What are the classifications of galvanized steel

Galvanized steel is classified based on the coating thickness and the method used for the galvanizing process. The two main classifications of galvanized steel are as follows:

1. Hot-Dip Galvanized Steel (HDG):Hot-dip galvanized steel is the most common type of galvanized steel. It involves immersing the steel in a molten zinc bath, which metallurgically bonds the zinc to the steel substrate. The zinc coating provides excellent corrosion protection to the underlying steel. HDG can be further classified based on the coating thickness:

   a. Regular Spangle: This refers to the typical spangled appearance of the zinc coating on the steel surface. The coating thickness ranges from a few micrometers to several tens of micrometers.

   b. Minimized/Zero Spangle: In this type, the spangled appearance is minimized or eliminated, resulting in a smoother surface finish. The coating thickness is similar to regular spangle galvanized steel.

   c. Thick/Heavy Coating: This classification refers to galvanized steel with a relatively thicker zinc coating. It is commonly used for applications requiring enhanced corrosion protection in harsh environments.

2. Electro-Galvanized Steel (EG):Electro-galvanized steel is produced by electroplating a thin layer of zinc onto the steel substrate. Unlike hot-dip galvanizing, which involves immersing the steel in molten zinc, electro-galvanizing uses an electrolytic process. The zinc coating in electro-galvanized steel is typically thinner than that of hot-dip galvanized steel, ranging from a few micrometers to around 25 micrometers. Electro-galvanized steel offers good surface appearance and is often used in applications where corrosion resistance is required but not at the same level as hot-dip galvanized steel.

These classifications help differentiate galvanized steel based on the thickness and method of zinc coating. The selection of the appropriate type of galvanized steel depends on the specific application requirements, including the desired level of corrosion protection, aesthetic appearance, and cost considerations.