To galvanise steel, carbon steel is coated in zinc through a process known as hot dip galvanisation. This provides basic barrier protection by submerging the steel in a zinc bath heated to 360 C degrees.
Once the metal is removed from the zinc dip, a reaction occurs with the oxygen in the air and the zinc bonds to the steel to form an alloy – this creates the well-known spangled finish.
This process results in a triple level of corrosion resistance – barrier and cathodic protection and the final zinc patina. However, it can be difficult to control the thickness of the finished product, which is why the continuous galvanising process has developed.
Now imagine a continuous ribbon of steel passing through a zinc bath at 600 feet per minute. This process applies a thin and standardised layer of molten zinc that is then cut using high-pressure air to the right thickness.
The result is a more precisely controlled thickness, making it the savvy choice for articles that have not yet been fabricated. The uniform coating eliminates weak spots in the galvanisation and results in safer handling. The zinc coating is also more ductile, providing superior resistance to abrasions throughout the lifespan of the product.
The reliability of the zinc coating and the long life expectancy of galvanised steel make it a cost-effective alternative to stainless. In fact, no other coating provides such an effective coating as zinc because the rate of corrosion is so slow and the cathodic protection means that small areas of steel that may become exposed are not vulnerable to rust.
When ready to install, no time is lost with surface inspections. Owing to the level of surface protection, it’s easy to inspect a galvanised steel product by eye because every part of the product is protected, including hidden areas. Manufacturers and consumers alike find galvanised steel a desirable and long-lasting product.