JPH1147822A - Extrusion jig - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the cohesion of a material to be extruded and foreign matter, etc., to the surface of an extrusion jig and to improve the degree of tight adhesion of the films formed on the surface and an extrusion jig base body by forming a TiN film on the surface of this base body and forming a BN film of a specific thickness on this TiN film. SOLUTION: The TiN film is formed on the surface of the extrusion jig consisting of iron and steel materials. The thickness of the TiN film is preferably >=2 μm by taking durability into consideration. The BN film having a film thickness of <=3 μm is formed on the TiN film. The TiN film and the BN film may be deposited by a physical vapor deposition method (PVD method), for example, an ion plating method or a chemical vapor deposition method (CVD method), for example, a thermal CVD method. The deposition of the TiN film and the deposition of the BN film are preferably executed continuously within the same chamber. These coating films are effective for extrusion of a lead alloy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extruding jig used for extruding a metal or a polymer, and more particularly to an extruding jig in which adhesion of a material to be extruded and foreign matters to the surface thereof is suppressed.

[0002]

2. Description of the Related Art When a metal or a polymer is repeatedly extruded, a material to be extruded such as a metal or a polymer extruded on a jig used for the extrusion, particularly a jig used for a heat extrusion is solidified. To wear. Also, depending on conditions such as heat and pressure during extrusion, foreign substances such as intermetallic compounds or oxides are formed,
These may adhere to the surface of the jig used.

For this reason, the accuracy of the extruded product may be reduced, foreign matter may be mixed into the extruded product, or seizure of the jigs may occur. And it is difficult to stably perform extrusion for a long time.

[0004] In order to prevent these, a coating treatment of, for example, a chromium plating film, a TiN film or the like is performed, but a sufficient effect has not been obtained. Therefore, diamond-like carbon (hereinafter referred to as DL
C) has been developed. The Vickers hardness Hv of the chromium plating film is about 1000 and the Vickers hardness of the TiN film is about 2000, whereas the Vickers hardness of the DLC film is 3000 or more, which is excellent in terms of hardness.

[0005]

However, when a DLC film is formed on a steel material widely used as a material for an extrusion jig, when the thickness of the DLC film exceeds 1 μm, cracks occur in the film due to internal stress. Cheap. Furthermore, D
Since the LC film is made of carbon, carbon diffuses into the steel material when used for a long period of time. For this reason, the film thickness is gradually reduced, and the effect of preventing adhesion is reduced. Further, since the amount of carbon in the steel material increases, the jig may be embrittled and damaged.

In order to prevent such inconvenience, even if a DLC film is formed after coating a substrate with a conventionally used chromium plating film or TiN film over a thickness of several μm or more, it is difficult to obtain a conventional film. There is a problem that it is easily peeled off due to low adhesion to the DLC film.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is possible to suppress the adhesion of a material to be extruded and foreign matters to the surface thereof and to prevent the adhesion from being formed on the surface. It is an object of the present invention to provide an extrusion jig having a high degree of adhesion between the extrusion jig and the extrusion jig base.

[0008]

An extrusion jig according to the present invention comprises an extrusion jig base and a T formed on the surface of the base.
iN film and a thickness of 3 μm formed on the TiN film.
It has the following BN film.

In the present invention, TiN is applied on the surface of the substrate.
Since the film is formed and the BN film is formed on it,
Adhesion of the material to be extruded and foreign matter to the extrusion jig is suppressed.
Further, since the adhesion between the TiN film and the BN film is high and the thickness of the BN film is appropriate, peeling of the film is prevented.

The base is preferably formed of a steel material in view of the strength required for the extrusion process.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of intensive experiments and research conducted by the present inventors to solve the above problems, a TiN film is formed on the surface of an extrusion jig, and a BN film having an appropriate thickness is formed thereon. It has been found that the formation can prevent the material to be extruded, foreign matter, etc. from adhering to the surface of the jig, and also prevent peeling of the film.

The hardness Hv of the BN film is about 3000, which is equivalent to the hardness of the DLC film, and has the same effect of preventing adhesion to the jig surface as the DLC film. Furthermore, the degree of adhesion between the BN film and the TiN film is high, and the BN film is not easily separated from the TiN film.

The thickness of the BN film is 3 μm or less.
With the current film forming technology, when the film thickness of the BN film exceeds 3 μm, strain is accumulated in the film, cracks occur in the BN film due to strong internal stress as in the case of the DLC film, and peeling occurs. Therefore, the thickness of the BN film is set to 3 μm or less.

On the other hand, the TiN film has an appropriate hardness and a high degree of adhesion not only to the BN film but also to a steel material which has been widely used as a substrate of a conventional extrusion jig. Although the required characteristics can be obtained even if the TiN film is thin, it is desirable that the film thickness be 2 μm or more in order to obtain stable characteristics over a long period in consideration of durability.

The TiN film and the BN film can be formed by physical vapor deposition (PVD), for example, by ion plating, or by chemical vapor deposition (CVD), for example, by thermal CVD.
It can be formed by a VD method. An extremely high degree of adhesion can be obtained by continuously forming the TiN film and the BN film in the same chamber without opening to the atmosphere. However, a high degree of adhesion and an anti-adhesion effect can be obtained even if it is opened when it is difficult not to open to the atmosphere.

The coating film thus configured is
For example, it is formed on a base made of a steel material.

The coating film thus configured is particularly effective for extruding a lead alloy.

[0018]

EXAMPLES Examples of the extruding jig according to the present invention will be specifically described below in comparison with comparative examples outside the scope of the claims.

First Embodiment First, tool steel (Ni-Cr-M) was used as a test material in the first embodiment.
o) The thickness of 5.1 ± 0.2 μm Ti
An N film and a BN film having a thickness of 0.5 ± 0.1 μm were sequentially formed by an ion plating method. At this time, the Vickers hardness Hv was measured before the film was formed, immediately after the TiN film was formed, and after the BN film was formed. The results are shown in Table 1 below.

[0020]

[Table 1]

Next, a test material of a comparative example was prepared by forming a coating film shown in Table 2 below on the surface of a tool steel material.

[0022]

[Table 2]

In Comparative Example 2, a BN film was formed on the surface of the tool steel in the same manner as in Example 1. Further, in Comparative Example 3, the thickness of the film was 0.2 ± 0.2 mm on the surface of the tool steel by ion beam sputtering using a carbon target.
A 0.05 μm DLC film was formed. In Comparative Example 4, a TiN film was formed as in Example 1, and then a DLC film was formed thereon as in Comparative Example 3.

Next, by cutting a part of the test material of each Example and Comparative Example, an edge portion where the tool steel material and the film were exposed was formed. Then, as a heat shock test,
The heat treatment of holding the sample in a thermostat at 350 ° C. for 15 minutes and the quenching process of quenching in water were repeated five times. Then, the test material was observed using a scanning electron microscope.

[0025] In this result, in Example 1, 3μm following BN film via a TiN film is formed, peeling anywhere including the edge portion was not observed.

In Comparative Example 2, since no TiN film was formed between the tool steel material and the BN film, peeling was observed at the edge.

In Comparative Example 3, since the DLC film was formed on the tool steel material, the entire surface was peeled off by one heat treatment and quenching treatment.

In Comparative Example 4, DLC was formed on the TiN film.
Since the film was formed, peeling occurred on the entire surface immediately after the film was formed.

Second Example First, a coating film shown in Table 3 below was formed on the surface of a screw of an extruder.

[0030]

[Table 3]

The TiN film and BN film of Example 5 and Comparative Example 6 were formed in the same manner as in Example 1.

Next, using a housing having no coating film formed thereon and a screw having the coating film of each embodiment or comparative example formed on the surface thereof, 400 weight pp.
The mTe-400 wt ppm Cu-Pb alloy was extruded for 10 t. After that, the appearance of the screw was observed, and further, the adhered substances such as foreign substances and oxides adhered to the screw were peeled off,
The weight of the deposit was measured. The results are shown in Table 4 below.
Shown in In the column of appearance in Table 4, ○ indicates that almost no adhesion was observed, Δ indicates that significant adhesion was locally observed, and × indicates that significant adhesion was observed in a wide range. It indicates that it was done.

[0033]

[Table 4]

As shown in Table 4 above, in Example 5, since an appropriate coating film was formed on the surface of the screw, adhesion of foreign matters and oxides was suppressed.

On the other hand, in Comparative Example 6, since only the TiN film was formed on the surface of the screw, the amount of adhesion was extremely large.

In Comparative Example 7, since the chromium plating film was formed on the surface of the screw, the amount of adhesion was large.

Third Embodiment The thickness of the TiN film, the thickness of the BN film, and the Vickers hardness Hv
The relationship with was investigated. First, a test material was prepared by forming a TiN film having a film thickness shown in Table 5 below on a surface of a tool steel material and forming a BN film having a film thickness shown in Table 5 below thereon.

[0038]

[Table 5]

Next, in the same manner as in the first embodiment, an edge portion was formed, a heat shock test was performed five times, and observation was performed using a scanning electron microscope. The results are shown in Table 6 below. Incidentally, those where the peeling including an edge portion was observed ◎, peeled off after 5 times of test peeling in the edge portion is observed what was observed that cracks occurred ○, after 5 tests The sample was evaluated as Δ, and the sample in which peeling was observed at the edge after one test was evaluated as ×.

[0040]

[Table 6]

As shown in Table 6 above, Examples 8 to 12
In, because it is formed BN film of suitable thickness, peeling anywhere including the edge portion was not observed.
In particular, in Examples 8 to 11, the occurrence of cracks was also prevented.

On the other hand, in Comparative Examples 13 and 14, B
Since the thickness of the N film exceeded the upper limit of the range of the present invention, peeling was observed at the edge.

[0043]

As described in detail above, according to the present invention,
Since the TiN film is formed on the surface of the base of the extrusion jig and the BN film is further formed thereon, it is possible to suppress the adhesion of the material to be extruded and foreign matter to the extrusion jig. Also, Ti
Since the adhesion between the N film and the BN film is high and the thickness of the BN film is appropriate, peeling of the coating film due to heat shock or the like is prevented, and the surface hardness of the extrusion jig is high and scratches are hardly generated. Therefore, the accuracy of the extrusion jig can be maintained for a long period of time.

Claims (2)

[Claims] An extrusion jig comprising: an extrusion jig base; a TiN film formed on a surface of the base; and a BN film formed on the TiN film and having a thickness of 3 μm or less. jig. 2. The extrusion jig according to claim 1, wherein the base is made of a steel material.