Straight seam ERW welded steel pipe manufactured by Fengdie, straight longitudinal weld seam

High Precision Straight Seam Welded Pipes (ERW) - IATF16949 Certified

Straight seam welded pipe — also called longitudinal welded pipe, ERW pipe is manufactured by rolling steel strip into shape and welding it longitudinally under high-frequency resistance welding — producing excellent dimensional accuracy at 15-35% lower cost than seamless tube. As an IATF16949 certified factory, FENGDIE supplies straight seam welded pipe from OD 15-90mm to API 5L, ASTM A53 and EN standards, for automotive, hydraulic, and industrial machinery applications.

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Straight Seam Welded Pipe Specifications & Size Chart (ERW & LSAW)

Fengdie produces straight seam welded pipe across the full commercial range — from a 1/2" fence tube to a 60" heavy-wall piling pipe. ERW/HFW covers everything up to 24"; LSAW covers 16"–60" and all thick-wall, high-pressure requirements. The table below lists the core parameters

	Item	Parameters
	Technique	Direct Welding
	Material(Customizable)	Carbon Steel, Stainless Steel
	OD	15-90mm
	Thickness	1-5mm
	Application	Automotive Parts, Precision Mechanical Parts
	Certification	CE、CNAS、CMA
	Custom CNC Manufacturing

Straight Seam Welded Pipe Weight Chart (kg/m)

Nominal Size	OD (mm)	SCH40 WT	SCH80 WT
1/2" (DN15)	21.3	2.77	3.73
2" (DN50)	60.3	3.91	5.54
4" (DN100)	114.3	6.02	8.56
8" (DN200)	219.1	8.18	12.70
12" (DN300)	323.9	10.31	17.48
24" (DN600)	610.0	17.48	30.96

Steel Grade Equivalents — API 5L / GB / EN

API 5L / ASTM	GB/T (China)	EN (Europe)	Yield (MPa)
Gr.B / A53 Gr.B	Q235B	S235JR	≥ 235
X52	Q355B (Q345B)	S355JR	≥ 355
X60	Q420	S420	≥ 415
X65/X70	Q460/Q490	S460	≥ 450–485

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Key Features of Fengdie ERW & LSAW Straight Seam Welded Pipe

Two processes, one factory

Fengdie runs both ERW and LSAW lines in the same mill, so one supplier covers your entire 1/2"–60" pipe list with one certificate package and one shipment.

100% weld inspection.

Every ERW pipe is online eddy-current tested; every LSAW pipe gets ultrasonic and X-ray inspection on the seam; and every pipe, without exception, passes a hydrostatic test before it ships.

Uniform wall thickness

Formed from rolled coil and plate, our pipe holds tighter, more consistent wall thickness than hot-rolled seamless pipe — important for even coating and predictable pressure rating.

Full-grade capability. From Q235B and Gr

B structural pipe to X70 PSL2 line pipe, we cover the grades global projects actually specify, with mill certificates traceable to every heat.

Coating in-house

Hot-dip galvanizing, 3PE, FBE and internal lining are done in our own facility, so coated pipe ships on the same lead time as bare pipe — no outside coating-yard delays.

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Fengdie straight seam welded pipe product catalogue cover

High Quality Precision Straight Seam Welded Pipe Flowchart

A pipe is only as good as its weakest weld. Every Fengdie straight seam welded pipe follows a fully traceable route from raw coil/plate to loading port, and every step below is open to your auditor or our free live-video inspection.

High-frequency ERW welding forming straight seam steel pipe from steel strip

Raw Material Selection & Preparation
High-grade hot-rolled or cold-rolled steel coils (low-carbon, alloy, or precision grades) are strictly inspected for chemistry, surface quality, and defects. Coils are uncoiled, leveled, and straightened to ensure flat, consistent strip feeding—critical for dimensional accuracy in precision ERW pipes.

Slitting & Edge Preparation
Coils are precisely slitted to exact widths; edges are milled or trimmed for perfect parallelism and cleanliness. This step minimizes weld gaps and ensures high-quality seam formation in high-precision straight seam welded tubes.

Precision Forming
The flat strip passes through multiple high-accuracy roll stands, gradually forming into an open "C" then closed "O" tube blank with a straight longitudinal seam. Advanced forming controls deliver superior roundness, wall uniformity, and minimal residual stress—hallmarks of precision welded pipes.

High-Frequency (HF) ERW Welding
The core process: high-frequency induction or contact welding heats edges via skin and proximity effects to molten state (>1000°C), then squeeze rolls forge a strong, narrow, filler-free weld. Tight parameter control creates a small heat-affected zone (HAZ), high weld strength matching base metal, and defect-free seams for premium quality.

Weld Flash Removal & Online NDT
Internal and external weld beads (flash) are immediately scarfed or milled for smooth ID/OD surfaces—essential for precision applications. Real-time ultrasonic or eddy current testing detects any weld imperfections, ensuring zero-defect high-quality straight seam pipes.

Heat Treatment, Cooling & Sizing
Post-weld normalizing or stress-relief annealing refines weld/HAZ microstructure, relieves stress, and enhances toughness. Controlled cooling followed by precision sizing rolls achieves tight tolerances (±0.1–0.3 mm on diameter, ovality, and straightness), delivering automotive-grade precision ERW tubes.

Final Cutting, Finishing & 100% Inspection
Flying cut-off to length, end chamfering/beveling/machining, anti-rust coating, and bundling. Comprehensive testing includes dimensional checks, hydrostatic pressure, full-body NDT, mechanical properties, and visual inspection—meeting standards like ASTM A513, EN 10305, GB/T 13793, and IATF 16949 for shock absorbers, hydraulic cylinders, and structural uses.

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Applications of Straight Seam Welded Pipe

Straight seam welded pipe (also known as longitudinally welded steel pipe or LSAW/ERW straight seam pipe) is a type of welded steel pipe where the weld runs parallel to the pipe's length. It is produced by forming steel plates or strips into a cylindrical shape and welding the seam longitudinally, often via processes like Electric Resistance Welding (ERW) or Submerged Arc Welding (LSAW).

Fluid Transportation
Widely used for conveying low- to medium-pressure fluids such as water, gas, air, oil, steam, and LPG, especially in water supply, drainage, urban water systems, and sewage pipelines.

Oil & Gas Pipelines
Commonly applied in onshore long-distance transportation of crude oil, refined oil, natural gas, and mineral slurry, suitable for medium- to high-pressure scenarios.

Construction & Structural Engineering
Used as structural members in buildings, bridges, pile foundations, steel frameworks, columns, beams, scaffolding, and heavy steel structures.

Agricultural & Municipal Projects
Employed in farmland irrigation, urban drainage and sewage systems, fire protection pipelines, and various municipal infrastructure developments.

Other Industrial Applications
Includes power engineering (e.g., conduit sleeves, boiler heat exchangers), petrochemical and chemical process piping, offshore supporting structures, and other low- to medium-pressure industrial pipelines.

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About Fengdie — China Straight Seam Welded Pipe Manufacturer

Changzhou Fengdie Metal Technology Co., Ltd.is leading manufacturer and supplier of high-precision ERW and LSAW steel pipe in China, we specialize in cold rolled precision Equipped with cold rolling mills, veneer cutting machines, circular saws, pipe cutting machines, chamfering machines, ultrasonic cleaning machines, CNC lathes, etc., the company has extensive experience in pipe manufacturing and processing. We supply various precision tubes, cold-drawn tubes, honed tubes, welded tubes, and other long tubes, and can perform CNC precision machining. Our products are widely used in automobiles, motorcycles, construction machinery, hydraulic cylinders, pneumatic cylinders, metal structural parts, precision equipment, and other fields, with stable and reliable quality.

Our products feature exceptional dimensional accuracy (±0.025–0.08mm OD tolerance), superior surface finish (Ra ≤0.2–0.8μm), enhanced mechanical properties, and reliable performance under high pressure and fatigue conditions. We offer a wide range of specifications (OD 4–325mm, wall thickness 0.5–30mm) in steel grades like E235, E355, ST52, CK45, and more, with customizable options including honing, skiving, galvanizing, phosphating, and heat treatments (+C, +SR, +QT).

Serving global markets—including Japan, Europe, and beyond—we supply Tier 1/Tier 2 customers in hydraulic systems, automotive components (shock absorbers, steering), precision machinery, construction equipment, and industrial applications. Committed to quality, we hold ISO 9001/IATF 16949 certifications, provide EN10204 3.1/3.2 material certificates, and ensure stable delivery with flexible MOQs for both trial and bulk orders.

Hydraulic Cylinder Pipe

Welded Pipe

Precision Seamless Steel Pipes

As a direct source manufacturer, we deliver factory-direct, high-quality tubular solutions designed for rigorous industrial applications. Beyond our flagship cold-rolled precision seamless steel pipes, our core manufacturing capabilities include:

- Hydraulic Cylinder Pipe: We manufacture premium hydraulic pipes, specializing in internally honed, skived, and roller-burnished hydraulic cylinder tubes designed for optimal fluid power performance.
- Welded Pipe: A cornerstone of our production is the Straight Seam Welded Pipe (including ERW). Produced via high-frequency resistance or submerged arc welding, these pipes feature a parallel seam. They offer excellent dimensional accuracy, high production efficiency, and cost-effectiveness, making them the preferred choice for medium-to-low pressure applications.
- Precision Seamless Steel Pipes: Serving as our flagship product, our cold-rolled precision seamless pipes are engineered for applications requiring exact tolerances, smooth surface finishes, and superior structural integrity.

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Certifications & Standards for Our Straight Seam Welded Pipe

Fengdie straight seam welded pipe is produced under an ISO 9001 quality management system and, for line pipe, carries the API 5L monogram.

Every shipment carries a Mill Test Certificate to EN 10204 3.1 as standard, listing the actual heat chemistry and mechanical results — each pipe is stencil-marked with its heat number so any length in your project traces straight back to our factory's records. EN 10204 3.2, witnessed by Lloyd's Register, Bureau Veritas or SGS, is available on request.

Fengdie IATF 16949 quality management certificate for ERW straight seam steel pipe manufacturing

Get Straight Seam Welded Pipe — Step by Step

1.We Respond to Your Inquiry Within 12 Hours

Whether you're asking about straight seam welded pipe specifications, wall thickness and tolerances, steel grades (Q235B, Q355B, API 5L Gr.B–X70), standards (API 5L, ASTM A53/A252, EN 10219, GB/T 3091), pricing, MOQ, delivery time, custom ends, coatings, samples, or certificates — a pipe engineer at our factory replies within 12 hours. You're talking to the manufacturer directly, not a trading company relaying your message to someone else.

2.We Confirm Your Custom Pipe Specification

As a straight seam welded pipe manufacturer, we deliver fast turnaround on custom requirements for ERW and LSAW pipe. From cut-to-length and special bevels to threaded, grooved or plain ends, custom coatings, and piling accessories such as shoe plates and splice rings — our factory engineering team confirms your exact drawing and turns around a free sample in as little as 7–15 days, then moves straight into full-scale production at our mill.

3.We Run Efficient ERW & LSAW Manufacturing

As the manufacturer and mill operator, we run high-frequency ERW/HFW lines and a JCOE LSAW line side by side in our own factory, backed by 100% weld inspection — online eddy current testing, ultrasonic and X-ray inspection on every seam, plus a hydrostatic test on every pipe — for consistent quality at high volume, direct from the producer.

4.We Provide Export-Ready Pipe Packaging

As your straight seam welded pipe supplier and manufacturer, we handle export packing in-house at our own factory. Options include steel strapping with bevel protectors and end caps, waterproof woven wrap for galvanized and coated pipe, wooden dunnage or steel cradles for large-diameter LSAW pipe, and fumigation-free packing (IPPC/ISPM 15 compliant) — tailored for damage-free shipping, straight from mill to port.

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Straight Seam Welded Pipe Manufacturer Packing, Shipping & Delivery

Bundle Packaging — The most common method. Tubes are grouped by grade, size, heat number, and batch (typically 50–150 pieces per bundle, depending on diameter and weight), securely fastened with steel straps, steel wire, or plastic banding to prevent movement and impact. Bundle weight is usually controlled at 50–80 kg for smaller precision tubes, up to 2–3 tons (or more with buyer approval). Uniform labels include steel grade, size, heat number, batch, etc.

Surface Protection — High surface finish tubes are coated with anti-rust oil (rust preventive oil), then wrapped in moisture-proof paper, plastic film, VCI (volatile corrosion inhibitor) paper/film, woven bags, or stretch/shrink film to prevent rust, scratches, and moisture ingress. Common keywords: oiled and wrapped precision tubes, rust prevention packaging.

Wooden Box / Crate Packaging — Preferred for high-value, small-diameter, thin-wall cold-drawn precision tubes (wall thickness ≤1.5 mm), polished tubes, or export shipments. Tubes are packed in sturdy plywood crates, wooden boxes, iron cases, or moisture-lined containers, with end caps or seals, and internal cushioning (e.g., foam or separators) for impact protection. Keywords: export worthy wooden crate, sea freight precision tube packaging, container loading for seamless tubes.
Additional Protective Measures — For long-haul or sea transport, extra features like plywood separators, foam cushioning, and secure lashing ensure no damage during transit.

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What are offering about Straight Seam Welded Pipe？

Cost-Effective & High Production Efficiency
We provide straight seam welded pipes (ERW/LSAW) at 15–35% lower cost than seamless pipes, with fast production lead times (typically 20–45 days), making them ideal for large-volume or budget-sensitive projects without sacrificing reliability.

Excellent Dimensional Accuracy & Straight Weld Quality
Featuring a single longitudinal straight seam, our pipes deliver superior roundness, wall thickness uniformity, and straightness. The short weld line reduces defect risks and enables easier 100% NDT inspection (UT/RT/X-ray), ensuring higher quality consistency compared to spiral seam pipes.

Reliable Strength for Medium/Low-Pressure Applications
Manufactured to standards like API 5L (Gr.B–X70), ASTM A53/A252/A500, EN/GB, our pipes offer strong pressure resistance (suitable for ≤10–25 MPa) and good tensile performance—comparable to seamless in many non-extreme uses—while being far more economical.

Wide Size Range & Customization Flexibility
We supply diameters from 1/2" to 60" (DN15–DN1500), wall thicknesses SCH10–XXS, and lengths up to 18m (fixed or random). Various surface finishes (bare, oiled, 3PE/FBE coated, galvanized) and flexible MOQ make them adaptable to diverse project needs.

Broad Application Coverage
Perfect for oil & gas gathering/transmission lines, water supply & sewage systems, piling/foundation (structural), building columns/scaffolding, industrial fluid transport (air/steam/chemicals), and well casing—meeting demands in petrochemical, urban construction, power, agriculture, and heavy infrastructure.

Full Quality Assurance & Global Supply Reliability
Using traceable raw materials from major mills, advanced welding lines, mandatory hydrostatic/NDT testing, and third-party inspection support (SGS/BV/TÜV), we ensure MTC compliance and stable export to 60+ countries with competitive factory-direct pricing and fast delivery.

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FAQ of Straight Seam Welded Pipe

Q What are the main advantages of straight seam welded pipes?
A
- Cost-Effective: Straight seam welded pipes are typically more affordable to produce compared to seamless pipes.
- Good Strength: The straight seam weld offers strong integrity and resistance to pressure.
- Flexibility: These pipes can be used in a wide range of applications.
- Standard Sizes: They are available in various sizes and specifications.
Q What are the main advantages of welded stainless steel pipe?
A
- Lower cost — More economical to produce than seamless, especially in larger diameters and thinner walls.
- Wide availability — Easier to produce in long lengths, large diameters, and various wall thicknesses.
- Better tolerances — Often tighter dimensional control and concentricity.
- Suitable for many applications — Ideal for low- to medium-pressure uses, structural, decorative, and general corrosive environments.
Q How is a straight seam welded pipe produced?
A
- Plate Rolling: A steel plate is rolled into a cylindrical shape.
- Edge Preparation: The edges of the rolled plate are prepared to ensure a strong weld.
- Welding: The prepared edges are welded together along a straight seam.
- Cooling & Finishing: The welded pipe is cooled and further processed (cut to length, cleaned, coated, etc.) as per customer requirements.
Q What is the difference between straight seam welded pipes and spiral welded pipes?
A
- Straight seam welded pipes have a weld seam along the length of the pipe, while
- Spiral welded pipes are formed by continuously wrapping a steel strip in a spiral pattern, which results in a helical seam.