The three have an upstream-downstream relationship of “raw material → semi-finished product → finished product”, centered on the processing chain of metal building materials:
1. Galvalume Steel Coils: As the basic raw material, they are cold-rolled/hot-rolled steel coils with a surface coated with an aluminum-zinc alloy layer. Their core function is to provide a corrosion-resistant base material, serving as the “substrate raw material” for color steel coils and metal stone-coated roofing tiles.
2. Color Steel Coils: As intermediate semi-finished products, they are made by subjecting galvalume steel coils (or ordinary galvanized steel coils) to degreasing, phosphating, and painting (color coating) on the surface. They can be directly used for factory walls/roofs and also act as the “panel substrate” for metal stone-coated roofing tiles.
3. Metal Stone-Coated Roofing Tiles: As end finished products, they are roof tiles made by compounding natural colored sand (sintered and bonded at high temperature) on the surface of color steel coils (or directly using galvalume steel coils as the base plate). They are final building materials applied to building roofs.
In simple terms: Galvalume steel coils → processed into color steel coils → further processed into metal stone-coated roofing tiles (some metal stone-coated roofing tiles can skip the color steel coil link and directly use galvalume steel coils as the base material). The three are products of different stages in the building material processing chain.