JPS5864342A - High hardness sintered body for tool and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a high hardness sintered body for a tool with superior wear resistance and high toughness by sintering a mixture consisting of high pressure phase type boron nitride, an iron group metal, Al and Cu in a prescribed ratio at a prescribed temp. under a prescribed pressure. CONSTITUTION:Powder of high pressure phase type boron nitride which is cubic system boron nitride is mixed with powder of >=1 kind of iron group metal or powder of a compound of the metal, Al powder and Cu powder. This mixture is die-pressed and sintered at >=900 deg.C under >=20 kb pressure to obtain a sintered body composed of 75-95vol% high pressure phase type boron nitride and the balance alloy consisting of 25-90wt% iron group metal, 5-50wt% Al and 5-45% Cu.

Description

[Detailed description of the invention] Cubic boron nitride (C!ubic Boron N1t)
ride (hereinafter abbreviated as chill) is a material with the second highest hardness after diamond, and is synthesized under ultra-high pressure and high temperature. Sintered bodies bonded with CBN f Co or the like are currently used in some cutting applications. When this CBN sintered body is used as a cutting tool, especially when there is interrupted cutting,
The drawback was that the cutting edge of the tool would break off in the early stages. The present invention overcomes these drawbacks and relates to a new OBN sintered body that has high toughness and excellent wear resistance.

As mentioned above, OBN has high hardness, excellent heat resistance and abrasion resistance, and is a useful material. Various attempts have been made to sinter only this OBN.
As described in the No. 9411 publication, it is necessary to sinter at an ultra-high pressure and high temperature of about 70 Kk or more and 1?00 Kk or more. Current ultra-high-pressure, high-temperature equipment can generate such high-pressure and high-temperature conditions, but if the installation is scaled up to an industrial scale, the number of service cycles of the high-pressure and high-temperature generation part will be limited, making it impractical to use OBM. Although the sintered body of chisel has high hardness,
Poor toughness when used as a tool. For this purpose OBM
It is conceivable to improve these drawbacks by adding a suitable binder to the material.

One of the well-known methods is a method using a metal bonding material, an example of which is a sintered body bonded with commercially available OBM i metal co.

The sintered body used as the Cof binder has low toughness as described above. In order to determine the cause of this, the composition of the OBN sintered body of the CO binder was investigated using the I line.

A large amount of polide was detected, but no metal CO was observed, indicating that the binder of this OBM sintered body was CO polide. Normally, these voids are highly hard but extremely brittle substances, and it was estimated that the toughness of the sintered body of such a light void binder would be low. The present inventors thought that in order to increase the toughness of the 0Bli sintered body, it would be good to suppress the generation of polide so that it would not be the only binder, and conducted various studies.90 As a result, the binder It has been found that the addition of Ouf to the material suppresses the generation of polide. For example, when only iron group metals are used as cement in a sintered body, even if the kv of iron group 4JiJ4 increases, a liquid phase occurs during sintering [7, and most of it becomes polide. Put it away. However, if the iron group metal contains a certain amount of M, even if a liquid phase occurs during sintering, the generation of polide is suppressed, and the solid solution alloy of the iron group metal and O becomes a solid solution. It was found that it remained in the sintered body. Utilizing this current &C, non-inventors etc. have developed 0BI(
In order to produce sintered IC1, research gold car neta0 result, CBN
It was found that an FC sintered body bonded with an alloy of T-iron group, M, Cu, and At has unprecedentedly high toughness and 4 wear resistance.

It is estimated that the sintered body of this invention will exhibit excellent performance in the next p days. It is thought that the iron group metal and O are bonded through an alloy of Mut, but OBN-polide-iron group metal and O,
This is thought to be due to the fact that the bonding strength between Mut alloys is very high, the polide phase is thinly rounded, and cracks rarely occur in the polide circles, and alloys of iron group metals, Cu, and Mut have high toughness. It will be done. Further, the performance of the sintered body of the present invention is improved by adding Muttm.

This is, for example, liquid phase sintering of WO-Co cemented carbide.
If the hard particles are dissolved in the binder phase and the re-precipitation phenomenon occurs, a highly bonded bond between the binder phase and the hard particles or between the hard particles can be obtained. This is because a phenomenon similar to this occurred due to the presence of a proboscis that combines the mucous membranes. Furthermore, another factor is that the silica reacts with a part of the OBM to produce highly hard silicas Bfi and tMt, which are firmly bonded to the binder.

The binding material in the sintered body of the present invention is especially effective when the OBN content is large. When the feces content of CBN is high, the binder is relatively reduced and the binder is not mixed uniformly by itself. IIK permeates around the periphery of the steel, forming a dense sintered body, suppressing the generation of polide, and preventing the formation of a binder phase consisting only of polide, so that the toughness does not deteriorate.

In the sintered body of the present invention, the content of OBM is 75q1 by volume.
1 or more and 95 or less is better oCBN content is 75 by volume
If it is less than 1, the amount of binder increases relatively and there is a problem in wear resistance. Further, 1. If the content of OBN exceeds 95- by volume, the amount of binder decreases and the toughness decreases. (3u
The content is preferably from 5 to 4S by weight in the binder. If the content of O is less than 5s, the formation of polide cannot be suppressed, and if it exceeds 45s, the strength of the binder will decrease. The content of iron group metals is 25% by weight in the binder.
96 or more and 90- or less is preferable. If the content of iron group metal is less than 25%, the strength of the binder will decrease, and if it exceeds 90%, the amount of cutV in the binder will be relatively reduced and the content of polide O will decrease.
The effect of containing Omu, which cannot suppress the form FILt, appears when the content of Mut in the binder is 5 or more by weight. In addition, if the content of Mut exceeds 50% by weight in the binder, the strength of the binder decreases, which is undesirable, and the optimum alloy content is 5 to 50%.◎ Iron group metals, CU, Mu Various methods can be considered for adding 1t. For example, if metal powder is added to OBM powder before sintering,
The simplest method is to add the compound in the form of powder. In addition, during sintering with iron group metals, it is also possible to melt and infiltrate the sintered body from the outside.In manufacturing the sintered body, ultra-high pressure and high temperature equipment used for diamond synthesis is used to create a sintered body under pressure of 20xb or higher. ,temperature?
Particularly preferred sintering pressure and temperature conditions are pressure 50 Kb ~ 70 Kb, temperature 1100°C ~ 1
The temperature is 500°C. The upper limits of these pressure and temperature conditions are all within the range of practical operating conditions for ultra-high pressure and high temperature equipment on an industrial scale. Furthermore, the pressure and temperature conditions are within the stability range of high-pressure phase type boron nitride shown in Figure 1. When using such an excellent sintered body as a cutting tool, it is best to use the high hardness sintered body only in the part that will become the cutting edge.

It has excellent toughness and thermal conductivity, and can fully demonstrate its performance when used in conjunction with 9 cemented carbide.

However, if it is directly bonded to cemented carbide, the bonding strength will be weak and it may not be possible to use it for interrupted cutting if the OBM content is high. 0 To obtain sufficient bonding strength, C! BN'
Contains less than 70 parts by volume, with the remainder being Ti, Zr,
If 1N% of carbides, nitrides, and carbonaceous compounds are used for bonding, an intermediate layer consisting of a mixture of these or a mutual solid compound may be used for bonding.

Further, similar studies were conducted on wurtzite boron nitride, which is another form of high-pressure phase boron nitride, and results similar to those obtained when OBN was used were obtained.

[Example 1] A mixed powder containing OBN particles with an average particle size of 5 μm by volume of 80% [7], the remainder being a binder powder was prepared. The binder powder is a mixture of Mu powder, Ou powder, and Ml powder in weight ratios of 20, 20, and 60, respectively, which is heated in a vacuum furnace at 1000°C for 50 minutes, and then pulverized.
Using. This mixed powder of 081 particles and binder powder was placed in a container made of MQ with an outer diameter of 14a*inner diameter of 10mm.
Fill the ridge A4F with cemented carbide of the composition (outer diameter 10 cm, height 2-5 m). Furthermore, a cemented carbide (outside: 9110 mm, height: 2 mm) was placed on top of the diamond, an MO O plug was placed on the container, and the entire container was placed in an ultra-high pressure apparatus used for diamond synthesis. Pressure: 150 Km) and then 1500°C
◎The good sintered body was taken out and ground using a diamond grindstone until a high hardness sintered body appeared, and further heated to -1iF using diamond paste.
T polish. Observation with an optical microscope revealed that the sintered body had good pores.As a result of examining the product of the sintered body with a density of 1 and 6◎ξ by kXm diffraction, it was OBM, MujM.

In addition to the 0u-111 alloy, trace amounts of MutBs and
of polide could be detected. For comparison, a sintered body with the above composition excluding O was also produced under the same conditions and examined by X-1 folding.

As a result, OBM, MutN, Mul-Bm and a large amount of N
1 was observed to be ridden, and 9 metal M1 was not detected. These two types of sintered bodies and the commercially available volume are 90
A 8KD11 die steel (H, o
61) k, Cutting speed 100m/Im1 Depth of cut 05-1 Feed a5/r・Ma Dry test 9.

As a result, the sintered body of the present invention containing Cu t- could be cut for 20 minutes until the cutting edge was damaged, whereas the sintered body containing Cu t-
The cutting edge of both the f-free sintered body and the commercially available sintered body broke after 6 minutes of cutting.Example 2 The binder powder shown in Table 1 was prepared. The binder powders having these compositions were heat treated and pulverized in the same manner as in Example 1.

This binder powder was mixed with 0Bli powder having an average particle size of 5s to prepare a mixed powder having the composition shown in Table 2.

It is not a sintered body of the present invention.

In the same manner as in Example 1, a container made of KWO-4 COS hard alloy was placed, a cemented carbide was placed on top of it, a stopper made of O was put on, and a 50 g K Apply pressure L, then heat to IJOOC, hold for 20 minutes, and then cut these sintered bodies and attach a lock to one corner of a cemented carbide indexable tip. Create nine. For rounding to evaluate cutting performance, first perform interrupted cutting with a single blade using a face milling machine. The workpiece material is heat-treated BED 11 die steel with an outside diameter of 9 IQ OmoHBo62 ◎ Cutting speed 111200 shoulder/min, depth of cut 1
5■ Stitching, 5@ cutting with feed speed 9 speed tan y■/blade, then 5 same with A12 blade/blade, then 5 same with A1-4 toughness, and then increase the tough conditions and bake. The defect shape m of the body was examined. For comparison, a commercially available volumetric steamed rice cake has an OBI f of approximately 90-
A chip of a sintered body containing % oQ as the main component and bonded with a friendly metal was also prepared and tested.The results are shown in Table 2. Also, outside 41100xg DIKD 11 f cutting speed 100 m/'s + w depth of cut α2■, feed IIL1■
/rev Dry cutting is performed and the machining time until the tool flank wear reaches α2 snow is also shown in Table 2.

[Example 3] Using wurtzite type boron nitride powder synthesized by the impact technique with a particle size of 1 μ or less, the binder powder used in Example 2 and 90 wurtzite type nitride fs raw powders were combined. The powder was mixed in a proportion of 10 volumes.

This powder was filled into an MO container with the same configuration as in Example 1, and then sintered using an ultra-high pressure and high temperature apparatus. The hardness FIK#'i Vickers hardness of the sintered body was 3900.

[Brief explanation of the drawing]

Figure 1 is for explaining the manufacturing conditions of the sintered body of the present invention, and shows the thermodynamic stability region on the pressure-temperature phase diagram of high-pressure phase boron nitride. ) Akira Agent Ryo Hagiwara Ichitenji C) January 7, 1980 Commissioner of the Patent Office Haruki Shimada 1 Indication of the case 1983 Patent Application No. 162781 2 Name of the invention High hardness sintered body for tools and its manufacturing method 3. Address related to the amendment case: 5-15 Kitahama, Higashi-ku, Osaka Name ('
213) Sumitomo Electric Industries, Ltd. (Name) Representative: Masao Kamei 4, Agent: 5 Date of amendment order: Voluntary amendment: 6, Invention thicket increased by amendment None. Z Target of amendment (1) ``Claims'' section a of the specification Contents of amendment (1) The entire scope of claims on pages 1 to 2 of the specification shall be amended as shown in the appendix. Claims (1) Contains high-pressure phase boron nitride from 75 to 95 by volume, the remainder being an alloy of iron group metals, kl, and Cu, the content of iron group metals in the remainder being 25% or more by weight9
0% or less, the At content is 5 or more and 50 or less by weight, and the Cu content is 5 or more and 45 or less by weight.
A high-hardness sintered body for tools, characterized in that the hardness is less than or equal to 1. (2) The high-hardness sintered body for tools according to claim (1), wherein the high-pressure phase type boron nitride is cubic boron nitride. (3) Mix high-pressure phase type boron nitride powder, one type of powder of iron group metal, or a mixed powder of two or more types of powder, or compound powder, At powder, and Cu powder, and after molding into powder or molding, use an ultra-high pressure apparatus. using a pressure of 20 Kb or more and a temperature of 900
Contains high-pressure phase type boron nitride characterized by sintering at a temperature of 75 cm or more and 95 cm or less by volume, and the At content is 5 cm or more by weight or more and 5 cm or more by weight. 45
% or less, a method for manufacturing a high hardness sintered body for tools. (4) The method for manufacturing a high-hardness sintered body for tools according to claim (3), wherein the high-pressure phase boron nitride is cubic boron nitride. (5) Mix high-pressure phase type boron nitride powder and At powder, mold it into powder form or mold it, and then sinter it using Chotakada equipment I/L at a pressure of 20 Kb or more and a temperature of 900°C or more, and then externalize the sintered body. A method for manufacturing a high-hardness sintered body for a tool according to claim (3) or (4), wherein a ferrous metal and Cu or an alloy of an ferrous metal and Cu are infiltrated into the sintered body.

Claims (1)

[Claims] (1) High-pressure phase type boron nitride containing 75% or more by volume of 95-
The remainder is made of an alloy of iron group metals and Mu4Gu, and the content of iron group metals in the remainder is 25-90 or more per lid.
Is or less, the Mut content is 5% or more and 50% or less by weight, and the Ou content is 5% or more and 4% or less by weight.
l1i1i hardness sintered body for tools characterized by being less than 5-threshold The above-mentioned high pressure phase type boron nitride is cubic crystal nitride 4#
The high hardness sintered body for tools according to claim (1), which is I element. <3) High-pressure phase type nitrided slate powder and iron group metal powder or mixed powder of two or more powders or compound powder and Ou powder are mixed, and this is made into powder form or after extrusion molding. When sintered using a high-pressure device at a pressure of 20 It or higher and a temperature of 900C or higher, a characteristic high-pressure phase is produced!
! ! ! A high-hardness sintered body for tools, which contains 75% or more and 95% or less of wood by volume, and the content of iron group metals in the remainder is 5162 or more and 4591 or less by weight. manufacturing method. (4) The method for producing a high-hardness sintered body for tools according to claim 0), wherein the high-pressure phase boron nitride is cubic boron nitride. (Xun) Mix high pressure phase type nitrided borium powder and powder.
Pressure 2 using ultra-ultra high pressure equipment for powder or Fi type extrusion molding
Claim (2) or O in which the sintered body is sintered at a temperature of 900°C or higher and the iron group metal and Cu or the alloy of the iron group metal and O are infiltrated into the sintered body from the outside of the sintered body. ) A method for manufacturing a high-hardness sintered body for tools.