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Annealed 8740 Ni-Cr-Mo Steel

Annealed SAE-AISI 8740 is SAE-AISI 8740 steel in the annealed condition. The graph bars on the material properties cards below compare annealed SAE-AISI 8740 to: SAE-AISI wrought 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

Elastic (Young's, Tensile) Modulus

190 GPa 27 x 106 psi

Elongation at Break

23 %

Fatigue Strength

270 MPa 40 x 103 psi

Poisson's Ratio

0.29

Shear Modulus

73 GPa 11 x 106 psi

Shear Strength

370 MPa 53 x 103 psi

Tensile Strength: Ultimate (UTS)

580 MPa 84 x 103 psi

Tensile Strength: Yield (Proof)

380 MPa 55 x 103 psi

Thermal Properties

Latent Heat of Fusion

250 J/g

Maximum Temperature: Mechanical

410 °C 780 °F

Melting Completion (Liquidus)

1460 °C 2660 °F

Melting Onset (Solidus)

1420 °C 2580 °F

Specific Heat Capacity

470 J/kg-K 0.11 BTU/lb-°F

Thermal Conductivity

39 W/m-K 22 BTU/h-ft-°F

Thermal Expansion

13 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

7.3 % IACS

Electrical Conductivity: Equal Weight (Specific)

8.4 % IACS

Otherwise Unclassified Properties

Base Metal Price

2.6 % relative

Density

7.8 g/cm3 490 lb/ft3

Embodied Carbon

1.5 kg CO2/kg material

Embodied Energy

20 MJ/kg 8.8 x 103 BTU/lb

Embodied Water

50 L/kg 6.0 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

120 MJ/m3

Resilience: Unit (Modulus of Resilience)

390 kJ/m3

Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

24 points

Strength to Weight: Axial

20 points

Strength to Weight: Bending

20 points

Thermal Diffusivity

10 mm2/s

Thermal Shock Resistance

17 points

Alloy Composition

Iron (Fe)Fe 96.5 to 97.7
Manganese (Mn)Mn 0.75 to 1.0
Nickel (Ni)Ni 0.4 to 0.7
Chromium (Cr)Cr 0.4 to 0.6
Carbon (C)C 0.38 to 0.43
Silicon (Si)Si 0.15 to 0.35
Molybdenum (Mo)Mo 0.2 to 0.3
Sulfur (S)S 0 to 0.040
Phosphorus (P)P 0 to 0.035

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

Followup Questions

How are the material properties defined?How do I compare this exact variant to another material?

Further Reading

ASTM A752: Standard Specification for General Requirements for Wire Rods and Coarse Round Wire, Alloy Steel

ASTM A322: Standard Specification for Steel Bars, Alloy, Standard Grades

ASM Specialty Handbook: Carbon and Alloy Steels, J. R. Davis (editor), 1996

Manufacture and Uses of Alloy Steels, Henry D. Hibbard, 2005

Steels: Processing, Structure, and Performance, 2nd ed., George Krauss, 2015