Q390E steel plate is a low-alloy high-strength structural steel, belonging to the steel series specified by the Chinese national standard GB/T 1591-2018. The "E" in the grade indicates that the material has excellent low-temperature toughness, typically requiring impact testing at lower temperatures to ensure the reliability and safety of the material in low-temperature environments.

Low-Temperature Welding Characteristics:

1. Welding Material Selection: Due to the excellent low-temperature toughness of Q390E steel plate, welding materials suitable for low-temperature environments must be selected to ensure that the weld metal also has sufficient toughness.

2. Preheating Treatment: When welding Q390E steel plate in low-temperature environments, preheating treatment may be necessary to reduce thermal stress and the risk of cold cracking during the welding process.

3. Welding Process: Low-temperature welding should adopt appropriate welding process parameters, including welding current, voltage, welding speed, etc., to ensure weld quality.

4. Post-Weld Heat Treatment: After welding is completed, post-weld heat treatment may be required to eliminate welding stress and improve the toughness of the weld metal.

5. Welding Inspection: Welding quality inspection in low-temperature environments is more stringent, requiring non-destructive testing methods to ensure the weld is free of defects.

Low-Temperature Application Fields:

1. Oil and Gas Industry: Q390E steel plate is suitable for low-temperature environments in oil and gas transmission pipelines, storage tanks, etc.

2. Chemical Equipment: Low-temperature chemical equipment and containers that need to withstand both low temperatures and chemical corrosion.

3. Shipbuilding: Ship structures face low-temperature environments during polar navigation. Q390E steel plate can be used for hull structures and offshore platforms.

4. Construction Engineering: Building structures in cold regions, such as bridges and high-rise buildings, need to consider the impact of low temperatures on material performance.

5. Pressure Vessels: Low-temperature pressure vessels used for storing and transporting liquefied gases require materials with good low-temperature toughness.

6. Polar Exploration Equipment: Polar exploration and scientific research equipment, such as ice drilling equipment and polar vehicles, need to operate in extreme low temperatures.

In practical applications, the low-temperature welding and application of Q390E steel plate require comprehensive consideration of the material's mechanical properties, welding processes, structural design, and environmental factors. It is recommended to fully communicate with material suppliers, welding engineers, and structural engineers before design and construction to ensure the safety and reliability of the project. At the same time, relevant standards and specifications should be followed, and strict quality control and performance testing should be conducted.