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When welding steel pipe, the nozzle should be prepared as follows:

1.Clear the rust, dirt and grease at the interface.
2.When the steel pipe is welded or mechanically cut, the cross section should be straightened to ensure the concentricity of the pipe welding. Cut the burrs or attachments before welding.
3.When the three holes in the pipeline when the hole should be carried out repair, the tube should be removed clean residue, saddle-shaped opening height should not be less than 1/2 of the diameter.
4.In order to ensure that the pipe wall during the welding process can be fully welded, the nozzle should be made groove, groove form can be selected according to the thickness of the wall.
6.5.° blunt edge of 1 to 2, counterpart The gap is 1 ~ 3.
7.The groove can be machined with gas cutting (artificial groove) or groove machine. The groove after machining should remove the slag and iron oxide and trim with steel file until the metallic luster is exposed.
8.Different wall thickness of the pipe butt welding, the thickness of the two pipe walls shall not exceed 10% of the smaller wall thickness, up to no more than 3mm (referring to the difference between the two wall thickness), or deal with the thickness of the tube for processing.
9.In the welding, the distance between the adjacent two pipe joints shall not be less than 200mm, the minimum should not be less than the nominal diameter of the pipeline.