1. General stabilization cycle under natural outdoor conditions
Under typical inland atmospheric environments (urban / rural with normal wet‑dry cycles),the surface rust layer of S355J2WP usually takes 24 to 36 months to fully stabilize.
2. Stage‑by‑stage change process
0–3 months: Early rustingSurface turns yellow → orange‑red; loose rust, obvious runoff, color unstable.
3–12 months: Transition periodRust layer gradually densifies; color deepens to reddish brown → dark brown;runoff reduces significantly.
12–24 months: Basic stabilizationPatina becomes dense and adhesive; color tends to be stable dark brown;almost no more rust runoff.
24–36 months: Full stabilizationPatina matures completely; no further obvious color change or corrosion progression.
3. Time differences in different environments
Industrial / SO₂‑containing atmosphere:Stabilizes faster, about 18–24 months, due to faster patina formation.
Clean rural atmosphere:Slower reaction, stabilization takes 24–36 months.
High humidity, poor ventilation, long‑term damp:Cannot form stable patina; rust remains loose for years, never fully stabilizes.
Coastal salt‑spray areas:Stabilization is delayed or incomplete; may take 3 years or longer,and the layer remains uneven.
4. Features of a fully stabilized rust layer
Uniform dark brown / grayish‑brown color
Dense, tight, not easy to fall off
No obvious rust runoff when raining
Corrosion rate drops to a very low level
