Why Can Galvanized Steel Coils Prevent Rust? Comprehensive Analysis of The Principle of Anti-corrosion

In the application scenarios of steel, "rust prevention" is a performance indicator that almost all users care about. Compared with ordinary steel, which is prone to oxidation and corrosion, galvanized steel coils (Galvanized Steel Coils) are widely used in construction, automobiles, home appliances, agriculture and other industries due to their superior corrosion resistance. So the question is: How does galvanized steel coil prevent rust? What is its anti-corrosion principle? This article will reveal the answer for you.

1. Why is galvanized steel not easy to rust?

Ordinary steel is easily oxidized when exposed to air or high humidity, forming rust on the surface, reducing strength and service life. The surface of galvanized steel coils is covered with a layer of zinc, which is the "protective barrier" to prevent steel corrosion.

Galvanized steel coils are commonly used for:

1. Building structures such as roof panels and wall supports

2. Automobile chassis, sheet metal parts

3. Cooling equipment, agricultural machinery

4. Home appliance shells and internal components

2. What is zinc layer protection? ——Corrosion prevention starts from the "surface"

The protective effect of the zinc layer is divided into two types of galvanizing methods:

1. Hot-dip galvanizing: immerse the steel coil in molten zinc liquid to form a thick and uniform zinc layer

2. Electrogalvanizing: zinc ions are deposited on the steel surface through electrolysis to form a smooth coating

No matter which method is used, the ultimate goal is to form a protective film that can prevent steel from direct contact with air and moisture. This layer of zinc is not just a "waterproof layer on top", it also has a key ability-sacrificial anode protection.

3. The triple anti-corrosion mechanism of the zinc layer

1. Physical barrier effect

The zinc layer first acts as a physical isolation wall to isolate corrosive substances such as moisture, oxygen, acid and alkali from direct contact with the steel surface, slowing down the oxidation process.

2. Inert oxide film protection

When zinc reacts with oxygen and water in the air, zinc oxide (ZnO) is generated, which is further converted into zinc carbonate (ZnCO₃). This is a dense white film that adheres to the surface of the zinc layer and plays a role in self-repair and corrosion prevention.

3. Electrochemical protection

This is the core anti-rust principle of galvanizing. When the surface of galvanized steel is scratched or damaged, zinc, as the "anode" in electrochemistry, will preferentially undergo corrosion reactions and sacrifice itself to protect the iron substrate. This is called "sacrificial anode protection", and the steel is still protected even if the zinc layer is incomplete.

4. Relationship between zinc layer thickness and anti-corrosion performance

The thicker the zinc layer, the stronger the anti-corrosion performance and the longer the service life. The common zinc layer representation unit is the Z value, for example:

Note: Humidity and salt spray environment in different regions will also significantly affect the anti-corrosion life.

5. External factors affecting the anti-corrosion performance of galvanized steel coils

In addition to the zinc layer itself, there are several external factors that will also affect the anti-rust ability of steel coils:

1. Use environment: coastal, high humidity, acid rain areas consume the galvanized layer faster

2. Edge cutting/stamping damage: If the exposed edge is not treated, it may rust first

3. Whether it is coated or coated: coated or color-coated products have stronger protection

4. Storage method: Rain, stacking without ventilation, etc. will accelerate corrosion

It is recommended that customers keep galvanized steel coils dry, ventilated, and avoid moisture accumulation when storing them.

6. Galvanized steel vs. stainless steel: Which one is more anti-corrosive?

Although both have anti-rust capabilities, the principles and applicability are different:

Summary: If you are looking for an economical and cost-effective anti-corrosion solution, galvanized steel coils are a more mainstream choice.

7. Conclusion: Correctly understand the principle of anti-corrosion and choose the right galvanized material

The reason why galvanized steel coils can be rust-proof for a long time is that its zinc layer has a triple mechanism of barrier protection + self-repair + electrochemical sacrificial anode. Understanding these principles will help purchasers to more reasonably select materials, judge the thickness of the zinc layer, and evaluate the service life.

If you are looking for a high-quality galvanized steel coil supplier, we can provide you with a variety of galvanized layer grades such as Z80-Z275, support customized processing and export wholesale services, welcome to consult for quotes and technical support!