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SAE-AISI 8660 (G86600) Ni-Cr-Mo Steel

SAE-AISI 8660 steel is an alloy steel formulated for primary forming into wrought products. Cited properties are appropriate for the cold worked (strain hardened) condition. 8660 is the designation in both the SAE and AISI systems for this material. G86600 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 8660 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

200

Elastic (Young's, Tensile) Modulus

190 GPa 27 x 106 psi

Elongation at Break

12 %

Fatigue Strength

340 MPa 50 x 103 psi

Poisson's Ratio

0.29

Shear Modulus

73 GPa 11 x 106 psi

Shear Strength

390 MPa 57 x 103 psi

Tensile Strength: Ultimate (UTS)

660 MPa 95 x 103 psi

Tensile Strength: Yield (Proof)

550 MPa 80 x 103 psi

Thermal Properties

Latent Heat of Fusion

250 J/g

Maximum Temperature: Mechanical

410 °C 780 °F

Melting Completion (Liquidus)

1450 °C 2650 °F

Melting Onset (Solidus)

1410 °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 5.9 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

73 MJ/m3

Resilience: Unit (Modulus of Resilience)

800 kJ/m3

Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

24 points

Strength to Weight: Axial

23 points

Strength to Weight: Bending

21 points

Thermal Diffusivity

10 mm2/s

Thermal Shock Resistance

19 points

Alloy Composition

Among alloy steels, the composition of SAE-AISI 8660 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) 96.4 to 97.6
Manganese (Mn) 0.75 to 1.0
Carbon (C) 0.56 to 0.64
Nickel (Ni) 0.4 to 0.7
Chromium (Cr) 0.4 to 0.6
Silicon (Si) 0.15 to 0.35
Molybdenum (Mo) 0.15 to 0.25
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

Properties and Selection: Irons, Steels and High Performance Alloys, ASM Handbook vol. 1, ASM International, 1993

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