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SAE-AISI 8115 (G81150) Ni-Cr-Mo Steel

SAE-AISI 8115 steel is an alloy steel formulated for primary forming into wrought products. Cited properties are appropriate for the cold worked (strain hardened) condition. 8115 is the designation in both the SAE and AISI systems for this material. G81150 is the UNS number.

It has a moderately low ductility among the SAE-AISI wrought steels in the database.

The graph bars on the material properties cards below compare SAE-AISI 8115 steel 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

180

Elastic (Young's, Tensile) Modulus

190 GPa 27 x 106 psi

Elongation at Break

15 %

Fatigue Strength

320 MPa 47 x 103 psi

Poisson's Ratio

0.29

Shear Modulus

73 GPa 11 x 106 psi

Shear Strength

370 MPa 54 x 103 psi

Tensile Strength: Ultimate (UTS)

610 MPa 88 x 103 psi

Tensile Strength: Yield (Proof)

500 MPa 72 x 103 psi

Thermal Properties

Latent Heat of Fusion

250 J/g

Maximum Temperature: Mechanical

410 °C 770 °F

Melting Completion (Liquidus)

1460 °C 2660 °F

Melting Onset (Solidus)

1420 °C 2590 °F

Specific Heat Capacity

470 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

7.2 % IACS

Electrical Conductivity: Equal Weight (Specific)

8.2 % IACS

Otherwise Unclassified Properties

Base Metal Price

2.3 % relative

Density

7.8 g/cm3 490 lb/ft3

Embodied Carbon

1.5 kg CO2/kg material

Embodied Energy

19 MJ/kg 8.4 x 103 BTU/lb

Embodied Water

49 L/kg 5.8 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

86 MJ/m3

Resilience: Unit (Modulus of Resilience)

660 kJ/m3

Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

24 points

Strength to Weight: Axial

21 points

Strength to Weight: Bending

20 points

Thermal Diffusivity

12 mm2/s

Thermal Shock Resistance

19 points

Alloy Composition

Among alloy steels, the composition of SAE-AISI 8115 steel is notable for including nickel (Ni). Nickel is used to improve mechanical properties, and to make the alloy easier to heat treat.

Iron (Fe) 97.4 to 98.4
Manganese (Mn) 0.7 to 0.9
Chromium (Cr) 0.3 to 0.5
Nickel (Ni) 0.2 to 0.4
Silicon (Si) 0.15 to 0.35
Carbon (C) 0.13 to 0.18
Molybdenum (Mo) 0.080 to 0.15
Sulfur (S) 0 to 0.040
Phosphorus (P) 0 to 0.035

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

Followup Questions

Similar Alloys

Further Reading

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

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

CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015

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