Hot Dip Galvanizing is the process of applying a zinc coating to fabricated iron structure by immersing the structure in a bath consisting primarily of molten zinc. The galvanizing prevents the corrosion of the iron structure by providing a tough metallic zinc envelope, which completely covers the surface of the structure and seals it from the corrosive action of its environment.
Hot-dip galvanizing involves three main steps:
Preparation: The galvanizing reaction can only occur on a chemically clean surface, so the first step of the process involves removing any contamination on surface of the iron structure.
Galvanizing: The clean iron structure is dipped into the molten zinc, and held there until the temperature of the iron quilibrates with that of the bath. The structure is then pulled-out & allowed to cool.
Inspection: After galvanizing, the coated materials are inspected for coating thickness, uniformity and coating appearance.
It is advisable to have galvanization post-fabrication of the structure in order to avoid any damage to the galvanized layer. The thickness of galvanization varies from 40 -150 micros depending on the local site conditions and requirements.