High Precision Straight Seam HFW Steel Pipe

HFW is a premium straight-seam electric resistance welding process, using non-contact induction coils (300–500 kHz) to generate eddy currents, heating the strip edges to 1350–1450°C for pressure fusion without filler/flux. The high-speed welding minimizes the heat-affected zone (HAZ), ensuring uniform wall thickness and tight dimensional tolerances.Core workflow: Uncoiling → Leveling → Edge trimming → Continuous roll forming → Induction heating & squeeze welding → Online heat treatment (annealing) → Sizing & straightening → Ultrasonic/eddy current inspection → Cut-to-length & packaging.

Key Precision Features & Specs

Dimensional Accuracy: OD tolerance ±0.1–0.3 mm, wall thickness deviation ≤±3–5% (superior to standard ERW/seamless); roundness ≤0.5% of OD; straightness ≤1 mm/1000 mm.

Material Grades: API 5L (Gr.B/X42/X56/X70 PSL1/PSL2), ASTM A53, EN 10217, GB/T 9711; carbon/micro-alloy steel strips (Q235, Q345, 20#).

Size Range: OD 76mm–660.4 mm; wall thickness 2.5 mm–25 mm (thick-wall HFW up to 15 mm for high pressure); length 6 m/12 m or custom 3–24 m.

Weld Quality: 100% online UT inspection, X-ray spot check, HIC/SSC tests for sour service; weld strength often ≥ base metal.