1. structural features
Light steel structures are usually made of Q345 and Q235 steel, and most of them are Q345 steel. As the most commonly used and mature low alloy high strength structural steel, Q345 steel has good weldability and good weldability. Except for some column bottom plates, the web plate and wing plate thickness is basically 4-20mm medium plate, which is the most favorable thickness range for welding process. Lightweight steel structure generally does not use box type, cross type structure, most of the components are H type section. Due to the economic, mechanical and structural characteristics, rolling H steel is not generally used, and most of them are welded H steel.
It is easy to realize the automation of welding and assembly for the H type solid web beam column structure. But in addition to the sandwich beam and part of the side column, the middle column is equal section, most of the components are variable cross-section form, which also puts forward higher requirements for the automation of welding.
2. cutting method
Door type multi flame cutting is the main cutting method of wing plate opening, propylene, propane, LPG new type of gas has gradually replaced acetylene.
Because of the thin plate thickness and mostly wedge-shaped shape, the numerical control plasma cutting method is usually used. The oxygen plasma cutting method has the advantages of fast cutting speed and good cutting quality, but the requirement of consumable electrode is higher.
The cutting quality of the web has a great influence on the welding quality of the components. Because of the thinner plate thickness, the deformation or residual stress after cutting will cause the wavy deformation of the web. The quality of the cutting edge will directly affect the fillet weld and weld quality between the web and the wing plate.