Longitudinal Welded Steel Pipes

Main Executive Standards

• ASTM Standards:

  o ASTM A53/A53M: Seamless and welded steel pipes for pressure piping and general service, available in wall thickness grades such as Sch40 and Sch80, with material grades including Grade A and Grade B carbon steel.

  o ASTM A333: Seamless and welded steel pipes for low-temperature service, suitable for environments from -45℃ to -196℃, classified into Grades 1-9 based on toughness requirements.

• API Standards:

  o API 5L: Specification for line pipe, used in long-distance oil and gas transmission pipelines, divided into PSL1 (standard grade) and PSL2 (high grade), with material grades covering high-strength steel such as X42-X100.

• Other Standards: ASME B36.10M (Welded and Seamless Wrought Steel Pipe), ASTM A252 (Welded Steel Piles for Piling Purposes), etc., can be implemented according to customer requirements.

 Core Technical Parameters

• Material: Low carbon steel (e.g., A53-B, API 5L B), low alloy steel (e.g., X42-X70), stainless steel (e.g., 304, 316, custom-specified).

•Specification Range:

  o Outer Diameter (OD): 1/2 inch (12.7mm) – 24 inches (609.6mm), larger diameters available on customization;

  o Wall Thickness (WT): Sch10-Sch160, XXS, or customized per customer requirements;

  o Length: Fixed length (e.g., 6m, 12m) or random length, maximum length up to 18m.

• Welding Process: Electric Resistance Welding (ERW) and Submerged Arc Welding (SAW). ERW is suitable for small and medium diameters, while SAW is applicable for large-diameter and thick-walled pipes.

Product Features

1. High-Precision Dimensional Control: Adopting CNC forming equipment, with outer diameter tolerance of ±0.5%, wall thickness tolerance of ±10% (complying with ASTM standards), and straightness ≤1.5mm/m, ensuring pipeline connection tightness and structural stability.

2. Excellent Mechanical Properties: Grain structure optimized through online heat treatment (normalization, tempering), with tensile strength ≥355MPa, yield strength ≥245MPa, elongation ≥20%, and low-temperature impact toughness (-20℃) ≥27J (for low-temperature steel).

3. Corrosion and Pressure Resistance:

   Optional surface treatments include galvanizing (hot-dip galvanizing, electro-galvanizing) and painting (epoxy coal tar pitch, 3PE anti-corrosion coating), enhancing resistance to acid, alkali, and soil corrosion;

   Weld seams undergo 100% X-ray inspection and hydrostatic test (test pressure ≥2.45MPa, holding pressure for 30 seconds without leakage) to ensure safety under high-pressure working conditions.

Application Fields

1. Energy Industry: Oil and gas transmission trunk and branch pipelines (API 5L PSL2), shale gas fracturing pipes, power station steam pipelines (ASTM A106 Gr.B).

2. Municipal and Construction: Urban water supply/drainage networks, bridge steel structure supports, welded steel piles for piling (ASTM A252), subway tunnel support.

3. Chemical and Industrial: Acid-alkali solution transportation, refinery process pipelines, boiler heat exchanger tubes, structural tubes for mechanical processing.

4. Marine Engineering: Seawater desalination pipelines, offshore platform structural tubes (additional marine-grade anti-corrosion treatment required).

Quality Control

Full-Process Quality Inspection:

- Raw Materials: Spectral analysis, tensile test, impact test to ensure material compliance;

- Production Process: Weld ultrasonic testing (UT), eddy current testing (ET), metallographic analysis;

- Finished Products: Hydrostatic test, dimensional re-inspection, surface quality inspection (free of cracks, depressions, and laminations).

Packaging and Services

• Packaging: Plastic end caps installed at both ends of pipes, bundled or palletized packaging. Export products undergo rust-proof treatment per marine standards (VCI anti-rust bags + fumigated wooden cases).

• Customization Services: Supports customization of non-standard sizes, special materials (e.g., low-temperature steel, wear-resistant steel), and anti-corrosion coatings (3PE, FBE). Provides technical consultation and installation guidance.

Note: Specific parameters, materials, and applications can be further optimized according to customer requirements. Please provide project drawings or standard specifications to obtain targeted solutions.