language

Home

Products

Aluminium Silicon Coated Steel Tube

Aluminium-silicon coated steel tube is one of the most widely used heat-resistant coated steel products for automotive exhaust

Keywords:

Aluminium Silicon Coated Steel Tube

Category:

Aluminized Steel Coil / Tube

Inquiry Now

Send E-mail

File Download

sales1@tedaganghua.com

+86 22 86896631、+86 15822676888

Product Details

Aluminium-Silicon Coated Steel Tube: Why 5-11% Silicon Changes Type 1 Aluminized Performance

Aluminium-silicon coated steel tube is one of the most widely used heat-resistant coated steel products for automotive exhaust systems, industrial heating equipment, ovens, and thermal processing applications. The key difference between standard aluminum coating and Type 1 aluminized coating is the addition of silicon.

A typical Type 1 aluminium-silicon coating contains approximately 89-95% aluminum and 5-11% silicon. Although silicon represents only a small percentage of the coating composition, it significantly changes the coating structure, bonding behavior, and high-temperature performance.

Type 1 Al-Si Coating Composition and Function

During hot-dip aluminizing, aluminum reacts with the steel substrate and forms an intermetallic alloy layer at the interface. Without silicon control, this iron-aluminum reaction can become excessive, creating a thick and brittle layer.

Component	Typical Content	Main Function
Aluminum (Al)	89-95%	Creates protective aluminum oxide film
Silicon (Si)	5-11%	Controls alloy layer growth and improves coating quality
Steel Substrate	Base material	Provides strength and fabrication performance

Three Important Roles of Silicon in Al-Si Coating

Silicon is not simply an additional alloy element. It directly controls the metallurgical reaction between aluminum coating and steel substrate.

1. Controls Fe-Al Intermetallic Layer Growth

When aluminum contacts steel at high temperature, iron and aluminum react to form intermetallic compounds. If this reaction becomes too strong, the alloy layer becomes thick and brittle, reducing bending performance.

Silicon slows down excessive Fe-Al compound growth and creates a more balanced coating structure. This improves tube forming, bending, and fabrication performance.

2. Improves High-Temperature Oxidation Resistance

During heating, aluminum forms a dense aluminum oxide (Al₂O₃) protective film. Silicon helps stabilize this oxide layer and improves resistance against repeated heating cycles.

This is why Type 1 coating is widely selected for exhaust systems and thermal equipment where oxidation resistance is more important than normal atmospheric corrosion protection.

3. Enhances Coating Adhesion

The controlled alloy layer created by silicon improves the connection between coating and steel. This allows the tube to withstand bending, forming, and vibration during service.

Al-Si Coating vs Pure Aluminum Coating (Type 1 vs Type 2)

Not all aluminum-coated steel products are designed for the same environment. Type 1 and Type 2 coatings follow different performance strategies.

Comparison	Type 1 Al-Si Coating	Type 2 Pure Aluminum Coating
Composition	Aluminum + 5-11% Silicon	Nearly pure aluminum
Main Advantage	High-temperature oxidation resistance	Atmospheric corrosion protection
Typical Use	Exhaust, furnace parts, heat equipment	Outdoor and architectural applications
Forming Performance	Optimized for fabrication	Designed mainly for corrosion protection

Applications of Aluminium-Silicon Coated Steel Tube

Because of its combination of heat resistance, corrosion protection, and cost efficiency, Type 1 aluminium-silicon coated tubing is widely used in thermal applications.

Application	Reason for Selection
Automotive Exhaust Systems	Resists exhaust heat oxidation and condensation corrosion
Industrial Ovens	Maintains performance during repeated heating cycles
Boiler Components	Provides protection against hot gas oxidation
Heat Exchanger Tubes	Improves resistance in thermal environments

Temperature Performance Limit of Al-Si Coated Tubes

Type 1 aluminium-silicon coating provides excellent oxidation resistance in elevated temperature applications. Under normal service conditions, it can continuously protect steel components around 600°C, with short-term exposure approaching approximately 677°C.

Temperature Range	Performance
Below 600°C	Stable aluminum oxide protection
600-677°C	High-temperature oxidation protection zone
Above 677°C	Accelerated aluminum diffusion and coating consumption

How to Identify Al-Si Coated Steel Tube

Professional inspection methods are used to confirm coating quality and adhesion.

Silver-white metallic surface appearance.
Uniform coating without exposed steel areas.
Cup test or forming test to evaluate coating adhesion.
Coating thickness inspection according to specification requirements.

Aluminium-Silicon Coated Tube Supply Solutions

Teda Ganghua supplies aluminium-silicon coated steel tube products for automotive exhaust, industrial heating equipment, and high-temperature applications. Products can be customized according to dimensions, coating requirements, and fabrication needs.

For customers requiring Type 1 aluminium-silicon coated tubing with reliable coating performance, Teda Ganghua provides aluminised steel tube solutions for thermal and corrosion-resistant applications.