Solution of welded pipe in electric welding

The method of welded pipe is as follows: firstly, the edge of the plate is probed, and after the steel plate used for manufacturing large-diameter submerged arc welded straight seam steel pipe enters the production line, the whole plate is first subjected to ultrasonic flaw detection. After edge milling, the two edges of the steel plate are double-sided milled by an edge milling machine to achieve the required plate width, plate edge parallelism and groove shape.

Pre-bending the edge of the plate with a pre-bending machine to make the edge of the plate have the required curvature. On the JCO molding machine, first, half of the pre-bent steel plate is pressed into a J shape through multiple processes, then the other half of the steel plate is pressed into a C shape, and finally an O shape with an opening is formed.

Seam welding and continuous welding of the formed straight seam welded steel pipe by gas shielded welding (MAG); Longitudinal multi-wire submerged arc welding (up to four wires) is adopted for the inner side of the straight welded steel pipe; Longitudinal multi-wire submerged arc welding is used to weld the outer side of longitudinal submerged arc welded steel pipe, thus completing pipeline welding.

Extended data

Welding mode of steel pipe

1, welded steel pipe

Also known as welded pipe, it is cut from steel strip into narrow steel strip, and then cold-worked into pipe with die. Then a special welder will weld a pipe joint. The external weld is polished and bright. Generally, the burr inside welded pipe is not perforated. Only the precision welded pipe has burrs inside.

Anti-corrosion points: welded steel pipe refers to the steel pipe with joints on the surface after being bent and deformed into a circle and a square with steel strip or steel plate. According to different welding methods, it can be divided into arc welded pipe, high-frequency or low-frequency resistance welded pipe, gas welded pipe, furnace welded pipe and Bundy pipe. According to the weld shape, it can be divided into straight welded pipe and spiral welded pipe.

Welded steel pipes are used in petroleum drilling, machinery, manufacturing and so on. Furnace welded pipes can be used as water pipes and gas pipes, and large-diameter straight welded pipes can be used for high-pressure oil and gas transportation. Spiral welded pipe is used for oil and gas transportation, pipe piles, piers, etc. Welded steel pipe has lower cost and higher production efficiency than seamless steel pipe.

2. Straight welded pipe

It is made of steel plate or steel strip by bending and welding. According to the weld form, it is divided into straight welded pipe and spiral welded pipe. According to the purpose, it can be divided into ordinary welded pipes, galvanized welded pipes, oxygen-blown welded pipes, silk sleeves, metric welded pipes, idler pipes, deep well pump pipes, automobile pipes, transformer pipes, welded thin-walled pipes, welded special-shaped pipes and spiral welded pipes.

3. Ordinary welded pipe

Usually, welded pipes are used to transport low-pressure fluids. Made of steel Q 195A, Q2 15A and Q235A.

. It can also be made of other low carbon steels that are easy to weld. Steel pipes have to undergo water pressure, bending, flattening and other experiments, which have certain requirements for surface quality. Usually the delivery length is 4- 10m, and it is often required to deliver according to the length (or double the length).

The specifications of welded pipes are expressed in nominal caliber (millimeters or inches). The nominal caliber is different from the actual situation. There are two kinds of welded pipe wall thickness: ordinary steel pipe and thickened steel pipe, and steel pipe is divided into threaded pipe end and non-threaded pipe end. Table 6- 17 shows the dimensions of welded steel pipes.

Reference source: Baidu Encyclopedia-Welded Pipe Production Line

Reference source: Baidu Encyclopedia-Welding