Galvanizing process

Galvanizing process

1. Electric galvanizing process

Taking galvanized iron alloy as an example, the process flow is as follows:

Chemical oil removal → hot water washing → water washing → electric oil removal → hot water washing → water washing → strong corrosion → water washing → electric galvanized iron alloy → water washing → light out → passivation → water washing → dry.

2, electrogalvanizing plating solution preparation

Preparation of plating solution (take lL as an example) :

(1) Add 1/3 volume of pure water into the plating tank;

(2) Use 1/3 pure water to dissolve sodium hydroxide (it will be hot when dissolved, must be careful);

(3) Adjust zinc oxide into paste with a small amount of water, and then add more pure water, stir fully. The stirred zinc oxide is slowly added to the dissolved sodium hydroxide solution, adding side by side stirring, so that it is fully complexed and added to the plating tank;

(4) When the bath temperature drops below 30℃, add 85g Baser and stir thoroughly;

(5) Dissolve 15mL BaseF in 15g BaseR, and then add its mixture to the plating bath;

(6) Add 4mL H-0624 and stir thoroughly; Add water to the assigned volume;

(7) Add brighteners ZF-105A and ZF-105B; Stir well.

Black passivation process: water washing → light out → water washing → black passivation → water washing → post-treatment → drying.

3. Influencing factors of electric galvanizing

(1) The influence of zinc content

Zinc content is too high, the brightness range is narrow, easy to obtain thick coating, coating iron content is reduced; The zinc content is too low, the brightness range is wide, it takes a long time to reach the required thickness, and the plating has high iron content.

(2) The influence of sodium hydroxide

When sodium hydroxide content is too high, high temperature operation is easy to burn; When sodium hydroxide content is too low, the dispersion ability is poor.

(3) The influence of iron content

The iron content is too high, the iron content in the coating is high, the passivation film is not bright; The iron content is too low, the iron content in the coating is low, the corrosion resistance is reduced, and the color is olive.

(4) The influence of brightener

ZF-100A is too high, and the coating is brittle. Too low, low current area without coating, passivation color is uneven; If ZF-100b is too high, the coating is brittle. Too low and the entire coating will not shine.

(5) The influence of temperature

The temperature is too high, the dispersion ability is reduced, the iron content in the coating is high, the corrosion resistance is reduced, the color of the passivation film is not uniform, and the hair is flower; The temperature is too low, the high current density area is scorched, the coating is brittle and the deposition speed is slow.

(6) The influence of cathode movement

Cathode movement must be used. Moving too fast, high current density area coating rough; Too slow, may produce airflow, local no coating.