Grade 304
Austenitic stainless · 1.4301, 18/8, AISI 304
The general-purpose austenitic stainless for food, dairy and fabrication work.
Data sheet
| Designations | AISI 304 / SAE 30304 · UNS S30400 · EN 1.4301 (X5CrNi18-10) |
|---|---|
| Standards | EN 10088-2, EN 10088-3, ASTM A240, ASTM A276 |
| Used for | food equipment, tanks, general fabrication |
Offered in
- Stainless steel sheet
- Stainless steel plate
- Stainless steel tread plate
- Stainless steel round bar
- Stainless steel flat bar
- Stainless steel square bar
- Stainless steel angle
- Stainless steel channel
- Stainless steel tube
- Stainless steel pipe
- Stainless steel fittings
- Stainless steel flanges
- Stainless steel hollow bar
- Stainless steel expanded metal
- Stainless steel mesh
- Stainless steel perforated sheet
- Stainless steel hex bar
Metallurgy
Reference data for Type 304 Stainless Steel (18/8), against ASTM A240, ASTM A276, EN 10088-2.
Elemental composition
X5CrNi18-10 to 1.4301
- Chromium 19,00%18,00–20,00%
- Nickel 9,25%8,00–10,50%
- Nitrogen 0,050%max 0,10%
- Carbon 0,040%max 0,080%
- Other additions 1,54%Mn, Si, P, S
- Iron 70,12%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 | 70,12% |
| Carbon C | max 0,080%cap | 0,040% |
| Chromium Cr | 18,00–20,00% | 19,00% |
| Nickel Ni | 8,00–10,50% | 9,25% |
| 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 | 515 MPa74,7 ksi |
| Yield strength, 0,2% offset | 205 MPa29,7 ksi |
| Elongation at break | 40% |
| Hardness | 170 HBW / 88 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 19,8
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
Moderate; susceptible to pitting and crevice corrosion in warm saline/marine environments (>100 mg/L chlorides).
Acidic and chemical media
Good resistance to oxidizing acids (e.g., nitric acid HNO3); poor resistance to reducing acids (e.g., sulfuric acid H2SO4, hydrochloric HCl).
Sensitisation and thermal behaviour
Susceptible to chromium carbide precipitation (Cr23C6) at grain boundaries when heated within 425°C–850°C (800°F–1560°F).
Welding
Excellent (autogenous, TIG, MIG, SMAW); post-weld annealing required in corrosive environments to prevent weld decay unless 304L is used.
Machining and cold forming
Machinability index 45% relative to AISI 1212. Exceptional; deep drawability, roll forming, and stretch forming due to high austenitic ductility (n-value ~0.45).
Where it is used
- Food processing equipment and beverage kegs
- Commercial kitchen sinks and cookware
- Architectural panels, facades, and handrails
- Chemical processing storage tanks and heat exchanger tubing
Food & Beverage · Architecture · Chemical Processing · Appliances
Performance scores in full
The same six scores the profile plots, as numbers.
| Property | 304 |
|---|---|
| Corrosion resistance | 7.5 / 10 |
| Weldability | 9 / 10 |
| High-temperature resistance | 7 / 10 |
| Tensile strength | 6 / 10 |
| Cold formability | 9 / 10 |
| Machinability | 5 / 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.