ST52 Seamless Steel Pipe

ST52 seamless steel pipe is a high-strength low-alloy seamless pipe under DIN standard, equivalent to E355 grade. Our mill can produce to ASTM A106, ASTM A53 and ASTM A519 specifications to meet global export projects including oil & gas transmission, well-site piping, heavy machinery and steel structures. Manufactured by hot piercing of solid billet or cold finishing, the pipe has zero weld seam, widely trusted by international contractors for high-pressure fluid transportation.

Chemical Composition (Max. wt%) C ≤0.22%, Si ≤0.55%, Mn ≤1.60%, P ≤0.035%, S ≤0.040%. Tight impurity control ensures excellent weldability for site welding.

Mechanical Properties Minimum yield strength ≥355 MPa, tensile strength 490–630 MPa, elongation ≥22%, hardness approx.160–180 HB. Stable low-temperature toughness, resistant to deformation and cracking under heavy load and cyclic pressure.

Monolithic seamless construction for safer oil transport No welding seam, uniform pressure distribution and zero risk of weld corrosion, crack or leakage. Smooth inner and outer surface reduces friction loss for crude oil, refined oil and gas mixture. Honing service is available to achieve H7/H8/H9 precision tolerance for hydraulic cylinder tubing.

Dual-standard supply for international projects Base grade DIN ST52, available with ASTM conversion. Full SCH schedule including Sch40, Sch80, Sch160. Pipe ends can be customized as plain end, beveled end or threaded end for easy connection with flanges, elbows and tees.

Multiple anti-corrosion options for harsh oilfield environments For buried pipeline, saline and desert oilfield service, we offer 3PE,3PP,FBE epoxy coating, coal tar epoxy coating. Other surface options: sand blasting, black finish, anti-rust oil, hot-dip galvanizing to extend service life onshore and offshore.

Full inspection & complete export documentation Each batch undergoes PMI chemical analysis, tensile & impact test, hydrostatic test, plus NDT inspection: UT, MT, ET. Mill Test Certificate (MTC) provided. Third-party inspection SGS/BV is acceptable, satisfying petroleum project acceptance and customs clearance.

Wide size range & flexible delivery OD:10mm–630mm; Wall thickness:2mm–100mm. Random length or fixed cut length (6m,9m,12m). Small & bulk orders welcome, invoicing by theoretical or actual weight. Bundled with anti-rust protection for ocean shipment.

✅ Crude oil, refined oil, oil-gas-water multiphase transmission pipelines

✅ Oilfield well site piping, derrick structure, gathering station process piping

✅ Petroleum machinery, drilling rig parts, hydraulic lines, cylinder tube blanks

✅ Steel structures, bridge supports, pressure vessels, medium & high pressure piping

✅ Mining equipment, construction machinery chassis, heavy agricultural frames

✅ Low-temperature energy projects & municipal pressure pipelines

Samples available for material testing; on-site third-party supervision acceptable. Marking & painting as requested. Shipment from nearby ports, FOB / CFR / CIF trade terms supported.

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