Grade dossier
304N Stainless Steel for Nitrogen-Strengthened Applications
A nitrogen-alloyed 304 variant offering higher specified strength while retaining an austenitic structure and broadly similar general corrosion behavior to 304.
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 | 0.08 max |
|---|---|
| Mn | 2.00 max |
| Si | 0.75 max |
| P | 0.045 max |
| S | 0.030 max |
| Cr | 18.00-20.00 |
| Ni | 8.00-10.50 |
| 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 | 30% min |
| Hardness | 95 HRBW max |
Selection indicators
| Density | about 7.9-8.0 g/cm3 |
|---|---|
| Strength mechanism | Interstitial solid-solution strengthening by nitrogen |
| Magnetic response | Normally low annealed; can increase after cold work |
| Corrosion position | Comparable family to 304; service review still required |
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 304N 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 vessels and structural components needing higher specified strength
Tanks and process equipment under a suitable code
Components where strength can reduce section after design review
Orders requiring UNS S30451 traceability
Reasons to stop and review
Confusing 304N with low-carbon 304LN
Assuming nitrogen alone solves chloride corrosion
Using higher strength without code acceptance
Substituting standard 304 without recalculating design
Fabrication route
Protect properties through cutting, forming and welding
Account for higher strength in forming loads and springback.
Qualify welding for nitrogen retention and joint properties.
State S30451 explicitly on the purchase order.
Check thickness-dependent code allowables and toughness requirements.
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 components under approved code rules
Pipe and tube to product-specific specifications
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 304N against the controlling question
Procurement FAQ
Questions to close before placing the order
Is 304N stainless steel magnetic?
Magnetic response depends on microstructure and delivered condition.
Can 304N 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 304N 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 chemistry and mechanical requirements for UNS S30451
Outokumpu Core 304N/4315 product identification
Sandia Type 304 alloy technical reference
ASTM A959 harmonized grade composition