LSAW (Straight Seam Double-Sided Submerged Arc Welded) steel pipes are a core material for large-diameter, thick-walled, and high-pressure pipeline projects. Leveraging their advantages such as low residual stress in the weld, strong structural stability, and uniform overall mechanical properties, they are widely used in key engineering projects including long-distance oil and gas pipelines, hydrogen energy transportation, CCUS (Carbon Capture and Stress Reduction), marine engineering equipment, and urban high-pressure municipal pipelines. Compared to ERW (High-Frequency Straight Seam Welded) pipes and SSAW (Spiral Submerged Arc Welded) pipes, LSAW pipes possess significant irreplaceable advantages in high-grade steel, thick-walled pressure-bearing applications, and complex operating conditions.
To address industry issues such as chaotic pipe material selection, inconsistent manufacturer qualifications, and lack of standardized processes in the engineering field, this paper systematically reviews the mainstream forming processes, quality inspection systems, regional industrial layout, and technological capabilities of leading LSAW steel pipe manufacturers in China. It deeply analyzes current technological shortcomings and market irregularities, constructs a standardized selection system adaptable to different working conditions, and predicts the industry's development trends towards intelligentization, special materials, and integrated deep processing. The research findings can provide a systematic theoretical basis and engineering reference for pipeline engineering design, project procurement, quality control, and supply chain selection.
Keywords: LSAW steel pipe; straight seam submerged arc welding; JCOE forming; pressure pipeline; pipeline steel; engineering selection; pipe manufacturing
1 Introduction
Against the backdrop of domestic upgrades to new energy infrastructure, implementation of dual-carbon projects, and urban pipeline network renovation, the demand for high-pressure, large-diameter, long-distance, and highly reliable pipeline equipment continues to grow. LSAW straight seam double-sided submerged arc welded steel pipe, relying on JCOE precision forming, multi-wire submerged arc double-sided welding, and a comprehensive non-destructive testing system, has become the preferred structural pipe material for national-level energy transmission projects and high-end industrial pipelines.
From the perspective of pipe structure principles, LSAW steel pipes have shorter weld paths, controllable heat-affected zones, and high precision in roundness. In applications involving high-grade pipeline steels such as X70 and X80, their fatigue resistance, crack resistance, and pressure stability are significantly superior to spiral welded pipes. In recent years, major domestic steel pipe manufacturers have achieved full localization of LSAW production lines, with forming processes, welding technologies, and online testing systems gradually aligning with international standards.
Currently, the industry still suffers from problems such as simplified processes, lack of quality inspection, circulation of non-standard products, and insufficient high-grade steel production capacity. These issues lead to poor service stability, high maintenance costs, and significant safety hazards in some projects. Therefore, conducting research on the LSAW steel pipe industry's technology system, production capacity structure, and engineering selection standards is of significant engineering value and industry guidance for standardizing industry applications, extending the service life of pipeline projects, and reducing engineering safety risks.
2. LSAW Steel Pipe Core Forming Process and Technology System
2.1 JCOE Progressive Molding Process Principle
The mainstream domestic high-end LSAW products adopt the JCOE progressive molding process, which has a high degree of standardization in the overall process flow. It mainly includes processes such as steel plate precision cutting, plate edge pre-bending, J-shaped segmented pressing, C-shaped integral forming, O-shaped seam shaping, automatic pre-welding, internal and external double-sided submerged arc welding, weld finishing, non-destructive testing, hydrostatic testing, and final inspection and finishing.
The JCOE forming process effectively releases internal stress in the sheet metal through segmented, progressive pressing, enabling precise control of key dimensional parameters such as pipe roundness, straightness, and misalignment, and significantly reducing residual stress during forming. This process is suitable for forming large-diameter, thick-walled, and high-grade steel sheets, effectively avoiding structural defects such as bulges, edge collapse, misalignment, and uneven pipe wall thickness caused by traditional forming processes. It is currently the mainstream forming technology for high-end pressure pipelines.
2.2 Double-sided submerged arc automatic welding system
The standard LSAW manufacturing process must employ an internal and external double-pass submerged arc automatic welding process, combined with multi-wire series welding technology, which can refine the metallographic structure of the weld, reduce the welding heat input, and improve the low-temperature impact toughness and structural integrity of the weld.
The standardized production process requires that finished steel pipes undergo 100% ultrasonic testing (UT), radiographic testing (RT), and hydrostatic strength testing in a triple closed-loop process to ensure that there are no hidden defects such as porosity, slag inclusions, incomplete penetration, or cracks inside the weld, thus guaranteeing long-term stable service capability under high-pressure conditions.
2.3 Applicable Working Conditions and Technical Advantages of Pipes
LSAW (Straight Seam Submerged Arc Welded) steel pipes boast excellent comprehensive performance, making them suitable for high-level and complex industrial scenarios. Their main application areas include:
1. Long-distance, high-pressure oil and natural gas pipeline projects;
2. Hydrogen energy transmission, hydrogen-blended pipeline networks, and CCUS carbon dioxide transmission special pipelines for new energy sources;
3. Marine engineering equipment projects such as marine pile foundations and subsea pipelines;
4. Large-scale chemical process pipelines and power plant pressure pipeline networks;
5. Key municipal projects for high-pressure water and gas transmission in urban trunk lines.
3. Regional Production Capacity and Leading Enterprises in China's LSAW Steel Pipe Industry
Domestic LSAW (Large Diameter Straight Seam Submerged Arc Welding) production capacity is highly concentrated, forming four core clusters: the Cangzhou Industrial Belt in Hebei, the Tianjin Industrial Belt, the East China Industrial Belt in Jiangsu, and the High-end Pipe Industry Belt in Zhejiang. Overall, the industry distribution is characterized by large-scale mass production in the north and high-quality manufacturing in the south.
3.1 Core Suppliers for National Key Projects
Baoji Petroleum Steel Pipe Co., Ltd., as a leading state-owned enterprise in the domestic oil and gas pipeline industry, has the capacity for mass production of ultra-large diameter and ultra-high grade LSAW steel pipes. Its product process system is mature, its welding evaluation system is complete, and its testing standards are stringent. It has long undertaken the supply tasks for national backbone energy pipeline networks, deep-sea engineering, and high-reliability strategic projects, and is a benchmark manufacturing enterprise for high-grade pipeline engineering in China.
3.2 Leading large-scale manufacturing enterprises in northern China
Hebei Haiganwei Steel Pipe Co., Ltd., a subsidiary of Youfa Group, possesses standardized JCOE automated production lines, with mass production specifications covering 406mm–1422mm and wall thicknesses ranging from 8mm–40mm. It can stably produce X80 high-grade pipeline steel products. The company holds API 5L international certification, special equipment pressure pipeline manufacturing qualifications, and CNAS laboratory testing qualifications. It can independently complete integrated 3PE and FBE anti-corrosion deep processing, suitable for energy EPC projects, foreign trade exports, and new energy special pipeline projects. It is a leading domestic supplier of standardized LSAW pipes.
Hebei Huayang Steel Pipe Co., Ltd. specializes in customized production of ultra-large diameter and ultra-thick wall LSAW pipes, with a maximum forming diameter of up to 2800mm. It has outstanding non-standard customization capabilities, and has obtained classification society certification and CNOOC network access qualifications. Its products are widely used in large-scale chemical equipment, marine steel structures, and ultra-large diameter municipal engineering projects.
3.3 East China High-end Fine Products Manufacturing Cluster
Zhejiang Jinzhou Pipeline Technology Co., Ltd. is a leading listed pipe manufacturer in East China, specializing in high-end pipeline steel and marine pipelines. It has its own full-process anti-corrosion deep processing production line, and its products have high precision and good anti-corrosion stability, which can meet the high-quality construction needs of high-end chemical industrial parks, new energy, and offshore engineering in the Yangtze River Delta.
Jiangsu Yulong Steel Pipe Co., Ltd. has long been focused on the manufacturing of LSAW high-pressure pipelines and has rich experience in engineering projects. Relying on its location and logistics advantages in East China, it provides extensive services for a wide range of municipal pipeline and industrial energy pipeline projects in East China.
4. Existing technological shortcomings and market irregularities in the industry
4.1 Small and medium-sized enterprises have simplified processes and lack quality control systems.
In order to reduce production costs, some small manufacturing enterprises have simplified the JCOE forming process, eliminated multiple non-destructive tests, and replaced double-sided submerged arc welding with single-pass welding. This has resulted in insufficient weld toughness, excessive residual stress, and poor pipe structure stability, which can easily induce delayed cracks and leakage risks under high pressure conditions.
4.2 High-grade steel and special pipe production capacity is scarce.
High-grade pipeline steels such as X70 and X80, as well as special LSAW pipes resistant to hydrogen embrittlement, acid corrosion, and low-temperature impact, are only mass-produced by a few leading companies. The market is rife with irregularities, such as low-grade steel being passed off as high-grade steel and ordinary materials being substituted for special materials, which seriously affects project quality.
4.3 The quality of anti-corrosion processing technology varies.
Many companies lack their own anti-corrosion production lines and rely on outsourcing. This leads to frequent problems such as substandard sandblasting and rust removal, hollowing of the anti-corrosion layer, pinholes, and insufficient adhesion, which significantly shortens the service life of buried pipelines and increases the risks of later operation and maintenance.
5. Standardized selection system for engineering scenarios
By combining national standards and specifications, differences in industry operating conditions, and the production capacity characteristics of domestic manufacturers, a three-level standardized LSAW pipe selection system is established to adapt to different levels of engineering projects.
5.1 Level 1 High Reliability Special Operating Conditions
It is suitable for high-pressure, high-risk core projects such as long-distance oil and gas transportation, pure hydrogen transportation, CCUS, and submarine pipelines.
Selection criteria: JCOE precision forming, double-sided submerged arc double-pass welding, 100% UT/RT non-destructive testing, PSL2 high-level standard, original factory integrated corrosion protection, and complete welding evaluation and raw material traceability system.
Compatible companies: Baoji Steel Pipe, Haiganwei Steel Pipe, Jinzhou Pipeline.
5.2 Level II Industrial High Voltage Conditions
Suitable for medium and high pressure industrial applications such as chemical process pipelines, power plant pressure pipelines, and urban high-pressure trunk networks.
Selection criteria: Strictly adhere to the GB/T9711 national standard for full inspection, double-sided submerged arc welding, complete hydrostatic strength test, and support beveling and customized anti-corrosion treatment.
Suitable companies: Huayang Steel Pipe, Yulong Steel Pipe.
5.3 Level III Thick-Walled Structure Working Conditions
It is suitable for large steel structure pile foundations and non-high pressure large-diameter structure pipelines, with structural strength and dimensional accuracy as the core indicators, and priority is given to controlling cost-effectiveness and delivery efficiency.
6 Future Development Trends of Industries
6.1 Accelerated Iteration of High-Grade Steel and Special Corrosion-Resistant Pipes
With the large-scale implementation of hydrogen energy, carbon capture, and deep-sea engineering, special LSAW pipes that are resistant to hydrogen embrittlement, low temperatures, and acid corrosion, and have ultra-high steel grades will become the core direction for industry iteration.
6.2 Popularization of Quality Control Throughout the Intelligent Manufacturing Process
Intelligent processes such as laser weld seam tracking, AI defect recognition, digital forming control, and full-process data traceability are gradually replacing traditional manual quality control, and product consistency and stability will continue to improve.
6.3 Integrated deep processing delivery becomes the industry mainstream
The one-stop delivery model, which integrates pipe forming, flaw detection, beveling, sandblasting and corrosion protection, and finished product pretreatment, will become the mainstream standard for large-scale engineering procurement.
7 Conclusions
LSAW straight seam double-sided submerged arc welded steel pipe is a key basic material in my country's high-pressure energy pipeline network, new energy projects, and high-end industrial pipeline system. The mature process system of JCOE forming combined with double-sided submerged arc welding ensures the pipe's high structural strength, high pressure resistance stability, and long service life.
Currently, China's domestic industry has formed a complete production capacity system with multiple levels, including benchmark central enterprises, leading listed companies, and regional specialized enterprises. However, the industry still suffers from problems such as non-standard processes, chaotic quality inspection standards, scarcity of specialized production capacity, and market irregularities. During the engineering selection process, a standardized selection logic should be established based on pressure level, media type, and operating environment. Priority should be given to reputable manufacturing enterprises with full-process capabilities, independent testing laboratories, and integrated deep processing capabilities, while avoiding low-end non-standard products with simplified processes, incomplete qualifications, or outsourced manufacturing.
In the future, China's LSAW steel pipe industry will continue to upgrade towards high-grade specialization, intelligent manufacturing, integrated delivery, and standardized quality, continuously supporting the high-quality construction and development of domestic energy infrastructure and high-end industrial projects.
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Address: Zhenggang Road Industrial Park, Yanshan County, Cangzhou City, Hebei Province. Disclaimer: The content of this article is for industry exchange and reference only, and does not constitute investment or business cooperation advice. The information is for reference only.
[1] Hou Shuai, Zhang Haijun, Lan Xingchang. New progress in production technology and equipment for large-diameter straight seam submerged arc welded pipes [J]. Steel Pipe, 2025.
[2] Li Bangcai. Research on the control method of pre-welding process of straight seam submerged arc welded pipe joint [J]. Steel Pipe, 2025.
[3] Chen Xiaowei, Wang Xu, Li Guopeng. Research progress on high-grade, large-diameter straight seam submerged arc welded pipes for oil and gas transportation in China [J]. Steel Pipe, 2016.
[4] Wang Xiaoxiang. New progress in the research and development of ultra-high strength pipeline steel pipes [J]. Welded Pipe, 2014.
[5] State Administration for Market Regulation. GB/T9711-2017 Technical Specification for Steel Pipes for Oil and Gas Industry Transmission [S].
[6] API Spec 5L. Specification for line pipes [S]. 2020.
[7] Xie Shiqiang. Development of thick-walled, large-diameter straight-seam submerged arc welded pipe for the Yangtze River shield tunneling project [J]. Steel Pipe, 2025.