JPH0335041B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] In this invention, the cutting edge is made of boron nitride (hereinafter referred to as BN)-based ultra-high pressure sintered material, and the supporting material that supports this is made of tungsten carbide (hereinafter referred to as WC).
It is composed of cermets such as base cemented carbide and titanium carbide (hereinafter referred to as TiC) base cermets, and can be used not only for continuous cutting of high-hardness steel such as die steel and high-speed steel, but also for intermittent cutting such as milling and end face cutting. This invention relates to a composite cutting chip that exhibits excellent cutting performance when used for cutting. [Conventional technology] Conventionally, cubic BN (hereinafter referred to as CBN) and hexagonal crystal
The main component is BN (hereinafter referred to as WBN), and TiC and
A cutting edge made of a BN-based ultra-high pressure sintered material containing TiN and Al ₂ O ₃ as binder phase forming components is sintered into a support material made of WC-based cemented carbide or cermet. It is well known that a composite cutting chip formed by simultaneous bonding exhibits excellent wear resistance when used as a cutting tool for continuous cutting of high-hardness steel. [Problems to be Solved by the Invention] However, although the above-mentioned conventional composite cutting chips exhibit excellent cutting performance in continuous cutting of high-hardness steel, they do not work well when used for interrupted cutting of high-hardness steel. Currently, the cutting edge tends to chip and cannot be put to practical use due to lack of reliability. [Means for Solving the Problems] Therefore, from the above-mentioned viewpoint, the present inventors proposed a method in which the cutting edge is made of a BN-based ultra-high pressure sintered material, while the supporting material is made of a WC-based cemented carbide or a cermet. We focused on the above-mentioned conventional composite cutting chip, which consists of , (a) When the above conventional composite cutting tip is used for interrupted cutting, the reason why chipping is likely to occur on the cutting edge is as follows.
Co contained as a binder phase forming component in the support material
Metal components such as Ni and Ni are diffused and infiltrated into the cutting edge during sintering of the cutting edge, and the high-temperature strength of the cutting edge infiltrated with metal components in this way is not only reduced during cutting, but also The infiltrated metal component and TiC contained as a binder phase forming component
This is thought to be due to the fact that a large difference in thermal expansion occurs between TiN and Al ₂ O ₃ , etc., making it easier for tensile stress to occur in the cutting edge. (b) Between the cutting edge and the supporting material of the conventional composite cutting chip mentioned above, the wettability to metal components such as Co and Ni is extremely low, and the softening and diffusion phenomenon does not easily occur during sintering of the cutting edge. Table 4a and
When a high melting point compound layer consisting of a nitride or carbonitride of a group 5a metal is interposed, the infiltration of the metal component from the support material to the cutting edge during sintering is significantly suppressed, resulting in a reduction in melting. Chips caused by immersed metal components will no longer occur on the cutting edge. (c) The high melting point compound layer particularly constitutes the cutting edge.
The bonding strength to the BN-based ultra-high pressure sintered material is low, but if a metal layer made of metals from groups 4a and 5a of the periodic table is interposed between them, this metal layer will
Since the bonding strength for both is extremely high, a strong bond is ensured between the cutting edge and the supporting material. The findings shown in (a) to (c) above were obtained. Therefore, the present invention has been made based on the above knowledge, and it provides a cutting blade made of a BN-based ultra-high pressure sintered material that meets the requirements of 4a of the periodic table.
and a metal layer consisting of a group 5a metal,
Consisting of a total of two or more alternating layers of high melting point compound layers consisting of nitrides or carbonitrides of group 5a metals, and the average layer thickness of the metal layers arranged in contact with the cutting edge: 0.1 to 100 μm Through the bonding layer of WC
It is characterized by a composite cutting chip that has high bonding strength and is bonded to a base cemented carbide or cermet support. In addition, in the composite cutting chip of this invention, the average layer thickness of the bonding layer is limited to 0.1 to 100 μm because
If the thickness is less than 0.1 μm, the desired effect cannot be achieved in the above action, while if the thickness is 100 μm
If the thickness exceeds this, the rigidity of the chip itself decreases and it becomes more susceptible to plastic deformation, so the thickness was set at 0.1 to 100 μm. [Example] Next, the composite cutting chip of the present invention will be specifically explained with reference to an example. A supporting material having the composition shown in Table 1 and having dimensions of 10 mm in diameter and 2 mm in thickness is prepared, and the surface of the supporting material to be joined to the cutting edge is coated by a normal physical vapor deposition method. , a bonding layer having the composition and thickness also shown in Table 1 is formed, and in forming the bonding layer, the uppermost layer, that is, the layer in contact with the cutting blade, is arranged in alternating layers so that it is a metal layer. On the other hand, a green compact having the same composition shown in Table 1 as a cutting blade and having dimensions of diameter: 10 mmφ x thickness: 2 mm is prepared, and then the green compact for the cutting blade and the supporting material are prepared. The bonding layer is placed in a normal ultra-high pressure and high temperature generator and sintered under predetermined conditions within the range of temperature: 1200-1400℃ and pressure: 30-60kb. Invention composite cutting chips 1 to 13 were manufactured, respectively. For comparison purposes, conventional composite cutting chips 1 and 2 were manufactured under the same conditions except that no bonding layer was formed. Next, these composite cutting chips were cut into four parts by wire cutting, brazed to a WC-based cemented carbide base metal, and polished to produce a cutting tool with the shape of SNP432. Work material: high speed steel. (SKD−11, hardness: H _R
C60), cutting speed: 150m/min,

〔Effect of the invention〕

From the results shown in Table 1, although both the composite cutting chips 1 to 13 of the present invention and the conventional composite cutting chips 1 and 2 exhibit excellent wear resistance in continuous cutting of high-hardness steel, they show excellent wear resistance in interrupted cutting of high-hardness steel. Composite cutting chips 1 to 13 of the present invention all exhibit excellent cutting performance, whereas conventional composite cutting chips 1 and 2 all suffer from chipping on most of their cutting edges and reach the end of their service life in a short period of time. It was hot. As mentioned above, the composite cutting tip of the present invention
Not only continuous cutting of high-hardness steel, but also when used for interrupted cutting of high-hardness steel, there is no chipping of the cutting edge, and it exhibits excellent cutting performance over a long period of time, making it extremely reliable. It is something.

Claims (1)

[Claims] 1 A cutting blade made of a boron nitride-based ultra-high pressure sintered material is coated with a metal layer made of metals from groups 4a and 5a of the periodic table.
Consisting of two or more alternating layers of high melting point compound layers consisting of nitrides or carbonitrides of group 4a and 5a metals, and the average layer thickness of the metal layers arranged in contact with the cutting edge: 0.1 A composite cutting chip with high bonding strength that is bonded to a tungsten carbide-based cemented carbide or cermet support material through a ~100μm bonding layer.