JP2003082432A - Hard material and indexable insert type cutting tip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hard material free from jointed part and having locally different properties, a cutting tip and a method for manufacturing them. SOLUTION: The hard material is constituted of a hard phase, a binding phase and inevitable impurities and integrally formed without jointed part. The quantity of the binding phase varies with the part; when the total quantity of the binding phase contained in the whole hard material is A% by weight, a difference in percent by weight between the quantity of the binding phase in a part where the quantity of the binding phase is largest and that in a part where the quantity of the binding phase is smallest is >=A×0.02. The hard material with the above constitution can be obtained by providing a gradient to at least either of temperature and atmosphere during sintering.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard material suitable for a cutting tool, a method for manufacturing the same, and a cutting edge exchange type cutting tip having a wide range of uses.

[0002]

2. Description of the Related Art Cermet alloys and cemented carbides generally used as cutting tools are required to have excellent properties such as heat crack resistance, oxidation resistance, high temperature hardness and fracture toughness. Cemented carbides and cermets used in current cutting tools have been variously devised by many researchers in order to improve heat crack resistance and fracture toughness. As a market need in recent years, in order to reduce the management cost of tools, the advent of cutting tools that can handle a wide range of work materials and cutting conditions with a single tool is desired.

Hard materials, such as cemented carbide and cermet, which are composed of a hard phase and a binder phase and which are produced by pressing powder and sintering, include not only the hard phase composition but also the hard phase in the alloy structure. The hardness and strength of the phase change depending on the particle size of the phase and the amount of the binder phase, and thus the intended use also changes. For example, it is general to use an alloy having many binder phases and high strength for intermittent cutting, and an alloy having few binder phases and high hardness when continuously cutting a high hardness work material.

Attempts have been made in the past to change the characteristics of hard materials depending on the part of the cutting tool, for example, Japanese Patent Laid-Open Publication No. 61-61.
-191380 is a technique for spraying cermet on a cemented carbide, JP-A-54-6803, JP-A-2000-144300 is a technique for sintering and joining cemented carbides having different compositions, JP-A-9-41
Japanese Patent Laid-Open No. 006 proposes a technique of molding using a plurality of slurries.

[0005]

However, each of these techniques adds a new step to the conventional manufacturing method, which causes an increase in manufacturing cost. Further, there are problems that the strength of the joint portion is insufficient and that the shape that can be manufactured is limited.

[0006] Therefore, a main object of the present invention is to provide a hard material having no joining portion and having partially different characteristics, a cutting tip and a manufacturing method thereof.

[0007]

The present invention achieves the above object by providing a gradient in at least one of temperature and atmosphere during sintering.

That is, the present inventor has conducted extensive research on cutting tips capable of handling a wide range of work materials and cutting conditions with a single tool. The inventors have invented a hard material that can change the strength of each part by changing the amount of binder phase for each part without adding a new step, and a manufacturing method thereof. In particular, it is effective to use this hard material as a cutting tip and to use it as a cutting tip having different strength for each cutting edge.

Since the cutting tip of the present invention is manufactured by using one kind of raw material, it is possible to manufacture a complicated shape without a joint. The cutting edge exchange type cutting tip made of a hard material containing a hard phase and a binder phase is generally manufactured by crushing and mixing raw material powder, press-molding and sintering the powder. Depending on the case, after that, it is processed to the target shape and target dimensional accuracy with a grindstone or the like. The present inventor has focused on this sintering process.

Conventionally, the sintering furnace has been creatively devised with the aim of making the temperature and atmosphere in the furnace uniform. On the contrary, in the present invention, by sintering in the condition that a predetermined temperature gradient and / or atmosphere gradient is provided in advance, the binder phase undergoes mass transfer along the gradient during the sintering process, and as a result, It was found that it is possible to manufacture hard materials having different amounts of binder phase for each part.

The cause of the mass transfer of the bonded phase is unknown,
It is presumed that the liquid phase appears first on the higher temperature side, and the binder phase on the lower temperature side is selectively dissolved to form a gradient. If this temperature and / or atmosphere gradient is set horizontally, a hard material having a binder phase gradient in the horizontal direction can be obtained, and this temperature and / or atmosphere gradient is set vertically. By doing so, it is possible to obtain a hard material having a gradient of the amount of binder phase in the vertical direction.
If necessary, the sintered body produced in this manner is processed with a grindstone, a brush, or the like to obtain a cutting edge-exchangeable type cutting tip of the present invention. However, if the final shape has already been obtained at the time of molding, it is not necessary to perform such processing.

From the above reasons, it is desirable that the hard material suitable for the chip of the present invention is composed of a hard phase, a binder phase and unavoidable impurities and is liquid phase sintered. At this time, assuming that the amount of the binder phase contained in the entire material is A% by weight, the difference in the weight% of the binder phase amount between the portion having the highest binder phase amount (blade edge) and the portion having the lowest binder phase amount (blade edge). Is less than A × 0.02, the effect is small. If the difference in the amount of binder phase is 0.03 or more, the effect becomes remarkable, and if it is 0.05 or more, the material properties change greatly. This difference in the amount of binder phase can be arbitrarily produced depending on the intended use.

As a concrete base material, any of the following is industrially significant. (1) Cemented Carbide Hard Phase: Tungsten Carbide Bonding Phase: One or more of Iron-based Metals, Content of 3 to 30% by Weight Balance: Inevitable Impurities

(2) Cemented carbide hard phase: a compound or solid solution phase of a transition metal of group IVa, Va, VIa of the tungsten carbide periodic table and one or more selected from carbon, nitrogen, oxygen and boron. Content is 0.1 to 50% by weight Binder phase: One or more ferrous metals, content is 3 to 30% by weight Balance: Inevitable impurities

(3) Cermet alloy hard phase: a compound or solid solution phase of a transition metal of group IVa, Va or VIa of the periodic table and one or more kinds selected from carbon, nitrogen, oxygen and boron. Content is 80-97% by weight Binder phase: One or more iron-based metals, content is 3-20% by weight Balance: Inevitable impurities

The composition range of the above cemented carbide and cermet is a range generally manufactured industrially, but even if the composition range deviates from this range, the amount of binder phase can be changed depending on the site. The effect of the invention appears. Also, the periodic table
The compound or solid solution phase of the group IVa, Va or VIa transition metal and one or more selected from carbon, nitrogen, oxygen and boron preferably has a B-1 type crystal structure.

Here, when the cemented carbide and the cermet are used as the base materials, the obtained hard material of the present invention has a different amount of binder phase depending on the site, which results in the saturation magnetization (4πσ).
, Which also changes the coercive force (Hc). As a result of various studies, in the cutting edge exchangeable tip of the present invention using a cemented carbide and cermet as a base material, the coercive force change for each site is Hc of the entire cutting edge exchangeable tip as B,
When the difference in coercive force between the cutting edge with the highest amount of binder phase and the cutting edge with the lowest amount of binder phase is B × 0.05 or less, the balance between the improvement in the strength of the cutting edge and the decrease in hardness with the increase in the amount of binder phase becomes the best. I knew that.

Of course, the present invention is also effective for materials other than cemented carbide and cermet.

Further, even if the coating layer is formed on the hard material after sintering by the chemical vapor deposition method or the physical vapor deposition method, the effect of the present invention is not lost. The coating layer is composed of at least one selected from the group consisting of carbides, nitrides, carbonitrides, boronitrides, carbonitride oxides, aluminum oxides and zirconium oxides of Group IVa, Va and VIa metals of the periodic table. Layers or layers are preferred. The material forming the coating layer may have any crystal structure, and may be amorphous.

Next, FIG. 1 is a structural schematic diagram of a sintering furnace for sintering while applying a specific temperature and / or atmosphere gradient.
As shown in FIG. These are just examples, temperature and / or
Alternatively, any device that can provide an atmosphere gradient may be used for sintering.

FIG. 1 is an example of a schematic view of a sintering furnace that applies a temperature gradient in the horizontal direction. The sintering furnace 10 has a structure in which a heater 11 and a heater 12 are arranged on the left and right sides of a support base 30 on which a sample 20 is placed, and a pair of heat insulating materials 40 sandwiches the heaters 11 and 12 from above and below. The inside of the furnace is configured so that it can be adjusted to a predetermined pressure by a vacuum pump.

By independently controlling the heater 11 and the heater 12, the sample 20 has a temperature gradient in the horizontal direction. This temperature gradient may be set from the initial stage of sintering or may be set from an arbitrary temperature, but it is desirable to give it from the beginning to the end of shrinkage of the sintered body.

FIG. 2 is a schematic view of a sintering furnace that applies a temperature gradient and / or an atmosphere gradient in the horizontal direction. This sintering furnace is also the same as the sintering furnace of FIG. 1 in that the sample is sandwiched between the heater 11 and the heater 12 from the left and right. However,
The difference lies in that an exhaust pipe 51 is arranged so as to penetrate the heat insulating material 40 and the heater 11, and a gas introduction pipe 52 is arranged so as to penetrate the heat insulating material and the heater 12.

Here, if the heater 11 and the heater 12 are independently controlled and the atmospheric gas is introduced into the furnace,
The temperature gradient and the sintering atmosphere depending on the site can be changed. If necessary, it is possible to eliminate the humidity gradient and provide only the atmosphere gradient. This temperature gradient and / or atmosphere gradient may be set from the initial stage of sintering, or may be set from an arbitrary temperature, but it is desirable to give it from the beginning to the end of shrinkage of the sintered body.

1 and 2 show a sintering furnace which gives a temperature gradient in the horizontal direction, it is also possible to give a temperature gradient in the vertical direction by installing heaters on the upper and lower surfaces.

In the cutting edge exchangeable type tip which is sintered in such a sintering furnace, the cutting edges existing in the plane parallel to the heater have the same binder phase amount. That is, the difference between the amount of binder phase of all the cutting edges existing on a specific surface and the amount of binder phase of all the cutting edges existing on another surface can be set to A × 0.02 or more. For example, in the case of a rectangular parallelepiped cutting tip having eight cutting edges, the amount of binder phase is different between the four cutting edges existing on one surface and the four cutting edges on the other surface. It is preferable that the specific surface and the other surface are the surfaces having the largest area in the chip, or the largest surface and the second largest surface.

By providing a temperature gradient and / or an atmosphere gradient by the method described above, the amount of binder phase can be inclined between any surface and another surface. Especially if not only the temperature control of the heater but also the shape of the heater is devised,
It is also possible to raise the bonding phase only in an arbitrary part, not in an arbitrary plane.

It is possible to arbitrarily control how much the amount of the binder phase is graded by the magnitude of the temperature gradient and / or the atmosphere gradient to be applied. The temperature gradient is the difference in temperature between any face of the hard material and the face facing it from 3 ° C to 1 ° C.
The temperature is preferably 00 ° C, more preferably 10 ° C to 40 ° C.
℃. The atmosphere gradient preferably has a flow rate difference of 0.1 to 20 l / min between any surface of the hard material and a surface facing the hard material, and more preferably a flow rate difference of 0.5 to 10 l / min.

The amount of the binder phase may be identified by any method such as electron microscope analysis and wet analysis. When performing wet analysis, the hard material and / or any part of the cutting tip is cut out and analyzed. In the case of an electron microscope, the analysis surface is cut and wrapped for analysis. "The part with the highest amount of binder phase" and "the part with the lowest amount of binder phase" are divided samples of the hard material by discharge wire cutting, polishing, etc. to the minimum size for Co analysis by CIS-032. Is determined by Co analysis by the method described in CIS-032. Due to error and accuracy, the lower limit weight of the divided sample is 0.1g or more,
More preferably, it is 0.2 g or more, and the upper limit weight is Co
In order to know the amount, the lighter it is, the more preferable it is, 2 g or less, more preferably 1 g or less. This divided sample is crushed, and a sample of 0.1 to 0.2 g is weighed and used as a sample for Co analysis.

In many cases, the cutting edge exchange type cutting tip is provided with a design called a chip breaker for cutting chips during cutting. In this case, it is the meaning of preventing the confusion of the cutting edge and / or the tool material that the design such that the amount of the binding phase of the cutting edge is known and the design that is expected to be used according to the amount of the binding phase are given to the press body in advance. Is industrially significant in that the potential of In particular, the above-mentioned rectangular parallelepiped exchangeable tip is generally press-molded by combining three dies (upper punch, lower punch, and die). Therefore, in the case of giving a gradient of the amount of binder phase in the vertical direction, it suffices to previously combine the punches of the designs having the best industrial efficiency with the respective amounts of binder phase and perform press molding.
That is, by using the upper punch and the lower punch to form the existing punches with different designs, (1) the existing punch can be used,
(2) There is an industrial merit that a product equipped with a chip breaker suitable for the application predicted from the amount of binder phase can be manufactured.

The hard material of the present invention and the cutting edge exchange type cutting tip of the present invention can be provided at a low cost because they do not have a joining portion having weak strength unlike the conventional method and the number of manufacturing steps does not increase. It also has industrial advantages.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. (Example 1) The raw material powders shown in Table 1 were wet-mixed with the composition shown in Table 1 for 10 hours, and then press-molded at a pressure of 1 ton / cm ² . The press-molded body was sintered in a sintering furnace having the structure shown in FIG. 1 and then ground with a diamond grindstone to obtain a SPGN190408-shaped sintered body according to JIS4122.

The content of the sintering program is as follows: heater 11 starts to heat up to 1400 ° C. at a heating rate of 6.0 ° C./min, and heater 12 starts 5 minutes after the program of heater 11 starts. It was That is, the temperature difference between the heater 11 and the heater 12 was set to 30 ° C. Heater 11
60 minutes after the temperature reached 1400 ° C., the heaters 11 and 12 were turned off at the same time.

[0034]

[Table 1]

In this way, the cutting tip 1 of the present invention is manufactured, and for comparison, the heater 11 and the heater 12 are sintered under the same program to sinter without giving a temperature gradient. A also prepared. After measuring the coercive force (HC) of these chips according to CIS-031, the intermittent cutting test and continuous cutting test were performed under the following conditions,
The flank wear amount of the cutting edge and the fracture rate of the cutting edge were examined. In the chip 1 of the present invention, the continuous cutting test was performed with the blade edge sintered adjacent to the heater 12 side, and the intermittent cutting test was performed with the blade edge sintered adjacent to the heater 11.

Continuous cutting test Work Material: SCM435 (HB = 246) Round Bar Cutting speed: 190m / min Feed: 0.27mm / rev. Notch: 2.0 mm Cutting time: 5 minutes Cutting oil: Water-soluble oil Amount of wear: The amount of wear on the flank was measured.

Intermittent cutting test Work material: SCM435 (HB = 246) Square material Cutting speed: 154m / min Feed: 0.45mm / rev. Depth of cut: 2.0mm Cutting time: 1 minute Cutting fluid: None Defect rate: 10 cutting edges The test was conducted to determine the number of defective cutting edges.

Further, as shown in FIG. 3, a sample was cut into a width of 3 mm from each of the heater 11 side and the heater 12 side, and the coercive force of the cut samples and the cobalt amount analysis by CIS-032 were performed. The heater 11 side of the chip is the part (a), and the heater 12 side is the part (a). At the time of cobalt amount analysis, an excess crushed sample not used in the analysis and a sample obtained by crushing the alloy in the unanalyzed part were thoroughly mixed and analyzed, and the value was analyzed as the cobalt amount of the present chip before cutting and the comparative chip. did. As a precaution, HC measurement and cobalt content analysis were performed without cutting the chips of the present invention and comparative chips manufactured using exactly the same raw material and method, and the values match those of the aforementioned chips of the present invention and comparative chips. I also confirmed. Table 2 shows the cutting test results and analysis results.

[0039]

[Table 2]

Here, the binding phase amount A of the entire chip of the present invention is
At 8.9wt%, the amount of bonded phase H at the site (a) with the highest amount of bonded phase
Is 9.4 wt%, and the amount of binder phase L at the site with the lowest amount of binder phase (a)
Is 8.7 wt%, the difference in the amount of binder phase is 9.4-8.7 = 0.7, which is A × 0.02 = 0.178 or more. On the contrary, the comparison chip is 9.
0-8.9 = 0.1 <0.178.

The HC of the entire chip of the present invention is 16.0, the HC of the part (a) is 16.1, and the HC of the part (b) is 15.9, so that (16.1-15.9) /16.0=0.0125, which is 0.05 or less. Has become.

From the above, the cutting edge exchange type cutting tip of the present invention is a single tip, and by selecting the cutting edge according to the cutting form, it is possible to perform continuous cutting which was not possible with the conventional homogeneous cutting tip (comparative tip of this time). It can handle a wide range of situations from cutting to interrupted cutting.

Example 2 The raw material powders shown in Table 3 were wet mixed with the same composition shown in Table 3 for 7 hours, and then 1 ton / c was obtained.
Press molding at a pressure of m ² . This press-molded body
Sintering was performed in a sintering furnace having a structure of 4. This sintering furnace consists of a heater 11 and a heater 11 placed vertically with a support stand on which the sample is placed.
12 is arranged, and the upper and lower sides of both heaters are sandwiched by a pair of heat insulating materials. The inside of the furnace is configured so that it can be adjusted to a predetermined pressure by a vacuum pump. After that, the sintered body is ground with a diamond grindstone, and by coating the surface of these sintered bodies with a TiCN film having a film thickness of 5 μm by a known chemical vapor deposition method, a cutting tip having a CNMG633 shape specified by JIS4121 is obtained. It was

The contents of the sintering program are as follows: the heater 11 starts to heat up to 1450 ° C. at a heating rate of 5.0 ° C./min at the same time, and the heater 12 starts 8 minutes after the heater 11 program starts. It was That is, the temperature difference between the heater 11 and the heater 12 was 40 ° C. Heater 11
60 minutes after the temperature reached 1450 ° C., the heaters 11 and 12 were turned off at the same time. During press forming, the chip breaker for light steel cutting (SU type manufactured by Sumitomo Electric Industries, Ltd.) is on the surface that is in contact with the support, and the chip breaker for light steel cutting (Sumitomo Electric Industries, Ltd.) is on the opposite side. Molded so that it will be UX type manufactured by Co., Ltd.).

[0045]

[Table 3]

In this way, the cutting tip 2 of the present invention is manufactured, and for comparison, the heater 11 and the heater 12 are sintered under the same program to sinter without giving a temperature gradient. B also prepared. After measuring the coercive force (HC) of these chips according to CIS-031, the intermittent cutting test and continuous cutting test were performed under the following conditions,
The flank wear amount of the cutting edge and the fracture rate of the cutting edge were examined. For the chip 2 of the present invention, the continuous cutting test was performed on the lower surface, that is, the cutting edge provided with the SU type breaker, and the intermittent cutting test was performed on the upper surface, that is, the cutting edge provided with the UX type breaker.

Continuous cutting test Work Material: SCM435 (HB = 246) Round Bar Cutting speed: 240m / min Feed: 0.20mm / rev. Notch: 1.0 mm Cutting time: 15 minutes Cutting oil: Water-soluble oil Amount of wear: The amount of wear on the flank was measured.

Intermittent cutting test Work material: SCM435 (HB = 246) Square material Cutting speed: 174m / min Feed: 0.37mm / rev. Depth of cut: 2.0mm Cutting time: 1 minute Cutting fluid: None Defect rate: 10 cutting edges The test was conducted to determine the number of defective cutting edges.

Further, the sample was divided into upper and lower parts as shown in FIG. 5, and the coercive force of the cut samples and the amount of cobalt were analyzed by CIS-032. At the time of cobalt amount analysis, an excess crushed sample not used in the analysis and a sample obtained by crushing the alloy in the unanalyzed part were thoroughly mixed and analyzed, and the value was analyzed as the cobalt amount of the present invention chip before cutting and the comparative chip. did. As a precaution, HC measurement and cobalt content analysis were performed without cutting the chips of the present invention and comparative chips manufactured using exactly the same raw material and method, and the values match those of the aforementioned chips of the present invention and comparative chips. I also confirmed. Table 4 shows the above cutting test results and analysis results.

[0050]

[Table 4]

Here, the bonding phase amount A of the entire chip of the present invention is 1
At 0.0 wt%, the amount of binder phase H at the site (d) with the highest amount of binder phase
Is 10.5 wt%, the amount of bonded phase at the site (C) with the lowest amount of bonded phase
Since L is 9.4 wt%, the difference in the amount of binder phase is 10.5-9.4 = 1.1
Therefore, A × 0.02 = 0.2 or more. Conversely, the comparison chip is 1
0.1-10.0 = 0.1 <0.2.

Further, the HC of the whole chip of the present invention is 9.6, the HC of the part (d) is 9.6, and the HC of the part (c) is 9.8, so that (9.6−9.8) /9.6≈−0.021, which is 0.05. It is below.

From the above, the cutting edge exchange type cutting tip of the present invention is a single tip, and by selecting a cutting edge according to the cutting form, it is possible to achieve a continuous cutting which was not possible with the conventional homogeneous cutting tip (this time comparison tip). It can handle a wide range of situations from cutting to interrupted cutting.

(Example 3) The raw material powders shown in Table 5 were wet mixed with the same composition shown in Table 5 for 11 hours and then 1 ton / cm.
Press-mold at a pressure of ² . Figure 2 shows this press-formed product.
Sintering was performed in a sintering furnace having the above structure to obtain a sintered body. Then, the sintered body is ground with a diamond grindstone, JIS4121
The specified cutting tip of SNGN432 shape was obtained.

The sintering program content is that the heaters 11 and B are heated to 1460 ° C. at a temperature rising rate of 4.0 ° C./min at the same time as starting, and 60 minutes after reaching 1460 ° C., the heaters 11 and 12 are turned on. I turned off the power at the same time. At this time, argon gas was continuously supplied from the gas inlet at a flow rate of 1 liter per minute.

[0056]

[Table 5]

In this way, the cutting tip 3 of the present invention was manufactured, and for comparison, the apparatus was manufactured by sintering the apparatus in FIG. 1 without introducing atmospheric gas into the furnace, that is, without applying an atmospheric gradient. Chip C is also prepared.

After measuring the coercive force (HC) of these chips according to CIS-031, an intermittent cutting test and a continuous cutting test were conducted under the following conditions to examine the flank wear amount of the cutting edge and the chipping rate of the cutting edge. In the chip 3 of the present invention, the continuous cutting test is an atmosphere gas introduction port, that is, a blade edge sintered adjacent to the heater 12 side, and the intermittent cutting test is an exhaust port, that is, a blade edge sintered adjacent to the heater 11. It was carried out in.

Continuous cutting test Work Material: SCM435 (HB = 246) Round Bar Cutting speed: 200m / min Feed: 0.30mm / rev. Notch: 1.0 mm Cutting time: 15 minutes Cutting oil: Water-soluble oil Amount of wear: The amount of wear on the flank was measured.

Intermittent cutting test Work material: SCM435 (HB = 246) Square material Cutting speed: 154m / min Feed: 0.37mm / rev. Depth of cut: 2.0mm Cutting time: 1 minute Cutting fluid: None Defect rate: 10 cutting edges The test was conducted to determine the number of defective cutting edges.

Further, as shown in FIG. 3, samples were cut from the heater 11 side and the heater 12 side with a width of 3 mm, and the coercive force of the cut samples and the cobalt amount analysis by CIS-032 and the fluorescent X-ray analysis were performed. The amount of nickel was analyzed.
Heater 11 side of chip is part (a), heater 12
The side is designated as part (a).

In the cobalt amount analysis, an excessively crushed sample not used for the analysis and a sample obtained by crushing the alloy in the unanalyzed portion were thoroughly mixed and analyzed, and the analyzed values of the chip of the present invention before cutting and the comparative chip The amount of cobalt and the amount of nickel were used. As a precaution, HC measurement and cobalt content and nickel content analysis were carried out without cutting the chips of the present invention and comparative chips manufactured by using exactly the same raw material and method, and the values were the same as those of the aforementioned chips of the present invention and comparative chips. We also confirmed that they match. Table 6 shows the cutting test results and analysis results.

[0063]

[Table 6]

Here, the binding phase amount A of the entire chip of the present invention is 1
At 4.9 wt%, the amount of binder phase H at the site (a) with the highest amount of binder phase
Is 15.6 wt%, the amount of bonded phase at the site (a) with the lowest amount of bonded phase
Since L is 14.4 wt%, the difference in the amount of binder phase is 15.6-14.4 = 1.
2, which is A × 0.02 = 0.298 or more. On the contrary, the comparison chip is 15.0-14.9 = 0.1 <0.298.

Further, the HC of the entire chip of the present invention is 12.1, the HC of the part (a) is 12.4, and the HC of the part (b) is 12.0, so (12.4-12.0) /12.1≈0.033, which is 0.05 or less. Has become.

[0066]

As described above, the hard material of the present invention and the cutting edge-exchangeable cutting tip of the present invention can be configured to have different amounts of binder phase depending on the site or the cutting edge. Therefore, a hard material that can be used for a wide range of applications can be obtained with a single material. In particular, by selecting a combination of the application and the amount of binder phase of the cutting edge, it is possible to obtain a cutting tip having both strength and wear resistance that could not be achieved in the past.

Further, unlike the prior art, since there is no joint having weak strength and the number of manufacturing steps does not increase, it has a great industrial advantage that it can be provided at low cost.

[Brief description of drawings]

FIG. 1 shows an outline of a sintering furnace used in the method of the present invention,
(A) is a plan view and (B) is a front view.

FIG. 2 shows a schematic view of a sintering furnace used in the method of the present invention,
(A) is a plan view and (B) is a front view.

FIG. 3 is an explanatory diagram showing a cut portion of a sample.

FIG. 4 shows an outline of a sintering furnace used in the method of the present invention,
(A) is a side view and (B) is a front view.

FIG. 5 is an explanatory diagram showing a cut portion of a sample.

[Explanation of symbols]

10 sintering furnace 11 heater 12 heater 20 samples 30 support 40 insulation 51 Exhaust pipe 52 Gas inlet pipe

Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C22C 29/00 C22C 29/00 Z

Claims (9)

[Claims] 1. A hard material which is composed of a hard phase, a binder phase and an unavoidable impurity and which is integrated without a bonding portion, and the binder phase amount differs depending on the site, and the total binder phase amount contained in the entire hard material. Where A is% by weight, the hard material is characterized in that the difference in the weight% of the binder phase amount between the site having the highest binder phase amount and the site having the lowest binder phase amount is A × 0.02 or more. 2. A cutting edge exchange type cutting tip which is composed of a hard phase, a binder phase and unavoidable impurities and which is integrated without a joining portion, wherein the hard phase is tungsten carbide and the binder phase is 3 to 30% by weight. If the total of the amount of binder phase contained in the entire cutting tip is A wt%, the cutting edge that has the highest amount of binder phase and the one that has the highest amount of binder phase Cutting edge exchangeable cutting tip, characterized in that the difference in the weight% of the amount of binder phase from the cutting edge having a low amount is A × 0.02 or more. 3. A cutting edge exchange type cutting tip which is composed of a hard phase, a binder phase and unavoidable impurities and is integrated without a joining portion, wherein the hard phase is made of the following two materials, and the tungsten carbide periodical law is used. Table IVa, Va, VIa 0.1 to 50% by weight of a compound or solid solution phase of a transition metal and one or more selected from carbon, nitrogen, oxygen and boron, and a binder phase of 3 to 30% by weight of an iron-based metal. If the total number of binder phases contained in the entire cutting tip is A weight%, the cutting edge with the highest binder phase content and the blade edge with the lowest binder phase content are provided. Cutting edge exchange type cutting tip, characterized in that the difference in the weight percentage of the amount of binder phase is A × 0.02 or more. 4. A cutting edge exchange type cutting tip which is composed of a hard phase, a binder phase and an unavoidable impurity and is integrated without a joint portion, wherein the hard phase is a transition metal of Group IVa, Va or VIa of the periodic table. And 80% to 97% by weight of a compound or solid solution phase of at least one selected from carbon, nitrogen, oxygen and boron, and a binding phase of at least 1% of 3 to 20% by weight of an iron-based metal. If the total amount of the binder phase contained in the entire cutting tip is A weight% with the blade tips having different phase amounts, the weight% of the binder phase amount of the blade edge with the highest binder phase amount and the blade edge with the lowest binder phase amount The cutting edge exchange type cutting tip is characterized by a difference of A × 0.02 or more. 5. When the total amount of binder phase contained in the entire cutting tip is A% by weight, the amount of binder phase of all the cutting edges existing on a specific surface and the bonding of all the cutting edges existing on another surface. The cutting edge exchangeable cutting tip according to any one of claims 2 to 4, wherein a difference in weight% from the phase amount is different by A × 0.02 or more. 6. The specific surface is a surface having the largest area of the chips, or the specific surface is a surface having the largest area of the chip and a surface having the second largest area.
Exchangeable cutting edge cutting tip. 7. When the coercive force HC of the entire cutting tip is B, the difference in coercive force (HC) between the cutting edge having the highest amount of binder phase and the cutting edge having the lowest amount of binder phase is B × 0.05 or less. 7. The cutting edge-exchangeable type cutting tip according to any one of claims 2 to 6. 8. A step of forming one kind of compounded raw material consisting of a hard phase, a binder phase and inevitable impurities into a molded body, and a step of forming a temperature gradient from one side to the other side of the molded body and sintering. A method of manufacturing a hard material, comprising: 9. A step of forming one kind of compounded raw material composed of a hard phase, a binder phase and an unavoidable impurity into a molded body, and a step of forming an atmosphere gradient from one side to the other side of the molded body and sintering. A method of manufacturing a hard material, comprising: