Galvanizing is the process of coating a metal (typically steel or iron) with a protective zinc coating as a means of corrosion protection. This is most commonly achieved by a process known as hot-dip galvanizing, where the steel or iron is immersed in a bath of molten zinc to provide a uniform, protective coating throughout the submerged metal.
Trenchlesspedia Explains Galvanizing
Galvanizing protects steel by offering two types of protection:
- Barrier protection – The zinc coating dries and hardens forming an impervious layer that prevents the steel from coming into contact with air and moisture.
- Galvanic protection – The zinc coating acts as a sacrificial anode and corrodes preferentially to the underlying steel even if scratched.
Galvanized steel pipes were popular in the United States prior to 1960. Although galvanizing is meant to promote corrosion resistance in steel pipes, it was by no means permanent. It is generally recognized that galvanized steel pipes have a life expectancy of 40-50 years. Decades of exposure have caused galvanized pipes to corrode internally resulting in a number of problems including:
- Low water pressure
- Uneven distribution of water
- Discoloration of water
The rise in issues with galvanized pipes has also sparked a rise in trenchless methods to repair and replace galvanized pipes.