JPS58145676A - Surface-clad silicon nitride base sintered member for high speed cutting 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 has excellent abrasion resistance and thermal shock resistance.

The present invention also relates to a surface-coated silicon nitride-based sintered member that has high-temperature strength and exhibits excellent cutting performance when used as a cutting tool for high-speed cutting of steel and cast iron, which particularly require these properties.

In recent years, various research and development efforts have been made to enable high-speed cutting of steel and cast iron as rigid materials. The transition to cutting is steadily being achieved, and at present one of the goals is stable cutting at a high cutting speed of 300 to 600 m/mjn.

The above-mentioned high cutting speed is achieved by using aluminum oxide (hereinafter referred to as A9□03), which has excellent oxidation resistance against the heat generated during high-speed cutting, has low chemical reactivity with Fe, and has a small friction coefficient. A containing as a main component
It was determined that this can be achieved by improving machine tools to enable high-speed cutting, on the premise that e203 sintered materials will be used as cutting tools.

However, the above M2O3-based sintered material does not have sufficient thermal shock resistance and mechanical strength at high temperatures, so it is used as a cutting tool, especially for cutting steel.
When used at high cutting speeds of ~600m/mI7+,
Coupled with the fact that machine tools have not yet been sufficiently improved, stable cutting performance cannot currently be achieved.

On the other hand, silicon nitride (hereinafter referred to as Si3N4) and 513N4, which have a small coefficient of thermal expansion, that is, excellent thermal shock resistance and excellent mechanical strength at high temperatures,
20. Xialon (hereinafter referred to as 5i3) consisting of a solid solution of
The main component is N4 (denoted as A Kita 203)), and also contains yttrium oxide (hereinafter referred to as ¥203), magnesium oxide (hereinafter referred to as MgO), and silicon oxide (hereinafter referred to as 5102).
), aluminum nitride (hereinafter referred to as AQN),
Titanium oxide (hereinafter referred to as TlO2).

An 813N 4-based sintered material containing 1 to 30 by weight of a binder phase forming component consisting of one or more of zirconium oxide (hereinafter referred to as ZrO) and hafnium oxide (hereinafter referred to as HfO□). Attempts have also been made to use this Si3N-based sintered material as a cutting tool for high-speed cutting of steel and cast iron, but this Si3N-based sintered material has high reactivity with Fe, so it wears severely, especially when cutting steel at high speed. , it has extremely low versatility as a cutting tool.

Therefore, from the above-mentioned viewpoints, the present inventors have discovered that although the tool has excellent thermal shock resistance and high-temperature strength, when used as a cutting tool especially for high-speed cutting of steel, it suffers from severe wear and cannot be put to practical use. Focusing on the conventional 813N4-based sintered material, we conducted research to give it excellent wear resistance.As a result, we found that silicon nitride (hereinafter referred to as (Si)) was added to the base surface of the conventional Si3N4-based sintered material. silicon oxynitride (hereinafter referred to as (Si)ON), silicon carbonitride (hereinafter referred to as (Si)ON), silicon oxynitride (hereinafter referred to as (Si)ON),
Sj,) denoted by CN).

Silicon carbonate nitride (hereinafter referred to as (Si)CON), At
! Solid solution silicon nitride (hereinafter referred to as (Si, A+N)), AA solid solution silicon oxynitride (hereinafter (Si, AA) O)
Nf), AQ solid solution silicon carbonitride (hereinafter (si, A
Q)c''N), and AQ, solid solution silicon carbonate nitride (hereinafter referred to as (Si, AM)CON, - the above components are collectively referred to as 5i-N compounds). A chemical vapor deposition film consisting of a single layer of seeds or a multilayer of two or more seeds is 05
When coated with an average layer thickness of ~10.0 μm, the 5i-N
The chemical vapor deposited film of the based compound has extremely high adhesion to the substrate surface and has excellent wear resistance.
The resultant surface-coated Si3N4-based sintered member can be used as a cutting tool for cutting steel and cast iron.
In order to stably exhibit outstanding cutting performance in high-speed cutting of 0 m 1 m 1 nm or more, a chemical cap of the above-mentioned 5i-N compound is added as necessary. Layer 05-50
When coated with an average layer thickness of μm, this A2203 layer has high adhesion strength with the 5i-N compound layer, and
Since the 03 layer exhibits excellent oxidation resistance and wear resistance during high-speed cutting, it was discovered that the tool life can be further extended.

This invention was made based on the above findings, and the reason why the component composition of the substrate and the average layer thickness of the 5i-N compound film and the AQ203 film were limited as described above will be explained below.

(a) Component composition of the substrate Y2O3, MgO, 5i02. AQN, TiO2
, ZrO2, and HfO2 have the effect of improving the sinterability and toughness of the substrate, but if their content is less than 1 weight φ, the desired effect cannot be obtained; If the content exceeds 30% by weight, the relative
If the content of t3N4 and 5i3N4 (A1203) becomes too low, the thermal shock resistance and high temperature strength of the substrate will decrease, so the content should be reduced from 1 to 30 6
- Defined as weight department.

(b) Average layer thickness of Si-N compound As mentioned above, the chemical vapor deposition film of 5i-N compound is
Since the bonding force of the 3N4 base sintered material with the substrate surface is extremely strong and it has excellent wear resistance, the Si3N4 base sintered member coated with the chemical vapor deposition film of the 5i-N compound is It exhibits excellent wear resistance not only in cast iron cutting but also in high-speed cutting of steel. However, if the average layer thickness is less than 0.05 μm, the desired wear resistance cannot be secured; on the other hand, if it exceeds 10.0 μm, Even if the layer thickness is made thicker, the effect of further improving wear resistance cannot be obtained, so the average layer thickness is set at 05 to 10.0/Zm.

(Average layer thickness of CI At!203 As above, A
The chemical vapor deposited film of 9203 has a very strong bond with the chemical vapor deposited film of the Si-N compound mentioned above, and also has excellent oxidation resistance and wear resistance.
By forming an AQ203 film as an outer layer, the cutting life can be further extended, but if the average layer thickness is less than 0.5 μm, the desired improvement effect cannot be obtained.
On the other hand, if the thickness exceeds 5.0 μm, the toughness of the member itself will decrease, so the average layer thickness should be adjusted to 0.5 to 5 μm.
It was set as 0 μm.

Furthermore, the surface coating S1 of this invention. The sintered base of the N4-based sintered member is made by blending raw material powder into a predetermined composition,
It can be manufactured by mixing and applying normal sintering or hot pressing, in which case the substrate has a transverse strength of near 0 kg/- or more.

It has a Vickers hardness of 1,600 kg/- or more, and the chemical vapor deposition film of the 5i-N compound and Ag, 203 coated on the surface of the substrate is formed by a normal chemical vapor deposition method (preferably a plasma chemical vapor deposition method). According to the reaction gas, chlorosilane.

Methyl chloride silane, monosilane, ammonia, N2 gas, aluminum trichloride, acetylene, methane.

By using CO gas, CO2 gas, H20, and N2 gas as a gear gas, and by appropriately selecting and combining these reaction gases, one layer or two or more layers of a predetermined composition can be formed.

Next, the surface-coated Si3N4-based sintered member of the present invention will be specifically explained with reference to Examples.

All of the raw material powders used in the examples had commercially available average particle diameters of ~2 μm.
Y2O3 powder, MgO powder, 5in2 powder with.

AQN powder, TiO2 powder, ZrO2 powder, Hf
○2 powder + 513N4 powder, and 5i3N4 (Al2
O3) Prepare powder, mix these raw material powders to the composition shown in Table 1, mix thoroughly in a wet ball mill, dry, and then use a graphite mold at a temperature of 1700.
~1900℃, pressure crab 100~250 kg/ffl
, retention time.

By hot pressing for 30 to 60 minutes,
Si3 having a final component composition substantially the same as the formulation composition
After manufacturing an N4-based sintered material base and then grinding the base to obtain a cutting tip of the ISO standard 5NO-N432 type, a prescribed honing is performed on the cutting edge, and subsequently using a known chemical vapor deposition device, 81-N compound film and AM203 having the materials and average layer thickness shown in Table 1, respectively.
Surface-coated cutting chips 1 to 23 of the present invention were manufactured by forming a film. Incidentally, five types of cutting chips without surface coating were prepared as comparison cutting chips 1 to 5.

Then, the surface-coated cutting tip of the present invention obtained as a result]
~23 and comparative cutting tips 1 to 5, workpiece material:
SNCM-8 (Brinell hardness: 2'70).

Cutting speed: 300 m/mm, depth of cut: ], 5
Steel high-speed continuous cutting test under the conditions of mm+feed: 0.35 g/rev.

And work material: FC-25 (Brinell hardness: 150)
.

Cutting speed: z5om7m=, Feed: 0.25m@/
rev.

A cast iron high-speed continuous cutting test was conducted under the condition of cutting depth: 2 mm, and the life time until the flank wear width reached 0.3 m was measured. These measurement results are also shown in Table 1.

As is clear from the results shown in Table 1, surface-coated cutting inserts 1-23 of the present invention have excellent wear resistance, thermal shock resistance, and high-temperature strength, so they can be used for high-speed cutting of steel and cast iron. In contrast, Comparative Cutting Tips 1 to 5, which have poor wear resistance due to extensive chemical vapor deposition film formation, only show relatively short cutting lives. There isn't.

As described above, according to the surface-coated Si3N4-based sintered member of the present invention, the base body ensures excellent thermal shock resistance and high-temperature strength, and the bonding strength with the base surface and the AQ, 03 coating as the outer layer are maintained. Excellent wear resistance is ensured by the Sj, -N-based compound film, which has an extremely strong bonding force with the AQ203 film, and it is suitable for cutting tools for high-speed cutting of steel and cast iron, which require these properties. When used as a cutting agent, industrially useful effects such as extremely excellent cutting performance can be achieved stably over a long period of time.

Applicant: Mitsubishi Metals Corporation Agent Tomi 1) Kazuo

Claims (2)

[Claims] (1) One or more of yttrium oxide, magnesium oxide, silicon oxide, aluminum nitride, titanium oxide, zirconium oxide, and hafnium oxide: 1 to 30 weight coefficients, with the remainder being silicon nitride. Silicon nitride, silicon oxynitride, silicon carbonitride, silicon carbonate nitride, AA solid Consisting of a single layer or a multilayer of two or more of the following: silicon nitride in solution, NV, silicon oxynitride in solid solution, silicon carbonitride in 1M solid solution, and silicon carbonitride in M solid solution A surface-coated silicon nitride-based sintered member for a high-speed cutting tool, which is coated with a chemical vapor deposition film with an average layer thickness of 05 to 10.0 μm. (2) In the surface-coated silicon nitride-based sintered member according to claim 1, on the chemical vapor deposition film,
A surface-coated silicon nitride-based sintered member for a high-speed cutting tool, further comprising a chemical vapor deposition film of aluminum oxide with an average layer thickness of 05 to 50 μm as an outer layer.