ERW Pipe

ERW Steel Pipe (High-Frequency Electric Resistance Welded Pipe) Explained

ERW steel pipe is one of the most widely used carbon steel pipe types for low and medium pressure pipelines, water and gas distribution, and structural applications. In modern mills, ERW means high-frequency electric resistance welded pipe (HF-ERW / HFI welded pipe) – using high-frequency current to heat the strip edges and forge them together in a continuous straight seam.

Compared with seamless pipe in the same size range, high-frequency ERW steel pipe offers tight dimensional tolerances, high productivity, and a clear cost advantage, especially for standard sizes up to around 24″.

Octal Steel supplies ERW carbon steel pipe and API 5L ERW line pipe from qualified mills, covering ASTM, EN and API standards for both fluid service and structural use.

ERW Steel Pipe Specifications & Standards

Typical capability range for ERW steel pipe supplied by Octal Steel:

1. Outside diameter: approx. 1/2″–24″ (21.3–610 mm)
2. Wall thickness: approx. 1.8–16 mm depending on size and standard
3. Length: 6–12 m (SRL / DRL) or custom fixed lengths
4. Pipe type: high-frequency ERW pipe (HF-ERW / HFI welded)
5. Ends: plain end, bevelled end, or threaded & coupled on request

Key ERW steel pipe standards and typical uses:

Standard	Product Type	Typical Grades	Typical Use
API 5L	ERW line pipe	Gr.B, X42–X60 (on request)	Onshore ERW line pipe for oil, gas and water
ASTM A53	ERW carbon steel pipe	Grade A, Grade B	Water, gas, low pressure fluid service, mechanical
ASTM A135	Electric resistance welded pipe (Type E)	Grade A, Grade B	Fire mains, sprinkler, water & gas distribution
EN 10219	ERW structural hollow sections	S235, S275, S355	ERW structural pipe for construction and supports

On request, Octal Steel can supply restricted chemistry (lower carbon and sulfur) and additional impact testing to improve weldability and low-temperature performance for both API 5L ERW line pipe and general ERW steel pipe.

High-Frequency ERW Pipe Manufacturing Process

High-frequency ERW steel pipe (HF-ERW / HFI welded pipe) is produced from steel coil in a continuous, highly controlled process:

1. Uncoiling & Slitting
   Hot rolled or pickled coil is uncoiled and slit to precise strip width, matching the required ERW pipe diameter.
2. Forming into Open Tube
   The strip passes through a series of forming rolls that gradually bend it from flat strip into an open circular section.
3. High-Frequency Electric Resistance Welding
   In high-frequency ERW, the strip edges are heated by high-frequency current and immediately forged together under squeeze pressure. The result is a straight-seam weld without filler metal, often called electric resistance welded pipe or HFI welded pipe.
4. Weld Seam Removal & Heat Treatment
   Internal and external weld beads are trimmed as required. For many standards, the weld area is locally normalized / heat treated to refine grain structure and harmonize properties across the weld seam.
5. Sizing & Straightening
   The welded pipe passes through sizing stands that control outside diameter and wall thickness, followed by straightening to achieve tight tolerances and low ovality.
6. Non-Destructive Testing (NDT)
   Modern ERW steel pipe lines use online ultrasonic or eddy current testing on the weld seam. Finished pipes are hydrotested, visually inspected and dimensionally checked.
7. Finishing & Coating
   Pipe is cut to ordered lengths, then ends are bevelled, threaded or left plain. ERW carbon steel pipe can be supplied black, varnished, galvanized, or with external coatings such as 3LPE / FBE / paint for buried or submerged service.

This controlled high-frequency ERW process delivers consistent wall thickness, uniform OD and repeatable weld quality – key reasons why ERW steel pipe has become the standard solution in many non-critical and medium-duty pipelines.

ERW vs Seamless Pipe – How to Choose

Service / Condition	Preferred Pipe Type	Reason (Cost & Performance)
Onshore line pipe within moderate pressure and temperature (API 5L gathering and transmission lines)	ERW steel pipe (API 5L ERW line pipe, Gr.B–X52/X60)	Lower material cost than seamless; coil feedstock and high-frequency welding give stable wall thickness and easier field welding while fully meeting design requirements.
Water, gas and general low pressure fluid service (building services, fire mains, sprinklers, cooling water, utilities)	ERW carbon steel pipe	Meets technical and code requirements with a clear price advantage over seamless pipe for low and medium pressure duties.
Structural and mechanical applications (columns, trusses, racks, general fabrication)	ERW structural pipe (EN 10219 hollow sections)	Provides reliable strength and excellent dimensional control; using seamless in mainly static, low-pressure roles usually adds cost without real benefit.
Standard sizes up to around 24″ OD	ERW steel pipe	High-frequency ERW from coil efficiently covers bulk project sizes; mills can run high volume, reducing unit cost and shortening lead times versus seamless.
High temperature or very high pressure services (boiler tubes, high pressure steam, critical process lines)	Seamless pipe	Better suited for extreme pressure/temperature; often explicitly required by project specifications and design codes.
Severe sour service or extreme cyclic loading (H2S environments, fatigue-critical lines)	Seamless pipe	Project specifications typically demand seamless for additional safety margin under sour or heavy cyclic conditions.
Practical engineering rule	Prefer ERW where allowed	Use ERW steel pipe wherever the design code and client specification allow it, and reserve seamless only for genuinely critical conditions to maximize cost savings on the bulk of tonnage.

 Typical Applications of ERW Carbon Steel Pipe

With its balance of performance and cost, ERW carbon steel pipe is widely used in:

• Water and Gas Distribution
  City water and gas mains, building services, fire protection and sprinkler networks to ASTM A53 or ASTM A135.
• Low Pressure Fluid Service
  Cooling water, compressed air, low pressure oil and non-hazardous media in industrial plants.
• Onshore ERW Line Pipe
  API 5L ERW line pipe serving gathering systems, utility pipelines and low to medium pressure transmission lines.
• Structural and Mechanical Uses
  EN 10219 ERW structural pipe in building frameworks, towers, supports, handrails and mechanical structures.
• General Engineering & Fabrication
  Frames, ladders, platforms, racks and fabricated assemblies where straightness, weldability and repeatable sizes are important.

Quality Control and Testing for ERW Steel Pipe

To ensure reliable service, Octal Steel works with mills that implement robust quality control for high-frequency ERW steel pipe:

• Verified coil chemistry and mechanical properties per API / ASTM / EN standards
• Precise strip slitting and forming to minimize weld misalignment
• High-frequency ERW (HF-ERW / HFI) with controlled welding parameters
• Online ultrasonic / eddy current testing of the weld seam
• Hydrostatic test on each length as required by the standard or project spec
• Visual inspection, dimensional check and end preparation verification

Full EN 10204 3.1 or 3.2 mill test certificates are provided, documenting chemical composition, tensile properties, impact results (if specified) and NDT records for each heat and batch.

Why Choose Octal Steel for ERW Steel Pipe

• Standards-Compliant Manufacturing
  ERW steel pipes produced to API 5L, ASTM A53, ASTM A135, EN 10219 and project-specific requirements, with complete MTC 3.1/3.2.
• Cost-Effective Line Pipe Solutions
  By optimizing the use of API 5L ERW line pipe and ERW carbon steel pipe where codes allow, Octal helps clients reduce overall pipeline cost without compromising safety.
• Project-Ready Packages
  ERW pipe supplied together with bends, fittings, flanges, coatings and documentation – one package, one responsibility.
• Global Supply Capability
  Experience with large export projects, seaworthy packing, and multimodal logistics to the Middle East, Europe, North America, Africa and Asia.
• Engineering Support
  Support on standard selection, wall thickness calculation, coating systems, and “ERW vs seamless” optimization based on your design conditions and specifications.

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