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.
| Fe | 96.4 to 97.6 | |
| Mn | 0.75 to 1.0 | |
| C | 0.56 to 0.64 | |
| Ni | 0.4 to 0.7 | |
| Cr | 0.4 to 0.6 | |
| Si | 0.15 to 0.35 | |
| Mo | 0.15 to 0.25 | |
| S | 0 to 0.040 | |
| 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