Introduction to X52NS Hydrogen Sulfide-Resistant Large Diameter LSAW Steel Pipe

X52NS Hydrogen Sulfide-Resistant Large Diameter LSAW Steel Pipe is designed specifically for oil and gas transmission in hydrogen sulfide (H₂S) environments. Its performance specifications strictly comply with API 5L standards. Combined with anti-sulfur treatment, it has become a core equipment for the development of highly corrosive oil and gas fields.

X52NS steel pipe achieves significantly improved resistance to hydrogen sulfide corrosion through composition optimization and heat treatment. Its sulfur and phosphorus contents are controlled to ≤0.008% and ≤0.015%, respectively, and a trace amount of copper (Cu ≤0.35%) is added to inhibit hydrogen-induced cracking (HIC). Normalizing (heating at 920°C followed by cooling at 2-5°C/s) refines the microstructure to a ferrite + pearlite structure with a grain size of 8.5 or higher, effectively reducing the hydrogen diffusion rate. NACEMR0175 standard testing shows that this steel pipe achieves 100% compliance with HIC resistance and a crack sensitivity rate (CSR) of ≤0.5% in extreme environments with an H₂S partial pressure ≥0.1 MPa and a pH ≤4, meeting the transportation requirements of high-sulfur oil and gas fields in the Middle East, Sichuan, and Chongqing.

Large-diameter straight seam submerged arc welded steel pipe utilizes the JCOE or UOE forming process, combined with twin-wire submerged arc welding technology to achieve a balance between weld quality and production efficiency. Using the JCOE process as an example, after pre-bending, J-forming, and O-joining the steel plates, twin-wire submerged arc welding is used for internal and external weld filling. Weld penetration reaches over 80% of the plate thickness, ensuring that the weld joint strength matches that of the base material. Post-weld testing, online ultrasonic flaw detection (UT), and X-ray testing (RT) can detect internal defects larger than 0.5 mm, with a defect detection rate of ≥99.5%.

X52NS steel pipe has been widely used in key national projects such as the West-East Gas Pipeline III and the Central Asia Natural Gas Pipeline, as well as in the gathering and transportation system of high-sulfur gas wells in a Middle Eastern oil field. In marine engineering, its synergistic performance in seawater corrosion resistance and sulfur resistance makes it the preferred material for submarine pipelines.

Modern X52NS steel pipe production incorporates digital coil management technology, enabling full lifecycle traceability from production to construction via RFID chips. Furthermore, the application of the hydrogen-based direct reduced iron (DRI) + electric arc furnace process reduces carbon emissions by 30% compared to traditional processes, driving the transition to low-carbon oil and gas equipment manufacturing.

X52NS hydrogen sulfide-resistant large-diameter longitudinal submerged arc welded steel pipe, with its excellent corrosion resistance, sophisticated manufacturing process, and wide application adaptability, has become a "golden material" for global energy infrastructure construction, providing a solid foundation for the safe development of highly corrosive oil and gas resources.