Cold Finished 8740 Ni-Cr-Mo Steel
Cold finished SAE-AISI 8740 is SAE-AISI 8740 steel in the cold worked (strain hardened) condition. The graph bars on the material properties cards below compare cold finished 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
200
Elastic (Young's, Tensile) Modulus
190 GPa 27 x 106 psi
Elongation at Break
11 %
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)
570 MPa 82 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)
71 MJ/m3
Resilience: Unit (Modulus of Resilience)
850 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 | 0.38 to 0.43 | |
| Si | 0.15 to 0.35 | |
| Mo | 0.2 to 0.3 | |
| 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
Steels: Processing, Structure, and Performance, 2nd ed., George Krauss, 2015