JPS6015594B2 - Cutting blade for cutting tools - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cutting blade for a cutting tool that has excellent toughness and heat and wear resistance, and is particularly suitable for use as a cutting blade when cutting difficult-to-cut materials. .

For high-speed finishing cutting of non-ferrous metal materials such as steel, AI and AI alloys, Cu and Cu alloys, and non-metallic materials such as plastics, rubber, graphite, and ceramics, the cutting edge layer of diamond-based material and A two-layer composite sintered body with a retaining layer made of tungsten carbide (hereinafter referred to as WC)-based cemented carbide is used as a cutting edge for the purpose of imparting grade to this.

The above-mentioned cutting blades for conventional cutting tools are usually manufactured under ultra-high pressure conditions such as pressure: 5 to 6 atmospheres and temperature: 1350 to 1500 pm. It will be liquid phase sintered.

In the retaining layer of such a cutting edge for a conventional cutting tool, a considerable amount of WC is dissolved in the liquid phase (usually composed of Co) under high temperature and high pressure during manufacturing, while a proportionate amount of WC is dissolved in the liquid phase (usually composed of Co). As WC precipitation becomes more active during solidification, the precipitated WC grains grow abnormally long and thin.
The growth of these WC grains is particularly likely to occur at the interface with the cutting edge layer where there is a significant carbon concentration gradient, and as a result, there is a problem that the interfacial bonding strength between the cutting edge layer and the retaining layer is poor. In conventional cutting tool cutting edges where the adhesion between the cutting edge layer and the retaining layer is not good, the minute vibrations generated during cutting are amplified, which accelerates the progress of wear on the cutting edge. Furthermore, chipping and defects were more likely to occur. From the above-mentioned viewpoints, the present inventors have developed a cutting edge for a cutting tool that has high interfacial bonding strength with the diamond-based crystalline material constituting the cutting edge layer, and has excellent grain hardness and heat and wear resistance. As a result of research to obtain a retaining layer forming material, it was found that if the above retaining layer forming material was nitrided and composed of an elemental (hereinafter referred to as Si3N4) based ceramic, the inside of the retaining layer would be Of course,
Grain growth is also accelerated at the interface with the cutting edge layer, ensuring a homogeneous microstructure, and therefore a cutting tool for cutting tools with high interfacial bonding strength with the cutting edge layer made of diamond-based bonded material. Obtaining a blade.

[b} The diamond-based material that constitutes the cutting edge layer of the cutting edge for cutting tools is ■ Diamond: 92 to 97% by volume.
, One or more Fe group metals and unavoidable impurities: Remaining ■ Diamond: ~97% by volume, Si alloy and unavoidable impurities: Remaining ■ Diamond: 60~9% by volume, Periodic table Carbides and urides of umbrella and insect group metals, as well as aluminum nitride (hereinafter referred to as AIN), poppy carbide/silicon carbide (hereinafter referred to as SIC), poppy nitride, and nitride (hereinafter referred to as Si)
3N4), furthermore, one or more of the group consisting of these solid solutions and unavoidable impurities: the remaining component composition is determined to be any of the above (■ to ■), while,
The Si3N4-based condensed ceramic that makes up the retention layer is
■ Si3N4: 90 to 97% by volume, one or more of magnesium oxide (hereinafter referred to as Mg○), aluminum oxide (hereinafter referred to as AI203), and yttrium oxide (hereinafter referred to as Y2Q), and inevitable impurities: Remaining, ■ Si3N4: mottled to 97% by volume, one or more of iron group metals and Si, and unavoidable impurities: remaining, @ Si3N4: 70 to 9
7% by volume, one or more of NN, titanium nitride (hereinafter referred to as TIN), and Sialon (having the general chemical formula: SiAI×Nz): the remainder, the component composition of any of the above ■ to ■ The cutting tool blade, which is constructed by appropriately combining a special blade layer and a retaining layer that have a specified component composition, has particularly high interfacial bonding strength and exhibits extremely excellent cutting performance during cutting. To demonstrate.

The findings shown in {a' and 'b' have been obtained above.

This invention has been made based on the above findings, and furthermore, the cutting edge for a cutting tool of this invention can be manufactured using a known ultra-high pressure and high temperature generator by a normal powder waste method. .

That is, the cutting edge for a cutting tool of the present invention is obtained by cold compression from a mixed powder for forming a cutting edge layer and a retaining layer, which are blended and mixed so that each has a predetermined final component composition. Form the green compacts separately so that they have approximately the same shrinkage rate, 'b' If necessary, both green compacts formed in the above {a) step are pre-frozen at a temperature of 1200 oo or less,
Z'c - The above-mentioned compacted powder or both temporary bodies are charged into a container in a combined state, heated and deaerated, and then sealed, It can be manufactured by a basic process consisting of obtaining a two-layer composite compact in which the cutting edge layer and the holding layer are tightly integrated into one by sintering in an ultra-high pressure and high temperature generator.

Next, the cutting blade for a cutting tool according to the present invention will be explained with reference to examples.

2 Examples 1 From a mixed powder for forming a cutting edge layer consisting of 9 group volume % of synthetic diamond powder with an average particle size of 1 deviation and 2 volume % of Si-Co alloy (Si: 15 weight % contained) powder. A powder compact with dimensions 2 of 6 diameter side 0 x thickness 1 rib was formed using small pressure, while Q-Si3N4 powder with average particle size 0.8 deviation: 9 string volume%
and Si-Co alloy (Si: containing 15% by weight) powder: A green compact was formed under the same conditions from a mixed powder for forming a retaining layer, and the thus formed compacted powder was heated with N.
Loaded into three cylindrical containers made by J and placed in a vacuum furnace at a temperature of 7.
After heating and degassing under the conditions of 00℃ and pressure: 104 tons,
It is sealed by welding a Ni upper cover, and then the encapsulated compressed powder body is charged into a belt-type ultra-high pressure and high temperature generator,
The cutting blade for a cutting tool of the present invention is manufactured by sintering under the conditions of pressure: 60 Kb, temperature 140,000, and holding time: 30 minutes, which is made of a two-layer composite sintered mackerel body in which the cutting blade layer and the retaining layer are integrally joined. did.

The resulting cutting edge for a cutting tool of the present invention was polished with a diamond wheel and the structure was observed.4 As a result, both the cutting edge layer and the holding layer had a theoretical density ratio of 100%, and the holding layer Abnormal growth of grains was not observed at all not only in the interior but especially at the interface with the cutting edge layer, and the specimen had a very fine structure.

Further, the above-mentioned retaining layer exhibited a Vickers hardness of 1700k9/poor. On the other hand, for the purpose of comparison, a cutting tool for a comparative cutting tool was manufactured under the same manufacturing conditions as the cutting edge for a cutting tool of the present invention, except that the retaining layer was made of a cemented carbide having a composition of WC-6% by weight Co. Manufactured the blade.

Next, the cutting edges for both cutting tools were attached to the cutting edges of WC-based cemented carbide cutting tips (throw-away tips) by brazing, and then these were attached to the cutting tool, and the workpiece material: FC- 25 (Brinell hardness HB: 220), Cutting speed: 200m/skin, Feed: 0.1 pig/rev Depth of cut: 1. External turning test was conducted under the following conditions without using cutting oil and the flank wear was 0.
The cutting time until reaching one fence was measured.

As a result, the cutting tip to which the cutting edge for the cutting tool of the present invention was attached reached the specified wear amount in 35 minutes due to normal wear, whereas the tip to which the cutting edge for the comparative cutting tool was attached caused chipping and reached the specified wear amount in 2 minutes. The amount of wear reached the predetermined amount. Example 2 Substantially the same composition as in Example 1 above, except that the blending ratio of the mixed powder for forming the cutting edge layer and the retaining layer was as shown in Table 1. Each of the present invention a to k having a final component composition was manufactured.

All of the resulting inventive materials a to k' of the present invention had a fine structure, and the interface between the cutting edge layer and the holding layer showed good adhesion.

Next, the same comparison as that prepared for the purpose of comparison in the above inventions a to k and Example 1 was attached to the cutting edge of the cutting tip by brazing, and this was further attached to the cutting tool, and the workpiece material: FC -25 (Brinell hardness HB: 220), Cutting speed: 200/rev, Feed: 0.1 leg/rev, Depth of cut: 1. A cutting test was conducted under the following conditions, and the cutting time until the flank wear reached 0.15 ribs was measured.

The measurement results are shown in Table 1 along with the state of the cutting edge.
As shown in Table 1, the cutting blades a to k for the cutting tool of the present invention
All of these have low interfacial bonding strength, so they reached the end of their life after securing an extremely long cutting time due to normal wear, whereas the cutting edge of the comparative cutting tool has a cutting edge layer and a retaining layer. Since the strength of the interfacial bond with the material was poor, chipping occurred and the life span was reached in a relatively short period of time. In addition, in the above embodiment, a case was described in which the cutting edge for a cutting tool was attached to the cutting edge portion of a cutting tip made of a base cemented carbide. Of course, it may also be used as

Claims (1)

[Scope of Claims] 1. A cutting edge layer of a diamond-based sintered material containing 60 to 97% by volume of diamond, and a retaining layer of silicon nitride-based sintered ceramic containing 70 to 97% by volume of silicon nitride. A cutting blade for a cutting tool characterized by being made of a two-layer composite sintered body. 2. The above claim, wherein the diamond-based sintered material has a composition consisting of: 92 to 97% by volume of diamond, one or more Fe group metals, and the remainder of unavoidable impurities. The cutting blade for a cutting tool according to item 1. 3. The cutting blade for a cutting tool according to claim 1, wherein the diamond-based sintered material has a composition consisting of: 92 to 97% by volume of diamond, the remainder being Si alloy and unavoidable impurities. . 4 The diamond-based sintered material contains: Diamond: 60 to 97% by volume, carbides and nitrides of metals in groups 4a and 5a of the periodic table, aluminum nitride, silicon carbide, silicon nitride, and solid solutions thereof. The cutting edge for a cutting tool according to claim 1, characterized in that it has a composition consisting of one or more of the group consisting of: and the remainder unavoidable impurities. 5 The silicon nitride-based sintered ceramic has a composition consisting of: silicon nitride: 90 to 97% by volume, one or more of magnesium oxide, aluminum oxide, and yttrium oxide, and the remainder: unavoidable impurities. Claims 1 and 2 of the above claims are characterized in that:
The cutting blade for a cutting tool according to item 1, 3, or 4. 6. The silicon nitride-based sintered ceramic has a composition consisting of: silicon nitride: 88 to 97% by volume, one or more of iron group metals and Si, and the remainder: unavoidable impurities. A cutting blade for a cutting tool according to claim 1, 2, 3, or 4 above. 7. The silicon nitride-based sintered ceramic has a composition consisting of: silicon nitride: 70 to 97% by volume, one or more of aluminum nitride, titanium nitride, and sialon, and the remainder: unavoidable impurities. Claims 1, 2, and 3 of the above claims are characterized by:
Or the cutting blade for a cutting tool according to item 4.