Grade dossier
304L Stainless Steel for Welding and Fabrication
The low-carbon 304 variant commonly selected for welded fabrication when resistance to weld sensitization is a procurement requirement.
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 | 18.00-20.00 |
| Ni | 8.00-12.00 |
| N | 0.10 max |
Properties with context
Minimums, typical indicators and delivered condition
Specified annealed flat-product values
| Tensile strength | 485 MPa min |
|---|---|
| 0.2% yield strength | 170 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 |
| Welded fabrication | Low carbon reduces sensitization risk |
| 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 304L 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
Welded tanks and assemblies
Food and process equipment after service review
Sheet-metal fabrication
Components requiring 304L documentation
Reasons to stop and review
Chloride service requiring 316L or higher
Using dual certification without checking design temperature
Crevices and deposits without exposure review
Assuming low carbon removes all weld-quality controls
Fabrication route
Protect properties through cutting, forming and welding
Good forming and welding characteristics in the annealed condition.
Qualified procedures still need heat input, filler and shielding control.
Post-weld cleaning can be critical to corrosion performance.
Dual-certified 304/304L material must be checked against the controlling code and service.
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
Pipe and tube to separate standards
Fabricated vessels and 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 304L against the controlling question
Procurement FAQ
Questions to close before placing the order
Is 304L stainless steel magnetic?
Magnetic response depends on microstructure and delivered condition.
Can 304L 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 304L 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 304L/4307 and 304L/4306 data
worldstainless fabrication and corrosion guidance