JPH09108913A - Composite cutting tip whose cutting edge piece has excellent joining strength - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase joining strength of a cutting edge piece to a tip main body by directly brazing a cubic system baron nitride sintered material-made cutting edge piece to a cutting edge part of a tungsten carbide group cemented carbide-made tip main body through an Ni alloy brazing material. SOLUTION: A composite cutting tip contains Ti: 0.5 to 10% and/or Zr: 0.5 to 10%, and Cr: 5 to 20% in weight%, and also contains one kind or two or more kinds: 2 to 10 % among P, B and Si according to its necessity, and a residual part is formed by directly brazing a CBN sintered material-made cutting edge piece to a cutting edge part of a WC group cemented carbide-made tip main body by using an Ni alloy brazing material having the composition composed of Ni and unavoidable impurity. A component of Ti and Zr has an action which improves joining strength by further improving wettability to a tip main body of the brazing material and the cutting edge piece.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting edge of cubic boron nitride (hereinafter referred to as CBN) sintered material for a cutting edge portion of a tungsten carbide (hereinafter referred to as WC) -based cemented carbide chip body. The present invention relates to a composite cutting tip which has a high joining strength of pieces and therefore does not cause peeling of the cutting edge piece even when used for high speed cutting and exhibits excellent cutting performance for a long period of time.

[0002]

2. Description of the Related Art Conventionally, for example, JP-A-59-134665.
1 and in a schematic perspective view in FIG. 1, a cutting blade piece 3 made of a composite of a CBN sintered material layer 3a and a WC-based cemented carbide layer 3b is provided in a conventional ultra-high pressure sintering apparatus. Manufactured by using, for example, C at the cutting edge portion of the WC-based cemented carbide chip body in% by weight (hereinafter,% means% by weight).
A composite cutting tip having a structure in which u: 19%, Pd: 14%, Ti: 5%, and the rest are brazed using an Ag alloy brazing material having a composition of Ag and inevitable impurities is widely known. Which contains Cr and W as alloy components.
High hardness Co-based alloy (Stellite) containing a high proportion of
It is also known to be used for cutting such as.

[0003]

On the other hand, in recent years, cutting machines have been remarkably improved in performance, and there is a strong demand for labor saving in cutting. Accordingly, cutting tends to be speeded up. In the above-mentioned conventional composite cutting tip and many other composite cutting tips, when this is used for high-speed cutting, the brazing portion of the tip body and the cutting edge piece are each made of WC-based cemented carbide. Although there is no problem in joining, since the joining strength between the CBN sintered material layer and the WC-based cemented carbide layer is insufficient, peeling easily occurs from this portion, and the service life is reached in a relatively short time. Is the current situation.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above viewpoint, a brazing filler metal that can be brazed directly to the cutting edge of the WC-based cemented carbide chip body with a strong bonding strength by constructing the entire cutting edge piece with a CBN sintered material. As a result of research for development, Ti: 0.5 to 10
% And / or Zr: 0.5 to 10%, Cr: 5 to 2
0%, and if necessary, one or more of P, B, and Si: 2 to 10%, and the balance N, which has a composition of Ni and inevitable impurities.
When the cutting edge piece of the WC-based cemented carbide chip body is directly brazed to the cutting edge portion of the WC-based cemented carbide chip body by using the i alloy brazing material, excellent joining is achieved between the chip body and the cutting edge piece. As a result, research has shown that the strength is ensured, and therefore the resulting composite cutting tip exhibits excellent cutting performance over a long period of time without peeling of the cutting edge piece even when it is used for high-speed cutting. Is obtained.

The present invention has been made based on the above-mentioned research results, and a cutting blade piece made of a CBN sintered material is
i: 0.5 to 10% and / or Zr: 0.5 to 10
%, Cr: 5 to 20%, and, if necessary, one or more of P, B, and Si:
A cutting edge formed by directly brazing to a cutting edge portion of a WC-based cemented carbide chip body through a Ni alloy brazing material containing 2 to 10% and the balance being Ni and inevitable impurities. The piece is characterized by a composite cutting tip having excellent bonding strength.

Next, the reason why the component composition of the Ni alloy brazing material constituting the composite cutting tip of the present invention is limited as described above will be explained. (A) Ti and Zr These components have the effect of further improving the wettability of the brazing material with respect to the chip body and the cutting edge piece, thereby improving the bonding strength, but their contents are each less than 0.5%. However, the desired effect cannot be obtained in the above-mentioned action, and on the other hand, if the content of each exceeds 10%, the strength of the brazed portion will be reduced, so that the content of each of the content is 0.5-0.5%.
It was set to 10%, preferably 5 to 7%.

(B) Cr The Cr component has the effect of improving the hardness of the brazing material, but if the content of Cr is less than 5%, the desired hardness-improving effect cannot be obtained, while the content of Cr is 20. %, The rollability will rapidly decrease, so the content should be 5 to 2
It was set to 0%, preferably 10 to 15%.

(C) P, B, and Si These components have the effect of lowering the melting point of the brazing material, thereby increasing the fluidity, and enabling brazing joining with a smaller amount of brazing material. Therefore, if the content is less than 2%, the desired effect on the above action cannot be obtained. On the other hand, if the content exceeds 1%, the strength of the brazed part decreases. Therefore, the content is defined as 2 to 10%, preferably 3 to 8%.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION As raw material powder, average particle diameter: 5 μ
m and purity: 99.95% hexagonal boron nitride powder was used, and this was pressed into a green compact at a pressure of 1 ton / cm ² , and this green compact was applied to an ordinary belt type ultra-high pressure sintering device. Charge, pressure: 7 GPa, temperature: 2200 ° C, holding time: 3
Sintering was performed for 0 minutes to form a CBN sintered material having a diameter of 10 mmφ and a thickness of 2 mm, which was then cut with an ultrasonic cutter to a thickness of 1.9 mm and a side length. A cutting edge piece was manufactured by processing into a 5 mm regular triangle.

As the raw material powder, the average particle diameter is 3 μm.
WC powder and Co powder of 4 μm were mixed in a predetermined ratio, wet mixed in a ball mill for 72 hours, dried, and then pressed into a green compact at a pressure of 1 ton / cm ² , This green compact was sintered in a vacuum of 1 × 10 ^-3 torr and kept at 1400 ° C. for 1 hour to obtain TNGA.
₃ 32 (thickness: In 3.18 mm, one side length 16mm equilateral triangle) to form a WC-based cemented carbide material having a shape and composition of WC-8% Co, and occupy this one corner A chip body was manufactured by forming an equilateral triangular counterbore having a depth of 1.4 mm and a side length of 5 mm in the cutting edge portion.

Furthermore, a Ni alloy molten metal and an Ag alloy molten metal having the component compositions shown in Tables 1 and 2 were prepared by a usual melting method, and each was cast into an ingot under normal conditions and hot-melted. Ni alloy brazing filler metal for composite cutting tip of the present invention (hereinafter referred to as brazing filler metal of the present invention) a to w having a thickness of 0.35 mm after being subjected to rolling and cold rolling, and conventional composite cutting tip A
A g-alloy brazing material (hereinafter referred to as a conventional brazing material) was manufactured.

Next, the cutting blade pieces are set in the chip body via the brazing filler metals a to w of the present invention, and pressed at a pressure of 1 kg / cm ² using a hot press to 1 × 1.
The composite cutting tips of the present invention (hereinafter, referred to as the present chips) 1 to 23 were manufactured by brazing and joining at a temperature of 1250-1350 ° C. for 5 minutes in a vacuum of 0 ⁻³ torr.

Further, for comparison purposes, the above hexagonal boron nitride powder, and the above WC powder and C are used as raw material powders.
o Composite powder with a mixed powder of O powder (Co powder content 8%) and a hexagonal boron nitride powder layer having a thickness of 2 mm and a mixed powder layer having a thickness of 1.5 mm. The body was press-molded at a pressure of 1 ton / cm ² , and the composite green compact was sintered and processed under the same conditions as those for the cutting edge piece made of the CBN sintered material described above. By manufacturing a composite cutting blade piece and brazing this composite cutting blade piece to the cutting edge portion of the WC-based cemented carbide chip body using the above conventional brazing material under the same brazing conditions. A conventional composite cutting tip (hereinafter referred to as a conventional tip) was manufactured.

Next, with respect to the various chips obtained as a result, a work material: a round bar of a Co-based alloy having a composition of Co-28% Cr-4% W-1% C, cutting speed: 300 m / min ., Depth of cut: 0.25 mm, feed: 0.05 mm / rev., Cutting time: 5 minutes, and a dry continuous high-speed cutting test was performed to measure the flank wear width of the cutting edge. Table 3 shows the results of these measurements.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

[Table 3]

[0018]

From the results shown in Table 3, since all of the chips 1 to 24 of the present invention have extremely high bonding strength of the cutting blade piece to the chip body, they can be cut even at high speed cutting of a Co-based alloy which is a difficult-to-cut material. The cutting edge exhibits excellent cutting performance without peeling, whereas the conventional tip peels between the CBN sintered material layer of the cutting edge and the WC-based cemented carbide layer in a relatively short time after the start of cutting. Occurs, and it is clear that the service life is reached. As described above, the composite cutting tip of the present invention has extremely high bonding strength to the tip body of the cutting blade piece,
Even when used for high-speed cutting, the cutting edge piece does not peel off, and therefore, it is possible to satisfactorily deal with high-speed cutting and labor saving.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a conventional composite cutting tip.

[Explanation of symbols]

 1 Chip Body 2 Ag Alloy Brazing Material 3 Cutting Edge Piece 3a CBN Sintered Material Layer 3b WC Based Cemented Carbide Layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area C04B 35/583 C04B 37/02 B 37/02 35/58 103Y

Claims (2)

[Claims] 1. A cutting edge piece made of cubic boron nitride sintered material,
%, Ti: 0.5-10% and / or Zr: 0.5-1
0%, Cr: 5 to 20%, and the rest is directly brazed to the cutting edge portion of the tungsten carbide based cemented carbide chip body through a Ni alloy brazing material having a composition of Ni and inevitable impurities. Composite cutting tip with excellent joining strength. 2. A cutting edge piece made of a cubic boron nitride sintered material,
%, Ti: 0.5-10% and / or Zr: 0.5-1
0%, Cr: 5 to 20%, and one or more of P, B, and Si: 2 to
A cutting edge piece obtained by directly brazing to a cutting edge portion of a tungsten carbide-based cemented carbide chip body through a Ni alloy brazing material containing 10% of Ni and the balance of Ni and inevitable impurities. A composite cutting tip with excellent joint strength.