How to weld galvanized steel pipes

First, can galvanized steel pipe fittings be welded?
Galvanized steel pipes are common in daily life. They are generally used to transport low-pressure fluids such as gas and heating. They can also be used for trestle pipe piles, support frame pipes for mine tunnels, oil well pipes in oil fields, oil pipelines, etc., so can galvanized steel pipe fittings be welded? Generally speaking, galvanized steel pipe fittings can be welded. The galvanized layer of ordinary galvanized steel pipes is relatively thin, and ordinary electric welding or gas-shielded welding is used. Among them, gas-shielded welding is mainly suitable for situations where it is not convenient to grind and welding with a galvanized layer is required; if the galvanized layer is thick, you can consider using welding rod argon arc welding.

Second, how to weld galvanized steel pipes
Galvanized steel pipes are corrosion-resistant, have a long service life, and are relatively inexpensive, so they are widely used. When welding galvanized steel pipes, we must pay attention to the correct galvanized steel pipe welding method and some matters that need attention:
1. Before welding: The pre-welding preparation of galvanized steel is the same as that of general low-carbon steel. It is mainly to deal with the groove size and the nearby galvanized layer. The groove size is generally 60-65°, leaving a certain gap, generally 1.5~2.5mm; before welding, to reduce the penetration of zinc into the weld, the galvanized layer in the groove should be removed.
2. When welding: The welding technique adopts centralized groove beveling, and the process of not leaving blunt edges is centralized for control. The two-layer welding process reduces the possibility of incomplete penetration. When welding, you should also pay attention to the following:
(1) When welding the first layer of multi-layer welds, try to melt the zinc layer and make it vaporize and evaporate to escape the weld, which can greatly reduce the liquid zinc left in the weld.
(2) When welding fillet welds, try to melt the zinc layer in the first layer and make it vaporize and evaporate to escape from the weld. The method is to first move the end of the electrode forward about 5~7mm and then return to the original position to continue welding forward after the zinc layer is melted.
(3) When welding horizontally and vertically, it is recommended to use short slag electrodes such as J427, so that the edge biting tendency will be small; the forward and backward reciprocating electrode technology is used to improve the welding quality.
3. After welding: After welding the galvanized steel pipe, the galvanized layer at the welding point must be polished off, otherwise it will cause bubbles, sand holes, false welding, and other problems, and will also make the weld brittle and reduce rigidity.