Austenitic · UNS S30400
304 Stainless Steel
304 is the general-purpose austenitic stainless steel — roughly 18% chromium and 8% nickel. It is the default answer for most food, architectural and general corrosion jobs, and it is the wrong answer the moment chlorides or welding enter the picture without the low-carbon L version.
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Austenitic · UNS S30400 · 8.00 g/cm³
At a glance
304 Stainless — The Short Version
| Alloy family | Austenitic (UNS S30400) |
|---|---|
| Density | 8.00 g/cm³ |
| Standards | ASTM A240 · EN 10088-2 · JIS G4305 |
| Forms supplied | Stainless Steel Coil · Stainless Steel Sheet & Plate · Stainless Steel Tube & Pipe · Stainless Steel Bar & Rod · Stainless Steel Profile · Stainless Steel Fittings & Flanges |
Chemistry
304 Chemical Composition Limits
Percent by weight. These are the registered limits, not a typical analysis — a heat that sits anywhere inside them is still 304.
| Element | Limit (% wt) | Element | Limit (% wt) |
|---|---|---|---|
| C | 0.08 max | Mn | 2.00 max |
| P | 0.045 max | S | 0.030 max |
| Si | 0.75 max | Cr | 18.0 – 20.0 |
| Ni | 8.0 – 10.5 | Mo | — |
| N | 0.10 max |
Composition limits are the ASTM A240 registered ranges, which EN 10088-2 refers back to. Mechanical values are typical for the solution-annealed condition, not acceptance minima — the minima are set by the product standard, and the mill certificate reports the measured values for your heat.
Mechanicals
Typical Mechanical Properties (Solution Annealed)
Room temperature. Use these to compare grades — the acceptance figures for your order come from the product standard and are reported on the mill certificate for the actual heat.
| Condition | Tensile (MPa) | Yield (MPa) | Elongation (%) |
|---|---|---|---|
| Annealed | 515 | 205 | 40 |
Cold-worked tempers are available to order — values are quoted with the offer rather than assumed from this table.
Forms
304 in the Forms We Supply
The same grade behaves differently as coil, plate and tube because the forming route sets the surface and the final mechanical condition. Pick the form first.
Stainless Steel Coil
Cold-rolled and hot-rolled coil in 200 / 300 / 400 series.
0.3 – 8.0 mm · 600 – 2,000 mm
Stainless Steel Sheet & Plate
Cold-rolled sheet and hot-rolled plate for structural and decorative use.
0.3 – 120 mm · 1,000 – 2,000 mm
Stainless Steel Tube & Pipe
Seamless and welded round, square and rectangular tube.
Wall 0.5 – 40 mm · OD 6 – 630 mm
Stainless Steel Bar & Rod
Round, flat, square and hexagonal bar, cold drawn or hot rolled.
Ø 3 – 600 mm · —
Stainless Steel Profile
Angle, channel, I-beam and special sections.
Section 20 – 200 mm · —
Stainless Steel Fittings & Flanges
Elbows, tees, reducers, flanges, fasteners and custom fabricated parts.
DN 15 – DN 600 · —
Selection
Choose 304 When — and When Not To
Choose 304 when
General corrosion duty, food contact, architectural trim and indoor fittings. The 18/8 chemistry resists atmospheric and mild chemical attack, welds well, and is stocked in far more gauges and forms than any other stainless grade.
Think again if
Coastal or chloride service, and welded assemblies. Chlorides pit 304; welding sensitizes it unless the low-carbon 304L is specified. If the part sees salt air, chlorinated cleaners or a weld, move to 316L or 2205.
Before you ask
304 — Questions Buyers Ask
Is 304 magnetic?
Slightly magnetic when cold-worked, but essentially non-magnetic in the solution-annealed state. A magnet test that sticks to 304 usually means the part was cold-formed, not that the grade is wrong.
What is the difference between 304 and 304L?
Only carbon: 304L is 304 with a 0.030% maximum carbon instead of 0.08%. The L exists for welding — low carbon avoids carbide precipitation (sensitization) at the weld, so specify 304L for anything that will be welded.
Can 304 be used outdoors near the sea?
Not reliably. Within a few kilometres of salt water, 304 pits and rust-stains. For coastal exposure, specify 316L or a duplex grade.
What finishes does 304 come in?
2B, BA, No.4, hairline and 8K mirror, plus No.1 for hot-rolled plate. The finish is a measurable surface roughness — name the Ra or the mill designation, not "shiny".
Also compare
Other Stainless Grades
- 316L Stainless SteelAustenitic · UNS S31603
- 2205 Stainless SteelDuplex · UNS S32205
- 304L Stainless SteelAustenitic · UNS S30403
- 316 Stainless SteelAustenitic · UNS S31600
- 201 Stainless SteelAustenitic · UNS S20100
- 430 Stainless SteelFerritic · UNS S43000
- 321 Stainless SteelAustenitic · UNS S32100
- 310S Stainless SteelAustenitic · UNS S31008
- All stainless grades →The full stainless grade map
Quote on 304 Stainless Steel
Send grade, thickness and quantity. You get price, lead time, MOQ and certificate type in one reply — and a straight answer if the grade is wrong for the job.