Selection summary
Overview
304 is the benchmark austenitic stainless steel for equipment, architectural trim, food-contact fabrication, and general industrial parts. It combines broad availability, formability, weldability, and useful corrosion resistance, but chloride exposure can justify a molybdenum-bearing grade.
This page separates standard-oriented limits from typical reference data. Purchase acceptance comes from the ordered specification and certified material test report.
Names and systems
Identity & standards
Similar designations across ASTM, EN, JIS, and other systems are not automatically interchangeable. Product form and ordered standard control chemistry, properties, dimensions, condition, and testing.
Reference chemistry
Composition
| Element | Reference range | Why it matters |
|---|---|---|
| Carbon | ≤ 0.08% | Strength and carbide control |
| Chromium | 18.0–20.0% | Passive-film formation |
| Nickel | 8.0–10.5% | Austenitic structure and ductility |
Concise grade-family reference only. Confirm every element limit against the current standard for the exact product ordered.
Condition matters
Reference properties
Annealed flat product; verify ordered standard
Annealed flat product; verify ordered standard
Typical room-temperature reference
Environment first
Corrosion behavior
Good atmospheric and many food-processing environments when surfaces are properly finished and cleaned.
Not a default choice for seawater, de-icing salt, warm chloride solutions, or persistent crevices.
Temperature, concentration, deposits, crevices, stress, surface finish, cleaning, and fabrication quality can change service performance.
Service limits
Temperature & service
Check oxidation, creep, and sensitization requirements for sustained elevated-temperature service.
Delivery condition
Heat treatment & condition
304 is normally supplied solution annealed and rapidly cooled when corrosion resistance and ductility must be restored after hot or severe cold processing.
It is not hardened by thermal treatment; cold work can increase strength and magnetic response, so the ordered condition must accompany any property requirement.
Process route
Fabrication
Readily formed and welded; cold work increases strength and may increase magnetic response.
Post-fabrication cleaning and removal of embedded iron are important where appearance and corrosion resistance matter.
Magnetic response: Normally low magnetic response when annealed; cold work can increase it.
Decision boundaries
Comparisons & substitution
Choose 304L instead when welded-service carbon control is required by the product specification or fabrication route.
Review 316/316L when chloride pitting risk exceeds the demonstrated capability of 304; molybdenum does not make 316 universally seawater-proof.
Where it is used
Applications
Ordering scope
Product forms & standards
Plate, sheet, and strip under the applicable flat-product specification and ordered finish.
Bar, rod, shapes, and forgings under the product-specific stainless standard.
Seamless or welded pipe and tube under the ordered dimensional, service, and testing specification.
Decision support
Selection guidance
Choose this grade when
- General corrosion resistance and fabrication ease are the priority.
- A widely stocked, economical austenitic grade is needed.
Review another grade when
- The assembly includes welding followed by severe corrosive service.
- Chlorides, seawater, or salt spray are material selection drivers.
Before ordering
Procurement checklist
Name the governing product standard, edition, dimensions, tolerances, edge, finish, and delivery condition.
Require the exact UNS designation and a material test report; a familiar trade name alone is not an acceptance criterion.
Confirm corrosion environment, design temperature, fabrication route, inspection, certification, marking, and packaging before order release.
Traceable evidence