1. Welding connection
Welding is through the heat generated by the arc, so that the welding rod and weldment local melting. After cooling condensation into a weld, so that the weldment connected into one. Its advantages are: any form of components can be connected directly without weakening the cross-section of the components. It has the advantages of economical materials, simple structure, convenient manufacturing and processing, large connection stiffness, good sealing performance, automatic operation and high production efficiency. The disadvantage is that the heat affected zone of the steel near the weld is formed due to the high temperature of welding, which leads to the local material brittleness. During the welding process, the sample material is subject to uneven high temperature and cooling, resulting in the welding residual stress and residual deformation of the structure, which has a certain impact on the bearing capacity, stiffness and service performance of the structure. In addition, due to the high stiffness of welded steel structure, once local cracks occur, they are easy to expand to the whole, especially brittle fracture at low temperature. Moreover, the plasticity and toughness of welding are poor, which may cause defects during blasting and reduce the fatigue strength.
2. Rivet connection
Rivet connection is to insert a rivet with a prefabricated rivet head at one end into the rivet hole of the connected component, and press the other end into a closed rivet head by using a rivet gun or a riveting press, so that the connector is clamped by the rivet to form a firm connection. Rivet connection is characterized by reliable force transmission, good plasticity and toughness, and easy inspection and guarantee of quality plate. It can be used for heavy structure bearing dynamic load. However, it is rarely used at present due to its complex structure, steel and labor costs, poor working conditions and high cost.
3. Bolted connection
Bolt connection can be divided into ordinary bolt connection and high strength bolt connection. The advantages of bolt connection are: simple construction technology, convenient installation, especially suitable for site installation and connection. Its disadvantages are: the opening has a certain effect on the cross-section of the component, and the connected plates need to overlap each other or set up splicing pieces and other connectors. Therefore, it uses more materials than welding. In addition, the bolt connection needs to make holes in the plate, which increases the working position.
