Spiral Welded Steel Pipe

Spiral Submerged Arc Welded Pipe,also known as Double Submerged Arc Welded(DSAW)Spiral Pipe or Double-Sided Submerged Arc Welded Spiral Pipe,is a high-performance welded steel pipe specifically designed for high-pressure,large-scale industrial and infrastructure projects.It is manufactured by cold-forming hot-rolled steel coils into a spiral tubular blank,followed by simultaneous or sequential double-sided submerged arc welding(internal and external welds),ensuring full weld penetration,uniform fusion,and superior structural integrity.

1.Core Manufacturing Process

The production of DSAW spiral pipe adheres to strict industrial standards,with key steps ensuring consistency and quality:

-Raw Material Selection:High-quality carbon steel,low-alloy steel,or pipeline steel coils(e.g.,Q235B,Q355B,API 5L X42-X80,L245-L555)are adopted,with strict inspection of chemical composition and mechanical properties to meet project requirements.

-Spiral Forming:The steel coil is continuously bent into a spiral shape at a fixed helix angle by a professional forming machine,which allows the production of large-diameter pipes using narrow steel strips,realizing cost optimization and size flexibility.

-Double-Sided Submerged Arc Welding:The most critical process—automatic submerged arc welding is applied to both the inner and outer surfaces of the spiral seam.The submerged arc welding method isolates the weld from air,reducing defects such as porosity,cracks,and incomplete fusion,while ensuring the weld seam has high strength,toughness,and pressure-bearing capacity.

-Quality Inspection:Finished pipes undergo rigorous testing,including hydrostatic pressure testing(to verify pressure resistance),non-destructive testing(X-ray,ultrasonic,or magnetic particle testing to detect internal and surface defects),bending,flattening,and tensile tests,ensuring compliance with international and national standards.

2.Key Specifications&Standards

-Outer Diameter(OD):219mm-4064mm,with large-diameter options(≥1000mm)being the core advantage,suitable for large-flow transmission projects.

-Wall Thickness(WT):3.2mm-36mm,customizable according to pressure and load requirements.

-Length:Standard length 6m-12m,custom lengths up to 20m available for specific engineering needs.

-Applicable Standards:API 5L(PSL1/PSL2),GB/T 9711,SY/T 5037,ASTM A252,EN 10217,ensuring compatibility with global engineering projects.

3.Core Advantages

-Superior Weld Quality:Double-sided submerged arc welding eliminates weld defects,making the weld seam as strong as the pipe body,with excellent impact toughness and fatigue resistance,suitable for long-term operation under harsh conditions.

-Strong Pressure Bearing Capacity:The spiral seam distributes stress evenly(60%-85%of the stress of straight-seam pipes),enabling the pipe to withstand high internal pressure and external load,reducing the risk of leakage and deformation.

-Cost-Effectiveness:Compared with seamless pipes and straight-seam DSAW pipes,spiral DSAW pipes use continuous coil production,reducing material waste and manufacturing costs,especially for large-diameter specifications(20%-40%cost savings).

-Durability&Corrosion Resistance:Can be processed with various anti-corrosion treatments,such as 3PE/2PE coating,epoxy resin coating,coal tar pitch coating,or galvanization,extending the service life to 50+years in complex environments(e.g.,underground,coastal,or chemical fields).

-Size Flexibility:Flexible adjustment of diameter,wall thickness,and length according to project needs,adapting to different engineering scenarios without excessive customization costs.