In the arc welding process from top to bottom and the all-position welding process from top to bottom, the welding speed is fast, the weld appearance is good, and the welding quality is good, which can save welding materials and reduce labor intensity. A common manual arc welding is more widely used in all-position welding of large-diameter long-distance pipelines. Electricity has certain promotion value in the construction of low-weld large-diameter thin-walled pipes.


During the welding process, the appropriate welding current, electrode angle and welding speed are usually selected, and the welding is completed by straight pulling or suppressing the arc swing. Ordinary welding electrodes are prone to the problem of dripping molten iron and slag, and the use of special welding electrodes for pipes and strict implementation of welding specifications can solve these problems. The cellulose type electrode has less welding slag, large arc force, and sufficient rigidity to prevent slag dropping and penetrating arc. It is especially suitable for thick-walled containers and welded steel pipe bottoming, which can eliminate the rooting operation, thereby improving work efficiency and improving work. Condition, but due to its higher. H welding has a large amount of hydrogen, so the domestic high-pressure pipeline welding current is usually welded with a cellulose electrode base and a low-hydrogen electrode and a filler cap surface.


Proper tube set and tack welding are important factors in ensuring the quality of the weld. Good soldering on the back is an important factor. The locating weld is part of the formal weld and requires not only profiled side welds but also weld quality. The length of the tack weld is 20 mm and the thickness is about 3 mm. Both sides of the weld should be ground to a gentle slope to facilitate the joint.


It is important to use the correct angle next to the welding electrode. The bottom welding, filling and capping angles are basically the same, but the arc length and conveying form are different. When the weld is close to the weld, the weld is controlled by the length and width. The main transport forms are arc, arc and arc. Note that the wrong position should be opened.