Grade dossier
304 Stainless Steel Properties and Selection
The general-purpose 18/8 austenitic grade used across fabrication, food equipment, architecture and process hardware when the service does not demand a higher chloride margin.
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 max |
Properties with context
Minimums, typical indicators and delivered condition
Specified annealed flat-product values
| Tensile strength | 515 MPa min |
|---|---|
| 0.2% yield strength | 205 MPa min |
| Elongation | 40% min |
| Hardness | 92 HRB max |
Selection indicators
| Density | about 8.0 g/cm3 |
|---|---|
| PRE indicator | about 18-20; not a service limit |
| Work hardening | High |
| Heat treatment | Not hardened by thermal treatment |
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 304 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
General fabrication
Food and beverage equipment after hygienic design review
Architectural interiors and mild exteriors
Tanks, covers and formed components
Reasons to stop and review
Warm stagnant chloride solutions
Crevices or deposits without corrosion review
High-temperature welded service where carbon control is specified
Automatic substitution for 316
Fabrication route
Protect properties through cutting, forming and welding
Excellent general formability, with higher springback than carbon steel.
Use sharp tools and continuous feeds to manage work hardening.
Common fusion processes are suitable with a qualified welding procedure.
Remove heat tint and contamination where corrosion performance matters.
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.
Sheet and coil
Plate
Bar and wire
Pipe and tube under their own product 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.
Interactive selection check
Test 304 against the controlling question
Procurement FAQ
Questions to close before placing the order
Is 304 stainless steel magnetic?
Low when annealed; may increase after cold work or welding
Can 304 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 304 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 flat-rolled composition and mechanical requirements
Atlas Grade Datasheets: 304, 304L and 304H
Outokumpu Core 304/4301 range data
worldstainless mechanical, physical and corrosion guidance