JPH07157862A - Wear resistant and welding resistant hard film-coated tool and production thereof - Google Patents

Abstract

PURPOSE:To impart excellent wear resistance and welding resistance to a tool and prolong its cutting service life by forming a film by an arc discharge type ion plating method and thereafter removing away macrograins projected to the coated surface. CONSTITUTION:On the surface of a tool substrate, the film of multicomponental metal oxide, metal nitride or metal carbon nitride contg. two or more kinds of metals is formed by an arc disharge type ion plating method. After that, macrograins projected to the surface of the formed film are removed away, and a hard film tool having craters of 0.2 to 2mum depth is produced. The removal of macrograins projected to the surface of the film after the ion plating and stuck is executed preferably by barrel polishing, blast polishing, lapping treatment, buff polishing or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard coating tool having excellent wear resistance and welding resistance, and a method for producing the same.

[0002]

2. Description of the Related Art When manufacturing high-speed tool steel, cemented carbide tool steel, etc., nitriding Ti, etc. on the surface of the tool base material in order to improve performance such as wear resistance. It has been practiced to form an abrasion resistant film made of a substance or a carbide. Conventionally, the CVD method (chemical vapor deposition method) and the PVD method (physical vapor deposition method) have been known as methods for forming the above abrasion-resistant film. However, in the former method, the base material is exposed to high temperatures, which may cause thermal deterioration of the base material.Therefore, in the case of tools in which the characteristics of the base material are also important, the latter method is preferred. Ti using the ion plating method, etc., which can be coated under relatively low temperature conditions
N film is commonly used.

The TiN film has better heat resistance than the TiC film, and crater wear on the tool rake surface due to working heat and frictional heat during cutting is suppressed. However TiN
Since the coating has a lower hardness than the TiC coating, it is vulnerable to flank wear generated on the flank contacting the work material, and the TiC coating exhibits higher durability against flank wear.

Therefore, as a film excellent in both heat resistance and hardness, P such as an ion plating method or a sputtering method is used.
TiAlN, TiAlC or TiAlCN by VD method
And the like have been proposed [JP-A-62-56565,
JP-A-2-194159, Journal Vacuum Society Technology (J. Vac.Sci.Technol.) A 4th
(6), 1986, p. 2717, J. of Solid State Chem.
istry, 70, 1987, pp. 318-322, etc.].

As a method for further improving the wear resistance of the tool, the present inventors have found that (V _x Ti _1-x ) (N _y C _1-y ) on the surface of the substrate, but 0.25 ≦ x ≦ 0.75 0.6 ≦ y A wear-resistant coating having a chemical composition of ≦ 1 and a thickness of 0.8 to 10 μm was formed by an arc discharge method using a cathode as an evaporation source under a vacuum condition of 1 × 10 ^{−3 to} 5 × 10 ⁻² Torr. A method of forming was developed and a patent application was completed (Japanese Patent Laid-Open No. 221057/1992).

In order to form these hard coatings, a crucible type ion plating method or a sputtering method,
Furthermore, although an ion plating method by an arc discharge method using a cathode as an evaporation source is adopted, these methods have the following problems.

(1) In the case of crucible type ion plating method Since the conventional ion plating method is a method of melting and evaporating vapor-deposited metal in the crucible, there are restrictions on the installation position of the evaporation source and a complicated shape. The vapor deposition efficiency when applied to the substrate is extremely low. In addition, although it is often the case that you want to vaporize multiple metals and alloy them on the substrate surface,
Since each metal has a difference in vapor pressure, it is difficult to stably control the alloy film composition.

(2) Sputtering method The adhesion of the film obtained by this method is not always good, and the productivity when coating a substrate having a complicated shape is low. Further, as a target, Al _X Ti _1-X or (Al _X
When using Ti _1-X ) N, V _X T _1-X , (V _X T _1-X ) N, etc., the sputter rate is likely to change over time, and this change is taken into account when changing the target composition. I have to adjust. Further, since the ionization rate of sputtered particles is low and the amount of ions entering the substrate is small, it is difficult to obtain sufficient film adhesion. Moreover, the film forming speed is slow and unsuitable for mass production.

(3) In case of arc discharge type ion plating method In this method, for example, as shown in FIG.
From which a reactive gas is introduced and an arc is generated between the evaporation source 2a to which a negative voltage is applied and the positive voltage trigger 3 to form a hard film on the substrate W loaded with a negative bias voltage. That is, in carrying out the arc evaporation method, in order to enhance the adhesion between the base material and the hard film, sputter cleaning by metal bombardment is performed prior to the hard film coating to remove impurities on the surface of the base material, and thereafter. A hard film is formed by arc evaporation.
In this method, a large cleaning effect can be obtained by the metal bombardment, so that a sufficient amount of the film adhered to the substrate can be obtained. Moreover, when an Al _x Ti _1-x N film is formed by this method, Ti and Al can be used individually as cathodes which are evaporation sources, but Al _x Ti consisting of the target composition itself can be used.
_{Using 1-X} as a target makes it very easy to control the film composition. Further, in this case, the evaporation of each alloy component is performed with a large current of several tens of amperes or more, so that the composition deviation of the cathode material hardly occurs, and the ionization efficiency is high and the reactivity is high, so that the bias voltage is applied to the base material. There are many advantages in that a film having excellent adhesiveness can be easily obtained by applying. However, the biggest difficulty observed in this method is that direct discharge is adopted from the solid cathode, so that large macro particles of about 1 to 5 μm are attached to the surface of the formed film, and not only the surface roughness and gloss are inferior. When applied as a cutting tool, etc., depending on the work material and cutting conditions, the work material may be welded to the tool coated surface,
The point is that the machining accuracy decreases and the wear resistance of the tool itself also decreases.

[0010]

As described above, in the ion plating method by the arc discharge method, TiAlC is used.
A multi-component hard coating such as N can be formed efficiently and with good adhesion, but since direct arc discharge from a solid cathode is adopted, macro particles of about 1 to 5 μm adhere to the coating surface, resulting in surface roughness. It can not be said that the gloss is not good, and when it is used as an abrasive tool or a cutting tool, not only does the work material deteriorate on the macro particles protruding on the tool surface depending on the use conditions, but also the processing accuracy deteriorates, Satisfactory wear resistance may not be obtained. Further, although a crucible type ion plating method or a sputtering method can obtain a hard coating having a smooth surface, the coating forming efficiency is very low as described above.

The present invention has been made in view of such circumstances, and an object thereof is to provide good surface roughness and gloss, exhibit excellent wear resistance, and have good welding resistance and It is an object of the present invention to provide a hard coat tool and a method for producing the same, which does not cause welding of a cutting material and can be efficiently manufactured industrially.

[0012]

A wear-resistant / welding-resistant hard coating-coated tool according to the present invention, which has achieved the above object, has a multi-component metal carbide containing two or more metal elements,
It consists of metal nitride or metal charcoal / nitride coating, and macro particles do not substantially project on the surface, and it is 0.2-2 μm.
The main point is that a hard coating having a crater of the depth of 10 is formed on the surface, and such a tool has two types on the surface of the tool base material by the arc discharge type ion plating method. It can be obtained by forming a multi-component metal carbide, metal nitride or metal carbon / nitride coating containing the above metal elements and then removing macroparticles protruding on the coating surface.

[0013]

As described above, according to the present invention, a multi-component metal carbide, metal nitride or metal carbon / nitride containing two or more metal elements is used as a hard coating for improving wear resistance on the surface of a tool substrate. (Hereinafter sometimes referred to simply as carbon / nitride), in which macro particles are not substantially projected on the surface and a hard coating having craters with a depth of 0.2 to 2 μm is formed. Yes, in particular, by removing the macro particles protruding on the surface of the film, which is seen when the arc discharge method ion plating method is adopted, the welding of the work material due to the protruding macro particles is prevented and the cutting accuracy is improved. It has succeeded in extending the cutting or polishing life.

In the present invention, the kind of metal constituting the charcoal / nitride is not particularly limited, and as long as it is a carbide / nitride or a charcoal / nitride that can form a film with high hardness and high wear resistance. , Al, V, Cr, Zr, Hf, etc., can be used, but it is possible to use two kinds of metals selected from Ti, Al, and V that have a particularly excellent effect on performance. A combination, among which [Ti _X Al _(1-X) :
(0.25 ≦ χ ≦ 0.75)] and [V _y Ti
_(1-y) : (0.25 ≦ y ≦ 0.75)] is used as a carbide, a nitride, or a charcoal-nitride that gives an excellent wear-resistant coating.

[0015] These metals give each excellent wear resistance of the coating as a carbide or nitride, among others N: C = 0.6~1: 0.4~0 [ N Z C 1-Z: (0.
6 ≦ z ≦ 1)] is preferable because it gives a high hardness coating with excellent adhesion to the tool substrate.

Such a metallic carbon / nitride coating can be formed by, for example, an arc discharge type ion plating method using a cathode as an evaporation source, and more specifically, by an arc discharge using a cathode as an evaporation source. It can be obtained by ion plating two or more ionized metal components in a nitriding and / or carbonizing atmosphere such as an N ₂ atmosphere and / or a CH ₄ atmosphere. When the targets having the same composition are used, the composition of the cathode material does not deviate, so that a film having a stable composition is easily obtained. At this time, it is preferable to apply a bias voltage to the base material because the adhesion of the coating can be further enhanced.

The gas partial pressure at the time of ion plating is not particularly limited, but preferably 1 × 10 ^{−3 to} 5 × 1.
It is about 0 ^-2 Torr, and under these conditions, a hard coating that is crystalline and more excellent in wear resistance is easily obtained.

The metal charcoal / carbide coating formed by the arc discharge type ion plating method is hard and has excellent wear resistance.
For example, as shown in FIGS. 2 (A) and 3 (A) of the embodiment described later, a large number of coarse macroparticles of about 1 to 5 μm are projected, which causes welding of the work material during cutting or polishing, and It hinders the processing accuracy as an abrasive tool.

Therefore, in the present invention, substantially all of the macro particles are removed by polishing to smooth the surface. At this time, traces of removal of the above-mentioned macroparticles on the coating surface are 0.2 to 2.0 μm.
Although it remains as a shallow crater of about m (see FIGS. 2 (B) and 3 (B) below), this crater can significantly enhance the welding resistance during use without causing welding of the work material, As a result, the processing accuracy is increased. Therefore, the surface-coated tool of the present invention has a depth of 0.2 to 2.
It is characterized by the presence of many craters of 0 μm.
The coated tool of the present invention having a nitride film formed thereon is hard and has both excellent wear resistance and welding resistance. The method for removing macroparticles protruding on the coating surface after ion plating is not particularly limited, but preferred are barrel polishing, blast polishing using glass beads, lapping treatment, buff polishing, and the like. In this case, the polishing force is concentrated on the macroparticles protruding on the surface, and only the macroparticles can be removed without almost abrading the coating, which is preferable.

The preferred coating thickness after removal of macroparticles (actually not much different from that before removal) is not particularly limited, but if it is too thin, the abrasion resistance tends to be insufficient, while if it is too thick, the coating may crack due to impact force. Since it tends to enter easily, it is usually preferable to set the thickness to about 0.8 to 10 μm.

By the way, when it is put into practical use as a solid bob having a surface coating, for example, most of the hard coating on the rake face is usually removed by the step of polishing the rake face. If it is obtained, if the macro particle removal treatment after formation of the hard coating is completed in a short time of about 5 to 10 minutes, the cutting edge portion of the bob can be kept in a sharp state with R of 10 μm or less. Therefore, unlike the conventional example, it is not necessary to perform the cutting process, and as a result, it can be put to practical use with the hard coating left on the rake face, so that the wear resistance of the cutting portion is further enhanced.

[0022]

EXAMPLES Next, examples of the present invention will be shown, but the present invention is not limited by the following examples, and may be carried out with appropriate modifications within a range compatible with the gist of the preceding and following description. Of course, it is possible, and all of them are included in the technical scope of the present invention.

Example 1 Using a high speed steel equivalent to JIS SKH55 as a substrate, a solid bob (having a surface roughness of about 1 μm) of module 2.5PA 20 °, outer diameter 80 mm × length 80 mm was prepared. Hard coatings were formed on the bob surfaces by the following methods.

(1) TiCN film by crucible type ion plating (5 μm) (deposition conditions) Substrate temperature: 400 ° C. Bias voltage: −150 V Reaction gas pressure: 7 × 10 ⁻³ Torr (2) Arc discharge type ion plating (Ti, Al) N film (5 μm) by the coating method (film forming condition) Substrate temperature: 400 ° C. Bias voltage: −150 V Reaction gas pressure: 7 × 10 ⁻³ Torr (3) Film formation formed by the above (2) Barrel polishing of objects (barrel polishing conditions) Alumina barrel chips with a diameter of 2 mm and # 800WA abrasive are used, and polishing time is 10 minutes.

The surface roughness of the flank surface of the solid bob obtained in (2) above (by a stylus type roughness meter) is as shown in FIG. 2 (A) and FIG. 3 (A) (surface micrograph). That is, a large number of coarse macroparticles are projected on the surface, and a large number of protrusions of maximum 2.4 μm due to the macroparticles are present. On the other hand, the film surface obtained in (3) obtained by barrel-polishing the film obtained in (2) above has a surface as shown in FIG.
As shown in (B) (surface micrograph), most of the macroparticles on the surface are removed and most of the projections derived from the macroparticles disappear, and the removal traces have a depth of 0.2-2. 0
It appears as a crater of about μm. Further, the coating thickness before and after barrel polishing was about 5 μm, which showed almost no change, and it was confirmed that only the macroparticles protruding on the coating surface were removed by the barrel polishing treatment.

After rake-polishing the rake face of each surface-coated solid bob obtained in (1) to (3) above, the gear is cut under the following conditions to change the amount of flank wear and the edge face. When the presence or absence of welding of the workpiece was examined, the results shown in FIG. 1 and Table 1 were obtained. (Cutting conditions) Work material: SRC420 (HB: 140 to 160), M
2.5, PA 20 °, number of teeth 31, twist angle 30 ° 34 '
RH, tooth width 25 mm, cutting conditions: cutting speed / 100 m / min, feed 3.1 m
m / rev. Non-shift

[0027]

[Table 1]

As is clear from FIG. 1, (2)
(Comparative example) and (3) (Example) are (1) (Comparative example)
The wear resistance is 2.5 times or more as compared with. on the other hand,
As is clear from Table 1, in (2), welding of the work material was observed at the blade stand, whereas in (3), no such welding was observed at all.

This is because, in (2) and (3), a (Ti, Al) N film having higher wear resistance than that of TiCN in (1) is formed by arc discharge type ion plating. Further, in the example of (3), coarse microparticles protruding on the surface of the coating were removed by the surface polishing treatment after the coating was formed (see FIG. 2B), and the surface smoothness was also enhanced. Conceivable. In the comparative example of (1), the same degree of surface roughness as in the example of (3) was obtained, and no welding of the work material was observed, but the abrasion resistance of the coating itself was poor, and The desired high level cutting performance cannot be obtained.

Example 2 A JIS standard drill having an outer diameter of 11 mm was manufactured using high speed steel equivalent to JIS standard SKH51 as a base material, and a hard coating was formed on the surface of each drill blade by the following method.

(1a) Crucible type ion plating TiCN film (4 μm) (deposition conditions) Substrate temperature: 400 ° C. Bias voltage: −150 V Reaction gas pressure: 7 × 10 ⁻³ Torr (2a) Arc discharge type ion plating TiN film (4 μm) by method (deposition conditions) Substrate temperature: 400 ° C. Bias voltage: −150 V Reaction gas pressure: 7 × 10 ⁻³ Torr (3a) By arc discharge type ion plating method (Ti _0.5 , V _0.5 ). N film (4 μm) (film forming condition) Substrate temperature: 400 ° C. Bias voltage: −150 V Reaction gas pressure: 7 × 10 ⁻³ Torr (4a) Barrel polishing of the film formed by the above (3a) (thickness after polishing) (Approximately 4 μm) (Barrel polishing conditions) Polishing for 10 minutes using an alumina barrel tip with a diameter of 2 mm and # 800WA abrasive.

Using each of the obtained surface-coated drills, a cutting test was conducted under the following conditions to examine the cutting life and the welding condition of the work material, and the results shown in Table 2 were obtained. (Cutting conditions) Work material: S50C (drilling), 5 cuttings each Cutting speed: 30 m / min Feed: 0.22 mm / rev Cutting length: 20 mm (penetration) Cutting oil: Water-based emulsion cutting oil

[0033]

[Table 2]

As is clear from Table 2, (1a),
The comparative example of (2a) has a short cutting life, and the comparative material of (3a) shows remarkable welding of the work material, and neither of them can achieve the object of the present invention. On the other hand, in the example of (4a), almost no welding of the work material was observed and a very excellent cutting life was obtained.

[0035]

The present invention is constituted as described above, and provides a surface-coated tool which exhibits a very excellent wear life without causing problems such as welding of work materials and accompanying reduction in processing accuracy. I was able to do it.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the flank wear amount and the number of machining of a surface-coated tool obtained in an experimental example.

FIG. 2 is a diagram showing the surface roughness of coated tools obtained in Examples and Comparative Examples.

FIG. 3 is a drawing-substituting micrograph showing surface properties of coated tools obtained in Examples and Comparative Examples.

FIG. 4 is a conceptual explanatory view illustrating an ion plating method using an arc discharge method.

Claims (2)

[Claims] 1. A multi-component metal carbide, metal nitride or metal charcoal / nitride coating film containing two or more kinds of metal elements, in which macro particles are not substantially projected on the surface,
A hard coating-coated tool having wear resistance and welding resistance, characterized in that a hard coating having a crater with a depth of 2 to 2 μm is formed on the surface. 2. A multi-component metal carbide, metal nitride or metal carbon / nitride coating film containing two or more metal elements is formed on the surface of a tool base material by an arc discharge type ion plating method, A method for producing a wear-resistant and welding-resistant hard film-coated tool, characterized in that macro particles protruding on the film surface are removed to obtain a hard film having a crater with a depth of 0.2 to 2 μm.