Post-Welding Treatment for Q500NH Weathering Steel
For most applications, Q500NH does not require mandatory post-weld heat treatment (PWHT)
General Fabrication (Non-Critical Structures)
Preheat (100–150℃) was properly applied
Low-hydrogen electrodes were used (e.g., AWS E7018)
<2 kJ/mm)
:
550–600℃ for 1–2 hours to reduce residual stresses
Especially for thick sections (>25 mm) or dynamic loads
:
After welding, the heat-affected zone (HAZ) loses its weathering resistance.
Natural repatination occurs over 6–12 months, or accelerate it with:
(e.g., dilute hydrogen peroxide spray)
-20℃
For pressure vessels or fatigue-loaded components (per EN 1993-1-10)
:
remove slag and clean weld zones to prevent crevice corrosion.
, grind welds smooth to ensure uniform patina development.
, consider applying weathering-resistant primers on weld seams.
