Grade dossier
2205 Duplex Stainless Steel Properties and Selection
The most widely used duplex grade, combining substantially higher strength than common annealed austenitic grades with improved resistance to chloride stress-corrosion cracking.
Identity before substitution
Define the grade, product and condition together
A familiar grade name is not a complete purchase specification. Product form, controlling standard, dimensions, condition, finish, certification and service environment determine whether the delivered material is suitable.
Composition control
ASTM A240/A240M flat-product chemistry
Limits are not heat analysis targets
The table summarizes grade limits commonly used for plate, sheet and strip. Pipe, tube, bar, forgings and cast products can be governed by different specifications. Always place the product standard and edition on the purchase order.
| C | 0.030 max |
|---|---|
| Mn | 2.00 max |
| Si | 1.00 max |
| P | 0.030 max |
| S | 0.020 max |
| Cr | 22.00-23.00 |
| Ni | 4.50-6.50 |
| Mo | 3.00-3.50 |
| N | 0.14-0.20 |
Properties with context
Minimums, typical indicators and delivered condition
Specified annealed flat-product values
| Tensile strength | 655 MPa min |
|---|---|
| 0.2% yield strength | 450 MPa min |
| Elongation | 25% min |
| Condition | Solution annealed S32205 flat product |
Selection indicators
| Density | about 7.8 g/cm3 |
|---|---|
| PRE indicator | about 34-36; not a service limit |
| Magnetic response | Magnetic because of ferrite content |
| Service temperature | Review limits; prolonged high temperature can embrittle duplex |
Values depend on product form, thickness, test orientation, condition and governing edition. Use the mill test certificate and the purchase specification for acceptance, not a web table alone.
Selection boundary
Where 2205 belongs and where to escalate
Grade selection is an environmental decision, not a popularity contest. Review the complete medium, temperature, geometry, fabrication, cleaning and inspection requirements.
Good reasons to evaluate it
Chemical-process equipment
Oil, gas and pulp-processing equipment
Chloride-bearing service after full exposure review
Weight-sensitive structures using the higher design strength
Reasons to stop and review
Calling material only 2205 where the UNS matters
Uncontrolled welding or autogenous welding assumptions
Prolonged elevated-temperature service without metallurgical review
Forming with equipment sized only for 304 or 316
Fabrication route
Protect properties through cutting, forming and welding
Higher strength increases forming force and springback.
Welding must control heat input, interpass temperature and phase balance.
Filler and shielding practice should be qualified for duplex metallurgy.
Specify solution-annealed condition, inspection and surface restoration.
Supply definition
Product form changes the applicable requirements
Do not send an RFQ that names only the grade. State form, governing standard, dimensions, tolerances, finish, edge or end condition, quantity, certification and inspection.
Plate, sheet and coil
Pipe and tube under product-specific standards
Bar and forgings
Welded process equipment and structures
Certificate checkpoint
Request heat identity, chemical analysis, mechanical results and compliance to the exact product specification. Add PMI, corrosion testing or supplementary examination only when the application requires it.
Interactive selection check
Test 2205 against the controlling question
Procurement FAQ
Questions to close before placing the order
Is 2205 stainless steel magnetic?
Magnetic response depends on microstructure and delivered condition.
Can 2205 replace another grade?
Only after checking the governing standard, composition, mechanical properties, corrosion exposure, fabrication route and certification. A commercial name is not a substitution approval.
Does the table apply to pipe, tube and bar?
Not automatically. The values shown use flat-product requirements as a reference. Other forms can use different product standards, dimensions and tests.
What should a 2205 RFQ include?
Product form, standard and edition, UNS or EN designation, dimensions, tolerances, finish, quantity, service, fabrication, certificate and inspection requirements.
Sources, scope and RFQ
Use traceable grade data, then specify the actual product
ASTM A240/A240M requirements for UNS S32205 flat product
Outokumpu Forta DX 2205 range data
Atlas Grade Datasheet: 2205
worldstainless duplex design and corrosion guidance