JPH0686677B2 - Molten salt electrolytic plating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrolytic plating apparatus for steel products using molten salt as a plating bath liquid.

[Conventional technology]

Aluminum electrolytic plating using a molten salt as a solution has been conventionally known as a plating method for steel materials, but has not been practically used.

One of the reasons for this is that no suitable means for activating the surface of the steel material has been developed, but for this problem, the method previously proposed by the applicant, namely,
This was solved by the molten salt electrolytic plating method of steel, which is characterized in that the surface of the steel is activated by performing an anodic dissolution treatment on the steel prior to the electrolytic plating of the molten steel. Please refer to the specification of the patent application filed on December 5, 1986 under the heading "Salt electrolytic plating method".

However, in the above proposed method, the iron content eluted in the molten salt by the anodic dissolution of the steel material is accumulated in the solution as iron ions, and the solution containing the iron ions adheres to the steel material and the molten salt bath in the plating tank There was a problem in that when iron particles were brought into the solution and the iron ions in the plating solution were increased, and when the iron ions in the plating solution increased, iron was mixed into the plating film on the steel and the quality of the plating film deteriorated.

Therefore, in order to eliminate the drawbacks of the proposed method, the present applicants
On the same date as the present invention, under the title of molten salt electrolytic plating method, a molten salt electrolytic plating method for steel material, in which a steel material is anodically dissolved in a molten salt bath and its surface is activated, is combined with a pretreatment operation. Proposed a molten salt electrolytic plating method characterized in that iron ions produced by anodic dissolution of steel are reduced by adding and mixing a metal having a higher ionization tendency than iron to precipitate as metallic iron.

[Problems to be solved by the invention]

However, the above-mentioned method applied for a patent on the same date as the present invention, since a metal having a higher ionization tendency than iron is added to the anodic dissolution bath solution of the steel material, there is iron precipitated in the bath solution, In addition to the deterioration of the steel, there is a problem that the iron is caught between the feed roller and the like when the steel material (for example, the steel strip) is conveyed and the surface of the steel material is damaged.

[Object of the Invention]

The present invention is intended to provide a molten salt electrolytic plating apparatus capable of solving the drawbacks of the above method filed on the same date as the present invention.

[Means for solving problems]

The present invention relates to a pretreatment tank for anodic dissolution of a steel material with a molten salt bath solution to activate the surface of the steel material, a molten salt electrolytic plating tank for plating the activated surface-treated steel material, and a bath solution of the pretreatment tank. A molten salt electrolytic plating apparatus comprising an iron ion removal tank filled with metal particles having a higher ionization tendency than iron, which communicates with iron.

That is, according to the present invention, as described above, the iron ions written in the bath liquid of the pretreatment tank are guided to the iron ion removal tank through an external system path, and the iron ions are brought into contact with metal particles having a higher ionization tendency than iron. Therefore, the bath liquid in the pretreatment tank is not deteriorated by iron and the steel material is not damaged.

The iron deposited in the iron ion removal tank is collected and separated by means such as a magnetic separator, and the iron-removed bath liquid is returned to the pretreatment tank again.

〔Example〕

An embodiment in which the present invention is applied to a continuous molten salt electrolytic plating apparatus for steel strip will be described with reference to FIG.

In FIG. 1, 1 is a steel strip, 2 is a plating tank, 2a is an anode melting tank which is a pretreatment tank, 3 is a plating tank anode plate, 3a is an anode melting tank cathode plate, 4 is a plating bath liquid, and 4a is an anode. Dissolving bath liquid, 5 and 5a are conductor rolls, 6 and 6a are deflector rolls, and 7 and 7a are DC power supplies (above 5-7, 5a-
7a is a member not related to a and a member related to the plating tank 2 and a numeral to which a is related to the anode dissolving tank 2a which is a pretreatment tank).

Further, 8 is a molten salt bath liquid circulation circuit, 9 is a pump, and 10 is an iron ion removing tank. In the iron ion removing tank 10, a packed layer 11 of metal (for example, aluminum) particles having a greater ionization tendency than iron. A screen 12 having finer mesh than the particles of the packed bed 11, a magnetic separator 13, and a screen 14 having finer mesh than the particles of the magnetic separator 13 are arranged.

As shown in FIG. 1, the steel strip 1 is subjected to degreasing, pickling and rinsing and drying treatment by a device (not shown), and then immersed in the anodic dissolution bath liquid 4a in the anodic dissolution tank 2a by the conductor roll 5a and the deflector roll 6a. Then, the conductor roll 5 and the deflector roll 6 immerse it in the plating bath liquid 4 in the plating tank 2 and lowers, raises, and winds it up on a take-up reel (not shown). Anode plate 3a and anode plate 3 are suspended in the anode melting tank 2a and facing the steel strip 1 in the plating tank 2. The positive side of the DC power supply 7a is the conductor roll 5a and the negative side is the cathode plate. 3a, the positive side of the DC power source 7 is connected to the anode plate 3, and the negative side is connected to the conductor roll 5, and an electric circuit is formed via the bath solutions 4a and 4, respectively.

If the steel strip 1 is continuously supplied to the tanks 2a and 2 and the electric circuit is energized, it is first anodically melted in the anodic melting tank 2a, the oxide film on the surface is removed and activated, and then the plating tank. In step 2, the plating process is performed to form a good quality coating film with good adhesion.

In the anodic dissolution tank 2a, the surface of the steel strip 1 is once melted and eluted as iron ions in the bath liquid 4a. If left as it is, bath liquid
Since iron ions in 4a increase, the bath liquid 4a is guided to the iron ion removing tank 10 by the pump 9 through the external circulation circuit 8,
Iron ions are removed and purified, and then returned to the anode dissolution tank 2a again.

Explaining the iron ion removing action, the iron ions are reduced to metallic iron powder by passing the bath liquid 4a through a packed bed 1 of metal particles (for example, aluminum) having a greater ionization tendency than iron, and the metal The iron powder is adsorbed, collected and separated by the magnetic separator 13. The separated bath liquid 4a 'is reinjected into the anodic dissolution tank 20 via the pump 12.

〔The invention's effect〕

According to the present invention, since the deterioration of the bath liquid of the pretreatment tank due to iron ions is prevented, the surface supplied to the plating tank is sufficiently activated, and a good quality coating film having excellent adhesion is stably formed. It

[Brief description of drawings]

FIG. 1 is a view for explaining an embodiment in which the present invention is applied to an apparatus for carrying out a continuous molten salt electrolytic plating method for steel strip.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI technical display location C25F 7/02 8414-4K (72) Inventor Kenichi Yanagi 4-6 Kannon Shinmachi, Nishi-ku, Hiroshima-shi, Hiroshima 22 Mitsubishi Heavy Industries Ltd. Hiroshima Works (72) Inventor Junkichi Yoneda 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City Hiroshima Prefecture Mitsubishi Heavy Industries Ltd. Hiroshima Works (72) Inventor Junichi Uchida Nishi Nagasumoto, Amagasaki City, Hyogo Prefecture Sumitomo Metal Industries, Ltd. General Technical Research Institute (72) Inventor Hirohisa Seto 1-3, Nishi-Nagasumoto, Amagasaki, Hyogo Prefecture Sumitomo Metal Industrial Co., Ltd. (72) Inventor Hirotaka Hayashi Sumitomo Metal Industries, Ltd. 5-15 Kitahama, Higashi-ku, Osaka-shi, Osaka

Claims (1)

[Claims] 1. A pretreatment tank for anodic dissolution of a steel material in a molten salt bath liquid to activate the surface of the steel material, a molten salt electrolytic plating tank for plating the activated surface-treated steel material, and a bath of the pretreatment tank. A molten salt electrolytic plating device comprising an iron ion removing tank filled with metal particles having a higher ionization tendency than iron, which is in communication with a liquid.