specific surface preparation is required for ASTM A606‑2 before welding to ensure weld quality, prevent defects, and preserve its corrosion resistance and natural patina development.
1. Contamination Removal
All oil, grease, dirt, paint, moisture, and mill scale must be removed from the welding joint and at least 10–20 mm around it.Contaminants cause porosity, cracking, and poor fusion, and can disrupt the formation of the protective patina.
2. Rust and Loose Scale Removal
Remove loose rust and scale from the joint area.Dense, tightly adherent mill scale may remain if it is not loose, but heavy or flaky scale must be cleaned off.
3. Wire Brushing Requirements
Use a stainless steel wire brush only.Do not use carbon steel brushes, as they leave iron particles on the surface that cause uneven corrosion and rust spots.
4. Edge Preparation
Cut edges (especially from oxy‑fuel or plasma cutting) must be ground smooth to remove hardened or oxidized edges.Rough or burnt edges trap moisture and corrode unevenly.
5. Dry Surface Condition
The welding zone must be completely dry before welding.Moisture causes hydrogen cracking and porosity in weathering steel welds.
6. Avoiding Unnecessary Grinding
Do not over‑grind or polish the entire surface.Excessive grinding removes the natural surface that supports uniform patina formation. Only grind where necessary for welding.
