1. Definition:

GP Coil is a flat-rolled steel product that has been coated with zinc through a galvanization process. This zinc coating helps protect the steel from rust and corrosion, particularly in outdoor or humid environments. Unlike corrugated or color-coated galvanized products, GP Coils are "plain" and often used as raw materials for further fabrication.

2. Production Process of GP Coils:

• Hot Rolled Steel as Base Material: The base material for GP Coils is hot rolled steel, which is produced by rolling steel slabs or billets at high temperatures.

• Pickling and Cleaning: The hot rolled steel is cleaned through a pickling process to remove surface impurities such as rust, scale, and oxides.

• Galvanization: The cleaned steel is then coated with zinc using one of two primary methods:

  • Hot-Dip Galvanizing: The steel coil is dipped into a bath of molten zinc, which adheres to the surface and forms a protective coating.
  • Electro-Galvanizing: An electric current is used to apply zinc to the surface of the steel in a thin, uniform layer.

• Cooling and Inspection: After galvanization, the GP Coils are cooled, inspected for quality, and then wound into large coils for storage and transportation.

• Optional Skin-Passing or Temper Rolling: To improve the surface quality and mechanical properties, the GP Coil may undergo additional processes such as skin-passing or temper rolling, which involve light cold rolling to enhance flatness and surface smoothness.