{"id":28286,"date":"2026-04-17T17:58:05","date_gmt":"2026-04-17T09:58:05","guid":{"rendered":"https:\/\/alllandpipes.com\/?p=28286"},"modified":"2026-04-17T18:20:07","modified_gmt":"2026-04-17T10:20:07","slug":"lsaw-vs-ssaw-manufacturing-when-lsaw-pipes-are-irreplaceable","status":"publish","type":"post","link":"https:\/\/alllandpipes.com\/fr\/blogs\/lsaw-vs-ssaw-manufacturing-when-lsaw-pipes-are-irreplaceable.html","title":{"rendered":"Fabrication LSAW vs. SSAW : Quand les tubes LSAW sont irrempla\u00e7ables"},"content":{"rendered":"
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In the realm of global large-scale infrastructure\u2014including oil and gas transmission, offshore engineering, and water conservancy projects\u2014submerged arc welded steel pipes serve as the indispensable “arteries” that underpin modern energy and utility networks. Among all kinds of welded pipes, longitudinal submerged arc welded pipe (LSAW pipe) and spiral submerged arc welded pipe (SSAW pipe) are two main categories of large diameter steel pipe<\/strong>. Although both of them use submerged arc welding technology, their production methods are fundamentally different, resulting in obvious differences in performance, durability and applicability in key applications. This article dissects the core disparities between these two manufacturing processes and reveals the extreme, high-stakes operating conditions where LSAW Pipe is not merely a preferred choice but an absolutely irreplaceable solution. As a leading Chinese fabricant de tubes en acier<\/strong>, Hebei Allland Steel Pipe (Allland Pipes) employs cutting-edge JCOE forming technology to produce premium LSAW Pipe that meets the most stringent international standards, offering unparalleled reliability for mission-critical projects worldwide.<\/p>\n\n

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1<\/span>Core Production process of LSAW and SSAW steel pipes<\/a><\/span><\/div>\n
2<\/span>In-Depth Multi-Dimensional Comparison: LSAW vs. SSAW<\/a><\/span><\/div>\n
3<\/span>The Core Focus: When LSAW Pipe Is Absolutely Irreplaceable<\/a><\/span><\/div>\n
4<\/span>How to Choose a Suitable Pipe for Your Project<\/a><\/span><\/div>\n
5<\/span>Questions fr\u00e9quemment pos\u00e9es<\/a><\/span><\/div>\n
6<\/span>Conclusion<\/a><\/span><\/div>\n<\/div>\n<\/div>\n

Core Production process of LSAW and SSAW steel pipes<\/strong><\/h2>\n\n

What Is LSAW Pipe? (Longitudinal Submerged Arc Welding & JCOE Technology<\/strong>)<\/strong><\/h3>\n\n

Longitudinal submerged arc welded pipe is made of high quality thick steel plates as the main raw material. The industry-leading JCOE process (adopted by Allland Pipes\u00a0because of its accuracy and consistency) includes four key successive stages: J-forming, C-forming, O-forming and Mechanical Expansion.<\/p>\n\n

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  1. Steel plate preparation: The original steel plate is subjected to strict ultrasonic testing (UT) to detect internal defects, and then edge milling is carried out to ensure accurate width, parallelism and the best groove geometry for welding.<\/li>\n\n
  2. Pre-Bending: The plate edges are pre-bent to achieve the required curvature, laying the foundation for uniform cylindrical forming.<\/li>\n\n
  3. JCOE Forming: The plate is progressively shaped: first into a “J” profile on one half, then a “C” profile on the other, and finally closed into a full circular “O” shape via powerful hydraulic presses.<\/li>\n\n
  4. Welding: After tack welding, multi-wire submerged arc welding is used to weld the longitudinal seam from the inner and outer surfaces to ensure deep penetration and structural integrity.<\/li>\n\n
  5. Mechanical expansion: Mechanical expansion of the finished pipe to the final diameter. This key step improves the dimensional accuracy, perfects roundness, and significantly reduces residual stresses in the pipe.<\/li>\n<\/ol>\n\n

    The defining characteristics of LSAW <\/strong>p<\/strong>ip\u00e9<\/strong>\u00a0are its short, straight longitudinal weld seam, exceptional dimensional precision (including outstanding roundness and straightness), and minimal residual stress\u2014attributes that directly translate to superior mechanical performance in demanding environments.<\/p>\n\n

    What Is SSAW Pipe? (Spiral Submerged Arc Welding Technology<\/strong>)<\/strong><\/h3>\n\n

    In contrast, SSAW pipes are made of continuous hot-rolled steel coils. The process is a continuous, high-volume operation.<\/p>\n\n

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    1. Unwinding and leveling: Unwinding and leveling the steel coil to eliminate bending.<\/li>\n\n
    2. Spiral forming: The flattened steel strip is sent to a series of rollers, which bend the steel strip into a spiral shape at a controlled angle.<\/li>\n\n
    3. Spiral welding: The spiral weld is continuously welded from the inside and outside by submerged arc welding to form a long spiral weld around the circumference of the pipe.<\/li>\n\n
    4. Sizing and cutting: Cut the formed pipe\u00a0into required length, and carry out basic sizing and testing.<\/li>\n<\/ol>\n\n

      Tubes SSAW<\/strong>\u00a0are characterized by their long spiral welds (usually 1.5\u20133 times the length of the pipe), higher production efficiency in large diameter and medium and low pressure applications, and inherent flexibility in adjusting the diameter of the pipe. However, the spiral forming process will leave high residual stresses, and the long weld presents a large area which is easy to produce potential defects.<\/p>\n\n

      In-Depth Multi-Dimensional Comparison: LSAW vs. SSAW<\/strong><\/h2>\n\n

      The following table summarizes the basic differences between LSAW pipe\u00a0and SSAW pipe\u00a0in key performance indexes:<\/p>\n\n

      \n\n\n\n\n\n\n\n\n\n\n\n\n\n
      Comparison Parameter<\/strong><\/td>\nTube LSAW<\/strong><\/td>\nTube SSAW<\/strong><\/td>\n<\/tr>\n
      Mati\u00e8res premi\u00e8res<\/strong><\/td>\nThick, discrete steel plates (up to 50mm+ thickness)<\/td>\nContinuous hot-rolled steel coils (typically \u226425mm thickness)<\/td>\n<\/tr>\n
      Soudure<\/strong><\/td>\nShort, straight longitudinal seam (parallel to pipe axis)<\/td>\nLong, helical\/spiral seam (wraps around pipe)<\/td>\n<\/tr>\n
      Longueur de la soudure<\/strong><\/td>\nEqual to pipe length (e.g., 12m seam for 12m pipe)<\/td>\n1.5\u20133x pipe length (e.g., 18\u201336m seam for 12m pipe)<\/td>\n<\/tr>\n
      Max Wall Thickness<\/strong><\/td>\nUp to 60mm (ideal for high-pressure steel pipe<\/strong>)<\/td>\nTypically limited to \u226425mm<\/td>\n<\/tr>\n
      Residual Stress<\/strong><\/td>\nVery low (eliminated via mechanical expansion)<\/td>\nHigh (retained from spiral forming)<\/td>\n<\/tr>\n
      Pr\u00e9cision dimensionnelle<\/strong><\/td>\nExcellent (\u00b10.2% straightness, perfect roundness)<\/td>\nGood (variable ovality, lower straightness precision)<\/td>\n<\/tr>\n
      Defect Probability<\/strong><\/td>\nLow (shorter seam, easier NDT inspection)<\/td>\nHigher (longer seam, complex spiral geometry)<\/td>\n<\/tr>\n
      Pression nominale<\/strong><\/td>\nUltra-high (ideal for high-pressure steel pipe)<\/td>\nMedium to low pressure only<\/td>\n<\/tr>\n
      Fatigue Life<\/strong><\/td>\nSuperior (excellent resistance to cyclic stress)<\/td>\nModerate (lower stress resistance)<\/td>\n<\/tr>\n
      Typical Cost<\/strong><\/td>\n30\u201350% higher (material & process complexity)<\/td>\nLower (higher efficiency, coil material)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n\n

      Data source: Piping Industry Technical Reference (2026)<\/p>\n\n

      1. Weld Length & Defect Risk<\/strong><\/h3>\n\n

      The most profound difference lies in weld geometry. The weld length of SSAW pipes is typically 1.5\u20133 times that of Tubes LSAW<\/a>. A longer weld means that the area susceptible to welding defects (such as porosity, slag inclusions or micro-cracks) is significantly larger. For LSAW Pipe, the short, straight seam simplifies non-destructive testing (NDT) and ensures far fewer potential failure points\u2014a critical factor in safety-critical applications.<\/p>\n\n

      2. Load-Bearing Capacity and Wall Thickness Limits<\/strong><\/h3>\n\n

      Longitudinal submerged arc welded pipe can be made of ultra-thick steel plates (up to 50-60 mm thick), which can withstand extreme internal pressures required for high-pressure steel pipe<\/strong>\u00a0applications. SSAW pipe is limited by the maximum thickness of available steel coils (usually \u2264 25 mm), which limits its pressure bearing capacity and excluding it from ultra-high pressure application.<\/p>\n\n

      3. Residual Stress and Fatigue Resistance<\/strong><\/h3>\n\n

      The mechanical expansion stage in LSAW Pipe production is transformative: it relieves nearly all residual stresses formed during forming and welding. This makes the pipe\u00a0have excellent resistance to fatigue failure caused by cyclic pressure, thermal fluctuations or external forces. SSAW pipe retains significant forming-induced stresses, making it more vulnerable to crack propagation and fatigue degradation over time.<\/p>\n\n

      4. Geometric Dimensional Precision<\/strong><\/h3>\n\n

      LSAW <\/strong>p<\/strong>ip\u00e9<\/strong>\u00a0delivers unmatched roundness and straightness, ensuring seamless field-fit welding and minimizing stress concentrations at joints. SSAW pipes usually show slight deviations in roundness and straightness, which can complicate installation and reduce the integrity of joints in demanding installations.<\/p>\n\n

      The Core Focus: When LSAW Pipe Is Absolutely Irreplaceable<\/strong><\/h2>\n\n

      Bien que Tube d'acier SSAW<\/a> perform well in low-pressure applications which are cost-sensitive, longitudinal submerged arc welding pipes are the only feasible choice under the following extreme and high-consequence operating conditions.<\/p>\n\n

      1. High-Pressure & Ultra-High-Pressure Oil&Gas Transmission Lines<\/strong><\/h3>\n\n

      Pour high-pressure steel pipe<\/strong>\u00a0in long-distance pipes (especially API 5L\u00a0X70, X80, and higher steel grades) traversing populated Class 3\/4 areas or requiring maximum burst pressure resistance, LSAW Pipe is the non-negotiable standard. Its short defect-resistant welding, ultra-thick wall capacity and 100% equivalent welding strength of base material eliminate the risk of catastrophic failure, which increases exponentially when SSAW pipes are used under such extreme pressures.<\/p>\n\n

      2. Deep-water and Offshore Platform Installations<\/strong><\/h3>\n\n

      in submarine environments, offshore pipelines\u00a0must be able to resist the damage of external hydrostatic pressure (which can exceed 15 MPa at depths of 1,500 meters, and even higher in deeper zones) and can withstand the continuous fatigue caused by ocean currents and wave movements. Under this multi-axial cyclic stress, the long spiral weld of SSAW pipe becomes the weak point of the structure, making it more prone to failure. LSAW Pipe’s uniform stress distribution, minimal residual stress, and exceptional collapse resistance make it the highly preferred choice for critical offshore pipelines under strict DNV-OS-F101 and API 5L<\/a> PSL 2 offshore specifications.<\/p>\n\n

      3. <\/strong>Extremely Cold <\/strong>a<\/strong>nd Seismically Active Zones<\/strong><\/h3>\n\n

      In permafrost regions or earthquake-prone regions, pipes are faced with intense ground motion, thermal cycle and dynamic loads. The excellent low-temperature toughness (Charpy impact energy \u2265 40 Joule at-20 degrees Celsius) and strain-based design ability of longitudinal submerged arc welded pipe make it not break when deformed. SSAW pipe has low impact resistance and high residual stress, and brittle fracture or joint failure is easy to occur under these geo-mechanical stresses.<\/p>\n\n

      4. Critical Structural Piling for Mega-Project<\/strong><\/h3>\n\n

      For large-diameter large diameter steel pipe<\/strong>\u00a0used as bearing piles in offshore wind farms, cross-sea bridges, and high-rise foundations, LSAW Pipe delivers unparalleled axial and lateral load-bearing capacity. Its uniform wall thickness, perfect roundness and uniform stress distribution ensure structural stability under large-scale compression and bending load\u2014making it the preferred choice over standard SSAW pipes when dealing with unprecedented axial loads.<\/p>\n\n

      How to Choose a Suitable Pipe for Your Project<\/strong><\/h2>\n\n

      Optimal SSAW Pipe Applications<\/strong><\/h3>\n\n

      Tube SSAW<\/strong>\u00a0is the economical choice for:<\/p>\n\n