Austenitic · UNS S30403
304L Stainless Steel
304L is 304 with carbon pulled down to 0.030% maximum. The chemistry is otherwise the same, and so is the corrosion behavior — the difference only shows up when the part is welded, because low carbon stops chromium carbide from precipitating at the weld and sensitizing the heat-affected zone.
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Austenitic · UNS S30403 · 8.00 g/cm³
At a glance
304L Stainless — The Short Version
| Alloy family | Austenitic (UNS S30403) |
|---|---|
| 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
304L Chemical Composition Limits
Percent by weight. These are the registered limits, not a typical analysis — a heat that sits anywhere inside them is still 304L.
| Element | Limit (% wt) | Element | Limit (% wt) |
|---|---|---|---|
| C | 0.030 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 – 12.0 | 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 | 485 | 170 | 40 |
Cold-worked tempers are available to order — values are quoted with the offer rather than assumed from this table.
Forms
304L 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.
304L Stainless Steel Coil
Cold-rolled and hot-rolled coil in 200 / 300 / 400 series.
0.3 – 8.0 mm · 600 – 2,000 mm
304L 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
304L Stainless Steel Tube & Pipe
Seamless and welded round, square and rectangular tube.
Wall 0.5 – 40 mm · OD 6 – 630 mm
304L Stainless Steel Bar & Rod
Round, flat, square and hexagonal bar, cold drawn or hot rolled.
Ø 3 – 600 mm · —
304L Stainless Steel Profile
Angle, channel, I-beam and special sections.
Section 20 – 200 mm · —
304L Stainless Steel Fittings & Flanges
Elbows, tees, reducers, flanges, fasteners and custom fabricated parts.
DN 15 – DN 600 · —
Selection
Choose 304L When — and When Not To
Choose 304L when
Any welded 304 assembly — tanks, pipework, railings, frames — where the weld must keep its corrosion resistance without a post-weld solution anneal. If the drawing says "304" but the part is welded, 304L is the technically correct order.
Think again if
Non-welded indoor work where standard 304 is stocked in more gauges and is cheaper. And 304L is still an 18/8 grade — it does not gain chloride resistance, so coastal or chlorinated duty still needs 316L or a duplex grade.
Before you ask
304L — Questions Buyers Ask
Is 304L the same as 304?
Chemically almost identical — the only deliberate change is carbon: 0.030% max for 304L against 0.08% for 304. The L exists for welding, not for corrosion or strength.
When should I specify 304L instead of 304?
Whenever the part will be welded. Low carbon prevents sensitization in the heat-affected zone, so the weld keeps its corrosion resistance without re-annealing.
Does 304L cost more than 304?
Marginally, and the premium is small compared with re-annealing or a failed weld. Most mills now produce 304L as the default for sheet and strip, so the gap is narrow.
Is 304L magnetic?
No more than 304 — essentially non-magnetic in the annealed state, slightly magnetic after heavy cold work.
Also compare
Other Stainless Grades
- 304 Stainless SteelAustenitic · UNS S30400
- 316L Stainless SteelAustenitic · UNS S31603
- 2205 Stainless SteelDuplex · UNS S32205
- 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 304L Stainless Steel
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