Grade dossier
2101 Lean Duplex Stainless Steel for Efficient Strength
A lean duplex grade that combines duplex strength with lower nickel and molybdenum content for tanks, structures and moderately corrosive process service.
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 | 0.040 max |
|---|---|
| Mn | 4.00-6.00 |
| Si | 1.00 max |
| P | 0.040 max |
| S | 0.030 max |
| Cr | 21.00-22.00 |
| Ni | 1.35-1.70 |
| Mo | 0.10-0.80 |
| N | 0.20-0.25 |
| Cu | 0.10-0.80 |
Properties with context
Minimums, typical indicators and delivered condition
Specified annealed flat-product values
| Tensile strength | 650 MPa min |
|---|---|
| 0.2% yield strength | 450 MPa min |
| Elongation | 30% min |
| Hardness | 290 HBW max |
Selection indicators
| Density | about 7.8 g/cm3 |
|---|---|
| Strength | roughly twice conventional austenitic stainless |
| Thermal expansion | lower than 304/316 austenitic grades |
| Design note | Check duplex temperature and phase-balance 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 2101 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
Storage tanks and process vessels
Structural members and bridges
Pulp-and-paper and water equipment
Weight-reduced fabrications after buckling review
Reasons to stop and review
Treating PRE as a seawater guarantee
Using austenitic welding practice without duplex controls
Prolonged service above duplex code limits
Ordering without impact or phase-balance requirements
Fabrication route
Protect properties through cutting, forming and welding
Use a qualified duplex filler and controlled heat input.
Control interpass temperature and avoid autogenous weld assumptions.
Remove heat tint and iron contamination.
Verify ferrite, impact and corrosion testing where required.
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
Welded and seamless pipe/tube under applicable standards
Bar, forgings and fittings
Fabricated tanks and structural components
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.
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Interactive selection check
Test 2101 against the controlling question
Procurement FAQ
Questions to close before placing the order
Is 2101 stainless steel magnetic?
Magnetic response depends on microstructure and delivered condition.
Can 2101 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 2101 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 S32101 flat product
Outokumpu Forta LDX 2101 official datasheet
Applicable duplex welding qualification standard
Project corrosion and design-code requirements