HFW Steel Pipe (High-Frequency Welded)

High-frequency butt-welded steel pipe, commonly referred to as HFW pipe in the industry, belongs to the high-performance version within the ERW category.

HFW essentially refers to high-frequency resistance butt-welded steel pipe. It is formed from hot-rolled coil sheets through cold bending into a cylindrical shape. It relies on the skin effect and proximity effect of the high-frequency current to rapidly heat only the two edges of the steel strip to a molten / plasticized state. The compression rolls apply pressure for forging, without using welding wire or flux. Then, the weld beads are scraped off from the inside and outside. Subsequently, it can undergo weld seam heat treatment, UT inspection, and hydrostatic testing

Raw material hot-rolled coil → Unrolling, straightening, edge milling → Continuous roller-type cold bending forming (open pipe tube) → High-frequency induction / contact welding → Removal of internal and external burrs → Heat treatment of welds (common for pipeline tubes) → Diameter control, straightening → Fixed-length cutting → Flat head → Hydraulic test + Ultrasonic inspection → Finished product inspection

1. High dimensional accuracy, uniform wall thickness, good straightness, cold forming, outer diameter tolerance better than seamless tubes;
2. Heat affected zone HAZ is very narrow (1-2mm), heating is extremely fast, the matrix grains are almost unaffected;
3. Fast production speed, high yield rate, cost lower than seamless tubes, suitable for large-scale production;
4. Weld seams can be made to have similar properties to the base material, high-grade HFW can be used for oil and gas pipelines, casing, water supply and drainage, municipal pipelines, pile foundations, steel structures, scaffolding pipes, mineral pulp transportation pipes;
5. Specifications: mainly medium and small diameters, common outer diameters ≤ 610mm (24 inches), wide range of wall thicknesses.

   

• Standards: API 5L (Pipeline Tubes), ASTM A53, EN10217, GB/T 3091, etc.
• Applications: Oil and gas transportation pipelines, oilfield casing, water supply and drainage, municipal pipelines, pile foundations, steel structures, scaffolding pipes, mineral pulp transportation pipes
• HFW vs ERW / LSAW / Seamless Tubes
• HFW = High Performance ERW: Ordinary ERW is low frequency, HFW is high frequency, with weld heat treatment + strict inspection, in the oil and gas pipeline field, HFW generally refers to upgraded high-frequency welded pipes;
• LSAW (Arc Welding Straight Seam): Large diameter (>24 inches), filler wire and flux, wide weld seam, slow production;
• Seamless SMLS: No weld seam, the highest cost, high-pressure harsh conditions; HFW can replace seamless tubes in many medium and high-pressure scenarios.