316L large diameter stainless steel welded pipe is an ultra-low carbon molybdenum-containing austenitic stainless steel tubular product. It is manufactured by advanced roll forming and longitudinal welding process, featuring large caliber, smooth weld seam, stable dimension and excellent overall performance. Compared with seamless pipes, large-diameter welded pipes have lower cost, higher delivery efficiency and more flexible large-size customization. The addition of molybdenum element provides outstanding resistance to chloride, seawater and acidic medium corrosion, making it widely applicable for harsh industrial environments.
2. Chemical Composition (ASTM A312 / UNS S31603, Weight %)
Strictly controlled ultra-low carbon design avoids intergranular corrosion after welding, suitable for long-term welded structure service.
Carbon (C): ≤ 0.03% (Ultra-low carbon)
Silicon (Si): ≤ 1.00%
Manganese (Mn): ≤ 2.00%
Phosphorus (P): ≤ 0.045%
Sulfur (S): ≤ 0.030%
Chromium (Cr): 16.00 – 18.00%
Nickel (Ni): 10.00 – 14.00%
Molybdenum (Mo): 2.00 – 3.00%
Nitrogen (N): ≤ 0.10%
Iron (Fe): Balance
3. International Equivalent Grades (Cross-Country Standard Matching)
Fully compatible with global mainstream standards, convenient for international project bidding and customer acceptance.
USA Standard: ASTM A312 TP316L / UNS S31603
European Standard: EN 1.4404 / X2CrNiMo17-12-2
Chinese Standard: GB 022Cr17Ni12Mo2
Japanese Standard: JIS SUS316L
German Standard: DIN 1.4404
ISO Standard: ISO X2CrNiMo17122
4. Physical & Mechanical Properties (Annealed State, Standard Reference)
– Density: 7.98 g/cm³
– Melting Temperature Range: 1375 – 1400°C
– Elongation: ≥ 35%
– Hardness: ≤ 201 HB / ≤ 90 HRB
Performance Features: Excellent toughness, stable mechanical performance at low and high temperatures, no cracking during bending, flaring and welding.
5. Production Standard & Product Specifications
5.1 Executive Standards
ASTM A312, ASTM A358, EN 10217-7, GB/T 12771, JIS G3459
5.2 Size Range
– Outer Diameter: 114mm – 2000mm (Large-diameter customized)
– Wall Thickness: 2.0mm – 20mm
– Length: 6m / 12m fixed length or customized
– Tolerance: Strict OD & wall thickness tolerance, flat pipe end, uniform roundness
6. Surface Treatment & Quality Control
6.1 Common Surface Finishes
– Pickled Matte Surface: Standard industrial surface, no oxide scale, acid-cleaned, suitable for general chemical and pipeline projects.
– Polished Bright Surface: Fine internal and external polishing, smooth finish, for decorative and sanitary pipeline systems.
– Annealed Clean Surface: Stress-relieved by bright annealing, clean inner wall, no residue, for high-purity fluid delivery.
6.2 Testing & Inspection
100% weld seam ultrasonic testing, hydraulic pressure test, eddy current inspection, chemical composition spectroscopic analysis and dimensional precision inspection to ensure zero defect delivery.
7. Core Product Advantages
– Superior Corrosion Resistance: Molybdenum alloying element resists chloride corrosion, seawater erosion, acid and alkali medium, far better than 304/304L.
– Excellent Weldability: Ultra-low carbon structure effectively prevents welding intergranular corrosion, no need for post-weld heat treatment.
– High Cost Performance: Large-diameter size is more cost-effective than seamless pipe with stable performance and short production cycle.
– Stable Structure: After solid solution annealing, internal stress is eliminated, no deformation during processing and long-term service.
– High Hygiene & Safety: Non-toxic, no precipitation, compliant with industrial and sanitary safety standards.
8. Main Applications
– Chemical & Petrochemical Industry: Acid-base fluid pipelines, reaction vessel piping, chemical sewage delivery pipes.
– Marine & Offshore Engineering: Seawater desalination pipelines, offshore platform piping, salt-fog corrosion resistant structures.
– Water Treatment & Environmental Protection: Urban water supply and drainage, pure water engineering, sewage treatment equipment pipelines.
– Food & Pharmaceutical Industry: Large-diameter sanitary conveying pipelines, beverage and pharmaceutical production systems.
– Power & Thermal Engineering: Heat exchanger pipes, high-temperature and high-pressure industrial piping systems.
– Construction & Municipal Engineering: Large-diameter structural pipes, corrosion-resistant building piping, landscape engineering pipelines.
9.Export Packaging
Pipe ends protected by plastic caps, pipe surface wrapped with waterproof PVC film and woven belt, fixed with steel strips, moisture-proof and shockproof, suitable for long-distance ocean transportation.
