Spiral steel pipes are made from coiled strip steel, formed through cold extrusion and welded using the submerged arc welding process. The strip steel is fed into the welding unit, rolled by multiple rollers, and gradually coiled into a circular pipe blank with an open seam. The gap between the weld seams is controlled at 1–3 mm by adjusting the pressure of the squeeze rollers, ensuring flush alignment at both ends of the weld.
Spiral steel pipes can be manufactured with single-sided welding or double-sided welding. The welded pipes must meet the following standards:
Hydrostatic Pressure Test – Ensures leak-proof performance under specified pressure.
Weld Tensile Strength – The joint must achieve the required mechanical strength.
Cold Bend Performance – The weld zone should withstand bending without cracking.
Classification:
By Material: Stainless steel, carbon steel, low-alloy steel, alloy steel, etc.
By Process: Double-sided submerged arc welding, single-sided submerged arc welding.
By Application:
Fluid transportation (e.g., water, oil, gas).
Piling pipes (e.g., construction foundations).
By Pressure Resistance:
Low-pressure fluid pipelines.
Standard pressure-resistant pipelines.
By Manufacturing Standards:
National (GB), American (API/ANSI), Japanese (JIS), Russian (GOST), etc.
Characteristics:
High corrosion resistance and plasticity.
Higher strength compared to straight-seam welded pipes.
Enables production of large-diameter pipes from narrow strip steel.
Flexible pipe diameter output using the same raw material width.
Applications:
Domestic: Water supply, drainage, urban construction.
Industrial: Petroleum, chemical, power, agricultural irrigation.
Gas Transport: Natural gas, steam, LPG.
Structural Use: Piling, bridges, docks, roads, and architectural frameworks.
