Grade dossier
2507 Super Duplex Stainless Steel for Severe Chloride Service
A super duplex grade combining high strength with strong resistance to chloride pitting, crevice corrosion and 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 | 1.20 max |
| Si | 0.80 max |
| P | 0.035 max |
| S | 0.020 max |
| Cr | 24.00-26.00 |
| Ni | 6.00-8.00 |
| Mo | 3.00-5.00 |
| N | 0.24-0.32 |
| Cu | 0.50 max |
Properties with context
Minimums, typical indicators and delivered condition
Specified annealed flat-product values
| Tensile strength | 795 MPa min |
|---|---|
| 0.2% yield strength | 550 MPa min |
| Elongation | 15% min |
| Hardness | 310 HBW max |
Selection indicators
| Density | about 7.8 g/cm3 |
|---|---|
| PRE guidance | typically at least 40 by common formulas |
| Strength | high; buckling and fatigue still require design |
| Temperature | observe duplex code and toughness limits |
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 2507 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
Offshore and subsea piping
Desalination and seawater systems after design review
Flue-gas and chemical-process equipment
High-pressure chloride-bearing service
Reasons to stop and review
Calling the grade immune to seawater crevice corrosion
Unqualified weld heat input or repair cycles
Extended exposure in harmful intermetallic temperature ranges
Ordering without NORSOK or project test details when required
Fabrication route
Protect properties through cutting, forming and welding
Use approved super-duplex filler and controlled heat input.
Limit interpass temperature and qualify repair welding.
Specify ferrite, impact and corrosion testing as needed.
Remove heat tint and restore passivity.
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 strip to ASTM A240/A240M
Pipe and tube under super-duplex product standards
Bar, forgings, fittings and flanges
Offshore and desalination assemblies
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 2507 against the controlling question
Procurement FAQ
Questions to close before placing the order
Is 2507 stainless steel magnetic?
Magnetic response depends on microstructure and delivered condition.
Can 2507 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 every product form?
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 2507 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 S32750 flat product
Outokumpu Forta SDX 2507 official datasheet
NORSOK M-630/MDS requirements when contractually applicable
Applicable pressure-code and project corrosion qualification