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SAE-AISI 4150 (G41500) Cr-Mo Steel

SAE-AISI 4150 steel is an alloy steel formulated for primary forming into wrought products. 4150 is the designation in both the SAE and AISI systems for this material. G41500 is the UNS number.

The properties of SAE-AISI 4150 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 4150 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

200 to 380

Elastic (Young's, Tensile) Modulus

190 GPa 27 x 106 psi

Elongation at Break

12 to 20 %

Fatigue Strength

260 to 780 MPa 38 to 110 x 103 psi

Poisson's Ratio

0.29

Shear Modulus

73 GPa 11 x 106 psi

Shear Strength

410 to 800 MPa 60 to 120 x 103 psi

Tensile Strength: Ultimate (UTS)

660 to 1310 MPa 96 to 190 x 103 psi

Tensile Strength: Yield (Proof)

380 to 1220 MPa 55 to 180 x 103 psi

Thermal Properties

Latent Heat of Fusion

250 J/g

Maximum Temperature: Mechanical

420 °C 790 °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

42 W/m-K 24 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

2.4 % relative

Density

7.8 g/cm3 490 lb/ft3

Embodied Carbon

1.5 kg CO2/kg material

Embodied Energy

20 MJ/kg 8.6 x 103 BTU/lb

Embodied Water

51 L/kg 6.1 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

82 to 180 MJ/m3

Resilience: Unit (Modulus of Resilience)

380 to 3930 kJ/m3

Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

24 points

Strength to Weight: Axial

24 to 47 points

Strength to Weight: Bending

22 to 34 points

Thermal Diffusivity

11 mm2/s

Thermal Shock Resistance

19 to 39 points

Alloy Composition

Among alloy steels, the composition of SAE-AISI 4150 steel is notable for containing comparatively high amounts of chromium (Cr) and manganese (Mn). Chromium is used to improve corrosion resistance and most mechanical properties (particularly at higher temperatures). Manganese is used to improve hardenability, hot workability, and surface quality. There is some loss of ductility and weldability, however.

Iron (Fe) 96.7 to 97.7
Chromium (Cr) 0.8 to 1.1
Manganese (Mn) 0.75 to 1.0
Carbon (C) 0.48 to 0.53
Silicon (Si) 0.15 to 0.35
Molybdenum (Mo) 0.15 to 0.25
Sulfur (S) 0 to 0.040
Phosphorus (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