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DUPLEX STAINLESS STEEL | HIGH-STRENGTH CORROSION-RESISTANT FASTENERS

Duplex Stainless Steel 2205 Bolts, Nuts, Studs & Washers | UNS S31803 / S32205

Duplex 2205 Fasteners combine high mechanical strength with strong resistance to chloride stress-corrosion cracking, pitting and crevice corrosion. Aanuraj supplies bolts, studs, nuts, washers and custom threaded fasteners for demanding industrial and export applications.

UNS S31803UNS S32205EN 1.4462ASTM F51 / F60ASTM A1082 BoltingSAF 2205
Technical Contents - Jump Directly to a Section OverviewGrade NamesKey FeaturesChemistryMechanicalPRENSolution AnnealingStandardsDimensionsFastener TypesApplicationsWhy AanurajExport KeywordsBUY / TECH EXPERT

1. Duplex 2205 Fasteners - Technical Overview

Duplex 2205 is a ferritic-austenitic stainless steel family with high strength and strong resistance to chloride-related corrosion.

For designers and engineers, the two UNS designations most commonly associated with 2205 are S31803 and S32205. Both are associated with EN 1.4462 and the 22Cr-5Ni-3Mo duplex family, but the controlled composition limits are not identical. Specify the exact UNS grade on the purchase order and MTC.

~50/50Duplex ferrite + austenite structure
450 MPa+Typical minimum proof/yield basis for 2205 product standards
~35Typical PREN region for 2205
2xApprox. proof-strength advantage vs many austenitic grades
Engineering note: Finished fastener acceptance requirements depend on the specified fastener standard, product form, size, heat treatment, tests and purchase specification. Do not use generic 2205 bar values as a substitute for the required fastener specification.

2. Duplex 2205 - Different Names, Grades & Designations

Designation / NameIdentificationUse in technical documents
Duplex 2205Common commercial nameGeneral engineering and procurement description.
UNS S31803Duplex stainless steelOriginal/common 2205 UNS designation; associated with ASTM F51 in forging/product-form references.
UNS S32205Duplex stainless steelMore tightly controlled 2205 chemistry; associated with ASTM F60 in forging/product-form references.
EN 1.4462X2CrNiMoN22-5-3European material designation.
W.Nr. 1.44621.4462Werkstoff number used in European documentation.
DIN X2CrNiMoN 22 5 3Duplex 22Cr-5Ni-3Mo-NDIN chemical designation.
SAF 2205Trade/product nameWell-known commercial name; use UNS/EN designation for purchase clarity.
ASTM A182 F51 / F60Forged product gradesApplicable to pressure-component forgings/product forms, not a universal finished-fastener standard.
ASTM A1082/A1082MDuplex stainless bolting specificationSpecial-purpose high-strength duplex/stainless bolting specification; grade selection and size requirements must be checked.

3. Key Features of Duplex Stainless Steel 2205 Fasteners

High Mechanical Strength
Higher proof strength than conventional 304/316 austenitic stainless grades can allow efficient bolted-joint design.
Chloride SCC Resistance
Strong resistance to stress-corrosion cracking in chloride-bearing environments.
Pitting & Crevice Resistance
Chromium, molybdenum and nitrogen contribute to localized-corrosion resistance.
Hydrogen Sulfide Service
2205 is used in selected sour-service applications subject to the applicable NACE/ISO requirements.
Good Wear & Erosion Resistance
Duplex metallurgy provides useful resistance to erosion-corrosion and corrosion fatigue.
Lower Nickel Than Many Austenitics
2205 achieves high strength and corrosion resistance with a lower nickel level than many high-alloy austenitic grades.

4. Duplex 2205 Chemical Composition - All Principal Elements

ElementS31803 / F51 reference, wt.%S32205 / F60 reference, wt.%Function / design relevance
Carbon (C)0.030 max.0.030 max.Low carbon limits carbide formation.
Silicon (Si)1.00 max.1.00 max.Deoxidation/process element.
Manganese (Mn)2.00 max.2.00 max.Strength/process control.
Phosphorus (P)0.030 max.0.030 max.Controlled residual element.
Sulfur (S)0.020 max.0.020 max.Controlled residual element.
Chromium (Cr)21.0 - 23.022.0 - 23.0Passive film and localized corrosion resistance.
Nickel (Ni)4.5 - 6.54.5 - 6.5Austenite stabilization and toughness.
Molybdenum (Mo)2.5 - 3.53.0 - 3.5Pitting/crevice corrosion resistance.
Nitrogen (N)0.08 - 0.200.14 - 0.20Austenite balance, strength and pitting resistance.
Iron (Fe)BalanceBalancePrincipal matrix element.

The S31803/S32205 chemistry ranges above are presented as procurement-oriented references. Exact limits depend on the applicable product specification and edition; the purchase specification and MTC govern.

5. Duplex 2205 Mechanical & Physical Properties

PropertyS31803 / 2205 referenceS32205 / 2205 referenceEngineering significance
0.2% Proof / Yield Strength450 MPa min. in common ASTM A182-type reference450 MPa min. in common ASTM A182-type referenceHigh load-carrying capability.
Tensile Strength620 MPa min.655 MPa min.Ultimate tensile capacity reference.
Elongation25% min.25% min.Ductility reference.
Hardness293 HB max. in common A182-type reference293 HB max. in common A182-type referenceUseful for machining and acceptance control.
DensityApprox. 7.8 g/cm3Approx. 7.8 g/cm3Useful for weight estimation.
Elastic ModulusApprox. 200 GPaApprox. 200 GPaUseful for stiffness calculations.
Thermal ConductivityApprox. 15 W/m.KApprox. 15 W/m.KThermal design reference.
Poisson RatioApprox. 0.30Approx. 0.30Elastic analysis reference.
Melting PointApprox. 1350 CApprox. 1350 CGeneral physical-property reference.
Do not mix standards: ASTM A1082/A1082M is a dedicated high-strength bolting specification, while ASTM A182, A276/A479 and A240 cover different product forms. Select the standard according to the actual component and project requirement.

6. PREN of Duplex 2205 - Pitting Resistance Equivalent Number

PREN formula: PREN = %Cr + 3.3 x %Mo + 16 x %N.

S31803
Using representative/minimum chemistry values, PREN is commonly in the low-30s. Actual value depends on the heat chemistry.
S32205
With tighter Mo and N floors, S32205 is commonly associated with a PREN around 35 when calculated from representative chemistry.
Engineering Use
PREN is a comparative indicator, not a complete corrosion qualification. Temperature, chlorides, pH, surface condition and stress also matter.

7. Duplex 2205 Solution Annealing & Quenching

01Heat
1020-1100 C
02Soak
Heat complete section
03Solution Anneal
Restore balanced structure
04Rapid Cool
Water preferred
05Inspect
Dimensions + hardness + MTC
Recommended material heat treatment: 1020-1100 C (1870-2010 F) followed by rapid cooling, commonly water quenching for 2205. The exact procedure for a forged fastener should follow the specified material/fastener standard, furnace procedure and qualified manufacturing route.

8. Duplex 2205 Fasteners - Standards & Dimensional References

Component / requirementCommon referencePurpose
Special-purpose boltingASTM A1082/A1082M + ASTM A962/A962MHigh-strength duplex/stainless bolting; includes requirements for testing, finish, threads, marking and certification through referenced requirements.
Forged pressure componentsASTM A182 F51 / F60Duplex forging material grades for pressure-related components.
Bar / round stockASTM A276 / ASTM A479Stainless bar and pressure-vessel-quality bar product forms.
Plate / sheetASTM A240Flat-product material reference.
Metric hex boltsISO 4014 / ISO 4017; DIN 931 / DIN 933Dimensional and thread configuration reference.
Inch hex boltsASME B18.2.1Inch-series hex bolt dimensions.
Metric hex nutsISO 4032 / DIN 934Metric hex nut dimensions.
Inch hex nutsASME B18.2.2Inch nut dimensions.
ThreadsASME B1.1 / ISO metric thread standardsUNC/UNF and metric thread geometry/tolerances.
WashersISO 7089 / DIN 125 / ASME B18.21.1Plain washer dimensions.

9. Duplex 2205 Fastener Dimensions - Designer Reference

Metric Hex Bolts
M6 to M100 can be supplied subject to product standard, manufacturing route and drawing. Common engineering references include ISO 4014/4017 and DIN 931/933.
Inch Hex Bolts
Common inch sizes from 1/4 in to 2 in and larger project-specific sizes can be manufactured to ASME dimensional requirements.
Studs / Threaded Rod
Full-thread and double-end configurations can be supplied in metric or inch threads to drawing/specification.
Hex Nuts
Standard and heavy-hex nuts can be produced to the selected dimensional standard and matching thread.
Washers
Plain washers can be supplied in metric and USS/SAE inch configurations according to project specification.
Custom Fasteners
Special lengths, reduced shanks, non-standard threads and drawing-controlled components can be reviewed.

10. Types of Duplex 2205 Fasteners

Hex Bolts
Full-thread and partial-thread hex bolts for flanges, structures and equipment.
Hex Nuts
Matching nuts for duplex bolting assemblies.
Full Threaded Studs
Threaded studs for flanges, valves, pressure equipment and structural connections.
Stud Bolts
Double-end and full-thread configurations for industrial bolted joints.
Washers
Plain washers for load distribution and surface protection.
U-Bolts / Special Parts
Custom-bent or drawing-specific duplex components for pipe supports and assemblies.

11. Important Pointwise Selection Guide for Designers & Engineers

1. Define the exact UNS grade
Write S31803 or S32205 instead of only writing "2205".
2. Define the fastener standard
Material grade alone does not define finished fastener dimensions and acceptance tests.
3. Specify thread system
State metric pitch or UNC/UNF thread, tolerance class and fit.
4. Specify heat treatment
For duplex material, solution annealing and rapid cooling are critical to maintaining the intended phase balance.
5. Consider service environment
Check chlorides, temperature, H2S, pH, stress and corrosion mechanism.
6. Require traceability
Heat number, MTC, PMI and required inspection documents should be stated in the purchase order.

12. Duplex 2205 Bolts, Nuts & Washers - Applications

Oil & Gas
Flanges, valves, piping, offshore equipment and sour-service applications subject to project qualification.
Petrochemical
Process equipment and bolted joints exposed to chlorides and aggressive media.
Chemical Plants
Reactors, tanks, piping and equipment requiring high strength plus corrosion resistance.
Marine & Offshore
Marine structures and equipment exposed to chloride-rich environments.
Water & Desalination
Pumps, piping and equipment where chloride corrosion is a design concern.
Power & Infrastructure
Heavy-duty structural and process applications requiring high-strength stainless bolting.

13. Why Aanuraj for Duplex 2205 Fasteners?

Hot Forging Expertise
Aanuraj's orange/yellow identity represents the hot-forging process used to manufacture demanding fastener components.
Duplex & Exotic Grade Knowledge
Technical experience across stainless, duplex, super duplex and high-nickel fasteners.
Material Traceability
Heat identification, PMI and MTC documentation can be arranged according to project requirements.
Machining + Thread Rolling
Forging, CNC machining and thread-rolling capability supports controlled production.
Custom Engineering
Metric, inch, long-length studs, special bolts, nuts, washers and drawing-specific parts.
Quality Focus
Inspection and documentation support for industrial and critical bolting requirements.

14. Why Duplex 2205 Instead of Conventional Austenitic Stainless?

Design considerationDuplex 2205Engineering implication
StrengthHigh proof strengthCan support high-load bolting designs; verify fastener-specific allowable stresses.
Chloride SCCStrong resistanceUseful for marine, offshore and chloride-bearing service.
Pitting / CreviceGood to high resistanceMo + Cr + N chemistry improves localized-corrosion resistance.
Nickel contentLower than many high-Ni austeniticsCan provide a useful alloying-cost balance.
MicrostructureFerritic + austeniticHeat treatment and cooling rate are important to preserve phase balance.

15. European & Export Keywords - Duplex 2205 Fasteners

European countries: Germany, United Kingdom, France, Italy, Spain, Netherlands, Belgium, Poland, Sweden, Norway, Denmark, Finland, Austria, Switzerland, Czech Republic, Portugal, Greece, Ireland, Romania, Hungary and European Union markets.

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Technical note: This page is an engineering reference, not a substitute for the current edition of the specified ASTM/ASME/EN/DIN standard, project specification or certified MTC. Product-form and fastener-specific requirements must be verified before purchase or certification.