Color-Coated Steel Sheet

Color-coated steel sheet, also known as colored coated steel sheet or pre-coated steel sheet, is a composite material made by coating or laminating various organic coatings or plastic films on the surface of metal coils (such as cold-rolled steel sheets, hot-dip galvanized steel sheets, aluminum-coated steel sheets, high-aluminum alloy sheets, stainless steel sheets, etc.) as the base material.

To provide protection, insulation, and decorative effects. The coating forms a dry protective film on the surface of the material, thereby endowing the base with properties such as resistance to atmospheric corrosion, pollution, and aging, while enhancing its aesthetics, including color, luster, texture, and more.

Color-coated steel sheets combine the advantages of both organic polymers and steel sheets. They not only possess the excellent colorability, formability, corrosion resistance, and decorativeness of organic polymers but also have the high strength and easy processability of steel sheets. They can be easily processed through operations such as blanking, bending, deep drawing, and welding.

a) Classification by base material: Cold-rolled steel sheet, hot-dip galvanized steel sheet, electro-galvanized steel sheet, alloyed steel sheet, galvanized-aluminum steel sheet, electro-galvanized alloy steel sheet, tin-plated steel sheet, chrome-plated steel sheet, aluminum sheet, etc.

b) Classification by processing technology: Organic coated steel sheets manufactured by methods such as roll coating, spray coating, powder coating, film lamination, and printing.

c) Classification by number of coating applications: One-coat one-bake, two-coat two-bake, three-coat three-bake, etc.

d) Classification by pattern: Wood-grain sheet, marble-pattern sheet, pearl-pattern sheet, suede-pattern sheet, metallic-effect pattern sheet, cement mortar-pattern sheet, etc.

e) Classification by coating type: Polyester (PE), high-durability polyester (HDP), silicone-modified polyester (SMP), polyvinyl chloride (PVC), polyurethane coating (PU), epoxy resin coating (EP), fluorocarbon coating (PV [Note: The original text is incomplete; the full name is usually Polyvinylidene Fluoride (PVDF) for fluorocarbon coatings]).

a) Inlet section: Equipped with equipment such as uncoilers, edge trimmers, seam welders, and accumulator loops. Its function is to unroll the raw material coils and connect them, so as to continuously supply metal sheets to the production line at a uniform speed.

b) Pretreatment section: Cleans the steel sheet to be coated and performs surface treatment to improve corrosion resistance and the adhesion of the paint film.

c) Coating section: The core part of the entire production line. It usually adopts a two-coat two-bake process where both the front and back sides are coated simultaneously, i.e., primer coating (initial coating) → baking and curing → cooling → topcoat coating (finish coating) → baking and curing → cooling. Depending on product requirements, it can also adopt a one-coat one-bake process or coat only one side. During painting, reverse or forward roll coating can be used. The oven temperature is controlled in sections, and the temperature of each section depends on the type of coating used, the thickness of the base sheet, and the time it takes to pass through the oven.

d) Outlet section: Slits the finished product into coils (or cuts it into individual coils of the required size).

Uncoiling → Seam welding → Inlet accumulator loop → Cleaning → Pretreatment → Initial (finish) coating → Initial (finish) curing → Cooling → Outlet accumulator loop → Cutting → Coiling.

Color-coated steel sheets are widely used in multiple fields:a) Construction industry: Used for the decoration and protection of exterior walls and roofs, providing an attractive appearance and durability.

b) Home appliance industry: Used in the manufacturing of home appliance casings, providing corrosion resistance and an aesthetic surface finish.

c) Decoration industry: Widely used in indoor and outdoor decoration.

d) Temporary construction industry: Used in the construction of temporary enclosures, temporary office spaces (prefabricated houses), and the construction of emergency sites (mobile cabin hospitals), etc.