Q390GJE is a high-strength low-alloy steel with excellent low-temperature high-rise performance. In China's low-temperature construction sector, the application of Q390GJE steel is becoming increasingly widespread. Its main performance indicators are as follows:

1. Tensile Strength: Q390GJE steel demonstrates high stability in tensile strength under low-temperature conditions. According to relevant standards, the tensile strength of Q390GJE steel should not be less than 400 MPa. In practical applications, the tensile strength of Q390GJE steel often exceeds 450 MPa, providing excellent load-bearing capacity in low-temperature environments.

2. Low-Temperature Toughness: Q390GJE steel exhibits good low-temperature toughness under cold conditions. Low-temperature toughness refers to the material's ability to withstand impact loads in low-temperature environments. The low-temperature toughness of Q390GJE steel meets the requirements of relevant Chinese standards, ensuring structural stability in cold settings.

3. Weldability: Q390GJE steel has high weldability and is suitable for various welding processes. In low-temperature environments, its weldability is even more superior, contributing to the low-temperature performance of welded structures.

4. Corrosion Resistance: Q390GJE steel possesses certain corrosion resistance in low-temperature environments. Due to slower corrosion rates in cold conditions, Q390GJE steel can maintain its mechanical properties and structural stability over the long term.

5. Dimensional Stability: Q390GJE steel offers good dimensional stability in low-temperature environments. Under cold conditions, the linear expansion coefficient of the steel is small, which helps control dimensional changes in structures and ensures the stability of low-temperature buildings.

6. Seismic Performance: Q390GJE steel has excellent seismic performance, effectively reducing earthquake-induced damage to buildings in low-temperature environments.

In summary, Q390GJE steel exhibits outstanding high-rise performance at low temperatures and is widely used in low-temperature building structures. In practical engineering, selecting the appropriate specifications and welding processes for Q390GJE steel based on design requirements and usage conditions can ensure the safety and stability of low-temperature buildings.