JPS6020458B2 - High-toughness boron nitride-based ultra-high pressure sintered material for cutting and wear-resistant tools - Google Patents

Description

Detailed Description of the Invention This invention has particularly excellent ballability and wear resistance, high hardness, and excellent heat resistance and high temperature strength, and is suitable for use in high-speed steel and other steels that require these properties. , Ni or Co
The present invention relates to a nitride-based ultra-high-pressure cutting material suitable for use as a cutting tool for work materials such as super alloys, and as wear-resistant tools such as bearings and wire drawing dies.

In recent years, cubic crystal nitride shelbase-based ultra-high-pressure abrasive materials (hereinafter referred to as CBN-based ayo-stripe materials), which have extremely superior wear resistance compared to tungsten carbide-based abrasive materials, have been used as cutting tools and wear-resistant tools. It is proposed to do so. This CB
N-based sintered twill materials can be roughly divided into two types depending on the binder phase of the CBN particles that form the dispersed phase, one of which is one in which the binder phase is composed of an iron group metal or a metal whose main component is N or the like. The other is titanium nitride, titanium carbide,
The binder phase is made of a ceramic compound whose main component is aluminum nitride or aluminum oxide.

However, in the former, since the binder phase is metal as mentioned above, it easily softens at high temperatures, and therefore, when used as a cutting tool, for example, it can withstand severe cutting conditions that generate a large amount of heat. Due to insufficient abrasiveness, sufficient cutting performance cannot be expected, and under conditions with little heat generation,
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 heat resistance and wear resistance, but on the other hand, lack of toughness cannot be avoided. For example, 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. Also,
In order to solve the respective problems of the above two types of conventional CBN materials, a CBN-based binding material in which the binder phase is composed of a metal and a ceramic compound has been proposed. Similarly, when used as a cutting tool under cutting conditions where a large impact force is applied to the cutting edge, such as when milling high-speed steel, the cutting edge tends to break.

This was revealed through detailed observation using a scanning electron microscope of the boundary between the CBN particles and the binder phase (metal/ceramic compound) in the above-mentioned CBN-based material. At the time of dawn fringes, fine unbonded parts (voids) are formed at the boundary part due to the binder phase not being sufficiently wrapped around the fine concave parts on the surface of the CBN particles, and The adhesion between CBN particles and the binder phase varies depending on the constituent components of the binder phase, but it is particularly low in the case of carbide-based ceramics, which means that there are parts of the bond between the CBN particles and the binder phase that have weak bond strength. It is understood that this is caused by the formation of Therefore, from the above-mentioned viewpoint, the inventors of the present invention aimed to obtain a CBN-based cemented material that has particularly excellent rutting resistance and wear resistance. One or two of AI and Si as bond-strengthening metals: 2
~25% by weight, aluminum oxide: 2-3% by weight, silicon nitride: 2-3% by weight, and the remainder consists of CBN (cubic shebal nitride) and inevitable impurities, and Assuming that CBN occupies 40 to 90% by volume and that the bond-strengthening metal has a structure in which the CBN is surrounded by an average layer thickness of 0.1 to 1.5 cm, the carbon that constitutes the dispersed phase
AI and Si, which act as bond-strengthening metals surrounding the BN particles, have good wettability with the CBN particles, and react with impurities such as oxygen, water, and oxides attached to the surface of the CBN particles, and remove them. and clean it, and then pre-clean it with C when preparing the raw material.
The surface of the BN particles is strongly and densely coated using methods such as electroless coating, chemical vapor deposition (CVD), physical vapor deposition (PVD), and plasma chemical vapor deposition (PCVD). Therefore, there is no unbonded part (void) at the boundary between the CBN particles and the surrounding layer of N and Si, and on the other hand, aluminum oxide (hereinafter N2
03) and silicon nitride (hereinafter referred to as Si3N4)
Since the CBN particles and the binder phase are mutually diffused in the surface layer, the CBN particles and the binder phase are strongly bonded through N and/or Si, and as a result, the material has extremely high quality. In addition, not only the excellent wear resistance and high hardness are ensured by the CBN particles and AI203, but also the high temperature properties and thermal shock resistance are improved by the inclusion of Si3N4. When a material contains one or more metal components of Ni, AI, Co, Si, and Cr in a range of 0.5 to 1% by weight, these components have a bonding phase. Because it has the effect of strengthening the bonding force, the material becomes more delicate,
Furthermore, a portion of the CBN in the CBN-based competitive material is set within a range that does not exceed the CBN, that is, 0. 〇5<Wultz-key type nitride shelving unit C capacity%) <ICBN (volume%)
They found that when the material was replaced with (shown by ), the rutting properties of the material were further increased.

This invention was made based on the above knowledge, and the following is the component composition, the volume ratio of CBN and WBN,
Also, the reason why the layer thickness of the bond reinforcing metal is limited as described above will be explained.

A Component composition 'a} N and Si AI and Sj components have the effect of strongly bonding with the CBN particles and WBN particles as well as the needles 203 and Si3N4 as binder phase forming components to significantly improve the toughness of the material. However, if the content is less than 2% by weight, the desired bond-strengthening effect cannot be ensured, while if the content exceeds 25% by weight, the high-temperature hardness in particular decreases. Its content was determined to be 2 to 25% by weight.

'b} Mountain 203 N203 has the effect of improving the wear resistance of the material, but if its content is less than 2% by weight, the desired excellent wear resistance cannot be obtained; If the content exceeds 100%, the heat resistance properties will deteriorate, so the content was set at 2 to 3% by weight.

W Si3N4 Si3N4 has the effect of improving high-temperature properties and thermal shock resistance, but if the content is less than 2% by weight, the desired effect cannot be obtained, while if the content exceeds 3% by weight, Since the abrasion resistance deteriorates when the content is included, the content is determined to be 2 to 3 weight %.

'd'Ni, N, Co, Si, and Cr These metal components have the effect of densifying the binder phase and further improving the strength and impact resistance of the material, so these properties are particularly important. It is included as necessary when required, but if the content is less than 0.5% by weight, the desired effect cannot be obtained, while if it is included in excess of 1% by weight, the hardness decreases. Since the content becomes significant, its content is reduced to 0.5
~1% by weight.

B Volume percentage of CBN When the ratio of CBN to the binder phase is less than 4% by volume, the ratio of relatively hard CBN is too small to ensure the desired wear resistance, while on the other hand, when the ratio of CBN is 90 If it exceeds 40% to 9% by volume, the proportion of the binder phase becomes relatively too small, resulting in a decrease in ballistic properties, so the volume proportion was set at 40 to 9% by volume.

C WBN substitution ratio WBM This has the effect of further improving the quality of the material, so when particularly high toughness is required, CBN may be added as needed.
is contained in a partially substituted form, but the substitution ratio, that is, WBN (volume %) / CBN (volume %) is 0.05.
If the substitution ratio is less than 1, the desired effect of improving sardine properties cannot be obtained. On the other hand, if the substitution ratio exceeds 1, that is, there is relatively more WBN than CBN, the hardness of the material decreases, and the wear resistance decreases. As the
When replacing with , the condition o-o5<Chinese poem<・ must be satisfied.

○ Average layer thickness of N and Si as bond-strengthening metals If the average layer thickness is less than 0.1, CBN particles and WB
It is not possible to secure sufficient bonding strength between the N particles and the binder phase, and on the other hand, if the average layer thickness exceeds one layer thickness, the hardness of the material will decrease. The thickness was determined to be 0.1 to 1 French.

The ultra-high-pressure mackerel feed material of the present invention is produced by first applying a method such as an electroless finishing method, a CVD method, a PVD method, or a PCVD method to the surface of the CBN powder and, if necessary, the WBN powder. Coating AI and/or Si as a bond-strengthening metal with an average layer thickness of 0.1 to lrm, and further coating thereon as a bonding phase-forming component with a back layer of mountain 203 and/or Si3N4 as necessary, CBN powder and WBN powder coated with a bond-strengthening metal prepared in this way, CBN powder and WBN powder coated with a bond-strengthening metal and a binder phase forming component in multiple layers, and AI2Q powder, S
i3N4 powder, Ni powder, Co powder, AI powder, Si powder, Cr powder, and alloy powder of two or more of these metals are prepared as raw material powders, and a predetermined composition is prepared by appropriately selecting from these raw material powders. After mixing this blended powder under normal conditions, it is placed in a metal container together with a superalloy plate, etc. as necessary in the powder state or in the form of powder, vacuum degassed, and sealed. Next, take this sealed container.
For example, it is attached to an ultra-high pressure and high temperature generator as described in Samurai Publication No. 36-123463, and the pressure and temperature are increased.
Manufactured by a basic process consisting of maintaining the pressure and temperature within the range of pressure: 40 to 7 cm, temperature: 1200 to 1600 q0 for several minutes to several tens of minutes, cooling, and finally releasing the pressure. be able to.

Next, the ultra-high pressure Akatsuki silk material of the present invention will be specifically explained using Examples.

Example 1 Using the known PVD method and CVD method, the first
The coated CBN powders and coated WBN powders shown in the table were prepared, and these coated powders had an average grain size of 2r.
I203 powder, Si3N4 powder with the same 2r, Ni powder, AI powder, Co powder, all with the same 2A,
Si powder and Cr powder are each prepared as raw material powders, and these raw material powders are blended into the compositions shown in Table 1, and these blended powders are heated in a ball mill for about 20 minutes.
After wet mixing for an hour, it is dried, and then the mixed powder is packed together with a cemented carbide plate with dimensions of 12.5 mm x 1.5 mm and placed in a vacuum chamber. After degassing and sealing, this sealed container was placed in a known ultra-high pressure and high temperature generator and heated under the following conditions: pressure: 5cm, temperature: 130cm, holding time: 1cm. By the basic process consisting of final cooling and gradual pressure reduction, the ultra-high pressure deposited materials 1 to 19 of the present invention were produced, respectively, with a final component composition substantially the same as the formulation composition.

Next, the ultra-high pressure Akaya material 1 of the present invention obtained as a result
~19, work material: die steel (SKD-11, hardness: HRC60), cutting speed: 100/min, feed: 0.1 skin/rev. A cutting test was conducted under the conditions of , depth of cut: 0.5 feet, and no cutting oil.

In addition to measuring the cutting time until the flank wear of the cutting edge reaches 0.2 skin, we also cut two U-grooves with a diameter of 4 mm x 4 mm deep along the longitudinal direction of the workpiece at mutually symmetrical positions. This book has an outer diameter of 13 mm? die steel round bar (SKD-61, hardness: HR
C52), cutting speed: 100 m/min, depth of cut: 0.
5 legs, feed: 0.05, 0.1, 0.150.2, 0.
3 and 0.4 skin'rev. , cutting time for each feed:
An intermittent cutting test was conducted for 2 minutes without cutting oil.
The feed amount was checked at the time when chipping was observed on the cutting edge. The cutting test results are shown in Table 1 along with the Vickers hardness. S Ship S Ship In Table 1, the dispersed phase is composed of CBN, but there are commercially available ultra-high pressure condensed materials with different binder phases, that is, metals in which the binder phase is made of AI-Co. The composed material (
(hereinafter referred to as conventional ultra-high pressure sintered material 1), and the binder phase is T
The results of a cutting test under the same conditions for a material made of ICN's ceramic compound (hereinafter referred to as secondary ultra-high pressure lather material 2) are also shown.

As shown in Table 1, the ultra-high pressure material 1 to 1 of the present invention
No. 9 has both excellent wear resistance and toughness, so it shows excellent cutting performance in all cutting tests, whereas conventional ultra-high pressure It is clear that the brazed materials 1 and 2 do not show satisfactory results in both tests.
As mentioned above, the ultra-high pressure sintered material of the present invention has excellent wear resistance, plowability, and high hardness, as well as excellent heat resistance and high-temperature strength. It exhibits excellent performance not only as cutting tools, but also as wear-resistant tools such as bearings and wire drawing dies.

Claims (1)

[Claims] 1. One or two of Al and Si as bond-strengthening metals: 2 to 25% by weight, aluminum oxide: 2 to 25% by weight.
30% by weight, silicon nitride: 2 to 30% by weight, and the remainder consists of cubic boron nitride and inevitable impurities,
In addition, cubic boron nitride occupies 40 to 90% by volume, and the bond-strengthening metal accounts for 0.1 to 90% of cubic boron nitride.
A high-toughness silicon nitride-based ultra-high pressure sintered material for cutting and wear-resistant tools, characterized in that it has an enclosed structure with an average layer thickness of 1 μm. 2 One or two of Al and Si as bond-strengthening metals: 2-25% by weight, aluminum oxide: 2-25% by weight
30% by weight, silicon nitride: 2 to 30% by weight, further containing one or more of Ni, Al, Co, Si, and Cr: 0.5 to 10% by weight, and the remainder It has a composition consisting of cubic boron nitride and unavoidable impurities, and the cubic boron nitride accounts for 40 to 90% by volume, and the bond-strengthening metal has a cubic boron nitride content of 0.1 to 1 μm.
A high-toughness boron nitride-based ultra-high pressure sintered material for cutting and wear-resistant tools, characterized by having an enclosed structure with an average layer thickness of m. 3 One or two of Al and Si as bond-strengthening metals: 2 to 25% by weight, aluminum oxide: 2 to 3
0% by weight, silicon nitride: 2 to 30% by weight, the remainder having a composition consisting of cubic boron nitride, wurtzite boron nitride, and inevitable impurities, and containing cubic boron nitride and wurtzite boron nitride. It accounts for 40-90% by volume, and
0.05<wurtzite boron nitride (volume %)/cubic boron nitride (volume %)<1; ~
A high-toughness boron nitride-based ultra-high pressure sintered material for cutting and wear-resistant tools, characterized by having an enclosed structure with an average layer thickness of 1 μm. 4 One or two of Al and Si as bond-strengthening metals: 2-25% by weight, aluminum oxide: 2-25% by weight
30% by weight, silicon nitride: 2 to 30% by weight, further containing one or more of Ni, Al, Co, Si, and Cr: 0.5 to 10% by weight, and the remainder It has a composition consisting of cubic boron nitride, wurtzite boron nitride, and inevitable impurities, and cubic boron nitride and wurtzite boron nitride account for 40 to 90% by volume, and 0.
．． 05<wurtzite boron nitride (volume %)<cubic boron nitride (volume %)<1;
A high-toughness boron nitride-based ultra-high pressure sintered material for cutting and wear-resistant tools, characterized by having an enclosed structure with an average layer thickness of μm.