ERW Pipe

ERW pipe (Electric Resistance Welded pipe) is a welded steel pipe manufactured from flat steel strip or coil, which is formed into a cylindrical shape and welded longitudinally by high-frequency electric resistance welding. The weld is created by heating the strip edges with electric current and forging them together under pressure, without the use of filler metal.

In modern production, ERW pipe typically refers to high-frequency ERW pipe (HF-ERW or HFI welded pipe), which offers stable weld quality, consistent dimensions, and high manufacturing efficiency for standard pipe sizes.

ERW Pipe vs Seamless Pipe – Basic Understanding

Compared with seamless pipe in the same diameter range, ERW pipe is produced from steel coil and benefits from: More uniform wall thickness control, Tighter outside diameter tolerances, Higher production efficiency, Lower material and manufacturing cost. For many low to medium pressure applications, ERW pipe fully meets design and code requirements while offering a more economical solution than seamless pipe.

Service / Condition	Preferred Pipe Type	Engineering & Cost Consideration
Onshore pipelines within moderate pressure and temperature (API 5L gathering and transmission lines)	ERW Pipe	ERW pipe offers stable wall thickness, consistent OD and reliable weld performance, while providing a clear cost advantage over seamless pipe for standard onshore applications.
Water, gas and low-pressure fluid service (utilities, fire protection, cooling water)	ERW Pipe	ERW pipe fully meets code requirements for low and medium pressure duties, avoiding the unnecessary cost of seamless pipe in non-critical services.
Structural and mechanical applications (supports, frames, racks)	ERW Structural Pipe	ERW pipe provides excellent dimensional control and straightness, making it more economical than seamless pipe for static load-bearing structures.
Standard pipe sizes up to approx. 24″ OD	ERW Pipe	High-frequency ERW pipe production from coil enables high output, shorter lead time and lower unit cost for bulk project sizes.
High-temperature or very high-pressure services (boiler tubes, critical steam lines)	Seamless Pipe	Seamless pipe is better suited for extreme pressure and temperature conditions where additional safety margin is required by design codes.
Severe sour service or fatigue-critical conditions (H2S environments, cyclic loading)	Seamless Pipe	Project specifications typically require seamless pipe to reduce risk under sour service or high cyclic stress conditions.
Practical engineering selection rule	Prefer ERW Pipe where allowed	Use ERW pipe wherever codes and client specifications permit, reserving seamless pipe only for genuinely critical services to optimize total project cost.

 

ERW Pipe Supplied by Octal Steel

Octal Steel supplies ERW pipe and API 5L ERW line pipe from qualified and audited mills, covering international standards for fluid service, line pipe, and structural use.

Typical supply scope of ERW pipe:

Outside Diameter: approx. 1/2″–24″ (21.3–610 mm)

Wall Thickness: approx. 1.8–16 mm, depending on size and standard

Length: 6–12 m (SRL / DRL) or fixed lengths on request

Pipe Type: High-frequency ERW pipe (HF-ERW / HFI welded)

Ends: Plain end, bevelled end, or threaded & coupled

Surface: Black, varnished, galvanized, or coated (FBE / 3LPE / paint)

Standard	Product Type	Typical Grades	Typical Application
API 5L	ERW Pipe	Gr.B, X42–X60 (on request)	Onshore ERW pipe for oil, gas and water transportation
ASTM A53	ERW Carbon Steel Pipe	Grade A, Grade B	Water, gas, low-pressure fluid service and mechanical use
ASTM A135	ERW Pipe (Type E)	Grade A, Grade B	Fire mains, sprinkler systems, water and gas distribution
EN 10219	ERW Structural Pipe	S235, S275, S355	Structural ERW pipe for construction frameworks and supports

On request, ERW pipe can be supplied with restricted chemistry, improved weld-ability, and additional impact testing for low-temperature or specific project requirements.

ERW Pipe(High-Frequency)Manufacturing Process

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

Uncoiling & Slitting – Hot rolled or pickled coil is uncoiled and slit to precise strip width, matching the required ERW pipe diameter.

Forming – The strip passes through a series of forming rolls that gradually bend it from flat strip into an open circular section.

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.

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.

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.

Non-Destructive Testing (NDT)– Modern ERW steel pipe lines use online ultrasonic or eddy current testing on the weld seam. Finished pipes are hydro-tested, visually inspected and dimension-ally checked.

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 pipe has become the standard solution in many non-critical and medium-duty pipelines.

Standard	ERW Pipe Type	Typical Grades	Typical Applications
API 5L	ERW Pipe	Gr.B, X42, X52, X60	Onshore oil, gas and water transmission pipelines
ASTM A53	ERW Carbon Steel Pipe	Grade A, Grade B	Water, gas and low-pressure fluid service
ASTM A135	Electric Resistance Welded Pipe (Type E)	Grade A, Grade B	Fire mains, sprinkler systems, water and gas distribution
EN 10219	ERW Structural Hollow Section	S235, S275, S355	Structural frames, supports and construction applications

Typical Applications of ERW Carbon Steel Pipe

ERW carbon steel pipe is commonly selected for applications where stable dimensions, reliable weld quality, and cost efficiency are required. Typical uses include:

Water and Gas Distribution
Used in municipal water and gas networks, building service pipelines, and fire protection systems such as sprinkler lines, typically supplied to ASTM A53 or ASTM A135 standards.

Low Pressure Fluid Service
Applied in industrial facilities for cooling water, compressed air, low-pressure oil, and other non-hazardous fluids where consistent pipe geometry and good weldability are important.

Onshore Line Pipe Systems
API 5L ERW line pipe is widely used in gathering lines, utility pipelines, and low to medium pressure transmission systems for oil, gas, and water onshore.

Structural and Mechanical Applications
EN 10219 ERW structural pipe is commonly used in building frames, supports, towers, handrails, and general mechanical structures where dimensional accuracy and repeatable strength are required.

General Engineering and Fabrication
Suitable for fabricated components such as frames, platforms, racks, ladders, and other assemblies where straightness, ease of welding, and consistent sizing simplify fabrication and installation.

Quality Control and Testing for ERW Welded Pipe

To ensure reliable performance in pipeline and structural applications, Octal Steel works closely with qualified mills that implement robust and well-documented quality control systems for high-frequency ERW welded pipe production.

Key quality control and testing measures include:

• • Verification of steel coil chemistry and mechanical properties in accordance with API, ASTM, and EN standards

• Precise strip slitting and controlled forming processes to minimize weld misalignment and dimensional deviation

• High-frequency electric resistance welding (HF-ERW / HFI) with strictly controlled welding parameters to ensure stable weld seam quality

• Online ultrasonic or eddy current testing applied continuously to the ERW welded pipe seam during production

• Hydrostatic testing on each pipe length when required by the applicable standard or project specification

• Comprehensive visual inspection, dimensional measurement, and verification of end preparation before delivery

Full EN 10204 3.1 or 3.2 Mill Test Certificates are provided for ERW welded pipe shipments, documenting chemical composition, tensile properties, impact test results (when specified), and NDT records for each heat and production batch, ensuring complete traceability and compliance.

Why Choose Octal Steel for ERW Steel Pipe

Standards-Based ERW Steel Pipe Supply
Octal supplies ERW steel pipe manufactured in accordance with API 5L, ASTM A53, ASTM A135, EN 10219, and project-specific technical requirements. Each ERW steel pipe shipment is supported by complete EN 10204 3.1 / 3.2 mill test certificates, allowing ERW steel pipe quality and compliance to be verified by owners, EPC contractors, and third-party inspectors.

Cost-Effective ERW Steel Pipe Solutions for Line Pipe Projects
Where design codes and service conditions allow, Octal assists clients in applying ERW steel pipe—including API 5L ERW steel pipe and general ERW carbon steel pipe—as a practical alternative to seamless pipe. This approach enables meaningful cost control on large-volume pipeline projects while maintaining the required safety margins and performance of ERW steel pipe in service.

Complete ERW Steel Pipe Supply Packages
In addition to straight-length ERW steel pipe, Octal can supply matching bends, fittings, flanges, coating systems, and full QA documentation under a single ERW steel pipe supply scope. This integrated approach reduces interface risk, simplifies procurement management, and improves overall project execution efficiency.

Export-Oriented Experience with ERW Steel Pipe Projects
Octal has experience supplying ERW steel pipe for international pipeline and infrastructure projects. Packing, marking, and logistics for ERW steel pipe are arranged to suit long-distance export shipment, with seaworthy packing and documentation prepared for projects in the Middle East, Europe, North America, Africa, and Asia.

Engineering Support for ERW Steel Pipe Selection
Technical support is available for ERW steel pipe selection, including standard comparison, wall thickness confirmation, coating system selection, and practical guidance on ERW steel pipe versus seamless pipe based on actual service conditions and project specifications.

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