Galvanized Steel and How It Works
Will Galvanized Steel Rust?
In short, yes but it takes at least 10 years before it may start to rust - under normal usage and conditions. When maintained properly, we have many clients who feedback that our Boltless Racks are still in good condition and rust-free, even after 15 years of usage. Here are some TLDR notes:
- Galvanized Steel is like the younger brother and cheaper alternative to Stainless Steel. It doesn't require a layer of powder-coat to resist rust.
- You can use surface cleaner and damp cloth to clean it.
- Do not let liquid puddle on the surface for prolonged period of time (i.e. a box with liquid content leaking at the base). This will accelerate rust process.
- Do not let strong chemical puddle on the surface for prolonged period of time (i.e. a bleach bottle with its base still wet with bleach). Most if not all metals will corrode when they come in contact with strong chemical, often in matter of days.
So what makes Galvanized Steel so popular and widely used in Singapore? If you look around carefully, you will realize that our street lamp posts, highway barriers, street fences, drain covers and sheltered walkways are often made of Galvanized Steel.
Our Light Duty Boltless Storage Racks are made of Galvanized Steel to ensure product durability and corrosion protection. Despite the fact that hot-dip galvanization was first practiced in the 17th century and subsequently widely applied by many industries, galvanized steel remains a mystery to many modern consumers.
What is Hot-dip Galvanizing?
Hot-dip galvanizing involves the immersion of steel work-pieces into a bath of molten zinc heated to a temperature of approximately 450 Celsius. The zinc alloys with the surface of the base metal to form a protective finish. The zinc reacts with the oxygen in the atmosphere to form zinc oxide. The most important benefit of hot-dip galvanization is enhanced protection against corrosion.
Difference between Galvanizing and Powder Coating
A primary difference between galvanization and powder coating is the way they protect the surface of the work-piece.
Galvanization provides sacrificial protection, meaning the finish will absorb corrosive materials before they can reach the metal object.
Powder coating works by forming a protective barrier that prevents destructive materials from penetrating and reaching the surface. However, powder coating is porous and can easily damage under force or hard scratches. Once penetrated, the corrosion resistance is compromised and moisture can reach the underlying layer of metal easily. This is why users often find their metal racks corroding and rusting beneath the layer of powder-coat, that is supposed to protect it.
With galvanized steel as the underlying material, even with no powder-coat or if the powder-coat is scratched, it will not rust easily and spread internally beneath the layer of powder-coat.
Benefits of Galvanized Steel
- Less Maintenance Required – Self-maintaining and thicker, resulting in maintenance cost of steel items is inevitably lower.
- Longer Life – Under normal atmospheric condition, it can last in excess of 10 - 20 years, continually protecting steel against corrosive elements.
- Lower Costs – Lower initial cost than a lot of other commonly specified corrosion protection coatings for steel, such as Stainless Steel.
- Environmentally Friendly – The longevity of the maintenance-free coating provides environmental and economic benefits. Zinc exists naturally in the world so the zinc byproducts released into the atmosphere are not harmful.
Using Galvanization and Powder Coating Together
It’s possible to combine hot-dip galvanizing with powder coating to form a duplex system for protecting metal materials. The galvanized zinc serves as a base finish that enhances corrosion protection. The powder coating provides a top layer that slows down the rate in which corrosion consumes the underlying zinc. The powder coating can also improve the aesthetic appeal of the metal object.