Difficulties and Solutions in Aluminum Alloy Welding Process

Due to their low density and high strength, aluminum alloys are increasingly widely used in automotive, rail transit, aerospace, and other fields. However, aluminum alloy welding is much more difficult than steel welding. This article systematically analyzes the difficulties of aluminum alloy welding and provides practical solutions.

I. Main Difficulties in Aluminum Alloy Welding

1. Oxide film issue: Al₂O₃ has a melting point as high as 2050°C, far above aluminum’s melting point (660°C)

2. Porosity sensitivity: hydrogen’s solubility in liquid aluminum is 20 times that in solid state

3. Hot cracking tendency: large solidification range, prone to crystallization cracks

4. Large deformation: expansion coefficient is 2 times that of steel

5. Similar color: difficult to observe molten pool state

II. Welding Method Selection

III. Porosity Prevention Measures

Porosity is the most common defect in aluminum alloy welding. Prevention measures include:

• Thoroughly clean both sides of the groove (chemical cleaning or mechanical cleaning)

• Use high-purity argon (99.99% or above) for shielding

• Control environmental humidity (relative humidity <60%)

• Use appropriate welding parameters (avoid excessive or insufficient heat input)

• Preheating before welding (100-150°C) helps gas escape

IV. Typical Case: Power Battery Tray Welding

Power battery trays for new energy vehicles typically use 6000-series aluminum alloys, with extremely high welding requirements:

• Weld seam tightness: no leakage allowed

• Deformation control: flatness ≤1mm/m

• Appearance quality: uniform fish-scale pattern, defect-free

Recommended process solution: CMT welding + positioner + laser tracking + online monitoring