Hot rolled coil is produced via continuous casting process of slabs. This is the base material for cold rolled coil and coated coil, but can also be used directly into industrial applications such as steel tubes, construction, shipbuilding, gas containers, pressure vessels and energy pipelines.
Cold rolled coils have received an additional treatment after it has been hot rolled, pickled and oiled. The coils are moved into a series of rollers to lower its thicknesses and to have uniform surface smoothness. The process is done at room temperature. Cold rolled coils can then be further annealed to soften the steel. These characteristics, depending on the end-use, change with the intensity of the annealing.
Passing cold rolled coil through a melted zinc bath, in order to coat the steel with a thin layer of zinc to provide corrosion resistance, is called hot dip galvanizing. It has many applications in construction/building, roofing, automotive parts, sections, profiled sheets, etc…
Pre-painted Galvanized steel is a Galvanized steel with a number of paint layers and treatments in a carefully controlled environment in a continuous coil coating line. Pre-painting can also be done on electrogalvanized coils and cold rolled coils depending on the end-use and application of the steel.
Elektrogalvanized coating is being used to protect coils against corrosion by putting a layer of zinc on the surface of the coils. The process involves electroplating. Running electricity through a zinc solution with a zinc anode and a steel conductor. The application is mainly used in car industry where some parts only need 1 side coated materials.