Q390A is a low-alloy high-strength structural steel specified in China's national standards, characterized by its high strength, excellent weldability, and formability. It is widely used in engineering structures subjected to high loads.
1. High-Rise Buildings and Bridge Engineering
Ultra-high-rise steel structure columns and lateral-force-resisting trusses: For instance, a 400-meter-class skyscraper employs Q390GJC-Z35 (thickness: 60–100 mm), utilizing TMCP + tempering processes to ensure Z-direction performance (ψZ ≥ 35%) and meet seismic design requirements.
Long-span bridge box girders, pylons, and connection nodes: In the Hong Kong-Zhuhai-Macao Bridge project, over 80,000 tons of Q390E steel were used in critical bridge components, guaranteeing toughness at -30°C.
2. Energy and Power Facilities
Wind turbine towers (sections above 80 m height): Q390NE steel meets impact toughness requirements at -40°C and, when combined with double-wire submerged arc welding (SAW) technology for flange circumferential seams, enhances welding efficiency and quality.
Nuclear power plant containment steel liners: Q390D steel is utilized in the "Hualong One" nuclear power station, satisfying stringent requirements for seismic Category I components.
3. Construction Machinery and Heavy Equipment
Crane booms and excavator platforms: The fatigue resistance and dynamic load-bearing capacity of Q390A steel make it suitable for key components in heavy machinery.
Mining dump truck frames and military armored vehicle chassis: The addition of microalloying elements such as Nb, V, and Ti enhances material strength and wear resistance.
