BEST WAY TO WELD GALVANIZED STEEL

Best Way to Weld Galvanized Steel

Best Way to Weld Galvanized Steel

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1. Manual Arc Welding

Preparation Before Welding

To reduce smoke and prevent cracks or pores, proper preparation is necessary:

  • Remove the zinc layer near the groove using flame baking or sandblasting.
  • Control the groove gap:
    • 1.5–2mm for most workpieces.
    • 2.5–3mm for thicker materials.

Selection of Welding Rods

The welding rod should match the mechanical properties of the base metal, with silicon content below 0.2%.

  • For low-carbon galvanized steel, use J421, J422, or J423.
  • For 500MPa+ strength galvanized steel, use E5001 or E5003.
  • For 600MPa+ strength galvanized steel, use E6013, E5503, or E5513.

To minimize smoke and preserve corrosion resistance:
✅ Use a short arc.
✅ Avoid arc swinging.

2. Gas Shielded Welding

Shielding Gas Options

Gas type affects Zn content in the weld:

  • Higher Zn content: Pure CO₂ or CO₂ + O₂.
  • Lower Zn content: Mixed Ar + CO₂ or Ar + O₂.

Fume and Penetration Considerations

  • More fumes are produced than in manual arc welding. Proper ventilation is crucial.
  • Fume amount increases with:
    • Higher current.
    • More CO₂ or O₂ in shielding gas.
  • ZnO content in fumes can reach 70%.

Porosity and Welding Speed

  • T-joints, lap joints, and vertical welds are prone to porosity.
  • Higher welding speed increases porosity risk, especially for galvanized alloy steel.
  • In multi-pass welding, later welds are more prone to porosity than earlier ones.

Impact on Mechanical Properties

  • Shielding gas has little effect on mechanical strength.
  • Pure CO₂ is generally recommended.

Conclusion

Proper preparation, correct electrode selection, and careful control of welding parameters ensure strong, durable welds on galvanized steel. Adequate ventilation and process adjustments help minimize porosity and fumes for a successful welding process.

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