The mechanical properties of Q355NH weathering steel plate show distinct temperature-dependent characteristics, with core indicators (strength, toughness, plasticity) changing regularly in different temperature ranges, as detailed below:
Low temperature range (-40℃ to room temperature)
Its mechanical properties remain stable with excellent toughness. There is no obvious drop in yield/tensile strength, and the Charpy V-notch impact energy is ≥34J at -20℃. Customized grades can maintain the same toughness even at -40℃ without cold brittleness, suitable for outdoor applications in frigid regions.
Medium temperature range (room temperature to 200℃)
All mechanical properties meet the design standards with no significant attenuation in strength, plasticity and rigidity. The elastic modulus remains stable at about 206 GPa, which is the core safe application temperature range of this steel.
High temperature range (＞200℃)
Properties deteriorate continuously: yield/tensile strength decrease linearly with rising temperature (a 20% drop at 300℃, 40% at 400℃). Meanwhile, high-temperature creep occurs, leading to easy deformation under load. Irreversible microstructure coarsening happens above 450℃, causing permanent loss of toughness and strength even after cooling.
