Review Straight seam steel pipe according to the production process can be divided into high-frequency straight seam pipe and submerged arc welded straight seam pipe. The submerged arc welded straight seam steel pipe is divided into Uoe, RBE, Jcoe steel pipe and so on according to its different molding mode.
The following describes the most common high frequency straight seam pipe and submerged arc welded straight seam steel pipe forming process.
Submerged Arc welding Technology
1. Board: Used to make large-diameter submerged arc welded straight seam steel pipe after entering the production line, first of all plate ultrasonic inspection;
2. Milling edge: Through the milling machine to the two edges of the steel plate milling, to achieve the required plate width, plate edge parallelism and groove shape;
3. Pre-bending edge: The bending machine is used to bend the edge of the plate so that the edge of the plate has the curvature that conforms to the requirement;
4. Forming: In the Jco molding machine first will be curved after half of the steel plate after several steps into the stamping, pressure into the "j" shape, and then the other half of the steel plate bending, pressure into the "c" shape, finally formed the opening of the "o" shape
5. Pre-welding: After forming the straight seam welded pipe joint and the use of gas shielded welding (MAG) for continuous welding;
6. Internal welding: Longitudinal multi-wire submerged arc welding (up to four wire) is welded on the inside of straight seam steel pipe;
7. External welding: The longitudinal and multi wire submerged arc welding is used to weld the outer side of the straight seam submerged arc welded pipe;
8. Ultrasonic inspection Ⅰ: For the longitudinal seam welded steel pipe inside and outside welds and weld both sides of the base material for 100% inspection;
9. x-ray inspection Ⅰ: 100% x-ray Industrial TV inspection of internal and external welds, using image processing system to ensure the sensitivity of flaw detection;
10. Expanding diameter: The whole length of submerged arc welded pipe is enlarged to improve the dimension precision of steel pipe and to improve the distribution of stress in steel pipe;
11. Water pressure test: On the hydraulic testing machine for the steel pipe after the expansion of the root test to ensure that the steel pipe to meet the standard requirements of the test pressure, the machine has automatic recording and storage functions;
12. Chamfering: The pipe end is processed by the qualified steel pipe to reach the required pipe end groove size;
13. Ultrasonic inspection Ⅱ: Again by the root of the ultrasonic test to check the straight seam welded steel pipe in the expansion, water pressure may be caused by defects;
X-Ray Inspection Ⅱ: X-ray Industrial television inspection and pipe end weld filming of steel tubes after expanding and hydrostatic tests;
15. The Tube end Magnetic particle inspection: Carries on this examination to discover the tube end flaw; 16. Anticorrosion and coating: after qualified steel pipe according to user requirements for anti-corrosion and coating.