The square tube is often used in various building structures and engineering structures, such as house beams, bridges, transmission towers, lifting transport machinery, ships, industrial furnaces, reaction towers, container frames, and warehouse shelves The construction industry plays a very important role. It is a topic that the majority of architects and building materials dealers are always concerned. So how can we improve the welding of the square tube?
The square tube is also known as square and rectangular cold -curved empty heart steel, referred to as square tube and tube tube, codenamed F and J, respectively.
1. The allowable deviation of the wall thickness of the square tube. When the wall thickness is not greater than 10mm, it must not exceed the positive and negative of the nominal wall thickness 10%. When the wall thickness is greater than 10mm, it is 8%of the wall thickness. Except for wall thickness.
2. The general delivery length of the square tube is 4000mm-12000mm, mostly 6000mm and 12000mm. The square tube allows the delivery of short -scale and non -fixed -ruler products with no less than 2000mm, and can also be delivered in the form of interface. The weight of short -foot and non -fixed -ruler products does not exceed 5% of the total delivery volume, and the cubes with a theoretical weight of more than 20kg/m shall not exceed 10% of the total delivery volume.
3. The curvature of the square tube must not be greater than 2mm per meter, and the total curvature must not be greater than 0.2%of the total length.
The square tube welding is processed and connected to the tinguard according to the requirements of the process, and the gap stitching is reserved. The design of the welding joint is a relatively weak link in the welding project. The form of a slope plays a very important role in controlling the quality of the welding seam and the quality of welding structure manufacturing.
The process requirements are that the first layer of welding must be welded to ensure good back forming, welding current, arc voltage, wire delivery speed and welding speed. The welding deformation produced from the middle to the two sides is smaller than the direct welding, which is conducive to the decentralization and release of stress, and avoid complex stress in welding. The narrow plastic deformation zone formed by the welding of the welding of the direct swing is only once, and due to the continuous swing welding, the heat input volume is large, the heating area is large, and the plastic deformation area caused by compression is large, so the shrinkage and deformation after welding are large.
When the segmented jump welding, each layer of the section is small, the required heat is small, and each layer is divided into several sections to jump welding. Each section is basically re -established on the cold steel plate. Every time, a narrow plastic deformation area appears, so the average width of the plastic deformation zone is smaller than the corresponding layered straight through welding, and the vertical contraction is also smaller. Compared with the swing welding deformation that is filled once in a row, it is smaller.
