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Double submerged arc welding straight seam steel pipe
Jul 03, 2017

1. plate exploration: for the production of large caliber submerged arc welded steel pipe into the production line, first carried out full plate ultrasonic testing;

2. milling edge: double edge milling of the two edge of the steel plate is made by milling machine to achieve the required width of the plate, parallel edge of the plate and groove shape;

3., pre bending edge: pre bending machine plate edge pre bending, so that the edge of the plate has required curvature;

4. molding: in the JCO molding machine, first of all, the pre bending steel plate after more than half step stamping, pressing into "J" shape, and then the steel plate of the other half of the same bending, pressing into "C" shape, and finally form "open" "O" shape

5.: the pre welding of welded pipe seam forming and using gas welding (MAG) for continuous welding;

6.: welding by submerged arc weld (maximum five wire) welding in welded steel pipe inside;

7.: welding by submerged arc welding in longitudinal submerged arc welding pipe outside welding;

8. ultrasonic inspection: 1. Inspect the inner and outer weld seam of the straight welded pipe and the parent material on both sides of the weld seam 100%;

9. X ray inspection I: 100% X ray industrial television inspection of internal and external welds, using image processing system to ensure the sensitivity of flaw detection;

10. diameter expansion: the length of the submerged arc welded straight steel pipe is expanded to improve the dimensional accuracy of the steel pipe and to improve the distribution of the internal stress of the steel pipe;

11. hydraulic pressure test: in the water pressure test machine, the expanded steel pipe is tested by root to ensure the test pressure of the steel pipe meets the standard requirement. The machine has the function of automatic recording and storage;

12., chamfering: after the inspection of qualified steel pipe end processing, to achieve the requirements of the end of the pipe groove size;

13. ultrasonic examination II: again by root ultrasonic testing to check the straight seam welded pipe in the expansion of water pressure may be caused by defects;

14. X ray inspection II: X ray industrial television inspection and pipe end weld shooting are carried out on steel tubes after expanding and hydrostatic pressure test;

15. tube end magnetic particle inspection: this inspection is carried out to detect defects in the pipe ends;

16. anti-corrosion and coating: qualified steel pipe according to user requirements for corrosion protection and coating, zinc plating, etc..


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