1. API5L straight seam steel pipe product specifications:
API5L straight seam steel pipe diameter: Ø 406.4 to Ø 1422.4mm (16-56 inches)
API5L straight seam steel pipe length: 3-12.5m
API5L straight seam steel pipe wall thickness: Production range of ordinary carbon steel and low-carbon alloy steel: 8-50mm; wall thickness of X70 and above grade medium carbon alloy structural steel can reach 6.4-26.4 millimeters (0.252-1.04 inches).
API5L straight seam steel pipe product standards: SO3183, API Spec 5LI, API Spec 2B, GB/T9711 and other standards.
API5L straight seam steel pipe production capacity: Annual production of 150000 tons of large-diameter straight seam submerged arc welded steel pipes.
Composition and mechanical properties of API5L straight seam steel pipe material:
Chemical composition: Taking L245 (X42) as an example, carbon (C) ≤ 0.26%, manganese (Mn) ≤ 1.20%, and the total content of niobium (Nb), vanadium (V), and titanium (Ti) ≤ 0.15%.
Mechanical properties: Yield strength ≥ 245MPa (L245), tensile strength ≥ 415MPa. High steel grades such as X70 (L485) can achieve a yield strength of 485MPa and a tensile strength of 570MPa.
API5L straight seam steel pipe execution standard:
Compliant 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 onshore and offshore oil and gas, coal slurry, ore slurry and other media, as well as pipelines for offshore platforms, power stations, chemical industries, urban building structures, etc.
●. 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 convenient on-site welding construction.
Adopting pre welding and precision welding technology, the welding process is stable and the weld quality is high.
The weld seam is easy to undergo non-destructive testing during the production process and easy to perform on-site non-destructive testing review during use.
Compared with non straight seam steel pipes, the weld seam is shorter and the probability of welding defects is lower.
The product specification range is wide, and both small caliber and large wall thickness steel pipes can be produced.
3. Production process and technological innovation of API5L straight seam steel pipe
Molding Process
JCOE Forming: The tube blank is formed by multi station progressive stamping, suitable for large-diameter steel pipes (such as Φ 1420mm), with high precision 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 fast welding speed; Large diameter pipelines use submerged arc welding (SAW), with a deep weld seam and stable quality.
Post processing technology
Mechanical diameter expansion: eliminates internal stress and improves dimensional accuracy (ellipticity<0.17%).
Heat treatment: quenching+tempering (quenching+tempering) optimizes the microstructure and improves fatigue resistance.
4. Quality Control and Testing Technology for API5L Straight Seam Steel Pipe
Non destructive testing (NDT)
Ultrasonic Testing (UT): Used for defect detection in welds and heat affected zones, it can identify defects such as inclusions and cracks, with a sensitivity of reflected waves from a 1.6mm through-hole. Radiographic testing (RT): Conduct a re inspection within 200mm of the pipe end to ensure that there are no incomplete fusion pores in the weld seam.
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.
Hydrostatic test
Test pressure formula:
P=2St/D。 Among them, S is the circumferential stress (usually 60-90% of the yield strength), ensuring that the pipeline has no leakage 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 layer of epoxy powder coating, a middle hot melt adhesive layer, and a top layer of high-density polyethylene. Epoxy powder coating has excellent chemical corrosion resistance and cathodic stripping resistance. The hot melt adhesive layer enhances the interlayer bonding force, and the high-density polyethylene layer provides physical protection, which can effectively resist the erosion of various corrosive media such as acid, alkali, salt water, etc., extending the service life of the steel pipe.
6. Application and fields of API5L straight seam steel pipe
Widely used in long-distance transmission pipelines in industries such as oil, natural gas, chemical, and electricity, as well as urban gas and water supply network construction. It can also be used as pile foundation pipe, bridge pipe, building structure pipe, etc. Its excellent corrosion resistance and mechanical properties enable it to maintain good operating conditions in harsh working conditions such as marine, chemical, and petroleum industries.
