JPS593072A - Sialon base sintered material for cutting tool and antiabrasive tool - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to high strength sialon-based sintered materials that exhibit excellent wear resistance, particularly when used as cutting tools and wear-resistant tools.

SiOy consisting of a solid solution of silicon nitride and aluminum oxide (Sig-zAlzozNs-z(0<z≦5
), it is one of the materials that has been attracting attention in recent years because of its high hardness, low coefficient of thermal expansion, high oxidation resistance, and excellent thermal shock resistance.
However, the fact that it is an extremely difficult-to-sinter material has been a major obstacle in putting it into direct use.

However, recently, yttrium oxide (hereinafter referred to as Y
*Os) was found to act as an excellent sintering aid for the above-mentioned sialon trap, with the sialon as the main ingredient and 0.
The sialon-based sintered material sintered with an additive of 2 to 10% (hereinafter, % is expressed as an electrical standard) has thermal stability up to a high temperature range, and has excellent oxidation resistance and thermal shock resistance. It has been found that this material also has the same properties as that of other materials, and attempts are being made to use this material as cutting tools and wear-resistant tools1.
However, in the conventional sialon-based sintered materials,
For example, when used as a cutting tool to cut cast iron, the heat and load applied to the cutting edge are lower than when cutting steel, so it exhibits relatively good wear resistance, but the rigid material When the material is made of steel, not only does the cutting resistance that causes heat generation increase, but the bonding force between the particles in the sialon-based sintered tung material itself is still insufficient, making it easy for the cutting edge to peel off. At present, it suffers from significant wear and cannot be put to practical use.

From the above-mentioned viewpoints, the present inventors have discovered that although it is thermally stable up to high temperature ranges and has excellent oxidation resistance and thermal shock resistance, when used as a cutting tool for cutting steel, for example, it suffers from wear. Focusing on the above-mentioned conventional sialon-based sintered material, which is extremely unsuitable for practical use, we conducted research to provide it with excellent wear resistance. They found that by adding an appropriate amount of Sialon (shown below), the wear resistance can be significantly improved without impairing the properties of Sialon.

This is because TIBz itself is extremely hard (Vickers hardness Hv): 3200Ky/rrtr? J, In addition to showing good values in terms of oxidation resistance and corrosion resistance and having excellent thermal stability, it also has extremely good bonding properties with sialon particles, so YG os containing YG-OS with an appropriate amount of K added thereto. The sialon-based sintered material is [-sialon+Y*Os
This is because the T18g particles have a three-phase structure of 10 TiBzJ, and the highly hard TiBg exists in a stable and finely dispersed state, and the bond between the T18g particles and the surrounding phase is extremely strong. It is written as ``.

This invention was made based on the above knowledge, and includes a Sialon-based sintered material containing: YOs: 0.2 to 1096, TiBz: 5 to 40%, Sialon and unavoidable impurities: the remainder As a composition consisting of , it is characterized in that it is used for cutting tools and wear-resistant tools.

Next, the reason why the composition range of the sintered material of the present invention is set to the above-mentioned range will be explained.

lal Y* to Y! 0m Component Vr forms a yttrium silicate liquid phase during sintering to promote densification of the sintered body, acts as a sintering aid, and has a high melting point of 1850°C or higher. Melilite type compound (S l s N4 Ys
It has the effect of precipitating the crystalline phase of Os) at the grain boundaries and increasing the high temperature strength of the sintered material, but if its content is less than 0.2%, the desired effect cannot be obtained on the Mori effect. If the content exceeds 0.2%, the properties provided by Sialon, especially thermal shock resistance and abrasion resistance, cannot be fully exhibited.
I added 10%.

When the lbJ T I Btx TiB snow component is added to the Sialon solid solution,
A small portion of the bound B reacts with the acid deposits on the sialon base to form a room, which strengthens the grain boundaries of the sintered material and improves its wear resistance. . Furthermore, as mentioned above, TIB snow itself is extremely hard and has excellent thermal stability, so it will not impair the characteristics of Sialon if added in the appropriate amount. If the amount is less than 5%, the desired effect cannot be obtained, while if the amount is more than 40%,
Sialon wrinkles are relatively reduced too much and the thermal shock resistance of the sintered material deteriorates, so its inclusion! l
was set at 5-40%.

The sintered material of the present invention can be manufactured according to the usual powder metallurgy method, but in particular, the following method is used: First, SiAlON powder, or 81sNa, AA!
N and AA! *Om mixed powder, Y2O3 powder and T
IB! Blend with powder to form a composition of PIr foot,
After heating under normal conditions and forming into a green compact, it is sintered under normal pressure at a temperature within the range of 1700 to 1800C in a nitrogen atmosphere, or hot pressed. It will be done. Further, if necessary, the obtained sintered body is further heated at a temperature of 1600 to 1800°C and a pressure crab 1
Hot isostatic pressing (HIP) at 000-2000 atm
), it is possible to obtain a good sintered body that is more dense up to the center.

In addition, so-called sialon solid solution (Si6-zAlzO
zN, -, ) exists in a wide range of binary values from 0 to 5, and the properties partially change depending on the value. It also has great characteristics in that it has characteristics for tools by taking advantage of its oxidation resistance, and although it is necessary for the Z value to exceed 0,
If it exceeds 3tl, the ratio of AI and O is relatively large, and both transverse rupture strength and abrasion resistance decrease, and furthermore, 5i
This is not desirable because the thermal shock resistance value of sN4 cannot be utilized.

Next, the sintered material of the present invention will be specifically explained with reference to Examples.

Example First, raw material powders were all commercially available with an average particle size of 0.
51mNi powder with 6μm, 0*411m(Dk
l*Os powder, 1.2 μm klN powder, 0.47
1m of Y*Os powder and 0.8μm of TiBs
Prepare powders, blend these raw powders into the composition shown in Table 1 that corresponds to the composition of the target sialon-based sintered material, mix in a wet ball mill, dry, and pressurize at a pressure of 1 t/-. This compacted powder is inserted into a graphite mold with the upper and lower sides sandwiched with boron nitride powder,
Sintered materials 1 to 18 of the present invention and comparative sintered materials 19 to 26 having substantially the same composition as the blended composition were hot pressed at 1750C for 30 minutes in a nitrogen atmosphere. manufactured respectively.

Next, the density, hardness (Rockwell hardness A scale), and transverse rupture strength of the various sintered materials obtained as a result were measured, and from this, a cutting tip (SNP432 type) was measured.
Cut out, work material: SNCM-8 (hardness: Hm27
0), Cutting speed: 300m/w, Feed V: 0.2111
7rev, cutting depth: 1.5m1. A high-speed cutting test of steel was carried out under the condition of cutting time: 2 sm, and the flank wear width (relief face wear width of the cutting edge: Vs+) was measured. The results of these foot measurements are also shown in Table 1.

From the results shown in Table 1, sintered materials 1 to 18 of the present invention all have higher hardness than conventional sintered materials or comparative materials 19 to 26 whose composition ranges are outside the range of the present invention. It is clear that it has high toughness and exhibits excellent abrasion resistance when used as a cutting tool.

As mentioned above, the sintered material of the present invention has particularly excellent toughness and wear resistance, and has excellent high-temperature strength, oxidation resistance, and thermal shock resistance, as well as thermally stable properties even in high-temperature ranges. Therefore, when used as cutting tools that require these characteristics, or wear-resistant tools such as bearings and wire drawing dies, they exhibit excellent performance over a long period of time.

Applicant: Mitsubishi Metals Corporation Agent Tomi 1) Kazuo

Claims (1)

[Claims] Contains yttrium oxide = 0.2 to 10%, titanium boride = 5 to 40%, Sialon and unavoidable impurities: remaining 9 (by weight)
A sialon-based sintered material for cutting workers and wear-resistant tools, characterized by having a composition consisting of: