Comprehensive analysis of metal plate powder coated steel and aluminum bending and welding frame parts

1. Processing selection of metal plate powder coated steel and aluminum bending and welding frame parts
Steel: galvanized steel or cold-rolled steel is preferred, with a thickness range of 0.5-4mm, suitable for high-load parts, and structural parts need to be formed through bending process.
Aluminum: 5052, 6061 and other aluminum alloys are commonly used, with a thickness of 0.8-3mm, lightweight and corrosion-resistant, but galvanic corrosion caused by direct contact with steel should be avoided.
Powder coating compatibility: Steel and aluminum need to be pre-treated separately (such as galvanized steel needs phosphating treatment, aluminum needs chromizing treatment) to ensure coating adhesion.

2. Optimization of bending process parameters
Angle and radius: The bending radius of steel needs to be ≥ plate thickness (such as 1mm plate thickness radius ≥ 1mm), and aluminum can be appropriately reduced due to better ductility, but cracking of powder coating needs to be avoided.
Sequence and strength: Multiple bends need to follow the order of "outside first, then inside" to avoid stress concentration. For example, the bending force is controlled at 0.2-0.8MPa, combined with precise control of servo motor to avoid coating damage.
Spraying after bending: Recommended process flow to avoid coating peeling during bending. Flexible powder coating should be used after spraying.

3. Powder coating process
Steel parts: degreasing → phosphating → passivation to enhance the adhesion of the coating (adhesion ≥ 5MPa).
Aluminum parts: degreasing → chromization (such as aluminum gas welding solvent containing KCl/NaF) to improve the corrosion resistance of the oxide film.
Spraying parameters: voltage 60-80kV, powder particle size 15-50μm, film thickness 40-80μm.
Curing process: baking at 135-150℃ for 20-30 minutes to form a cross-linked coating (such as epoxy-polyester mixed system).