Although PPGL (pre coated aluminum zinc steel coil) has excellent corrosion resistance and weather resistance, its aluminum zinc alloy coating (55% aluminum) has inherent shortcomings and is not suitable for all scenarios. Using the wrong environment can accelerate corrosion, so it is important to pay attention to the following limitations.
Clearly not applicable: Four types of restricted areas
-Strong alkaline environment: When in contact with concrete or mortar, the aluminum rich phase in the coating will be corroded by alkaline substances, and galvanized steel (GI) or stainless steel should be used instead.
-Animal farms: Chicken and pig coops have high ammonia concentrations, which can corrode aluminum phases and cause rapid rusting. Galvanized steel or specialized ammonia resistant coatings are required.
-Contact with copper: Contact with copper materials or rainwater containing copper can cause aluminum copper galvanic corrosion, and stainless steel must be used instead.
-Soil contact or freshwater immersion: Aluminum phase is prone to corrosion in soil and freshwater, and galvanized steel or Galfan should also be selected.
Performance shortcomings that need attention
-Weak formability: The coating is brittle and not suitable for tight bending (0T/1T is prone to cracking). It is recommended to use PPGI for deep drawing and heavy processing parts.
-Limited protection for cutting edges: relying on aluminum barriers for corrosion prevention rather than sacrificial protection is not suitable for components with large exposed edges and welding.
-Fairly weldable: weldable but requires parameter adjustment, not as convenient as pure galvanizing.
