Table of content
Introduction
The term galvanizing often appears with steel pipes. The main purpose of galvanizing is to prevent rust and corrosion of steel pipes. So, in addition to galvanizing on steel pipes, what other places need galvanizing? What is the main purpose and function of galvanizing? Let’s read the article with these questions below to find the answers.
What Does Galvanizing Do?
The main function of galvanizing is to prevent rust and corrosion. It is to coat a thin layer of zinc on the surface of steel or iron. The main function of zinc is to prevent moisture and atmosphere from penetrating the metal, and a small scratch on the galvanized layer will not have a big impact.
What Is the Purpose of Galvanizing?
Its main purpose is to prevent corrosion and rust. Because in outdoor or industrial environments, steel and iron are more likely to rust due to long-term exposure to air and moisture. If the time is too long, it may cause damage to the structural components of finished products such as pipes and fences.
Why zinc?
Because zinc corrodes slower than steel or iron, and is applied on the outer layer to act as a sacrificial layer. When the galvanizing layer is completely corroded, the steel or iron inside is still intact.
How Does Galvanizing Work?
Galvanizing is to add a layer of zinc to the surface of objects such as steel pipes to play a physical protective role.
1. Barrier protection
The galvanizing layer can isolate some moisture and oxygen from contact, thereby extending the service life.
2. Sacrificial protection
In a corrosive environment, the galvanizing layer corrodes first, which is called electrochemical protection. If there is a scratch, the galvanizing layer is scratched first.
Does Galvanizing Make Steel Stronger?
No, the galvanizing layer will not improve the mechanical properties of steel, but only play a certain anti-corrosion role. The various properties and load-bearing capacity of the steel itself will not change, but the service life will be longer than that of the original steel.
So in real-world terms:
- Unchanged strength
- Increased durability
- Longer life
Types of Galvanizing Processes
There are 3 ways to galvanize steel, but which one to choose needs to be selected according to the actual application.
1. Hot-dip galvanizing
This is the most commonly used galvanizing method. It mainly involves cleaning the steel and dipping it in molten zinc to form a thick, bonded coating.
Best for: steel pipes, industrial parts, outdoor buildings, etc.
2. Electro-Galvanizing
Use electric current to deposit zinc onto the metal surface. Compared with hot-dip galvanizing, electrogalvanizing forms a thinner and smoother galvanized layer.
Best for: automotive parts, home appliances
3. Galvanizing annealing
The combination of hot-dip galvanizing and annealing can improve the performance of the galvanized layer and form a matte surface.
Best for: Steel galvanizing
Advantages of Galvanizing
Galvanized steel is widely used, from industrial pipes to household items. Here are the reasons:
Long-lasting protection
Galvanized steel has a relatively high service life, mostly more than 50 years, and can reach about 25 years in some coastal humid areas.
Low maintenance cost
No frequent re-galvanizing after use.
Economical
Galvanizing has better corrosion resistance and is more economical in the long run.
Full Coverage
The galvanized layer is more comprehensive, and the edges, corners and interior can be galvanized.
Where Is Galvanized Steel Used?
Common Uses:
- Steel Pipes
- Fences
- Car bodies and frames, etc.
- Signs and light poles
- Building structure supports
Galvanizing vs Stainless Steel
Galvanized steel and stainless steel are two different types of steel, and their performance and characteristics are different:
| Feature | Galvanized Steel | Stainless Steel |
|---|---|---|
| Main Element | Zinc coating | Chromium alloy |
| Corrosion Resistance | Moderate to high | Very high |
| Cost | Lower | Higher |
| Appearance | Matte or spangled silver | Shiny silver |
| Best For | General outdoor use | Food, marine, medical use |
In highly corrosive environments, stainless steel is the best choice. But in most environments, galvanized steel is more economical.
Galvanizing Process (Step-by-Step)
The following are the production process steps of hot-dip galvanizing:
- Cleaning: Remove rust, stains and scale from steel.
- Pickling: Immerse in an acid bath to remove all oxides.
- Fluxing: Apply a layer of zinc ammonium chloride to increase the bonding strength with zinc.
- Galvanizing: Place the product in molten zinc.
- Cooling: After galvanizing, take it out and cool it. It can reach the best state.
Summary
Galvanizing is to protect steel from corrosion, which is also a method of corrosion prevention. The principle is to add a layer of zinc on the surface of steel, which can effectively block moisture and oxidation.
To recap:
- Galvanizing can increase the service life of the steel itself.
- Galvanized pipes are widely used.
- Galvanizing is affordable and does not require frequent maintenance.
The above is an introduction to the galvanized layer. I hope it will help you choose whether to add a galvanized layer to the product.
