1. Product specifications of API5L straight seam steel pipe:
Diameter of API5L straight seam steel pipe: Ф406.4～Ф1422.4mm (16-56in)
Length of API5L straight seam steel pipe: 3～12.5m
The wall thickness of API5L straight seam steel pipe: The production range of ordinary carbon and low carbon alloy materials is 8～50mm; the wall thickness of medium carbon alloy structural steel with steel grade above X70 can reach 6.4-26.4mm (0.252–1.04in)
Product standards of API5L straight seam steel pipe: SO3183, API Spec 5LI, API Spec 2B, GB/T9711 and other standards
Production of API5L straight seam steel pipe: Annual production of 150,000 tons of large-diameter straight seam submerged arc welded steel pipes
Material composition and mechanical properties of API5L straight seam steel pipe:
Chemical composition: Taking L245 (X42) as an example, carbon (C) ≤ 0.26%, manganese (Mn) ≤ 1.20%, niobium (Nb), vanadium (V), titanium (Ti) total ≤ 0.15%6.
Mechanical properties: yield strength ≥ 245MPa (L245), tensile strength ≥ 415MPa, high steel grade such as X70 (L485) yield strength can reach 485MPa, tensile strength 570MPa6.
Implementation standards of API5L straight seam steel pipe:
Complying with API SPEC 5L, GB/T9711.1, ISO3183, and other standards, some products have passed PSL2 (enhanced performance level) certification.
2. Application of API5L straight seam steel pipe:
Mainly used for the transportation of medium such as land and marine oil and gas, coal slurry, and ore slurry, as well as pipes for offshore platforms, power stations, chemical industry, and urban building structures.
●.After the overall mechanical expansion treatment, the internal stress of the steel pipe is small and evenly distributed, which can effectively prevent stress corrosion cracking, with high dimensional accuracy and convenience for on-site welding construction.
●The process of pre-welding and then fine welding is adopted, the welding process is stable and the weld quality is high.
●The weld is easy to achieve non-destructive testing during the production process and non-destructive testing review in the field during use.
●.Compared with non-straight welded steel pipes, the weld is short and the probability of welding defects is small.
●The product specification range is large, and both small-diameter and large wall-thickness steel pipes can be produced.
3. Production process and technological innovation of API5L straight seam steel pipe
Forming process
JCOE forming: The tube blank is formed by multi-step progressive stamping, which is suitable for large-diameter steel pipes (such as Φ1420mm), with high accuracy and uniform stress distribution.
High-frequency resistance welding (HFW) and submerged arc welding (SAW): HFW is suitable for small and medium-sized diameters and has a fast welding speed; SAW is used for large-diameter pipelines, with a large weld depth and stable quality.
Post-processing technology
Mechanical expansion: eliminate internal stress and improve dimensional accuracy (ovality <0.17%).
Heat treatment: quenching and tempering (quenching + tempering) optimizes microstructure and improves fatigue resistance.
4. API5L straight seam steel pipe quality control and inspection technology
Non-destructive testing (NDT)
Ultrasonic testing (UT): used for weld and heat-affected zone defect detection, can identify defects such as inclusions and cracks, with a sensitivity of φ1.6mm through-hole reflection wave. Radiographic testing (RT): Re-inspect the 200mm range of the pipe end to ensure that there are no unfused pores in the weld.
Geometric accuracy and tolerance
Diameter tolerance: ±0.0075D (D＞168.3mm), out-of-roundness ≤0.02D.
Wall thickness deviation: ±0.1t (t≤15mm), maximum straightness deviation ≤0.2%L.
Hydraulic pressure test
Test pressure formula:
P=2St/D. Where S is the hoop stress (usually 60-90% of the yield strength), ensuring that the pipeline is leak-free under high pressure.
5. Anti-corrosion treatment of API5L straight seam steel pipe
Common anti-corrosion methods include enhanced 3PE anti-corrosion, which consists of a bottom epoxy powder coating, an intermediate hot melt adhesive layer, and a top high-density polyethylene layer. The epoxy powder coating has excellent chemical corrosion resistance and anti-cathodic stripping performance. The hot melt adhesive layer enhances the bonding between the layers, and the high-density polyethylene layer provides physical protection, which can effectively resist the erosion of various corrosive media such as acid, alkali, and salt water, and extend the service life of the steel pipe.
6. Uses and application areas of API5L straight seam steel pipe
It is widely used in long-distance transmission pipelines in industries such as petroleum, natural gas, chemical industry, and electric power, as well as urban pipe network construction such as urban gas and urban water supply. It can also be used as pile foundation pipes, bridge pipes, building structure pipes, etc. Its good corrosion resistance and mechanical properties enable it to maintain a good operating state in harsh working conditions such as ocean, chemical industry, and petroleum.
Post time: May-14-2025