JPS6284905A - Manufacture of surface coated ceramics tool - Google Patents

Abstract

PURPOSE:To obtain a tip of long life in excellent wear resistance removing a denitrified layer and a bore to disappear, by applying a heating and pressurizing process under a specific condition to a surface coated tool of material based from ceramics of silicon nitride radial or silicon radial. CONSTITUTION:A tool of material, based from ceramics of Si3N4 radical or sialon radical, applies as a hard layer a film of a single layer of one kind or plural layers of two kinds or more of TiC, TiN, TiCN, TiCO, TiCNO, Al2O3, AlNO, and a heating and pressurizing process is applied to the tool by holding it in the atmosphere of N2 at 10kg/cm<2> ore ore at a temperature of 1,100-1,650 deg.C for 50-60min. In this way, the hard layer, through which N2 in the atmosphere diffuses in a base unit surface part to react with free Si and form Si3N4, removes a denitrified layer to disappear, while a fine bore disappears by forming the Si3n4, removes a denitrified layer to disappear, while a fine bore disappears by forming the Si3N4 through volume expansion with also a coarse bore disappearing by the ambient pressure, and the surface comes to provide toughness equal to a base unit internal part. Disappearance of the bore and the denitrified layer causes adhering strength to increase, as the result wear resistance and a life are improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention has no defects at the interface between a substrate and a hard layer, that is, there is no denitrification layer or bore on the substrate surface, and therefore the substrate surface has no defects. The present invention relates to a method for manufacturing a surface-coated ceramic tool in which the hard layer does not deteriorate in toughness and the adhesion strength of the hard layer to the substrate surface is extremely high.

[Conventional technology]

Conventional - In general, lMgO, Y2O3, lanthanide rare earth element arsenide, A7203, etc. are used as the binder phase.
Contains one or more of MN, SiO2, etc. - if necessary (as a dispersed phase).

For example, TiC+TiN*TlB2+T+CN
O+ ZrN * ZrO2 + HfC * VC * Tooth C
* A group consisting of carbides, nitrides, oxides, and borides of metals in groups 4a, 5a, p and 6a of the periodic table, such as TaCr TaN 9Mo2C+ and WC, and solid solutions of two or more of these. Contains one or more of these, and the remaining main component is S as a hard phase.
i 3N4 or Sialon (α Sialon and/or
or β-sialon)
A base ceramic or a sialon base ceramic is used as a base, and the surface of this base is TiC, TiN s T1C.
A surface-coated ceramic tool coated with a hard layer consisting of a single layer or a multilayer of two or more of N, TiC0, TiCN0 + Al2O2°, and AgNo is used as a cutting tool, a wear-resistant tool, etc. It is well known that there are.

[Problem that the invention seeks to solve]

However, the above-mentioned conventional surface-coated ceramic tools can be put into practical use as cutting tools, wear-resistant tools, etc.
The hard layer was prone to chipping and peeling, and the service life was reached in a relatively short period of time.

[Means for solving problems]

Therefore, the present inventors focused on the above-mentioned conventional surface-coated ceramic tools, and conducted research to extend the service life of the tools when used as cutting tools or wear-resistant tools. Surface-coated ceramic tools (
2) Chips and peeling occur on the tool surface (1) when forming a hard layer on the base surface by, for example, chemical vapor deposition, Si3N or Nylon (St- M-0-N)E decomposition occurs, and not only a denitrification layer is formed on the surface of the substrate, but also a bore is formed at the interface with the hard layer, and as a result, the substrate It was found that the cause was a decrease in the toughness of the surface and a decrease in the adhesion strength of the hard layer to the substrate surface. Based on these results, further research was conducted and one substrate was S f 3N4-based ceramics or sialon-based ceramics (knee) This surface (= the hard layer to be coated is TiCe Ti
N*T1CN*TiC0+TiCN0, U
For surface-coated ceramic tools specified as a single layer of one type or a multilayer of two or more types of 2O55* and AgN0 (7), N with a pressure of 10 Kf/d or more is added.
2 Temperature of 1100-1650'C in atmosphere; 2, 5
When heated and pressurized for ~60 minutes, N2 in the atmosphere diffuses to the surface of the substrate through the hard layer and reacts with free Si present on the surface of the substrate to form Si3N4, resulting in desorption. The nitrogen layer disappears.

In addition, fine bores disappear due to volume expansion due to the formation of Si3N4, and relatively coarse bores disappear due to atmospheric pressure, so that the surface of the base has the same toughness as the inside of the base. As it becomes like this,
The disappearance of the denitrification layer and bore significantly improves the adhesion strength of the hard layer to the substrate surface, and as a result, when used as a cutting tool or wear-resistant tool, the occurrence of chipping and peeling is significantly suppressed. As a result, they have found that it exhibits excellent wear resistance and can ensure an extremely long service life.

This invention was made based on the above knowledge, and the substrate surface of Si3N4-based ceramics or Sialon-based ceramics is coated with TiC* TsN +T1
CN p TtCO# TtCNO# N2 having a pressure of 10 Kg/cm2 or more is applied to a surface-coated ceramic tool coated with a hard layer consisting of a single layer or a multilayer of two or more of M2O3 and AgNO. By heating and pressurizing the tool by holding it at a temperature of 1100 to 1650°C for 5 to 60 minutes in an atmosphere, it suppresses the occurrence of chipping and peeling on the tool surface and provides excellent wear resistance. It is unique in that it extends the life of the tool by making the most of it.

Next, the reason why the heating and pressurizing treatment conditions are limited as described above in the method of the present invention will be explained.

(a) Atmospheric pressure If the atmospheric pressure is less than 10 kg/cm2, N in the atmosphere
Diffusion to the surface of the substrate through the hard layer of No. 2 is slow.

It takes an extremely long time to eliminate the denitrification layer and bore,
Since it is not practical, the pressure was reduced to 100Kg/cm2.
The above was determined. In addition, with the existing heating and pressurizing equipment, 200
Pressurization up to 0 kg/cm2 is possible.

(b) Heating temperature When the temperature is less than 1100°C, the diffusion of N2 in the atmosphere through the hard layer is slow, as in the case of atmospheric pressure;
On the other hand, if the temperature exceeds 1,650°C, N2 diffusion occurs too actively, causing alteration and coarsening of the hard layer, which in turn leads to poor wear resistance. It was set as ℃.

(c) Holding time If the holding time is less than 5 minutes, the desired N2 diffusion cannot be achieved satisfactorily even if high-temperature heating is performed, whereas a holding time of 60 minutes is sufficient under any conditions. 5 to 60 hours since you can get the results you want.
It was set as 1 minute.

〔Example〕

Next, the method of this invention will be specifically explained using actual examples.

Actual example 1 Si3N4 powder: 96.5% as a ceramic substrate
, MgO powder: 3%, S 102 powder: 0.5%, by hot pressing at a temperature of 1750°C for 1 hour in an N2 atmosphere of 1 atm. S i 3N 4 based ceramic cutting tool and S i 3N 4 powder Songnia 6%, A/203 powder: 5
%, Y2O3 powder: 3%, TiN powder: 15%, AJ
A green compact formed from a mixed powder having a blend composition of 1% N powder (the above weight %, below % indicates weight 1%) was heated to 1,800°C in a N2 atmosphere for 2 hours. β-sialon-based ceramic cutting tools manufactured by normal sintering under time-holding conditions were prepared, and the compositions shown in Table 1 and Methods 1 to 8 of the present invention and comparative methods 1 to 4 were carried out by forming a hard layer having an average layer thickness and then subjecting it to heat and pressure treatment under the same conditions shown in Table 1.

Comparative method 1 shows the case where the heating and pressure treatment corresponding to the conventional manufacturing method is not performed, and comparative methods 2 to 4 show the case where at least one of the heating and pressing treatment conditions (see Table 1) is applied. Conditions marked with a square mark) are outside the scope of this invention.

Next, J I
Used as a cutting indexable tip with the shape of S-5NP432. Work material: Fe12 round bar.

Cutting speed: 350 m/min.

Feed: 0.358/rev, Depth of cut: 2m.

Dry continuous high-speed cutting test of cast iron under the following conditions, and rigid material: SNCM-8 square material - Cutting speed: 150 mm/cm.

Feed: 0.25W/rev.

Depth of cut: 1.5m Cutting time: Ilam.

In the former dry continuous high-speed cutting test of cast iron, the flank wear width of the cutting edge was 0.
．． Wear resistance was evaluated by measuring the cutting time up to 3■, and in the dry interrupted cutting test of the latter steel, 1
Fracture resistance was evaluated by measuring the number of fractures among the number of 0 test cutting edges. The results of these measurements are shown in Table 1.

Example 2 A β-sialon-based ceramic wear-resistant tool manufactured under the same conditions as in Example 1 was prepared, except that the shape was a plug for draw pliers having a diameter of 20 ssφ as the ceramic base, and the surface of this tool (; A hard layer consisting of a lower layer of TiN with an average layer thickness of 0.5 μm and an upper layer of T1CN with an average layer thickness of 2 μm is coated using a chemical vapor deposition method, and then a pressure crab 200 is applied to this.
The method of the present invention was carried out by heating and pressurizing and rolling under the conditions of Ky/d, temperature = 1300°C, and holding time = 30 minutes.

Next, a plug as a surface-coated ceramic wear-resistant tool manufactured by the method of the present invention and a plug manufactured under the same conditions except that the heating and pressure treatment described above was not performed.

Work material: 845C1 Rolling reduction rate: 30%, Thickness: 3 fins.

Pulling speed: 15m/1lil.

When the plug was used for drawing steel pipe under the following conditions and the drawing surface of the plug was rough due to wear, the length of the processed pipe until the end of its service life was measured, and the former plug manufactured by the method of the present invention showed a length of 1400 m. On the other hand, the latter plug, which was not subjected to heat and pressure treatment, reached the end of its service life after a processing length of 450 m.

〔Effect of the invention〕

From the results shown in Table 1 of Example 1, the cutting indexable tips as surface-coated ceramic cutting tools manufactured by methods 1 to 8 of the present invention, respectively, were manufactured by comparative method 1 without heat treatment. Compared to conventional cutting indexable inserts, this insert not only exhibits superior wear resistance, but also eliminates chipping and breakage on the cutting edge.
It is clear that it also has excellent fracture resistance.

On the other hand, as seen in Comparative Examples 2 to 4, if any of the heating and pressure treatment conditions deviates from the scope of the present invention, the desired excellent wear resistance and chipping resistance cannot be achieved. It is something.

In addition, as seen in Example 2, the plug as a surface-coated ceramic wear-resistant tool that has been subjected to heat and pressure treatment according to the method of the present invention has a significantly longer service life than the plug that does not have this process. It is clear that this will happen.

As described above, according to the method of the present invention, it is possible to produce a surface-coated ceramic tool in which there is no denitrification layer on the surface of the substrate and the hard layer has good adhesion strength to the substrate surface. This is put to practical use as cutting tools and wear-resistant tools (
When used for two or more times, it exhibits excellent abrasion resistance without chipping or peeling, and exhibits excellent performance over an extremely long period of time, resulting in industrially useful effects.

Claims (1)

[Claims] The substrate surface of silicon nitride-based ceramics or sialon-based ceramics is coated with Ti carbide, nitride, carbonitride,
100 kg/ A method for manufacturing a surface-coated ceramic tool, characterized by subjecting it to a heating and pressure treatment at a temperature of 1100 to 1650° C. for 5 to 60 minutes in a nitrogen atmosphere having a pressure of cm^2 or more.