316L stainless steel pipe is a low-carbon austenitic stainless steel pipe, the low-carbon variant of 316 stainless steel (UNS S31603, equivalent to SUS316L in Japan, 1.4404 in Europe, and 022Cr17Ni12Mo2 in China). It is characterized by ultra-low carbon content (≤0.035%), supplemented with 2.0–3.0% molybdenum, which endows it with superior corrosion resistance, especially in chloride-rich environments. It is widely recognized as a “marine-grade” stainless steel pipe and is extensively used in industries with high corrosion resistance requirements.
Key Characteristics
- Excellent Corrosion Resistance: Molybdenum addition significantly improves resistance to pitting corrosion, crevice corrosion, and stress corrosion cracking (SCC) in seawater, brine, and other chloride-containing media.
- Outstanding Intergranular Corrosion Resistance: Ultra-low carbon content effectively inhibits chromium carbide precipitation at grain boundaries during welding and high-temperature service, eliminating sensitization and ensuring corrosion stability of welded joints.
- Superior Weldability: Low carbon reduces weld decay risk; it can be welded by common methods (TIG, MIG, submerged arc welding) without post-weld heat treatment.
- Good Mechanical Properties: Maintains moderate tensile and yield strength at room and elevated temperatures, with excellent ductility and formability.
- Non-magnetic: Typically non-magnetic in the annealed state; slight magnetism may appear after cold working.
- Heat Resistance: Exhibits good oxidation resistance and creep strength at high temperatures (up to ~870°C).
Production & Types
- Manufacturing Processes: Seamless pipes via hot rolling, cold rolling, and cold drawing; welded pipes via ERW (electric resistance welding), LSAW (longitudinal submerged arc welding), etc.
- Product Forms: Seamless pipes, welded pipes, heavy cold-worked pipes; available with plain ends, beveled ends, or threaded ends.
- Surface Treatments: Pickling, passivation, bright annealing, mechanical polishing (Ra ≤ 0.8μm for hygienic applications).
Chemical Composition (wt%, ASTM A312/ASME SA312)
| Element |
316L (S31603) |
316 (S31600, for comparison) |
| Carbon (C) |
≤0.035 |
≤0.08 |
| Manganese (Mn) |
≤2.00 |
≤2.00 |
| Silicon (Si) |
≤1.00 |
≤1.00 |
| Phosphorus (P) |
≤0.045 |
≤0.045 |
| Sulfur (S) |
≤0.030 |
≤0.030 |
| Chromium (Cr) |
16.0–18.0 |
16.0–18.0 |
| Nickel (Ni) |
10.0–14.0 |
10.0–14.0 |
| Molybdenum (Mo) |
2.0–3.0 |
2.0–3.0 |
| Nitrogen (N) |
≤0.10 |
≤0.10 |
| Iron (Fe) |
Balance |
Balance |
Dimensional Specifications & Tolerances
| Parameter |
Seamless Pipes |
Welded Pipes |
Tolerance |
| Outer Diameter (OD) |
Φ3–Φ600mm |
Φ6–Φ1219mm |
±1% (ISO 10216) or ±0.13mm |
| Wall Thickness |
0.5–50mm |
0.3–45mm |
±10% of nominal thickness |
| लंबाई |
4–12m (fixed length) |
≤18m |
Customizable |
| Ovality |
– |
– |
≤1% of nominal OD |
| Straightness |
– |
– |
3.2mm per 1.5m length |
Mechanical Properties (Room Temperature, ASTM A312)
| Property |
316L (S31603) |
316 (S31600) |
Unit |
| Tensile Strength (min) |
485 |
515 |
MPa (70 ksi / 75 ksi) |
| Yield Strength (0.2% offset, min) |
170 |
205 |
MPa (25 ksi / 30 ksi) |
| Elongation (in 50mm, min) |
35 |
35 |
% |
| Hardness (max) |
95 HRB / 217 HBW |
95 HRB / 217 HBW |
– |
Applicable Standards
- International: ASTM A213, A269, A312, A632; ASME SA213, SA312
- European: EN 10216-5
- Japanese: JIS G3459
- Chinese: GB/T 14976, GB/T 20878
Typical Applications
- Petrochemical & Chemical Industry: Pipelines for corrosive media (sulfuric acid, hydrochloric acid, brine), reactors, heat exchangers, and storage tanks.
- Marine & Offshore Engineering: Seawater pipelines, desalination equipment, offshore platform piping (resists seawater corrosion).
- Food & Pharmaceutical Industry: Hygienic pipelines for food processing, beverage production, and pharmaceutical manufacturing (non-toxic, easy to clean, meets sanitary standards).
- Medical Devices: Surgical instruments, implant components, and medical equipment piping (biocompatible, corrosion-resistant).
- Water Treatment: Desalination plants, wastewater treatment pipelines, and high-purity water systems.
- Construction & Decoration: Coastal building handrails, curtain wall frameworks, and decorative piping (resists salt spray corrosion).
