JPS61179848A - High hardness sintered body for cutting - Google Patents

Abstract

PURPOSE:To develop high hardness sintered body superior in toughness and suitable for intermittent cutting of high hardness material to be cut and turning of cast iron system, by mixing BN of cubic or wurtzite structure and diamond at a specified ratio, and sintering them using a specified material as binder. CONSTITUTION:40-95vol% ultrahard material in which <=20% ratio of diamond is mixed with ultrahard crystal of cubic system BN or wurtzite structure BN, and the balance 5-60vol.% binder material of TiN - metal system or TiCN - metal system are mixed, compacted and said body is sintered at high temp. In this case, 50-80% in binder is composed of TiN or TiCN system, the balance 20-50% metal system contains one or 2 kinds selected respectively from the first group of Nb and Mo, the second group of Ni and Co, the third group of Al and Si, and one group is regulated to >=5% of the total quantity of three groups.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-hardness sintered body for cutting, which has a rectangular boron nitride crystal and/or a wurtzian boron nitride crystal, and a boron nitride crystal in which the - part is replaced with diamond. In particular, by improving the binding material, a sintered body with high toughness can be obtained, making it suitable for interrupted cutting of high-hardness work materials, turning of cast iron, etc.

Conventionally, this type of high-hardness sintered body for cutting has been bonded together with a normal bonding material, and examples of bonding materials include
Metal type materials made of a specific aluminum alloy as seen in Japanese Patent Laid-Open No. 53-77811 are known.

However, these sintered bodies do not necessarily provide satisfactory results in interrupted cutting or heavy cutting, and there is a demand for improvements in the bonding material.

The present invention was made in view of the above points, and consists of cubic and/or Wurtzian boron nitride and boron nitride partially substituted with diamond.
In a high-hardness sintered body for cutting that is sintered together with a metal-based, TiCN-based/metal-based binder under ultra-high pressure and high temperature, the boron nitride crystal has a volume of 40% including the amount of diamond replacement. The remaining binder is composed of TiN and/or TiCN alone or mainly composed of TiN and/or TiCN with ffa, Va, and 1FIa as the TiN-based and/or TiCN-based components. Those containing one or more of group metal carbides, nitrides and borides or AjL203 are selected, and the metal components include the first group of Nb and Mo, Ni and G.

A high-hardness sintered body for cutting with high toughness is composed of triple components selected from the second group of An and Si, and one or more of two or more selected from the third group of An and Si. It is.

An embodiment of the high-hardness sintered body for cutting of the present invention will be described below with reference to the drawings.

In FIG. 1, l indicates the high-hardness sintered body for cutting of the present invention. This high hardness sintered body l has a cubic crystal shape and/or
Alternatively, a Wurtz-shaped boron nitride crystal and a part thereof replaced with diamond are sintered together with a TiN-based metal-based or TtCN-based metal-based binder under ultra-high pressure and high temperature.

In this case, the ultra-high pressure and high temperature state is usually obtained by an ultra-high pressure generator such as a four-way pressurization type, a six-way pressurization type, a piston/cylinder type, or a belt type.

The high hardness sintered body l accounts for 4 by volume out of the total amount of the sintered body.
It contains 0 to 95%, and the rest becomes a binder. In this case, as a result of various studies, it was found that the amount of diamond substituted is preferably 20% or less relative to boron nitride. In addition, when cubic boron nitride and wurtz type boron nitride crystals coexist, about 100% of the wurtz type boron nitride mixed as a raw material is converted to cubic boron nitride by ultra-high pressure and high temperature sintering. In terms of cutting performance, it is preferable that the

As mentioned above, the binding material is composed of a TiN-based and/or TiCN-based component and a metal-based component,
TiN-based and/or 1tTiCN-based components are contained in the same amount or in the same amount as the metal-based components, and include TiN and/or TiCN alone or mainly composed of TiN and/or TiCN, in addition to ffa, Va, and Via group metals. carbide.

A material containing one or more of nitride, boride, or Al2O2 is selected. In this case, TiN and/or
Or those mainly composed of TiCN are TiN-based and/or
or at least 5 by volume of the total amount of TiCN-based components
It is necessary that the amount of carbon dioxide is 0% or more. This is because toughness is imparted to the high hardness sintered body l. Also,
Examples of carbides, nitrides and borides of IVa, Va and Vla group metals include carbides such as WC, Mo2C, Mo2
Nitride such as N, NbN, TiN, TiB2, ZrB2
Examples include borides such as.

Furthermore, as metal components, Nb and Mo (
1) 1st group, Ni and Co 2nd group, Al and Si
It consists of triple components, each of which has one or two components selected from the third group. In this case, it is necessary that E for one group be 5% or more of the total amount of the first to third groups.

This is to fully utilize the characteristics of the triple component.

The high-hardness sintered body 1 is then brazed into the cutout step 3 of a plate-shaped body 2 made of cemented carbide as shown in FIG. 2, for example, to participate in cutting. Further, in FIG. 3, a high hardness sintered body 1 is fixed on a base 4 made of cemented carbide by sintering under ultra-high pressure and high temperature. These sintering processes are explained in detail in the aforementioned Japanese Patent Publication No. 52-43846, etc., and can be easily carried out using an ultra-high pressure generator.

In addition, FIGS. 4 and 5 show modified examples,
A high-hardness sintered body 1 is provided in a central recess 5 of a disk-shaped base 4 made of cemented carbide. In this case, the cutting blade tip is constructed by cutting out an appropriate number of pieces as shown in FIG. 6, for example.

This was done because the high-hardness sintered body l has poor wettability with ordinary brazing metal, so the base 4 made of cemented carbide is positioned on the surface during brazing. It is.

Therefore, when constructing a cutting tool holder, the cutting tool holder is brazed with silver solder, copper solder, etc. within the cutout step 7 of the cutting tool shank 6, as shown in FIG. 7, for example.

Fig. 8 shows a cemented carbide plate-shaped body 2 that is brazed to the cutout step 3. In this case, since the central recess 5 is polygonal, the rear part is a straight line. It is designed to exhibit

(Example 1) In Example 1, a part of the cubic boron nitride crystal and the Wurtzian boron nitride crystal was replaced with diamond.
The composition, manufacturing conditions, Knoop hardness of the sintered body, etc. are shown in Table 1. The obtained high-hardness sintered body 1 was obtained by mixing the powder mixture in a ball mill for 30 hours, then drying it and molding it at a pressure of 4 t/cm2. It was sintered using an apparatus under the manufacturing conditions shown in Table 1.

In addition, in Experimental Examples 1 and 2.4 in Table 1, metallic Ni
and AfL are combined alone.

Even when mixed as an intermetallic compound found in N1AJL and N12Au3, the properties of the sintered body were similar to C. This means that C-oAJl, Co2A stand 5.

The same can be said of the intermetallic compounds found in Co4Au3 and Co2A.

Furthermore, as a result of cutting tests for Experimental Examples 1 to 5 in Table 1, it was found that the high-hardness sintered body for cutting of the present invention is capable of considerably high-speed cutting, even in hardened steel materials, and can be cut in 20 minutes. ~2
There was little flank wear during cutting for 5 minutes. In addition, apart from the cutting tests in Table 1, chilled cast iron (Shore hardness 62) and hardened 5KD-11 were tested.
Intermittent turning and milling were performed on the sample shown in Example 1, and it was confirmed that this method can also be used for these purposes. In this case, for interrupted cutting of chilled cast iron, two notches (10 mm wide) are provided in the axial direction of the workpiece with a diameter of 5011 mm, and the cutting conditions are cutting speed V = 8.
0s/sin, depth of cut d=0, 2ms, feed f
= 0, 15m/rev is also noted. and,
The flank wear was 0.28m with cutting time of 45 minutes.
No chipping was observed on the cutting edge.

Further, milling of the 5KD-11 was carried out using a single blade attached to a cutter body (not shown). The cutting conditions at this time are cutting speed V = 200
x/win, depth of cut d=0.5cm, feed f=0.1
■■/The blade broke in the cutting area of 3000c shoe 2.

On the other hand, with the conventional product for comparison, the cutting edge was chipped during interrupted turning, and during milling, the cutting area was about the size of a hand. The reason for this superiority and inferiority is considered to be that the high-hardness sintered body 1 for cutting of the present invention has improved high-temperature characteristics, toughness, etc. through the selection of the binder.

(Example 2) In Example 2, diamond is included in the boron nitride crystals of the Kekabana type and Wurtz type.

As a result, it was found that the product of the present invention was superior to the comparative amounts. It was particularly effective for cast iron work materials.

Margin below (Example 3) In Example 3, cubic boron nitride and Wurtzian boron nitride were made to contain diamond,
For the binder, T i N.

This is T i CN containing other additives. So, what about other additives?

rVa, Va, carbides, nitrides, borides or Al2O3 of group VIa metals are meant.

As a result, the products of the present invention all showed superior results compared to the comparative products.

In addition, in contrast to Example 1 and Example 2, Example 3 has the following:
The damage to the cutting edge was clean, there was no chipping, and the occurrence of notch wear tended to be low.

Blank space below (Example 4) Example 4 shows that for cubic crystal type and Wolf type boron nitride,
A part of it is replaced with diamond, making it a champion mixed crystal. Also regarding binding materials.

It contains other additives in addition to T i N and T i CN. Also in this case, Example 3
Similarly, other additives mean carbides, nitrides, borides, or A203 of group metals such as a, Va, and Via.

As a result, the products of the present invention all showed superior results compared to the comparative amounts.

In addition, Example 4 showed the same tendency as Example 3 described above, but particularly showed effective results in turning low carbon steel.

The following margins The high-hardness sintered body l for cutting of the present invention is the example 1 described above.
~4 and various experiments, the following items were confirmed.

(1) Cubic and/or Wurtzian boron nitride and diamond crystals can be contained in a range of 40 to 95% per volume.

The range is selected depending on the cutting conditions and the material to be cut.

In addition, when cubic and wurtz-type boron nitride are mixed crystals, about half of the wurtz-type boron nitride blended as a raw material is converted to cubic boron nitride crystals by sintering under ultra-high pressure and high temperature. This is due to the trend of cutting test results. Furthermore, the amount of diamond replacement is preferably 20% or less (not including 0); if the amount of diamond replacement exceeds 20%, heat generation during cutting will cause diamond deterioration in the case of iron-based work materials. This is because it becomes extremely inconvenient.

■ TiN-based and/or TiCN-based components are Ti
N and TiCN are each used alone or mainly composed of TiN and/or TiCN, and IVa, Va, and V
One or two carbides, nitrides, and borides of group Ia metals
Applicable to those containing seeds or more.

The TiN-based and U/TiCN-based materials are used because these systems form a solid solution, lowering the sintering temperature under high temperature and high pressure, and facilitating sintering. This is also because toughness is also improved.

If TiN and/or TiCN are the main components,
It is preferable that TiN and TiCN occupy at least 50% or more by volume. Also, the upper limit is 80%
is suitable.

(2) The TiN-based and/or TiCN-based components should be contained in an amount equal to or greater than the metal-based components, that is, 50 to 80% of the binder.

This is because the high temperature properties characteristic of TiN and/or TiCN systems are required to work effectively.

■ The metal component as a binder is a triple component in which one or two components are selected from the first group of Nb and Mo, the second group of Ni and Co, and the third group of AM and Si. and as a group, the first
Contains 5% or more of the total amount from Group 3 to Group 3.

These may be combined as single metal powders, alloy powders, or intermetallic compounds. In this case, the components of the third group promote the solid solution formation of the components of the first and second groups, and the presence of the third group serves to increase the high-temperature strength.

These components include the T i N system, TiCN
It acts as a bonding agent for the components of the system, resulting in a strong bond.

As explained above, the present invention provides a TiN-metallic and/or TiCN-metallic bond which has been identified to improve high-temperature properties, toughness, etc. for high-hardness sintered bodies for cutting. Since the material is selected, it is particularly suitable for interrupted cutting of high-hardness work materials and turning of cast iron.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing one embodiment of the high-hardness sintered body for cutting of the present invention, Fig. 2 is a perspective view of the case where it is brazed to a cemented carbide plate, and Fig. 3 is a perspective view showing an embodiment of the high-hardness sintered body for cutting of the present invention. Figure 4 is a perspective view of the product being sintered and fixed on a base made of hard metal under ultra-high pressure and high temperature.
A front view showing a modification of the figure, FIG. 5 is v-v in FIG.
FIG. 6 is a perspective view of the cutting edge cut from those of FIGS. 4 and 6; FIG. 7 is a perspective view showing a state in which the cutting edge tip is brazed to a cutting tool holder, and FIG. 8 is a perspective view showing a state in which a deformed cutting edge tip is brazed to a cemented carbide plate. l... High hardness sintered body for cutting 2... Plate-shaped body 4... Base 5... Central recessed part 6... Bit shank

Claims (2)

[Claims] (1) Contains 40 to 95 volume % (hereinafter referred to as %) of cubic and/or Wurtzian boron nitride crystals and diamond, with the remainder being TiN-metallic and/or TiC
In the high-hardness sintered body for cutting, which is made of an N-based metal-based bonding material, the diamond content is 20% or less (excluding 10%) of the boron nitride crystal, and the diamond content is 20% or less (excluding 10%) of the boron nitride crystal. The TiCN-based component is such that TiN and/or TiCN accounts for 50 to 80% of the binding material and does not contain any other additives; 50-20% of the material
within the range of the first group of Nb and Mo, Ni and Co
The second group contains one or more selected from the third group Al and Si, and each group contains 5% or more of the total amount of the first to third groups. A high-hardness sintered body for cutting. (2) Contains 40 to 95 volume % (hereinafter referred to as %) of cubic and/or Wurtzian boron nitride crystals and diamond, with the remainder being TiN-metallic and/or TiC
In the high-hardness sintered body for cutting, which is made of an N-based metal-based binding material, the diamond content is 20% or less (excluding 0%) of the boron nitride crystal, and the TiN-based and/or TiCN-based components in the binder.
within the range of 0% and TiN and/or TiCN
is 50-80% in this system, with the rest being IVa, Va, and V
It is made of one or more of carbides, nitrides, and borides of group Ia metals, or Al_2O_3, and furthermore, the metal component accounts for 50 to 20% of the binder.
within the range of the first group of Nb and Mo, Ni and Co
The second group contains one or more selected from the third group Al and Si, and each group contains 5% or more of the total amount of the first to third groups. A high-hardness sintered body for cutting.