KR102009409B1 - Sizing Roller Coated By Diamond Liked Coating Method Having Titanium Buffer Layer - Google Patents

Abstract

DLC coated sizing roller having a titanium buffer layer according to the present invention comprises a roller body made of a high strength material of SKD 11 or more; A titanium buffer layer having a thickness of 0.5 to 1 micrometers formed on the surface of the roller body by physical vapor deposition; And a diamond like coating (DLC) coating layer having a thickness of 1 to 2 micrometers formed on the titanium buffer layer by chemical vapor deposition.

Description

Sizing Roller Coated By Diamond Liked Coating Method Having Titanium Buffer Layer}

The present invention relates to a sizing roller, and more particularly, to a sizing roller having a DLC-coated surface and a titanium buffer layer, which has excellent abrasion resistance and a low friction coefficient and strong durability.

Multi-port extrusion is used to manufacture various products such as heat exchangers for vehicles, tube tubes for industrial and domestic air-conditioning systems, and various heat dissipation products.These products are made of aluminum material with high corrosion resistance, light weight, and high work efficiency. It is used a lot. These multi-extruded tubes are extruded to have a uniform width and thickness to fit the desired size and then cut into appropriate lengths, which is very important to maintain tolerances to the target thickness and width during the extrusion process.

Conventionally, titanium nitride (TiN) is coated on the surface of the roller using physical vapor deposition (PVD) to improve the wear resistance of the sizing roller that controls the width and thickness of the aluminum extrusion tube. The surface of the roller was coated with a diamond like carbon film (hereinafter, referred to as a 'DLC' coating) by using chemical vapor deposition (hereinafter, referred to as CVD).

However, the titanium nitride coated sizing roller has a friction coefficient of 0.7 on the surface and a film hardness of 1,500 to 2,000 HV, and generally has a lower wear resistance and durability than DLC coatings having a surface friction coefficient of 0.2 or less and a film hardness of 2,500 HV. There is no choice but to. On the other hand, in case of DLC coating, the coating layer itself has a high wear resistance and durability, but there is a problem in that the bonding force with the roller base metal, which is a metal material, is weak.

Accordingly, the technical problem to be solved by the present invention is a DLC coating having a titanium buffer layer, which is basically a very high hardness of the surface compared to the titanium nitride coating roller, abrasion resistance, low friction coefficient and strong durability compared to the conventional DLC coating roller It is to provide a sizing roller.

Technical problems to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above may be clearly understood by those skilled in the art from the following description. There will be.

DLC coated sizing roller having a titanium buffer layer according to the present invention for solving the technical problem is a roller body made of a high strength material of SKD 11 or more; A titanium buffer layer having a thickness of 0.5 to 1 micrometers formed on the surface of the roller body by physical vapor deposition; And a diamond like coating (DLC) coating layer having a thickness of 1 to 2 micrometers formed on the titanium buffer layer by chemical vapor deposition. The DLC coated sizing roller having the titanium buffer layer is characterized by a higher film hardness and a lower possibility of peeling of the DLC coating layer than the DLC coated sizing roller due to the titanium buffer layer.

The titanium buffer layer and the DLC coating layer are preferably formed by continuously performing a PVD process and a CVD process in one chamber.

The DLC coating sizing roller coating process having the titanium buffer layer includes: a surface treatment step of improving the roughness of the surface of the roller body and removing impurities in addition to the PVD and CVD processes for forming the titanium buffer layer and the DLC coating layer; And putting out the roller body into the chamber and heating it to a temperature of 150 to 200 degrees prior to depositing the titanium buffer layer to discharge gas contained in the roller body.

DLC coated sizing roller having a titanium buffer layer according to the present invention is the outermost DLC coating, so the surface hardness is very high and the friction coefficient is lower than the titanium nitride coating roller basically, wear resistance, durability compared to titanium nitride coating roller It has the advantage of excellent lubricity. At the same time, the sizing roller according to the present invention has a titanium buffer layer which improves the interfacial force between the roller surface and the DLC coating layer, so that the DLC coating layer is much less likely to peel off, which is much higher than the conventional DLC coating sizing roller. It may have durability.

1 shows a state diagram of use of a DLC coated sizing roller having a titanium buffer layer according to the present invention.
2 is an enlarged conceptual view of the surface portion of a DLC coated sizing roller having a titanium buffer layer according to the present invention.
3 is a flow diagram illustrating one example of a method of manufacturing a DLC coated sizing roller having a titanium buffer layer in accordance with the present invention.
Figure 4 is an enlarged photograph showing the rockwell test (rockwell test) results for the adhesion between the sizing roller having a titanium buffer layer and the sizing roller having a DLC coating layer according to the present invention.
FIG. 5 is an enlarged photograph showing a scratch test result for comparing adhesion between a sizing roller having a titanium buffer layer and a sizing roller having a DLC coating layer according to the present invention.
Figure 6 is a photograph showing the test results for comparing the wear of the sizing roller having a titanium buffer layer, the sizing roller having a DLC coating layer and the sizing roller having a titanium nitride coating layer according to the present invention.
FIG. 7 shows a test apparatus for comparing wear levels shown in FIG. 6.

DETAILED DESCRIPTION In order to fully understand the present invention, its operational or functional advantages, and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings which illustrate preferred embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, the present invention will be described in detail by explaining preferred embodiments of the present invention with reference to the accompanying drawings. Like reference numerals in the drawings may refer to like elements.

1 shows a state diagram of use of a DLC coated sizing roller 100 having a titanium buffer layer in accordance with the present invention. 2 is an enlarged conceptual view of a surface portion of a DLC coated sizing roller 100 having a titanium buffer layer in accordance with the present invention.

The sizing roller 100 according to the present invention serves to process the thickness of the extrusion tube passing therebetween to a predetermined thickness. On the other hand, although not shown in the drawings, the sizing roller according to the present invention may serve to apply pressure to the side of the extrusion tube in order to process the width of the extrusion tube to a predetermined width.

Although shown as SKD 11 in Figure 2, the body of the sizing roller 100 is preferably made of a high-strength material of SKD 11 or more that can basically provide the hardness and strength of the roller itself. On the other hand, the surface of the sizing roller 100 is 0.5 to 1 micrometer thick titanium buffer (titanium buffer) layer formed on the surface of the roller body and the chemical vapor deposition method on the titanium buffer layer 1 to 1 to 2 micrometers thick DLC (Diamond Like Coating) coating layer.

The titanium buffer layer may serve to prevent the DLC coating layer from peeling off by increasing the interfacial force between the roller body and the roller body. Therefore, the durability of the sizing roller 100 may be much higher than conventional sizing rollers that simply have a DLC coating layer.

Because the DLC coating layer can improve the hardness, lubricity, durability, friction characteristics, and corrosion resistance of the surface of the sizing roller 100, but the bonding stability of the roller body, which is a metallic material, is inevitably low. Or because a highly reactive titanium buffer layer keeps the bond of the DLC coating layer stable.

On the other hand, the titanium buffer layer and the DLC coating layer is preferably formed by continuously performing a PVD process and a CVD process in one chamber. In the case of the CVD process, the contamination by the impurities is generally high. If the process is performed by moving the sizing roller to the CVD chamber after performing the PVD process, the contamination is much higher. This is because continuous CVD fixation in the chamber where the performance is performed can significantly reduce the possibility of contamination.

3 is a flow diagram illustrating one example of a method of manufacturing a DLC coated sizing roller having a titanium buffer layer in accordance with the present invention.

First, surface treatment for improving the roughness of the sizing roller body of the SKD material and ultrasonic cleaning for removing impurities on the surface of the sizing roller body is made (S100). The reason for performing the surface treatment for improving the roughness is that the roughness of the sizing roller surface must be high to improve the deposition degree of the titanium buffer layer.

Then, an out gasing process of discharging the gas inside the sizing roller body by heating the body of the sizing roller for about 10 to 20 minutes at a temperature of 150 to 200 degrees is performed (S110). When this out-gassing process is performed, the deposition quality of the titanium buffer layer may be improved.

After the out-gassing step is performed, a DLC coating layer is deposited on the titanium buffer layer by a CVD method and a PVD process (S120) of depositing a 0.5 to 1 micrometer thick titanium buffer layer in a PVD method while the chamber is vacuumed. A CVD process (S130) for depositing is performed.

The reason why the titanium buffer layer is deposited in the PVD method is that in the case of titanium, it is easy to improve the interfacial adhesion between the DLC coating layer and the roller surface, but in a vacuum state because of its high reactivity with other materials (for example, a gas such as oxygen). This is because the titanium buffer layer having a very high surface activity can be formed by depositing titanium in the PVD method.

In the present invention, there is also a technical feature in performing the CVD process after performing the PVD process. In general, PVD process is performed at lower temperature than CVD fixation. If PVD process is performed and then CVD process is performed, the roller body, which is a metal material, is not placed in a sudden high temperature environment but is gradually placed in a high temperature environment, and thus the dimensional change due to the high temperature There is an advantage that tissue deformation can be minimized.

When the CVD process (S130) is completed, the coating is completed, the sizing roller is slowly cooled in the chamber for 1 to 2 hours and then taken out of the chamber (S140), the manufacturing process of the DLC coating sizing roller having a titanium buffer layer according to the present invention is Is done.

DLC coating sizing roller having a titanium coating layer according to the present invention prepared according to the above-described process, including a titanium coating layer of 0.5 to 1 micrometer thick and DLC coating layer of 1 to 2 micrometers thick formed thereon It has excellent film hardness of 3,500 HV, strong adhesion and durability.

Hereinafter, based on various test results according to the present invention, the performance of the DLC coated sizing roller having a titanium buffer layer and the conventional sizing roller are compared and analyzed. For reference, the test results were performed on specimens coated with the same size of SKD 11 base material (width X length X height: 15 mm X 15 mm X 4 mm) in each manner.

Table 1 shows the test results of the film hardness of the sizing roller having a titanium buffer layer and the sizing roller having a DLC coating layer and the sizing roller having a titanium nitride coating layer.

Referring to Table 1, for the same coating thickness of 1.5 micrometers, the film hardness of the sizing roller with the titanium nitride coating layer is 2,100 HV, and the film hardness of the sizing roller with the DLC coating layer is 3,200 HV, Accordingly, it can be seen that the film hardness of the sizing roller having a titanium buffer layer is 3,500 HV, which has a stronger film hardness than the existing sizing roller (particularly, compared to the DLC coated sizing roller).

Figure 4 is an enlarged photograph showing the rockwell test (rockwell test) results for the adhesion between the sizing roller having a titanium buffer layer and the sizing roller having a DLC coating layer according to the present invention.

Referring to FIG. 4, as a result of the Rockwell test applied with the same force, the cracks formed in the film of the DLC coated specimen having the titanium buffer layer according to the present invention are thinner and cleaner than the cracks formed in the conventional DLC coated specimen. It can be seen that the sizing roller according to the invention according to the invention has superior surface properties surface properties (adhesiveness) compared to DLC coated sizing rollers.

FIG. 5 is an enlarged photograph showing a scratch test result for comparing adhesion between a sizing roller having a titanium buffer layer and a sizing roller having a DLC coating layer according to the present invention. For reference, the scratch test was performed by scratching the surface of the specimen with the highest hardness diamond knife.

Referring to FIG. 5, it can be seen that the scratches generated in the conventional DLC coated specimens are wider than the scratches generated in the DLC coated specimens having the titanium buffer layer according to the present invention, and the scratch boundaries are not uniform. As a result, it can be seen that the sizing roller according to the present invention according to the present invention has excellent surface properties (scratch resistance) compared to the DLC coated sizing roller.

Figure 6 is a photograph showing the test results for comparing the wear of the sizing roller having a titanium buffer layer, the sizing roller having a DLC coating layer and the sizing roller having a titanium nitride coating layer according to the present invention. FIG. 7 shows a test apparatus for comparing wear levels shown in FIG. 6. In the test apparatus of FIG. 7, the friction ball is rotated based on the rotation of the rotation induction shaft by the motor, and the wear test is performed according to a mechanism in which the rotating friction ball wears the surface of the specimen. For reference, the result of FIG. 6 is a value calculated roughly by checking in 30 seconds whether the specimen is worn by rotating the rotating shaft at 3,000 rpm and the base metal under the coating layer is exposed in white.

Referring to FIG. 6, the sizing roller having a titanium nitride coating layer performs friction for abrasion test 7,500 times, and then the coating layer is worn, so that the roller body below the coating layer appears white. In the case of the sizing roller having the abrasion test rubbing 10,500 times, the coating layer was found to be worn, and in the case of the sizing roller according to the present invention, the coating layer was worn only after performing the abrasion test friction 21,000 times. Able to know. As such, it can be seen that the sizing roller according to the present invention has much better wear than the sizing roller having the DLC coating layer and the sizing roller having the titanium nitride coating layer.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the equivalents of the claims.

100: sizing roller 200: extrusion tube

Claims (3)

In the chamber, a roller body made of a high strength material of SKD 11 or higher is heated to a temperature of 150 to 200 degrees to discharge the gas contained in the roller body, and then the roller body may be subjected to physical vapor deposition. Forming a titanium buffer layer of 0.5 to 1 micrometer thickness on the surface; And
DLC having a thickness of 1 to 2 micrometers in a chemical vapor deposition method on the titanium buffer layer at a higher temperature than the physical vapor deposition process without moving the roller body after performing the physical vapor deposition. (Diamond Like Coating) DLC coating sizing roller manufacturing method having a titanium buffer layer, comprising the step of forming a coating layer. delete delete

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