55% AFP/NAFP 0.13mm thickness 914mm width Galvalume Steel Coil using for roofing sheets

Introduction of galvalume steel coil :

The galvalume & aluzinc steel sheet in coil uses the cold-rolled steel sheet as a substrate and solidified by 55% aluminum, 43.4% zinc and 1.6% silicon at 600 °C. It combines the physical protection and high durability of aluminum and the electrochemical protection of zinc. It is also called aluzinc steel coil.

Chemical Requirements of SS Grade 37[255]:

Details of galvalume steel coil :

Advantage of galvalume steel coil :

• Strong corrosion resistance, 3 times that of galvanized steel coil.
• The density of 55% aluminum is smaller than the density of zinc. When the weight is the same and the thickness of the plating layer is the same, the area of the galvalume steel sheet is 3% or larger than that of the galvanized steel sheet.

Surface Treatment Of Galvalume Steel Coil / Sheet:

Detailed Steps Of The Galvalume Steel Sheet Processing

Step 1:

Pre-treatment: After the cold-rolled coil arrives in the galvalume workshop, after passing through the uncoiler, through the degreasing section and the reduction furnace, the steel coil is cleaned and its components are reduced to the extent that it can be galvanized.

Step 2:

Central section: The most critical technology is this step. After passing through the zinc pot, a layer of zinc layer is plated on the surface of the steel plate. After coming out of the zinc pot, it is cooled and shaped by the cooling tower.

Step 3:

Post-processing: The steel plate finally comes to the post-processing stage after various processes. After finishing, straightening and passivation, and finally coiling.

Galvalume Steel Coil Features:

• Thermal Reflection:

People use it as material for heat-insulation for its thermal reflectivity as high as twice the galvanized steel sheet.

• Heat-resistance:

The aluzinc steel sheet could bear above 300℃ high temperature with its good performance in heat-resistance, quite similar to the aluminized steel sheet’s performance in oxidation-resistance under high temperature. It is often used for chimney pipe, oven, illominator, and fluorescent lamp cover.

• Corrosive-resistance performance:

The essential of galvalume steel coil’s corrosive-resistance lies at aluminium’s protective property. Once the zinc come under abrasion, the aluminium would form a layer of densified oxidized aluminium, preventing the interior from further corrosion.

• Economical:

The density of 55%AL-Zn is smaller than Zn, therefore, with the same weight and thickness of coating, the galvalume steel sheet is 3% larger in area than that of galvanized steel sheet.

• Easily painted:

There is perfect adhesiveness between galvalume sheet and paint, saving the process of pre-treatment and weathering for painting work.

The coating material on the galvalume steel sheet is outstanding in its adhesiveness, which could be directly tarring on the advertising board and commonly used board with no pre-treatment such as weathering process.

• The galvalume steel sheet’s surface is luxury in silver colored appearance.
• Galvalume steel sheet and galvanized steel sheet are similar in performance of processability and painting.

Here are the pictures of our Mill as reference :