Production process of spiral submerged arc welded steel pipe/spiral submerged arc welded steel pipe

Spiral steel pipe is a kind of spiral seam steel pipe, which is made of strip coil as raw material and is often extruded and welded by automatic double-wire double-sided submerged arc welding process.

1) Raw materials are strip coil, welding wire and flux. Strict physical and chemical tests are required before investment.

2) Submerged arc welding with single or double wires is used for butt joint of strip head and tail, and automatic submerged arc welding is used for repair welding after coiling steel pipe.

3) Before forming, the strip is leveled, trimmed and planed, and the surface is cleaned, conveyed and bent.

4) The electric contact pressure gauge is used to control the pressure of the cylinder on both sides of the conveyor to ensure the smooth conveying of strip steel.

5) Both internal and external welding are performed by single or double wire submerged arc welding with Lincoln Welding Machine, USA, so as to obtain stable welding specifications.

6) Weld clearance control device is used to ensure that the weld clearance meets the requirements of welding, pipe diameter, offset and weld clearance are strictly controlled.

7) Externally or internally controlled roll forming.

8) The welds after welding are inspected by on-line continuous ultrasonic automatic damage instrument, which ensures 100% coverage of spiral welds for non-destructive detection. If there are defects, alarm automatically and spray marking, production workers can adjust the process parameters at any time to eliminate defects in time.

9) Air plasma cutting machine is used to cut the steel pipe into single pieces.

10) After cutting into a single steel pipe, each batch of steel pipes must undergo 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.

11) The end of the pipe is machined so that the verticality, groove angle and blunt edge of the end face can be accurately controlled.

12) The tube where the butt weld of strip steel and the T-joint intersected with the spiral weld are all inspected by X-ray television or photography.

13) After hydrostatic test, the pressure of each steel pipe is sealed radially. 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.

14) The weld seam with continuous acoustic flaw detection marks is inspected by manual ultrasound and X-ray. If there are defects, after repair, the weld seam is subjected to non-destructive inspection again until the defects are confirmed to have been eliminated.