JPS599613B2 - Tough cermet containing oxygen - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tough oxygen-containing cermet with particularly excellent cutting properties.

Generally, during high-speed cutting, high stress is applied to the cutting edge and high frictional heat is generated, so the cutting edge is not exposed to high temperatures. was occurring.

Conventionally, high-speed cutting tool materials used under such harsh conditions have used titanium carbide (Titanium carbide) as a dispersed phase forming component.
(hereinafter referred to as TiC), titanium nitride (hereinafter referred to as TiN)
, and titanium carbonitride (hereinafter referred to as TiCN) (hereinafter referred to as TiCN), cermets containing dispersed one or more types (these are collectively referred to as titanium carbon/nitride) are known.

Among these carbon/titanium nitride dispersed cermets, nitrogen-containing cermets generate frictional heat because nitrogen content lowers their affinity with the rigid material compared to TiC dispersed cermets that do not contain nitrogen. The amount is relatively low, thus preventing softening of the cutting edge and reducing the phenomenon of chipping.

However, in any of these cermets, the wettability of the dispersed phase with the metal binding phase and grain growth are not as good as those of tungsten carbide (hereinafter referred to as WC)-based cemented carbide, and therefore there are limitations in terms of usage. This is the reality.

From the above-mentioned viewpoints, the present inventors have achieved excellent toughness by improving the bendability of the dispersed phase with the metal binder phase and suppressing grain growth, and as a result, achieved excellent cutting properties. As a result of research to obtain a cermet with a 70, one of the metals of Groups 4a+5a and 6a of the periodic table, excluding Ti
When using a multiple solid solution carbonitride powder consisting of a species or one substituted with two or more species, the multiple solid carbonitride powder has extremely little grain growth during sintering, and has extremely high wettability with the binder phase. The resulting cermet has excellent high-temperature strength, and especially when partially substituted with W or Mo, has even better plastic deformation resistance and toughness.

Titanium carbonate (hereinafter referred to as Ti) is used as the second dispersed phase forming component.
(hereinafter referred to as TiNO), titanium nitride oxide (hereinafter referred to as TiNO),
and titanium carbonitride (hereinafter referred to as T i C NO)
When one or more of these (hereinafter collectively referred to as carbon/titanium nitride oxide) is added to the above-mentioned multiple solid carbonitride dispersed cermet, it becomes the main dispersed phase during sintering. The plurality of carbonitride particles become spherical and the grain growth of these particles is significantly suppressed, and as a result, the plurality of carbonitride particles become extremely fine and uniform. The toughness of cermet is improved,
When such a cermet is used as a cutting tool material, the coefficient of friction between the cutting edge and the workpiece during cutting is reduced, which reduces the generation of frictional heat and improves plastic deformation resistance. thing.

(c) When aluminum nitride (hereinafter referred to as A7N) is added as a third dispersed phase forming component to the above-mentioned solid nitride dispersed cermet, the wettability of the dispersed phase with the metal binder phase is further improved. At the same time, a part of At in AtN solidifies in the binder phase and solidifies the binder phase, and especially when Ni is contained in the binder phase, fine biparticles, that is, {Ni3 (A/,)Ti) particles are precipitated into the binder phase and the high temperature strength of the cermet is significantly improved.

(d) When one or more Cr group metals are contained in a binder phase consisting of one or more iron group metals, the wettability of the dispersed phase with the binder phase is further improved. At the same time, the high temperature strength of cermet will further improve.

The findings shown in sections (a) to (d) above have been obtained.

Therefore, this invention has been made based on the above findings, and uses a cermet having a C/N>1 as a dispersed phase forming component by weight, and a part of Ti in titanium carbonitride is 10 to 10%. Plural carbonitrides consisting of those substituted with one or more metals of group 4a+5a+ and 6a of the periodic table excluding Ti in the range of 70 to 250~
Section 95, one or more of carbon and titanium nitride oxide as a dispersed phase forming component: 1 to 20%, A, 4N as a dispersed phase forming component: 0.1 to 5.0%, If necessary, one or more Cr group metals as a bonding phase-forming component: 1 to 20, one or two or more iron group metals as a bonding phase-forming component, and unavoidable It is characterized by having a component composition consisting of two impurities and a remainder nine.

Next, in the cermet of the present invention, the reason for directly limiting the number as described above will be explained.

(a) Due to the inclusion of C/NN in the multiple solid carbonitride, the multiple solid carbonitride exhibits a grain growth suppressing effect during sintering, and as a result, the produced cermet has good thermal shock resistance and plastic deformation resistance. Although the quality is improved, C/
If N is 1 or less, that is, if the amount of N relative to C becomes too large, the wettability of the plural solid carbonitrides with the binder phase decreases, so the C/N was set to be 1 or more.

(b) Amount of substitution of the above-mentioned substitution component in the multi-hard carbonitride A multi-hard carbonitride made of titanium carbonitride in which part of the Ti is replaced with the above-mentioned substitution component has excellent wettability with the binder phase. , a cermet containing this as the main dispersed phase has excellent high-temperature strength, but if the amount of substitution is 10
If the substitution amount is less than 70%, the desired wettability improvement effect cannot be ensured, while if the substitution exceeds 70%, the oxidation resistance and wear resistance of the produced cermet will deteriorate. The amount of substitution was determined to be 10-70%.

(C) Content of multiple solid solution carbonitrides - If the content is less than 50%, the desired wear resistance cannot be secured, while if the content exceeds 95%, the content of the binder phase is If the fx9 is relatively low, the bore (/''L) will remain in the cermet and the toughness will decrease, so the content was determined to be between 50 and 95.

(a) If the content of carbon/titanium nitride is less than 1%, the desired effect on spheroidization and grain growth suppression of multiple solid carbonitride particles cannot be obtained;
If the content exceeds 0, the wettability of the dispersed phase with the binder phase will be significantly reduced, leading to the formation of many bores in the therme solution, and as a result, the toughness will be reduced. Since K, its content was determined to be 1 to 20%.

(e) AtN If the content is less than 0.1%, the desired effects described above cannot be obtained, while if the content exceeds 5.0%, the wettability of the dispersed phase to the binder phase deteriorates. Therefore, the content meter was set at 0.1 to 5.0.

(f) Content of Cr group metals As mentioned above, these components K are dissolved in iron group metals to further improve the high-temperature strength of the cermet, and further improve the wettability with the dispersed phase during sintering. However, if the content is less than 1%, the desired effect cannot be obtained, while if the content exceeds 20%, the wear resistance and toughness of cermet will decrease. Therefore, its content was determined to be 1 to 20%.

Next, the cermet of the present invention will be explained using examples and comparing with comparative examples.

The raw material powders were blended to have the cermet composition shown in Table 1, and this blended powder was wet mixed in a ball mill, dried, and then press-molded into a green compact at a pressure of 800 kg/crrL2. Next, the green compact is IO”mmHg.
in vacuum, temperature VC within the range of 1400-15000G
Cermets 1 to 25 of the present invention and comparative cermets 1 to 5 were manufactured by sintering under conditions of holding for 1 hour.

In addition, comparative cermets 1 to 4 contain a plurality of solid carbonitrides, which are out of the scope of the present invention, as a replacement component, and comparative cermet 5 does not contain carbon, titanium nitride oxide, or AtN. It is something.

The Rockwell hardness (A scale) and transverse rupture strength of the resulting cermets 1 to 25 of the present invention and comparative cermets 1 to 5 were measured, and from this, the CIS
-Cut out a cutting tip with the shape of SNP432, work material: JIS-SNCM-8 (hardness: HB270),
Cutting speed: 158m/min, feed: 0.7 3mi/ r e v r depth of cut:
1.5 mm, cutting time: 10 min. Dry continuous cutting test under the conditions of and Work material: JIS-SNCM-8 (Hardness: HB27
0), cutting speed: 100 m/min, feed: 0.3 mml r ev, depth of cut: 1.5 mm, cutting time: 5 min. The width of the flank wear and the depth of the rake wear were measured, and in the latter intermittent cutting test, the number of fractures among the 6 cutting edges tested was measured.

These results are also shown in Table 1.

From the results shown in Table 1, the present invention cermets 1 to 25
All of the cermets have high hardness and high toughness, and therefore show excellent wear resistance and impact resistance in cutting tests, whereas Comparative Cermets 1 to 5 have at least one of hardness and toughness. As a result, it is clear that it does not exhibit satisfactory cutting performance even in cutting tests.

As mentioned above, the cermet of the present invention has high hardness and toughness, and also has excellent oxidation resistance, so it has excellent wear resistance especially when used as a cutting tool that requires these properties. It exhibits excellent cutting performance when used not only for turning but also for milling.

Claims (1)

[Claims] 1. As a dispersed phase-forming component, C/N>l"Y is present, and a portion of Ti in titanium carbonitride is contained in a range of 10 to 70, excluding Ti in 4a of the periodic table. Multiple solid carbonitrides consisting of those substituted with one or more of r 5 a + and group 6a metals: 50 to 95%, titanium carbonate, titanium nitoxide, also as dispersed phase forming components; and one or more of titanium carbonitride oxide: 1 to 20%, aluminum nitride as a dispersed phase forming component.
1 to 5.0%, one or two iron group metals as a binder phase forming component
A tough cermet containing oxygen, characterized by consisting of certain and unavoidable impurities: residue (weight ratio). 2 As a dispersed phase forming component, having C/N > 1, a part of Ti in titanium carbonitride, 4 a r 5 a + and 6 a of the periodic table excluding Ti, in the range of 10 to 70 Multiple solid carbonitrides consisting of those substituted with one or more of group metals = 50 to 95%, titanium carbonate, titanium nitride oxide, and titanium carbonitride oxide as dispersed phase forming components. One or more of these: 1 to 20 cm, and aluminum nitride as a dispersed phase forming component.
1 to 5.0%, one or two of the Cr group metals as a bond-forming component
Oxygen-containing toughness characterized by consisting of: 1 to 20%, one or more iron group metals as binder phase-forming components, and the remaining unavoidable impurities (by weight) cermet.