Pipes are an indispensable part of various equipment, and pipes are widely used in petroleum, chemical and various devices and equipment. The quality of pipeline welding directly affects the normal operation of the equipment. Electrode arc welding of pipelines: Electrode arc welding of pipelines is currently the most commonly used welding method in general factories. It is a method of melting the pipe wall and electrode by manual operation, mixing to form a molten pool and solidifying to form a weld. Electrode arc welding equipment is simple, flexible and easy to apply, and is suitable for welding small diameter pipes, thin wall pipes and narrow pipes. Electrode arc welding can be used in any space and location. Rotary welding of pipelines: When processing pipelines in prefabricated plants, rotary welding is generally used, which is easy to operate and has high productivity. Pipe welding quality is closely related to butt and spot welding.
Pipe butt welding and tack welding: The specification of pipeline butt welding shall comply with the relevant standards of national enterprises. At the same time, the flatness of the end face of the groove should be less than 0.5 mm, and the dislocation of the joint assembly should not be greater than 1 mm. For small-diameter pipes, it is only necessary to position welding on the symmetrical sides of the pipe. For large-diameter pipes, three or more welds can be spot welded, and the size of the spot welds should be determined. When the thickness of the pipe wall is less than or equal to 5 mm, then the thickness of the welding point is 2.5-3 mm, if the thickness of the pipe wall is greater than 5 mm, the thickness of the welding point is about 4 to 5 mm, and the length of the spot welding is about 20-30 mm mm, in order to facilitate the penetration of the joint, both ends of the solder joint must be made into a gentle slope shape. Root Welding: shimless tube turn welding. In order to make the root easy to penetrate, the range of the strip should be selected in the vertical welding position. The method of operation can be straight or slightly wobbly crescent. If the gap between the butt joints is large, the arc extinguishing method can be used for welding. For thick-walled pipes, sometimes turning is laborious. At the same time, in order to prevent cracks at the root of the joint due to vibration during rotation, and to facilitate operation, the pipe should be placed on a flat turntable before butting. When soldering, preferably before turning once. At the same time, the weld must have sufficient strength, and the distance between the two fulcrums close to the joint should not exceed 1.5-2 times the pipe diameter.
