Seamless steel pipe and spiral steel pipe are two distinct categories of steel piping, differing in manufacturing methods, structural features, performance, and applications. Continental Steel Co., Ltd. summarizes the four main differences as follows:
- Manufacturing Process
Seamless Steel Pipe
Principle: Produced from solid billets through piercing, rolling, cold drawing, or cold rolling, forming a continuous pipe without welds.
Features: Dense, uniform structure with no weld-related stress points.
Spiral Steel Pipe
Principle: Manufactured from steel strip coils, formed into a circular shape using a spiral forming machine, followed by double-sided submerged arc welding along the spiral seam.
Features: Contains one or more spiral welds, each several times longer than the pipe length.
- Structure & Appearance
Seamless steel pipe: Smooth surface, straight tube body, no weld marks.
Spiral steel pipe: Visible spiral weld seams on both inner and outer surfaces.
- Performance & Applications
Seamless Steel Pipe
Strength & Pressure Resistance: High integrity and durability; suitable for high-pressure, high-temperature, and high-strength applications.
Typical Uses: High-pressure boiler lines, main oil and gas pipelines, hydraulic systems, chemical pipelines.
Size Range: Limited by production technology; generally smaller diameters with controlled wall thickness ranges.
Spiral Steel Pipe
Strength & Pressure Resistance: Weld is the structural weak point; double-sided welding improves strength but cannot match seamless pipe performance. Excellent for large diameters under lower pressures.
Typical Uses: Water supply lines, heating pipelines, large-scale water projects, low-pressure oil and gas pipelines, piling, and structural supports.
Size Range: Very wide diameter capability, including large and ultra-large sizes.
- Cost
Seamless steel pipe: Higher production complexity and raw material quality requirements result in higher costs—especially for large diameters.
Spiral steel pipe: More economical due to simpler, coil-based production; cost advantage is significant for large-diameter pipes.
Summary & Selection Guide
Choose seamless steel pipe for projects requiring high safety, high pressure, and high strength—such as petrochemical and power boiler systems.
Choose spiral steel pipe for large-diameter, cost-sensitive projects—such as municipal water systems and structural supports.
Ultimately, selection depends on operating pressure, required diameter, and budget.
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