How Do I Choose the Best Paint for Galvanized Metal?

Galvanized sheet steel refers to metal substrates that are galvanized on both sides of the cold-rolled steel sheet. It can be directly made into paint buckets or other metal containers, and it can also be used for decorative panels. A zinc-plated coating is a colored zinc plate. The wall decoration generally uses galvanized iron plates above 183g / m ² , while the roof decoration generally uses galvanized iron plates above 244g / m ² . In addition, there is another type of thin steel plate without any other metal-plated cloth. The specifications and dimensions are similar to those of tin-plated steel plate. Its basic property is the characteristics of the steel substrate of the tin-plated steel plate. In the production of iron printing, this kind of plate is suitable for miscellaneous can bodies, lids, thermos bottle shells, and signage products that are covered with paint on the front and back, and is also often used as the base material for coated iron. ^[1]

The galvanized steel sheet is formed by coating a zinc protective layer with a thickness of 0.02 mm or more on the surface of the pickled steel sheet. The thickness of galvanized sheet is 0.44 ~ 1mm. Its structure is shown below.

According to production and processing methods can be divided into the following categories:

Hot-dip galvanized steel. The steel sheet is immersed in a molten zinc bath, and a layer of zinc steel sheet is adhered to the surface. At present, it is mainly produced by continuous galvanizing process, that is, the coiled steel sheet is continuously immersed in a zinc plating bath with molten zinc to make a galvanized steel sheet;

Galvanized steel sheet. This steel plate is also manufactured by the hot dipping method, but immediately after it is out of the tank, it is heated to about 500 ° C to make it an alloy coating of zinc and iron. This galvanized sheet has good paint adhesion and weldability;

Galvanized steel sheet. The galvanized steel sheet produced by electroplating has good workability. But the coating is thin, and the corrosion resistance is not as good as the hot-dip galvanized sheet;

Single-side and double-side differential galvanized steel. Single-sided galvanized steel, that is, products with only one side galvanized. In welding, painting, anti-rust treatment, processing, etc., it has better adaptability than double-sided galvanized sheet. In order to overcome the shortcomings of uncoated zinc on one side, there is another type of galvanized sheet coated with a thin layer of zinc on the other side, that is, a double-sided differential galvanized sheet;

Alloy and composite galvanized steel sheet. It is made of zinc and other metals such as lead, zinc, and even plated steel. This steel plate has both excellent anti-rust performance and good coating performance.

In addition to the above five types, there are color galvanized steel sheets, printed coated galvanized steel sheets, and polyvinyl chloride laminated galvanized steel sheets. But currently the most commonly used is hot-dip galvanized sheet.

Galvanized steel sheet can be divided into general use, house use, building exterior board use, structure, tile board use, drawing and deep drawing etc.

Major domestic production plants: Baosteel, Hebei Iron and Steel, Wuhan, Angang, Shougang, etc .;

The major foreign producers are Japan, South Korea, Germany, Russia, and France.

(1) Surface state: Due to the different treatment methods in the galvanized sheet, the surface state is also different, such as ordinary zinc flower, fine zinc flower, flat zinc flower, non-zinc flower, and phosphated surface. German standards also specify surface levels.

(2) The galvanized sheet shall have good appearance, and shall not have defects that are harmful to the use of the product, such as no plating, holes, cracks and scum, exceeding plating thickness, abrasion, chromic acid dirt, white rust, etc. Foreign standards are not very clear about specific appearance defects. Some specific defects should be stated in the contract when ordering.

The galvanized sheet steel should be stored in the warehouse, placed underneath, and stacked in different specifications. A small amount can be stored on the shelf. Galvanized sheet steel will produce water stains of white powder when it encounters water. It is very easy to damage the zinc layer when it encounters chemicals such as salt, saltpeter, ammonium chloride, etc. It should avoid contact with the above substances.

Galvanized sheet steel is generally not degreased or oiled. If rust is found, use a dry cloth to wipe off the rust ash, and it should be stored separately and used in advance.