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Stainless Steel Seamless Pipes – Precision, Strength & Customization
Our 304 and 316L stainless steel seamless pipes are high-integrity tubular solutions engineered for distributors, engineering contractors, and equipment manufacturers in the oil, gas, chemical, and high-pressure industries. Manufactured from solid billets via hot extrusion or cold drawing, these seamless tubes eliminate weld seams to ensure uniform strength and density—making them the preferred choice for high-pressure boilers, heat exchangers, and corrosive fluid transport systems.
- Overview
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Key Features
· Zero Weld Seam Integrity – Manufactured from solid billets via rotary piercing; eliminates weak points to withstand hydrostatic pressures up to 20,000 psi in high-pressure boilers and hydraulic systems.
· Enhanced Corrosion Resistance – 316L grade contains 2–3% Molybdenum, offering 5x greater resistance to pitting and crevice corrosion in chloride-rich marine and chemical environments than standard 304.
· Precision Dimensional Accuracy – Cold-drawn process ensures tight OD/ID tolerances (±0.05mm) and a smooth internal surface (Ra ≤ 0.8μm), optimizing flow rates and minimizing pressure drop in fluid transfer lines.
· High-Temperature Stability – Maintains structural integrity and oxidation resistance in continuous service from -196°C up to 800°C, ideal for heat exchangers, exhaust manifolds, and cryogenic storage.
· Superior Ductility & Strength – Uniform grain structure provides excellent elongation properties (≥35%) while meeting ASTM A312 standards for both mechanical and pressure applications.
| Parameter | Details |
| Material Grade | ASTM A312 / A269 304 (18%Cr, 8%Ni) / 316L (2–3% Mo, C≤0.03%) |
| Manufacturing Method | Hot Extrusion (for large OD) & Cold Drawn (for high precision) |
| Outer Diameter (OD) | 6mm – 630mm (1/8" to 24") |
| Wall Thickness | 1.0mm – 40mm (Schedule 5S to XXS) |
| Length | Standard 6m; Fixed or random lengths available (Max 12m) |
| Surface Finish | Pickled & Annealed (AP), Bright Annealed (BA), Polished (180–600 grit), Mirror (8K) |
| Tolerance | OD: ±0.1mm (Cold Drawn) / ±0.5mm (Hot Finished); WT: ±10% |
| Testing | 100% Eddy Current Test; Hydrostatic Test (up to 20,000 psi); Ultrasonic Test (UT) available |
| Standards | ASTM A312, A213, A269; DIN 17456; GB/T 14976 (on request) |
| MOQ | 1 Ton (Mixed sizes accepted) |
| Lead Time | 10–20 working days (subject to size, wall thickness, and heat treatment) |
| Loading | 1×20GP ≈ 20–25 MT (approx. 2,000–4,000 pieces depending on OD/WT) |
Materials & Finish
· Base Metal (304 Grade): Austenitic stainless steel with 18% Chromium content; forms a dense, self-healing passive oxide layer that provides 10–15 years of maintenance-free service in atmospheric, fresh water, and mild industrial environments.
· Base Metal (316L Grade): Low-carbon steel fortified with 2–3% Molybdenum; specifically engineered to resist chlorides and reducing acids, extending service life to 20+ years even in aggressive coastal, marine, or chemical processing zones.
· Pickled & Annealed (AP) Finish: A dual-stage chemical treatment that removes scale and promotes chromium oxide reformation. This process ensures salt spray resistance ≥ 1,000 hours (ASTM B117) without red rust, restoring the metal's native corrosion barrier after extreme forming.
· Bright Annealed (BA) Finish: Heat-treated in a controlled, oxygen-free atmosphere to produce a highly reflective, smooth surface. This finish minimizes surface micropores, reducing the risk of bacterial adhesion and intergranular corrosion in high-purity applications.
· Mechanical Polishing (Ra ≤ 0.8μm): 180–600 grit or mirror (8K) finishes reduce surface roughness, preventing fluid entrapment and particle buildup. Ideal for hygienic systems, this ensures zero surface degradation and easy cleanability (CIP/SIP) over decades of use.
Applications
· Oil & Gas / Refinery Plants – High-pressure crude, natural gas and sour-gas lines (H₂S/Cl⁻ exposure); seamless body eliminates weld-leak risk at ≤20,000 psi and ≤800℃. Buyer: EPC contractors, refinery procurement, oilfield service companies. 
· Chemical & Acid Process Lines – Transfer of nitric/sulfuric/organic acids and chloride media; 316L Mo-content resists pitting where 304 fails above 200 ppm Cl⁻. Buyer: Chemical equipment OEM, acid plant engineers.
· Boilers & Heat Exchangers – Superheater, reheater and condenser tubes in power stations; uniform cold-drawn wall handles thermal cycling from -196℃ to 800℃ without seam fatigue. Buyer: Boiler makers, thermal/nuclear power MRO.
· Marine & Offshore Structures – Seawater cooling, desalination RO feed, ship ballast and offshore wind foundation piles; 316L service life 20+ yrs in coastal salt-spray vs 304’s 10–15 yrs inland. Buyer: Shipyards, marine engineering, desalination EPCs. 
· Pharma / Food / Biotech Hygiene Lines – WFI, pure steam, CIP return and dairy/brewery fill lines; mirror (8K) or electropolished ID Ra≤0.8μm meets ASME BPE / GMP, no bacteria harbor. Buyer: Pharma machinery OEM, dairy/beverage bottlers. 
· Semiconductor & High-Purity Gas – Small-bore 316L seamless capillary for UHP N₂/O₂/Ar and wet-bench chemical delivery; zero weld inclusion avoids particle shedding. Buyer: Semiconductor fabs, lab gas system integrators. 
· Medical Devices & Instruments – Surgical instrument shafts, dialysis fluid paths, imaging equipment frames; 316L biocompatible, passivated, salt-spray ≥1000 h no red rust. Buyer: Medical device manufacturers, hospital engineering. 
· Hydraulic & Precision Machinery – Cylinder barrels, pneumatic rods, CNC machine coolant lines; cold-drawn OD tolerance ±0.05mm gives straight, fatigue-resistant bore. Buyer: Hydraulic cylinder factories, automation machine builders.
| Option | Details |
| Dimensions (OD & Wall Thickness) | Outer Diameter from 6mm to 630mm; Wall Thickness from 1.0mm to 40mm. Custom non-standard sizes and heavy wall (XXS) available upon request. |
| Length & Cutting | Standard 6m length; custom precision cutting to fixed lengths (max 12m) or short pieces (min 50mm) to minimize waste and machining time on site. |
| Surface Finish | Pickled & Annealed (AP), Bright Annealed (BA), Mechanical Polish (180–600 grit), Mirror (8K), or Electropolished (EP) for high-purity applications. |
| Heat Treatment | Solution annealing, stress relieving, or quenching and tempering to meet specific mechanical properties (Tensile/Yield strength). |
| Marking & Branding | OEM service available: Laser printing, electrochemical etching, or stencil spray for logos, heat numbers, and specification codes on pipes. |
| Packaging | Standard: Woven bag/nylon sleeve Premium: Individual cardboard sleeves, plywood crates, or pallets for high-grade finishes or export protection. |
| MOQ | 1 Ton (Mixed sizes, wall thicknesses, and finishes accepted for bulk orders). |
