KR100823997B1 - Process for phosphating metal parts - Google Patents

Abstract

The present invention discloses a method for treating phosphate of metal parts. According to the invention, the step of injecting a metal component; Washing the injected metal parts; Degreasing the surface of the washed metal part with an alkali degreasing agent; Washing the degreased metal parts; Forming a phosphate coating on the surface of the washed metal part; And washing, drying, and discharging the metal parts having the phosphate coating formed thereon.

Description

Process for phosphating metal parts

1 is a process flow diagram for a phosphate treatment method of a metal part according to a conventional example.

2 is a view showing a state in which a phosphate film is formed on the metal surface by the phosphate treatment method shown in FIG.

Figure 3 is a process flow diagram for a phosphate treatment method of a metal component according to an embodiment of the present invention.

4 is a view showing a state in which a phosphate film is formed on the metal surface by the phosphate treatment method shown in FIG.

The present invention relates to a method for treating phosphate of a metal part, and more particularly, to a method for treating phosphate of a metal part, which is not only environmentally friendly and harmless to the human body, but also dense phosphate crystals can be obtained when forming a phosphate coating.

Automobiles and the like are made up of various parts, and among these parts, metal parts which have been machined are often subjected to phosphate treatment for the purpose of improving the corrosion resistance on the surface thereof or improving the adhesiveness with the adhesive during painting. . Phosphate treatment chemically reacts metals such as steel with dilute phosphoric acid to change the intrinsic properties of metals by making the surface of the metal into soluble crystalline phosphate. Phosphate treatment is also known as parkerizing.

Such phosphate treatment is used to increase the corrosion resistance or to increase the wear resistance of the metal. In addition, phosphate treatment may be used for the underlaying of a coating, or for cold processing, for example, to reduce when there is a very large friction between the surface of the steel and the die during drawing of the steel.

1 illustrates a phosphate treatment method of a metal part according to a conventional example. As shown in FIG. 1, in the phosphate treatment method, a step of injecting a metal part (S11), a step of degreasing the surface of the injected metal part (S12), and forming a phosphate film on the surface of the degreased metal part. Step S13, washing the metal parts having the phosphate film formed thereon (S14), washing the washed metal parts (S15), drying and discharging the washed metal parts (S16) It includes.

Here, the degreasing step is for removing oil remaining due to the processing oil on the surface of the metal part after the metal part has been machined. In this case, when foreign matter such as iron is attached to the surface of the metal part, a process of removing it together with residual oil is also involved. As described above, for degreasing to remove residual oil or the like from the surface of the metal part, a solvent-based degreasing agent such as trichlorethylene (TCE) or the like is generally used.

By the way, when the solvent-based degreasing agent such as TCE is used, there is an advantage of excellent cleanability, fast drying, non-flame-retardant material, but there is a strong corrosiveness to corrode metal parts. In addition, since it is suspected to be a carcinogenic substance harmful to the human body and causes environmental pollution such as ozone layer destruction phenomenon, it is expected to be banned from 2010, and it is difficult to dispose of it since it must be disposed of after use. Not only this, there is a costly problem accordingly.

In addition, when the phosphate film is formed by the phosphate treatment method of FIG. 1, there may be the following problems.

FIG. 2 illustrates a state in which a phosphate film is formed on the surface of iron by the phosphate treatment method of FIG. 1. Here, the phosphate crystals shown are magnified 500 times by SEM. Then, the surface of the metal was degreased using TCE as the solvent-based degreasing agent, and then a phosphate film was formed using a conventional phosphate coating agent.

As shown in FIG. 2, the shape of the phosphate crystal has a needle-like structure, which may be vulnerable to bending or external impact, and may also deteriorate the anchor effect with the adhesive during coating. . Here, the anchor effect means that the adhesive penetrates into the voids on the surface of the adherend to act as a nail or wedge. In addition, since the size of the phosphate crystals are generally large, the surface area relative to the weight of the phosphate film may be small, and thus there may be a problem of low adhesiveness during coating.

The present invention is to solve the above-mentioned problems, it is an object of the present invention to provide a phosphate treatment method of environmentally friendly metal parts that can be harmless to humans.

Another object of the present invention is to provide a method for treating phosphate of metal parts in which dense phosphate crystals can be obtained in forming a phosphate film.

Phosphate treatment method of a metal part according to the present invention for achieving the above object, the step of introducing a metal part; Washing the injected metal parts; Degreasing the surface of the washed metal part with an alkali degreasing agent; Washing the degreased metal parts; Forming a phosphate coating on the surface of the washed metal part; And washing, drying, and discharging the metal parts having the phosphate coating formed thereon.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

3 is a process flowchart of a phosphate treatment method of a metal component according to an embodiment of the present invention. Here, the arrow shown by the solid line shows the movement path of a metal component.

Referring to FIG. 3, in order to perform phosphate treatment on a metal part, first, a metal part is added (S110). Here, the metal parts are prepared in advance through various machining to be employed in automobiles and the like.

After injecting the metal parts, the injected metal parts are washed out (S120). Here, hot water is a process of washing a metal part with hot water containing a rust preventive agent, and primarily removes oil remaining on the surface of the metal part due to the use of processing oil during machining. This hot water washing step (S120) is to first remove the residual oil before removing the residual oil from the surface of the metal parts in the subsequent degreasing step (S130), so that the degreasing can be made sufficiently in the degreasing step (S130), degreasing Before the step (S130) it is possible to prevent the rust on the metal component.

In other words, in this embodiment, the metal parts are degreased using an alkali degreaser rather than a solvent degreaser. However, at this time, the cleaning power of the alkaline degreasing agent may be somewhat inferior to the solvent-based degreasing agent. In this case, by first removing the residual oil in the hot water washing step (S120), degreasing can be made sufficiently. In this hot water washing step (S120), when foreign matter such as iron is attached to the surface of the metal part, such foreign matter is also removed first.

On the other hand, in the process of hot water washing the metal parts by the hot water washing step (S120), the water used for hot water and the oil separated from the metal parts are mixed to generate the flowing water, water is preferably recycled from the generated water. To this end, in the present embodiment, after separating the oil and water from the running water generated during the hot water washing process, the separated oil is discarded, and re-supplying the separated water to the hot water washing step (S120) (S125). It may include.

In this way, after the water is separated and circulated and resupplyed, it is possible not only to increase the replacement cycle of the water supplied to the hot water washing step (S120), but also to separate the oil separated from the metal parts.

After the metal part is wet, the surface of the wet metal part is degreased (S130). In this embodiment, an alkali degreasing agent is used for degreasing. At this time, the alkaline degreasing agent used in the liquid is dissolved in water.

The alkali degreasing agent may contain a surfactant and an alkali generating agent as main components. Here, it is preferable that surfactant is used that is excellent in the emulsification effect of mixing water and oil, and can prevent re-adhesion of oil components on the surface of metal parts. For example, the alkali degreasing agent is 15-25 mass% potassium silicate, 1-10 mass% free potassium phosphate, 1-10 mass% ethylediamine tetraacetic acid, 1-5 mass% ethoxylated nonylphenol, 1 -5% by mass of hydroxy potassium and the remaining amount of water can be included. The alkali degreasing agent thus formed is used in a diluted state with further water added.

Since the alkaline degreasing agent for degreasing can use water as a solvent, it is possible to discharge the water used as the solvent harmlessly to the environment, compared to disposing of the organic solvent used as the solvent in the solvent-based degreasing agent, solvent-based degreasing agent Odor problems due to volatilization of organic solvents can be reduced. In addition, the alkali degreasing agent can reduce the problem of corrosive metal parts during degreasing compared to solvent-based degreasing agents. As the solvent of the alkali degreasing agent, water is used similarly to the solvent of the phosphate coating agent described later, so that the surface of the degreased metal part is made hydrophilic. Accordingly, as will be described later with reference to FIG. 4, a dense crystal shape can be obtained by improving crystal growth during formation of the phosphate film.

The degreasing step S130 may be performed by at least two degreasing steps S131 and S132 to sufficiently degrease the surface of the metal component.

In the process of degreasing the metal parts by the degreasing step (S130), a mixture of the liquid alkaline degreasing agent used for degreasing and the oil and debris removed from the metal parts is generated, and the alkaline degreasing agent is recycled from the mixture. desirable.

To this end, in this embodiment, the oil and debris and the alkaline degreasing agent are separated from the mixture generated during the degreasing process, and then the separated oil and debris are disposed of, and the separated alkaline degreasing agent is supplied to the degreasing step (S130) or When the degreasing step (S130) is performed in two or more degreasing steps (S131, S132), resupplying the alkaline degreasing agent separated from the mixture generated in the degreasing step in each degreasing step to different degreasing steps ( S135) may be further included.

Here, to be described in the case where the degreasing step (S130) is performed in two degreasing steps (S131, S132), in the preceding degreasing step (S131), oil and debris and alkali degreasing agent from the mixture overflowed in the process of degreasing After separation, the separated oil and debris are disposed of, and the separated alkali degreasing agent is supplied to a subsequent degreasing step (S132), and in the subsequent degreasing step (S132) receiving the alkali degreasing agent, alkali overflowed during the degreasing process. By supplying the degreasing agent to the preceding degreasing step (S131), the alkaline degreasing agent can be circulated, as indicated by the dashed arrows.

If the alkaline degreasing agent is circulated continuously, the replacement cycle of the alkaline degreasing agent supplied to the degreasing step (S130) may be increased, and the oil and the residue separated from the metal parts may be disposed of separately. . On the other hand, in the degreasing step (S130), it is also possible to enhance the degreasing effect by degreasing by the air bubble generator or the ultrasonic generator.

After the metal parts are degreased, the degreased metal parts are washed with water (S140). Here, water washing is a process of washing the metal parts with water, and after the metal parts are degreased, an alkali degreaser is adsorbed onto the surface of the metal parts to remove the alkali degreasers. If the layer is formed, the formation of the phosphate film, which will be described later, may be hindered, thereby making it possible to remove the alkali degreasing agent layer from the surface of the metal part. The washing step (S140) may be performed at least two times to effectively remove the alkali degreasing agent layer.

After washing the metal parts, a phosphate film is formed on the surface of the washed metal parts (S150). Here, the phosphate coating is formed of a phosphate coating, which is a liquid phosphate coating dissolved in water.

The phosphate coating agent is preferably used to improve the corrosion resistance and to improve the adhesion during coating. Conventional phosphate coatings may be used, for example, phosphate coatings include zinc dihydrogen phosphate, phosphoric acid, zinc nitrate, sodium nitrite, and the rest. It may be made of a composition comprising water. Forming such a phosphate film (S150) may be performed at least two times to effectively form a phosphate film.

On the other hand, the phosphate sludge is generated in the step of forming the phosphate film (S150), it is preferable that the phosphate sludge is recovered or reused so as not to cause environmental pollution. To this end, the present embodiment may further include the step (S155) of depositing and removing the phosphate sludge generated in the process of forming the phosphate film.

After the phosphate film is formed on the surface of the metal part, the metal part on which the phosphate film is formed is washed with water (S160). Here, since the phosphate film is formed on the surface of the metal part after the phosphate film is formed on the surface of the metal part, This can be removed. The washing step (S160) may be performed at least twice to effectively remove the phosphate coating agent remaining on the surface of the metal part.

After washing the metal parts, the washed metal parts are dried and then discharged (S170). Then, the metal part with the phosphate treatment on the surface can be finally obtained.

When the phosphate film is formed on the metal surface by the phosphate treatment method as described above, the phosphate crystal as shown in FIG. 4 can be obtained, which is compared with the conventional phosphate film shown in FIG. same. Here, the same phosphate coating agent was used, respectively.

As shown in FIG. 4, it can be seen that the shape of the phosphate crystal has a dense structure unlike the conventional phosphate crystal shown in FIG. 2. That is, the shape of the phosphate crystal according to the present invention is generally composed of a spherical structure (sphere), and thus can be more robust to bending or external impact than in the prior art.

In addition, since the anchoring effect with the adhesive at the time of painting can be improved as compared with the prior art, the adhesiveness at the time of coating can be improved. In addition, since the size of the phosphate crystal is fine, the surface area relative to the weight of the phosphate film is larger than in the prior art, and thus it can be confirmed that the adhesion may be increased during coating.

According to the present invention as described above, by using an alkali degreasing agent to degrease the metal parts, it can be environmentally friendly compared to the solvent-based degreasing agent, the odor problem can be solved.

In addition, compared with the solvent-based degreasing agent, it is possible to reduce the problem of corroding metal parts during degreasing.

In addition, since the surface of the metal part degreased by the alkali degreasing agent has hydrophilicity, when the phosphate coating is formed using the phosphate coating agent using water as a solvent, the crystal growth can be improved and a dense crystal shape can be obtained.

Therefore, by increasing the surface area relative to the weight of the phosphate coating, there is an effect that the adhesion can be improved during coating.

Although the present invention has been described with reference to one embodiment shown in the accompanying drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Could be. Accordingly, the true scope of protection of the invention should be defined only by the appended claims.

Claims (11)

delete delete delete delete delete delete Injecting metal parts; Washing the injected metal parts; 15-25 mass% potassium silicate, 1-10 mass% free potassium phosphate, 1-10 mass% ethyledamine tetraacetic acid, 1-5 mass% ethoxylated nonylphenol, 1- Degreasing the surface of the heated metal part with an alkali degreasing agent comprising 5% by mass of hydroxy potassium and the remaining amount of water; Washing the degreased metal parts; Forming a phosphate coating on the surface of the washed metal part; And And washing, drying, and discharging the metal component having the phosphate film formed thereon. The method of claim 7, wherein Separating water from the oil and water mixed with the oil generated in the process of washing the metal parts by the step of hot water, and then re-supply the separated water in the step of hot water Phosphate treatment method. The method of claim 8, The degreasing step is a phosphate treatment method of a metal part, characterized in that performed at least two times. The method of claim 9, By separating the alkali degreasing agent from the mixture of the liquid degreasing agent and oil of the liquid generated in the process of degreasing the surface of the metal parts by the degreasing step, and then supply the separated alkali degreaser, or resupply in another degreasing step And circulating an alkali degreasing agent. The method of claim 7, wherein The method of claim 2, further comprising the step of precipitating and removing the phosphate sludge generated in the step of forming the phosphate film.

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