Welded steel pipes for oil and gas transportation refer to welded steel pipes used for transporting oil, natural gas, and their products. This type of steel pipe is formed by rolling steel plates or steel strips into a tube through a welding process.
Welded steel pipes are mainly divided into straight seam welded pipes (LSAW), spiral submerged arc welding (SSAW), and high-frequency straight seam welded pipes (ERW) according to different welding methods. Welded steel pipes are widely used in oil and gas pipelines due to their excellent mechanical properties and corrosion resistance. The manufacturing process, advantages, application fields, and relevant standards of welded steel pipes for oil and gas transportation are introduced in this article.
Manufacturing processes
The manufacturing processes of welded steel pipes for oil and gas transportation mainly include the following:
High-frequency resistance welding (HFW): This method is suitable for manufacturing small-diameter pipelines. High-frequency current generates resistance heat at the contact point of the steel strip to melt it and applies pressure to form welding.
Spiral submerged arc welding (SSAW): This method is suitable for manufacturing large-diameter pipelines. After the steel plate is formed into a spiral shape by a forming machine, it is welded using submerged arc welding. The advantage of spiral submerged arc welding is that the welding seam is evenly distributed and can withstand significant pressure.
Straight seam submerged arc welding (LSAW): This method is also suitable for large-diameter pipelines. After the steel plate is formed into a straight seam pipeline by a forming machine, it is welded using submerged arc welding. The strength of straight seam welding is high and making it suitable for high-pressure environments.
Advantages
Welded steel pipes for oil and gas transportation have the following advantages:
High strength: The strength and durability of the welded steel pipe are ensured through an optimized welding process, enabling it to withstand high pressure and impact during transportation.
Corrosion resistance: The surface of the steel pipe is usually treated with anti-corrosion treatments, such as 3PE and epoxy powder coating, to enhance its corrosion resistance and adapt to complex geographical and climatic conditions.
Cost-effectiveness: Compared with seamless steel pipes, welded steel pipes have higher production efficiency and lower manufacturing costs, making them suitable for large-scale applications.
Flexibility: Welded steel pipes can be customized with various diameters and wall thicknesses according to different transportation needs, providing good adaptability.
Applications
Long-distance pipelines: Welded steel pipes are used for cross-regional and cross-border oil and gas pipelines to ensure energy security and stable supply.
Urban pipelines: Welded steel pipes are used for urban gas and heating pipelines to ensure the energy supply for urban residents.
Submarine pipelines: welded steel pipes are used for submarine pipelines in offshore oil and gas field development, maintaining stable operation in harsh marine environments.
Related standards
The production and use of welded steel pipes for oil and gas transportation need to comply with a series of international and national standards to ensure quality and safety, such as API 5L, ISO 3183, and GB/T 9711.
API 5L: A standard developed by the American Petroleum Institute, covering the specifications of steel pipes for oil and gas industry pipelines.
ISO 3183: A standard of the International Organization for Standardization, which specifies the technical requirements for steel pipes for oil and gas pipelines.
GB/T 9711: A Chinese national standard, applicable to steel pipes for oil and gas industry pipeline transportation systems.
