Grade dossier
316LN Stainless Steel for Nitrogen-Strengthened Corrosion Service
A low-carbon, nitrogen-alloyed 316 variant providing higher specified strength and improved pitting-resistance contribution while retaining an austenitic structure.
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 | 0.75 max |
| P | 0.045 max |
| S | 0.030 max |
| Cr | 16.00-18.00 |
| Ni | 10.00-14.00 |
| Mo | 2.00-3.00 |
| N | 0.10-0.16 |
Properties with context
Minimums, typical indicators and delivered condition
Specified annealed flat-product values
| Tensile strength | 550 MPa min |
|---|---|
| 0.2% yield strength | 240 MPa min |
| Elongation | 40% min |
| Hardness | 95 HRBW max |
Selection indicators
| Density | about 8.0 g/cm3 |
|---|---|
| Strength mechanism | Interstitial solid-solution strengthening by nitrogen |
| Corrosion contribution | Nitrogen supports pitting resistance; exposure still governs |
| Welding note | Procedure must preserve joint properties and corrosion performance |
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 316LN 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
Pressure equipment needing higher specified strength
Chemical-process tanks and piping under an approved code
Low-temperature structures after toughness review
Orders requiring explicit S31653 certification
Reasons to stop and review
Confusing 316LN with 316L or 316N
Assuming nitrogen makes the grade seawater-proof
Using strength benefits without code acceptance
Substituting EN 1.4429 by name alone without composition review
Fabrication route
Protect properties through cutting, forming and welding
Account for higher forming load and springback.
Qualify welding for nitrogen retention and corrosion behavior.
Specify S31653, product standard and required mechanical minimums.
Check code allowables, toughness and thickness effects.
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
Pressure-equipment products under approved specifications
Pipe and tube under product-specific standards
Bar, forgings and fittings under their own standards
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 316LN against the controlling question
Procurement FAQ
Questions to close before placing the order
Is 316LN stainless steel magnetic?
Magnetic response depends on microstructure and delivered condition.
Can 316LN 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 316LN 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 S31653 flat product
Outokumpu Supra 316LN/4429 official identity and composition
Outokumpu long-product grade table
Applicable ASME/EN design rules for nitrogen-strengthened stainless steel