Depending on the structure of the tool, it is a tool that has a cutting edge. There are cutting tools, welding tools, brazing tools, clamp tools, throw-away tools, insertion tools, assembly tools, etc., but the hard alloy of the present invention is especially suitable for peeling tools, edge tools, clamp tools, and indexable tools. Particularly suitable for processing.

A drill is a tool that has a cutting edge at the tip and a groove for discharging chips in the body, and is mainly used for drilling holes. There are shape drills, core drills, shell drills, center hole drills, square hole drills, countersunk drills, target drills, gun drills, spade drills, etc., but the hard alloy of the present invention is particularly advantageous for luma type drills, core drills, and spade drills. It can be used for.

In addition, 7 rice (milling cutter)
Also called a milling cutter, it is a rotary cutting tool that has cutting edges on its outer circumferential surface, end surface, or side surface, and is used for milling machines, but its types vary depending on its function or use, such as bore type milling cutters and shank type milling cutters. There is a type milling cutter. Examples of bore type mills include flat mills, slab cutters, side mills, single-edged side mills, combination side mills, face mills, shell end mills, groove mills, flush ref mills, metal saws, cold saws, segment saws, angle mills, single-sided mills, and side mills. Conformal milling cutter, conformal milling cutter, second cut milling cutter, white round milling cutter, outside size 7 milling cutter, single bevel milling cutter, double bevel milling cutter, involute milling cutter, sprocket milling cutter, spline milling cutter, serration plying cutter, thread milling cutter, general shape milling cutter, etc. However, the hard alloy of the present invention is particularly suitable for use in flat milling cutters and shell end mills. On the other hand, shank type milling cutters include, for example, endomino-single-edged end mills, double-edged end mills,
Three-flute end mill, multi-blade end mill, double-headed end mill,
Tapered blade end mill, pole end mill, taper pole end mill, radius end mill, square end mill, full-form end mill, strong helical blade end mill, semi-finishing end mill, rough cutting end mill, keyway end mill, tooth cutting end mill, countersunk refmilling, flat Examples include screw sinking milling cutter, countersunk machine screw sinking 7 milling cutter, hexagon socket bolt sinking milling cutter, chamfering milling cutter, gear chamfering milling cutter, dovetail groove milling cutter, Christmas power vine cutter, T-groove milling cutter, half-moon key groove milling cutter, and hollow mill. The hard alloy of the present invention is particularly useful when used as a constituent material of, for example, an endomino end mill, a single-blade end mill, a three-blade end mill, a multi-blade end mill, a ball end mill, a square end mill, a strong helical end mill, etc. Demonstrates excellent performance.

As mentioned above, the hard alloy of the present invention has both high hardness and excellent toughness, so if the hard alloy of the present invention is used, the cutting edge angle will be 40 to 170 degrees, preferably 45 to 170 degrees. It has the excellent feature that it can be easily processed into cutting tools having a sharp cutting edge angle of 90 degrees, more preferably 50 to 70 degrees. Here, the "edge angle" of a cutting tool refers to the edge angle of the leading edge consisting of the rake face and the flank face [For example, in the drill shown in attached Fig. 2, 90 degrees - P degrees (1-stage relief angle) is the cutting edge angle].

Moreover, the hard alloy of the present invention can also be processed into blades other than cutting tools. Cutting tools other than cutting tools include the cutting tools listed in "Blue Books, Dictionary of Cutlery Trivia, Illustrated Guide to All about Cutlery", written by Hashimoto Hidefumi, August 20, 1986, 1st printing, published by Kodansha Co., Ltd. Specific examples include knives of the Kanna family, knife family, saw family, scissors family, file family, and whetstone family, and knives for cutting soil. The knives of the Kanna tribe are knives that have the function of making straight cuts, such as planes, axes, chisels, machetes, razors, chisels, and pencil sharpeners. The hard alloy of the present invention can be suitably used for. In addition, knives of the knife family are knives that have the function of cutting by applying pulling and pushing, such as kitchen knives, rotary knives, knives, sickles, and cutters. Hard alloys can be used to advantage. Sawtooth knives are knives that have the function of cutting with a large number of rows of teeth.For example,
Examples include saws, circular saws, serrated knives, chainsaws, etc., and preferably serrated knives. Scissor-family cutlery is a cutter with the function of being able to clip with a blade, and the hard alloy of the present invention can be used, for example, with scissors, clippers, razors, lawn mowers, shears, punches, pliers, nail clippers, etc.
It is suitable for wire cutting, cutting, etc., and preferably as a material for at least the blade portion of scissors, razors, and pliers. A knife of the rasp tribe is a knife with sharp blades arranged in a row, and specifically includes a file, a grater, a claw file, a suribachi, a large file, a knife sharpener, and a horsetail. The hard alloy of the present invention can be advantageously used in files and knife sharpeners. The grindstone family of cutlery is a cutter made of hard particles, and the hard alloy of the present invention can be applied to, for example, sandpaper, grinders, fiber cleaners, metal scrubbers, etc., and preferably to grinders.

Soil-cutting knives are knives that have the function of cutting soil, sand, and rocks, and are used for agriculture, gardening, civil engineering, and mining.Specifically, they include the blades of hoes, shovels, pickaxes, bulldozers, etc. Examples include rock drilling machines, and the hard alloy of the present invention exhibits particularly excellent performance in rock drilling machines.

As mentioned above, the hard alloy of the present invention has high toughness in addition to high hardness, so it can be processed into blades other than cutting tools as described above, compared to conventional hard alloys. It has unique features that I didn't have before. However, if the hard alloy of the present invention is used, the cutting edge angle will be 10 to 40 degrees,
Preferably 12 to 35 degrees, more preferably 15 to 30 degrees
It can be processed into blades other than cutting tools that have sharp cutting edges. Here, the "blade angle" 7 for blades other than cutting tools refers to the angle of the leading edge consisting of the rake face and flank face, and specifically, for example, the angle shown by θ in the cutter shown in attached Figure 4. be.

As stated above, the hard alloy of the present invention can be processed into blades with sharp edges, and the blades using the hard alloy of the present invention have extremely little chipping of the cutting edge and very little wear on the cutting edge. It has various excellent advantages, such as being small in size and hardly welding with metal during use.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Examples 1 to 21 and Comparative Examples 1 to 9 A. Sintered bodies of Tic and TiN with an average particle size of lμ (T i C / T i N: 50 / 50,
(hereinafter referred to as T1CN), 2μ WC powder, 3μ Mo
2C and Mo powder, 2 to 3μ VC powder, 2 to 3μ NbC and NbN powder, 1 to 2p TaC and TaN powder, 4μ N1 powder and 2μ Co powder were each blended as shown in Table 1, Furthermore, for these powders,
Ethyl alcohol 50% by weight, polyvinyl butyral 2
Dioctyl phthalate (DOP) as weight% and plasticizer
)1% by weight were added to each, and the mixture was ground and mixed in a stainless steel ball mill for 48 hours. However, only T1CN of hard alloy No. 20 (Example-20) in Table-1, Ti
C/T i N was set to 70/30.

Next, the mixture obtained by drying under reduced pressure was pressure-molded at 1 Ton/cm2 using a rubber press machine. This molded body was heated at 300 to 500°C for 1 hour, vacuum degree 10-2
Depyrolysis under mmHg conditions and further 1360-1500
°C for 1 hour under a vacuum of 10-3 mmHg to prepare a rod-shaped hard alloy (61 mm x 30 mm).

B. Evaluation of hard alloys Table 2 shows the toughness and hardness of the obtained alloy.

The physical properties were measured as follows.

(1) Measurement of toughness Three-point bending strength measurement according to JIS B-4104.

(2) Measurement of hardness Measured using Takashi Micro Hardness Meter No. 36739 manufactured by Takashi Seisakusho Co., Ltd.

As is clear from Table 2, the hard alloy of the present invention has extremely high toughness despite its high hardness.

Table 2 (Part 2) (See Figure 2). The condition of the cutting edge of the obtained drill was observed and the results are shown in Table 4.

Table 3 (Unit: twice) 'Examples 22 to 63 and Comparative Examples 1O to 27 (Preparation and evaluation of cutting tools and blades) (C-1) Straight shank drill Hard alloys obtained in the above Examples and Comparative Examples was polished into a cylindrical body (5 mm x 60 mm) using a diamond polishing machine, and straight shank drills A and B were prepared as shown in Table 3. was selected and subjected to a drilling test using a drill under the cutting conditions shown in Table 5, and the results are also shown in Table 4.

The evaluation criteria for the test are as shown in Table-6.

As is clear from Table 4, the drill machined from the hard alloy of the present invention has a sharp cutter (hereinafter referred to as cutter B) without any chipping of the cutting edge even when the cutting edge angle is 74 degrees or 65 degrees. ) (see Figure 3.4 for details).

A 150μ thick polyvinyl chloride film containing 8% calcium carbonate and 5% titanium oxide was selected as the material to be cut, and the line speed of this film was 5m/m.
In, and a cutting test was conducted using the above cutter for 6000 m.

After the cutting test, the degree of wear on the cutting edge of the cutter and the state of chipping of the blade were investigated, and the results are shown in Table 7. The evaluation items and evaluation criteria are shown in Table 8.

It turns out that it can be manufactured. On the other hand, drills machined from Ti-based alloys with compositions other than those of the present invention suffer from chipping of the cutting edge, making them unsuitable for practical use.Furthermore, when a cutting test is performed on drills in which no chipping was found, The cutting edge was severely damaged or the metal to be cut was significantly welded, so it could not be used for practical purposes. On the other hand,
In the drill using the hard alloy of the present invention, no chipping of the cutting edge or welding to the metal to be cut was observed even after the cutting test. From this, it can be seen that the drill made of the hard alloy of the present invention is an extremely excellent cutting tool.

The same holds true for the end mill, and the end mill made of the hard alloy of the present invention has no chipping of the cutting edge and almost no welding to the metal to be cut, proving that it is an excellent cutting tool.

(C-2) Cutting tool (cutter) A cutter with a cutting edge angle of 16 degrees (hereinafter referred to as cutter A) and a cutting edge angle 24 Table-8 Table-7 clearly show that the hard alloys prepared in the above Examples and Comparative Examples were used with a diamond grindstone. As mentioned above, the cutter made of the hard alloy of the present invention was able to be finished sharply with both the edge angle of 16 degrees and 24 degrees, but most of the cutters of comparative examples machined from alloys with compositions other than the present invention. The cutting edge was severely damaged and it was not possible to make it sharp.

Among the cutters of the comparative example, even those that could be sharpened showed chipping or abrasion of the cutting edge when a cutting test was conducted, and none of them could be used for practical purposes.

On the other hand, the cutter according to the present invention showed no chipping at all after the cutting test, =37, and had extremely little wear on the cutting edge, proving that it is a very useful knife in practice.

In addition, it has been revealed that razors made of the hard alloy of the present invention have no chipping of the cutting edge and extremely little wear on the cutting edge.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a side view of a straight shank drill, in which H indicates torsion capacity and A indicates tip angle (135 degrees). FIG. 2 is an enlarged view of the cutting edge portion of the straight shank drill shown in FIG. 1. In the figure, P indicates the first-stage clearance angle, S indicates the second-stage clearance angle, and (90-P) is the cutting edge angle. FIG. 3 is a side view of the tip of the cutter. FIG. 4 is a plan view of the cutting edge of the cutter shown in FIG.
In the figure, θ indicates the blade edge angle. Procedural amendment (sealing) Yoshiki, Commissioner of the Japan Patent Office 1) Takeshi Moon 1, Indication of the case 1999 Patent Application No. 65597 2, Name of the invention Hard alloy 3, Person making the amendment Relationship to the case Name of the patent applicant ( 459) Nippon Carbide Industries Co., Ltd. 4.
Director 〒107 The column for detailed explanation of the invention in the specification is corrected as follows. (1) On page 3, line 15 of the specification, the phrase "based on conventional WC" is corrected to "based on conventional WC." (2) On page 5, line 5 of the same article, “23-25 recently developed
``10,000 revolutions per minute'' should be corrected to ``recently developed 30,000 to 80,000 revolutions per minute.'' , "R and Ta are present in the hard alloy of the present invention" is corrected. (5) On page 34, line 4, it says “not even”.
"It's not a thing," he corrected. that's all

Claims (1)

[Claims] 1. Ti, W, Mo, V, Nb, Ta, Ni, Co, C
and N as essential components; Ti, W, M
At least 80 atomic percent of the total of O, V, Nb and Ta is present in the form of carbides, nitrides and/or carbonitrides; the content of each of the above elements is Ti24-45, respectively, based on the weight of the hard alloy. %, W4~28%, Mo2~15%
, V0.1-2.5%, Nb2-20%, Ta2-20
%, Ni5.7-37.9% and Co7.1-39.3
%; the total content of Nb and Ta (Nb+Ta) is 4 to 23%, and the weight ratio of Ta/Nb is 0.9.
~3.5; the sum of Ni and Co (Ni+
Co) content is 20 to 45% and Ni/Co
The weight ratio of N atoms/(C atoms + N atoms) is within the range of 0.4 to 1.8; and the weight ratio of N atoms/(C atoms + N atoms) is 0.30 to 0.60.
and (total amount of C atoms and N atoms)/(N
The atomic ratio of the total amount of the above metal atoms excluding i and Co is 0
．． A hard alloy characterized in that the hardness is within the range of 8 to 1.0. 2. Nb exists substantially in the form of Nb carbide, and Ta
2. The hard alloy according to claim 1, wherein Ta is present substantially in the form of Ta nitride. 3. A cutter made of the hard alloy according to claim 1. 4. A cutting tool made of the hard alloy according to claim 1. 5. The cutting tool according to claim 4, wherein the cutting edge angle is 40 to 170 degrees. 6. The cutting tool according to claim 5, which is a drill or an end mill. 7. Ti, W, Mo, V, Nb, Ta, Ni, Co, C
and N as essential components in the proportions set forth in claim 1, in which each metal component of Ti, W, V, Nb, and Ta is substantially a carbide, nitride, and/or carbonitride. A raw material powder mixture in which at least a part of Mo exists as an elemental metal and the remainder exists as a carbide, nitride and/or carbonitride, and Ni and Co exist substantially as an elemental metal. Claim 1 characterized in that the method is fired.
Method of manufacturing the hard alloy described. 8. The method according to claim 7, wherein the raw powder mixture contains Nb substantially in a carbide state and Ta substantially in a nitride state.