There are generally two materials for food metal cans, aluminum and tinplate. Aluminum cans are generally two-piece cans, and the surface is mostly passivated, mainly used for the packaging of carbonated beverages. Tinplate is made of tin-plated iron surface, and tinplate metal cans are mostly composed of three metal sheets of can body, can bottom and can lid, commonly known as three-piece cans. In contrast, metal cans made of tinplate usually add an organic polymer coating to the surface or weld for oxidation protection.
