China Gl Galvalume Steel Coil Sheet for Roofing Sheets

Profile
The plating coat of Aluminium-Zinc Alloy Armor plate is Zn-Al alloy, and its composition is 55% Al, 43.3% Zn and 1.6% Si. The plate is of smooth surface and excellent corrosion resistance of the atmosphere, which is 2 to 6 times higher than hot-dip galvanized sheet of the same thickness of plating coat. After through three processes, including payoff reel, crop shear and welding, enter into the continuous annealing furnace. During the annealing process, strips are heated closer to the recrystallizing temperature, and then heated to 20~50 above the recrystallizing temperature in the reducing furnace. After keeping the same temperature for 170s, strips are naturally cooled to the normal temperature in the slow cooling process. Afterward, strips enter into the zinc pot through the elephant's trunk and begin in the hot-dip coating process. The optimum temperature range of the plating coat is 630~660. Coated with aluminium-zinc alloy, strips enter into the cooling tower by the steady roll and air knife. After fast cooled with wind or water, they are directly produced into Al-Zn armor plates. The general rate of cooling is 30 or so, and strips are cooled to about 60.
2. Specifciation
1. Production Grade: SGCC, DX51D, Q195
2. Thickness: 0.18-1.5mm
3. Width: 914mm, 1000mm, 1200mm, 1250mm mainly
4. Coating Type: 55%Al, 43.5%Zn and 1.5%Si
5. Coating Thickness (both side, g/sqm): 50-150
6. Surface Finish: Regular Spangle, Small Spangle
7. Surface Treatment: Oring or Anti-finger print
8. Inside diameters: 508mm
Outside diameters: As per customers' requirements

Chemical Requiremetns for structure steelComposition, %-Heat Analysis Element, maximum, unless otherwise ShownDesignationCMnPSCuNiCrMoVCbTiANBG2300.201.350.040.040.250.200.150.060.0080.0080.025^G2550.201.350.100.040.250.200.150.060.0080.0080.025^G2750.251.350.100.040.250.200.150.060.0080.0080.025^G3400.251.350.200.040.250.200.150.060.0080.0080.025^G5500.201.350.040.040.250.200.150.060.0080.0150.025^