Corrosion Resistance

Physical Protective Action

If Zn is exposed to the air as a reactive metal, it becomes zinc oxide by sharply reacting with oxygen and also forms a thin film of basic zinc carbonate by reacting with carbon dioxide. This thin film prevents rust from corrosive environment with good dense adhesion.

Corrosion Resistance in the air

The life of Galvanized Steel is proportional to the coating weight of Zn. For same coating weight, however, the life may be largely changed by the usage environment. The corrosion resistance of galvanized steel in a city or industrial area is just 25~40% compared to an unpolluted rural area. The interior life at the same area is longer 5-10 times than the exterior life.

Formability

Due to excellent adhesion of Zn and ultra-thin alloyed layer of Fe-Zn, flaking hardly does not occur even after drawing work. Its formability is very excellent as much as cold rolled steel plates and it is available for diverse works.

Paintability

Galvanized Steel is mostly used after final coating, and the corrosion resistance of painting products depends on the disk, pre-treatment before painting and a kind of paint and varnish.

Weldability

For it has better electric conductivity than iron, such good conductivity makes electric resistance on the contact surface of the steel plate small and heating value is also small.

It has the lower meting point than iron. So, Zn attaches to electrode when welding and such attachment causes low continuous weldability.

Its current density falls a little bit due to comparatively wide contact areas by welding force (electrode force).