JPH04135105A - Coated hard alloy tool - Google Patents

Abstract

PURPOSE:To attain increase of strength in a base body and reduction of a decarbonized layer, increase edge point strength, and improve pitching resistance and wearing resistance by specifying a coating thickness of a de-beta layer and a film innermost layer TiC. CONSTITUTION:A cemented carbide alloy, consisting of one kind or more of carbide, nitride and carbon nitride in 4a, 5a, 6a groups and one kind or more of Fe group and Cr group of the periodic table, serves as a base body to produce a 5 to 50 micron debeta layer on surfaces of the base body, and the base body is coated with 0.2 to 1 micron TiC as the innermost layer, 1.0 to 5 micron TiN as the second layer, 5 to 15 micron one or two kinds or more of TiC, TiCN or Al2O3 as the third layer and 1.0 to 5 micron TiN as the outermost layer. To produce the debeta layer of the base body surface, 0.05 to 0.5% TiN by conversion to N quantity or 0.1 to 1.0% TaN by conversion to N quantity is contained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to coatings of cemented carbide, particularly to improving the adhesion between a substrate and a coating.

[Conventional technology] Conventionally, cemented carbide has T i C, T j, N, A
], ZOS, etc., many products have been put into practical use, but the trend has been to improve their wear resistance.

However, as the applications of coated tools expand, the areas in which they are used also expand, and tools that can be used for rough machining, heavy interrupted cutting, etc. are required.

In addition, high-speed cutting is progressing, and medium or lightly interrupted cutting is performed at a speed close to finishing, so there is a need for longer life in terms of chemical stability.

However, since cemented carbide is basically a brittle material, it is prone to chipping and chipping due to impact, etc. Also, since the coating is not continuously cut, it is likely to peel off if the adhesion between the coatings is not sufficient.

[Problem that the invention seeks to solve]

Next, regarding the cemented carbide base, conventional M20 to M3
By adding nitrides such as TiN to an alloy equivalent to 0, a so-called deveta layer is created near the surface (approximately 5 to 50 microns from the base surface is the WC-Co phase), and cracks propagating from the film are prevented. Methods have been taken to inhibit this and increase the strength of the substrate-film. (Unexamined Japanese Patent Publication No. 54-87119) However, in this method: 1) Since a large amount of nitride is added to the substrate, sinterability deteriorates and defects are likely to occur.

2) The innermost layer of the film is a Ti compound such as TiC or TiN, and the bonding parts are not made of the same type of material, so the adhesion strength is weak.
Particularly in the case of TiC, there are drawbacks such as a tendency to generate a decarburized phase due to the movement of carbon.

Therefore, in JP-A-54-87119, measures are taken such as containing about 0.01 to 0.5% of free carbon in the substrate.

Next, there are many factors that affect the film, and it is possible to give it features depending on the application.

Therefore, by taking advantage of the characteristics of chemical vapor deposition (CVD), it is necessary to apply a film that prioritizes strength.In other words, in order to reduce the decarburized layer between the substrate and the film, it is necessary to select a film quality that inhibits the movement of carbon, and to - It is effective to make one layer thinner to ensure adhesion between films.

[Means to solve problems]

Therefore, the present inventors assumed a de-beta phase in the JIS M layered hard alloy, and as a result of various studies on preventing the formation of a brittle decarburized layer, we found that when a TiN film is combined with the CVD method, the carbon that causes the decarburized layer is removed. However, since the nitride is coated on the substrate, the adhesion between the substrate and the coating is poor, making it unsuitable for practical use. However, by combining TiC in the innermost layer to an extent that improves adhesion, a balance between the two can be achieved.
Improved strength due to the de-beta phase, it is possible to reduce the decarburized layer without compromising adhesion, and overall it is a coated tool with sufficient strength against cracking, tubbing and peeling of the coating due to the impact of heavy interrupted cutting. was gotten.

[Effect]

As described above, the present invention applies to items 4a' and 5a of the periodic table.

One or more of group 6a carbides, nitrides, and carbonitrides, and Fe
The base material is a super-hard alloy made of one or more members of the Cr group and the Cr group,
producing a deveta phase of 5 to 50 microns on the surface of the substrate;
On the substrate 1) TiC0.2-1 micron as the innermost layer 2) TiN1.0-5 micron as the second layer 3) Ti as the third layer
One or more of C, T1CN or AL2035
~15 microns 4) A coated cemented carbide tool characterized by having a TiN coating of 1.0 to 5 microns as the outermost layer.

The deveta phase and coating of the coated tool according to the present invention are limited for the following reasons.

1) Debeta phase 5 to 50 microns If the thickness of the deveta phase is less than 5 microns, sufficient strength cannot be imparted, and if it exceeds 50 microns, wear resistance (welding resistance) will deteriorate. It was set to 50 microns.

In addition, in order to generate the de-beta phase, a method is generally used in which nitride is added and the solute transfer is applied to the denitrification phenomenon, but in the present invention, the atmosphere adjustment during sintering is By adjusting the nitrogen atmosphere and the carburizing atmosphere, it is possible to generate the metal while keeping the amount of bonded metal approximately the same.

In addition, although TiN can be used satisfactorily, other nitrides can also be used.
For example, 5a group nitrides and carbonitrides such as Ta and Nb can be sufficiently produced by adjusting the amount of addition and nitrogen atmosphere.

2) Innermost layer TiC0.2-1 micron substrate WC-Co
In order to maintain adhesion with the alloy, it is necessary to have a thickness of 0.2 microns or more, and if it exceeds 1 micron, a decarburized layer is likely to occur at the interface, so it is set to 0.2 to 1 micron.

3) Second layer TiN1. O~5 micron substrate WC-Co
In order to inhibit decarbonization from the alloy, it is necessary to have a thickness of 1 micron or more, and if it exceeds 5 microns, it will not provide sufficient wear resistance, so it is set to 1.0 to 5 microns.

3) Third layer TiC, T1CN or HaA 1205 (0
One or more types of 5 to 15 microns In order to have sufficient abrasion resistance, 5 microns or more is required, and if the thickness exceeds 15 microns, the overall thickness of the film becomes thick and peeling easily occurs, so 5 to 15 microns is required. Micron.

4) Outermost layer TiN1. O ~ 5 microns In order to have sufficient welding resistance, 1.0 micron or more is required, and if it exceeds 5 microns, peeling tends to occur, so 1.
The diameter was 0 to 5 microns.

The present invention will be specifically explained below.

[Example 1] Commercially available WC powder (average particle size 5.0 μm), TiC powder (average particle size 1.0 μm), TiN powder (average particle size 1°0 μm)
), using TaC powder (1,5 μm) and Co powder as binder phase, JIS used for turning substrate in -a
Equivalent to M20 (composition 86WC=2TiC-5TaC-
7Co-0,2TiN). These powders were blended while varying the amount of N, and after mixing, the resulting bond was press-molded and sintered for 1 hour at 1400°C in a vacuum with a methane and nitrogen atmosphere adjusted, and then made into SNMA43.
Processed into 2 shapes.

The results of polishing this chip and measuring the thickness of the de-beta layer are shown in the table below. It was implemented as TiN.

Table 1 Table 2 [Example 2] Powder similar to Example 1 and TaN powder (1.5 μm) Nb
Using N powder (1.5 μm), the thickness of the deveta layer was changed by changing the degree of vacuum and holding time during sintering below the liquid phase generation temperature, and in the same manner as in Example 1. It was measured. Table 2 shows the thickness of the deveta layer.

Even with nitrides such as TaN and NbN, a sufficiently thick deveta layer can be obtained by adjusting the amount added and the atmosphere.

[Example 3] SNM was made using the cemented carbide equivalent to JIS M30 used in Example 1 and sample number 3 (produces a deveta phase of 25 microns).
A432 was produced. Various surface treatments were performed on the surface depending on the purpose. TiC was installed in a CVD reactor,
TiCl was heated to 1000°C while flowing H and gas.
42% CH, 44% CH, and the remainder H2 at a flow rate of 7
Supplied under the condition of 1/min pressure of 40 mmHg.
The reaction was carried out for 2 to 3 hours to form a TiC covering layer of 0.2 to 5 microns on the substrate. Similarly, in the case of TiN, change the gas system to 22% N. The reaction was carried out for 2 to 3 hours to form a TiN coating layer of 0.2 to 5 microns on the substrate. Table 1 shows the film quality and thickness of the materials produced.

Results in Table 1: ◇: Caused by peeling ○: Chizubing occurred ○: Normal wear In order to confirm the fracture resistance and peelability of the chip, a cutting test was conducted by cutting one piece with a milling tool.

Holder Double negative type Single insert SNMA432 Work material SCM-440H345 Cutting speed 200 m/min Feed 0.
3mm/blade depth of cut: approx. 5mm Lifespan judgment Observation of damage after 5 minutes of cutting The state of damage after cutting can be classified into three types: peeling, chipping, and normal wear.The results are also listed in Table 3. do.

As shown in Table 3, peeling occurred in the innermost TiN layer even if it was thin to some extent, but in the case of the TiC layer, there was no peeling and normal wear was observed. However, as the innermost TiC layer becomes thicker, more decarburized layers are formed and the chipping resistance tends to deteriorate.

[Example 4] The cemented carbide equivalent to JIS M30 used in Example 1 and sample number 5 (produced a deveta phase of 35 microns) was used for SNM.
A432 was produced. Various surface treatments were performed on the surface depending on the purpose. The layer structure is shown in Table 4.

Table 4: Layer structure of 34 is TiC-TiN-1, 5μAl2O
,-2,0TiN--1,5μ Al2O3”2.0μ
The conditions for the TiN cutting test were intermittent cutting of a structural steel round bar. In interrupted cutting, the load is applied shockingly, and chipping resistance, which is important for cutting performance, has been evaluated as N.

Cutting speed 200 m/min feed 0
．． 2 mm/rev Depth of cut 3.0 mm Cutting time 2 m1n As a result, the tip of the present invention exhibited normal wear and no chipping due to the multilayered coating. Furthermore, the cutting process was continued under the same cutting conditions to compare wear resistance. At a cutting time of 10 minutes, there was no significant difference between the chips, but after 30 minutes of cutting, the excessive wear on the flank surface showed normal wear, confirming the effect of multilayering.

〔Effect of the invention〕

The coated cemented carbide tool of the present invention has a deveta layer and an innermost coating layer T.
By specifying iC, we have achieved increased strength in the base and reduced decarburized layer, increased cutting edge strength, and improved chipping resistance and wear resistance, making coated tools more applicable to interrupted fields. It is a tool that has expanded its range.

Claims (6)

[Claims] 1. Carbides and nitrides of groups 4a, 5a, and 6a of the periodic table,
A superhard alloy consisting of one or more carbonitrides and one or more of Fe group and Cr group is used as a base, a deveta phase of 5 to 50 microns is generated on the surface of the base, and 1) Inner layer: TiC 0.2-1 micron 2) Second layer: TiN 1.0-5 micron 3) Third layer: TiC, TiCN or Al_2O_
4) A coated cemented carbide tool characterized by being coated with Ti as an outermost layer with a thickness of 1.0 to 5 microns. 2. A hard metal tool according to claim 1, characterized in that a nitride is contained in order to generate a deveta phase directly on the surface of the substrate. 3. In claim 2, in order to generate a deveta phase on the surface of the substrate, TiN is 0.0 in terms of N amount.
A cemented carbide tool characterized by containing 5 to 0.5%. 4. In claim 2, in order to generate a deveta phase on the surface of the substrate, TaN is converted into an amount of N of 0.1
A superhard alloy tool characterized by containing ~1.0%. 5. 2. A cemented carbide tool according to claim 1, wherein the deveta phase on the surface of the base has a bond metal that is almost similar in composition to that of the base. 6. In claim 1, the third layer coating is A.
A cemented carbide tool characterized by being composed of multiple layers of l_2O_3.