Large Diameter Spiral Steel Pipe

Large Diameter Spiral Steel Pipe(also known as SSAW/SAWH pipe)is a high-strength,cost-effective steel pipe with a spiral weld seam,manufactured by cold-forming steel strips into a tubular shape and welding via double-sided submerged arc welding.It is widely used for large-scale fluid transmission and structural engineering due to its large diameter capability,excellent pressure resistance,and economic efficiency.

1.Manufacturing Process

Raw Material:Hot-rolled steel strips/coils(carbon steel,low-alloy steel,or pipeline steel like Q235B,Q355B,L245–L555).

Spiral Forming:The strip is continuously bent into a spiral tube blank at a constant angle,enabling the production of large diameters from narrow strips.

Welding:Double-sided automatic submerged arc welding(internal and external welds)ensures full penetration,fusion,and high weld quality.

Testing:Finished pipes undergo hydrostatic,bending,flattening,and non-destructive tests(X-ray/ultrasonic)to meet standards.

2.Key Specifications

Outer Diameter(OD):219 mm–4,064 mm(typically≥1,000 mm for"large diameter").

Wall Thickness(WT):3.2 mm–36 mm.

Length:6 m–12 m(custom lengths up to 20 m available).

Standards:API 5L(PSL1/PSL2),GB/T 9711,SY/T 5037,ASTM A252,EN 10217.

3.Core Advantages

High Strength&Pressure Resistance:Spiral welds distribute stress uniformly(60–85%of straight-seam pipe stress),allowing thinner walls for the same pressure and reducing weight.

Large Diameter Feasibility:Ideal for diameters>1 m;far more economical than seamless or straight-seam pipes for large sizes.

Cost-Effectiveness:Continuous coil-based production lowers material and manufacturing costs(20–40%cheaper than seamless pipes).

Durability&Corrosion Resistance:Can be coated with 3PE,epoxy coal tar pitch,or galvanized for long-term corrosion protection(service life up to 50+years).

Flexible Application:Suitable for both fluid transmission and structural support,adapting to complex terrains and long-distance projects.

4.Main Applications

Oil&Gas Transmission:Long-distance trunk pipelines(API 5L X42–X80)for crude oil,natural gas,and refined products.

Water Projects:Municipal water supply/drainage,seawater desalination,and agricultural irrigation pipelines.

Structural Engineering:Bridge piling,tunnel supports,high-rise building foundations,and large steel structures.

Industrial Piping:Power plants,chemical plants,and petrochemical facilities for high-pressure fluid transport.

5.Surface Treatment&Packaging

Treatment:Black paint,anti-corrosion coating(3PE/2PE),epoxy coating,or galvanization.

Packaging:Standard export packing(bundled with steel strips,plastic caps at ends)or as per customer requirements.