AISI 304 (1.4301, S30400) Stainless Steel

AISI 304 stainless steel is an alloy of iron, further classified as an austenitic stainless steel. 304 is the AISI designation for this material. 1.4301 is the EN numeric designation. S30400 is the UNS number. Additionally, the EN chemical designation is X5CrNi18-10. And the British Standard (BS) designation is 304S15.

It has five common variants, each represented as a separate material.

Material Properties

Base Metal Price25 % rel

Calomel Potential-80 mV

Density7.8 g/cm3 (490 lb/ft3)

Elastic (Young's, Tensile) Modulus200 GPa (29 x 106 psi)

Electrical Conductivity13 % IACS

Electrical Resistivity Order of Magnitude-7 10x Ω-m

Elongation at Break8.1 to 42 %

Melting Onset (Solidus)1400 °C (2550 °F)

Poisson's Ratio0.28

PREN (Pitting Resistance)19

Specific Heat Capacity500 J/kg-K

Strength to Weight Ratio76 to 150 kN-m/kg

Tensile Strength: Ultimate (UTS)590 to 1190 MPa (86 to 170 x 103 psi)

Tensile Strength: Yield (Proof)240 to 870 MPa (35 to 130 x 103 psi)

Thermal Conductivity16 W/m-K

Thermal Diffusivity4.1

Thermal Expansion17 µm/m-K

Alloy Composition

Iron (Fe)66.5 to 74 %

Chromium (Cr)18 to 20 %

Nickel (Ni)8.0 to 10.5 %

Manganese (Mn)0 to 2.0 %

Silicon (Si)0 to 0.75 %

Nitrogen (N)0 to 0.1 %

Carbon (C)0 to 0.080 %

Phosphorus (P)0 to 0.045 %

Sulfur (S)0 to 0.030 %

Further Reading

ASTM A240: Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications

ASTM A276: Standard Specification for Stainless Steel Bars and Shapes

ASTM A473: Standard Specification for Stainless Steel Forgings

ASTM A479: Standard Specification for Stainless Steel Bars and Shapes for Use in Boilers and Other Pressure Vessels

ASTM A666: Standard Specification for Annealed or Cold-Worked Austenitic Stainless Steel Sheet, Strip, Plate, and Flat Bar

ASTM A959: Standard Guide for Specifying Harmonized Standard Grade Compositions for Wrought Stainless Steels

EN 10088-2: Stainless steels - Technical delivery conditions for sheet/plate and strip of corrosion resisting steels for general purposes