JPS6240340A - Diamond-type sintered material for cutting tool - Google Patents

Abstract

PURPOSE:To obtain a diamond-type sintered material for cutting tools excellent in wear resistance and toughness by limiting a composition consisting of elements such as Ni, Co, Fe, Cr, etc., high pressure-phase BN with a proper grain size and diamond having specific grain size and structure. CONSTITUTION:The diamond-type sintered material has a composition consisting of, by volume, 2-10% of one or more elements among Ni, Co, Fe and Cr, 5-50% high pressure-phase BN and the balance diamond with inevitable impurities and further containing, if necessary, 0.2-5% Al, in which the average grain size of the high pressure-BN forming a dispersed phase is <=5mum, the diamond with 10-200mum grain size comprises >=50% of the grain-size distribution of diamond and the diamond forms a reticular skeleton structure. The above material has superior wear resistance and toughness, so that it can be suitably used as cutting cools in cutting a WC-base sintered hard alloy and the like.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention has excellent wear resistance and toughness, and is particularly applicable to tungsten carbide (hereinafter referred to as WC)-based cemented carbide and sintered high-speed steel. This relates to diamond-based □ sintered materials suitable for use as cutting tools for cutting hard alloys such as.

[Prior Art] Conventionally, as a cutting tool, (al) a diamond-based sintered material in which the binder phase forming component is mainly composed of an iron group metal or the like, and the remaining dispersed phase is composed of diamond.

(h) Similarly, it contains iron group metals, M, etc. as binder phase forming components, and the remaining dispersed phase is cubic boron nitride (hereinafter referred to as C
A CBN-based sintered material consisting of (denoted as BN).

(c) Boron or boride: o, oos ~o
,xsLM.

Contains diamond = 70 to 9595, and the rest is Fe and N as bonding phase forming components
i.

A diamond-based sintered material having a composition consisting of one or more of Co and Cr (the above % by volume, below % indicates 1% by volume).

The sintered materials listed above (al to (C)) are known.

[Problems to be Solved by the Invention] However, although the sintered materials fa) and (h) above have excellent toughness, they have poor abrasion resistance.
On the other hand, the above sintered materials (C) have excellent wear resistance but are inferior in toughness (l/l). The need for cutting hard alloys such as WCC cemented carbide sintered high-speed steel is increasing (: When used as a cutting tool, the above f
The sintered materials of al and (h) have severe wear, while the sintered materials of fc) above tend to chip the cutting edge.
Currently, all of them have a relatively short service life.

[Means to solve the problem]

Therefore, from the above-mentioned viewpoint, the present inventors have developed a sintered material that has excellent wear resistance and toughness and is suitable for use as a cutting tool for cutting hard metals that require these properties. As a result of conducting research to complete the development, we found that diamond powder with an average particle size of 10 μm or more and high-pressure phase boron nitride powder (with an average particle size of 5 μm or less) were used as raw material powders.
Boron nitride (=) has a crystal structure of cubic, wurtzite, and orthorhombic, and the high-pressure phase boron nitride referred to here refers to cubic and wurtzite, respectively, and hereinafter referred to as CBN. and WBN), and NL powder, Co powder, Fe powder, and Cr powder (hereinafter collectively referred to as (referred to as binder phase forming metal powder)
, these raw material powders are added to diamond powder, and one or more of the binder phase forming metal powders: 2 to 10
%, one or two of CBN powder and WBN powder:
M powder 20, 2-5LM prepared as raw material powder according to need.

These raw material powders are mixed under normal conditions,
When the green compact is nibble-molded and further ultra-high-pressure sintered, the average particle size of one or two of CBN and WBN that constitute the dispersed phase (hereinafter collectively referred to as high-pressure phase BN) is 5 μm. As described below, a diamond-based sintered material having a particle size distribution in which more than 50% of the diamonds have a particle size in the range of 10-100 μm, and in which the diamonds form a network-like skeleton structure is obtained, and the resulting diamond We obtained the knowledge that sintered materials have excellent wear resistance and toughness, and exhibit excellent cutting performance when used as cutting tools for cutting hard metals that require these properties. It is.

This invention was made based on the above-mentioned knowledge, and includes one or more binder phase forming metals: 2 to 10.
%, high pressure phase BN: 50% to 5, and if necessary, M: 0.2 to 5%, the remainder being diamond and unavoidable impurities, and a dispersed phase. The average grain size of the high phase pressure BN constituting the diamond is 5 μm or less, and more than 50% of the diamond is 1
It is a diamond-based sintered material for cutting tools that has a particle size distribution with a particle size in the range of 0 to 100 μm, and furthermore, diamond forms a network-like skeleton structure, and has excellent wear resistance and toughness. be. Next, the sintered material of the present invention (=) will be explained with the component composition and particle size distribution limited as described above.

Component composition (a) Metals forming the binder phase These components have the effect of improving sinterability by getting around between the diamond and high-pressure phase BN particles, as well as improving the toughness of the sintered material. If the content is less than 1%, the desired effect cannot be obtained; on the other hand, if the content is less than 1%,
If it exceeds 0%, the formation of skeleton structure becomes difficult and wear resistance deteriorates, so the content is set at 2 to 10%.

(h) High-pressure phase BN These components have high hardness and high heat resistance, and are finely dispersed in the matrix and have the effect of contributing to toughening and hardening of the sintered material. If the amount is less than 5%, the above-mentioned effect cannot be achieved sufficiently (2 Qfm), while if the content exceeds 50%, the diamond content is too small to achieve the desired excellent wear resistance. Since it becomes impossible to ensure the properties of the
%.

Note that CBN works effectively under cutting conditions where the cutting speed is fast, while WBN works effectively under cutting conditions where the cutting speed is slow but the depth of cut is large. You can use different WBNs, but
When these two components coexist, the cutting performance will be further improved under any cutting conditions.

(c) AJ This component combines with the binder phase-forming metal to form alloys and intermetallic compounds, thereby suppressing abnormal grain growth of diamond, as well as strengthening interparticle bonds and improving the toughness of the sintered material. However, if the content is less than 0.2%, the desired effect of improving the effect cannot be obtained, while if the content exceeds 5%, Since the abrasion resistance deteriorates, the content was determined to be 0.2 to 596.

■ Particle size distributionEven if the component composition satisfies the above conditions, if the average particle size of the high-pressure phase BN exceeds 5μmfr, the toughness will deteriorate. % or more is less than 10 μm in particle distribution, the interparticle bond between diamonds is low, and a solid phase forms a skeleton structure that is essential for improving wear resistance. If this happens, the toughness of the sintered material will deteriorate. Therefore, in order to ensure good wear resistance and hardness, the average particle size of the high-pressure phase BN is set to 10 μm or less. At least 50% of the diamonds have a particle size distribution (defined as 2) in which the particle size is within the range of 10 to 100 μm.

〔Example〕

Next, the sintered material of the present invention will be specifically explained in Example 2.

In addition, Ni powder, Fe powder, Cr powder, each having an average particle size of 1 μm, Co powder having an average particle size of 0.1 pm, and M powder having an average particle size of 1 μm were prepared as binder phase forming metal powders. , These raw material powders were blended into the composition shown in Table 1, and milled in a ball mill for 10 minutes.
After mixing for a period of time, the green compact (nibless molding) was performed at a pressure of 2 tons/-, and then this green compact was charged into a belt-type ultra-high pressure chamber, and WCC cemented carbide Co. +i
% content), temperature: 1600℃,
By performing ultra-high pressure sintering under the conditions of a pressure crab of 6.5 GPa and a holding time of 10 minutes, and cooling and removing the pressure, the sintered materials 1 to 18 of the present invention having substantially the same composition as the two compositions were obtained.
and conventional sintered materials 1 and 2 were manufactured, respectively.

Next, regarding the resulting sintered materials 1 to 18 of the present invention and conventional sintered material 1.2, the average grain size of the high-pressure phase BN and the diamond having a grain size within the range of 10 to 100 μm were determined. (Measure the double fold ratio, observe the structure, and then cut out the cutting tip by grinding and polishing.

Work material: WCC cemented carbide (Co: 20 weight, 1 hard% content),
Cutting speed: 15m/min.

Depth of cut: 0.5m.

Shipping: 0.1 van/rev.

Continuous cutting test under the following conditions: Cutting material: sintered high-speed steel (hardness: HRC70), cutting speed: 30 m/min.

Continuous cutting tests were conducted under the following conditions: depth of cut: 1, feed: 0.2 ru/rev, and in each test, the cutting time until the flank wear of the cutting edge reached 0.2 m was measured. . These results are shown in Table 1 (-).

〔Effect of the invention〕

From the results shown in Table 1, all of the sintered materials 1 to 18 of the present invention were significantly inferior to the conventional sintered materials 1.21 made of conventional CBN-based sintered materials and conventional diamond-based sintered materials. It is clear that it exhibits cutting performance and long cutting life.

As mentioned above, the sintered material of the present invention has excellent wear resistance and toughness, so it can be used for
When used as a cutting tool for cutting hard alloys such as CC cemented carbide sintered high speed steel, it exhibits excellent cutting performance over a long period of time.

Claims (2)

[Claims] (1) A composition containing one or more of Ni, Co, Fe, and Cr: 2 to 10%, high-pressure phase boron nitride: 5 to 50%, and the remainder consisting of diamond and inevitable impurities. (volume % or more), and the average particle size of the high-pressure phase boron nitride constituting the dispersed phase is 5 μm or less, and a particle size distribution in which at least 50% of the diamonds have a particle size within the range of 10 to 100 μm. A diamond-based sintered material for cutting tools with excellent wear resistance and toughness, which is characterized by the diamond forming a mesh-like skeleton structure. (2) Contains one or more of Ni, Co, Fe, and Cr: 2 to 10%, high pressure phase boron nitride: 5 to 50%, and further contains M: 0.2 to 5 %, with the remainder consisting of diamond and unavoidable impurities (volume %), and the average particle size of the high-pressure phase boron nitride constituting the dispersed phase is 5 μm or less, and 50% or more of diamond. 1. A diamond-based sintered material for a cutting tool having excellent wear resistance and toughness, characterized in that the diamond has a particle size distribution with a particle size in the range of 10 to 100 μm, and the diamond constitutes a mesh-like skeleton structure.