Choosing metals for your products is one of the biggest decisions of your project. The metal you choose will affect the durability, cost and overall success of the project. Steel is a good choice for outdoor metal environment that needs rust and corrosion prevention. However, not all steel is rust proof. Stainless steel and galvanized steel are two kinds of steel with rust resistance and corrosion resistance. Galvanized metal is one of the most popular and universal metal surface treatments. The versatility of this metal makes it suitable for a wide range of applications in different industries, including automotive, solar, electronics and construction industries.
What Is Galvanized Steel?
Compared with stainless steel that changes the chemical composition of steel (by adding chromium), galvanized steel is just a coating on the original steel. The applied coating is made of zinc, which forms a barrier between the steel and the moisture in the air, effectively separating it from elements that may cause rust. The zinc layer is softer and will sacrifice itself to protect the internal metal from scratches, corrosion, etc. Galvanizing is highly sustainable and generates the least waste.
Different Methods Of Galvanizing
Hot-Dip Galvanizing
As the name implies, this method is carried out by immersing the base metal in the zinc bath. Before actual galvanizing, the machinist must clean the base metal chemically, mechanically, or both. Cleaning is a preparatory process to ensure a quality bond between the metal and the zinc coating. After cleaning, the metal is fluxed to remove any remaining oxides.
In this method, steel or iron is immersed in a zinc bath and the temperature of zinc is maintained at about 860 ° F (460 ° C). This bath starts the metallurgical bonding between zinc and the receiving metal. After the metal is taken out of the plating solution, it will react when exposed to the atmosphere, and pure zinc will mix with oxygen to form zinc oxide. Zinc oxide further reacts with carbon dioxide to form zinc carbonate, which forms the final protective coating on the material.
New coated materials can be processed and processed in a similar manner to uncoated materials. Galvanized steel can be used for high temperature applications up to 392 ° F, but use above this level will result in peeling of the zinc carbonate layer.
Hot dip galvanizing is an economical option that can be performed quickly on simple and complex shapes.
Galvannealing
Galvanizing is a combination of hot-dip galvanizing and annealing process. This process aims to produce galvanized steel with special coating. The annealing and hot dipping processes occur instantaneously to produce a matte grey finish.
The hot soak process usually occurs before passing the coated metal through the air knife. Air knives help remove excess zinc from the metal. The metal is then heated briefly in an annealing furnace at 500 to 565 ° C. Then zinc layer and iron layer diffuse each other to form zinc iron alloy.
The galvanized steel sheet produced by this method can withstand welding well, and the surface ensures excellent paint adhesion.
Pre-galvanizing
It is also similar to the hot-dip galvanizing method, but it is carried out in the first stage of production. Pre galvanizing is a process that involves rolling the sheet metal over the cleaner to quickly prepare the material for galvanizing. The metal then passes through the molten liquid zinc bath and is immediately recoiled. The main advantage of this method is that compared with the traditional hot dip method, the steel coil can be galvanized rapidly and in large scale, and the coating is more uniform.
However, some uncoated and exposed areas may occur when fabrication of pre galvanized metal begins. For example, when a longer metal sheet roll is cut into smaller pieces, the edges will be exposed.
Electrogalvanizing
One of the most unique of these outlined methods, galvanization does not involve immersing the material in a molten zinc barrel. Instead, a current is introduced into the electrolyte solution applied to the steel, reducing the positively charged zinc ions to zinc metal, and then depositing on the positively charged steel. Like pre galvanizing, this method is usually carried out in the first stage of production.
Benefits of Galvanized Steel
1. Economic Benefits
The total cost of galvanizing is lower than other coatings. If you want to save money on construction projects, you need to make sure to switch to galvanized steel as soon as possible.
2. Durability
Coating life and performance are reliable and predictable. You will find that one of the greatest advantages of galvanized steel is that it is more durable than ordinary steel. The coating helps protect the material and reduces the chance of corrosion.
3. Less Maintenance
Galvanized steel has a much longer service life than other materials and requires less maintenance. In the long run, this will save you time and resources that can be better used elsewhere to maintain your projects and materials.
4. Hardest Coating
The galvanized coating has a unique metallurgical structure, and has excellent mechanical damage resistance during transportation, installation and service. It is one of the toughest coatings on the market today, allowing you to use it in harsh weather conditions and conditions.
5. Complete Protection
Every part of galvanized products is protected, even in grooves, sharp corners and inaccessible areas. Any coating applied to the structure or fabrication after completion shall not provide the same protection.
6. Easy To Check.
Galvanized coatings can easily be assessed by the naked eye, and simple non-destructive thickness testing methods can be used. The galvanizing process is like this: if the coatings appear to be intact and continuous, they are intact and continuous.
7.Speedy Application
The galvanizing process is independent of weather conditions. It can be completed in minutes and provides a complete protective coating at any time of the year. This is especially important for anyone living in an area where weather conditions are constantly changing.
8. Faster Installation Time
After receiving the galvanized steel members, they can be used. Surface preparation, painting and inspection at site are not required. After the structure is assembled, it can be put into use immediately or enter the next construction stage.