SS 316 Flanges
Stainless steel 316 flanges are essential piping components valued for their superior corrosion resistance, higher strength, and excellent formability. As an SS316 flanges manufacturer and exporter, we guarantee our flanges conform to international standards, come in various face types and pressure ratings, and are backed by comprehensive testing and material traceability. We supply stainless steel 316 flanges to global customers in petrochemical, food & beverage, pharmaceutical, water treatment, power generation, and general industrial sectors.
Why SS 316 Flanges?
- Corrosion resistance: Good resistance to atmospheric corrosion and many chemical environments due to high chromium and nickel content.
- Versatility: Suitable for welded and threaded connections; available in many types (slip-on, welding neck, blind, lap joint, socket weld, threaded).
- Fabrication-friendly: Excellent formability and weldability for domestic and custom configurations.
- Cost-effective: Less expensive than higher-alloy stainless steels (e.g., 316) while offering robust performance in many applications.
Standards & Material Specifications
- Primary material: Stainless Steel 316 (UNS S31600).
- Related variants: SS 316L (low carbon version, UNS S31603) for improved resistance to sensitization during welding.
- Common flange material spec: ASTM A182 F316 (for forged or rolled flanges) and ASTM A240 (for plate/sheet material used in flange manufacture).
- Typical standards for flange dimensions and pressure classes: ASME B16.5 (for sizes NPS 1/2″–24″), ASME B16.47 (large diameter), EN 1092 (European), and JIS where applicable.
Product Range
- Types: Welding Neck, Slip-On, Blind, Socket Weld, Threaded, Lap Joint.
- Face styles: Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ).
- Pressure classes: 150#, 300#, 600#, 900#, 1500#, 2500# (per ASME B16.5).
- Sizes: 1/2″ up to 24″ (B16.5) and larger per B16.47/EN 1092.
- Finish: Mill finish, polished, or bead-blasted as required.
- Certification options: EN10204 3.1/3.2, Mill Test Certificate (MTC), Material Test Report (MTR).
Mechanical & Chemical Typical Data (SS 316 / ASTM A182 F316)
Note: Values shown are typical ranges; final delivered material should be validated via MTC/MTR.
| Chemical composition (wt%) — C | ≤ 0.08 |
| Chemical composition — Cr | 16.0–18.0 |
| Chemical composition — Ni | 10.0–14.0 |
| Chemical composition — Mn | ≤ 2.0 |
| Chemical composition — Si | ≤ 1.0 |
| Chemical composition — P | ≤ 0.045 |
| Chemical composition — S | ≤ 0.03 |
| Chemical composition — Mo | 2.0–3.0 |
| Density | ~8.00 g/cm³ |
| Tensile strength (ultimate) | 515–720 MPa (typical forged range) |
| Yield strength (0.2% offset) | ~205–310 MPa |
| Elongation (in 50 mm) | ≥ 40% (typical) |
| Hardness (HRB) | ~70–95 |
Comparison: SS 316 vs SS 304
| Aspect | SS316 (benefits) | SS304 / SS304L (notes) |
| Corrosion resistance | Superior general corrosion and notably better resistance to pitting and crevice corrosion in chloride-containing environments (seawater, brines, chlorides). | Good general corrosion resistance; 304L offers improved resistance to intergranular corrosion after welding due to lower C. |
| Alloying | Contains Mo (≈2–3%) which enhances crevice and pitting resistance. | No Mo; 304L has reduced C (≤0.03) to avoid carbide precipitation. |
| Weldability | Welds well; Mo gives better post-weld corrosion resistance than 304. 316L (low C) further reduces carbide precipitation risk. | 304 welds easily; use 304L for heavy gauge weldments or when post-weld corrosion resistance is required. |
| Strength & toughness | Comparable strength to 304; good toughness at elevated temperatures and cryogenic service. | 304 has similar mechanical properties; 304 (higher C) can offer slightly higher strength than 304L. |
| Applications where preferable | Marine, chemical processing, desalination, chloride-exposed environments, biomedical implants (in some cases), and any service needing higher pitting/crevice resistance. | Food processing, general food & beverage, architectural, and when welding thick sections use 304L. |
| Cost & availability | Typically more expensive than 304 due to Ni and Mo content; widely available. | Generally less expensive; 304L slightly costlier than 304 but still cheaper than 316. |
| Recommendation (practical) | Choose SS316 (or 316L) when chloride exposure, pitting/crevice risk, or superior post-weld corrosion resistance is critical. | Choose SS304 for general use where chlorides aren’t a concern and slight extra strength is desired; choose 304L for heavy weldments or when avoiding intergranular corrosion after welding. |
Manufacturing & Quality Controls
- Raw material traceability: Maintain MTCs linked to heat numbers and lot IDs.
- Forging and machining: Use controlled forging temperatures and precision machining to maintain dimensional tolerances for flanges (per ASME/EN).
- Heat treatment: Annealing per spec, followed by controlled cooling when required.
- Surface finishing: Pickling/passivation to restore corrosion resistance after thermal/mechanical processing.
- Tests typically supplied: PMI or positive material identification, chemical & mechanical tests, UT or RT (radiography) for critical flanges, dimensional inspection, flange face flatness, and hydrostatic tests where applicable.
- Certifications: ISO 9001 quality management, PED (if supplying EU), NORSOK (if serving offshore), and customer-specific audits.
Testing, certification and export documentation
- PMI / chemical composition check (for material verification).
- Hardness testing (HRC/HV) for heat-treated alloys.
- Radiographic testing (RT) or ultrasonic testing (UT) for critical pressure classes.
- Positive Material Identification Certificate (3.1/3.2), MTRs.
- Hydrostatic test of welded assemblies where applicable.
- Third-party inspection (TPI) by client-approved agencies (ABS, BV, DNV, Lloyd’s, SGS).
Packaging & Export Readiness
- Protective packaging: Individual wrapping of SS316 flanges is available on request, wooden crates or pallets with corrosion inhibitors and desiccants.
- Documentation: Commercial invoice, packing list, bill of lading, MTC/MTR (EN 10204 3.1/3.2), test reports, export/import certificates, and COO (certificate of origin).
- Incoterms: Offer EXW, FOB, CFR, CIF depending on customer preference.
- Logistics: Sea freight consolidation for pallets/containers; expedited air shipments for urgent small orders.
Quality assurance & traceability
- Heat-to-part traceability recorded; unique serial/heat numbers laser-etched.
- Full MTRs (ASTM/EN) and 3.1/3.2 certificates issued by default.
- Welding records (WPS/PQR), NDT logs and inspector sign-offs available.
- Continuous improvement via process monitoring and internal audits.
Applications & Industries
- Petrochemical and refineries (process piping, heat exchangers).
- Food & beverage (sanitary piping, hygienic flanges).
- Pharmaceutical (process systems requiring corrosion resistance).
- Water treatment and desalination.
- Power plants (balance-of-plant piping).
- General industrial and structural applications.
Commercial Considerations for Buyers
- MOQ (minimum order quantity): State your standard MOQs and note flexibility for stocked items.
- Lead times: Typical 4–8 weeks depending on size and certification requirements; expedite options for stocked SKUs.
- Pricing factors: Material market price (Ni & Cr), flange type, size, pressure class, testing/certification level, and finish.
- Sample policy: Offer sample pieces or small trial lots for new buyers; provide sample MTCs.
Export Data Table
| Parameter | Typical Export Range / Options | Notes for Exporters |
| Sizes supplied | 1/2″–24″ (ASME B16.5); larger on request | Stock common sizes for faster exports |
| Pressure ratings | 150#–2500# | Match buyer spec (ASME or EN) |
| Material specs | ASTM A182 F316, ASTM A240, UNS S31600 | Include SS 316L (ASTM A182 F316L) as option |
| Face types | RF, FF, RTJ | RTJ for high-pressure/high-integrity applications |
| Surface finish | Mill, 1B, 2B, polished | Sanitary markets often need polished finishes |
| Testing | PMI, Chemical, Mechanical, UT/RT, Hydro | Provide MTC EN 10204 3.1/3.2 on request |
| Packaging | Corrosion-inhibitor wrap, wooden crate | Export-grade packaging prevents transit damage |
| Certifications | ISO 9001, PED, NORSOK (if applicable) | Tailor certifications per target market |
| Lead time | 2–8 weeks typical | Stocked items <2 weeks; custom forged longer |
| Payment terms | T/T, L/C at sight, CAD | Offer competitive payment terms for new buyers |
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