SAE-AISI 4028 (G40280) Molybdenum Steel
SAE-AISI 4028 steel is an alloy steel formulated for primary forming into wrought products. 4028 is the designation in both the SAE and AISI systems for this material. G40280 is the UNS number.
The properties of SAE-AISI 4028 steel include two common variations. This page shows summary ranges across both of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare SAE-AISI 4028 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
150 to 190
Elastic (Young's, Tensile) Modulus
190 GPa 27 x 106 psi
Elongation at Break
14 to 23 %
Fatigue Strength
180 to 330 MPa 27 to 48 x 103 psi
Poisson's Ratio
0.29
Shear Modulus
73 GPa 11 x 106 psi
Shear Strength
310 to 380 MPa 45 to 55 x 103 psi
Tensile Strength: Ultimate (UTS)
490 to 630 MPa 71 to 91 x 103 psi
Tensile Strength: Yield (Proof)
260 to 520 MPa 37 to 76 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
49 W/m-K 28 BTU/h-ft-°F
Thermal Expansion
12 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)
81 to 95 MJ/m3
Resilience: Unit (Modulus of Resilience)
180 to 720 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
17 to 22 points
Strength to Weight: Bending
18 to 21 points
Thermal Diffusivity
13 mm2/s
Thermal Shock Resistance
16 to 20 points
Alloy Composition
Among alloy steels, the composition of SAE-AISI 4028 steel is notable for containing comparatively high amounts of manganese (Mn) and carbon (C). Manganese is used to improve hardenability, hot workability, and surface quality. There is some loss of ductility and weldability, however. Carbon is used to increase strength at the cost of a decrease in formability.
| Fe | 98.1 to 98.7 | |
| Mn | 0.7 to 0.9 | |
| C | 0.25 to 0.3 | |
| Si | 0.15 to 0.35 | |
| Mo | 0.2 to 0.3 | |
| 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 A752: Standard Specification for General Requirements for Wire Rods and Coarse Round Wire, Alloy Steel
ASTM A322: Standard Specification for Steel Bars, Alloy, Standard Grades
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