Cold Finished 8645 Ni-Cr-Mo Steel
Cold finished SAE-AISI 8645 is SAE-AISI 8645 steel in the cold worked (strain hardened) condition. The graph bars on the material properties cards below compare cold finished SAE-AISI 8645 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
350 MPa 51 x 103 psi
Poisson's Ratio
0.29
Shear Modulus
73 GPa 11 x 106 psi
Shear Strength
400 MPa 58 x 103 psi
Tensile Strength: Ultimate (UTS)
670 MPa 97 x 103 psi
Tensile Strength: Yield (Proof)
560 MPa 81 x 103 psi
Thermal Properties
Latent Heat of Fusion
250 J/g
Maximum Temperature: Mechanical
410 °C 780 °F
Melting Completion (Liquidus)
1460 °C 2650 °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 8.7 x 103 BTU/lb
Embodied Water
50 L/kg 6.0 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
77 MJ/m3
Resilience: Unit (Modulus of Resilience)
840 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
24 points
Strength to Weight: Bending
22 points
Thermal Diffusivity
10 mm2/s
Thermal Shock Resistance
20 points
Alloy Composition
| Fe | 96.5 to 97.7 | |
| Mn | 0.75 to 1.0 | |
| Ni | 0.4 to 0.7 | |
| Cr | 0.4 to 0.6 | |
| C | 0.43 to 0.48 | |
| 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
Further Reading
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
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