JPS6112963B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a composite sintered material having excellent toughness and heat and wear resistance, and which is suitable for use by being attached to the cutting edge of a cutting tip, especially when cutting difficult-to-cut materials. It concerns pieces.

Traditionally, nonferrous metal materials such as Al and Al alloys, Cu and Cu alloys, plastics, rubber,
For drilling and high-speed finishing cutting of non-metallic materials such as graphite and ceramics, a cutting edge layer of diamond-based sintered material with the same wall thickness,
A composite sintered piece with an equal-thickness laminated structure consisting of a two-layer composite with a retaining layer of tungsten carbide (hereinafter referred to as WC)-based cemented carbide is attached to the cutting edge by brazing the diamond-based sintered material. A cutting tip is used which is mounted with the cutting edge layer positioned at the top.

However, in the above-mentioned conventional composite sintered piece, the retaining layer constituting it is exposed on the flank when attached to the cutting edge of the cutting tip, and does not have sufficiently satisfactory toughness. At the interface between the cutting edge layer and the holding layer, abnormally elongated grain growth of WC grains occurs during sintering, and this causes the interfacial bonding strength between the cutting edge layer and the holding layer to deteriorate. Therefore, when this material was subjected to cutting, there was a problem in that it did not exhibit desired and satisfactory cutting characteristics.

From the above-mentioned viewpoint, the present inventors conducted research to solve the problems of the above-mentioned conventional composite sintered pieces for cutting edges of cutting chips. It is made of special steel that has good bondability with diamond-based sintered materials such as steel and alloy tool steel, and has high toughness.However, in this case, the part that becomes the flank when attached to the cutting edge of the cutting tip If the special steel is exposed on the flank surface, the heat and wear resistance of the flank surface during cutting will be significantly reduced. When the section is made into an uneven thickness laminated structure consisting of a cutting edge layer of diamond-based sintered material, the resulting composite sintered piece has extremely high interfacial bonding strength between the cutting edge layer and the retaining layer, and has high toughness. They found that it has excellent heat and abrasion resistance.

Therefore, the present invention has been made based on the above knowledge, and provides that the composite sintered piece attached to the cutting edge of the cutting tip has a cutting edge layer made of a diamond-based sintered material and a cutting edge layer made of special steel. The uneven thickness laminated structure is composed of a two-layer composite with a retaining layer, and the portion that becomes the flank and rake face when attached to the cutting edge of a cutting tip is occupied by the cutting edge layer of diamond-based sintered material. It is characterized by having the following.

Next, the composite sintered piece of the present invention will be explained with reference to examples.

Example 1 Fe powder with an average particle size of 4.5 μm: 73.5%, 3.0%
μm Cr powder: 18%, 0.6 μm Mo powder: 3
%, 0.7 μm W powder: 3%, 5.0 μm V powder: 1%, and 0.3 μm carbon powder: 1.5%
From a mixed powder consisting of (more than 1% by weight), 1.0ton/
It has dimensions of 12 mmφ in diameter x 3.0 mm in thickness under a pressure of cm ² , and has a shape shown in the perspective view in Figure 1, that is, a center depth of 3.0 mm formed by cutting with the tip of the drill bit.
A compacted powder piece 1 for forming a retaining layer having a conical recess 1a of mm is prepared, this compacted powder piece 1 is charged into a cylindrical thin-walled container made of Zr, and the average particle diameter 0.5μm diamond powder: 95% by volume, 1.2%
After charging and filling 60mg of mixed powder for forming a cutting edge layer consisting of 5% by volume of μm Co powder, the entire container was inserted into a normal ultra-high pressure and high temperature generator, and the pressure: 55kb, temperature: 1400 ℃, holding time: 30 minutes, and after sintering, slowly cooled to 1300℃, then rapidly cooled, and finally held at 600℃ for 15 minutes to harden the retaining layer. The composite sintered piece material T of the present invention was manufactured by applying the following treatment.

The resulting composite sintered piece material T of the present invention
has dimensions of 12 mmφ in diameter x 2.5 mm in thickness, and as shown in the longitudinal cross-sectional view in Fig. 2, the cutting edge layer A is made of diamond-based sintered material and high-speed steel (JIS/
It consisted of an uneven thickness laminated composite with a retaining layer B (corresponding to SKH-9).

In addition, for the purpose of comparison, the shape of the compacted powder piece 1' for forming the retaining layer was assumed to be a disk shape as shown in the perspective view in Fig. 3, and its dimensions were 12 mmφ x thickness: 2.0 mm.
Except for mm, the above-mentioned composite sintered piece material T of the present invention
Under the same manufacturing conditions as the manufacturing conditions of
The wall thickness of A′ is 0.5 mm, and the wall thickness of retaining layer B′ is 2.0 mm.
A comparative composite sintered piece material T′ was produced.

Furthermore, for the purpose of comparison, the composition of the mixed powder for forming the retention layer was the same as above, except that the composition was 94% by volume of WC powder with an average particle size of 1.0 μm and 6% by volume of Co powder with an average particle size of 1.5 μm. Under the same manufacturing conditions as the comparative composite sintered piece material T', the same cross-sectional structure as the comparative composite sintered piece material T' shown in FIG. 4, that is, the cutting edge layer of the diamond-based sintered material A″ and WC
Manufacture a conventional composite sintered piece material T'' with an equal thickness laminated structure consisting of a two-layer composite with a retaining layer B'' of base cemented carbide, each having a uniform thickness of 0.5 and 2.0 mm. did.

Next, the above-mentioned composite sintered piece material T of the present invention, comparative composite sintered piece material T', and conventional composite sintered piece material T'' were each equally divided into four pieces as shown in the perspective view of FIG. After dividing into the present invention composite sintered piece P, comparative composite sintered piece P', and conventional composite sintered piece P'', as shown in the plan view in FIG. 6, the planar dimensions are: 127mm□×Thickness: 4.8mm WC-based cemented carbide cutting tip (throw-away tip) H
In the case of the composite sintered piece P of the present invention, the flank face f and the rake face C are diamond-based sintered, as shown in a partial perspective view in FIG. The cutting edge layer A of the material is occupied by the diamond-based sintered layer A, while the comparative composite sintered piece P′ and the conventional composite sintered piece P″ have diamond-based sintered With the cutting edge layers A′ and A″ of the bonding material positioned on top, solder is applied using silver solder, and this is further attached to the cutting tool. Then, workpiece material: aluminum cast iron, cutting speed:
200m/min, feed: 0.1mm/rev, depth of cut: 0.5
mm, cutting oil: A cutting test was performed in which holes were drilled under the conditions of use, and the number of holes machined and the finished surface roughness of the machined holes until the end of the service life were measured.

As a result, the composite sintered piece P of the present invention reached the end of its service life due to normal wear after machining 2500 pieces, and also exhibited excellent cutting characteristics with a hole finish surface roughness of 2S, while the flank face f was cut at high speed. The comparison composite sintered piece P′, in which the steel retaining layer B′ is exposed, reached its lifespan after 6000 pieces and had a poor hole finish surface roughness of 7s, and the conventional composite sintered piece P″ also suffered from chipping. with 20000
It reached the end of its service life, and its finished surface roughness was 4s.

Example 2 The distribution ratio of the mixed powder for forming the retention layer was 84% for Fe powder with an average particle size of 4.0 μm, and 84% for Cr powder with an average particle size of 5.0 μm.
Powder: 10%, 0.7 μm Mo powder: 4%, 6.0
The present invention of Example 1 above except that the V powder of μm: 1% and the carbon powder of 0.3 μm: 1% (more than 1% by weight), and the slow cooling end temperature after sintering was 1100 ° C. Under the same manufacturing conditions as the composite sintered piece P, a cutting layer of diamond-based sintered material and a retaining layer of alloy tool steel (equivalent to JIS/SKD11) were combined.
A composite sintered piece of the present invention consisting of a layer composite and having a laminated structure with uneven thickness was manufactured.

The resulting composite sintered piece of the present invention was attached to a cutting tip in the same manner as in Example 1, and this was further attached to a cutting tool. Work material: Al-13%Si alloy, cutting speed: 600 m/min. , feed: 0.1mm/rev,
A cutting test was conducted under the condition that the depth of cut was 0.5 mm, and the cutting time until the flank wear width reached 0.2 mm was measured.

Further, cutting tests were also conducted on the comparative composite sintered piece P' produced in Example 1 and the conventional composite sintered piece P'' under the same conditions.

As a result, the composite sintered piece of the present invention reached the specified amount of wear due to normal wear after a cutting time of 145 minutes, whereas the comparative composite sintered piece P′ reached the specified amount of wear in 18 minutes, and the conventional composite sintered piece Each piece P″ reached a predetermined amount of wear in 15 minutes.

As mentioned above, in the composite sintered piece of the present invention, the retaining layer is made of special steel that has significantly superior toughness compared to WC-based cemented carbide and high interfacial bonding strength with diamond-based sintered material, In addition, the cutting edge layer is made of a diamond-based sintered material, and when attached to the cutting edge of the cutting tip, the cutting edge layer has a laminated structure with uneven thickness that occupies the flank and rake surfaces, so it has excellent toughness. Therefore, when it is attached to the cutting edge of a cutting chip and used for cutting difficult-to-cut materials, it exhibits extremely excellent cutting performance.

[Brief explanation of the drawing]

FIGS. 1 and 3 are perspective views showing compacted powder pieces;
Figures 2 and 4 are longitudinal sectional views showing the composite sintered piece material, Figure 5 is a perspective view showing how the composite sintered piece is divided, and Figure 6 is a cutting tip of the composite sintered piece. FIGS. 7 and 8 are a plan view showing how the cutting tip of the composite sintered piece is attached to the cutting edge, and a partial perspective view showing how the cutting tip of the composite sintered piece is attached to the cutting edge. 1,1'...Powder compact piece, T...Composite sintered piece material of the present invention, T'...Comparative composite sintered piece material, T''...
...Conventional composite sintered piece material, A, A', A''... Cutting edge layer, B, B', B''... Holding layer, P... Composite sintered piece of the present invention, P'... Comparison Composite sintered piece, P″... conventional composite sintered piece, H... cutting tip, f... flank face, C... rake face.

Claims (1)

[Claims] 1. A composite sintered piece to be attached to the cutting edge of a cutting tip, this composite sintered piece is composed of a two-layer composite of a cutting edge layer of diamond-based sintered material and a retaining layer of special steel, And the part that becomes the flank and rake face when attached to the cutting edge of the cutting tip,
A composite sintered piece for a cutting edge of a cutting tip, characterized in that it has an uneven thickness laminated structure occupied by the cutting edge layer of the diamond-based sintered material.