JPH07328814A - Solid crystalline boron nitride radical ultra high pressure sintered material cutting tool superior in abrasion resistance - Google Patents

Abstract

PURPOSE:To provide a solid crystalline boron nitride radical ultra high pressure sintering material cutting tool exhibiting superior abrasion resistance in the case of high speed cutting. CONSTITUTION:A solid crystalline boron nitride radical ultra high pressure sintered material cutting tool includes Ti carbide/nitride 20-40% in vol.% consisting of one or two or more kinds out of Ti carbide, nitride, and carbide nitride, tungsten carbide 0.1-2%, aluminum nitride 1-5%, titanium boride 3-7%, and aluminum oxide 5-15%. And the rest consists of solid crystalline baron nitride radical ultra high pressure sintered material whose composition consists of solid crystalline boron nitride and unavoidable impurity and combined phase has such a structure as dispersedly distributing tungsten carbide, aluminum nitride, titanium boride, and aluminum oxide having grain sizes of 0.!X or less respectively on Ti carbide nitride base.

Description

Detailed Description of the Invention

[0001]

This invention relates to a cubic boron nitride (hereinafter referred to as CBN) based ultra high pressure sintered material which exhibits excellent wear resistance especially when used for high speed cutting of cast iron or steel. It relates to cutting tools.

[0002]

2. Description of the Related Art Conventionally, generally, for example, JP-A-59-27
As described in JP 303, it is composed of one kind or two or more kinds of carbides, nitrides, and carbonitrides of Ti (hereinafter, respectively represented by TiC, TiN, and TiCN) as a binder phase forming component. Ti charcoal / nitride: 20-4
A cutting tool composed of a CBN-based ultra-high pressure sintered material having a composition containing 0% and the remainder being CBN as a dispersed phase forming component and unavoidable impurities (above volume%, hereafter% indicates volume%). It is known and it is also known that it is used for cutting cast iron, steel and the like.

[0003]

On the other hand, in recent years, cutting machines have been remarkably improved in performance, and in combination with labor saving, the cutting speed has tended to be increased. However, the above-mentioned conventional CBN-based ultrahigh pressure sintered material cutting When a tool is used to perform high-speed cutting, wear progresses extremely rapidly, and the tool reaches its service life in a relatively short time.

[0004]

Therefore, the present inventors have
From the above viewpoints, the cutting tool made of the above-mentioned conventional CBN-based ultra-high pressure sintered material was paid attention to, and as a result of research aimed at improving wear resistance thereof, the cutting tool made of the above-mentioned conventional CBN-based ultra-high pressure sintered material was found. In the cutting tool, the binder phase of the CBN-based ultra-high pressure sintered material constituting the cutting tool is a tungsten carbide (hereinafter, denoted by WC) having a grain size of 0.5 μm or less on the base material of Ti carbon / nitride. Aluminum nitride (hereinafter, Al
N), titanium boride (hereinafter referred to as TiB ₂ ), and aluminum oxide (hereinafter referred to as Al ₂ O ₃ ), all of which are in a ratio of WC: 0.1
2%, AlN: 1~5%, TiB 2: 3~7%,
Al ₂ O ₃ : 5 to 15%, and a cutting tool composed of a CBN-based ultra-high pressure sintered material, which has a structure dispersedly distributed at a ratio of 5 to 15%. The research results show that it exhibits excellent wear resistance and exhibits excellent cutting performance over a long period of time.

The present invention has been made on the basis of the above-mentioned research results. In all of the following, as a binder phase forming component, TiC, TiN, and TiCN which consist of one or more kinds of TiCN. Nitride: 20-40%,
WC: 0.1-2%, AlN: 1-5%, TiB
₂ : 3 to 7%, Al ₂ O ₃ : 5 to 15%, and the rest has a composition of CBN as a dispersed phase forming component and unavoidable impurities, and the binder phase is Ti carbon / nitride. WC, Al whose grain size is 0.5 μm or less
Characterized by a cutting tool made of a CBN-based ultra-high pressure sintered material having excellent wear resistance, which is composed of a CBN-based ultra-high pressure sintered material having a structure in which N, TiB ₂ and Al ₂ O ₃ are dispersed and distributed Is.

Next, the reason why the component composition of the CBN-based ultra-high pressure sintering material constituting the cutting tool of the present invention is limited as described above will be explained. (A) Ti charcoal / nitride These components have the effect of improving strength and toughness, but if the content is less than 20%, the desired effect cannot be obtained for the above action, and as a result, cutting The blade is liable to be chipped or chipped (fine chipping), and when the content exceeds 40%, the wear resistance is sharply reduced. Therefore, the content is set to 20 to 40%. . Desirably, the content is 30 to 35%.

(B) WC, AlN, TiB ₂ and Al ₂ O ₃ As described above, these components are dispersed and distributed in the state of coexisting with the Ti carbon / nitride matrix to strengthen the binder phase, It has the effect of contributing to the improvement of wear resistance, and therefore any of these four components has a WC of less than 0.1%, Al
N: less than 1%, TiB ₂ : less than 3%, and Al
_{If the} content of ₂ O _{3 is} less than 5%, the desired effect of improving wear resistance cannot be obtained, and if any of these 4 components has WC:
2%, AlN: 5%, TiB ₂ : 7%, and Al ₂ O
Even if it exceeds ₃ : 15%, the wear resistance tends to decrease, so its content is WC: 0.1-2%,
_{AlN: 1~5%, TiB 2:} 3~7%, and Al ₂
O ₃ : It was set to 5 to 15%. Note that preferably WC:
0.5~1%, AlN: 2~4%, TiB 2: 4~6
%, And Al ₂ O ₃ : 7 to 12% is preferable. Further, if the particle size of these components exceeds 0.5 μm and becomes large, chipping starting from this tends to occur, so the particle size was defined as 0.5 μm or less.

[0008]

Example As a raw material powder, CBN powder having an average particle diameter in the range of 1 to 3.5 μm, and 0.5 to 1.8 μm
Prepare TiC powder, TiN powder, and TiCN powder having an average particle size in the range of m, and WC powder, AlN powder, TiB ₂ powder, and Al ₂ O ₃ powder, each of which has a particle size of 0.5 μm or less. These raw material powders were blended to the blending composition shown in Tables 1 and 2, and at the time of mixing, the raw material powders other than the CBN powder were first lined with WC-based cemented carbide with WC-based cemented carbide balls and an appropriate amount of acetone. Put in a container, load this container on a ball mill, crush and mix, then add CBN powder to this, wet mix for 72 hours on a rotary ball mill, and after drying, apply a diameter of 3 ton / cm ² : 20 mm x thickness: 1.
It is press-molded into a green compact having a size of 5 mm, and this green compact is pre-sintered in a vacuum of 3 × 10 ⁻⁴ torr at a predetermined temperature within the range of 1000 to 1300 ° C. for 30 minutes. Then, the WC-based cemented carbide base material having a diameter of 20 mm and a thickness of 2 mm is placed in an ultra-high pressure sintering apparatus in a state of being superposed, and the temperature is within a range of 1200 to 1400 ° C. at 5 GPa. Ultra high pressure sintering under conditions of holding at a predetermined temperature for 30 minutes, grinding the upper and lower surfaces, wire cutting into four, brazing to a WC-based cemented carbide base metal, and polishing to a predetermined throwaway tip shape Cutting tools made of the CBN-based ultra-high pressure sintered material of the present invention (hereinafter referred to as the present invention's cutting tools) 1 to 15 having a composition substantially the same as the composition by finishing, and comparative CB
Cutting tools (hereinafter referred to as comparative cutting tools) 1 to 8 made of N-based ultra-high pressure sintered material were manufactured.

In the comparative cutting tools 1 to 8, among the constituent components of the CBN-based ultra-high pressure sintered material constituting the comparative cutting tools, particularly, they are distributed and distributed in the base material made of Ti carbon / nitride to affect the wear resistance. WC, AlN, TiB ₂ or Al ₂
The O ₃ content (marked with * in Table 2) has a composition outside the scope of the present invention.

Then, with respect to the cutting tools 1 to 15 of the present invention and the comparative cutting tools 1 to 8 obtained as a result, a work material: a round bar of FCD70 (spheroidal graphite cast iron), a cutting speed: 400 m / min., A cut: 0.25 mm, feed: 0.2 mm / rev. , Time: 20 minutes, wet continuous high speed cutting test of cast iron, and work material: SCM415 carburized and hardened round bar, cutting speed: 300 m / min., Depth of cut: 0.1 mm, feed: 0.1 mm / Rev. For 20 minutes, a dry continuous high-speed cutting test of steel was performed, and the flank wear width of the cutting edge was measured in each test. The measurement results are shown in Tables 1 and 2.

[0011]

[Table 1]

[0012]

[Table 2]

[0013]

From the results shown in Tables 1 and 2, in the cutting tools 1 to 15 of the present invention, the CBN-based ultra-high pressure sintered materials constituting the cutting tools 1 to 15 have a thickness of 0.5 μm on the Ti carbon / nitride substrate. Fine WC, AlN, TiB ₂ and Al with the following grain sizes
_While having a structure in which ₂ O ₃ is dispersed and exhibiting excellent wear resistance in high-speed cutting, as seen in Comparative Cutting Tools 1 to 8, WC, AlN, TiB ₂ and Al ₂ O
It is clear that the inclusion of any of the above ₃ results in inferior wear resistance if the content is out of the range of the present invention.
As described above, the cutting tool made of the CBN-based ultra-high pressure sintered material of the present invention exhibits excellent wear resistance particularly in high-speed cutting as well as ordinary cutting, and exhibits excellent cutting performance for a long period of time. To do.

Claims (1)

[Claims] 1. A Ti carbon / nitride comprising 20% to 40% of a Ti carbide, a nitride, and a carbonitride of Ti as a binder phase forming component: 20 to 40%; 0.1 to 2%, aluminum nitride: 1 to 5%, titanium boride: 3 to 7%, aluminum oxide: 5 to 15%, and the remainder is cubic boron nitride as a dispersed phase forming component and unavoidable It has a composition of impurities (more than volume%),
A cubic boron nitride-based ultrahigh pressure having a structure in which the binder phase has a structure in which a tungsten carbide, an aluminum nitride, a titanium boride, and an aluminum oxide each having a grain size of 0.5 μm or less are dispersedly distributed on a base material of Ti carbon / nitride. A cubic boron nitride-based ultra-high pressure sintered material cutting tool with excellent wear resistance, characterized by being made of a sintered material.