1、 Can galvanized steel pipes be welded?
Galvanized steel pipes are very common in daily life, generally used for transporting low-pressure fluids such as gas and heating. They can also be used for wharf pipe piles, support pipes in mining tunnels, oil well pipes in oil fields, oil pipelines, etc. Can galvanized steel pipes be welded? Generally speaking, galvanized steel pipes can be welded. The galvanized layer of ordinary galvanized steel pipes is relatively thin, and ordinary electric welding or gas shielded welding is used. Gas shielded welding is mainly suitable for situations where it is inconvenient to polish and requires welding with a galvanized layer; If the galvanized layer is thick, argon arc welding with welding rods can be considered.
2、 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, it is important to pay attention to the correct welding method and some precautions:
1. Pre welding: The pre welding preparation for galvanized steel is the same as that for general low-carbon steel, mainly by processing the groove size and the nearby galvanized layer. The groove size is generally 60-65 °, with a certain gap, usually 1.5-2.5mm; Before welding, in order to reduce zinc penetration into the weld seam, the galvanized layer inside the groove should be removed.
2. During welding: The welding process adopts a centralized bevel groove without leaving blunt edges, and the two-layer welding process reduces the possibility of incomplete penetration. When welding, the following points should also be noted:
(1) When welding the first layer of a multi-layer weld seam, try to melt the zinc layer as much as possible and allow it to vaporize and evaporate out of the weld seam, which can greatly reduce the residual liquid zinc in the weld seam.
(2) When welding fillet welds, try to melt the first layer of zinc and allow it to vaporize and evaporate out of the weld seam. The method is to first move the end of the welding rod forward by about 5-7mm, wait for the zinc layer to melt, and then return to the original position to continue welding forward.
(3) When welding horizontally or vertically, it is recommended to use short slag welding rods such as J427 to reduce the tendency for edge biting; Adopting reciprocating electrode technology to improve welding quality.
3. After welding: After welding galvanized steel pipes, the galvanized layer of the welding points must be polished off, otherwise it will cause problems such as bubbles, sand holes, false welding, and make the weld brittle, reducing rigidity.
