What are the differences between spiral welded pipes and ordinary welded pipes

The core differences between spiral welded pipes and ordinary welded pipes (usually referring to straight seam welded pipes) lie in the ‌ welding process, applicable range of pipe diameters, strength performance and application scenarios ‌. The weld seam of the spiral welded pipe is in a spiral shape, which is suitable for large-diameter high-pressure transportation. The weld seam of straight seam welded pipes is straight, making them suitable for medium and small diameter low-pressure scenarios. ‌ ‌ ‌ ‌

Differences in production processes and structures

Spiral welded pipes are made by rolling steel strips into pipe blanks at a spiral Angle and then welding them. The weld seam length is 30% to 100% longer than that of straight seam welded pipes, but the spiral weld seam makes the stress distribution more uniform. Straight seam welded pipes are made by directly bending steel plates or steel strips into a straight weld seam. The process is simple, but residual stress is prone to occur at the weld seam, which may increase the risk of cracking. ‌ ‌ ‌ ‌

Pipe diameter range and strength performance

Youdaoplaceholder0 Pipe diameter applicability ‌ : The commonly used nominal diameter of spiral welded pipes is DN200 (8 inches) and above, and large-diameter pipes can be produced with narrower billets. Straight seam welded pipes are suitable for medium and small diameters ranging from DN15 (4 inches) to DN150 (6 inches). ‌ ‌ ‌ ‌

Youdaoplaceholder0 Strength comparison ‌ : Spiral welded pipes have a higher compressive strength due to the dispersed stress in the spiral weld seam, making them particularly suitable for high-pressure fluid transportation. Straight seam welded pipes have a relatively weak pressure-bearing capacity under the same wall thickness, but they have high production efficiency and low cost. ‌ ‌

Application scenarios and selection basis

Youdaoplaceholder0 spiral welded pipe ‌ : mainly used in long-distance oil and gas pipelines, Marine engineering and high-pressure fluid transportation, it needs to withstand relatively high internal pressure. ‌ ‌

Youdaoplaceholder0 straight seam welded pipe ‌ : Widely used in fields such as building structures, low-pressure fluid transportation (such as water and gas), urban pipe networks, etc., where cost is sensitive and pressure requirements are not high. ‌ ‌ ‌ ‌

When making a selection, the pipe diameter, pressure requirement and cost should be comprehensively considered: spiral welded pipes are preferred for large-diameter high-pressure scenarios, while straight seam welded pipes are more economical for medium and small-diameter low-pressure scenarios. ‌ ‌