Aluminum 6063-T6 vs. Stainless Steel 316

Compare Aluminum 6063-T6 vs. Stainless Steel 316 strength, stiffness, weight and thermal properties.

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Mechanical
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Yield strength	215MPasourcetypical, T6, 0.0625 in specimen	265MPasourcetypical (representative), annealed 1.0 mm sheet
Ultimate tensile strength	240MPasourcetypical, T6	583MPasourcetypical (representative), annealed 1.0 mm sheet
Elongation at break	12%sourcetypical, T6, in 4D	61%sourcetypical (representative), annealed, in 2 in. (51 mm)
Young's modulus (stiffness)	69GPasourcetypical	200GPasourcetypical, in tension
Density	2,700kg/m³sourcenominal, 20 °C	8,027kg/m³sourcetypical
Strength to weight	79.6kN·m/kg2.41x higher	33kN·m/kg
Stiffness to weight	25.6MN·m/kg3% higher	24.9MN·m/kg
Poisson's ratio	not sourced	0.3sourcedesign value (structural stainless steels)
Shear modulus	not sourced	76.9GPa
Bulk modulus	not sourced	167GPa
Speed of sound	5,055m/s	4,992m/s
Thermal
Thermal conductivity	201W/m·Ksourcetypical, T6, 20 °C	14.6W/m·Ksource20–100 °C
Thermal expansion	23.4µm/m·Ksourcetypical, mean 20-100 °C	16.5µm/m·Ksourcemean, 20–100 °C
100 mm part over a 50 °C swing	117µm growth	82.5µm growth42% less
Specific heat	901J/kg·Ksourcetypical, 20 °C (Hydro EN AW-6063)	450J/kg·Ksourceat 20 °C
Heats up and cools (diffusivity)	82.6mm²/s20.4x faster	4.04mm²/s
Thermal shock resistance	not sourced	821W/m
Melting point	615–655°Csourcemelting range	1,390–1,440°Csourcemelting range
Max service temperature	not sourced	871–899°Csourceoxidation (scaling) limit in air
Values for	6063-T6 extruded tube, Kaiser Aluminum Tube & Pipe Alloy 6063 Technical Data (Rev. 05/06), typical properties; specific heat from Hydro EN AW-6063 extruded-products datasheet (Rev.4, 03/2023).	ATI 316 (UNS S31600), annealed 1.0 mm sheet, ATI technical data sheet (2012); Poisson's ratio from the Nickel Institute/SCI structural stainless design manual

Every value links to the document that states it. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.

Questions

Is Aluminum 6063-T6 stronger than Stainless Steel 316?

Stainless Steel 316 is stronger: its yield strength is 265 MPa against 215 MPa for Aluminum 6063-T6 (23%).

Which is lighter, Aluminum 6063-T6 or Stainless Steel 316?

Aluminum 6063-T6 is lighter: 2,700 kg/m³ against 8,027 kg/m³ for Stainless Steel 316.

Which is stiffer, Aluminum 6063-T6 or Stainless Steel 316?

Stainless Steel 316 is stiffer: Young's modulus 200 GPa against 69 GPa for Aluminum 6063-T6, so the same part in Stainless Steel 316 deflects less under the same load.

Which is lighter for the same job, Aluminum 6063-T6 or Stainless Steel 316?

For the same stiffness or strength: Aluminum 6063-T6 is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate.

Part that must be	Aluminum 6063-T6	Stainless Steel 316
Stiff rod or tie (tension)	lighter	3% heavier
Stiff beam (bending)	lighter	1.75x heavier
Stiff panel or plate	lighter	2.09x heavier
Strong rod or tie	lighter	2.41x heavier
Strong beam	lighter	2.59x heavier
Strong panel or plate	lighter	2.68x heavier

For the same stiffness or strength, mass scales with density over stiffness (or strength) raised to a power set by how the part is loaded: 1 for a rod in tension, 1/2 for a beam in bending, 1/3 for a panel (the standard material-selection indices).

Which conducts heat better, Aluminum 6063-T6 or Stainless Steel 316?

Aluminum 6063-T6 conducts heat better: 201 W/m·K against 14.6 W/m·K for Stainless Steel 316.

Which expands less with temperature?

Stainless Steel 316 expands less: 16.5 µm/m·K against 23.4 µm/m·K for Aluminum 6063-T6.

Among 72 materials

Stiffness against density

Strength against density