SAE-AISI O6 (T31506) Oil-Hardening Steel

SAE-AISI O6 steel is a tool steel. O6 is the designation in both the SAE and AISI systems for this material. T31506 is the UNS number.

The properties of SAE-AISI O6 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 SAE-AISI O6 steel to: tool 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.

Annealed O6 Tool Steel Hardened O6 Tool Steel

Mechanical Properties

Elastic (Young's, Tensile) Modulus

180 GPa 27 x 10⁶ psi

Poisson's Ratio

0.29

Shear Modulus

71 GPa 10 x 10⁶ psi

Tensile Strength: Ultimate (UTS)

670 to 2070 MPa 97 to 300 x 10³ psi

Thermal Properties

Latent Heat of Fusion

260 J/g

Melting Completion (Liquidus)

1430 °C 2610 °F

Melting Onset (Solidus)

1390 °C 2540 °F

Specific Heat Capacity

480 J/kg-K 0.11 BTU/lb-°F

Thermal Conductivity

43 W/m-K 25 BTU/h-ft-°F

Thermal Expansion

12 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

7.4 % IACS

Electrical Conductivity: Equal Weight (Specific)

8.6 % IACS

Otherwise Unclassified Properties

Base Metal Price

2.3 % relative

Density

7.7 g/cm³ 480 lb/ft³

Embodied Carbon

1.5 kg CO₂/kg material

Embodied Energy

21 MJ/kg 8.8 x 10³ BTU/lb

Embodied Water

47 L/kg 5.6 gal/lb

Common Calculations

Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

25 points

Strength to Weight: Axial

24 to 74 points

Strength to Weight: Bending

22 to 47 points

Thermal Diffusivity

12 mm²/s

Thermal Shock Resistance

22 to 69 points

Alloy Composition

Iron (Fe)Fe		94.6 to 97.7
Carbon (C)C		1.3 to 1.6
Silicon (Si)Si		0.55 to 1.5
Manganese (Mn)Mn		0.3 to 1.1
Molybdenum (Mo)Mo		0.2 to 0.3
Chromium (Cr)Cr		0 to 0.3
Nickel (Ni)Ni		0 to 0.3
Copper (Cu)Cu		0 to 0.25
Phosphorus (P)P		0 to 0.030
Sulfur (S)S		0 to 0.030