JPS58113349A - Cubic system boron nitride-base material to be sintered under superhigh pressure for wear resistant cutting tool - Google Patents

Abstract

PURPOSE:To obtain a cubic system BN-base material to be sintered under superhigh pressure for a high hardness cutting tool with superior wear resistance, toughness, heat resistance and strength at high temp. by mixing cubic system BN with carbide, nitride or carbonitride of a specified metal and metals for a binding phase in a powdered state. CONSTITUTION:Powdered starting materials are mixed to prepare a material to be sintered for a cutting tool for cutting an Ni or Co superalloy or high hardness steel. The material to be sintered is composed of, by volume, 10-60% or 1 or >=2 kinds of components selected from carbides, nitrides and carbonitrides of Ti, Zr, Ta and W and solid solns. each consisting of >=2 kinds of these compounds, 1-10% Pd, 1-10% Ni and/or Co and 0.5-10% Al as binders for sintering or sintering accelerators and the balance 50-90% cubic system BN. A BN-base sintered cutting tool with high hardness is manufactured by sintering said material to be sintered with a superhigh pressure and high temp. generator.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a material that combines excellent toughness and wear resistance, as well as high hardness, and excellent heat resistance and high temperature strength. The present invention relates to a cubic boron nitride-based ultra-high pressure sintered material suitable for use in cutting tools for rigid materials such as superalloys and high-speed steel, as well as wear-resistant tools such as bearings and wire drawing dies. .

In recent years, cubic boron nitride-based ultra-high pressure sintered materials (hereinafter abbreviated as CBN-based sintered materials), which have extremely superior wear resistance compared to tungsten carbide-based sintered materials, have been used as cutting tools and wear-resistant tools. tend to be used.

CBN-based sintered materials can be roughly divided into two types depending on the binder phase of CBN particles forming the dispersed phase.
One is one in which the binder phase is composed of an iron group metal or a metal whose main components are an iron group metal and M, and the other is titanium nitride or titanium carbide.

The crystalline phase is composed of a ceramic compound containing aluminum nitride or aluminum oxide as a main component. However, in the former, as mentioned above, the binder phase is metal, so although it has high toughness, it is easily softened at high temperatures. Under these conditions, wear resistance and adhesion resistance will be insufficient, and sufficient cutting performance cannot be expected.
In other words, it can only be used under light load conditions. In addition, in the latter case, since the binder phase is composed of a ceramic compound as mentioned above, it has excellent wear resistance and welding resistance.
On the other hand, insufficient toughness cannot be avoided, and chipping and breakage are likely to occur under cutting conditions in which a large impact force is applied to the cutting edge, such as when milling high-speed steel.

Therefore, from the above-mentioned viewpoint, the present inventors conducted research to obtain a CBN-based sintered material that has both toughness and wear resistance.
i, Zr, Ta, and W carbides, nitrides,
and carbonitride, and one or more of these two or more solid solutions (hereinafter collectively referred to as metal carbon/nitride): 10 to 60%, Pd: 1 to 10%,
One or two of Ni and Co: 1 to 10
%, AA-0.5 to 10%, and the remainder consists of CBN and unavoidable impurities, and CBN accounts for 50 to 90% by volume, the resulting CBN-based sintered material has an excellent They found that it has both toughness and wear resistance, as well as excellent heat resistance and high-temperature strength.

This invention was made based on the above knowledge, and the reason why the component composition was limited as described above will be explained below.

(a) Metallic carbon/nitride These components are sintered under ultra-high pressure and high temperature,
It has a uniform effect of significantly improving the abrasion resistance and heat resistance of the material, but if the content is less than 100%, the desired abrasion resistance and heat resistance cannot be secured;
If the content exceeds 0%, the toughness of the material will decrease and, for example, when used for cutting, the cutting edge will likely be damaged, so the content was set at 10% to 60%.

Note that the content is preferably 20 to 40%.

(b) Pd In addition to promoting sintering, the Pd component also improves the toughness of the material.
Improves heat resistance (high temperature oxidation resistance) and welding resistance,
As a result, it has the effect of improving wear resistance, especially crater wear resistance, but if its content is less than 1%, the desired effect cannot be obtained; on the other hand, if it is contained in excess of 0%, the material The content was determined to be 1 to 10% because the wear resistance, especially the flank wear resistance, tends to deteriorate.

(c) Ni and Co Ni and Co components also have the effect of promoting sintering and improving the toughness of the material, but if their content is less than 1%, the desired toughness cannot be secured; If the content exceeds 10%, the heat resistance and welding resistance of the material will deteriorate, so the content was set at 1 to 10%.

(d) M The M component has a deoxidizing effect and a sintering promoting effect, as well as
When coexisting with Pa, Ni, and Co, it forms a Pd-(Ni, Co)-g alloy as a binder phase and has the effect of significantly improving the heat resistance of the material, but if the content is less than 0.5% However, if the content exceeds 10%, the wear resistance and toughness will decrease, so the content should be reduced to 0.5 to 1%.
It was set as 0%.

(θ) Volume ratio of CBN The CBN component has high hardness and excellent heat resistance. On the other hand, if the ratio exceeds 90 capacitance, the contact ratio between the CBN particles becomes too high, which not only causes the material to become brittle, but also reduces the sinterability, causing deteriorated areas and fine particles in the material. Since pores tend to remain and cause deterioration of wear resistance, the volume ratio was set at 50 to 90 volume ratio.

Next, the CBN-based sintered material of the present invention will be specifically explained using examples.

Examples of raw material powders include CBN powder with an average particle size of 6 μm, TiC powder and Ti powder with an average particle size of 1 μm.
N powder, T1CN powder, ZrC powder, ZrN powder, Zr
CN powder, TaC powder, TaN powder, TaCN powder, w
c powder, (Ti, W) C powder, and (Tmu Zr, Ta
) Metallic carbon/nitride powder consisting of CN powder, Pd powder, N1 powder, COC powder and M powder each having an average particle size of 0.5 μm as a binder phase forming component, and furthermore, an average particle size of 0.5 μm. Pd-M alloy (A1:
(containing 20%) powder and Ni-A1 alloy (AA:32
% containing) powder is prepared, and each of these raw material powders is
After blending with the composition shown in the table and mixing in a ball mill under normal conditions, the diameter:
Formed into a disk-shaped green compact having dimensions in the order of 25 balls φ x thickness = 1o, then these green compacts were inserted into a container of an ultra-high pressure and high temperature generator, and heated at a pressure crab of 50 tons/cIl at a temperature of: 1
By performing ultra-high pressure sintering at 200°C and holding time: 1 hour, high-pressure sintered materials 1 to 6 were produced with substantially the same composition as the compounded composition. Binder materials 1 to 6 each have a composition in which one of the constituent components (those marked with * in Table 1) is outside the scope of the present invention.

Next, the ultra-high pressure sintered materials 1 to 1 of the present invention obtained as a result
5 and comparative ultra-high pressure sintered materials 1 to 6, for the purpose of evaluating wear resistance, work material: Nimonik 80A, depth of cut: o, 3=m, feed: 0.1 mm/time, cutting speed;
For the purpose of conducting a cutting test under the conditions of 5 Qrn/min (hereinafter referred to as cutting test A) and evaluating toughness, the workpiece material was two-die steel (SKD-11, hardness: HRC60) l feed: 0. L dragon, depth of cut: 0.05° 0.1.0.15r
O, 2, 0, 25, 0, 3, and 0.4.

An intermittent cutting test (hereinafter referred to as cutting test B) was conducted under the conditions of cutting speed: 60 rIL, /min and no cutting oil, and cutting test A was performed until the flank wear of the cutting edge reached 0.2 dragon The cutting time was measured, and in cutting test B, the feed number where chipping was observed on the cutting edge was checked. These test results are shown in Table 1 along with the Vickers hardness.

From the results shown in Table 1, the ultra-high pressure sintered materials 1 to 1 of the present invention
No. 15 all have excellent cutting performance, but as seen in Comparative Ultra-High Pressure Sintered Materials No. 1 to No. 6, when the content of any of the constituent components deviates from the scope of the present invention. It is clear that the cutting performance deteriorates significantly.

As mentioned above, the CBN-based ultra-high pressure sintered material of the present invention is
It has excellent wear resistance and toughness, as well as high hardness, excellent heat resistance, and high temperature strength, so it can be used not only for cutting tools that require these properties, but also for bearings, wire drawing dies, etc. It exhibits excellent performance even when used as a wear-resistant tool.

Applicant: Mitsubishi Metals Corporation Agent Tomi 1) Kazuo

Claims (1)

[Claims] Carbides, nitrides, and carbonitrides of Ti, Zr, Ta, and W, and one or more solid solutions of two or more of these: 1O to 6o% r Pd
: 1 to 10%, one or two of Ni and CO: 1 to 10%, u: 0.5 to 10%, and the remainder is cubic boron nitride (contains 50 to 90 capacitance titanium). ) and unavoidable impurities (wt%), a cubic boron nitride-based ultra-high pressure sintered material for cutting and wear-resistant tools having both toughness and wear resistance.