JP2626006B2 - Cutting tips made of cubic boron nitride-based ultra-high pressure sintered material capable of cutting difficult-to-cut materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention particularly relates to Ni-based superalloys, Co-based
Cu-based boron nitride-based ultra-high pressure that demonstrates excellent performance when used for cutting difficult-to-cut materials such as Ni-base heat-resistant alloys and WC-base cemented carbide (Rockwell hardness A scale 80-85) The present invention relates to a cutting tip made of a sintered material (hereinafter, referred to as a CBN-based sintered material).

[Conventional technology]

Conventionally, carbides, nitrides, and borides of titanium, tungsten carbide, oxides and nitrides of Al (hereinafter referred to as TiC, TiN, TiB ₂ , WC, Al ₂ O ₃ , and AlN), and one or more of these two or more solid solutions: 20 to 60%, with the balance being A cutting insert composed of a CBN-based sintered material having a composition (above volume%, below% shows volume%) consisting of cubic boron nitride (hereinafter, shown as CBN) and unavoidable impurities must be used Is well known.

[Problems to be solved by the invention]

However, the above-mentioned conventional CBN-based sintered material cutting tip,
At present, when used for cutting difficult-to-cut materials as described above, the cutting edge is chipped or chipped due to insufficient chipping resistance, and cannot be put to practical use.

[Means for solving the problem]

In view of the above, the present inventors have focused on the above-mentioned conventional CBN-based sintered material cutting tip, and have conducted research to impart chipping resistance thereto. CBN as a phase-forming component is composed of particles having an average particle diameter of 10 μm or less, and 50% or more of the CBN particles have an average particle diameter of 10 μm or less. Up to 8 long CBN
When CBN is oriented perpendicular to the rake face (upper face) of the cutting edge and oriented parallel to the flank face (side face),
It has been found that the fracture resistance is remarkably improved, and excellent cutting performance is exhibited even when used for cutting difficult-to-cut materials.

The present invention was made based on the above findings, the binder phase forming _{component, TiC, TiN, TiB 2,} WC, Al 2 O 3, and AlN, as well as of those of two or more solid solutions One or more kinds: 20 to 60%, and the remainder is composed of a CBN-based sintered material having a composition comprising CBN as a disperse phase forming component and unavoidable impurities. 50% or more of the CBN as a component is composed of a long CBN having an average particle diameter of 10 μm or less, preferably a long CBN having a ratio of a major axis to a minor axis of 1.5 to 8; CBN is oriented perpendicular to the rake face of the cutting edge, and is oriented in a direction parallel to the flank.It is characterized by a cutting tip made of CBN-based sintered material that can cut difficult-to-cut materials. is there.

In addition, if the proportion is less than 50%, the long CBN in the CBN-based sintered material constituting the cutting tip of the present invention does not contribute to the desired improvement in toughness, and the rapid improvement in toughness starts at 50%. Therefore, the ratio was set at 50% or more.

In addition, even if the average particle size of the long CBN exceeds 10 μm, a decrease in toughness is observed.
μm or less.

Further, with respect to the content of the binder phase forming component constituting the CBN-based sintered material, if the content is less than 20%, the CBN becomes relatively large and the predetermined strength cannot be secured. If the content exceeds 60%, the proportion of CBN becomes too small and the wear resistance is remarkably reduced. Therefore, the content is set to 20 to 60%.

〔Example〕

Next, the cutting tip made of the CBN-based sintered material of the present invention will be specifically described with reference to examples.

As raw material powders, various types of powder for forming a bonding phase shown in Table 1 each having an average particle size of 1 to 3 μm, and granular CBN powder having an average particle size of 3 μm; Prepare a long CBN powder that has a particle size and is adjusted to have a length ratio of 1.5 or more by sieving at a length ratio of 1.5 (long axis to short axis ratio). ,
Each of these raw material powders was blended into the blending composition shown in Table 1, acetone was added thereto, and the mixture was wet-mixed for 72 hours using a WC-based cemented carbide ball mill and dried. For the purpose of unidirectional orientation, 3
Extruded at a pressure of n / cm ² to make a rod with a diameter of 10 mm,
In this way, the rod-shaped green compact in which the elongated CBN is blended along the length direction is sliced into a tablet shape with a thickness of 2.5 mm,
Then, it is superimposed on a WC-based cemented carbide base metal having a diameter of 10 mm and a thickness of 2.5 mm (Co: 10% by weight).
Ultra-high pressure sintering under the conditions of 50,000 atm, temperature: 1300 ° C, and holding time: 1 hour, sintering, then dividing into four, and grinding to obtain the CBN of the present invention having substantially the same composition as the compound Cutting tips made of a base sintered material (hereinafter referred to as cutting tips of the present invention) 1 to 8 and cutting tips made of a comparative CBN base sintered material (hereinafter referred to as comparative cutting tips) 1 to 3 were produced, respectively.

The same conditions were used except that the above-mentioned powder for bonding phase formation and granular CBN powder were used as raw material powders, and the mixed powder after drying was press-molded at a pressure of ² ton / cm ² to obtain a tablet-like green compact. Thus, cutting tips 1 to 4 made of conventional CBN-based sintered material (hereinafter referred to as conventional cutting tips) were manufactured.

Note that the comparative cutting tips 1 to 3 are CBN
The component composition of the base sintered material and the proportion of long CBN are out of the scope of the present invention. In addition, in the conventional cutting tips 1 to 4, all of the CBN constituting the cutting tips 1 to 4 have a granular shape.

Then, for the various cutting inserts obtained as a result, work material: Inconel 718 (Ni-based alloy), cutting speed: 200 m / min, feed: 0.3 mm / rev., Cutting depth: 0.7 mm, cutting oil: water soluble , Continuous cutting test under the following conditions, Work material: WC based cemented carbide (Co: 20% by weight), Cutting speed: 25m / min, Feed: 0.1mm / rev., Depth of cut: 1mm An intermittent cutting test was performed, and in each of the tests, chipping and chipping of the cutting edge occurred, and the cutting time until the service life was measured. The results are shown in Table 1.

〔The invention's effect〕

From the results shown in Table 1, the cutting tips of the present invention 1 to 8
Shows excellent cutting performance for cutting difficult-to-cut materials that cannot be applied with conventional cutting inserts 1 to 4, whereas CBN-based sintered material is bonded as shown in comparative cutting inserts 1 to 3. When the proportion of the phase-forming component or the elongated CBN is out of the range of the present invention, it is apparent that a predetermined excellent wear resistance or fracture resistance cannot be obtained.

As described above, the cutting tip made of the CBN-based sintered material of the present invention has remarkably excellent fracture resistance as compared with the conventional cutting tip made of the CBN-based sintered material, and is difficult to apply conventionally. It enables cutting of cutting materials and exhibits excellent cutting performance.

Claims (1)

(57) [Claims] 1. A binder phase forming component comprising one or more of Ti carbides, nitrides and borides, tungsten carbide, Al oxides and nitrides, and two or more solid solutions thereof. : 20 to 60% by volume, and the remainder is composed of a cubic boron nitride-based ultra-high pressure sintered material having a composition of cubic boron nitride as a disperse phase forming component and unavoidable impurities. The cubic boron nitride as a disperse phase forming component comprises at least 50% by volume of a long cubic boron nitride having an average particle size of 10 μm or less; Cubic boron nitride capable of cutting difficult-to-cut materials, characterized in that the surface is oriented in a direction perpendicular to the rake face (upper face) of the cutting blade and in a direction parallel to the flank face (side face). Cutting tip made of base ultra-high pressure sintered material.