Below is a clear, engineering‑style summary based on typical performance of high‑strength weathering steels Q460NH:
1. Room temperature (20°C)
Yield strength ≥ 460 MPa (standard minimum)
Actual production value is usually around 480–550 MPa
2. 100°C
Yield strength decreases slightly
Approximately 90%–95% of room‑temperature value
Still very close to original strength
3. 200°C
Yield strength drops more noticeably
About 75%–85% of room‑temperature value
Still usable for non‑critical structures, but design margin reduces
4. 300°C
Significant softening occurs
Only 60%–70% of original yield strength
No longer reliable for load‑bearing structural members
5. Above 350–400°C
Yield strength falls rapidly to less than 50% of room temperature
Creep and plastic deformation become dominant
Q460NH is not suitable for service
