Duplex
Fasteners
Manufacturer · Mumbai
Why Two Phases Genuinely Beat One
Standard austenitic stainless like 316 gives excellent corrosion resistance and toughness, but its yield strength stays relatively modest — you get corrosion performance, not exceptional strength, and that’s a real limitation in applications needing both simultaneously in a smaller, lighter fastener.
Ferritic stainless grades trade the other way — generally higher strength, but with reduced toughness and, in some grades, weaker resistance to certain corrosion mechanisms. Duplex stainless was developed specifically to sit between these two families rather than choosing one, engineering a controlled roughly 50/50 mix of both microstructures in the same alloy.
The practical result is genuinely useful, not just theoretical — Duplex 2205 delivers roughly twice the yield strength of standard 316, while also improving resistance to chloride stress corrosion cracking, a failure mode that specifically threatens austenitic stainless under combined tensile stress and chloride exposure. That combination is exactly why duplex earns its own category rather than being treated as “just another stainless grade.”
Akbar Fasteners Pvt. Ltd. exports to over 50 countries, and our Duplex 2205 fastener range is verified by chemical composition, mechanical, and phase-balance testing under our ISO 9001:2015 quality system.
Where This Material Genuinely Applies
Genuine High Strength-to-Weight Ratio
Roughly twice the yield strength of standard 316 allows smaller, lighter fasteners for the same load.
Genuine Chloride SCC Resistance
Dual-phase microstructure specifically resists chloride stress corrosion cracking better than austenitic alone.
Cost-Sensible Between Standard and Super Duplex
Genuine performance step above 316 without the cost premium of super duplex or specialty alloys.
Verified Phase Balance & Properties
Batch testing confirms genuine austenite-ferrite ratio and mechanical properties for every lot.
316 → Duplex 2205 → Super Duplex — a Clear Step-Up Path
SS 316 / 316L / 316H
Fully austenitic, molybdenum-alloyed. Genuinely sufficient for most marine and chemical exposure without needing dual-phase strength.
View SS 316 →Duplex 2205 (This Page)
~50/50 austenite-ferrite. The step up when higher strength or better chloride SCC resistance is genuinely needed.
You Are HereSuper Duplex S32750
Higher-alloyed duplex family for the most aggressive chloride and high-pressure offshore service.
View Super Duplex →316 vs Duplex 2205 — Quick Reference
Confirming genuine strength or chloride SCC requirements before ordering avoids overpaying for capability the application may not need. This table is the quick reference we use with buyers before quoting.
| Aspect | SS 316 | Duplex 2205 |
|---|---|---|
| Microstructure | Fully austenitic | ~50% austenite / ~50% ferrite |
| Yield Strength | Standard | Roughly 2x higher |
| Chloride SCC Resistance | Moderate | Significantly improved |
| Typical Use | General marine/chemical | High-strength, chloride-critical structural |
Duplex 2205 Specification Details
Nominal Composition
- Chromium 22.0 – 23.0%
- Nickel 4.5 – 6.5%
- Molybdenum 3.0 – 3.5%
- Nitrogen 0.14 – 0.20%
Typical Mechanical Range
- Tensile Strength 620 MPa Min
- Yield Strength 450 MPa Min
- Hardness ≤290 HB
- Elongation 25% Min
Fastener Types We Manufacture
- Bolts & Studs Hex, Threaded Rod
- Nuts Hex, Hex Jam
- Washers Flat, Spring
- Custom Sizes On Request
Application Areas
Wherever genuine high strength and chloride SCC resistance are both needed simultaneously.
Offshore Oil & Gas Platforms
structural fastening
Desalination Plants
process equipment fastening
Marine & Coastal Bridge Structures
corrosion-resistant hardware
Chemical Tanker & Process Vessels
corrosion resistance needs
Pulp & Paper Processing Equipment
with structural strength
Subsea Pipeline & Riser Systems
corrosion-resistant needs
Water & Wastewater Treatment
corrosion-resistant fastening
General High-Strength Corrosive Assembly
strength and corrosion resistance
Standard Export Documentation
Prepared as standard practice for every Duplex 2205 fastener shipment.
Mill Test Certificate (MTC)
Heat number, chemical composition, and mechanical property verification for every lot.
Ferrite Content Report
Confirms the actual austenite-ferrite phase balance falls within the specified duplex range.
Certificate of Conformance
Confirms the shipment matches the purchase order grade/size specification in full.
Certificate of Origin (COO)
Confirms India as country of manufacture for destination customs purposes.
NABL Accredited Test Reports
Independent mechanical, dimensional, and corrosion testing available on request.
Commercial Invoice & Packing List
Itemized value, Incoterm, and detailed carton/weight breakdown for customs clearance.
Internationally Recognised Standards Coverage
Related Fastener Grades & Materials
Super Duplex S32750 Fasteners
Our higher-alloyed duplex family for the most aggressive chloride and offshore service.
View Super Duplex →SS 316 / 316L / 316H Fasteners
Our standard marine-grade austenitic family, sufficient where dual-phase strength isn’t required.
View SS 316 Guide →SS 317 Fasteners
Our higher-molybdenum austenitic grade, when corrosion resistance matters more than strength.
View SS 317 Guide →Stainless Steel Fasteners Manufacturer India
Our broader stainless steel fastener manufacturing capability across all major grades.
View SS Manufacturer Guide →High Strength,
Genuine Chloride Resistance
Tell us your strength requirement and chloride exposure severity — we’ll confirm whether Duplex 2205 is the right fit and quote with full documentation. Akbar Fasteners Pvt. Ltd. responds within 24 hours.
Sales: +91 724 0000 733 · Support: +91 800 9315 333 · sales@akbarfasteners.in