Structural characteristics

Light steel structures usually use Q345 and Q235 steel, and most of them are Q345 steel. Q345 steel, as the most commonly used and mature low-alloy high-strength structural steel, has excellent performance and good weldability. In addition to part of the column bottom plate, the thickness of the web and wing plate is basically 4-20mm thin plate, which is the most favorable thickness range for the welding process. Light steel structure generally does not use box type, cross type structure, most of the members are H-section. Due to the characteristics of economy, force and structure, rolled H-beam steel is generally not used, and most of them are welded H-beam steel. For H-type solid belly beam-column structure, it is easy to realize the automation of welding and assembly. However, in addition to the sandwich beam and part of the side column, the middle column is the same section, most of the components are in the form of variable section, which also puts forward higher requirements for the automation of welding.

Cutting method

Gate-type multi-head flame cutting is the main cutting method of wing strip. New gas of propylene, propane and LPG have gradually replaced acetylene. Web because the plate thickness is thin, and most of the shape is wedge-shaped, usually using CNC plasma cutting method. Using oxygen plasma cutting method, cutting speed is fast, cutting quality is good, but the requirement of consuming electrode is higher. The cutting quality of the web has a great influence on the welding quality of the component. Due to the thin thickness of the plate, the deformation or residual stress after cutting will lead to the wavy deformation of the web. The quality of cutting edge will directly affect the welding and weld quality of fillet weld between web and wing.

Welding method

The welding process and production flow depends on the alignment of the H-shaped steel, the welding of the main welds between the web and the fins, and varies according to the alignment method, welding method and welding location. If the head moves or the workpiece moves; Horizontal position or ship shape position; Single head or double head; Monofilament or double filament, etc. Gas shielded welding is undoubtedly the most ideal welding method for dry sheet structure. Therefore, in addition to the submerged arc automatic welding of the plate, the rest of the plate welding is mostly gas shielded welding. In particular, argon-rich gas shielded welding is more suitable for light steel structures because of its good forming and small splash.