JPS6220863A - Production of surface coated high speed steel member for cutting tool - Google Patents

Abstract

PURPOSE:To improve the adhesiveness of a coating layer and to extend the life of a tool by preliminarily coating the film of the carbide, nitride, carbonitride, carbonitrooxide or carbonate of Ti on the surface of a high speed steel for a cutting tool then forming a regular coating layer thereon. CONSTITUTION:The cutting tool made of the high speed steel is put into a vacuum vessel and after the tool is heated to 560-650 deg.C, gas such as C2H2, N2 or CO is introduced into the vessel to form the preliminary film of the hard layer consisting of TiC, TiN, TiNC, TiCNO, TiCO, etc., by 2-10min of a physical vapor deposition method. In succession thereof, the regular film consisting of the Ti compd.of the same quality is formed thereon after or in the mid-way of the temp decrease down to 450-500 deg.C to form the above- mentioned hard Ti compd. film to 0.5-10mum thickness in total. Since the hard film has the high adhesiveness to the high speed steel, the film does not exfoliate during use and contributes to the extension of the service life of the high speed steel tool.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a surface-coated high-speed steel member for a cutting tool, in which a hard coating layer is formed on the surface, and in particular,
A hard titanium compound coating layer is formed on the surface. The present invention relates to a method for producing surface-coated high-speed steel members for cutting tools with excellent durability using a one-reactivity physical vapor deposition method.

[Conventional technology]

Conventionally, high-speed steel (hereinafter referred to as HSS) has been widely used as a material for cutting tools because it has high hardness and excellent toughness that can withstand high-speed cutting. Providing a hard coating layer made of a titanium compound improves welding resistance, seizure resistance, and wear resistance, and dramatically extends tool life. For example, coating chips in which the surface of the indexable chip is coated with a titanium carbide or titanium nitride layer of about 2 μm using a reactive physical vapor deposition method are widely used.

A high speed steel member for a cutting tool having a surface coating layer of titanium carbide or titanium nitride is first coated with a pressure crab of 1O"" to 10-3To by a one-reactive physical vapor deposition method.
After heating the substrate to a temperature of 400-450°C in a vacuum atmosphere of rr, the substrate is optionally subjected to ion etching with argon at a pressure crab of 10-' to 10-2 Torr, followed by subsequent maintenance of this temperature and pressure. However, by causing a coating reaction with titanium carbide or titanium nitride, in other words, metallic titanium evaporated by an electron beam or the like and acetylene or nitrogen gas supplied into the coating furnace are ionized to form f1+ and C+ or the furnace, and these It is manufactured by electrically attracting ions onto a negatively charged substrate to form a coating made of titanium carbide or titanium nitride, respectively, on the surface of the substrate.

[Problem that the invention seeks to solve]

However, if a titanium compound such as titanium carbide or titanium nitride is coated on a high speed steel substrate at 400 to 450°C as described above.

Direct bonding between the coating layer formed by these titanium compounds and the HSS substrate and diffusion of the coating layer into the substrate hardly occur, so the coating layer has poor adhesion.
The thus obtained surface-coated high-speed steel cutting tool has the disadvantage that it tends to peel off during cutting, 1 and therefore has a short tool life.

[Findings based on research]

Therefore, the inventors of the present invention have conducted various studies to solve such problems.

(1) Titanium carbide 1 Titanium nitride, titanium carbonitride.

Titanium carbonitride oxide and titanium carbonate (hereinafter referred to as TiC, TiN, T1CN, TiCN0, respectively)
When coating a high speed steel substrate with titanium carbon, nitride, and oxide (denoted as titanium carbon, nitride, and titanium oxide for convenience) by one-reactive physical vapor deposition, the temperature of the substrate is higher than the tempering temperature of the high speed steel. , the direct reaction between the coating layer and the substrate accompanying the transformation of the high speed steel and the diffusion of the coating layer into the substrate are promoted, and the adhesion between the two is improved.

(2) The tempering temperature of high speed steel is generally 530 to 650.
Because it is as low as ℃, it may cause the substrate temperature to rise extremely,
Alternatively, if the elevated temperature is maintained for a long time, the high speed steel will become dull and soften, so the temperature should be 560 to 650℃.
A suitable coating time is 2 to 10 minutes.

(3) Although the above coating does not provide a coating layer with sufficient thickness, 1 this is used as a preliminary coating, and then the main coating is applied to the preliminary coating layer formed by this preliminary coating to a total thickness of 0. .5-1
(4) If this coating layer with a thickness of 0 μm is formed, a coating layer with excellent adhesion as a whole can be obtained, and as a result, a surface-coated high speed steel member for a cutting tool with a dramatically extended tool life can be obtained; Even if the substrate temperature during the main coating applied after the preliminary coating is slightly higher than before, there is no adverse effect on the HSS, and a main coating layer that is compatible with the preliminary coating layer can be obtained.
500℃ is suitable.

(5) It has been found that even when the main coating is started after the preliminary coating is completed while the temperature is lowered from the temperature of the preliminary coating, a coating layer excellent in vu adhesion as described above can be obtained.

[Means for solving problems]

This invention was invented based on the above knowledge, and utilizes a reactive physical vapor deposition method to coat cutting tools with any one of titanium's coating components selected from carbon, nitrate, and oxide. A method for producing a surface-coated high-speed steel member for a cutting tool, in which a coating layer made of the coating component is formed on the surface by coating a high-speed steel substrate for use,
After heating the substrate in vacuum to a temperature of 560 to 650°C, immediately pre-coat the coating component on the substrate at this temperature for 2 to 10 minutes to form a preliminary coating layer made of the coating component on the surface of the substrate. The thus precoated substrate was then heated to a temperature of 450°C.
After the temperature has been lowered to ~500°C, or during and after the temperature drop, the same coating component as that used to form the pre-coating layer is main-coated on the pre-coating layer to form the pre-coating layer. A main coating layer made of the coating component is formed on the surface of the coating layer, and then the main coating layer is formed on the surface of the coating layer.

It consists of the preliminary coating layer and the main coating layer. Overall thickness 10
The present invention provides a method for manufacturing the surface-coated high-speed steel member for a cutting tool, characterized in that the substrate is coated with a coating layer of 5 to 10 μm.

Next, the reason why the pre-coating temperature, pre-coating time, main coating temperature and coating layer thickness are each limited as described above in this invention will be described.

(a) Pre-coating temperature If the pre-coating temperature is less than 5°C, the direct reaction between the pre-coating layer and the substrate and the diffusion of the coating layer into the substrate will not be achieved sufficiently, so that the desired adhesion between the two will not be achieved. On the other hand, if the temperature exceeds 650°C, the HSS becomes dull and softens during preliminary coating for 2 to 10 minutes.

The pre-coating temperature was set at 560-650°C.

(b) Pre-coating time A pre-coating time of less than 2 minutes prevents direct reaction of the pre-coating layer with the substrate and diffusion of the coating layer into the substrate, even if the substrate is raised to the pre-coating temperature mentioned above. Because the adhesion does not proceed sufficiently, the desired adhesion cannot be obtained between the two, and on the other hand, if the adhesion exceeds 10 minutes, the adhesive becomes dull and softens even if the substrate is kept at the above temperature. The time was set at 2 to 10 minutes.

(Cj Main coating temperature Generally speaking, the smaller the difference between the substrate temperature during two coatings and that during pre-coating, the better the pre-coating layer and main coating layer will fit together, resulting in a highly durable coating layer. In addition, even if the coating temperature is increased slightly, ie, by 50°C, compared to the conventional technology, there will be no adverse effect on the high speed steel.

Instead of the conventional coating temperature of 400-450°C, in this invention the coating temperature is 450°C.
The temperature was set at ~500°C.

(d) Thickness of coating layer The thickness of the entire coating layer is 0. ．． If the thickness is less than 5 μm, it will not be possible to obtain a surface-coated HSS member for a cutting tool that exhibits excellent cutting performance, and if it exceeds 10 μm, no particular improvement in cutting performance will be obtained. .5~10μ
It was determined as m.

The invention is accomplished by a reactive physical vapor deposition process conventionally commonly utilized to deposit titanium carbon-nitrogen-oxide coatings on the surface of high-speed steel substrates, including the use of acetylene, nitrogen, or carbon monoxide. When a gas like this is introduced,
In a coating furnace maintained at a pressure of 10"-' to 10-2 Torr, metallic titanium is evaporated using an electron beam or the like, and these reactive components are ionized using a discharge phenomenon to produce Ti", N+, and C". , O+, etc., and these cations are deposited on the negatively charged high-speed steel substrate by electrical attraction, thereby causing carbon, nitride, and oxides of titanium to be deposited on the surface of the substrate. Form a film.

The present invention can be applied to the production of surface-coated nozzle members for various cutting tools, and can be particularly advantageously used for the production of coated tips specific to indexable tips.

〔Example〕

Next, the present invention will be explained by examples and in comparison with comparative examples.

Steel type: 5KH2 high speed steel tempering temperature = 560-580
Hardness obtained by tempering at °C: HRc
(Rockwell hardness C scale) A large number of indexable tips with a shape of T P 322 were manufactured from high speed steel having a hardness of 64, and using these tips as a base, 10
Immediately after raising the temperature of this substrate to a temperature between 560 and 600°C in a coating layer maintained at a vacuum level of -5 Torr, at this temperature, any one of carbon, nitride, and oxide of titanium is formed. is pre-coated on the surface of the substrate for 5 to 10 minutes, and then the temperature of the substrate is lowered to 450 to 500 ° C.,
Coated chips 1 to 8 of the present invention are manufactured by main coating with the same coating components as those used in the preliminary coating, and as an alternative method to the method of the present invention, in the above manufacturing method, while lowering the substrate temperature to 480 ° C. At point 1 of starting the main coating and before pre-coating in the manufacturing method, the substrate temperature:
Coated chips 9 and 10 of the present invention were respectively manufactured by a method that differed from the above manufacturing method only in that etching with argon was performed at 600° C. for 10 to 20 minutes.

Furthermore, for comparison, the coating chips 1 to 1 of the present invention
8, the manufacturing conditions are outside the scope of the present invention, and the temperature is 450 to 500°C.
By etching for 10 to 20 minutes at (
In addition to manufacturing comparative coating chips 1 and 2 (indicated by *marks indicating conditions that differed from the above), the substrate was heated to 450°C in a coating furnace maintained at a vacuum level of 0-5 Torr, and then heated with argon at the same temperature. Conventional Coating Chips 1-5 were prepared by the conventional method of etching a substrate with a carbon-nitrate oxide of titanium at that temperature.

In each of the above methods, the substrate voltage was -1.5 KV and the Ar pressure was 1 O Torr during etching, and the substrate voltage was -0.8 KV during coating.

The reaction gas used to form the coating layer of each titanium compound and the furnace pressure during coating were as shown in Table 1 below.

Table 1 For each chip thus obtained, the manufacturing method type, pre-coating temperature and time, single coating temperature, and coating layer components and thickness are shown in Table 2.

Next, the Rockwell hardness C scale (HRC) of these chips and uncoated chips was measured, and
In order to evaluate the life of these tools, a cutting test was conducted under the following conditions, and the cutting time until vB wear reached 0.3 was measured, and this was taken as the tool life.

Cutting conditions Work material: SN0M8. HB: 250, holder: P
22R-44, cutting speed: V = 60 m/mR, d -1.5m
x, f −0,1mx/rev,.

The above results are also summarized in Table 2.

〔Effect of the invention〕

From the results shown in Table 2, the tool life of conventionally coated inserts is 15 to 30 minutes;
In contrast to the case where the coating layer peeled off during cutting, with the coated chips of the present invention, the coating layer did not peel off during cutting, and the tool life was dramatically increased to 120 to 170 minutes. In Comparative Coated Chips 1 and 2, which were manufactured by a method in which the cutting time was not long or the temperature was too high, the tool life was extremely short because the HSS became dull and softened during cutting.

As is clear from the above description, according to the present invention, it is possible to obtain an industrially useful effect of obtaining a surface-coated high speed steel member for a cutting tool that has extremely excellent wear resistance and therefore has an extremely long tool life.

Claims (1)

[Claims] Using a reactive physical vapor deposition method, one coating component selected from titanium carbide, titanium nitride, titanium carbonitride, titanium carbonitride, and titanium carbonate is applied to a high-speed steel substrate for cutting tools. In the method for producing a surface-coated high-speed steel member for a cutting tool, the substrate is heated to a temperature of 560 to 650° C. in vacuum, the surface of which is coated with a coating layer made of the coating component. Immediately after raising the temperature, 2 coats of the coating component are applied to the substrate at this temperature.
Pre-coating for ~10 minutes to form a pre-coating layer made of the coating component on the surface of the substrate, and then heating the thus pre-coated substrate to a temperature of 450~
After the temperature has been lowered to 500° C., or during and after the temperature decrease, the same coating component as that used to form the pre-coating layer is main-coated on the pre-coating layer to form the pre-coating. A main coating layer made of the above-mentioned coating components is formed on the surface of the layer, whereby the total thickness of the preliminary coating layer and the main coating layer is 0.5.
A method for manufacturing a surface-coated high-speed steel member for a cutting tool, characterized in that the substrate is coated with a coating layer of ~10 μm.