Large steel pipe welding

In the large diameter pipe welding process, the workpiece and form a molten solder is melted region, the connection between the material cooled and solidified after the formation of the pool.

Large diameter thick-walled tube usually need to apply pressure in welding process. Welding energy source, there are many, including a gas flame, electric arc, laser, electron beam, friction and ultrasonic.

1, A board probe: used to manufacture large diameter submerged arc welding of steel plates after entering the production line, the first full-board ultrasonic testing to check whether there are internal defects plate.

2, Milling: Milling machine through the two-sided edge of the milling plate, so as to meet the requirements of the target diameter of the plate width, parallel to the edge of the plate and the groove shape, ready for soldering.

3, Pre-curved edges: Use pre-bent plate edge pre-bending machine, the plate has to meet the requirements of the curvature of the edge, so that the size of the pipe forming the appearance of more and more precise.

4, Forming: On the JCO forming machine after the first half of the pre-bent steel after several multi-step pressed, pressed into a "J" shape, and then the other half of the same bent steel plate, pressed into a "C" shape, the final form The opening "O" shape, which is the origin JCOE process.

5, pre-welding: straight seam welded steel pipe seam so after forming and using carbon dioxide gas welding (MAG) continuously welded steel pipe forming.

6, inner weld: the use of multi-wire submerged arc column (up to four wire) on the inside straight seam welded steel pipe.

7, Weld: Adopt multi-wire submerged arc welding on the outside tandem LSAW steel pipe welding.

8, ultrasonic testing:. According to the standard of straight seam welded steel pipe inside and outside the weld metal and the weld heat affected zone on both sides of 100% of the ultrasound examination and recorded.

9, X-ray inspection:. Internal and external welds 100% X-ray industrial TV inspection, using an image processing system to ensure compliance with the detection sensitivity testing requirements.

10, for expansion: the full length of straight pipe joints SAW enlarged diameter to increase the dimensional accuracy of the steel pipe, steel pipe and to improve the distribution of stresses.

11, hydraulic test: On the hydraulic test machine for steel after expanding by-root test to ensure that the steel pipe to test pressure requirements of the standard, the machine has an automatic recording and storage capabilities;

12, chamfering: The steel pipe inspection conducted after the end of processing, to the pipe end beveling size requirements;

13, Ultrasonic Inspection: root again by ultrasonic testing to check for straight seam welded steel pipe in expanding defects that may arise after the water pressure;

14, X-ray inspection: expanded diameter of the steel pipe after hydrostatic testing and industrial X-ray inspection and tube end welds TV film;

15, pipe end magnetic particle inspection: this check to detect defects in the pipe ends;

16, anti-corrosion and coating: after passing the pipe and coatings for corrosion protection in accordance with user requirements.

17, marks: the appearance of the pipe size, length, material, performance standards, such as marked on the pipe.