JP2981930B2 - Surface treatment and coating method for aluminum and iron products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chromate treatment, a chemical conversion treatment, an electrodeposition coating, and a method for applying a coating to a product obtained by combining an aluminum molded product and an iron molded product.

[0002]

2. Description of the Related Art Some automobile bodies are formed by processing an aluminum material and an iron material into molded bodies having predetermined shapes, and combining the aluminum molded bodies and the iron molded bodies. Japanese Patent Application Laid-open No. Sho 6
What is described in 4-68493 is known.

[0003] That is, in the method described in the above publication, an aluminum molded article formed into a predetermined shape is subjected to chromate treatment with a treatment solution containing chromic acid, and the chromated aluminum molded article is subjected to electrodeposition coating. Combining an iron molded body molded into a predetermined shape with the electrodeposited aluminum molded body, forming the combined product with a chemical conversion treatment solution for forming a zinc phosphate film on the iron molded body, and then forming the iron. The molded body is subjected to electrodeposition coating.

According to this method, the chromic acid film formed on the aluminum molded body by the chromate treatment is coated with the coating film formed by the electrodeposition coating, so that the chromic acid film is formed in a subsequent chemical conversion treatment step. At the same time, it is possible to avoid a decrease in the appearance quality and rust prevention effect of the aluminum molded body.

[0005]

However, in the above-mentioned conventional method, a chemical conversion treatment and an electrodeposition coating are applied to the iron molded body in a state where the iron molded body before the electrodeposition coating is combined with the aluminum molded body coated with the electrodeposition. Therefore, the chemical conversion treatment and the electrodeposition coating of the portion of the iron molded body covered with the aluminum molded body become insufficient, and there is a problem that a problem arises in terms of rust prevention effect.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to enable a chemical conversion treatment and an electrodeposition coating to be performed on the entire surface of an iron molded body, thereby preventing a reduction in the rust prevention effect.

[0007]

Means for Solving the Problems In order to achieve the above object, a surface treatment and a coating method of a combination product of an aluminum molded product and an iron molded product according to the present invention include chromate treatment of an aluminum molded product molded into a predetermined shape. A step of electrodepositing the chromate-treated aluminum molded body; and forming the iron molded body in a state where the electrodeposited aluminum molded body is put into an iron molded body formed into a predetermined shape. A step of electrodepositing the chemically formed iron molded body, and a step of temporarily attaching the electrodeposited aluminum molded body to the electrodeposited iron molded body via a jig. And a step of painting the aluminum molded body.

The surface treatment and the coating method of the combination product of the aluminum molded product and the iron molded product of the present invention include a step of chromate-treating the aluminum molded product formed into a predetermined shape, and an electrodeposition coating of the chromated aluminum molded product. And a step of subjecting the iron molded body to a chemical conversion treatment in a state where the electrodeposited aluminum molded body is temporarily attached to the iron molded body formed into a predetermined shape via a jig, and temporarily attaching the aluminum molded body. A second feature is that the method further comprises a step of electrodepositing the iron molded body in a state in which the iron molded body is temporarily attached and a step of painting the iron molded body and the aluminum molded body in a state where the aluminum molded body is temporarily attached.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 5 show a first embodiment of the present invention. FIG. 1 is a flowchart showing the steps, FIG. 2 is a flowchart showing details of the chromate treatment step in FIG.
3 is a flowchart showing details of the chemical conversion treatment step of FIG. 1, FIG. 4 is an overall perspective view of the vehicle body in a charging step, and FIG.

In this embodiment, only the roof 1 of an automobile is made of an aluminum material and its body 2 is made of an iron material.
Are integrally joined.

In the flowchart of FIG. 1, first, a roof 1 as an aluminum molded body is formed from an aluminum material in a pressing step of step A. The subsequent chromate treatment step of Step B is for imparting the adhesion and rust prevention of the coating film similar to the iron material to an aluminum material having poor adhesion of the coating film, and details thereof are shown in the flowchart of FIG. . That is, in the degreasing step (step B ₁ ), after removing the oil and fat components attached to the roof 1 during the press working using an alkaline aqueous solution, a first washing step (step B ₂ ) and a _second washing step (step B ₁ ) to clean the roof 1 in step B _3). Subsequently, the roof 1 is immersed in a solution of chromic acid, hydrogen fluoride, and potassium ferricyanide in a chromic acid treatment step (step B ₄ ), and then a third rinsing step (step B ₅ ) and a fourth rinsing step (step B ₆₎ ) And a pure water washing step (step B ₇ ), and a drying step (step B ₈ ). By the chromate treatment process in the step B, a chromic acid film is formed on the surface of the aluminum roof 1. Then, the roof 1 that has been subjected to the chromate treatment is subjected to electrodeposition coating in the electrodeposition step of Step C.

On the other hand, in the pressing step of step D, the body main body 2 as an iron molded body is formed from an iron material. The body main body 2 and the roof 1 that has been subjected to the chromate treatment are integrated using a jig 3 in the charging step of step E. As is clear from FIGS. 4 and 5, the jig 3 is provided with a clamp arm 5 formed by bending a bar into a J-shape in a side view at four corners of a frame 4 having a bar formed in a rectangular shape. At the lower end of the clamp arm 5, with the locking member 7 which is fixed by screws 6 fitted to the front edge 2 ₁ and a trailing edge 2 ₂ of the roof opening of the main body 2 of the roof 1 is mounted is provided , the upper end of the clamp arm 5, the locking pins 8 to be engaged with the supporting portion 1 _1, 1 ₂ formed in front and rear edges of the roof 1 is upwardly provided. Thus, in the input step of the step E,
FIG. 4 shows a state in which the roof 1 is supported by the locking pins 8 of the jig 3.
The jig 3 is put into the floor of the body 2 together with the roof 1 as shown in FIG. By inserting the roof 1 into the body 2 as described above, the roof 1 can be held without protruding from the body 2 to the outside, so that the workability in the later-described chemical conversion process and electrodeposition coating process is improved. I do.

The chemical conversion treatment step of step F is for improving the adhesion and rust prevention of the coating film on the iron material.
The details are shown in the flowchart of FIG. That is, the oil component adhering to the body body 2 in the pressing step D is removed with an alkaline aqueous solution in the degreasing step (step F ₁ ), and then, is washed in the first washing step (step F ₂ ). Subsequently, in a surface conditioning step (step F ₃ ), neutralization with physodine is performed, and in a zinc phosphate treatment step (step F ₄ ), the sheet is immersed in a zinc phosphate solution containing hydrofluoric acid, nitrate, chloric acid, and the like. As a result, a zinc phosphate film is formed on the body 2. At this time, the roof 1 put into the body 2 is also immersed in the zinc phosphate solution together with the body 2, but the chromic acid film on the surface of the roof 1 is already covered by the electrodeposition coating. Therefore, the chromic acid film does not react with the zinc phosphate solution and elute into the zinc phosphate solution. Therefore, a zinc phosphate film can be formed on the body 2 while the chromic acid film formed on the roof 1 is held, and sludge due to elution of chromic acid is prevented from being mixed into the zinc phosphate solution. Is done.

When the zinc phosphate film is formed on the body 2 as described above, the second washing step (step F ₅ ), the third washing step (step F ₆ ), and the fourth washing step (step F ₇₎ ), A pure water washing step (step F ₈ ), and a drying step (step F ₉ ), and the chemical conversion treatment step of step F is completed.

Next, the electrodeposition step of step G is performed while the roof 1 is inserted into the body 2. At this time,
Since the roof 1 has already been subjected to electrodeposition coating in step C, its surface resistance becomes extremely large, and the roof 1 is insulated from the body 2. Therefore, even when the body main body 2 is subjected to electrodeposition coating, the roof 1
Is not applied again, and the thickness of the coating film on the body body 2 and the roof 1 is kept uniform. In addition, since the electrodeposition coating is performed in a state where the roof 1 is not mounted on the roof opening of the body body 2, the occurrence of unpainted portions in the roof opening is prevented, and the rust prevention effect is improved.

Next, in the temporary attaching step of step H, the body 2
The roof 1 is temporarily attached. That is, as shown in FIG. 5, the locking member 7 of the two clamping arms 5 before and after the jig 3, respectively engaged with the front edge 2 ₁ and a trailing edge 2 ₂ of the opening of the main body 2 By tightening the screws 6, the roof 1 is temporarily attached while being separated from the upper part of the body main body 2. Then, in the painting process of the next step I, the intermediate body and the top coat are applied to the temporarily attached body body 2 and roof 1. At this time, since the roof opening of the body main body 2 and the roof 1 are separated from each other, the coating spreads to the joint, and the rust prevention effect is improved.

In the parts assembling step of step J, parts such as a roof lock member and a roof lining are assembled to the roof 1 which has been coated, and in the parts assembling step of step K, the coating is completed. Interior parts, roof lock members, roof lining, electrical parts,
After assembling the undercarriage parts and the like, the roof 1 is finally attached to the roof opening of the body body 2 in the assembling step of Step L.

As described above, the formation step and the electrodeposition step are performed before the roof 1 is finally assembled to the body body 2, so that the joint between the body body 2 and the roof 1 is sufficiently coated. As a result, a decrease in the rust-preventing effect of the joint can be prevented.

FIG. 6 is a flowchart showing a second embodiment of the present invention. This embodiment is different from the first embodiment in that a temporary attaching step of step H is provided instead of the input step of step E in the first embodiment. . Therefore, the roof 1 that has been electrodeposited in step C and the body 2 that has been press-formed in step D are temporarily attached to the state shown in FIG. The electrodeposition step of Step G and the coating step of Step I are performed.

According to the second embodiment, since the formation step and the electrodeposition step are performed before the body body 2 and the roof 1 are finally assembled, it is possible to enhance the rust prevention effect of the joint. it can.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the present invention described in the appended claims. It is possible to make design changes.

For example, the aluminum molded body is not limited to the roof, but may be another part of the vehicle body such as a bonnet or a trunk. Further, the present invention is applicable to surface treatment and painting of objects other than automobiles.

[0024]

As described above, according to the first feature of the present invention, the iron molded body is subjected to the chemical conversion treatment and the aluminum molded body which has been subjected to the chromate treatment and the electrodeposition coating in the state of being put into the iron molded body. Electrodeposition coating not only prevents the chromic acid film of the aluminum molded product from being eluted during the chemical conversion treatment, but also covers the entire surface of the iron molded product, that is, the aluminum molded product after final assembly. Parts can also be completely converted and electrodeposited. As a result, the rust prevention effect at the joint of the iron molded body and the aluminum molded body is enhanced, and the durability thereof can be improved. In addition, in the chemical conversion treatment step in which the body body is immersed in the liquid tank and the electrodeposition coating step, the workability is improved because the aluminum molded body does not enter the body body and protrude to the outside.

According to a second feature of the present invention, the iron molded body is subjected to a chemical conversion treatment and an electrodeposition coating while the chromate-treated and electrodeposited aluminum molded body is temporarily attached to the iron molded body with a jig. Not only prevents the chromic acid film of the aluminum molded body from being eluted during the chemical conversion treatment, but also prevents the entire surface of the iron molded body, that is, the portion covered by the aluminum molded body after final assembly. It can be completely chemically treated and electrodeposited. As a result, the rust prevention effect at the joint of the iron molded body and the aluminum molded body is enhanced, and the durability thereof can be improved.

[Brief description of the drawings]

FIG. 1 is a flowchart showing steps of a first embodiment.

FIG. 2 is a flowchart showing details of a chromate treatment process.

FIG. 3 is a flowchart showing details of a chemical conversion treatment step.

FIG. 4 is an overall perspective view of the vehicle body in a loading step.

FIG. 5 is a partial cross-sectional view of the vehicle body in a tacking step.

FIG. 6 is a flowchart showing steps of a second embodiment.

[Explanation of symbols]

 1. Roof (aluminum molded body) 2. Body body (iron molded body) 3. Jig

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C25D 13/20 C25D 13/00 308 C23C 22/73

Claims (2)

(57) [Claims] 1. An aluminum molded body (1) molded into a predetermined shape.
, Chromate-treated aluminum electrode (1), electrodeposition coating, and iron-formed body (2) formed into a predetermined shape, electrodeposited aluminum body (1) A step of subjecting the iron molded body (2) to a chemical conversion treatment in a state in which the iron is charged, a step of electrodepositing the chemically formed iron molded body (2), and a step of curing the electrodeposited iron molded body (2). Coating the iron formed body (2) and the aluminum formed body (1) in a state where the electrodeposited aluminum formed body (1) is temporarily attached via the tool (3). Surface treatment and coating method for combination products of iron and iron moldings. 2. An aluminum molded article (1) molded into a predetermined shape.
A chromate treatment, an electrodeposition coating of a chromated aluminum molding (1), and an electrodeposition coating of an iron molding (2) formed into a predetermined shape via a jig (3). A step of subjecting the iron molded body (2) to a chemical conversion treatment with the aluminum molded body (1) temporarily attached thereto; and applying an electrodeposition coating to the iron molded body (2) while the aluminum molded body (1) is temporarily attached. Surface of a combined product of an aluminum molded body and an iron molded body, comprising: a step of coating the iron molded body (2) and the aluminum molded body (1) with the aluminum molded body (1) temporarily attached. processing,
Painting method.