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Welded Stainless Steel Pipe

Straight Seam Welded Pipe

Straight seam welded pipe is a steel pipe made by rolling steel strips or plates into shape and then welding them longitudinally in a straight line using methods such as high-frequency resistance welding (ERW) or submerged arc welding. Its weld seam is parallel to the axis of the steel pipe. The production process is simple, efficient, and low-cost, and it produces pipes with good dimensional accuracy and excellent surface quality. It is widely used in building steel structures, bridge pile foundations, scaffolding, and water/gas/heating pipelines.

Parameters of Straight Seam Welded Pipe

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  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

Characteristics of FengDie's Straight Seam Welded Pipe

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Simple and efficient production process: Formed by bending steel strips or plates and welding along a straight longitudinal seam, leading to high production efficiency, lower costs, and suitability for mass production compared to spiral or seamless pipes.

High geometric accuracy and dimensional precision: Especially in FengDie's precision-oriented manufacturing, with good control over diameter, wall thickness, roundness, and straightness. Pipes often undergo processes like chamfering, expanding, necking, or additional machining.

Short weld seam: The weld length equals the pipe length, reducing defect probability compared to spiral pipes (where weld length is 30-100% longer). This results in fewer welding defects and better overall weld quality.

Welded Stainless Steel Pipe
Excellent surface quality and fewer scratches: Minimal residual stress after stress-relief processes; base metal experiences less damage during production.

Material versatility: Commonly uses carbon steel (e.g., S235JR, ASTM A36, low-carbon or low-alloy steels), with options for galvanizing or other coatings. FengDie also produces stainless steel variants (e.g., 304/316) in smaller/precision sizes.

Strength and performance: Weld strength typically matches or exceeds the base metal. Suitable for moderate-pressure applications; not as high-strength as spiral pipes for very large diameters or high-pressure uses, but reliable for automotive, machinery, and structural needs.

Know Detailed Information
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Cold Rolled Precision Tube

High Quality Precision Straight Seam Welded Pipe Flowchart

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Straight Seam Welded Pipe

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.

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.

Your Expert Precision Steel Tube Supplier

About FENGDIE

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Changzhou Fengdie Metal Technology Co., Ltd.is leading manufacturer and supplier of high-precision steel tubes based 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.

cold rolled precision tubing
cold rolled precision tube
cold rolled precision tubes
cold rolled precision tubing

FENGDIE Certificates And Patents

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Straight Seam Welded Pipe

Get Products Step-by-step

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Respond

1.We Respond to Your Inquiry Within 12 Hours

Whether you are inquiring about cold-rolled precision tube specifications, tolerances (H8-H9 grade), surface finish (Ra≤0.4μm), steel grades (20#, 45#, 20Cr, 42CrMo), standards (DIN 2391, EN 10305, GB/T 3639), pricing, minimum order quantity, delivery time, custom sizes, samples, certifications, or bulk purchasing, our Osaka team will provide you with professional and detailed answers promptly.
 
Customized-Designs

2.We Deliver Customized Products Designs

offers fast custom product design for cold rolled precision tubes, hydraulic tubes, precision steel tubes, and welded steel tubes. From non-standard OD/WT, tighter tolerances (beyond H8/H9), special surface finishes (Ra < 0.2μm), unique steel grades, to custom end machining or enhanced mechanical properties — our engineering team delivers rapid prototyping (samples in as little as 7-15 days) and full-scale production.
 
Manufacturing

3.We Achieve Efficient Products Manufacturing

achieves efficient manufacturing of cold rolled precision tubes, hydraulic tubes, precision steel tubes, and welded steel tubes with advanced cold rolling mills, automated honing & burnishing lines, and high-speed welding systems.
 
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4.We Offer Custom Products Packaging

provides custom packaging for cold rolled precision tubes, hydraulic tubes, precision steel tubes, and welded steel tubes. Options include anti-rust oil, VCI paper, wooden crates, steel pallets, fumigation-free export boxes (IPPC/ISPM 15 compliant), or branded sleeves — tailored for safe, damage-free shipping and storage at competitive cost.
 

Welcome To Visit Our Factory

  • Changzhou Fengdie Metal Technology Co., Ltd.is a leading manufacturer and supplier of cold rolled precision seamless steel tubes, specializing in high-precision, high-performance tubing solutions for hydraulic cylinders, pneumatic systems, automotive components, precision machinery, and industrial applications. With advanced cold rolling production lines (including LG/LD series periodic and multi-roll cold rolling mills), state-of-the-art annealing, straightening, and non-destructive testing equipment, we deliver tubes with tight tolerances (H8-H9 or better), superior surface finish (Ra ≤ 0.4μm), excellent wall thickness uniformity, and outstanding straightness. Using premium hot-rolled seamless blanks as raw material, our products comply with international standards such as IATF16949​​​​​​​、 DIN 2391, EN 10305-1/2, GB/T 3639, and ASTM standards. Committed to quality, innovation, and customer satisfaction, serves clients worldwide with reliable, customized precision tubing that enhances efficiency and durability in demanding environments.
    • Straight Seam Welded Pipe
    • Straight Seam Welded Pipe
    • Straight Seam Welded Pipe
    • Straight Seam Welded Pipe
hydraulic cylinder pipe

Hydraulic Cylinder Pipe

welded pipe

Welded Pipe

Precision seamless steel pipe

Precision Seamless Steel Pipes

In addition to our flagship product, cold-rolled precision seamless steel pipes, our company also specializes in the production of hydraulic pipes (including internally honed/skived and roller-burnished hydraulic cylinder tubes) and various types of welded pipes, with Straight Seam Welded Pipe being one of our core and most widely applied product lines.
Straight Seam Welded Pipe (also known as longitudinal seam welded steel pipe or ERW straight seam pipe) is produced by high-frequency resistance welding or submerged arc welding processes, featuring a straight weld seam running parallel to the pipe axis. It offers excellent dimensional accuracy, high production efficiency, and cost-effectiveness, making it the preferred choice for a wide range of medium-to-low pressure applications.

Shipping and Delivery of Straight Seam Welded Pipe

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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.

What are offering about Straight Seam Welded Pipe？

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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.

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.

Fengdie Metal is a pioneering manufacturer, stockist, and supplier of steel pipe products.
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