Galvanized Steel Composite Panel is a composite materia […]
Galvanized Steel Composite Panel is a composite material formed by steel and zinc. Galvanized steel composite panel combines the advantages of the two materials. The composite material has the strength and plasticity of steel and has wide application in industrial fields such as buildings, household appliances and automobiles.
Protective effect of galvanized steel composite panel and galvanizing method:
In the atmosphere, the corrosion resistance of zinc is much weaker than that of steel. Under normal conditions, zinc takes precedence over steel in corrosion.
(1) Physical effect: The zinc coating on the surface of the steel plate blocks the contact between the steel plate and the external corrosive medium, thus preventing the steel plate from being corroded by the corrosive medium.
(2) electrochemical action: when the galvanized steel composite panel and the zinc plating layer are exposed to the corrosive medium environment at the same time (e.g. scratches and cuts on the galvanized layer), since the electrode potential of zinc (-076V) is lower than that of iron (-0.44V), zinc is anode and steel is the cathode, so zinc preferentially corrodes and protects the substrate, which is called the sacrificial anode protection effect of zinc. Electrode potential is the tendency that certain ions or atoms acquire electrons and are reduced.
Hot plating and electroplating are the two main processes of galvanized steel composite panel. The main processes of galvanized steel composite panel are:
Hot galvanizing: The melting point of steel and zinc is quite different. The melting point of pure iron is 1534℃, while the melting point of zinc is 419℃. The method of directly dipping the treated strip steel into molten zinc for galvanizing is called hot galvanizing.
Continuous hot galvanizing of strip steel: the production process of connecting steel coils, carrying out necessary pretreatment and annealing, and directly galvanizing strip steel through a zinc pot with molten zinc is called continuous hot galvanizing of strip steel.