1. Raw material testing, strip steel coil production method and normal temperature extrusion molding production process. The raw materials, namely steel coil, welding wire, and flux, must undergo strict physical and chemical inspection before being put into use.

2. For flattening treatment, the steel coil or hot-rolled coil plate is fed into the welded pipe unit. After rolling with multiple rollers, the strip is gradually rolled up to form a round tube blank with an opening gap. Adjust the reduction amount of the extrusion roller. Control the weld gap to 1-3mm and align both ends of the weld.

2. For the head-to-tail butt jointing of steel strips, single-wire or double-wire submerged arc welding is used, and automatic submerged arc welding is used for repair welding after being rolled into steel pipes. Before forming, the strip steel is straightened, trimmed, planed, surface cleaned, transported and pre-bent. Electric contact pressure gauges are used to control the pressure of the cylinders on both sides of the conveyor to ensure stable conveying of the strip steel.

3. Forming (using external control or internal control roller type), weld gap control device to ensure that the weld gap meets the welding requirements, pipe diameter, offset amount and weld gap are strictly controlled.

4. For welding, both internal and external welding use American Lincoln welding machines for single-wire or double-wire submerged arc welding to obtain stable welding quality. All completed welds are inspected by an online continuous ultrasonic automatic flaw detector to ensure complete non-destructive testing coverage of spiral welds.

5. Cutting, the spiral seam submerged arc welded steel pipe is cut into single pieces by air plasma cutting machine, usually 12 meters, and can be cut according to the customer's requirements.

6. Inspection: After the spiral submerged arc welded steel pipe is cut into individual steel pipes, each batch of steel pipes must undergo a strict first inspection system to check the mechanical properties, chemical composition, fusion status of the weld, the surface quality of the steel pipe, and non-destructive testing. , only after ensuring that the pipe making process is qualified can it be officially put into production.

Ultrasonic testing
There are continuous sonic flaw detection marks on the weld. After manual ultrasonic and X-ray re-examination, if there are indeed defects, they will be repaired and then subject to non-destructive inspection again until it is confirmed that the defects have been eliminated.

X-ray detection
The butt welds of the strip and the pipes where the T-shaped joints intersect with the spiral welds are all inspected by X-ray television or film.

Water pressure detection
Each steel pipe has been tested by hydrostatic pressure, and the pressure is radially sealed. The test pressure and time are strictly controlled by the steel pipe hydraulic pressure microcomputer detection device. The test parameters are automatically printed and recorded. The pipe end is machined to ensure the verticality, bevel angle and bluntness of the end face. The edge is accurately controlled.