SAE-AISI 5140 (SCr440, G51400) Chromium Steel
SAE-AISI 5140 steel is an alloy steel formulated for primary forming into wrought products. 5140 is the designation in both the SAE and AISI systems for this material. G51400 is the UNS number.
The properties of SAE-AISI 5140 steel include four common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare SAE-AISI 5140 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
170 to 290
Elastic (Young's, Tensile) Modulus
190 GPa 27 x 106 psi
Elongation at Break
12 to 29 %
Fatigue Strength
220 to 570 MPa 32 to 83 x 103 psi
Poisson's Ratio
0.29
Shear Modulus
73 GPa 11 x 106 psi
Shear Strength
360 to 600 MPa 53 to 88 x 103 psi
Tensile Strength: Ultimate (UTS)
560 to 970 MPa 81 to 140 x 103 psi
Tensile Strength: Yield (Proof)
290 to 840 MPa 42 to 120 x 103 psi
Thermal Properties
Latent Heat of Fusion
250 J/g
Maximum Temperature: Mechanical
420 °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
45 W/m-K 26 BTU/h-ft-°F
Thermal Expansion
13 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
7.2 % IACS
Electrical Conductivity: Equal Weight (Specific)
8.3 % IACS
Otherwise Unclassified Properties
Base Metal Price
2.1 % relative
Density
7.8 g/cm3 490 lb/ft3
Embodied Carbon
1.4 kg CO2/kg material
Embodied Energy
19 MJ/kg 8.2 x 103 BTU/lb
Embodied Water
49 L/kg 5.9 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
76 to 180 MJ/m3
Resilience: Unit (Modulus of Resilience)
220 to 1880 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
20 to 34 points
Strength to Weight: Bending
19 to 28 points
Thermal Diffusivity
12 mm2/s
Thermal Shock Resistance
16 to 29 points
Alloy Composition
Among alloy steels, the composition of SAE-AISI 5140 steel is notable for containing comparatively high amounts of manganese (Mn) and chromium (Cr). Manganese is used to improve hardenability, hot workability, and surface quality. There is some loss of ductility and weldability, however. Chromium is used to improve corrosion resistance and most mechanical properties (particularly at higher temperatures).
| Fe | 97.3 to 98.1 | |
| Mn | 0.7 to 0.9 | |
| Cr | 0.7 to 0.9 | |
| C | 0.38 to 0.43 | |
| Si | 0.15 to 0.35 | |
| 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
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
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