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AISI 303 (S30300) Stainless Steel

AISI 303 stainless steel is an austenitic stainless steel formulated for primary forming into wrought products. 303 is the AISI designation for this material. S30300 is the UNS number. Additionally, the British Standard (BS) designation is 303S21.

It has a moderately low embodied energy among the wrought austenitic stainless steels in the database.

The properties of AISI 303 stainless steel include two common variations. This page shows summary ranges across both of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare AISI 303 stainless steel to: wrought austenitic stainless steels (top), all iron alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.

Mechanical Properties

Brinell Hardness

170 to 210

Elastic (Young's, Tensile) Modulus

200 GPa 28 x 106 psi

Elongation at Break

40 to 51 %

Fatigue Strength

230 to 360 MPa 33 to 52 x 103 psi

Poisson's Ratio

0.28

Shear Modulus

77 GPa 11 x 106 psi

Shear Strength

430 to 470 MPa 62 to 69 x 103 psi

Tensile Strength: Ultimate (UTS)

600 to 690 MPa 87 to 100 x 103 psi

Tensile Strength: Yield (Proof)

230 to 420 MPa 34 to 60 x 103 psi

Thermal Properties

Latent Heat of Fusion

290 J/g

Maximum Temperature: Corrosion

410 °C 780 °F

Maximum Temperature: Mechanical

930 °C 1700 °F

Melting Completion (Liquidus)

1450 °C 2640 °F

Melting Onset (Solidus)

1400 °C 2550 °F

Specific Heat Capacity

480 J/kg-K 0.11 BTU/lb-°F

Thermal Conductivity

16 W/m-K 9.4 BTU/h-ft-°F

Thermal Expansion

17 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

2.4 % IACS

Electrical Conductivity: Equal Weight (Specific)

2.8 % IACS

Otherwise Unclassified Properties

Base Metal Price

15 % relative

Calomel Potential

-80 mV

Density

7.8 g/cm3 490 lb/ft3

Embodied Carbon

3.0 kg CO2/kg material

Embodied Energy

42 MJ/kg 18 x 103 BTU/lb

Embodied Water

140 L/kg 17 gal/lb

Common Calculations

PREN (Pitting Resistance)

18

Resilience: Ultimate (Unit Rupture Work)

240 MJ/m3

Resilience: Unit (Modulus of Resilience)

140 to 440 kJ/m3

Stiffness to Weight: Axial

14 points

Stiffness to Weight: Bending

25 points

Strength to Weight: Axial

21 to 25 points

Strength to Weight: Bending

20 to 22 points

Thermal Diffusivity

4.4 mm2/s

Thermal Shock Resistance

13 to 15 points

Alloy Composition

Among wrought stainless steels, the composition of AISI 303 stainless steel is notable for containing comparatively high amounts of nickel (Ni) and chromium (Cr). Nickel is primarily used to achieve a specific microstructure. In addition, it has a beneficial effect on mechanical properties and certain types of corrosion. Chromium is the defining alloying element of stainless steel. Higher chromium content imparts additional corrosion resistance.

Iron (Fe)Fe 67.3 to 74.9
Chromium (Cr)Cr 17 to 19
Nickel (Ni)Ni 8.0 to 10
Manganese (Mn)Mn 0 to 2.0
Silicon (Si)Si 0 to 1.0
Sulfur (S)S 0.15 to 0.35
Phosphorus (P)P 0 to 0.2
Carbon (C)C 0 to 0.15

All values are % weight. Ranges represent what is permitted under applicable standards.

Followup Questions

Similar Alloys

Further Reading

ASTM A895: Standard Specification for Free-Machining Stainless Steel Plate, Sheet, and Strip

ASTM A473: Standard Specification for Stainless Steel Forgings

ASTM A276: Standard Specification for Stainless Steel Bars and Shapes

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

Corrosion of Austenitic Stainless Steels: Mechanism, Mitigation and Monitoring, H. S. Khatak and B. Raj (editors), 2002

Austenitic Stainless Steels: Microstructure and Mechanical Properties, P. Marshall, 1984

ASM Specialty Handbook: Stainless Steels, J. R. Davis (editor), 1994

Advances in Stainless Steels, Baldev Raj et al. (editors), 2010