1. ERW steel pipe -- resistance welded steel pipe
Production technology
ERW (Electric Resistance Welded) steel pipes are welded by using the resistance heating principle. After the steel sheet or steel coil is cold-bent to form pipes, current and pressure are applied to the joints of the pipes to partially heat up the joints and weld them. There is no need to heat the entire workpiece during the entire process, allowing for fast and efficient welding.
Structure and characteristics
Joint characteristics: The weld is generally located on the inside or outside of the pipe wall, the appearance is smooth, and the seam line is hidden.
Scope of application: Suitable for small and medium diameter pipelines, mostly used in water, gas, light medium transportation and structural profiles.
Advantages: simple process, high production efficiency, low cost.
Limitations: When the pipe diameter and wall thickness requirements are large, the pressure and mechanical properties of ERW steel pipes may be limited.
2. SSAW steel pipe -- spiral welded steel pipe
Production technology
SSAW (Spiral Submerged Arc Welded) steel pipes are made of spiral welding process. First, the steel strip is spirally wound into a tube, and then welded along the spiral seam by submerged arc welding. This method is especially suitable for manufacturing large diameter and long span pipes.
Structure and characteristics
Welding features: The welds on the pipe body are distributed in a spiral shape, and the overall appearance is closely integrated with the curve of the pipe body.
Scope of application: Mainly used in oil, natural gas and water conservancy and other fields for large diameter, high strength pipeline demand.
Advantages: strong adaptability, can produce large diameter, thick wall steel pipe; High strength of welded joints.
Limitations: Spiral welds have high requirements for process control and large investment in production equipment.
3. LSAW steel pipe -- straight seam welded steel pipe
Production technology
LSAW (Longitudinal Submerged Arc Welded) steel pipe is directly processed by flat plate, the steel plate is cut to a certain size, and is made by longitudinal submerged arc welded. Unlike SSAW, the weld of LSAW steel pipe is in a straight line along the length of the pipe.
Structure and characteristics
Welding characteristics: the position of the weld is fixed, and the welding process is mature, and the quality of the weld is stable.
Scope of application: Mainly used in oil and gas pipelines, offshore engineering and large-scale industrial facilities, especially under the requirements of high pressure transportation has obvious advantages.
Advantages: simple structure, good joint strength, suitable for high-pressure, high-temperature environment.
Limitations: Because the process is more complex, the production cost is relatively high, and the processing equipment requirements are strict.
4. Comparison and application of various types of welded steel pipes
Diameter and wall thickness: ERW steel pipes are suitable for small and medium diameters with thin wall thickness, while SSAW and LSAW steel pipes are more suitable for large diameters and thicker walls.
Bearing capacity: LSAW steel pipe usually has a higher bearing capacity due to its longitudinal welding process; SSAW steel pipes also have high strength, but their spiral welds require special attention to process control.
Production cost and efficiency: ERW process is simple, low cost, high production efficiency; Relatively speaking, SSAW and LSAW processes are complex and equipment investment is large, but they can meet the needs of high strength and large diameter pipes in special fields.
Application: ERW steel pipe is widely used in municipal pipe network, building structure and light industrial products; SSAW and LSAW steel pipes play a key role in oil, gas, offshore engineering and other fields.
5. Summarize
As an important industrial product, welded steel pipe has various kinds and wide application. ERW steel pipe is popular for its simple process and high efficiency; The SSAW steel pipe is suitable for demanding conveying systems with the advantage of manufacturing large diameter pipes. LSAW steel pipe, with its excellent joint strength and adaptability to high pressure environment, plays an important role in oil and gas transportation and major projects. Understanding their respective processes and characteristics is helpful to make more reasonable choices in engineering material selection and design.
Through continuous improvement of the welding process and strengthening of quality control, the future welded steel pipe will play a greater role in a wider range of fields and promote the sustainable development of modern industry.