DSAW double-sided submerged arc welded pipe

Double submerged arc welding (DSAW) steel pipes come in two forms: straight seam and spiral welding, and can be used for various applications.

DSAW pipes can be specified as very large diameters and precise to internal or external dimensions. The unique feature of spiral welded steel pipes lies in their manufacturing process, which produces a spiral DSAW weld seam length of 155 feet.

The manufacturing of double submerged arc welded pipes first involves shaping the steel plate into a cylindrical shape. Then, the edges of the rolled plate are formed to create V-shaped grooves on the inner and outer surfaces of the joint position. Then, the pipe seam will be welded in a single pass on both the inner and outer surfaces using an arc welding machine. The welding arc is submerged by the flux. The advantage of this process is that the weld can penetrate 100% of the pipe wall and produce a very strong pipe bond.

How is DSAW double-sided submerged arc welded thick walled spiral steel pipe manufactured?

Spiral steel pipe is a spiral seam steel pipe made from strip steel coil and extruded by automatic double wire double-sided submerged arc welding.

(1) The raw materials are strip steel coils, welding wire, and flux. Strict physical and chemical testing is required before investing.

(2) The joint between the head and tail of the strip steel is welded using single or double line submerged arc welding. After being rolled into a steel pipe, automatic submerged arc welding is used for repair welding.

(3) Before forming, the strip undergoes leveling, trimming, planing, surface cleaning, conveying, and pre bending treatment.

(4) Electric contact pressure gauge is used to control the pressure of the cylinders on both sides of the conveyor to ensure smooth conveying of the strip.

(5) Adopting external or internal control roll forming.

(6) The weld seam gap control device is used to ensure that the weld seam gap meets the welding requirements and strictly controls the pipe diameter, misalignment, and weld seam gap.

(7) Both internal and external welding are carried out using American Lincoln welding machines for single or double line submerged arc welding to obtain stable welding specifications.

(8) The welded seams are inspected using an online continuous ultrasonic automatic flaw detector to ensure 100% non-destructive testing coverage of spiral welds. If there is a defect, it will automatically sound an alarm and spray a mark, and production workers can adjust process parameters at any time to promptly eliminate the defect.

(9) Use an air plasma cutting machine to cut steel pipes into individual pieces.

(10) After the first three steel pipes in each batch are cut into individual steel pipes, the first inspection system should be strictly implemented to check the mechanical properties, chemical composition, weld fusion status, and surface quality of the steel pipes. Non destructive testing should be carried out to ensure that the pipeline manufacturing process is qualified before it can be officially put into production.

(11) Parts with continuous ultrasonic testing marks on the weld seam are re inspected by manual ultrasonic and X-ray testing. If there are defects, non-destructive testing will be conducted again after repair until the defects are confirmed.

(12) The pipes with strip butt welds and D-shaped joints intersecting with spiral welds are inspected by X-ray television or photography.

(13) Each steel pipe undergoes a hydrostatic pressure test, and the pressure is sealed radially. The test pressure and time are strictly controlled by the steel pipe hydraulic microcomputer detection device. The test parameters will be automatically printed and recorded.

(14) The pipe end is machined to precisely control the perpendicularity, bevel angle, and blunt edge of the end face.

Spiral double welded pipe process

Double submerged arc welded spiral steel pipes are increasingly popular in industries such as oil and gas, mud transportation, and urban construction due to their high pressure resistance, low resistance, low temperature resistance, corrosion resistance, and easy installation and maintenance.

Spiral double welded pipe process

1、 Adopting the double submerged arc welding process, the deformation of the plate is uniform and small, the residual stress is large, and there are no scratches on the surface. The range of pipe sizes for processing pipe diameters and wall thicknesses is large and flexible, especially in the production of high-end steel thick walled steel pipes. Large diameter thick walled pipes have unparalleled advantages over other technologies and can meet users' requirements for pipe size;

The pre welding external welding (precision welding) process can be carried out at the optimal position for welding, which is not prone to welding quality defects such as welding deviation and incomplete penetration, and is easy to control;

Three integral mechanical expansion can effectively improve the dimensional accuracy of steel pipes, improve the distribution of stress in steel pipes, thereby avoiding damage caused by stress corrosion and facilitating on-site welding construction;

Four pairs of steel undergo 100% quality inspection to effectively detect and monitor the entire process of pipe production, ensuring the product quality of submerged arc welded pipes;

The entire production line equipment is connected to the computer data acquisition system, achieving real-time data transmission. The production process parameters and quality indicators are adopted by the central control room.

Welding advantages of double submerged arc welded straight seam steel pipes

Double submerged arc welding straight seam steel pipe is a new welding method invented in 1940. It is manually welded or slag protected at the same position and front, but this residue is not the electrode coating, but the melted flux.

The flux system consists of a funnel containing flux transported through a pipeline to the front part to be welded. The second difference is not between electrodes and wires, as wires can transmit continuously; Welding electrode, when we burn a welding electrode, we must throw out the electrode head, stop the operation, and then replace the electrode for welding.

After replacing the welding wire, the welding wire and welding wire are rented out by wire feeding to provide continuous welding wire. The welding wire is continuously fed in, and the welding wire covered with granular flux can melt under the ignition of the arc. The melting and evaporation of the welding wire, substrate, and some flux form a cavity arc, which burns stably in the cavity and is called submerged arc welding. The arc is buried in the internal cavity.

DSAW pipe application

We supply DSAW pipes to the following industries worldwide:

Petroleum industry, natural gas industry, filtration industry, refrigeration industry, refining industry, petrochemical industry, overseas processing and export industry, advantages of double submerged arc welding

Firstly, it is fully automated.

Secondly, it is carried out under submerged arc welding, with relatively strong heat exchange and protection performance, and relatively high welding quality;

Thirdly, the submerged arc welding arc is buried under the flux, allowing for the use of high current and high welding efficiency. This is currently the ongoing West East Gas Pipeline project in China.

Pipeline is a type of high-strength steel, and this prefabricated pipe section is first produced inside the factory and then transported to the site for welding. The welding process uses this type of pipeline for submerged arc welding in the factory, which has developed into double wire submerged arc welding and multi wire submerged arc welding.

Dsaw pipeline performance

Our technical team can assist you in developing pipeline projects to meet your overall system and budget requirements. Through our partners and affiliated companies, we can provide you with comprehensive solutions, from simple DSAW pipeline production to complete pricing including ID/OD coating, double-sided welding, and transportation.