Q460NH is a high-strength weathering steel designed for ambient temperature service. Its strength changes with temperature as follows:
1. Below 100°C
Yield strength and tensile strength remain almost unchanged from room temperature.
No obvious softening; mechanical properties are stable.
Suitable for long-term continuous service.
2. 100°C – 200°C
Strength begins to slightly decrease (about 5%–10% lower than at room temperature).
The decline is moderate; the material still maintains most of its load-bearing capacity.
Short-term or intermittent service is acceptable, but long-term use at the upper end of this range is not ideal for critical structures.
3. 200°C – 300°C
Strength drops significantly, with yield strength potentially falling 15%–30% below room-temperature values.
Creep behavior gradually appears under sustained load.
The weathering patina starts to break down, forming loose oxide scale.
Not recommended for load-bearing structural use in this range.
4. Above 300°C
Severe softening occurs; strength decreases rapidly and continuously.
Microstructure stability is lost, leading to permanent degradation of mechanical properties.
Creep deformation and embrittlement become serious risks.
Q460NH cannot be used in this temperature range.
