How to Process and Electroplate the Galvanized Rectangular Tube?

Galvanized rectangular tube processing is based on the principle of electrolysis. Through the electrolysis process of metal ions, a layer of metal or alloy is deposited on the surface of rectangular tube to change the physical and chemical properties of the rectangular tube surface, and finally make the galvanized sheet have wear resistance, decoration and impact resistance, etc,. In addition, according to the special requirements of the rectangular tube, it can be coated with a specific coating, such as light energy and electromagnetic coating, etc., which can fully expand the application field of galvanized rectangular tube.

The processing and electroplating process of galvanized rectangular tube mainly includes pretreatment, electroplating and post-plating treatment. The quality of the coating depends on the electroplating process of the material, and the electroplating process is affected by many factors, mainly including the following six aspects:

1. Zinc content

The higher the zinc purity of the zinc block, the narrower its bright range, the easier it is for the rectangular tube to obtain a thicker coating, and the lower the iron content in the coating; when the purity of the zinc block is too low, its bright range will be wider. The specified thickness of the zinc layer takes longer, which results in a higher iron content in the zinc layer.

2. Sodium hydroxide

Sodium hydroxide has a dual effect on the reaction. When its content is too high, scorching is easy to occur during high-temperature operation; and when its content is too low, the solution dispersibility is poor, which will reduce the quality of the zinc layer.

3. Iron content

When the iron content is too high, the iron in the coating of the rectangular tube will be correspondingly large, which will lead to insufficient brightness of the passivation film of the rectangular tube; while the iron content is too low, the iron content in the galvanized layer will be low, and the resistance of the rectangular tube will be reduced. Corrosive, and will cause the surface of the rectangular tube to be olive-colored.

4. Brightener

More brighteners are now used by mixing ZF-100A and ZF-100B. If the concentration of the former is too high, the brittleness of the rectangular tube coating will be enhanced, while too low a concentration will cause the coating in the low-current area to be sparse, resulting in uneven passivation.

5. Temperature

If the temperature is too high during the electroplating process, the dispersibility of the solution will decrease, the iron content in the coating of the rectangular tube will increase, and the passivation will be uneven; when the reaction temperature is too low, the high current density area will be easily scorched, and the coating of the rectangular tube will be more brittle. And the deposition rate is slow.

6. Cathode moving speed

During the electroplating process, it is necessary to ensure that the cathode is in a moving state. If the moving speed is too fast, the coating in the high current density area during the electroplating process will be rough; if the moving speed is too slow, airflow may be generated, resulting in uneven coating of the rectangular tube.

The galvanized rectangular tube uses zinc as the electroplating metal, electrolyzes Zn2+ in the solution, and then deposits it on the surface of the galvanized rectangular tube to form a uniform and dense zinc metal layer. Compared with other metals, zinc is an amphoteric metal, which is easily soluble in acid and alkali, and it is easier to electrolyze metal ions in solution. During the processing of galvanized rectangular pipe, attention should be paid to the above aspects in order to produce high-quality qualified galvanized rectangular pipe products.

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