Introduction to galvanizing

Galvanized steels are to prevent the surface of the steel sheet from corrosion and prolong its service life. A layer of metal zinc is coated on the surface of the steel sheet. This galvanized steel is called galvanized steel sheet or coil. 

Galvanizing is an economical and effective rust prevention method that is often used, and about half of the world's zinc production is used in this process. The coating of galvanized steel sheet has strong toughness, and the galvanized layer forms a special metallurgical structure, which can withstand mechanical damage during transportation and use. The surface of galvanized steel sheet has strong anti-oxidation ability, which can strengthen the anti-corrosion penetration ability of parts.

Packing and transportation

The standard seaworthy package includes waterproof kraft paper and plastic film inside and GI sheets outside. Then it is bound with steel strips. Below are some pictures for your reference.

Product application

Galvanized steel coil products are mainly used in construction, light industry, automobile, agriculture, animal husbandry, fishery and commercial industries. 

The construction industry is mainly used for the manufacture of anti-corrosion industrial and civil building roof panels, roof grids, etc. 

The light industry uses it to manufacture household appliance shell, civil chimney, kitchen utensils, etc., and the automobile industry is mainly used to manufacture corrosion resistant parts of cars. 

Agriculture, animal husbandry and fishery are mainly used as food storage and transportation, meat and aquatic products frozen processing equipment; Commercial mainly used as material storage and transportation, packaging tools, etc.

Manufacturing process

Galvanized steel is a carbon steel that has been coated with zinc. The most common method of zinc coating is the hot-dip process.

The hot-dip process consists of submerging the carbon steel into a molten zinc bath (approximately 680 degrees Fahrenheit). When the material is removed from the zinc bath and cooled a reaction to the oxygen in the air occurs. The reaction causes the zinc to become part of the steel (an iron-zinc alloy bond). The new surface finish appears to have a crystalline finish or spangled finish.

Continuous galvanizing applies the zinc coating to the surface of a continuous ribbon of steel (coil) as it passes through a zinc bath. The coil travels at speeds of approximately 600 feet per minute.

As the coil leaves the zinc bath it carries with it an extra layer of molten zinc. The extra zinc is removed with high pressure air (air knives) to create the desired thickness. The material is then allowed to cool and the spangled. finish is formed.

Continuous galvanizing allows for more precise control of the thickness and is typically used for steel products that have not yet been fabricated. As the coating thickness increases, the risk of losing some coating during fabrication or forming also increases.