There are several precautions to keep in mind for the welding of steel structures
Steel structure in the welding process, there are many things to note, once ignored, it may lead to a big mistake. Today, Xiao Bian for your finishing steel structure welding process is often overlooked matters, do not careless.
Welding construction do not pay attention to choose the best voltage
Welding, whether it is primer, fill, cover, regardless of the size of the groove size, are selected the same arc voltage, it may not meet the requirements of the depth of penetration, melting width, resulting in undercut, stomata, splash and other defects.
Generally for different situations should choose the corresponding long arc or short arc, can get better welding quality and efficiency. Such as the bottom of the welding in order to get a better penetration, should be used short arc operation; steel structures filling or cover welding, in order to get a higher efficiency and width, you can increase the arc voltage.
Do not pay attention to control the arc length
Welding is not based on the groove form, the number of welding layers, welding forms, electrode models and other appropriate adjustment arc length. Due to improper use of welding arc length, it is difficult to obtain high quality welds.
In order to ensure the quality of the weld, welding generally use short arc operation, but according to different circumstances to choose the appropriate arc length to obtain the best welding quality, such as V-shaped groove docking, steel structures cornering the first layer should be used Short arcs to ensure penetration, and no biting phenomenon; the second layer can be slightly longer to fill the weld. Weld gap hours, it is appropriate to use short arc, the gap can be slightly longer when the arc, welding speed. Arc welding arc should be the shortest to prevent the molten iron downstream; vertical welding, horizontal welding in order to control the bath temperature, but also with a small current, short arc welding. In addition, no matter what the welding method, in the course of movement, we should always keep the arc length is basically the same, in order to ensure that the entire weld width and penetration of the same.
Requires penetration of the butt joint or angular butt joint weld foot size is not enough
T-shaped joints, cross fittings, corner joints and other requirements of the penetration of the butt joint or angle butt joint weld, steel structures the foot size is not enough, or designed to have fatigue testing requirements of the crane beam or similar components of the web and the upper wing edge Weld the foot size is not enough, will make the welding strength and stiffness are not up to the design requirements.
T-joints, cross fittings, corner joints and other requirements of the fusion of the welding joints, should be in accordance with the design requirements, steel structures there must be sufficient foot requirements, the general foot size should not be less than 0.25t (t for the connection of thinner Thickness). Designed to have a fatigue check the requirements of the crane beam or similar web and the upper flange connection weld the foot size of 0.5t, and should not be greater than 10mm, welding size tolerance of 0 ~ 4mm.