JPH0780708A - Fiber-reinforced aluminum oxide group ceramics-made cutting tool - Google Patents

Abstract

PURPOSE:To provide a fiber-reinforced aluminium oxide group ceramics-made cutting tool excellent in abrasion resistance and chipping resistance by containing SiO2-CaO-Al2O3 glass and the carbonate material fiber of Si and Ti. CONSTITUTION:The carbonate material fiber of Si and Ti has low reactivity with iron under high temperature during cutting, and an aluminum oxide group ceramics-made cutting tool, wherein this carbonate material fiber of Si and Ti is dispersed in a base to be fiber-reinforced, sharply increases abrasion resistance and chipping resistance. The breakage resistance can be improved by containing SiO2-CaO-Al2O3 glass of 3-20wt.% into aluminum in the base. The component composition of SiO2-CaO-Al2O3 glass is composed of CaO of 5-30wt.%, Al2O3 of 20-40wt.%, and the rest of SiO2 and inevitable impurity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting tool made of fiber reinforced aluminum oxide based ceramics having excellent wear resistance and fracture resistance.

[0002]

2. Description of the Related Art In recent years, aluminum oxide-based ceramics have come to be used for cutting tools, and in order to improve the fracture resistance of the cutting tools made of aluminum oxide-based ceramics, aluminum oxide-based ceramics are
A cutting tool made of fiber-reinforced aluminum oxide-based ceramics in which silicon carbide whiskers having a diameter of 1 μm or less and a length of 20 μm or less are dispersed is also known (JP-A-61-1).
74165). This fiber-reinforced aluminum oxide-based ceramics cutting tool is mainly used for rough cutting of cast iron or Ni-based alloy because of its excellent fracture resistance.

[0003]

However, in recent years, rough cutting of cast iron or the like has come to be performed under more severe conditions in order to improve productivity, and it is more common to perform cutting under more severe conditions than before. Cutting tools made of fiber-reinforced aluminum oxide-based ceramics using SiC whiskers still lack wear resistance and fracture resistance, shortening tool life and requiring frequent tool replacement, leading to reduced cutting work efficiency. There was a problem.

[0004]

Therefore, the present inventors have
As a result of conducting research to obtain a fiber-reinforced aluminum oxide-based ceramics cutting tool that is more excellent in wear resistance and fracture resistance than the conventional SiC whisker-based fiber-reinforced aluminum oxide-based ceramics cutting tool, (a)
Carbon oxide fibers of Si and Ti have lower reactivity with iron at high temperatures during cutting than conventional SiC whiskers.
Aluminum oxide-based ceramics cutting tools that are fiber-reinforced by dispersing carbon dioxide fibers of Ti and Ti in the substrate are more resistant than conventional aluminum oxide-based ceramics cutting tools that are fiber-reinforced by dispersing SiC whiskers in the substrate. Abrasion resistance and fracture resistance are greatly improved. (B) The base material is aluminum oxide with S as compared to aluminum oxide alone.
iO ₂ -CaO-Al ₂ O ₃ based glass or SiO ₂ -
The inclusion of 3 to 20% by weight of Li ₂ O-Al ₂ O ₃ -based glass improves the fracture resistance, and the SiO ₂ -CaO-Al
_The composition of the ₂ O ₃ glass is preferably 5 to 30% by weight of CaO, 20 to 40% by weight of Al ₂ O ₃ , and the balance: SiO ₂ and inevitable impurities, and further, the above SiO ₂ —Li ₂ The composition of the O—Al ₂ O ₃ glass is Li ₂ O: 1 to 20% by weight, Al ₂ O ₃ : 20 to 5%.
It is preferable that 0% by weight and the balance: SiO ₂ and unavoidable impurities are contained, but these glasses contain other oxides of alkali metals, oxides of alkaline earth metals, oxides of rare earth metals, oxides of Fe group metals, respectively. One or two or more of these: 15 wt% or less may be contained, and the research results were obtained.

The present invention has been made on the basis of the results of such research, and is SiO ₂ —CaO—Al ₂ O ₃ -based glass or SiO ₂ —Li ₂ O—Al ₂ O ₃ -based glass: 3 to 20 weight. %, Si and Ti carbonate fibers: 5
30 wt%, the balance is composed of a sintered body having an aluminum oxide, blending composition consisting of, the SiO ₂ -C
aO-Al ₂ O ₃ based glass, CaO: 5 to 30 wt%, Al ₂ O _3: 20 to 40 wt%, the balance has a component composition consisting of SiO ₂ and unavoidable impurities, also the S
The iO ₂ —Li ₂ O—Al ₂ O ₃ based glass is Li ₂ O:
1 to 20% by weight, Al ₂ O ₃ : 20 to 50% by weight, the balance: SiO ₂ and unavoidable impurities, and the above glass may further contain other alkali metal oxides, if necessary. Characterized by a fiber-reinforced aluminum oxide-based ceramic cutting tool containing one or more oxides of alkaline earth metal oxides, rare earth metal oxides and Fe group metal oxides: 15% by weight or less Is.

The fiber-reinforced aluminum oxide-based ceramics cutting tool of the present invention is a SiO 2 having the above-mentioned composition.
₂ -CaO-Al ₂ O ₃ based glass and SiO ₂ -Li
₂ O-Al ₂ O ₃ -based glass is produced, these glasses are crushed into glass powder, and the glass powder is mixed with carbon oxide fibers of Si and Ti and aluminum oxide powder, molded, and sintered. Manufactured.

The aluminum oxide-based ceramics cutting tool made of the sintered body manufactured as described above is further heat-treated to crystallize the glass of the sintered body, resulting in heat plastic deformation and cutting edge sharpening during cutting. The uneven wear due to is further improved.

With respect to the cutting tool made of the fiber-reinforced aluminum oxide-based ceramics of the present invention, the reason why the raw material composition and the glass composition are limited as described above will be explained.

(1) SiO ₂ —CaO—Al ₂ O ₃ type glass If this glass powder is blended in an amount of more than 20% by weight, the hardness becomes too low and the wear resistance decreases, which is not preferable. Even if it is blended in an amount of less than 3% by weight, it is not preferable because the carbon oxide fibers of Si and Ti and aluminum oxide cannot be sufficiently bonded and the fracture resistance is not improved. Therefore, the compounding amount of the SiO ₂ —CaO—Al ₂ O ₃ based glass is set to 3 to 20% by weight.

Further, the above SiO ₂ --CaO--Al ₂ O ₃
When the content of CaO exceeds 30% by weight, the softening point of the glass becomes too low, resulting in poor wear resistance and heat distortion resistance. On the other hand, when CaO is less than 5% by weight, sinterability is low. It is not preferable because the cutting resistance decreases and the fracture resistance of the cutting tool becomes insufficient. Further, when Al ₂ O ₃ exceeds 40% by weight, the sinterability is insufficient and the fracture resistance of the cutting tool is lowered, which is not preferable, while when Al ₂ O ₃ is less than 20% by weight, the hardness of the glass decreases. As a result, the wear resistance and heat distortion resistance of the cutting tool become insufficient, which is not preferable. Therefore, SiO ₂ -Ca used in the present invention
The content of CaO and Al ₂ O ₃ of O-Al ₂ O ₃ based glass, CaO: 5 to 30 wt%, Al ₂ O _3: 20~
It was set to 40% by weight.

(2) SiO ₂ --Li ₂ O--Al ₂ O ₃
System glass For this SiO ₂ —Li ₂ O—Al ₂ O ₃ system glass, the compounding amount was set to 3 to 20% by weight for the same reason as the above SiO ₂ —CaO—Al ₂ O ₃ system glass.

The above-mentioned SiO ₂ --Li ₂ O--Al ₂ O
_With respect to the compositional composition of the ₃ type glass, when the Li ₂ O content exceeds 20% by weight, the softening point of the glass becomes too low, resulting in poor wear resistance and heat distortion resistance, while Li ₂ O content is 1% by weight.
If it is less than the above range, the sinterability is lowered and the fracture resistance of the cutting tool is insufficient, which is not preferable. Further, when Al ₂ O ₃ exceeds 50% by weight, the sinterability is insufficient and the fracture resistance of the cutting tool is deteriorated, which is not preferable, while when Al ₂ O ₃ is less than 20% by weight, the hardness of the glass decreases. As a result, the wear resistance and heat distortion resistance of the cutting tool become insufficient, which is not preferable. Therefore, the SiO ₂ used in the present invention
-Li ₂ O-Al ₂ in O ₃ based glass Li ₂ O and Al
The content of ₂ O ₃ is Li ₂ O: 1 to 20 wt%, Al ₂
O ₃ : It was set to 20 to 50% by weight.

The glass such as the SiO ₂ —CaO—Al ₂ O ₃ type glass and the SiO ₂ —Li ₂ O—Al ₂ O ₃ type glass may contain oxides of other alkali metals or alkaline earth depending on the type of raw material. Oxides of group metals, oxides of rare earth metals and oxides of Fe group metals may be contained, but if the content exceeds 15% by weight, the hardness of the glass becomes too low and the wear resistance of the cutting tool is increased. The content of the oxide contained in the glass is set to 15% by weight or less in order to reduce the property.

(3) Carbon oxide fiber of Si and Ti The carbon oxide fiber of Si and Ti is blended to enhance the fiber resistance of the sintered body and improve the fracture resistance of the cutting tool made of this sintered body. However, if the content is more than 30% by weight, the wear resistance is lowered, which is not preferable, while if less than 5% by weight, the effect of improving the fracture resistance cannot be obtained.
The compounding amount of the carbon dioxide fibers of Ti and Ti was set to 5 to 30% by weight. The Si and Ti carbonate fibers blended in the present invention may be commercially available ones,
Its composition is Ti: 2.0 to 20% by weight, O: 10 to
It is preferable to have a composition of 30% by weight, C: 30 to 50% by weight, the balance: Si and inevitable impurities. In particular, when added to a cutting tool, a large amount of Si and C is likely to react with iron or an iron alloy, so that a larger content of Ti and O is preferable, but if the content of Ti and O is too large, the strength is increased. The lower limit of Ti is 20
The upper limit of O to 30% by weight was suppressed to 30% by weight. Furthermore, the above Si and Ti carbonate fibers do not need to have a uniform composition throughout, and may be fibers in which Ti and O are unevenly distributed in the outer peripheral portion, and the average thickness thereof is 1.0 to Thirty
It is preferable to use short fibers cut into a range of μm and average length of 0.05 to 2.0 mm. The reason is as follows.

If the average thickness of the above Si and Ti carbonate fibers is less than 1.0 μm, the fiber is too thin and lacks in toughness, and the fiber-reinforced aluminum oxide-based ceramic cutting tool using this fiber has sufficient fracture resistance. This is because it cannot be improved, and on the other hand, if the average thickness exceeds 30 μm, bending strength is lowered by the same function as coarse particles and the fracture resistance is also lowered, which is not preferable.

Furthermore, if the average length of the Si and Ti carbonate fibers is less than 0.05 mm, the toughness of the cutting tool made of fiber reinforced aluminum oxide-based ceramics decreases, while 2.0
This is because if the length is longer than mm, the toughness is lowered because the particles are not uniformly dispersed in aluminum oxide, and the fracture resistance of the fiber-reinforced aluminum oxide-based ceramics cutting tool is lowered, which is not preferable.

[0017]

【Example】

Example 1 SiO ₂ —CaO—Al ₂ O _{3 having the} component composition shown in Tables 1 to 3 by melting at 1600 ° C. and then rapidly cooling.
A system glass was prepared, and this glass was crushed to obtain an average particle size:
A 0.8 μm SiO ₂ —CaO—Al ₂ O ₃ based glass powder was prepared, and a composition consisting of Ti: 7% by weight, O: 14% by weight, C: 40% by weight, and the balance: Si and unavoidable impurities was prepared. Having, average thickness: 5 μm, average length: 0.
A 4 mm Si and Ti carbonate fiber was prepared.

The SiO ₂ —CaO—Al ₂ O ₃ glass powder and the Si and Ti carbonate fibers are mixed with Al ₂ O ₃ powder having an average particle diameter of 0.8 μm as shown in Tables 1 to 3. The powder mixture is blended so as to have a composition and mixed so as to be uniform, and the obtained powder mixture is press-molded at 1 kg / mm ² to prepare a powder compact, and the powder compact is heated at a temperature of 1350 ° C. for 1 hour. After sintering under the holding conditions, heat treatment was further performed under the conditions shown in Tables 4 to 5, and then gradual cooling was performed to perform crystallization treatment. SiO ₂ -CaO-Al by X-ray diffraction
The presence of a polycrystal of a ₂ O ₃ complex oxide was confirmed, and it was confirmed that it was crystallized. From this sintered body, cutting tools made of the fiber reinforced aluminum oxide-based ceramics of the present invention (hereinafter referred to as the cutting tool of the present invention) 1 to 15 of the ISO standard SNGN120408 shape, comparative fiber-reinforced aluminum oxide-based ceramics cutting tools (hereinafter referred to as comparative cutting) 1 to 9 were produced.

For comparison, the average thickness: 3 μm,
An SiC whisker having an average length of 50 μm was prepared, and 25% by weight of this SiC whisker was mixed with Al ₂ O ₃ powder, similarly wet mixed in a ball mill and dried, and then a conventional fiber of ISO standard SNGN120408 shape was prepared. Cutting tool made of reinforced aluminum oxide based ceramics (hereinafter,
Conventional cutting tool) was produced. For these cutting tools 1 to 15 of the present invention, comparative cutting tools 1 to 9 and conventional cutting tools, work material: SNCM440 (H _B 240) round steel bar, cutting speed: 330 m / min, feed: 0.24 mm / rev, Cutting: 1.2 mm, cutting time: 10 minutes, wet high speed continuous cutting test is performed, flank wear amount is measured, and work material: FC30 (H _B 200) square material, cutting speed: 250 m / Min, feed: 0.31 mm, depth of cut: 1.0 mm / rev, cutting time: 10 minutes, a wet interrupted heavy cutting test was performed to check for the occurrence of defects, and the results are shown in Tables 4-5. Indicated.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

[Table 4]

[0024]

[Table 5]

Example 2 Melting at 1600 ° C., followed by rapid cooling, SiO ₂ —Li ₂ O—Al ₂ O having the component compositions shown in Tables 6-8.
₃ type glass was prepared, this glass was crushed, and the average particle size was:
0.8 μm SiO ₂ —Li ₂ O—Al ₂ O ₃ based glass powder was prepared, and further, Ti: 12% by weight, O: 12% by weight, C: 35% by weight, and the balance: Si and inevitable impurities. The composition, average thickness: 7 μm, average length: 6
00 μm Si and Ti carbonate fibers were prepared. Tables 6 to 8 show the above SiO ₂ —Li ₂ O—Al ₂ O ₃ based glass powders, Si and Ti carbonate fibers and Al ₂ O ₃ powders prepared in Example 1 and having an average particle diameter of 0.8 μm. The powder mixture is blended so as to have the compounding composition shown in the following, uniformly mixed by a mixer, and the resulting mixed powder is press-molded at 1 kg / mm ² to prepare a green compact. After sintering for 5 hours, a heat treatment was performed under the conditions shown in Tables 9 to 10 and then a slow cooling to perform a crystallization treatment. SiO ₂ -CaO-Al by X-ray diffraction
The presence of a polycrystal of a ₂ O ₃ complex oxide was confirmed, and it was confirmed that it was crystallized. The cutting tools 16 to 29 of the present invention and the comparative cutting tools 10 to 18 having the ISO standard SNGN120408 shape were produced from this sintered body.
Then, using the cutting tools 16 to 29 of the present invention and the comparative cutting tools 10 to 18, a high-speed continuous cutting test and an interrupted heavy cutting test were performed under the same conditions as in Example 1, and the flank wear amount and the presence or absence of chipping were measured. , The measurement results thereof are shown in Table 9-
The results are shown in Table 10.

[0026]

[Table 6]

[0027]

[Table 7]

[0028]

[Table 8]

[0029]

[Table 9]

[0030]

[Table 10]

[0031]

From the results shown in Tables 1 to 10, it can be seen that the cutting tools 1 to 29 of the present invention have significantly improved wear resistance and fracture resistance as compared with the conventional cutting tools.
However, the comparative cutting tool 1 which is out of the condition of the present invention
It is understood that Nos. 18 to 18 are inferior in at least one of wear resistance and fracture resistance as compared with the cutting tools 1 to 29 of the present invention. Therefore, the fiber-reinforced aluminum oxide-based ceramics cutting tool of the present invention is superior in wear resistance and chipping resistance to the conventional fiber-reinforced aluminum oxide-based ceramics cutting tool, and thus is more severe than before. The tool life is not shortened even for cutting, the cutting work efficiency can be greatly improved, and it can greatly contribute to the development of industry.

Claims (4)

[Claims] 1. Sintering having a compounding composition consisting of SiO ₂ —CaO—Al ₂ O ₃ based glass: 3 to 20% by weight, Si and Ti carbonate fiber: 5 to 30% by weight, and the balance: aluminum oxide. It is composed of a body and has the above-mentioned SiO ₂ —CaO—Al ₂
The O ₃ -based glass has a component composition consisting of CaO: 5 to 30% by weight, Al ₂ O ₃ : 20 to 40% by weight, and the balance: SiO ₂ and unavoidable impurities. A cutting tool made of fiber-reinforced aluminum oxide-based ceramics with excellent performance. 2. Sintering having a compounding composition consisting of SiO ₂ —CaO—Al ₂ O ₃ based glass: 3 to 20% by weight, Si and Ti carbonate fiber: 5 to 30% by weight, and the balance: aluminum oxide. It is composed of a body and has the above-mentioned SiO ₂ —CaO—Al ₂
O ₃ type glass includes CaO: 5 to 30% by weight, Al ₂ O ₃ : 20 to 40% by weight, alkali metal oxides, alkaline earth metal oxides (excluding CaO), and rare earth metal oxidations. 1 or 2 or more of iron oxides and iron group metal oxides: 15% by weight or less, balance: SiO ₂ and unavoidable impurities, which are excellent in wear resistance and fracture resistance. Cutting tool made of fiber reinforced aluminum oxide based ceramics. 3. A compounding composition comprising SiO ₂ —Li ₂ O—Al ₂ O ₃ based glass: 3 to 20% by weight, Si and Ti carbonate fiber: 5 to 30% by weight, and the balance: aluminum oxide. It is composed of a sintered body and has the above-mentioned SiO ₂ —Li ₂ O—Al
_{The 2} O ₃ glass has a wear resistance characterized by having a composition of Li ₂ O: 1 to 20% by weight, Al ₂ O ₃ : 20 to 50% by weight, and the balance: SiO ₂ and unavoidable impurities. Cutting tool made of fiber reinforced aluminum oxide based ceramics with excellent fracture resistance. 4. A compounding composition comprising SiO ₂ —Li ₂ O—Al ₂ O ₃ based glass: 3 to 20% by weight, carbon oxide fibers of Si and Ti: 5 to 30% by weight, and the balance: aluminum oxide. It is composed of a sintered body and has the above-mentioned SiO ₂ —Li ₂ O—Al
₂ O ₃ glass includes Li ₂ O: 1 to 20% by weight, Al ₂ O ₃ : 20 to 50% by weight, oxides of alkali metals (excluding Li ₂ O), oxides of alkaline earth metals. , One or more of rare earth metal oxides and iron group metal oxides: 15% by weight
Hereinafter, a cutting tool made of fiber reinforced aluminum oxide-based ceramics having excellent wear resistance and chipping resistance, which has a composition of the balance: SiO ₂ and inevitable impurities.