JPS6326348A - Production of surface coated high-speed steel member for cutting toll or wear resistant tool - Google Patents

Abstract

PURPOSE:To obtain the titled high-speed steel member coated with a hard Ti compound having especially superior adhesion by vapor-depositing a hard coating layer on a high-speed steel substrate and slowly cooling the substrate heated to the tempering temp. of the steel or below to room temp. at a prescribed cooling rate. CONSTITUTION:A hard coating layer of one or more kinds of coating components selected among TiC, TiN and TiCN is vapor-deposited on a high- speed steel substrate for a cutting tool or a wear resistant tool by physical vapor deposition. After the end of the vapor deposition, the high-speed steel substrate heated to the tempering temp. of the steel or below by PVD is slowly cooled to room temp. at 50-100 deg.C/hr cooling rate. Thus, the adhesion of the coating layer is remarkably improved and a surface coated high-speed steel member for a cutting tool or a wear resistant tool having remarkably improved wear resistance is obtd.

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 use in cutting tools and wear-resistant tools, which has a hard coating layer formed on its surface, and particularly relates to , relates to a method for producing surface-coated high-speed steel members for cutting tools or wear-resistant tools, which have a coating layer of a hard titanium compound with excellent adhesion formed on the surface, using a physical vapor deposition method. .

[Conventional technology]

Conventionally, high-speed steel (hereinafter referred to as high-speed steel) has high hardness and excellent toughness, so it has been used in cutting tools such as indexable inserts, bits, gear hobs, taps, drills, and end mills, as well as punches, bolts, and dies. It is widely used as a material for wear-resistant tools such as
Providing a hard coating layer made of a titanium compound such as titanium carbide or titanium nitride on the surface of this high speed steel improves welding resistance, seizure resistance, and wear resistance, and dramatically extends tool life. Recently, it has become popular to provide such a coating layer on the surface of high speed steel with a thickness of 1 to 8 μm.

In order to produce such titanium carbide-cutting HSS components for tools or wear-resistant tools by reactive physical vapor deposition, for example, first the HSS substrate is placed in a reactor. pressure crab 10-5~1O-5
Tempering of high speed steel in a vacuum atmosphere of Torr 1y ff+?
After heating to a temperature below ＞℃, pressure crab 10'~10
Optionally, the substrate is subjected to ion etching with argon at Torr, followed by a coating reaction with titanium carbide or titanium nitride while maintaining this temperature and pressure, i.e. evaporated by e.g. with an electron beam in a reactor. Metallic titanium and acetylene or nitrogen gas supplied into this reactor are each positively ionized, and these positive ions are electrically attracted onto a negatively charged substrate to form titanium carbide or titanium nitride, respectively. A coating film is deposited and formed on the surface of the substrate, and then the substrate is cooled to room temperature by being left to cool or by blowing argon gas into a reactor.

[Problem that the invention seeks to solve]

However, titanium carbide, titanium nitride, and titanium carbonitride (hereinafter referred to as TiC1TiN and AiCN, respectively, and for convenience, collectively referred to as titanium carbon/nitride) in the surface-coated high-speed steel members manufactured by the above method. ) coatings have poor adhesion, so high speed steel members for cutting tools or wear-resistant tools coated with such coatings have a problem of short tool life.

[Findings based on research]

In order to solve these problems, the inventors of the present invention have conducted various researches, and as a result, have developed a coating layer made of titanium carbon/nitride coating components for use in cutting tools or durable materials using physical vapor deposition. When coating a high speed steel base for a wear tool, after the coating layer has been deposited on the base, the base, which had been heated to a temperature below the tempering temperature of the high speed steel by applying the reactive physical vapor deposition method, is brought to room temperature. It has been found that a surface-coated high speed steel member for cutting tools or wear-resistant tools with excellent adhesion can be obtained by cooling at a cooling rate of 50 to 100°C per hour.

This result is because the thermal expansion coefficient of HSS is generally much larger than that of titanium carbon/nitride, so if the substrate after coating is cooled casually, that is, relatively quickly to room temperature, as in the past, However, as mentioned above, the coating layer cannot sufficiently follow the sudden contraction of the HSS base, resulting in peeling or misalignment between the base and the coating layer, or distortion remaining in the coating layer. When the substrate is cooled relatively slowly,
The nois base gradually contracts, and the compressive force generated at the interface with the coating layer due to the contraction acts gently on the coating layer, thereby making it difficult for the above-mentioned peeling, displacement, or distortion to occur. This is thought to be based on this.

[Failure to solve the problem]

This invention was invented based on the above knowledge, and uses physical vapor deposition to produce TiC, Tj-N and ']'
A cutting tool in which a coating layer made of the coating component is attached to the surface by coating a cutting tool or wear-resistant tool base with one or more coating components of iCN. In the method for manufacturing a surface-coated tool member for use in or wear-resistant tools, after the coating layer has been deposited on the substrate, the substrate is heated to a temperature equal to or lower than the tool tempering temperature by applying the physical vapor deposition method. A method for producing a surface-coated chair member for cutting tools or wear-resistant tools, characterized in that the substrate is cooled to room temperature at a cooling rate of 50 to 100° C. per hour;
This is related to.

[Detailed description of the invention]

(1) ÷÷←→Physical vapor deposition method The physical vapor deposition method used in this invention is applied to, for example, TiN.
To explain the deposition formation of a film as an example, as shown in the schematic diagram in FIG. ,... After heating the substrate to a temperature below the tempering temperature of the chair, the substrate is optionally subjected to ion etching with argon at a pressure of 0-' to 10-2 Torr, and then nitrogen gas 2 is added instead of the argon. Introduced into the reactor 1 to maintain the atmospheric pressure and temperature within the reactor 1 at the above-mentioned pressure and temperature, and provided between the base 3 and the water-cooled copper crucible 4, which are disposed facing each other in the reactor 1. A DC voltage of several tens of volts is applied to the discharge electrode 5 to generate a discharge between the metal titanium 6 held in the crucible 4 and the discharge electrode 5, and the plasma of the nitrogen gas 2 is discharged. while forming the metal titanium 6 between the electrode 5 and the crucible 4, irradiating the metal titanium 6 with an electron beam 7 to melt and evaporate it,
The evaporated titanium is passed through the plasma and ionized into positive ions, and then deposited on the base 3 which is maintained at a negative potential of 0 to 1,500 volts, and the nitrogen ionized positively by the discharge is also deposited on the base 3.
A TiN film generated by the reaction between these titanium ions and nitrogen ions is deposited on the surface of the base 30, and then the base 3, which has been heated to a temperature below the high speed steel tempering temperature, is allowed to cool or is heated externally. By means 8,
Cool to room temperature 1 at a predetermined cooling rate.

(2) Cooling rate of the substrate After forming the titanium carbon/nitride coating layer, the substrate, which was kept at a temperature below the high speed steel tempering temperature, was cooled to 100°C/hr.
If the cooling rate exceeds 50°C/hr, it will not be possible to obtain a surface coated HSS member coated with a coating layer with the desired excellent adhesion, while if the cooling rate is less than 50°C/hr, it will take time to cool the substrate. In this invention, the cooling rate of the substrate is set to 50-b. When the thickness of the coating layer is 2 to 8 μm, and the TiC and TiN coatings formed on the HSS substrate are investigated by X-ray diffraction analysis, it is found that if the cooling rate of the substrate is too fast, that is, the cooling rate If the temperature exceeds 100℃/hr, the (220)
The d value on the surface was ±004 with respect to the value of A, STM card, while the cooling rate: 50-100℃
/hr for cooling the substrate, the d value is ±0.
03 or less, and these results indicate that the coating layer obtained by the present invention causes less distortion than the conventional coating layer.

〔Example〕

Next, the present invention will be explained in comparison with a comparative example, taking as an example the production of a cutting tool coated with a titanium carbon/nitride coating layer.

Example 1 As shown in FIG. 1, a reactor 1, a water-cooled copper crucible 4,
Using a vapor deposition apparatus equipped with a discharge electrode 5 and an electric heater 8, and using titanium 6, a reaction gas 2, and a substrate 3,
m3, PA 20° right 1 line, lead angle 2° 23', Djf3
．． 5. Outer diameter: 80mm x length: 150u x inner diameter: 31.
A 5KH55 hob with the shape and dimensions of '75M was used, and the reaction conditions were: furnace temperature: 500°C, furnace pressure: nitrogen or acetylene, reaction gas flow rate: 2507/mia, and In order to prevent the substrate held at 500° C. from being rapidly cooled after the TiN coating and TiC coating with the thickness shown in Table 1 are respectively deposited on the hob surface by adopting a substrate potential knee of 100 volts. The surface-coated hobs 1 to 6 of the present invention were prepared by gradually cooling the substrate to room temperature (25° C.) at the cooling rate shown in Table 1 while supplying heat from the outside of the reactor with an electric heater 8. A comparative surface-coated hob was manufactured by allowing the substrate held at 500° C. to cool and increasing its cooling rate as shown in Table 1. 1 to 6 were produced respectively.

Next, in order to examine the wear resistance of these surface-coated hobs, the following materials were used: Work material: JTS 80M3 round bar (Hardness: HRC9-13) Fabricated gear: Number of teeth: 21, Dimensions: Outer diameter 70mm x thickness 20B
× Inner diameter 30 mm Table 1 Cutting speed: 160 r, p, m, (40 n/m1
u) Conducted an intermittent cutting test under the following conditions: feed: 2x, /'w-rev, cutting direction: climb cut, and measured the third maximum wear width on the hob surface after cutting 12.6 m. do,
The results are shown in Table 1.

Example 2 Steel type: 5KH2 high speed steel tempering temperature: 560-580
Obtained by tempering at °C, hardness: I-
Shape from HSS with TRC64: 'T'PP32
A large number of indexable chips No. 2 were manufactured, and using these chips as bases, the same coating conditions as in Example 1 were adopted, and TiN, TiC and 'J:'iC'N (however, , C/N ratio=4/6,
In this case, a mixed gas of acetylene and nitrogen is used as the reaction gas) After depositing and forming a coating layer on the chip surface, the chip kept at 500°C is cooled at the cooling rate shown in Table 2. By doing so, surface-coated chips 1 to 9 of the present invention and comparison surface-coated chips 1 to 9 were each made into confectionery products.

Next, in order to investigate the wear resistance of these surface-coated tips, a cutting test was conducted under the following conditions, and the vB wear was 0.
The cutting time until reaching 3 myn is the tool life.
The time was measured and the results are shown in Table 2.

Cutting conditions Work material: SN0M8, HB: 250.

Holder: P 22R-44, Cutting speed: V=60 m/mia, d=1.5M, f
= 0.1 mm/rev.

〔Effect of the invention〕

From the results shown in Table 1, when comparing the surface-coated hob of the present invention and the comparative surface-coated hob, which are made of the same material and thickness, the third maximum wear width on the hob surface after cutting 12.6 m is It was found that the surface-coated hob of the present invention was significantly smaller, and the coating layer peeled off in the comparison surface-coated hobs 3 and 6 during cutting and immediately after the start of cutting, respectively, and from the results shown in Table 2, it was found that the Comparing the surface-coated chips of the present invention and the comparative surface-coated chips, the surface-coated chips of the present invention had a significantly longer T tool life than the comparative surface-coated chips, and the comparative surface-coated chips 6 and 9 had a coating layer that formed immediately after the start of cutting. According to the results of Examples 1 and 2, the hobs and indexable tips manufactured according to the present invention have extremely excellent wear resistance. Recognize.

As is clear from the above description, according to the present invention, it is possible to obtain a surface-coated HSS member for cutting tools or wear-resistant tools with significantly improved adhesion and therefore significantly improved wear resistance, resulting in a tool life span. The industrially useful effect of providing these surface-coated high speed steel members having a significantly long length is obtained.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an outline of the apparatus used in carrying out the method of the present invention. In the figure, l...reactor,
2... Reactive gas, 3... Substrate,
4... Crucible, 5... Electrode for discharge, 6.
...metallic titanium, 7...electron beam, 8...
Electric heater.

Claims (1)

[Claims] By coating a high-speed steel substrate for cutting tools or wear-resistant tools with one or more coating components of titanium carbide, titanium nitride, and titanium carbonitride using a physical vapor deposition method. In the method for manufacturing a surface-coated high-speed steel member for a cutting tool or a wear-resistant tool, in which a coating layer made of the coating component is attached to the surface, after the vapor deposition of the coating layer on the substrate is completed, The substrate, which had been heated to a temperature below the high-speed steel tempering temperature by applying a physical vapor deposition method, was heated at 50 to 100°C per hour.
A method for manufacturing a surface-coated high-speed steel member for a cutting tool or a wear-resistant tool, characterized in that the surface-coated high-speed steel member for a cutting tool or a wear-resistant tool is cooled to room temperature at a cooling rate of .