JPH09309008A - Throwaway cutting tip excellent in defect resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To display excellent cutting performance in even continuous cutting and interrupted cutting over a long period, by brazing a cutting edge member of triangle pyramid-shaped cubic system boron nitride group sintered material to a notched part formed in a triangular surface by obliquely cutting a corner part of tungsten carbide group hard metal support member. SOLUTION: A throwaway cutting tip excellent in defect resistance is formed by brazing a cutting edge member 1 of cubic system boron nitride group sintered material having a triangle pyramid shape to a notched part formed in a triangular surface by obliquely cutting a corner part of a tungsten group hard metal support member 2 by bronze 3. In this way, stress generated at cutting time is absorbed by the brazing part 3 directly connected to the support member 2, so as to remarkably decrease residual stress in the cutting edge member 1, its defect resistance is markedly improved. Accordingly, even in continuous and interrupted cutting, excellent cutting performance is displayed over a long period, to be made capable of largely contributing to FA generation and labor saving in cutting work.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has excellent fracture resistance, and therefore N, such as cast iron and Inconel.
The present invention relates to a throwaway cutting tip that exhibits excellent performance over a long period of time even when used for intermittent cutting of i alloy.

[0002]

2. Description of the Related Art Conventionally, generally, for example, Japanese Patent Laid-Open No. 3-170.
No. 206 publication and as shown in a schematic perspective view in FIG. 2, an upper layer 1a of a cubic boron nitride (hereinafter referred to as cBN) based sintered material and a tungsten carbide (hereinafter referred to as WC) based cemented carbide. A throwaway cutting tip formed by brazing 3 a cutting edge member 1 made of a two-layer composite sintered body of an alloy lower layer 1b to a stepped notch formed in a corner portion of a support member 2 of WC-based cemented carbide. It has been known. It is also known that the above conventional throwaway cutting tip is used for continuous cutting of various cast irons and Ni-based alloys.

[0003]

On the other hand, in recent years, FA has been remarkably changed to cutting in recent years, and there is also a strong demand for labor saving. Accordingly, the cutting tool can be applied not only to continuous cutting but also to intermittent cutting. However, although the conventional slow-away cutting tip described above exhibits excellent cutting performance in continuous cutting, it is prone to chipping or chipping in the cutting edge in intermittent cutting, so it can be used in a relatively short time. The current situation is that it reaches the end of its life.

[0004]

Therefore, the inventors of the present invention have paid attention to the above-mentioned conventional throwaway cutting tip from the above viewpoints, and have conducted research to make it applicable to intermittent cutting. As a result, in the above conventional throwaway cutting tip, the cutting blade member has a two-layer composite sintered body structure, that is, a structure in which the upper layer of the cBN-based sintered material is integrally and firmly fixed by the lower layer of the WC-based cemented carbide. Therefore, it is unavoidable that stress remains in the upper layer of the cBN-based sintered material particularly in interrupted cutting where high stress is generated, and this residual stress easily causes chipping or chipping of the cutting edge. However, as shown in the schematic perspective view of FIG.
Is formed into a triangular pyramid shape, and is composed only of a cBN-based sintered material, and this cutting blade member is formed into a triangular surface by diagonally cutting the corner portion of the support member 2 of WC-based cemented carbide. When the structure is brazed to the portion (3), the stress generated in the cutting blade member during cutting is absorbed by the brazing portion that directly joins the cutting blade member to the supporting member, so that the residual stress in the cutting blade member is significantly increased. We obtained the research results that the fracture resistance of the cutting edge is dramatically improved because the size becomes smaller.

The present invention has been made on the basis of the above-mentioned research results, and a cutting blade member of a cBN-based sintered material having a triangular pyramid shape and a corner portion of a support member of a WC-based cemented carbide are slanted. It is characterized by a throwaway cutting tip having excellent fracture resistance, which is obtained by brazing the cutout portion into a triangular surface by brazing.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the throwaway cutting tip of the present invention will be specifically described by way of examples. First,
As raw material powders, cBN powder, TiC powder, TiN powder, TiCN powder, TiB ₂ powder, TaC powder, NbC, each having a predetermined average particle size within the range of 1 to 10 μm
Powder, VC powder, HfC powder, Al ₂ O ₃ powder, and AlN powder were prepared, and these raw material powders were blended to the blending composition shown in Table 1, wet-mixed in a ball mill for 72 hours, dried, and then dried at 200 MPa. At pressure of, diameter: 2
Of the conventional throwaway cutting tip having the dimensions of 0 mm × thickness: 2 mm, the compacts A to C for forming the cutting blade member of the throwaway cutting tip of the present invention, and the diameter: 20 mm × thickness: 2 mm Each of the green compacts D to F for forming the cutting blade member was press-molded. Then, the green compacts A to C were used as they were, and the green compacts D to F were each composed of WC-6 wt% Co and the diameter was 2
0 mm x thickness: 2.5 mm, WC-based cemented carbide chips are stacked on top of each other and put into a normal belt type ultra-high pressure sintering machine, pressure: 6 GPa, temperature: 1350
Ultra-high pressure sintering under conditions of ° C, and after sintering into four fan-shaped sections, the cutting blade members A to C for slow-away cutting tips of the present invention consisting only of the cBN-based sintered material and the cBN-based sintered material. Cutting edge members DF for conventional throwaway cutting tips each having a two-layer composite sintered body structure of an upper layer and a lower layer of a WC-based cemented carbide were manufactured.

Further, as a support member of WC-based cemented carbide,
Each of them is composed of a sintered body having a blending composition shown in Table 2, and each has a triangular planar shape and has dimensions of one side length: 4 mm x thickness: 1.5 mm, and the corner portion is cut off obliquely. The supporting members a to d of the present invention for forming a throwaway cutting tip formed by forming a notch of a triangular surface having a side length of 3.4 mm, and the above-mentioned conventional blade members for cutting a throwaway cutting tip D to F at the corners. The conventional throwaway cutting tip supporting members e to g each having a stepped notch having a size corresponding to the above were prepared. Further, as a brazing material, a plate-shaped brazing material having a thickness of 0.35 mm, which is made of an Ag alloy having the composition shown in Table 3, respectively.
I prepared u.

Next, in the cutout portion of the support member,
With the combinations shown in Table 4, place the cutting blade members with the brazing filler metal sandwiched therebetween, and in a vacuum of 1 × 10 ⁻³ torr at 950 ° C.
Brazing under the condition of holding for 5 minutes, followed by grinding to obtain the shape of JIS TNMA332, the throwaway cutting tips of the present invention (hereinafter referred to as the present tips) 1 to 5 and conventional throws. Away cutting chips (hereinafter referred to as conventional chips) 1 to 3 were manufactured.

[0009]

[Table 1]

[0010]

[Table 2]

[0011]

[Table 3]

[0012]

[Table 4]

Next, the chip 1 of the present invention obtained as a result of this
~ 5 and conventional chips 1 to 3, work material: JIS / FC250 (pearlite cast iron) round bar, cutting speed: 700 m / min. Incision: 0.3 mm. , Feed: 0.15 mm / rev. , Cutting time: 60 minutes, wet continuous cutting test of cast iron under the following conditions: Work material: JIS / FC250, 4 longitudinally equidistant round bars with V groove, Cutting speed: 300 m / min. Notch: 0.25 mm. , Feed: 0.3 mm / rev. , Cutting time: 30 minutes, wet intermittent cutting test of cast iron under the following conditions, and work material: Inconel 718 (Ni-based alloy) with four equally spaced V-shaped round bars in the longitudinal direction, cutting speed: 100 m / min. Incision: 0.5 mm. , Feed: 0.3 mm / rev. Cutting time: 20 minutes, a wet interrupted cutting test was performed on the Ni-based alloy, and the flank wear width of the cutting edge was measured in each cutting test. The results of these measurements are shown in Table 4.

[0014]

From the results shown in Table 4, the chips 1 to 5 of the present invention exhibit excellent cutting performance in both continuous cutting and interrupted cutting, while the conventional chips 1 to 3 show excellent cutting performance in continuous cutting. It has the same excellent performance as Chips 1-5, but it is difficult to put it into practical use because intermittent cutting causes chipping of the cutting edge and reaches the end of its useful life in a relatively short time. is there. As described above, the throwaway cutting tip of the present invention exerts excellent cutting performance in both continuous cutting and interrupted cutting for a long period of time, and therefore contributes greatly to FA cutting and labor saving. It has industrially useful properties.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a throwaway cutting tip of the present invention.

FIG. 2 is a schematic perspective view of a conventional throwaway cutting tip.

[Explanation of symbols]

 1 Cutting blade member 2 Support member 3 Brazing

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[Procedure amendment]

[Submission date] June 26, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

[0014]

From the results shown in Table 4, the chips 1 to 5 of the present invention exhibit excellent cutting performance in both continuous cutting and interrupted cutting, while the conventional chips 1 to 3 show excellent cutting performance in continuous cutting. While exhibiting excellent performance comparable to the chip 1-5, the intermittent cutting chipping the cutting edge occurs, so leading to a relatively short time service life, it is clear that for practical use is difficult is there. As described above, the throwaway cutting tip of the present invention exerts excellent cutting performance in both continuous cutting and interrupted cutting for a long period of time, and therefore contributes greatly to FA cutting and labor saving. It has industrially useful properties.

Claims (1)

[Claims] 1. A cutting edge member made of a cubic boron nitride-based sintered material having a triangular pyramid shape is cut into a triangular surface by cutting a corner portion of a supporting member made of a tungsten carbide-based cemented carbide obliquely. A throwaway cutting tip with excellent fracture resistance that is brazed.