High-frequency straight seam welded steel pipes can be divided into straight-seam high-frequency electric resistance welded steel pipes and straight-seam high-frequency induction welded steel pipes according to different high-frequency welding processes. The forming process generally adopts roll bending cold forming method.
High-frequency straight seam welded steel pipes are generally produced with smaller calibers, generally below 660mm or 26 inches in outer diameter. Its characteristics are: fast welding speed, for example, for steel pipes with an outer diameter of less than 1 inch, the maximum welding speed can reach 200 m/min.
For steel pipes with an outer diameter of 25 inches, the welding speed can also reach more than 20 m/min. The welding is a crimping method instead of fusion welding. Compared with fusion welding, the welding heat-affected zone is relatively small and has little effect on the structure of the base metal. The strength and toughness of the weld after welding are different from those of the parent body. According to the needs of the material, the internal and external welding burrs can be cleaned or not cleaned. Welding does not need to clean up the workpiece, and can weld thin-walled pipes and weldable metal pipes.
High frequency straight seam welded steel pipe process: slitting-uncoiling-strip flattening-head and tail shear-strip butt welding-looper storage-forming-welding-removal of burrs-sizing-flaw detection-flying cutting-initial inspection -Steel pipe straightening-pipe section processing-hydraulic test-flaw detection-printing and coating-finished product.
High-frequency straight seam welded steel pipes are mainly used in water supply engineering, petrochemical industry, chemical industry, electric power industry, agricultural irrigation, and urban construction.
Used for liquid transportation: water supply and drainage. Used for gas transportation: coal gas, steam, liquefied petroleum gas. For structural purposes: as piling pipes and bridges; pipes for docks, roads, and building structures.
For conveying gas, water and oil either in the oil or natural gas industries.
| OD | 21.3mm -660mm |
| W.T | 1mm-20mm |
| LENGTH | 0.5mtr-22mtr |
| Surface | Fusion bond Epoxy coating, Coal Tar Epoxy, 3PE, Vanish Coating , Bitumen Coating, Black Oil coating as per customer’s requirement |
| Standard | API5L, ASTM A53 GR.B, ASTM A178, ASTM A500/501, ASTM A691, ASTM A252, ASTM A672, EN 10217; API SPEC 5L ISO 3183 GB/T 9711.1 GB/T 9711.2 GB/T 9711.3 |
| Ends | Square Ends (straight cut, saw cut) Beveled Ends |
|
Standard |
Out Diameter |
Tolerance of Pipe |
End Tolerance of Pipe Body |
|
API 5L |
219.1～273.1 |
+1.6mm-0.4mm |
±0.75% |
|
274.0～320 |
+2.4mm-0.8mm |
±0.75% |
|
|
323.8～457 |
+2.4mm, -0.8mm |
±0.75% |
|
|
508 |
+2.4mm, -0.8mm |
±0.75% |
|
|
559～610 |
+2.4mm, -0.8mm |
±0.75% |
|
Standard |
Grade |
Out Diameter |
Wall Thickness |
|
API 5L |
A |
219.1～457 |
+15%, -12.5% |
|
B |
508～610 |
+17.5%, -12.5% |
|
|
X42-X80 |
508～610 |
+19.5%, -8% |