SAE-AISI 4024 (G40240) Molybdenum Steel
SAE-AISI 4024 steel is an alloy steel formulated for primary forming into wrought products. Cited properties are appropriate for the cold worked (strain hardened) condition. 4024 is the designation in both the SAE and AISI systems for this material. G40240 is the UNS number.
It has a moderately high thermal conductivity and a moderately low ductility among SAE-AISI wrought steels.
The graph bars on the material properties cards below compare SAE-AISI 4024 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
14 %
Fatigue Strength
320 MPa 46 x 103 psi
Poisson's Ratio
0.29
Shear Modulus
73 GPa 11 x 106 psi
Shear Strength
370 MPa 53 x 103 psi
Tensile Strength: Ultimate (UTS)
600 MPa 87 x 103 psi
Tensile Strength: Yield (Proof)
500 MPa 73 x 103 psi
Thermal Properties
Latent Heat of Fusion
250 J/g
Maximum Temperature: Mechanical
400 °C 760 °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
51 W/m-K 29 BTU/h-ft-°F
Thermal Expansion
13 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
7.1 % IACS
Electrical Conductivity: Equal Weight (Specific)
8.1 % IACS
Otherwise Unclassified Properties
Base Metal Price
2.1 % relative
Density
7.8 g/cm3 490 lb/ft3
Embodied Carbon
1.5 kg CO2/kg material
Embodied Energy
19 MJ/kg 8.3 x 103 BTU/lb
Embodied Water
47 L/kg 5.6 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
77 MJ/m3
Resilience: Unit (Modulus of Resilience)
670 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
14 mm2/s
Thermal Shock Resistance
18 points
Alloy Composition
Among alloy steels, the composition of SAE-AISI 4024 steel is notable for containing comparatively high amounts of manganese (Mn) and silicon (Si). Manganese is used to improve hardenability, hot workability, and surface quality. There is some loss of ductility and weldability, however. Silicon content is typically governed by metallurgical processing concerns, and not its effects on final material properties. However, it does have a modest strengthening effect.
| Fe | 98.1 to 98.7 | |
| Mn | 0.7 to 0.9 | |
| Si | 0.15 to 0.35 | |
| Mo | 0.2 to 0.3 | |
| C | 0.2 to 0.25 | |
| S | 0.035 to 0.050 | |
| P | 0 to 0.035 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
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