Is high frequency welded pipe the best way to weld steel pipes?

Steel pipes can be divided into two categories according to production methods, one is seamless steel pipes, the other is welded steel pipes, welded steel pipes are straight seam welded pipes, and welded steel pipes can be further divided into high-frequency welded pipes and double-sided buried pipes according to welding methods. Arc welded pipe.

First of all, let us focus on high-frequency welded pipes. The diameter of high-frequency welded pipes is usually very small and does not need to pass through the welding wire, so the possibility of cracking when expanding is very small. In terms of welding speed, for smaller outer diameters, such as those below 1 inch, the speed can be as high as 200 meters per minute. There are usually two crimping methods, one is welding and the other is fusion welding. High-frequency welding is the first welding method. From the processing point of view, welding welded pipes is mainly to bend the steel plate into a cylinder, and then weld it into shape. The method is simple and efficient.
According to the principle of electromagnetic induction and the skin effect, proximity effect and eddy current thermal effect of AC charges in the conductor, the steel at the welding edge is heated and melted, and then squeezed by a roller to realize the intergranular connection of the butt weld, so as to achieve the purpose of welding. High-frequency welding is a kind of induction welding, which has the advantages of no welding filler, no welding spatter, narrow welding heat-affected zone, beautiful welding shape, and good welding mechanical properties. It has been widely used in steel pipe production.

The high-frequency welding of steel pipes uses the skin effect and proximity effect of alternating current. After the steel (strip steel) is rolled and formed, a circular tube blank with a broken section is formed, and one or a group of resistors (magnetic rods) are rotated near the center of the tube blank induction coil, and the resistor and the tube blank opening form a Electromagnetic induction circuit. Under the action of skin effect and proximity effect, the edge of the opening of the tube billet produces a strong and concentrated heat effect, so that the edge of the weld seam is rapidly heated to the temperature required for welding. After being squeezed by the pressure roller, the metal melt realizes intergranular bonding and cooling Finally, a firm butt weld is formed.
The double-sided submerged arc welded pipe needs to use welding wire, the weld seam is much longer than the straight seam pipe, and the production efficiency will be much lower, but it may be stronger in terms of strength and compression resistance. It also has other advantages, such as a good realization of automation. Secondly, based on the relatively strong performance in two aspects, the welding quality of the final product is higher, one is heat exchange, and the other is protection performance.

The production process based on high-frequency welded pipe is relatively simple, so relatively speaking, the production efficiency of high-frequency welded pipe is higher, but on the basis of the continuous development of double-sided submerged arc welded pipe, its production efficiency has also been further improved. In conclusion, both welding methods have advantages and disadvantages. High-frequency welded pipe has the advantages of small cracking possibility, fast welding speed, simple welding forming method, and high production efficiency. The main advantages of double-sided submerged arc welded pipes are automation and high welding quality. In practical applications, which welding method should be selected also needs to be analyzed according to specific conditions.