GI Sheet

GI sheet refers to a steel plate that is coated with a layer of zinc on its surface for aesthetic and rust prevention purposes. The main method for surface galvanizing of steel plates nowadays is hot-dip galvanizing, which has a much higher corrosion resistance than electrogalvanizing. hot-dip galvanizing will not rust for several years, while electrogalvanizing will rust within six months. GI sheets have excellent corrosion resistance in dry or pollution-free environments. But in polluted environments, the lifespan will be greatly shortened, so pre coating treatment is necessary.

In general, the corrosion of GI sheets does not mean that the galvanized layer on the surface is uniformly corroded off, but rather that it is first corroded off in areas where the coating and steel substrate are poorly bonded, resulting in localized severe corrosion and loss of performance. From this perspective, the adhesion of the galvanized layer, especially the overall adhesion, is more important than the thickness of the galvanized layer. If the local adhesion of the galvanized layer is poor, even if the galvanized layer is thick, it will start to rust from the poor adhesion. This is similar to the "bucket principle", which is a problem that steel galvanizing production technicians must understand. The production process of GI sheet mainly includes: raw material preparation → pre plating treatment → hot dip coating → post plating treatment → finished product inspection, etc. According to tradition, hot-dip galvanizing processes are often divided into two categories based on different pre-treatment methods: offline annealing and online annealing, namely:
Wet method (hot-dip galvanizing method for single steel plate)
Hot dip galvanizing method for single steel plate after offline annealing
Wheeling method for hot-dip galvanizing (continuous hot-dip galvanizing method for strip steel)
In line annealing Sendzimir method (shielding gas method) improved Sendzimir method
American Steel Union Method (same as Kawasaki Method in Japan)
Selas method
Sharon method

The purpose of GI sheet
GI sheet is mainly used in industries such as construction, home appliances, automobiles, mechanical electronics, and light industry.

Galvanized Steel Coil /GI Coil Strips/GI Sheet❗️❗️❗️