Grade 304L
Austenitic stainless · 1.4307, AISI 304L
Low-carbon 304 for heavier welded sections.
Data sheet
| Designations | AISI 304L / SAE 30304L · UNS S30403 · EN 1.4307 (X2CrNi18-9) |
|---|---|
| Standards | EN 10088-2, ASTM A240 |
| Used for | welded tanks, food plant |
Offered in
Metallurgy
Reference data for Type 304L Stainless Steel (Extra-Low Carbon), against ASTM A240, ASTM A276, EN 10088-2.
Elemental composition
X2CrNi18-9 to 1.4307
- Chromium 18,50%17,50–19,50%
- Nickel 10,00%8,00–12,00%
- Nitrogen 0,050%max 0,10%
- Carbon 0,020%max 0,030%
- Other additions 1,54%Mn, Si, P, S
- Iron 69,89%Balance
Proportions use the normalised midpoint of each specified range. The midpoint is a derived figure, not something the standard states: read the table for what is actually specified.
Performance profile
Comparative scores out of ten, for weighing one grade against another
These are relative ratings, not measured properties, and they carry no units. Use them to narrow a shortlist, then work from the specified values.
Composition as specified
| Element | Specified | Nominal |
|---|---|---|
| Iron Fe | Balance | 69,89% |
| Carbon C | max 0,030%cap | 0,020% |
| Chromium Cr | 17,50–19,50% | 18,50% |
| Nickel Ni | 8,00–12,00% | 10,00% |
| Manganese Mn | max 2,00%cap | 1,00% |
| Silicon Si | max 0,75%cap | 0,50% |
| Nitrogen N | max 0,10%cap | 0,050% |
| Phosphorus P | max 0,045%cap | 0,025% |
| Sulphur S | max 0,030%cap | 0,015% |
A cap is a ceiling, not a quantity: a heat may contain far less. The nominal column is the midpoint of each range, used for the chart's proportions only.
Mechanical and physical properties
| Property | Value |
|---|---|
| Tensile strength, ultimate | 485 MPa70,3 ksi |
| Yield strength, 0,2% offset | 170 MPa24,7 ksi |
| Elongation at break | 40% |
| Hardness | 160 HBW / 85 HRB |
| Modulus of elasticity | 193 GPa28 Mpsi |
| Density | 8 g/cm³0,29 lb/in³ |
| Thermal conductivity | 16,2 W/(m·K)112,4 BTU·in/(hr·ft²·°F) |
| Thermal expansion | 17,2 µm/(m·K)9,6 µin/(in·°F) |
Test condition not yet confirmed. These figures are typical values for the grade; the condition a bar was supplied in changes them materially, so ask us for the mill certificate before designing to a number.
Pitting resistance
PREN 19,3
Cr + 3,3 Mo + 16 N, across the full specified composition
- Freshwater0–20
- Brackish20–32
- Seawater32–40
- Extreme offshoreover 40
A standard states its elements as ranges, so a grade has a window rather than a single score. The bar is that window; the tick is the midpoint.
Corrosion and fabrication
Chloride and marine service
Similar to 304; moderate resistance, prone to crevice/pitting in marine salt-spray without regular cleaning.
Acidic and chemical media
Resistant to organic and oxidizing acids; immune to intergranular attack across weld heat-affected zones (HAZ).
Sensitisation and thermal behaviour
Extremely high resistance due to low carbon (<=0.030%); eliminates need for post-weld solution annealing.
Welding
Superior (highest in standard austenitic family); minimal carbide precipitation during heavy-section welding.
Machining and cold forming
Machinability index 45% relative to AISI 1212. Excellent; low work hardening yield allows severe drawing, spin forming, and stamping.
Where it is used
- Welded chemical reaction vessels and piping
- Brewery fermentation tanks and distillation columns
- Cryogenic storage tanks and vacuum insulated containers
- Mining and wastewater processing fluid systems
Chemical Processing · Brewing & Distilling · Cryogenics · Wastewater Treatment
Performance scores in full
The same six scores the profile plots, as numbers.
| Property | 304L |
|---|---|
| Corrosion resistance | 7.8 / 10 |
| Weldability | 9.8 / 10 |
| High-temperature resistance | 6.8 / 10 |
| Tensile strength | 5.5 / 10 |
| Cold formability | 9 / 10 |
| Machinability | 4.8 / 10 |
This page is guidance for selecting a grade, not a specification. Design to the governing standard and the mill certificate for the heat you are supplied.
The specifications and data on this site are provided for general information only. Verify any real-world project with a qualified metallurgist before relying on these figures. We take no responsibility for the use and application of this information.