JP3146803B2 - Method for producing cubic boron nitride based ultra-high pressure sintered material with excellent wear resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cubic boron nitride (hereinafter referred to as "CBN") which has more excellent wear resistance and is particularly suitable for use as a high-speed cutting tool requiring these characteristics.
) Based ultra-high pressure sintering materials.

[0002]

2. Description of the Related Art Conventionally, as described in, for example, Japanese Patent Publication No. 61-43312, in terms of volume% (% indicates volume%).
One, two or more of carbides, nitrides and carbonitrides of Ti, Zr and Hf (hereinafter referred to as metal carbonitrides): 10 to 60% as a bonding phase forming component, and oxidation as a bonding phase forming component Aluminum (hereinafter indicated as Al ₂ O ₃ )
And one or two of zirconium oxide: 0.1
CB as a dispersed phase forming component
CBN-based ultra-high pressure sintering materials having a composition of N are known, and these CBN-based ultra-high pressure sintering materials may be used as cutting tools for cutting hardened steel such as surface hardened steel. Are known.

[0003]

On the other hand, in recent years, the performance of cutting machines has been remarkably improved, and the cutting speed tends to be increased in conjunction with the labor saving of the cutting process.
In cutting tools composed of N-base ultra-high pressure sintered materials,
When this is used for high-speed cutting, wear progresses quickly, and at present, the service life is reached in a relatively short time.

[0004]

Means for Solving the Problems In order to solve the above problems, the present inventors have paid attention to the above-mentioned conventional CBN-based sintered material, and have conducted research to further improve the wear resistance thereof. As a result, as a raw material powder, within the range of 1 to 10 μm
Powder having a predetermined average particle size, metal carbonitride
For powder, Al ₂ O ₃ powder, and Al (OH) ₃ powder
First, the CBN powder and the Al (OH) ₃ powder
After stirring and mixing in an NH ₄ OH solution,
Adjusting the Al ₂ O ₃ enclosing CBN powder wrapped in more Al ₂ O ₃
Then, these raw material powders are blended, and these blended powders are
Each is charged into a grinding mill lined with WC-base cemented carbide
And adding methyl alcohol to the powder mixture.
And after mixing, place the mill lid in an argon atmosphere.
And fired to evaporate the methyl alcohol,
Dry and then separately in an argon atmosphere
At the bottom of the prepared cylindrical container made of Ti,
Insert a WC-based cemented carbide disk and place it on top of this disk.
The mixed powder is charged, pressed with a push rod and filled.
Place a WC-based cemented carbide disk on the mixed powder, and then
After taking it out of the atmosphere of Lugon, put on the top lid made of Ti
Press and press to mix the powder mixture in the Ti cylindrical container.
Compress the thickness and subsequently dissolve the top lid in the cylindrical container
Touch and seal it, thus filling the above mixed powder
And sealed the cylindrical container into the ultra-high pressure and ultra-high temperature generator
And maximum applied pressure: 4-5 GPa, temperature range: 1300-
After holding at 1500 ° C, release pressure after cooling
Is performed, an Al ₂ O ₃ layer is interposed between the carbon nitride of the metal forming the binder phase in the CBN-based sintered material and the CBN particles, that is, the surface of the CBN particles is continuously or intermittently surrounded by Al ₂ O _3. When the layer is formed, the Al ₂ O ₃ surrounding layer has excellent adhesion to both the CBN particles and the binder phase. Therefore, even if high-speed cutting is performed using this as a cutting tool, Since the falling off of the steel is remarkably suppressed, the research results have shown that the steel exhibits more excellent wear resistance and shows excellent cutting performance over a long period of time.

The present invention has been made on the basis of the above research results, and has a raw material powder within a range of 1 to 10 μm.
Powder having a predetermined average particle size, metal carbonitride
For powder, Al ₂ O ₃ powder, and Al (OH) ₃ powder
First, the CBN powder and the Al (OH) ₃ powder
After stirring and mixing in an NH ₄ OH solution,
Adjusting the Al ₂ O ₃ enclosing CBN powder wrapped in more Al ₂ O ₃
Then, these raw material powders are blended, and these blended powders are
Each is charged into a grinding mill lined with WC-base cemented carbide
And adding methyl alcohol to the powder mixture.
And after mixing, place the mill lid in an argon atmosphere.
And fired to evaporate the methyl alcohol,
Dry and then separately in an argon atmosphere
At the bottom of the prepared cylindrical container made of Ti,
Insert a WC-based cemented carbide disk and place it on top of this disk.
The mixed powder is charged, pressed with a push rod and filled.
Place a WC-based cemented carbide disk on the mixed powder, and then
After taking it out of the atmosphere of Lugon, put on the top lid made of Ti
Press and press to mix the powder mixture in the Ti cylindrical container.
Compress the thickness and subsequently dissolve the top lid in the cylindrical container
Touch and seal it, thus filling the above mixed powder
And sealed the cylindrical container into the ultra-high pressure and ultra-high temperature generator
And maximum applied pressure: 4-5 GPa, temperature range: 1300-
After holding at 1500 ° C, release pressure after cooling
And performing, T as binder phase forming component
i, one or more of carbides, nitrides and carbonitrides of Zr and Hf: 20 to 40 vol%, aluminum oxide: 6 to 40 vol%, cubic boron nitride as a dispersed phase forming component: remaining, 1-20 vol% in the total composition of the above-mentioned aluminum oxide,
A continuous or intermittent envelope layer is formed on the surface of the cubic boron nitride particles, and the remaining aluminum oxide has a structure dispersed and present in the binder phase, and has substantially the same composition as the composition.
The present invention is characterized by a method for producing a cubic boron nitride-based ultrahigh-pressure sintered material having a composition and excellent wear resistance.

Next, the CBN-based ultra-high pressure sintered material of the present invention
The reason why the composition is limited as described above in the production method described above will be described. (a) Metal carbonitrides : These components have the effect of improving heat resistance and sinterability, but if their proportion is less than 20%, the desired effect cannot be obtained in the above-mentioned effects. When the ratio exceeds 40%,
Since the wear resistance is reduced, the ratio is set to 2
It was set to 0 to 40%. (b) Al ₂ O ₃ : Al ₂ O ₃ has an effect of improving strength, but if its proportion is less than 6%, the desired effect of improving strength cannot be obtained, while if its proportion exceeds 40%, Since the abrasion resistance is reduced, the ratio is set to 6 to 40%. (c) Al ₂ O ₃ surrounding layer : The Al ₂ O ₃ surrounding layer has excellent adhesion to both CBN particles as a disperse phase forming component and metal carbonitride as a binder phase forming component. Therefore, by forming the envelope layer of the CBN particles with Al ₂ O ₃ , the bonding strength between the CBN particles and the carbonitride of the metal is further improved, and as a result, the falling off of the CBN particles is significantly suppressed, and the wear resistance is improved. However, if the ratio is less than 1% of the total, the desired effect cannot be obtained in the above-mentioned operation, while if the ratio exceeds 20%, the thickness of the surrounding layer is not increased. Becomes too large and the abrasion resistance is reduced, so that the ratio is set to 1 to 20% in the whole.

[0007]

EXAMPLES Next, the method for producing a CBN-based ultrahigh-pressure sintered material of the present invention will be specifically described with reference to Examples. CBN powder having a predetermined average particle size in the range of 1 to 10 μm, carbonitride powder of various metals, and Al
₂ O ₃ powder and further Al (OH) ₃ powder are prepared, and the CBN powder and the Al (OH) ₃ powder are first stirred and mixed in an NH ₄ OH solution, and then dried at 130 ° C. Al ₂ O ₃ surrounding C wrapped with Al ₂ O ₃ in the proportions shown in FIG.
BN powder was prepared, these raw material powders were respectively blended into the blending composition shown in Table 1, and these blended powders were respectively charged into a grinding mill lined with a WC-based cemented carbide,
Further, 40% by volume of methyl alcohol was added to the blended powder and mixed for 24 hours. After mixing, the lid of the mill was opened in an argon atmosphere, and the mill was evaporated to a temperature of 130 ° C. to evaporate the methyl alcohol. And then dried, and then prepared in the same manner in an argon atmosphere by using a separately prepared inner diameter: 10
At the bottom of a cylindrical container made of Ti having a size of mφ × height: 15 mm, a disk made of a WC-based cemented carbide having a size of 9.8 mmφ × thickness: 2 mm prepared separately was first mounted on the bottom of a cylindrical cylindrical container made of Ti. Then, the mixed powder is charged into the disc so as to have a thickness of 7 mm, lightly pressed with a push rod and filled, and a 2 mm-thick WC-based cemented carbide disc is placed on the filled mixed powder. And then taken out of the argon atmosphere, further covered with a Ti top cover and pressed to compress the mixed powder in the Ti cylindrical container to a thickness of 5.5 mm. The upper lid is welded to the container, which is sealed, and the cylindrical container thus filled and sealed with the mixed powder is charged into a known ultra-high pressure and ultra-high temperature generator, and the maximum applied pressure is 4 to 5 GPa. ,
Temperature range: After holding at 1300 to 1500 ° C. for 30 minutes, the pressure is released after cooling, so that the WC has substantially the same composition as the compounded composition and the WC
The present invention in a state where diffusion bonded to the base cemented carbide of the upper and lower disc
The CBN group ultrahigh pressure sintered material 1-9 by manufactured respectively. In addition, as shown in Table 2, Al ₂
Under the same conditions except that the O ₃ envelope layer is formed, the conventional CB
N-based ultra-high pressure sintered materials 1 to 9 were produced.

[0008] Next, the silver solder in a square shape of WC-based cemented carbide tip with CBN based ultrahigh pressure sintered material 1-9 a conventional CBN based ultrahigh pressure sintered material 1-9 were separately prepared according to the aforementioned present invention Fixed, and finished the nose radius to 0.4 mm to make a cutting tool. Work material: carburized hardened steel (Rockwell hardness: 60), cutting speed: 200 m / min, feed: 0.08 m
A continuous high-speed cutting test was performed on high-hardness steel under the conditions of m / rev and a depth of cut of 0.1 mm, and the cutting time until the flank wear width of the cutting edge reached 0.2 mm was measured. (The results of these measurements are shown in Tables 1 and 2.)

[0009]

[Table 1]

[0010]

[Table 2]

[0011]

According to the present invention , based on the results shown in Tables 1 and 2 ,
The CBN-based ultra-high pressure sintered materials 1 to 9 according to the present invention are much better than the conventional CBN-based ultra-high pressure sintered materials 1 to 9 when they are used as cutting tools and high-speed cutting of high hardness steel is performed. It is clear that it shows wear resistance and exhibits excellent cutting performance over a long period of time.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C04B 35/583-35/5835

Claims (1)

(57) [Claims] Claims: 1. A raw material powder within a range of 1 to 10 μm.
Powder having a predetermined average particle size, metal carbonitride
For powder, Al ₂ O ₃ powder, and Al (OH) ₃ powder
First, the CBN powder and the Al (OH) ₃ powder
After stirring and mixing in an NH ₄ OH solution,
Adjusting the Al ₂ O ₃ enclosing CBN powder wrapped in more Al ₂ O ₃
Then, these raw material powders are blended, and these blended powders are
Each is charged into a grinding mill lined with WC-base cemented carbide
And adding methyl alcohol to the powder mixture.
And after mixing, place the mill lid in an argon atmosphere.
And fired to evaporate the methyl alcohol,
Dry and then separately in an argon atmosphere
At the bottom of the prepared cylindrical container made of Ti,
Insert a WC-based cemented carbide disk and place it on top of this disk.
The mixed powder is charged, pressed with a push rod and filled.
Place a WC-based cemented carbide disk on the mixed powder, and then
After taking it out of the atmosphere of Lugon, put on the top lid made of Ti
Press and press to mix the powder mixture in the Ti cylindrical container.
Compress the thickness and subsequently dissolve the top lid in the cylindrical container
Touch and seal it, thus filling the above mixed powder
And sealed the cylindrical container into the ultra-high pressure and ultra-high temperature generator
And maximum applied pressure: 4-5 GPa, temperature range: 1300-
After holding at 1500 ° C, release pressure after cooling
And performing, T as binder phase forming component
i, one or more of carbides, nitrides and carbonitrides of Zr and Hf: 20 to 40 vol%, aluminum oxide: 6 to 40 vol%, cubic boron nitride as a dispersed phase forming component: remaining, 1-20 vol% in the total composition of the above-mentioned aluminum oxide,
A continuous or intermittent envelope layer is formed on the surface of the cubic boron nitride particles, and the remaining aluminum oxide has a structure dispersed and present in the binder phase, and has substantially the same composition as the composition.
A method for producing a cubic boron nitride based ultra-high pressure sintered material having a composition and excellent wear resistance.