JPS59195582A - Carbonitride ceramics 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 demand 9-cut processing 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 and cannot be used under harsh conditions such as high-speed cutting. does not show a satisfactory cutting life.

Therefore, attempts have been made to use ceramic sintered materials mainly made of aluminum oxide, which have high hardness, that is, sufficient wear resistance, in the above fields, but these oxide ceramics, on the other hand, have poor toughness. Because it is a thing, its uses are limited.

It is something that will be lost.

Furthermore, recently, silicon nitride-based ceramic sintered materials have attracted attention as materials for cutting tools. 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 shape, and productivity is low.

Furthermore, it is a compound in which part of 81 in the β-Si3N4 lattice is replaced with M and part of N with O, which has higher sinterability than silicon nitride and also has excellent thermal shock resistance and oxidation resistance. , that is, the composition formula: 5i6-z/V! zozNB-z (however, O<Z≦4
．． 3) Attempts have been made to use a sialon-based ceramic sintered material containing β-sialon as the main component as a cutting tool; However, due to the high reactivity between the constituent Sl and Fe in the workpiece material, flank wear and rake wear on the cutting edge develop significantly, making it difficult to achieve satisfactory wear resistance (cutting life). The current situation is that it is not shown.

Therefore, from the above-mentioned viewpoint, the present inventors have developed a steel that has both high strength and high toughness under normal sintering conditions without using the hot press method etc., and that particularly requires these characteristics. 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 cast iron, etc., we found that ■ A composite carbonitride solid solution of T1 and W (hereinafter referred to as (Tl)) was developed.

W) ON) powder, ■ Composite carbonitride solid solution of one or more of Zr, Hf, V, Nb, and Ta, T1, and W (hereinafter referred to as (Ml, Ti, W) (denoted by ON, therefore Ml represents one or more of Zr, Hf, V, Nb, and Ta) powder, ■ T1, one or two of Cr and MO, and W. Composite carbonitride solid solution (hereinafter referred to as (Tl, M2
+V/ ) ON, therefore Mg is Cr and MO.

(1 type 1 and 2 types) powder, ■ Composite carbonitride solid solution of M, T1, Mg, and W (hereinafter referred to as (Ml, Ti, Mg, W) ON) powder, and above ■ Mg in any one of ~■
A non-oxidizing powder compact is prepared by molding a mixed powder of 0.5 to 10% by weight of one or two of powders of oxides of Ca and Ca (hereinafter referred to as MgO and CaO). When sintered in an atmosphere at a temperature in the range of 1800 to 2500°C, most of the oxide powder is decomposed during sintering, and the resulting decomposition product 02 and the carbon in the composite carbonitride solid solution powder are reacts, the carbon in the composite carbonitride solid solution decreases, and at the same time, active W begins to precipitate, and this precipitated W significantly accelerates sintering, and as described above. Most of the oxide decomposes and reacts during sintering, but the remaining oxides of 0, 01 to 1 weight percentage (hereinafter referred to as weight percent) suppress grain growth of the composite carbonitride solid solution. As a result, the resulting ceramic is dense and has high strength9.Furthermore, in the resulting ceramic, the composite carbonitride solid solution consists of a phase rich in T1 and N, and a phase rich in W and C.

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

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

■ Ml, T1, N-rich phase, Mg, W, C
A phase rich in

Since it has one of the two-phase structures described in ~■ above, we have obtained the knowledge that it has high hardness and high toughness, that is, excellent wear resistance and high transverse rupture strength. be.

This invention was made based on the above findings, and includes: (1) one or two of MgO and CaO;

Contains 0.01 to 1 kesa, and the remaining p is (Ti, W)C! A carbonitride-based ceramic for cutting tools having a composition consisting of N and inevitable impurities, and in which the (Ti, W)ON has 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%, the remainder having a composition consisting of (Ml, Ti, W)ON and unavoidable impurities, and the above (Ml, Ti,
W) A carbonitride-based ceramic for cutting tools in which CN has a two-phase structure including a phase rich in Ml, T1, and N, and a phase rich in W and C.

(3) Contains 2001 to 1% of one or two of MgO and CaO, with the remainder consisting of (Ti, 'M2.W)CN and inevitable impurities;
, W) ON is a Ti- and N-rich phase, Mg, W, C
Carbonitride-based ceramics for cutting tools that have a two-phase structure with a phase rich in .

(4) Contains one or two of MgO and CaO: 0.01 to 1%, with the remainder consisting of (Ml, Ti, Mg, W)ON and unavoidable impurities;
,'l”i.

Mg, W) ON is a carbonitride-based specific ramix for cutting tools having a two-phase structure: a phase rich in Ml, Ti, and I, and a phase rich in Mg, W, and C.

(5) ■ (Ti, W) CN powder, ■ (M, Ti, W) CN powder, ■ (T
i, Mg, W) ON powder, ■ (Ml, Ti
, Mg, W) CN powder, press molding from a mixed powder obtained by blending 0.5 to 10% of one or two of MgO powder and CaO powder to any of the powders from ■ to ■ above. The green compact was heated in a non-oxidizing atmosphere for 1
A method for producing carbonitride ceramics for cutting tools, the main process of which is sintering at a temperature within the range of 800 to 2,500°C.

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

Next, the reason why the blending amount and content of MgO and OaO and the sintering temperature are limited as described above in the ceramics and the manufacturing method thereof of the present invention will be explained.

(a) Blending amount and content of MgO and CaO Most of these components are decomposed during sintering as described above, react with the composite carbonitride solid solution, and sinter.

It promotes coagulation, and a small amount of it remains in the ceramics and suppresses the grain growth of the composite carbonitride solid solution phase, thereby densifying and strengthening the ceramics. If the amount is less than 5%, not only will the desired sinterability improvement effect not be obtained, but the amount remaining in the ceramic will be less than 0.01%, making it impossible to obtain the desired grain growth suppressing effect. If the content exceeds 10%, the residual amount in the ceramic will exceed 1%, and a large number of cavities will occur in the ceramic, resulting in a significant deterioration of toughness and fracture resistance. Addition amount to 0
．． The content was determined to be 5 to 10% and 0.01 to 1%.

(1)) Sintering temperature If the temperature is less than 1800°C, the decomposition of %gO and OaO will not be sufficient, and therefore no improvement in sinterability can be expected. As the temperature increases to 250°C, cavities are likely to occur, and as a result, the toughness and fracture resistance of the ceramic decrease.
If the temperature exceeds 0°C, grain growth of the composite carbonitride solid solution will occur and the toughness and fracture resistance of the ceramic will decrease, so the temperature was set at 11,800 to 2,500°C.

Note that the composite carbonitride solid solution of this invention, that is, (M,
, Ti, w) cN, (T1.M2.W)
ON, and (Ml, Ti, M2.W) ON
Regarding (T1゜W), it is desirable that Ml be contained in the form of substituting a part of T1 in CN within the range of 10 to 40 atoms, and in this case, if M is Zr and Hf, the durability of the ceramic is If Ml is V, Nb, and Ta, the toughness and fracture resistance will be further improved, and if M2 is the same ((Ti
, w) aN may contain part of W in a substituted form within the range of 10 to 30 atoms.

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 (numbers in parentheses indicate atomic ratio) and each having an average particle size of 1 μm; average particle size: 0.4 μm MgO powder and 0.5 μm Oa
O powder was prepared, 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 pressed into a green compact at a pressure of 15 Kg/mA. Ceramics 1 to 26 of the present invention and comparative ceramics 1 to 5 were produced by molding and then sintering the green compacts under the same conditions shown in Table 1.

In addition, Comparative Ceramics 1 to 26 all have conditions in which either the compounding composition (final component composition) or the sintering temperature (those marked with * in Table 1) are outside the scope of this invention. It was manufactured by.

Next, the resulting ceramics of the present invention 1 to 26
And for comparative ceramics 1 to 5, MgO and Ca
In addition to measuring the O content, we also measured Vickers hardness and toughness for the purpose of fully evaluating wear resistance.

For the purpose of evaluation, the total transverse rupture strength was measured, and A S T l
The conditions of bore generation in accordance with the VL standard were observed. These results are also shown in Table 1.

From the results shown in Table 1, it can be seen that ceramics 1 to 2 of the present invention
Comparative ceramics 1 to 5 all have high hardness and high toughness as well as a dense structure.
As seen in the above, if either the blending composition (component composition) or the sintering temperature falls outside the scope of this invention, the hardness and toughness will be poor, and moreover, the occurrence of bores will occur frequently. is clear. Note that Comparative Ceramic 2 had a composite carbonitride solid solution having a two-phase structure like Ceramics 1 to 26 of the present invention, but Comparative Ceramic 1, 3, 4. In both cases, the composite carbonitride solid solution had a one-phase structure.

For the above-mentioned ceramics 1 to 26 of the present invention and comparative ceramics 1 to 5, chip shape: 5NP432 (honed 0.2X25
), rigid material SNCM-8 (hardness: HB220
) round bar, cutting speed, 50? 7Z/mm.

Feed: 0.2 mm/rev, Depth of cut: 1.5
wn.

Continuous high-speed steel cutting test under the conditions of cutting time, 10 mm, and chip shape: 5
NP432 (honing: 0.1X25°), rigid material
PC 25' (hardness: HB140) square material, cutting speed: 500 m/mUI.

A cast iron high-speed milling test was conducted under the following conditions: feed rate: 0.2rnm/tooth, depth of cut: 2mm, cutting time: 10m1i.In the former cutting test, flank wear of the cutting edge was measured for the purpose of evaluating wear resistance. The width was measured, and in the latter cutting test, 10 cutting edges were tested for the purpose of evaluating toughness and fracture resistance, and the number of fractured cutting edges (number of chipped cutting edges/number of tested cutting edges) was checked. . These results are shown in Table 1. Also, the first
The table includes commercially available AlI303-TiC for comparison purposes.
From the results shown in Ceramics and Table 1, Ceramics 1 to 26 of the present invention have high hardness and toughness, so they are superior to Comparative Ceramics 1 to 5, which are inferior in hardness and toughness, and especially compared to commercially available ceramics, which are inferior in toughness. It is clear that the material exhibits extremely excellent wear resistance and chipping resistance.

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

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

Claims (5)

[Claims] (1) Contains 1 to 1% by weight of one or two of the oxides of Mg and Ca: O, O, and the remainder consists of Ti, a composite carbonitride solid solution of W, and unavoidable impurities. A carbonitride-based ceramic for a cutting tool, wherein the composite carbonitride solid solution has a two-phase structure including a phase rich in T1 and N and a phase rich in W and C. (2) Contains 0.01 to 1% by weight of one or two of the oxides of Mg and Ca, and the remainder is one or two of the oxides of Zr, Hf, V, Nb, and Ta. It has a composition consisting of a composite carbonitride solid solution of species 1, T1, and W and unavoidable impurities,
The composite carbonitride solid solution contains Zr, Hf, V,
N'b. and one or more of Ta, Ti, 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. (3) Contains 0.01 to 1% by weight of one or two of the oxides of Mg and Oa, and the remaining 9 contains T1, one or two of Or and MO, and W The composite carbonitride solid solution has a composition consisting of T
A carbonitride-based ceramic for a cutting tool, characterized by having a two-phase structure consisting of a phase rich in 1 and N, a phase rich in one or two of Or and MO, W, and C. (4) Contains one or two of Mg and Ca oxides: 0.01 to 1% by weight, and the remainder is Zr, 'Hf, V, Nb, and T.
a, one or more of Ti, one or two of Cr and MO, and a composite carbonitride solid solution of W and unavoidable impurities, and the composite carbonitride The solid solution is Zr, Hf, V, N
b, and one or more of Ta, T1, a N-rich phase, one or two of Or and IAO, W, and a C-rich phase. Carbonitride-based ceramics for cutting tools that are characterized by: (5) ■ Composite carbonitride solid solution powder of T1 and W, ■ Z
one of r', Hf, V, Nb, and Ta
A composite carbonitride solid solution powder of a species or two or more species, T1, and W, ■ A composite carbonitride solid solution powder of T1, one or more of Or and MO, and W, ■ Zr, Hf , a composite carbonitride solid solution powder of one or more of V, Nb, and Ta, T1, one or two of Cr and Mo, and W;
The composite carbonitride solid solution powder of any of the above ■ to ■ is combined with one or two of the oxide powders of Mg and Oa.
A green compact press-molded from a mixed powder containing 0.5 to 10% of seeds by weight is heated to 1800 to 25% by weight in a non-oxidizing atmosphere.
A method for producing carbonitride ceramics for cutting tools, characterized by sintering at a temperature within the range of 00°C.