Basic characteristics of Q345B square tube

2025-09-05 11:32:32

　　The main components of Q345B square tube include carbon, silicon, manganese, phosphorus, sulfur and other elements, among which the carbon content is moderate, ensuring the balance of strength and toughness of the material. Compared with other ordinary carbon steel square tubes, Q345B has higher yield strength and tensile strength, and can withstand greater loads. Q345B square tube has good welding performance and is suitable for various welding processes, such as arc welding, gas shielded welding, etc. It is not easy to crack or deform after welding.

　　In terms of weather resistance, Q345B square tube also performs well. Compared to ordinary Q235 square tubes, Q345B is less prone to rusting in humid or high temperature environments, making it suitable for outdoor structures. However, compared with stainless steel square tubes, there is still a certain gap in their corrosion resistance, so additional anti-corrosion treatment may be required in some highly corrosive environments.

　　The production of 345B square tubes usually adopts hot rolling or cold bending forming processes. Hot rolled square tubes are produced through high-temperature rolling, with uniform internal structure and stable mechanical properties, suitable for withstanding high pressure or impact loads. Cold bent square tubes are formed by bending and welding cold-rolled steel strips, with a smooth surface and high dimensional accuracy, but the strength of the welded parts may be slightly lower than that of hot-rolled square tubes.

　　In terms of quality control, Q345B square tube needs to comply with relevant national standards to ensure that the chemical composition, mechanical properties, and dimensional deviations meet the standards. Ultrasonic or eddy current testing will also be conducted during the production process to eliminate internal defects.

　　Due to its strength and processability, Q345B square tube has a wide range of applications. In the field of architecture, it is commonly used for steel structure frames, stair handrails, and roof supports; In mechanical manufacturing, it can be used for equipment brackets, conveyor tracks, etc; In bridge engineering, it is used for temporary support structures or auxiliary components.