JPS59232968A - Carbonitride ceramic for cutting tool and manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] This invention has high hardness and high toughness, and exhibits excellent cutting performance when used as a cutting tool for high-speed cutting of steel, cast iron, etc., which particularly require these characteristics. This invention relates to carbonitride-based ceramics and methods for producing them.

In general, in the field of cutting tools, there has been a trend in recent years to require cutting at high cutting speeds to improve productivity.
For example, hard sintered materials such as tungsten carbide-based cemented carbide and titanium carbide-based cermet have excellent toughness, but they do not have sufficient wear resistance, so they cannot be used under harsh conditions such as high-speed cutting. , which does not exhibit a satisfactory cutting life.

Therefore, attempts have been made to use ceramic sintered materials made entirely of aluminum oxide, which have high hardness, that is, sufficient wear resistance, in the above fields, but these oxide ceramics have poor toughness. Due to its limited use, ceramic sintered materials are attracting attention. However, in the case of this material, since silicon nitride is a compound with strong covalent bonding, sintering is difficult, and for this reason, a hot pressing method is often used when manufacturing it. However, when using the hot pressing method, although a dense sintered material can be obtained, it is impossible to produce a sintered material with a complicated 5-shaped shape, and the productivity is low.

Furthermore, silicon nitride also has high sintering properties and excellent thermal shock resistance and oxidation resistance. Part of the Si in the β-8i3N4 lattice is replaced with M and part of the N is replaced with zero. Good compound, that is, compositional formula: Si fi-2Mzo□N 8-Z (however, O< z
≦4゜3).

Attempts have also been made to use a sialon-based ceramic sintered material containing β-sialon as a main component as a cutting tool; Due to the high reactivity between the component Si and the Fe in the work material, flank wear and rake face wear on the cutting edge develop significantly, resulting in insufficient wear resistance (cutting life). is the current situation.

Therefore, the inventors of the present invention have found that, from the viewpoint of "duplex", it is possible to achieve both high strength and high toughness under normal sintering conditions without using a hot press method, etc., and that these properties are particularly required. As a result of conducting research to produce a material that exhibits excellent cutting performance when used as a cutting tool for high-speed cutting of steel, cast iron, etc., we found that ■ A composite carbonitride solid solution of Ti and W (hereinafter referred to as ( (hereinafter referred to as (Ml, Ti, W) C!N, therefore Ml represents one or more of Zr, Hf, V, Nb, and Ta) powder; ■ Ti and one or two of Or and MO; and a composite carbonitride solid solution of W (hereinafter referred to as (Ti 1 '
Mz +W') ON, Mz therefore represents one or two of Or and Mo) powder.

■ Composite carbonitride solid solution C of Ml, Ti, +M2, and W (indicated by Ml, Ti, Mz, W) ON) powder, any one of the above ■ to ■, Mg and Oa One or two of the powders of oxides of
oxide (hereinafter referred to as A++203°Y2O3, and Zr
One or more of the powders (indicated by O2): 1 to
Section 10: When a green compact formed by shiveless molding of a mixed powder comprising MgO
Most of the CaO powder is decomposed, and the resulting decomposition product 02 reacts with the carbon in the composite carbonitride solid solution powder, so that at the same time the carbon in the composite carbonitride solid solution decreases, the active As W precipitates (/i:nashi,
This precipitated W significantly accelerates sintering, and as mentioned above, most of it decomposes and reacts during sintering, but the remaining MgO and CaO
Since this suppresses the grain growth of the composite carbonitride solid solution as well as M2O3, Y2O3, and ZrO2, the obtained ceramics are dense and have high strength.

Furthermore, in the resulting ceramics.

The composite carbonitride solid solution is ■ A phase rich in Ti and N and a phase rich in W and C.

■ A phase rich in M, Ti, and N, and a phase rich in W and C.

■ A phase rich in T1 and N, and a phase rich in Mz, W, and C.

■ Ml, Ti, N-rich phase, %M2, and W.

C-rich phase.

Because it has one of the two-phase structures listed above, it must have high hardness and toughness, that is, excellent wear resistance and high transverse rupture strength, and be finely and uniformly dispersed. It was discovered that Ag2O3, Y2O3, and ZrO2, which have been added to the alloy, provide even better oxidation resistance and wear resistance.

This invention was made based on the above findings, and includes: (1) One or two of MgO and OaO = 0.01 to 1.

Contains one or more of M2O3+ Y2O3 and ZrO2: 1 to 10, and has a composition in which the remainder is (Ti, W)ON and unavoidable impurities, and the (Ti, W)ON is ,9
- A carbonitride-based ceramic for cutting tools having a two-phase structure of a phase rich in T1 and N and a phase rich in W and C.

(2) Contains one or two of MgO and CaO = 0.01 to 1 ratio, one or more of M2O3, Y2O3, and ZrO2: 1 to 10 ratio, and the remainder is ( It has a composition consisting of Ml, Ti, W) ON and inevitable impurities, and the above (Mi, Ti,
W)・CN is a carbonitride-based ceramic for cutting tools having a two-phase structure including a phase rich in Ml, Ti, and N, and a phase rich in W and C.

(3) Contains 1 to 10% of one or two of MgO and OaO, one or more of M2O31Y2O3+ and ZrO2, and the remainder is (T1.Mz, w) has a composition consisting of cN and unavoidable impurities, and has the above (Tl + Mz +
W)・ON is a Ti- and N-rich phase, hM2, and W,
Carbonitride ceramics for cutting tools with a two-phase structure consisting of a C-rich phase.

10- (4) Contains one or two of MgO and CaO: 0.01 to 10%; one or more of AjhO3, Y2O3, and ZrO2: 1 to 10%; has a composition consisting of (Ml, Ti, Ml, W) CN and inevitable impurities, and the (Ml
tTi+M2. W)C! N is M],! : , T
i, NvC rich phase (!: % Ml, W, OK
Carbonitride ceramics for cutting tools with a two-phase rich phase structure.

(5) ■ (Ti, W) ON powder, ■ (Ml, Ti, W) ON powder, ■ (Ti,
Ml, W) ON powder, ■(M,, Ti, Ml
, W) ON powder, one or two of MgO powder and CaO powder: 0.5 to 10 parts.

A powder compact formed by shibbling a mixed powder containing one or more of M2O3 powder, Y2O3 powder, and ZrO2 powder in ratios of 1 to 10 is heated to 1700 to 2100 in a non-oxidizing atmosphere. A method for manufacturing carbonitride ceramics for cutting tools whose main process is sintering at a temperature within the range of °C.

The carbonitride-based ceramics for cutting tools and the manufacturing method thereof shown in (1) to (5) above have the characteristics.

Next, in the ceramics of the present invention and the method for producing the same, the reasons why the amounts and contents of MgO and CaO and the sintering temperature are all limited to the above-mentioned values will be explained.

(a) Amount and content of MgO and CaO Most of these components decompose during sintering as described above, react with the composite carbonitride solid solution to promote sinterability, and a small amount of these components decompose during sintering. A large amount remains in the ceramic to form a composite carbonitride solid solution phase as well as 1'JJ20s + Y2O3
+ suppresses the grain growth of the oxide phase consisting of ZrO2,
This has the effect of densifying and strengthening the ceramic, but if the amount is less than 0.5%, the desired effect of improving sinterability cannot be obtained.The amount remaining in the ceramic is 0.01%. If the amount is less than 10%, the desired grain growth suppressing effect cannot be obtained. On the other hand, if the amount exceeds 10%, the amount remaining in the ceramic will exceed 1%, and a large amount of Since cavities occur and the deterioration of toughness and fracture resistance becomes significant, the blending amount was determined to be 0.5 to 1 O, and the content was determined to be 0.01 to 1.

(b) Afli203, Y2O3, and zr
02 Blend amount and content These ingredients have the effect of further improving the oxidation resistance and abrasion resistance of ceramics by dispersing them finely and uniformly, but if their blending amount, that is, the content is less than 1 part, If the desired improvement effect is not seen in the above-mentioned action, and on the other hand, if the blending amount, that is, the content exceeds the lO ratio, the toughness and fracture resistance of the ceramic will decrease. were defined as sections 1 to 10.

(C) Sintering temperature If the temperature is less than 1700°C, MgO and OaO will not be decomposed sufficiently, and therefore no improvement in sinterability can be expected. On the other hand, when the temperature exceeds 2100℃, M2
O3, Y2O3, and ZrO2 are also MgO and OaO
Since it decomposes in the same way as The temperature was set at 1700-2100°C.

Note that the composite carbonitride solid solution of this invention, that is, (Ml
, Ti, W) ON, (Ti, Ml, W) ON, and (M1+'I'i, Ml, W) c N, Ml is (Ti.

w) It is desirable that Ti in aN be contained in a substituted form within the range of 10 to 40 atoms; in this case, M1
If Ml is Zr and T(f, the wear resistance of the ceramic will be further improved, and if Ml is V, Nb, and Ta, the toughness and fracture resistance will be further improved.
Furthermore, Ml is the same <(Ti, W)l:! It is desirable to include a portion of W in N in the form of substitution with Or and MO within a range of 10 to 30 atoms, thereby further improving sinterability.

Next, the ceramics of the present invention and the method for producing the same will be specifically explained using examples.

Examples of raw material powders include various composite carbonitride solid solution powders each having the composition formula shown in Table 1 (the numbers in parentheses indicate the atomic ratio) and each having an average particle size of 1 μm. :0.5μm M2O3 powder.

Same Q, 5 μm Y2O3 powder, same 0.5 μm Zr 0
2nd Song Dynasty.

0.4pm of MgO powder and 0.511m of O
AO powder was prepared, and these raw material powders were blended into the composition shown in Table 1, wet pulverized and mixed in a ball mill for 72 hours, dried, and then press-molded into a green compact at a pressure of 15 Kp/-. Then, this green compact is sintered under the conditions also shown in Table 1 to produce ceramics 1 to 33 of the present invention having the component compositions also shown in Table 1.
and Comparative Ceramics 1 to 6 were manufactured, respectively.

In addition, comparative ceramics 1 to G all have a compounding composition (
The final component composition) and the sintering temperature (those marked with * in Table 1) are manufactured under conditions that are outside the scope of the present invention.

Next, the resulting ceramics of the present invention 1 to 33
For Comparative Ceramics 1 to 6, Vickers hardness was measured for the purpose of evaluating abrasion resistance, transverse rupture strength was measured for the purpose of evaluating toughness, and the entire state of bore generation was observed in accordance with ASTM standards.

These results are shown in Table 2.

From the results shown in Table 2, it can be seen that ceramics 1 to 3 of the present invention
Comparative ceramics 1 to 6 have high hardness, high toughness, and a dense structure.
As seen in , if either the blending composition (component composition) or the sintering temperature falls outside the scope of this invention,
It is clear that the harder the hardness and toughness are, the more likely it is that bores will occur. In Comparative Ceramic 3, the composite carbonitride solid solution had a two-phase structure, similar to Invention Ceramics 1 to 33.
In Comparative Ceramics 1, 2, 4, 5°, and 6, the composite carbonitride solid solution had a single-phase structure.

In addition, for the above-mentioned ceramics 1 to 33 of the present invention and comparative ceramics 1 to 6vC, chip shape: 5NP432 (honing: 0.2 x 2
5°), Work material: SNC! M-13 (hardness: HB2
40) round bar, cutting speed: 400m1m1n, feed rate: 0.2mm/rev, % depth of cut -1.5mm, cutting time: 10m1n, steel continuous high-speed cutting test under the following conditions, and chip shape:
5NP432 (honing: 0.1x25°), work material: F c 25 (hardness: HB150) square material, cutting speed: 500m7'mm, feed: 0. 2 5 in/rev
Intermittent high-speed cutting tests on cast iron were conducted under the following conditions: , depth of cut: 3, cutting time: 10 mm, and in the former cutting test, the entire flank wear width of the cutting edge was measured for the purpose of evaluating wear resistance, and in the latter In the cutting test, 10 cutting edges were tested for the purpose of evaluating toughness and fracture resistance.
The number of chipped cutting edges (number of chipped cutting edges/number of tested cutting edges) was checked. These results are shown in Table 2. Table 2 also shows commercially available M2O3-301Tj, C ceramics (conventionally referred to as ceramics 1) and Si3N
The cutting test results of 4-10%M2O3-5%AtN ceramics (conventionally referred to as ceramics 2) under the same conditions are also shown.

From the results shown in Table 2, it can be seen that ceramics 1 to 3 of the present invention
Since No. 3 has high hardness and high toughness, it is clear that it exhibits extremely superior wear resistance and chipping resistance compared to comparative ceramics Nos. 1 to 6, which are inferior in hardness and toughness, and commercially available ceramics, which are especially inferior in toughness. be.

As described above, according to the method of the present invention, it is possible to produce dense carbonitride ceramics having high hardness and high toughness without using a method such as full hot pressing. When carbonitride-based ceramics are used as cutting tools for high-speed cutting of steel, cast iron, etc., industrially useful effects such as excellent cutting performance over a long period of time can be obtained.

Applicant: Mitsubishi Metals Corporation Agent Tomi 1) Kazuo and 1 other person 25-

Claims (5)

[Claims] (1) One or two oxides of Mg and Ca: 0.01 to 1 weight tlI One or more oxides of Ag, Y, and Zr: 1 to 10 weight tlI contains Ti, and the remainder is Ti and W.
has a composition consisting of a composite carbonitride solid solution and inevitable impurities, and the composite carbonitride solid solution has a composition consisting of T1 and N
Carbonitride-based ceramics for cutting tools, characterized by having a two-phase structure including a phase rich in W and C and a phase rich in W and C. (2) One or two of the oxides of Mg and Ca: 0.01-1 weight ratio, one or more of the oxides of u, y, and Zr: 1 to 10 weight and the remainder consists of one or more of Zr, Hf, V, Nb, and Ta, Ti, a composite carbonitride solid solution of W, and unavoidable impurities; The composite carbonitride solid solution contains Zr, Hf, V
, Nb. and one or more of Ta and T1. A carbonitride-based ceramic for cutting tools, characterized by having a two-phase structure consisting of a phase rich in N and a phase rich in W and C. (3) One or two of Mg and Ca oxides: 0.01 to 1 weight ratio. One or more of Ag, Y, and Zr oxides: 1 to 10 weight coefficients, the rest being T1, and one or more of Or and MO.
The composite carbonitride solid solution has a composition consisting of a species, a composite carbonitride solid solution of W, and unavoidable impurities, and the composite carbonitride solid solution
A carbonitride-based ceramic for a cutting tool, characterized by having a two-phase structure including a phase rich in Ti and N, a phase rich in one or two of Cr and MO, and a phase rich in W and C. (4) One or two of Mg and Oa oxides: 0.01 to 1 weight ratio, A6. Contains 1 to 10% by weight of one or more oxides of Y and Zr, and the remainder is one or more of Zr, Hf, V, Nb, and Ta. , T1 and Or and M
The composite carbonitride solid solution contains 1m or 2 of O, a composite carbonitride solid solution of W, and inevitable impurities, and the composite carbonitride solid solution contains Zr, Hf, V, Nb.
, and one or more of Ta, and T1;
A carbonitride-based ceramic for a cutting tool, characterized by having a two-phase structure including a N-rich phase, one or two of Or and Mo, W, and a C-rich phase. (5)■ Composite carbonitride solid solution powder of Ti and W. ■ Composite carbonitride solid solution powder of one or more of Zr, Hf, V, Nb, and Ta, Ti, and W, ■ T1, and one or two of Or and Mo. , W composite carbonitride solid solution powder, ■ one or more of Zr, Hf, V, Nb, and Ta, Ti, Cr and MO
one or two of the above and a composite carbonitride solid solution powder of W; one or two of the oxide powders of Mg and Ca; 2nd class 20.5-10 weight class, A6. One or more of Y and Zr oxide powders: 1 to 10 weight ratio. A compacted powder body formed by Shibres molding of the mixed powder made of all the ingredients,
A method for producing carbonitride-based ceramics for cutting tools, characterized by sintering at a temperature within the range of 1700 to 2100°C in a non-oxidizing atmosphere.