Galvanized square tube
welding method and the general low-carbon steel is the same: welding the first layer of welding in the weld, try to make the zinc layer and vaporization, evaporation and escape the weld, can greatly reduce the liquid zinc Stay in the weld. In the welding of the weld, the same layer in the first layer as much as possible so that the zinc layer melting and vaporization, evaporation and escape the weld, the method is the first part of the electrode forward out about 5 ~ 7mm or so, when the zinc layer melt and then return to the original position to continue to apply welding. And then welding and vertical welding, such as the use of short slag electrode such as J427, undercut tendency will be very small; if the use of front and rear transport technology, but also can be defect-free welding quality.
Welding process control of the pipe before the preparation of welding with the general low-carbon steel is the same, need to pay attention to is to carefully handle the groove size and the nearby galvanized layer. For the penetration, the groove size should be appropriate, generally 60 ~ 65 °, to leave a certain gap, usually 1.5 ~ 2.5mm; in order to reduce the penetration of zinc on the weld, before welding, the groove can be galvanized Layer after cleaning and then welding. In the actual supervision work, the use of a concentrated groove, not leaving the blunt edge technology for centralized control, two welding process, reducing the possibility of non-penetration. The electrode should be based on galvanized square tube of the base material selection, the general low-carbon steel due to ease of operation, the choice of J422 is more common.