JP2019031701A - Hot dip galvanizing method - Google Patents

Abstract

An object of the present invention is to eliminate the process of removing plating adhered to a tool, reduce labor, and improve the durability of the tool.
For a tool, a pretreatment for sequentially performing a degreasing process, a pickling process, and a flux process is omitted. By omitting this step, adhesion of the plating solution to the tool can be prevented. Moreover, since the plating solution does not adhere, the process of removing the plating from the tool can be omitted. Since the treatment liquid for removing the plating uses hydrochloric acid and sulfuric acid, the deterioration of the tool can be prevented by omitting the plating removal treatment.
[Selection] Figure 1

Description

  The present invention provides a hot dip galvanizing method that can omit the step of removing the plating adhering to the tool and enhance the durability of the tool in a method of performing hot dip galvanizing treatment by supporting a workpiece on a tool. About.

  2. Description of the Related Art Conventionally, a hot dip galvanizing method is known in which a workpiece is plated stepwise by immersing the workpiece in a plurality of different plating baths. For example, Patent Document 1 describes a hot-dip plating method in which a “second plating step” in which a work is immersed in a molten zinc-aluminum alloy bath is performed after a “first plating step” in which the work is immersed in a hot-dip zinc bath. Has been.

JP 2003-155548 A

  By the way, in the hot dipping method of Patent Document 1, in order to prevent the aluminum component from being mixed into the hot zinc bath, when the hanger (tool) used in the second plating step is reused, the zinc adhering to the tool is used. And a step of removing zinc alloy (plating).

  However, when the step of removing the plating is performed, there is a problem that it takes time and effort. Further, when hydrochloric acid or sulfuric acid is used for the tool to remove the plating, there is a problem that the tool is damaged early and its life is shortened.

  Therefore, an object of the present invention is to provide a hot dip galvanizing method that can save the trouble of removing the plating from the tool, suppress the waste of the metal material for plating, and increase the durability of the tool. is there.

  In order to solve the above-described problems, the hot dip galvanizing method of the present invention includes a pretreatment step for performing a pretreatment for removing deposits from a workpiece, and plating for immersing the workpiece from which deposits are removed in a plating bath. And in the plating process, the pretreated workpiece is supported by a non-pretreated tool and immersed in a plating bath.

  In the plating step, the workpiece may be immersed in a plurality of plating baths. For example, the workpiece may be immersed in a first plating bath for storing molten zinc and a second plating bath for storing a molten zinc-aluminum alloy containing aluminum and magnesium.

  The hot dip galvanizing method of the present invention may include a step of performing a regeneration process for bringing the tool closer to a state in which the tool is not pretreated. Specifically, a regeneration process for forming an oxide film on the surface of the tool after being used in the plating step can be performed.

  Further, the tool may be subjected to a surface treatment to form a passive film. The passive film includes, for example, a film made of ceramic or black rust.

  The shape of the tool may be a shape that is supported so that the workpieces do not come into contact with each other and the plating can be sufficiently in contact with the entire surface of the workpiece. Can be preferably used. Further, a centrifugal tool that supports a plurality of workpieces such as bolts on a concentric circle can also be preferably used.

  According to the hot dip galvanizing method of the present invention, since the pretreatment is not performed on the tool, it is possible to prevent the plating from adhering to the tool. For this reason, the tool can be reused as it is, and the trouble of removing the plating from the tool can be saved, and the waste of the metal material for plating can be suppressed.

  Moreover, since the adhesion of the plating to the tool is prevented, the deterioration of the tool due to hydrochloric acid or the like used for removing the plating can be prevented, and the durability of the tool can be enhanced.

It is a flowchart of the hot dip galvanization processing method which shows one Embodiment of this invention. It is a perspective view which shows the centrifugal tool which can be used for the plating method of FIG. It is a perspective view which shows the porous tool which can be used for the plating method of FIG.

  Hereinafter, the hot dip galvanizing method according to the present invention will be described with reference to the drawings. As shown in FIG. 1, the hot dip galvanizing method 1 of this embodiment is a hot dip aluminum alloy plating method, which mainly comprises a pretreatment step 2 and a plating step 3, and before and after the plating step 3, A step S4 for setting W1 to the tool 21 and a step S7 for taking out the workpiece W1 from the tool 21 are provided.

  In the pretreatment step 2, pretreatment such as removal of dirt, rust, dust and other adhering matter attached to the surface of the workpiece W1 is performed. Typical pretreatments include degreasing treatment S1 for removing oils and fats on the workpiece surface, pickling treatment S2 for removing oxidizing substances such as rust, and flux treatment S3 for processing the workpiece surface so as to be familiar with plating. These processes are performed by immersing the workpiece W1 accommodated in the punching container 11 in each processing solution.

  The plating step 3 includes a one-bath plating process S5 in which the workpiece W1 is immersed in a first plating bath for storing molten zinc, and a second plating bath in which a molten zinc-aluminum alloy containing aluminum and magnesium is stored. And bath plating treatment S6.

  As shown in FIG. 2, the tool 21 includes a number of workpiece storage cylinders 22. The work accommodating cylinder 22 is arranged and fixed by a frame 23 so as to be concentric with the axis 24 of the tool 21. In the plating step 3, the handle 25 connected to the tip of the shaft core 24 is suspended, and the tool 21 supporting the workpiece W1 is immersed in the first and second baths 26 for plating. After the plating, the tool 21 is taken out from the first and second baths 26, and the tool 21 is rotated around the shaft core 24 at a high speed. Excess metal for plating can be blown off from the workpiece surface by centrifugal force.

  Next, the hot dip galvanizing method 1 will be described in detail. First, in the pretreatment step 2 shown in FIG. 1, the punching container 11 containing a plurality of workpieces W1 (bolts are shown) is immersed in a degreasing treatment liquid tank, and degreasing treatment S1 is performed. When the degreasing process S1 is completed, the punching container 11 is pulled up from the processing liquid tank, and the workpiece W1 is washed with water.

  Subsequently, the punching container 11 containing the workpiece W1 is immersed in the pickling treatment liquid tank, and the pickling treatment S2 is performed. When the pickling process S2 is completed, the punching container 11 is pulled up from the processing liquid tank, and the work W1 is washed again with water.

  And the punching container 11 which accommodated the workpiece | work W1 is immersed in a flux processing liquid tank, and flux processing S3 is implemented. When the flux process S3 is completed, the punching container 11 is pulled up from the processing liquid tank.

  When the preprocessing step 2 is completed, the workpiece W1 is set in the workpiece accommodating cylinder 22 of the tool 21 (S4). At this time, the tool 21 that has not been pretreated is used.

  Next, the tool 21 supporting the workpiece W1 is immersed in the plating first bath 26, and the one bath plating process S5 is performed. After plating the surface of the workpiece W1, the tool 21 is lifted from the plating first bath 26.

  When the one-bath plating process S5 is completed, the tool 21 supporting the workpiece W1 is immersed in the second plating bath 26, and the two-bath plating process S6 is performed. After plating the surface of the workpiece W1, the tool 21 is lifted from the plating second bath 26. Thereafter, the tool 21 is rotated to sufficiently shake off the surplus metal of the plating remaining on the surface of the work W1.

  When the plating step 3 is completed, the workpiece W1 is taken out from the tool 21 (S7), and the workpiece W1 is water-cooled. Thereafter, the tool 21 used for the plating process can be used repeatedly by setting the workpiece W1 that has completed the pretreatment step 2 in the next plating process without performing the process of removing the plating.

  According to the hot dip galvanizing treatment method 1 having the above configuration, only the workpiece W1 is pretreated and the tool 21 is not pretreated, so that a state in which the tool 21 is not familiar with the plating is maintained and adhesion of the plating to the tool 21 is prevented. can do. For this reason, the process which removes plating from the tool 21 can be skipped, and there is an excellent effect that labor can be saved.

  Moreover, since the adhesion of the plating to the tool 21 can be prevented, a treatment liquid such as hydrochloric acid for removing the plating is not required, the deterioration of the tool 21 due to the treatment liquid can be prevented, and the life of the tool 21 can be extended. In addition, the consumption of metal materials such as zinc, aluminum, and magnesium can be reduced.

  In the hot dip galvanizing method 1 of the above embodiment, the tool 21 can be reused after being regenerated. Specifically, in the regeneration process, first, the pickling process S2 is performed on the tool 21, and the tool 21 is washed with water. Next, after performing the degreasing treatment S <b> 1, the tool 21 is heated and baked to form an oxide film on the surface of the tool 21. Then, after performing the regeneration process, the work W1 is set on the tool 21, and the tool 21 is immersed in the first and second plating baths 26 together with the work W1. If it carries out like this, plating will become difficult to adhere to the tool 21 with the oxide film formed in the tool 21.

  Furthermore, in the hot dip galvanizing method 1 of the above embodiment, the tool 21 having a passive film formed on the surface can also be used. As the passive film, a material to which plating is difficult to adhere, for example, a film generated by ceramic processing or black rust processing is preferable.

  Next, a modified example of the tool will be described. A tool 31 shown in FIG. 3 includes a skewer member 32 and a porous plate 33. An annular workpiece W2 such as a washer is inserted through the skewer bar 35 of the skewer member 32, and a part of each workpiece W2 is fitted into the opening 34 of the plate 33 and positioned. According to the tool 31, there is an effect that a large number of workpieces W2 can be supported without being in contact with each other with a predetermined interval.

  The present invention is not limited to the hot dip zinc aluminum alloy plating method of the above embodiment, and can be carried out by appropriately changing the configuration and procedure of each part without departing from the spirit of the invention. is there.

DESCRIPTION OF SYMBOLS 1 Hot-dip galvanization processing method 2 Pre-processing process 3 Plating process 11 Punching container 21, 31 Tool 22 Work accommodating cylinder 23 Frame 24 Shaft core 25 Handle 26 Plating first bath, plating second bath 32 Skewer member 33 Porous plate 34 Opening 35 Skewer W1, W2 Workpiece

Claims (4)

A pretreatment step for performing a pretreatment for removing deposits from the workpiece, and a plating second for storing a molten zinc alloy after the workpiece from which the deposits have been removed is immersed in a first plating bath for storing molten zinc A plating step of immersing in a bath,
In the plating step, the hot-dip galvanizing method is characterized in that the pretreated workpiece is supported by a non-pretreated tool and immersed in the first plating bath.   The hot dip galvanizing method according to claim 1, wherein the second plating bath stores a hot dip galvanized aluminum alloy containing aluminum and magnesium.   The hot dip galvanizing method according to claim 1, wherein the tool after use in the plating step is subjected to a regeneration process, and an oxide film is formed on the tool surface by the regeneration process.   The hot dip galvanizing method according to claim 1 or 2, wherein a tool having a passive film formed on a surface thereof is used in the plating step.

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