Large-diameter stainless steel pipes are increasingly popular in the petrochemical industry, coal slurry transportation, steel structure construction, etc. due to their high pressure resistance, low resistance, cold resistance, corrosion resistance, and convenient installation and maintenance. A warm welcome from the manufacturing industry.
The main production process of large-diameter stainless steel pipes is as follows:
1. Plate detection: After the thick steel plates used to produce large-diameter steel pipes enter the production line, the full plate is first carried out. Ultrasonic testing;
2. Edge milling: Use the edge milling machine to perform double-sided cutting on both edges of the thick steel plate to achieve the specified plate width, plate edge flatness and weld shape;
3. Pre-bending: Use a pre-bending machine to pre-bend the edge of the plate so that the edge of the plate has a refractive index that meets the requirements;
4. Forming: First, pre-bend the plate on the JCO forming machine One half of the final steel plate is stamped several times and rolled into a "J" shape, and then the other half of the steel plate is similarly bent and rolled into a "C" shape, finally forming an open "O" shape.
5. Pre-welding: join the formed steel pipes and use gas shielded welding (MAG) for continuous electric welding;
6. Internal welding: use longitudinal multi-wire buried Arc welding (up to four wires) is performed on the inner side of the straight seam steel pipe;
7. External welding: tandem multi-wire submerged arc welding is used on both sides of the straight seam submerged arc welded steel pipe. Electric welding;
8. Ultrasonic inspection I: 100% inspection of internal and external welding of straight seam welded steel pipes and butt welds on both sides;
9. X-ray inspection I: Carry out 100% X-ray industrial television inspection of internal and external welding, and use image processing systems to ensure the sensitivity of flaw detection;
10. Diameter expansion: Expand the diameter of the length of submerged arc welded straight seam steel pipes To improve the specification accuracy of steel pipes and improve the distribution of thermal stress in steel pipes;
11. Pressure test: The expanded steel pipes are tested one by one on a hydraulic testing machine to ensure that the steel pipes meet the specifications. According to the specified test pressure, the equipment has automatic saving and storage functions;
12. Chamfering: The steel pipes that meet the standards will be processed at the pipe end to achieve the specified pipe end weld specifications;< /p>
13. Ultrasonic inspection II: Carry out ultrasonic inspection one by one again to check the defects that may occur after expansion and pressure of the straight seam welded steel pipe;
14. X-ray inspection Ⅱ: Carry out X-ray industrial television inspection and take pictures of pipe end welding on steel pipes after diameter expansion and compression tests;
15. Pipe end magnetic particle inspection: Carry out this inspection to detect pipe end defects;< /p>
16. Anti-corrosion and coating: After meeting the standards, the steel pipes will be anti-corrosion and coating according to customer requirements.