Aluminum Welding for Reefer Containers & Insulated Bodies

Common base metals and welding conditions

The core requirements for reefer bodies are corrosion resistance and air-tightness: the body serves in cold, damp, frequently temperature-cycling and coastal salt-spray conditions, so the seams must both resist corrosion and stay continuous and dense to keep the insulation dry and the body reliably sealed. The structure is mainly thin-wall panels joined to an extruded frame, with long straight seams welded in high volume. The base-metal combinations most commonly encountered on the floor are as follows:

• 5052 / 5754 panels: medium strength with good formability and corrosion resistance — the most common thin-sheet base metal for reefer panels and inner/outer skins, well suited to continuous welding of long straight seams.
• 5083 extrusions and load-bearing parts: higher manganese content with stronger resistance to seawater and salt spray, typically used on underframes, door frames and load-bearing structures in more demanding locations.
• Thin-sheet behavior: panels are thin with low heat capacity, prone to distortion and burn-through during welding, so heat input must be controlled and the welding sequence planned sensibly to keep the body flat and dimensionally accurate.
• Reefer-body seams are long and similar joints are repeated in high volume, so the wire's payoff smoothness, feeding stability and batch-to-batch consistency are especially critical — stable feeding directly affects the quality and air-tightness of continuously welded long seams.

Practical welding notes

• Corrosion resistance first, ensure air-tightness: the body lives in cold, damp, salt-spray conditions, so seams must be continuous and dense, free of porosity and lack of fusion, to keep the insulation dry and the body sealed. Choosing 5xxx-series Al-Mg wire and controlling weld quality is the foundation of corrosion and moisture resistance.
• Thin-sheet distortion and burn-through control: panels are thin, so control heat input and welding current, apply symmetrical and back-step welding with a sensible sequence, and use rigid fixturing and backing to reduce cumulative distortion and burn-through, keeping the body flat and dimensionally accurate.
• Continuous welding of long straight seams, stable feeding: panel seams are long, and feeding smoothness directly affects continuous-welding efficiency and seal quality. TGM wire is layer-wound with a clean surface and uniform diameter, giving smooth payoff without knotting or jumping, suited to large packages and long continuous welding with fewer feed stoppages.
• Proper cleaning, adequate shielding: before welding, thoroughly remove the oxide film, oil and moisture, and shield with pure argon or an argon-helium mixture to reduce porosity and improve weld density — especially critical for the corrosion resistance and air-tightness of reefer bodies.