Characteristics of Submerged Arc Welding Steel Pipe

Summary

Submerged arc welding (SAW) steel pipes are essential in numerous industries, thanks to their unique production processes and characteristics. This article explores the differences between SAW and high-frequency welding steel pipes, offering a detailed understanding of their definitions, production methods, and standards. Discover the nuances that set these welding techniques apart and learn how to distinguish between them effectively.

What is Submerged Arc Welding (SAW) Steel Pipe?

Submerged arc welding (SAW) steel pipes feature a longitudinal weld, often referred to as a straight seam. When the diameter exceeds 914 mm, two welds are permissible. The welding process involves using a wire filler and flux protection, resulting in a robust and durable weld. The primary characteristic of SAW steel pipes is the use of wire arc hot melt, which ensures a strong bond.

Key Characteristics of SAW Steel Pipes

• Longitudinal Weld: A straight seam along the length of the pipe.
• Wire Filler and Flux Protection: Ensures a strong and durable weld.
• Diameter Flexibility: Can accommodate diameters greater than 914 mm with two welds.

Differences Between High-Frequency and Submerged Arc Welding Steel Pipes

Raw Materials and Production Processes

The primary differences between high-frequency (HF) and SAW steel pipes lie in their raw materials, forming processes, and welding techniques.

• SAW Steel Pipes: Utilize rolled plates with a minimum width of 1250 mm. The forming process, known as JCOE, involves cold stamping to gradually shape the steel sheet.
• HF Steel Pipes: Use wide strip steel with a width of up to 1500 mm. The forming process involves continuous extrusion and welding, resulting in a seamless and uninterrupted production line.

Welding Techniques

• SAW Welding: Uses the electrothermal effect to melt the welding wire and steel plate together, creating a filler weld.
• HF Welding: Relies on the high-frequency skin effect to rapidly heat the strip steel ends, which are then fused together under external force.

Production Units and Specifications

• SAW Steel Pipes: Produced in intermittent units with up to 15 procedures. They can be manufactured in various specifications, with thicknesses up to 80 mm.
• HF Steel Pipes: Produced in continuous assembly lines, typically resulting in thinner pipes with fewer specifications.

Distinguishing Between HF and SAW Steel Pipes

Appearance and Weld Characteristics

• HF Steel Pipes: Feature a smooth, level surface with no oxide coating. The weld is jagged and irregular, often requiring scraping before finalizing.
• SAW Steel Pipes: Have a slight indentation on the surface, with the weld typically higher than the parent metal by 1-3 mm. The weld may be ground down to meet customer specifications.

Standards and Certifications

Both HF and SAW steel pipes can adhere to the same standards, such as GB/T3091-2008, GB/T9711.1-2011, and API 5L PSL1/PSL2. However, their certifications differ:

• HF Steel Pipes: Certificates specify "ERW" (Electric Resistance Welding).
• SAW Steel Pipes: Certificates specify "ASWL" (Automatic Submerged Arc Welding).

Interesting Statistics

• Global Market Share: The global market for SAW pipes is projected to reach $7.2 billion by 2027, growing at a CAGR of 5.1% from 2020 to 2027 (source).
• Production Efficiency: SAW welding can achieve deposition rates of up to 45 kg/h, significantly higher than other welding methods (source).

Conclusion

Understanding the differences between submerged arc welding and high-frequency welding steel pipes is crucial for industry professionals. By recognizing their unique characteristics, production processes, and standards, one can make informed decisions regarding their applications and benefits. Whether for large-scale infrastructure projects or specialized industrial applications, both SAW and HF steel pipes offer distinct advantages that cater to various needs.

For more detailed information on welding techniques and standards, refer to authoritative sources such as the American Welding Society and the International Organization for Standardization.