JPS60187659A - Cubic boron nitride-base ultrahigh-pressure sintered material for cutting tool - Google Patents

Abstract

PURPOSE:To develop a cubic boron nitride sintered material suitable for machining a hardly machineably material by mixing a hard compd. such as carbide of Ti and W in the form of powder with cubic boron nitride and pressurizing and molding the mixture with Ni, Co, etc. as a binder then sintering the molding in an ultrahigh-pressure high-temp. generator. CONSTITUTION:A mixed powder raw material having the compsn. consisting of 15-45% a hard material such as TiC, TiN, TiCN, WC and a solid soln. of (Ti, W)C, (Ti, W)CN, etc., 3-15% AlB2, 2-8% Pd, 5-10% Al2O3 or Al2O3 and AlN, 2-6% 1 or 2 kinds of Ni and Co as a binder and the balance cubic boron nitride is put in a green compact state into a metallic vessel. The material is heated to 800-1,200 deg.C and after the inside of the vessel is evacuated to a vauum and the vessel is sealed, the material is sintered under 40-70kb pressure and at 1,200-1,600 deg.C in an ultrahigh-pressure high-temp. device. The cutting tool material which has excellent wear resistance and toughness and permits machining of a difficult-to-machine material such as superalloy, high hardness steel is obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention has excellent wear resistance and toughness, and also has excellent welding resistance and thermal shock resistance.
Cubic boron nitride-based ultra-high pressure sintered material (hereinafter abbreviated as CBN-based sintered material) suitable for use as a cutting tool for cutting difficult-to-cut materials such as CBN-based or CO-based super alloys and high-hardness steel. It's something to do with.

[Conventional technology]

In recent years, there has been a tendency to use CBN-based sintered metals as cutting tools. This CBN-based sintering method is roughly divided into two types depending on the binder phase of cubic boron nitride (hereinafter not shown) particles forming the dispersed phase.

That is, one of them is one in which the binder phase is composed of an iron group metal or a metal mainly composed of an iron group metal and A1, and the other is one in which the binder phase is composed of an iron group metal or a metal mainly composed of an iron group metal and A1. The binder phase is composed of a ceramic compound containing as a main component.

(Problem that the invention attempts to solve) However, in the former case, as mentioned above, the binder phase is a metal, so although it has high toughness, it is easily softened at high temperatures, and therefore, it generates a large amount of heat. If used under severe cutting conditions, it will lack wear resistance and adhesion resistance and cannot be expected to exhibit satisfactory cutting performance, and can only be used under conditions with little heat generation. On the other hand, in the latter case, since the binder phase is composed of a ceramic compound as mentioned above, it has excellent 1'J wear resistance and welding resistance, but on the other hand, it lacks toughness. This is unavoidable, and there are problems such as pitting and chipping being likely to occur under cutting conditions in which large impact horns are applied to the cutting edge, such as when milling high-hardness steel such as die steel.

[Failure to solve the problem]

Therefore, from the above-mentioned viewpoints, the present inventors conducted research into a CBN-based sintered material that has superior wear resistance and toughness, as well as superior adhesive welding and thermal shock resistance. As a result, for each CBN-based sintered material, Ti carbide, nitride, and carbonitride, W carbide,
and a solid solution of two or more of these (hereinafter, each Ti
C, TiN, TiCN, WC.

(Ti,W)C, and (Ti,W)CN,
and one or more of the following (collectively referred to as "Ti and W carbon/nitride"): 15 to 45%.

Aluminum boride (hereinafter indicated by Δ!13×): 3 to 1
5%.

Pd: 2-8%.

Aluminum oxide (hereinafter referred to as Afiz(')3)
, or Affi20a and aluminum nitride (hereinafter referred to as 8IN): 5 to 10%.

One or two of Ni and Co: 2-6%.

The resulting CBN-based sintered material has excellent wear resistance, toughness, welding resistance, and thermal shock resistance. Therefore, they obtained the knowledge that it shows excellent cutting performance even when used as a cutting tool under conditions such as a cutting scoop that generates a large amount of heat, or a cutting condition where a large impact force is applied to the cutting edge.

This invention was developed based on the above findings, and the reason for limiting the component composition as described above will be explained below.

(a) Carbon/nitride of Ti and W These components have the effect of improving the wear resistance and welding resistance of the material, but if their content is less than 15%, the desired effect will not be achieved. On the other hand, if the content exceeds 45%, the toughness deteriorates, so the content was set at 15 to 45%.

(b) AffiBx During sintering, this component wraps around CBN particles and Ti and W carbon/nitride particles, and forms a strong bond with these rain particles, resulting in material strength and thermal shock resistance. However, if its content is less than 3%, the desired effect cannot be obtained; If the C content exceeds 15%, the material tends to become brittle, so the content was set at 3 to 15%.

(C) Pd This component has the effect of significantly improving the toughness of the material and further increasing the high temperature oxidation resistance and thermal shock resistance, but if its content is less than 2%, the above effects will not be achieved. The desired effect cannot be obtained, and if the content exceeds 8%, the hardness decreases and the wear resistance decreases, so the content was set at 2 to 8%.

(dJ Al 203 or △1203+Δff1NA
ffi203 has the effect of significantly improving the welding resistance of the material, and therefore exhibits excellent performance when used for extremely severe cutting that involves a large amount of heat generation. If the content is less than 5%, the desired effect of improving the above action cannot be obtained, and if the content exceeds 10%, the sinterability will deteriorate and microvoids will be more likely to occur in the material. Therefore, its content was determined to be 5 to 10%.

In addition, since the AIN component has the same effect as the Δt203 component, even if Affi203 is partially replaced with AffiN and co-contained, the same effect as when the Δ1zo3 component is contained alone can be obtained.

(e) Ni and G.

These components have the effect of further improving sinterability and further improving toughness when coexisting with PD, but
If the content is less than 2%, the desired effect of improving toughness cannot be obtained, while if the content exceeds 6%, the comfort of the material will decrease and the wear resistance will be impaired. The content was determined to be 2-6%.

It should be noted that the CBN-based sintered material of the present invention can be produced using the usual ultra-high pressure sintering method, that is, first, CBN powder, r
;c powder, TiN powder, TiCN powder, WC powder,
(Ti,W)C powder, (rl.

W) CN powder, △lBx powder, Pd powder, AEN powder,
Ae203 powder, N1 powder, Co powder, and N1-0
0 alloy powder is selected from these raw material powders, blended into a predetermined composition, mixed, and then subjected to WCC as required in the mixed powder state or green compact state.
Insert it into a metal container together with a cemented carbide plate, etc.
Heat this to a temperature of 800 to 1200"C and vacuum 11
2 gases are charged and sealed, and then this sealed container is attached to an ultra-high pressure and high temperature generator as described in, for example, Japanese Patent Publication No. 36-'234.63i, the pressure and temperature are increased, and the pressure and temperature are increased to 40. ~70Kb, thirst: 1200-1600
It can be produced by a basic process consisting of holding at a pressure J'3 and temperature in the range of 0.degree. C. for a few minutes to several tens of minutes, cooling and finally releasing the pressure.

In addition, when the CBN-based sintered material of the present invention is put to practical use as a cutting tool, it can be used alone or in combination with a high-rigidity material such as WCC cemented carbide remet.
It may be used as a way tip, or it may be used in a state in which these depths are removed by brazing the tip of a holder made of WC base, carbide alloy, or hardened steel.

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

Example original 1!1. CBN powder with an average particle size of 3 μm, TiC powder, TiN powder, TI C (35N o
, 5 powder.

WC powder, (Ti W )C powder, and 0.6 0.
4"' 0.6 WO, 4) CO, 7" 0.3 powder, and also Affi B2 powder with an average particle size of 0.7μ7+1 and Affi Bt 2 powder with an average particle size of 1μ? +1. Pd powder, Ni powder.

and Co powder, 1.5 μm AtN powder and Al
Prepare 2O3 powder, and add these raw material powders to the first
After blending with the composition shown in the table and mixing in a ball mill under normal conditions, the diameter: 13
mmφ×thickness: 1. The powder compacts were formed into disc-shaped compacts having dimensions of smm, and then these compacts were each made into a base material having a blending composition of 84% WC and 16% Co, and a diameter of: The part was stacked with a disk-shaped juice powder having dimensions of 13 mmφ x thickness: 3 mm, and was inserted into a container of a known ultra-high pressure and high temperature generator, and the pressure was 50 Kb and the degree of thirst was:
By ultra-high pressure sintering at 1500°C1 holding time: 5 minutes, the present invention CBN-based sintered materials 1 to 20 and comparative CBN with substantially the same composition as the blended composition were obtained.
I sintered materials 1 to 10 were produced, respectively. In addition, comparison C
For BN-based sintered materials 1311 to 10, is the content of any one of the constituent components (marked with * in Table 1) within the scope of this invention?

It has an unusual composition.

Then, the results are 1q and 1=Invention C[3N Base Sintered Materials 1 to 20 and Comparative CBN Sintered Materials 1 to 10, to evaluate the wear resistance] Objective C Vicker.

- Measure the steel hardness load: 5Kg>, and calculate the C fracture toughness value KC based on the length of the crack that occurred from the tip of the pressure 111 after Vickers hardness measurement, for the purpose of evaluating the ball toughness.
Furthermore, for the purpose of evaluating wear resistance, welding resistance +l, d3, and thermal shock resistance, workpiece material: die steel (SKD-11, hardness: HRC60), depth of cut: 0.2 mm, feed: 0.
1mm/rcv, Cutting speed: 60m/min
A cutting test was conducted without using cutting oil, and the cutting time until the flank wear of the cutting edge reached 0.1n1111 was measured. These results are shown in Table 1 as containing U.

〔Effect of the invention〕

From the results shown in Table 1, it can be seen that the CBN-based sintered mill of the present invention
~20 all have excellent wear resistance, toughness, and welding resistance 1
Comparative CBN-based sintered material 1 has J1 and thermal shock resistance, and therefore exhibits excellent cutting performance even when cutting difficult-to-cut materials that require these properties.
~10, when the content of any one of the constituent components falls outside the range of the present invention, at least one of the above properties becomes inferior, resulting in poor cutting performance. It is clear that it will become a thing.

As mentioned above, the CBN-based sintered tfA material of the present invention has excellent wear resistance and toughness, and is suitable for tough materials such as N1 base, CoJi super alloy, and high-hardness steel that require these properties. When used as a cutting tool for cutting materials, it exhibits extremely excellent cutting performance, and can also be used as a wear-resistant tool for bearings, wire drawing dies, etc. to maintain excellent performance for a long period of time. It has industrially useful properties such as being able to cover a wide range of areas.

Applicant: Mitsubishi Metals Corporation Agent Tomi 1) Kazuhito and 2 others

Claims (1)

[Claims] ■ Carbide, nitride, and carbonitride of i, carbide of W,
and one or more of these two or more solid solutions.
2 seconds or more = 15/45%. Aluminum boride: 3-15%. Pd: 2-8%. Aluminum oxide or aluminum oxide and aluminum nitride: 5-10%. 6% to one or two of Ni and Go. A cubic boron nitride-based ultra-high pressure sintered material for cutting tools, characterized by having a composition (more than %) containing cubic boron nitride and the remainder consisting of cubic boron nitride and unavoidable impurities.