JP2019151899A - Production method of aluminum component and production device of aluminum component - Google Patents

Abstract

To provide a production device of an aluminum component that can form an anodic oxide film, in which a crack is difficult to occur even in an improved speed of an anodic oxidation treatment.SOLUTION: A production device of an aluminum component comprises: an immersion tank 10 that holds electrolyte E including sulfuric acid and immerses a crude material W, which is a to-be-treated object composed of an aluminum or an aluminum alloy, into the electrolyte E; a power supply 20 that flows an electric current under a constant-voltage condition in which the crude material W is an anode, the electrolyte E is a cathode, a current density is 0.8 A/dmto 7.5 A/dm, and an applied voltage is 18 V or lower; and a controller 30 having a current integration unit 30a1 that calculates a current integral value in which the current has flown from the power supply 20 to the crude material W through the anode and the cathode, and a control unit 30a2 that calculates a thickness of an anodic oxide film produced on the basis of the current integral value calculated by the current integration unit 30a1 and controls the power supply 20 so that the treatment will be stopped when the calculated thickness reaches a specified value.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for manufacturing an aluminum part having an anodized film formed on the surface and an apparatus for manufacturing an aluminum part.

  Conventionally, an anodized film is formed on an aluminum part (see, for example, Patent Document 1).

  Anodized films formed on aluminum parts are known to be excellent in properties such as corrosion resistance, wear resistance, hardness, and insulation.

JP2015-102111A (Claims etc.)

  Although it is an anodic oxide film having excellent characteristics, a long-time treatment (about 20 to 60 minutes) is required to form the anodic oxide film on the surface of the rough material. Since the generation of the anodized film is proportional to the amount of current flowing, it is necessary to improve the current density in order to improve the generation rate of the anodized film and shorten the processing time.

  However, if the anodization treatment is performed simply by increasing the current density, the ductility of the obtained anodized film may be reduced and cracks may occur due to external force. There is a possibility that it may cause breakage when an anodized film is formed on a part used in a high temperature environment.

  The present invention has been completed in view of the above circumstances, and an object to be solved is to provide a method for manufacturing an aluminum part capable of forming an anodic oxide film that hardly causes cracks even if the speed of anodizing treatment is increased.

  Furthermore, another object to be solved is to provide an aluminum component manufacturing apparatus suitable for the above-described aluminum component manufacturing method.

(1. Manufacturing method of aluminum parts)
In order to solve the above-mentioned problems, the present inventors have conducted intensive studies. As a result, the cell size of the anodic oxide film generated to determine whether cracks are likely to occur in the anodic oxide film generated on the surface of the coarse material is determined. I came up with the idea of paying attention. From the results of Examples to be described later, it can be seen that in the anodized film, the cell size formed increases as the applied voltage increases, and the cell size can be reduced to 40 nm or less by further reducing the applied voltage to 18 V or less. It became possible and the knowledge that the generation of cracks could be suppressed was obtained. Based on these findings, the following invention has been completed. In the present specification, “cell size of anodized film” refers to the distance between 703 micropores in adjacent 702 coated cells based on the 701 schematic diagram of JIS H0201: 1998.

That is, in the method for producing an aluminum part according to the present invention, a rough material made of aluminum or an aluminum alloy is used as an anode, and the anode is brought into contact with an electrolyte containing sulfuric acid together with the cathode, and the current density is 0.8 A / dm. Anodization is performed by passing a current between the anode and the previous cathode under a constant voltage condition of ^{2 to} 7.5 A / dm ² and an applied voltage of 18 V or less.

  Even if the current density is increased in the anodizing treatment to improve the generation rate of the anodized film, the generation of cracks is suppressed by setting the applied voltage to 18 V or less and the cell size of the anodized film to a certain value or less. Became possible. In particular, the cell size can be stabilized by processing at a constant voltage.

(2. Aluminum parts manufacturing equipment)
An apparatus for manufacturing an aluminum component according to the present invention includes an immersion tank that holds an electrolytic solution containing sulfuric acid, uses a rough material made of aluminum or an aluminum alloy as an anode, and is immersed in the electrolytic solution together with a cathode. A power supply device for passing a current between the anode and the previous cathode under a constant voltage condition of a current density of 0.8 A / dm ^{2 to} 7.5 A / dm ² and an applied voltage of 18 V or less, and from the power supply device to the anode Based on the integrated value of the current calculated by the current integrating unit and the current integrating unit that calculates the integrated value of the current flowing between the cathode and the cathode, the thickness of the anodized film that is generated is calculated. And a control device having a control unit for controlling the power supply device so as to end the processing when the predetermined value is reached.

It is a schematic diagram which shows the manufacturing apparatus of the aluminum component in embodiment. It is the graph which showed the time-dependent change of the electric current when implementing the manufacturing method of an aluminum component in an Example. It is the graph which showed the correlation with the integrated value of the electric current which flowed between the anode and the cathode, and the thickness of the produced | generated anodic oxide film.

(1. First embodiment: Method for manufacturing aluminum part)
(1-1. Configuration)
The manufacturing method of the aluminum component of this embodiment is demonstrated below. The manufacturing method of the aluminum component of this embodiment performs anodizing treatment in an electrolytic solution containing sulfuric acid on a rough material made of aluminum or an aluminum alloy, and forms an anodized film on the surface of the material. This is a method of making an aluminum part. The material constituting the coarse material is aluminum or an aluminum alloy, and the aluminum alloy is not particularly limited as long as it contains an aluminum element as a main component. Furthermore, it is sufficient if it has a structure in which aluminum or an aluminum alloy is exposed on the surface of the rough material, and the material forming the interior is not particularly limited.

  As an aluminum part, an anodic oxide film that is not easily cracked by an external force can be formed. Therefore, it can be applied to any product part, but it is preferably applied to a part to which a particularly large external force is applied. . For example, a valve body applied to high-pressure gas.

This manufacturing method includes a first step and a second step and other necessary steps.
The first step is a step in which a rough material to be treated is used as an anode and is brought into contact with the electrolyte together with the cathode. The electrolytic solution contains sulfuric acid. Preferred conditions for the electrolyte will be described later. For example, the contact with the electrolytic solution may be performed by immersing a crude material in the electrolytic solution. The cathode is not particularly limited.

The second step is a step in which an anodic oxidation treatment is performed by passing a current between the anode and the cathode under a constant voltage condition of a current density of 0.8 A / dm ^{2 to} 7.5 A / dm ² and an applied voltage of 18 V or less. .

  The current density is preferably as high as possible because the speed at which the anodized film is formed is increased by setting the current density to be equal to or higher than this lower limit. Further, when the current density is set to the upper limit value or less, “film burn” does not occur in the anodized film formed. “Film burn” is presumed to occur when the current density is high and the current does not flow uniformly but concentrates on a part of the film. The properties of the anodized film obtained are not sufficient.

  A method for controlling the current density can be realized by employing an appropriate electrolyte. An appropriate electrolytic solution is an electrolytic solution adjusted to have a resistance value that falls within the range of the current density described above. The adjustment of the resistance value can be realized by controlling the sulfuric acid concentration and temperature of the electrolytic solution. By increasing the sulfuric acid concentration and temperature, the resistance value decreases and the current density can be increased. The concentration of the sulfuric acid contained in the electrolytic solution is preferably 150 g / L to 300 g / L. The temperature of the electrolytic solution is preferably 10 ° C. or higher and 30 ° C. or lower.

  As the magnitude of the voltage to be applied, a higher one is desirable because the current density is easily improved. The lower limit is not particularly limited, but the voltage at which an anodic oxide film can be formed on the surface by the oxidation-reduction reaction is the theoretical lower limit.

  In the second step, the film formation state can be accurately calculated based on the integrated value of the current value obtained by measuring and integrating the value of the current flowing between the anode and the previous cathode. In the prior art, it was normal to perform anodization treatment with a constant current density, so the treatment time and the amount of current passed were proportional, and the anodized film was formed by measuring the treatment time. It was possible to calculate the speed.

(1-2. Effects)
Since it has the above-described configuration, the aluminum part manufacturing method of this embodiment can limit the voltage to 18 V or less even if the current applied to the rough material varies due to factors such as the state of the electrolyte. Since the size can be within an appropriate range (40 nm or less), generation of cracks can be suppressed. And it became possible to enlarge the production | generation speed | rate of an anodic oxide film by enlarging an electric current value in the state which restrict | limited the upper limit of the power supply. That is, it became possible to produce an anodized film that could suppress the formation of cracks at a high rate.

(2. Second embodiment: Aluminum component manufacturing apparatus)
(2-1. Configuration)
The aluminum component manufacturing apparatus of the present embodiment is an apparatus that can suitably carry out the above-described aluminum component manufacturing method. As shown in FIG. 1, the aluminum component manufacturing apparatus of the present embodiment includes a dipping bath 10, a power supply device 20, a control device 30, a temperature adjusting means 40, an anode wiring 21, a cathode wiring 22, and cathodes 25 and 26. .

  The immersion tank 10 is a member that holds the electrolytic solution E, and the rough material W that is the object to be processed can be immersed therein. Since the electrolytic solution E is as described in the above-mentioned column of the method for manufacturing an aluminum part, further description is omitted.

  The power supply device 20 is a constant voltage power supply. The voltage to be output is 18 V or less, as described in the column of the method for manufacturing an aluminum part described above. An anode wiring 21 and a cathode wiring 22 are connected from the power supply device 20. A coarse material W is connected to the anode wiring 21. Cathodes 25 and 26 are connected to the cathode wiring 22. The cathodes 25 and 26 and the coarse material W are fixed to a jig (not shown) so as to be disposed in the electrolytic solution E with a gap therebetween.

  The control device 30 includes a power supply device control unit 30 a that controls the power supply device 20 and a temperature adjustment unit control unit 30 b that controls the temperature adjustment unit 40. A control line 31 is connected to the power supply controller 30a. A control line 32 is connected to the temperature adjusting means control unit 30b.

  The power supply device control unit 30a has a current integration unit 30a1 and a control unit 30a2, integrates the current value output by the current integration unit 30a1 with time, and the control unit 30a2 generates an anodic oxide film generated based on the integration value. Control is performed to stop the output of the voltage from the power supply device 20 when the thickness is calculated to reach the target thickness.

  Based on the temperature of the electrolytic solution E measured by the temperature adjusting unit 40, the temperature adjusting unit control unit 30b controls the temperature adjusting unit 40 so that the temperature of the electrolytic solution E becomes a target value. About the target value of the temperature of the electrolyte solution E, it is as having demonstrated with the manufacturing method of the aluminum component mentioned above.

  The temperature adjusting means 40 is disposed so as to be immersed in the electrolytic solution E, and measures the temperature of the electrolytic solution E, a stirring unit (not shown) for stirring the electrolytic solution, a heater (not shown) for heating the electrolytic solution E, and the electrolytic solution E. And a thermometer (not shown).

  In addition, although the aspect with one coarse material W is described in FIG. 1, the aspect which processes simultaneously about the several coarse material W is also employable. In that case, it is necessary to prepare a plurality of sets of the power supply device 20, the power supply control unit 30 a, the cathodes 25 and 26, the anode wiring 21, and the cathode wiring 22 in accordance with the number of coarse materials W. About immersion tank 10, electrolyte solution E, temperature control means 40, and temperature control means control part 30b, it can also prepare as a number smaller than the number of the plurality of coarse materials W by making a plurality of coarse materials W into a set.

(2-2. Effects)
Since the aluminum part manufacturing apparatus of the present embodiment has the above-described configuration, the cell size can be limited to 18 V or less even if the voltage applied to the rough material varies due to factors such as the state of the electrolyte. Can be contained in an appropriate range (40 nm or less), and therefore, generation of cracks can be suppressed. And it became possible to enlarge the production | generation speed | rate of an anodic oxide film by enlarging an electric current value in the state which restrict | limited the upper limit of the power supply. That is, it became possible to produce an anodized film that could suppress the formation of cracks at a high rate.

  The method and apparatus for producing an aluminum part of the present invention will be described in detail based on the following examples.

(Test 1)
The relationship between the cell size of the anodized film and the applied voltage was evaluated. The applied voltages were 18V (Test Example 1-1), 20V (Test Example 1-2), and 22V (Test Example 1-3). The peak value of the current density that flowed through each was 1 A / dm ² in Test Example 1-1, 5 A / dm ² in Test Example 1-2, and 7.5 A / dm ² in Test Example 1-3. Therefore, in order to make the thickness of the generated anodic oxide film constant, the processing time was 900 seconds for Test Example 1-1, 180 seconds for Test Example 1-2, and 120 seconds for Test Example 1-3. About the obtained rough material in which the anodic oxide film was formed, it processed at 165 degreeC for 1 hour. Then, the state in the cross section in the direction orthogonal to the direction in which the anodized film was formed was observed with a metal microscope and SEM, and the presence or absence of cracks in the anodized film and the cell size were measured.

  As a result, only Test Example 1-1 had no cracks. The cell size was 40 nm in Test Example 1-1, 50 nm in Test Example 1-2, and 55 nm in Test Example 1-3. Therefore, it was found that cracking can be suppressed by applying a voltage of 18 V or less. It was found that the crack could be suppressed because the cell size could be reduced to 40 nm or less. Further, it was confirmed that an anodized film was generated and no crack was generated even when the applied voltage was 13V.

(Test 2)
Regarding the presence or absence of cracks and the change in cell size when the current value (peak value) was changed under the conditions of Test Example 1 where the crack was not generated under the conditions of Test 1 (the applied voltage was 18 V). Study was carried out. Table 1 shows the values of the flowed current. The current value was controlled by adjusting the temperature of the electrolyte and the concentration of sulfuric acid contained as shown in Table 1. The same evaluation as in Test 1 was performed on the crude material on which the anodized film was formed. Furthermore, the appearance was observed to confirm the presence or absence of film burn. The results are shown in Table 1.

As is apparent from Table 1, no film burning or cracking occurs in the current density range of 0.98 A / dm ² (Test Example 2-1) to 7.19 A / dm ² (Test Example 2-5). I understood. In this case, when the sulfuric acid concentration of the electrolytic solution is 200 g / L, the current density increases as the temperature rises when the electrolytic solution temperature ranges from 10 ° C. (Test Example 2-1) to 30 ° C. (Test Example 2-5). It was found that the anodized film formed in this range does not cause film burning and cracks. The cell size was 40 nm, and the cell size did not change even when the current density changed.

When the sulfuric acid concentration of the electrolytic solution was 300 g / L, it was found that the anodic oxide film produced at the electrolytic solution temperature of 15 ° C. (Test Example 2-6) did not cause film burning and cracking. The cell size was 40 nm, and the cell size did not change even when the current density changed. Film burning and generation of cracks were observed at electrolyte temperatures of 20 ° C. (Test Example 2-7) and 25 ° C. (Test Example 2-8). In this case the current density electrolyte temperature 20 ° C. At 11.4 A / ^dm 2, a 25 ° C. In 68.6A / dm ^2, a large Joule heat since the current density electrolyte temperature becomes high too high It was speculated that this was caused by the occurrence of

  It has been found that the sulfuric acid concentration of the electrolytic solution is preferably 200 g / L because the variation in the thickness of the anodized film formed is smaller than that of 300 g / L.

(Test 3)
FIG. 2 shows the change with time of the current value when the applied voltage is fixed at 18V. As is clear from FIG. 2, the current value changed with time, but it was confirmed that there was a substantial correlation between the integrated value of the current and the thickness of the generated anodic oxide film (see FIG. 3). Therefore, it was confirmed that the thickness of the anodized film can be measured by calculating the integral value of the current density.

    DESCRIPTION OF SYMBOLS 10 ... Immersion tank 20 ... Power supply device 21 ... Anode wiring 22 ... Cathode wiring 25, 26 ... Cathode 30 ... Control device 30a ... Power supply device control part 30b ... Temperature adjustment means control part 40 ... Temperature adjustment means W ... Rough material (to-be-processed) Target)

Claims (5)

A rough material to be treated made of aluminum or an aluminum alloy is used as an anode, and brought into contact with an electrolytic solution containing sulfuric acid together with a cathode.
A method for producing an aluminum component, wherein anodization is performed by passing a current between the anode and the previous cathode under a constant voltage condition of a current density of 0.8 A / dm ^{2 to} 7.5 A / dm ² and an applied voltage of 18 V or less.   The manufacturing method of the aluminum component of Claim 1 which controls the thickness of the anodic oxide film produced | generated based on the integral value of the electric current which flowed between the said anode and a previous cathode.   The method for producing an aluminum part according to claim 1 or 2, wherein the electrolytic solution has a sulfuric acid concentration of 150 g / L to 300 g / L. A dipping tank that holds an electrolytic solution containing sulfuric acid, is made of aluminum or an aluminum alloy and is a rough material to be treated as an anode, and is immersed in the electrolytic solution together with the cathode;
A power supply device for passing a current between the anode and the previous cathode under a constant voltage condition of a current density of 0.8 A / dm ^{2 to} 7.5 A / dm ² and an applied voltage of 18 V or less;
Based on the integrated value of the current calculated by the current integrating unit calculated by the current integrating unit that calculates the integrated value of the current that flows between the anode and the cathode from the power supply device, the thickness of the generated anodic oxide film A control device having a control unit for calculating and controlling the power supply device so as to end the processing when the calculated thickness reaches a predetermined value;
An apparatus for manufacturing an aluminum part. Temperature adjusting means for adjusting the temperature of the electrolyte solution;
The said control apparatus is a manufacturing apparatus of the aluminum component of Claim 4 which controls the said temperature adjustment means so that the temperature of the said electrolyte solution may become a fixed value within the range of 10 degreeC or more and 30 degrees C or less.

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