What should we procure now for the old Q345?
Prioritize Q355 (mandatory upgrade according to national standards), with equivalent or superior performance, and can directly replace it.
How much more expensive is Q345E than D?
5-10% more expensive due to higher low-temperature impact requirements and a higher scrap rate.
Can it replace Q235?
Yes, but it's not economical. Q345 has higher strength, allowing for thinner cross-sections (e.g., Q235 10mm → Q345 8mm), reducing weight.
What is its lifespan?
With normal corrosion protection and reasonable design, the lifespan is ≥50 years. The design reference period for buildings/bridges is typically 50 years.
What is the allowable design stress?
According to GB 50017: Q345: 215MPa (t≤16mm), 205MPa (16–35mm) Q355: 225MPa (t≤16mm).