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SAE-AISI 4027 (G40270) Molybdenum Steel

SAE-AISI 4027 steel is an alloy steel formulated for primary forming into wrought products. Cited properties are appropriate for the annealed condition. 4027 is the designation in both the SAE and AISI systems for this material. G40270 is the UNS number.

The graph bars on the material properties cards below compare SAE-AISI 4027 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

Elastic (Young's, Tensile) Modulus

190 GPa 27 x 106 psi

Elongation at Break

23 %

Fatigue Strength

190 MPa 27 x 103 psi

Poisson's Ratio

0.29

Shear Modulus

73 GPa 11 x 106 psi

Shear Strength

320 MPa 46 x 103 psi

Tensile Strength: Ultimate (UTS)

500 MPa 73 x 103 psi

Tensile Strength: Yield (Proof)

260 MPa 38 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)

97 MJ/m3

Resilience: Unit (Modulus of Resilience)

190 kJ/m3

Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

24 points

Strength to Weight: Axial

18 points

Strength to Weight: Bending

18 points

Thermal Diffusivity

13 mm2/s

Thermal Shock Resistance

16 points

Alloy Composition

Among alloy steels, the composition of SAE-AISI 4027 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.

Iron (Fe) 98.1 to 98.7
Manganese (Mn) 0.7 to 0.9
Carbon (C) 0.25 to 0.3
Silicon (Si) 0.15 to 0.35
Molybdenum (Mo) 0.2 to 0.3
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

CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015

Steels: Processing, Structure, and Performance, 2nd ed., George Krauss, 2015