Sempurna Engineering & Trading

Aluminized Steel Type 2

Aluminized Steel Type 2, is a metallic jacketing recommended by CINI for the applications of hot/cold/sound insulation and weatherproofing. Hot-dip coated for exceptional metallurgy in accordance with ASTM A463/A463M T2 300, it gives Aluminized Steel Type 2 the combined advantage of steel and aluminum.

Because of its excellent resistance against atmospheric corrosion and fire, it is widely used in Refineries, LNG receiving Terminals, Chemical and Petrochemical industries worldwide. The use of Aluminized Steel Type 2 results in decreased maintenance costs and increased safety.

Difference between Aluminized Steel Type 1 & Type 2

Understanding the difference between the types and their applications

Type 1 is an aluminium silicon alloy, containing 5 to 11% silicon. The silicon has been added to the aluminium coating in order to obtain a combination of heat - and corrosion resistance above 400°C.

Main applications are situated in automotive, such as exhaust pipes, heat shields and mufflers.

The problem with Aluminized Steel Type 1 in the case of insulation cladding (where heat of above 400 deg Celsius is not involved), is that the presence of silicon reduces the corrosion resistance. Reason : from literature it is known that the silicon phase is more noble than the surrounding aluminium alloy (particles are cathodic). The rate of attack is governed by the cathode/anode area ration.

Aluminized Steel Type 2 is a commercially pure aluminum. It is intended principally for use in applications requiring corrosion resistance.

Main applications are insulation cladding (hot and cold), drainage pipes, roofing & siding of buildings.

Conclusion : Type 1 Alu-Si coating has never been developed for cold outside applications (where heat of above 400 deg Celsius is not involved) , and therefore cannot be successful for insulation cladding. A polyester or silicon sealer coat will not be helpful to avoid galvanic corrosion of Aluminized Steel Type 1 applied as insulation cladding.

The main reason is that most of the coatings are only weak U.V. resistant. As soon as the coating is damaged or destroyed, corrosion will occur very soon. Cutted edges will never protect themselves by oxide formation.

However, cutted edges of Aluminized Steel Type 2, due to the commercially pure aluminium, will protect themselves by the formation of an aluminium oxide layer.

For this reason, we will never make any quotation for Aluminized Steel Type 1 to be applied as insulation cladding.

Type 2 is the only Aluminzed Steel that is sucessful for Insulation Cladding.

	Aluminized Steel Type 1	Aluminized Steel Type 2
ASTM Specification	A 463/A 463M T1	A 463/A 463M T2 300
Composition Coating	Aluminum Silicon	Commercially Pure Aluminum
Atmospheric corrosion Resistance	Poor	Excellent
Mechanical Strength	Excellent	Excellent
Main Application	Car Exhaust, Muffler, Heat shield.	Hot/Cold Insulation Cladding Material