1.S355J0WP is NOT a heat-resistant steel, so it cannot be used in long-term high-temperature environments.It is designed for atmospheric corrosion resistance at normal temperatures, not high-temperature strength or oxidation resistance.
2. Allowable temperature range
Continuous service: ≤ 250°CAbove this temperature, the steel begins to show obvious strength loss and accelerated oxidation.
Short-term occasional exposure: up to 350°CProlonged use above this will cause permanent mechanical property degradation.
Not recommended: Any environment above 400°C
3. Performance changes at high temperatures
Tensile & yield strength decreaseAs temperature rises, S355-level strength drops significantly, no longer meeting structural design requirements.
Rapid oxide scalingHigh temperature accelerates surface oxidation; the protective patina fails and peels off, forming loose red scale.
Microstructure softeningPearlite spheroidization and grain growth occur, reducing toughness and increasing brittleness.
Creep deformation riskUnder load at high temperatures, the steel will slowly deform over time.
4. Behavior in medium-temperature environments (200–350°C)
Surface will form a thick, brittle oxide layer instead of a normal weathering patina.
The layer cracks and spalls easily, leading to progressive material loss.
Weathering performance is completely lost; corrosion becomes faster than ordinary steel.
5. Comparison with real heat-resistant steels
S355J0WP has no special high-temperature elements (Cr‑Mo, Ni, etc.), so its performance is similar to ordinary structural steel at high temperatures - far inferior to heat-resistant or boiler steels.
