What is Galvalume Steel Coils (GL)?
Galvanized steel coil is a metal material with a 55% aluminum-43.4% zinc-1.6% silicon alloy coating on the surface of cold-rolled steel through a hot-dip process. It combines the corrosion resistance of aluminum and the sacrificial anode protection of zinc. It is an upgraded substitute for galvanized steel and is widely used in construction, home appliances, automobiles and other fields.
What is the difference between galvanized steel coil and galvanized steel?
Galvalume Steel Sheet & Coil has strong corrosion resistance, which is 3-8 times that of ordinary galvanized sheets. It has good heat resistance and can be used in high temperature environments of 315℃. The zinc layer and paint have excellent adhesion. When used as a sign board or for general purposes, it can be painted without pretreatment and weathering treatment. Galvanized steel has relatively weak anti-corrosion performance and is easy to rust and fall off in harsh environments. Its heat resistance is not as good as that of aluminum-zinc steel coils. Generally, in a high temperature environment, the zinc layer will change color and fall off, affecting the protective performance.
What are the specifications of galvanized steel coils?
|
Item |
Specifications |
Notes |
|
Substrate material |
Low carbon steel (such as SPCC, DX51D), high strength steel (such as S350GD, S550GD) |
Choose the tensile strength grade according to the application |
|
Coating composition |
55% aluminum, 43.5% zinc, 1.5% silicon |
Corrosion resistance is better than ordinary galvanizing |
|
Coating weight |
Total amount on both sides: 30~300g/m² |
AZ60 means the total amount of double-sided is 60g/m² |
|
Thickness range |
Common models: AZ60, AZ100, AZ150, AZ200 |
Thin sheets for construction are usually ≤1.0mm |
|
Width range |
0.2mm~3.0mm |
Extra-wide coils (such as 2000mm) can be customized |
|
Inner diameter of steel coil |
Commonly used: 0.3mm, 0.5mm, 0.8mm, 1.0mm, 1.2mm, 1.5mm |
Adapt to standard unwinders |
|
Outer diameter of steel coil |
600mm~1500mm |
The maximum outer diameter is limited by transportation |
|
Mechanical properties |
Common: 1000mm, 1250mm, 1500mm |
High-strength steel may have lower elongation |
|
Surface treatment |
508mm (20 inches) or 610mm (24 inches) |
Anti-fingerprint treatment is commonly used in home appliance panels |
|
Implementation standard |
800mm~2000mm (depending on weight and thickness) |
Different standards have slightly different requirements for coating and performance |
|
Typical application |
Tensile strength: 270~550MPa |
Choose coating weight according to anti-corrosion needs |
Can galvanized steel coils be welded?
Galvanized steel coils can be welded, but attention should be paid to the difference between the surface alloy coating (55% aluminum + 43.4% zinc + 1.6% silicon) and ordinary carbon steel. During welding, problems such as coating melting, pores, and cracks may occur.
Recommended welding method
|
Welding methods |
Features and applicable scenarios |
Precautions |
|
Manual metal arc welding (SMAW) |
The equipment is simple and suitable for on-site welding, but the efficiency is low. |
Use short arc welding to reduce heat input and reduce coating burnout; the welding rod needs to be dried to avoid moisture and pores. |
|
Massive metal arc welding (GMAW) |
High efficiency and good weld quality, CO₂ or mixed gas (Ar+CO₂) is recommended. |
Use low current and fast welding speed to control heat input; gas flow rate 15 - 25L/min to prevent air intrusion. |
|
Pulsed MIG welding |
Precise heat input control, suitable for thin plates (≤2mm). |
Optimize pulse parameters (peak current, base current) to reduce coating evaporation and improve joint beauty. |
|
Laser welding |
Small heat-affected zone, suitable for high-precision welding (such as thin plates). |
High cost, professional equipment is required, and the coating of the welding area needs to be accurately removed in advance. |
