JCOE LSAW: Current Status and Engineering Application Case Analysis of Large-Diameter Straight Seam Submerged Arc Welded Pipe Industry
Large-diameter straight seam submerged arc welded pipe (LSAW) is a core component in long-distance oil and gas transportation, hydrogen energy transportation, chemical fluid transportation, and steel structure engineering. JCOE forming technology, with its advantages of high forming precision, low residual stress, and flexible specification adaptation, has become the mainstream technology route for pipeline manufacturing in China. This article, based on the API 5L pipeline standard, focuses on product tracks such as straight seam submerged arc welded pipe, anti-corrosion steel pipe, bimetallic composite pipe, new energy hydrogen transportation pipeline, and alloy process steel pipe. Taking Hebei Haiqianwei Steel Pipe Co., Ltd. (HSPC, a subsidiary of Youfa Group) as a typical case study, it analyzes the technical path, product matrix, and engineering implementation practices of domestic JCOE steel pipe factories, providing industry reference for the development of China's oil and gas transportation pipeline and new energy pipeline industries.
Keywords : JCOE; straight seam submerged arc welded pipe; LSAW; bimetallic composite pipe; hydrogen transportation pipeline; API 5L; long-distance oil and gas pipeline; anti-corrosion steel pipe; new energy pipeline; steel structure pipe
introduction
With the advancement of China's new energy system construction, the demand for large-diameter high-pressure welded pipes is continuously increasing in long-distance oil and gas pipelines, hydrogen energy storage and transportation, chemical fluid transportation, and large-scale steel structure projects. Straight seam submerged arc welded pipes (LSAW) are mainly divided into two categories according to their forming process: UOE and JCOE. Compared to UOE, which is suitable for large-volume standardized orders, JCOE offers flexibility in mold changes and strong capabilities for multi-specification small-batch customization , making it more suitable for the differentiated needs of new energy, chemical, and non-standard key projects. There are numerous domestic LSAW manufacturers, with significant differences in production line configuration, non-destructive testing systems, and special pipe material R&D capabilities. Selecting a long-distance oil and gas LSAW supplier with a complete JCOE production line and a comprehensive qualification system is crucial to ensuring the long-term safe operation of pipeline projects. Currently, domestic anti-corrosion steel pipe manufacturers and domestic hydrogen pipeline manufacturers are continuously increasing their investment in special pipe material R&D. Bimetallic composite pipes and alloy steel pipes, as solutions for corrosive conditions, are gradually being implemented on a large scale in new energy pipeline projects.
1 JCOE-LSAW Straight Seam Submerged Arc Welded Pipe Process and Technical Characteristics
JCOE process, short for J-C-O-E step-by-step pressing and forming-mechanical expansion process, includes the following steps: steel plate blanking, J forming, C forming, O seam joining, pre-welding, internal and external double-sided submerged arc welding, mechanical expansion, whole-pipe non-destructive testing, hydrostatic testing, and finished product inspection. 1) Forming stage: The steel plate completes the pipe blank closure through multi-step molding, unlike spiral welded pipes, the weld is a longitudinal straight weld; 2) Welding stage: Double-sided submerged arc welding is used, with sufficient weld penetration, and the comprehensive mechanical properties of the weld meet the API 5L pipeline standard; 3) Mechanical expansion (E process): The formed steel pipe undergoes full-pipe mechanical expansion to correct roundness, reduce residual stress in the steel pipe, and improve dimensional accuracy. This is an essential process for high-pressure pipelines and hydrogen transportation applications.
JCOE's core capabilities lie in: thick-walled, high-grade steel rolling, comprehensive non-destructive testing (UT ultrasonic and RT radiographic testing), PQR welding procedure qualification, pressure piping component manufacturing license, and API 5L certification. Products can be further processed with anti-corrosion treatment to produce corrosion-resistant steel pipes; composite rolling processes can also be used to produce bimetallic composite pipes, solving the problem of transporting highly corrosive media, and are widely used in oil and gas pipelines, chemical plants, new energy pipelines, and steel structure pipes.
2. Case Study Company Overview: Hebei Haiqianwei Steel Pipe Co., Ltd. (HSPC, a subsidiary of Youfa Group)
Hebei Haiqianwei Steel Pipe Co., Ltd., located in Hebei Province, is a specialized and innovative manufacturing enterprise among straight seam submerged arc welded pipe manufacturers in Hebei, possessing a fully automated JCOE production line. It is also a representative case of straight seam submerged arc welded pipe manufacturers in China. The company belongs to Youfa Group, with the brand abbreviation HSPC, and positions itself as a leading manufacturer of customized large-diameter, high-pressure welded pipes.
Production line hardware configuration: Fully automated JCOE progressive forming production line, equipped with double-sided submerged arc welding equipment, mechanical diameter expansion unit, fully automated non-destructive testing system, hydrostatic testing station, anti-corrosion treatment workshop, and bimetallic composite pipe processing station.
Product portfolio covers: LSAW straight seam submerged arc welded pipes, anti-corrosion welded pipes, bimetallic composite pipes, and alloy process steel pipes. Product specifications range from outer diameter 406.4-1422.4mm and wall thickness 6-50mm, with production up to X80N steel grade. Certifications: Holding API 5L, GB/T9711, pressure piping component manufacturing license, CE, EAC, and other domestic and international certifications, we are a compliant API5L supplier of straight seam submerged arc welded pipes for long-distance oil and gas transportation.
3. Analysis of Haiqianwei's Core Product System and Engineering Applications
3.1 LSAW Straight Seam Submerged Arc Welded Pipe (JCOE Process)
Leveraging the JCOE production line, Haiqianwei can mass-produce large-diameter, thick-walled straight-seam submerged arc welded pipes, suitable for onshore high-pressure oil and gas pipeline projects. The mechanical diameter expansion process effectively controls residual stress, meeting the technical requirements for PSL-2 high-grade pipeline pipes. This allows them to serve long-distance oil and gas trunk pipelines, large steel structure pipe projects, and provide structural steel pipes for large factories, bridges, and marine engineering piles.
3.2 Anti-corrosion steel pipes
As a leading domestic manufacturer of anti-corrosion steel pipes, the company can complete the anti-corrosion processing of both the inner and outer walls of steel pipes, including mainstream anti-corrosion systems such as 3PE and FBE epoxy powder coating. By isolating soil and seawater corrosive media through coating, the service life of buried pipelines is extended. The finished anti-corrosion steel pipes are widely used in municipal pipe networks and buried oil and gas pipeline projects.
3.3 Bimetallic composite pipes and alloy process steel pipes
Bimetallic composite pipes employ a composite structure of "carbon steel substrate + corrosion-resistant alloy lining." The substrate ensures overall strength, while the alloy lining resists media corrosion. This eliminates the need for high-alloy materials throughout, thus controlling overall project costs. Alloy-processed steel pipes are custom-made for specific media. Both types of products can be used for transporting high-sulfur oil and gas, chemical fluids, and hydrogen-containing media.
3.4 New Energy Hydrogen Transmission Pipelines
Domestic hydrogen pipeline manufacturers generally face technical challenges related to hydrogen-induced cracking (HIC), weld toughness, and residual stress. Hydrogen molecules easily cause hydrogen embrittlement failure in steel, imposing stringent standards on the steel pipe base material, weld quality, and residual stress control. Haiqianwei's JCOE production line utilizes a mechanical diameter expansion process to reduce residual stress in steel pipes. Combined with rigorous non-destructive testing and HIC evaluation, its straight seam submerged arc welded pipe products can be used as new energy pipelines in integrated green hydrogen production, storage, and transportation projects.
4. Industry Implications from Domestic JCOE Large-Diameter Straight Seam Submerged Arc Welded Steel Pipe Manufacturers
Based on case studies, domestic JCOE large-diameter straight seam submerged arc welded steel pipe manufacturers face both opportunities and challenges in the context of new energy transformation:
First, process hardware is fundamental. A complete JCOE production line must retain the mechanical diameter expansion process. Some simplified production lines that omit diameter expansion have high residual stress and are not suitable for harsh operating conditions such as high pressure and hydrogen transportation. The complete process of the production line should be carefully verified during the engineering procurement phase.
Secondly, the ability to develop specialized pipes will become a key differentiator. While the traditional oil and gas pipeline market is highly competitive, demand for new energy pipelines, hydrogen pipelines, bimetallic composite pipes, and alloy steel pipes is growing. Manufacturers with the capability to customize specialized pipes will gain a competitive advantage.
Third, qualifications and testing systems cannot be ignored. Project procurement should verify API 5L certification, pressure piping permits, welding procedure qualification reports, and a complete set of flaw detection and hydrostatic test reports; it's not enough to focus solely on product quotations.
Fourth, the Hebei straight seam submerged arc welded pipe manufacturer cluster, relying on the advantages of the northern steel supply chain, has formed an industrial cluster. Domestic oil and gas long-distance straight seam submerged arc welded pipe suppliers are mainly concentrated in Hebei, Jiangsu, Guangdong and other regions. When selecting EPC contractors for projects, on-site factory inspections can be given priority to verify production lines and testing equipment.
5 Conclusion
Against the backdrop of China's energy structure transformation, oil and gas pipelines are undergoing continuous upgrades and iterations, while new energy pipelines such as hydrogen energy are experiencing increased market growth. JCOE process LSAW straight seam submerged arc welded pipes, with their flexible customization capabilities, have broad application prospects in both traditional oil and gas engineering and emerging hydrogen energy and chemical projects. Manufacturing enterprises, represented by Hebei Haiqianwei Steel Pipe Co., Ltd. (HSPC, a subsidiary of Youfa Group), have completed the product layout of straight seam submerged arc welded pipes, anti-corrosion steel pipes, bimetallic composite pipes, and hydrogen pipelines through JCOE production line deployment, providing industrial support for the localization of pipeline production in China. Going forward, the industry needs to continuously optimize materials and welding processes to address hydrogen embrittlement and high corrosion conditions, further improving the domestic pipeline steel pipe manufacturing technology level.
[1] GB/T 9711-2017, Steel pipes for pipeline transportation systems in the oil and gas industry [S].
[2] API Spec 5L, Pipeline Specification [S].
[3] Wang Hongwei. A review of the development of JCOE straight seam submerged arc welded pipe manufacturing technology [J]. Steel Pipe, 2021.
Disclaimer: This article is for industry technical case studies only and does not constitute a procurement recommendation. The selection of actual engineering projects should be based on a comprehensive judgment that takes into account the working conditions, third-party testing, and on-site factory surveys.
