ERW Steel Pipe

ERW Steel Pipe (Electric Resistance Welded Pipe) is a longitudinal welded steel pipe manufactured by cold-forming continuous hot-rolled steel coils into cylindrical tubes, then fusing strip edges via high-frequency electric resistance welding without extra welding filler metal.

After welding, internal & external weld burrs are fully removed, followed by online stress-relief heat treatment to homogenize weld metal performance, making the weld mechanical properties nearly identical to base steel. It features ultra-precise dimensional tolerance, consistent wall thickness and smooth inner surface, perfectly matching cleanroom HVAC ventilation, chilled water, fire protection pipeline and industrial medium-low pressure fluid transport systems. Compared with seamless steel pipe, ERW pipe delivers equivalent reliability at 20–40% lower cost, supporting mass engineering procurement.

Manufacturing Process Flow

1. Raw material: Hot-rolled carbon steel coil uncoiling, flattening and edge trimming

2. Continuous cold roll forming into round tube blank

3. High-frequency induction resistance welding (HFW ≥70kHz), edges fused by resistance thermal fusion

4. Internal & external weld flash full scarfing to remove burrs

5. Online stress relief heat treatment to eliminate welding residual stress

6. Sizing & straightening for precise outer diameter and roundness control

7. Hydrostatic pressure test + eddy current non-destructive weld inspection

8. Fixed-length cutting, pipe end finishing (plain / bevel / roll groove)

9. Surface anti-corrosion coating or hot-dip galvanizing

10. Final dimension & appearance inspection, packaging

Main Material & International Standards

Base Carbon Steel Grades

• ASTM A53 Gr.A / Gr.B (General fluid, fire fighting, HVAC water pipe)

• ASTM A500 Gr.B / C (Structural support frame)

• API 5L Gr.B, X42–X70 (Oil & gas gathering pipelines)

• EN10217 P235GH / P265GH (High-temperature HVAC boiler pipelines)

• GB/T 3091 Q235B, Q355B (Domestic industrial engineering standard)

Recognized Global Standards

ASTM A53, ASTM A500, API 5L, EN 10217, EN 10219, ISO 3183, JIS G3444

Complete Size Range Specifications

1. Outer Diameter (OD): Φ21.3mm (1/2”) ~ Φ660mm (26”)

2. Wall Thickness: 1.0mm – 22mm, standard Schedule 10 / 40 / 80 for fluid pipelines

3. Standard Length: 5.8m / 6m / 11.8m / 12m; customized 0.5–22m ultra-long lengths available

4. Pipe End Processing: Plain square cut, 30° bevel welding end, roll groove for quick coupling connection

Surface Anti-Corrosion Treatment Options

1. Black Varnish Coated (Black ERW Pipe): Economical indoor HVAC, temporary construction pipelines

2. Hot-Dip Galvanized HDG ERW Pipe: Zinc coating ≥85μm, anti-rust for humid cleanroom, fire water, outdoor pipelines

3. FBE / 3PE Epoxy Coating: Heavy anti-corrosion for underground buried fluid transmission

4. Bare Uncoated: For post-site painting insulation construction (cleanroom HVAC air main pipe)