Spiral welded steel pipe is also a type of welded pipe equipment. Its strength is generally higher than that of straight seam welded steel pipe. It can use narrower billets to produce welded steel pipes with larger diameters. It can also use billets of the same width to produce welded steel pipes with different diameters. Steel Pipe. However, compared with straight seam steel pipes of the same length, the weld length is increased by 30~100%, and the production speed is lower. Therefore, smaller-diameter welded steel pipes mostly use straight seam welding, while large diameter welded pipes mostly use spiral welding.

Spiral steel pipe production process: It is a spiral seam steel pipe welded by automatic double-wire double-sided submerged arc welding process using strip steel coil plate as raw material, constant temperature extrusion molding.
1. The raw materials are steel strip coil, welding wire, and flux. They must undergo strict physical and chemical inspections before being put into use.
2. The head and tail of the steel strip are butt-jointed using single-wire or double-wire submerged arc welding. After being rolled into a steel pipe, automatic submerged arc welding is used for repair welding.
3. Before forming, the strip steel is leveled, trimmed, planed, surface cleaned, transported, and pre-bent.
4. Electric contact pressure gauges are used to control the pressure of the cylinders on both sides of the conveyor, ensuring smooth conveying of the strip.
5. Adopt external control or internal control roller forming.
6. The weld gap control device is used to ensure that the weld gap meets the welding requirements. The pipe diameter, offset amount, and weld gap are strictly controlled.
7. Both internal and external welding use electric welding machines for single-wire or double-wire submerged arc welding to obtain stable welding specifications.
8. All completed welds are inspected by an online continuous ultrasonic automatic flaw detector, ensuring 100% non-destructive testing coverage of spiral welds. If there is a defect, it will automatically alarm and spray mark, so that production workers can adjust the process parameters at any time to eliminate defects in time.
9. Use an air plasma cutting machine to cut the steel pipe into individual pieces.
10. After cutting into individual steel pipes, the first three steel pipes in each batch must undergo a strict first inspection system to check the mechanical properties, chemical composition, fusion status of the welds, the surface quality of the steel pipes, and non-destructive testing to ensure that the pipe making process is qualified. Only then can it be officially put into production.
11. The areas with continuous sonic flaw detection marks on the welds will undergo manual ultrasonic and X-ray re-examination. If there are indeed defects, they will be repaired and then undergo non-destructive inspection again until it is confirmed that the defects have been eliminated.
12. The butt welds of the strip steel and the pipes where the T-shaped joints intersect with the spiral welds are all inspected by X-ray television or film.
13. Each steel pipe has undergone a hydrostatic pressure test, and the pressure is radially sealed. The test pressure and time are strictly controlled by the steel pipe water pressure microcomputer detection device. Test parameters are automatically printed and recorded.
14. The pipe end is machined to accurately control the end face verticality, bevel angle, and blunt edge.


Anti-corrosion spiral welded steel pipe technology
Since the individual mass of spiral welded steel pipes is relatively large, they must be stacked outdoors. However, they will inevitably be exposed to the sun and rain, so the problem of rust has always plagued the storage time and conditions of spiral welded steel pipes. Therefore, we must provide a comprehensive answer to the anti-rust knowledge of spiral welded steel pipes. Mainly use tools such as wire brushes to polish the steel surface. Cleaning and preheating spiral welded steel pipes can remove loose or lifted oxide scales, rust, welding slag, etc. The rust removal of hand tools can reach the Sa2 level, and the rust removal of power tools can reach the Sa3 level. If the iron oxide scale is firmly attached to the surface of the steel, the rust removal effect of the tool will not be ideal and the anchor pattern depth required for anti-corrosion construction will not be achieved. Pickling uses solvents and emulsions to clean the surface of welded steel pipes (welded steel pipes) for low-pressure fluid transportation to remove oil, grease, dust, lubricants, and similar organic matter, but it cannot remove rust, oxide scale, flux, etc. on the steel surface. , so it is only used as an auxiliary means in anti-corrosion production. Generally, chemical and electrolytic methods are used for pickling treatment. Only chemical pickling is used for pipeline anti-corrosion, which can remove scale, rust, and old coatings. Sometimes it can be used as a reprocessing after sandblasting and rust removal. Although chemical cleaning can achieve a certain degree of cleanliness and roughness on the surface, its anchor lines are shallow and can easily cause pollution to the stacking environment of spiral welded steel pipes. Reasonable use of means to clean rusty pipe fittings ensures that the pipe fittings can serve production for a long time and create more production benefits.