The principle of hot-dip galvanizing, simply put, is to clean the cleaned iron, through the Flux wetting effect, immersed in the zinc bath, the steel and molten zinc react to form an alloying film.
Good hot-dip galvanizing operations, the process should be under strict control, and fully play the function of the process. And if the previous process is not good, will cause the chain reaction of the subsequent process, and a substantial increase in operating costs or causing hot dip galvanized defective products. If the pre-treatment is not good, then the molten zinc can not be completely normal with steel to form the perfect zinc coating. If the post-processing is not good, it is easy to undermine the appearance of galvanized layer, reducing the value of galvanized goods.
■ Below a detailed description of the process
Remove surface impurities such as oil on the item to be galvanized. Operation temperature 65°C to 85°C
Remove steel rust with hydrochloric / sulfur acid (Room temperature)
Immersive into zinc/ammonia chloride solution to prevent steel to re-oxide and increase reaction speed of zinc and steel; operation temperature at 60°C to 80°C
Operators remove furnace surface ash / zinc oxide to ensure quality appearance
Sent to water tank for cooling; operation temperature about 60°C
Surface check and coating thickness measurement to ensure quality.