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Production process of spiral submerged arc welded pipe
1. Both internal and external submerged arc welding are carried out by Lincoln Welding Machine, USA, so as to obtain stable welding specifications.
2. The welds after welding are inspected by on-line continuous ultrasonic automatic damage instrument, which ensures 100% coverage of non-destructive detection of spiral welds. If there are defects, alarm automatically and spray marking, production workers can adjust the process parameters at any time to eliminate defects in time.
3. Air plasma cutting machine is used to cut the steel pipe into single pieces.
4. After cutting into single steel pipe, each batch of steel pipes must have strict first inspection system to check the mechanical properties of welds, chemical composition, dissolution status, surface quality of steel pipes and non-destructive testing to ensure that the pipe-making process is qualified before being put into production.
5. The weld seam with continuous acoustic flaw detection mark is inspected by manual ultrasonic and X-ray. If there is any defect, it is repaired and then nondestructively inspected again until it is confirmed that the defect has been eliminated.
The butt weld of strip steel and the pipe where the T-joint intersects with the spiral weld are all inspected by X-ray television or photography.
7. Each steel pipe is hydrostatic tested, and the pressure is radial sealed. The test pressure and time are strictly controlled by the micro-computer detection device of steel pipe hydraulic pressure. The test parameters are printed and recorded automatically.
8. The end of the pipe is machined so that the verticality, groove angle and blunt edge of the end face can be accurately controlled.
9 Raw materials are strip coil, welding wire and flux. Strict physical and chemical tests are required before investment.
The head and tail of 10 strips are butted by submerged arc welding with single or double wires and repaired by automatic submerged arc welding after coiling into steel pipes.
Before forming, the strip is leveled, trimmed, planed, cleaned, conveyed and bent.
12. The pressure of the cylinder on both sides of the conveyor is controlled by the electric contact pressure gauge, which ensures the smooth conveying of the strip steel.
13. Externally or internally controlled roll forming.
Weld clearance control device is used to ensure that the weld clearance meets the welding requirements, pipe diameter, offset and weld clearance are strictly controlled.
