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SAE-AISI 1040 (S40C, G10400) Carbon Steel

SAE-AISI 1040 steel is a carbon (non-alloy) steel formulated for primary forming into wrought products. 1040 is the designation in both the SAE and AISI systems for this material. G10400 is the UNS number.

The properties of SAE-AISI 1040 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 1040 steel to: wrought carbon or non-alloy 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

160 to 180

Elastic (Young's, Tensile) Modulus

190 GPa 27 x 106 psi

Elongation at Break

13 to 20 %

Fatigue Strength

220 to 340 MPa 31 to 49 x 103 psi

Poisson's Ratio


Reduction in Area

40 to 45 %

Shear Modulus

73 GPa 11 x 106 psi

Shear Strength

350 to 390 MPa 51 to 56 x 103 psi

Tensile Strength: Ultimate (UTS)

570 to 640 MPa 82 to 93 x 103 psi

Tensile Strength: Yield (Proof)

320 to 530 MPa 46 to 77 x 103 psi

Thermal Properties

Latent Heat of Fusion

250 J/g

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

12 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

7.0 % IACS

Electrical Conductivity: Equal Weight (Specific)

8.0 % IACS

Otherwise Unclassified Properties

Base Metal Price

1.8 % relative


7.8 g/cm3 490 lb/ft3

Embodied Carbon

1.4 kg CO2/kg material

Embodied Energy

18 MJ/kg 7.9 x 103 BTU/lb

Embodied Water

46 L/kg 5.5 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

79 to 96 MJ/m3

Resilience: Unit (Modulus of Resilience)

270 to 760 kJ/m3

Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

24 points

Strength to Weight: Axial

20 to 23 points

Strength to Weight: Bending

19 to 21 points

Thermal Diffusivity

14 m2/s

Thermal Shock Resistance

18 to 20 points

Alloy Composition

Iron (Fe) 98.6 to 99.03
Manganese (Mn) 0.6 to 0.9
Carbon (C) 0.37 to 0.44
Sulfur (S) 0 to 0.050
Phosphorus (P) 0 to 0.040

All values are % weight. Ranges represent what is permitted under applicable standards.

Followup Questions

Similar Alloys

Further Reading

Cold-Formed Steel Structures to the AISI Specification, Gregory J. Hancock et al., 2001

ASTM A29: Standard Specification for Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements for

Carbon Steel Handbook, D. Gandy, 2007

ASM Specialty Handbook: Carbon and Alloy Steels, J. R. Davis (editor), 1996

Ferrous Materials: Steel and Cast Iron, Hans Berns and Werner Theisen, 2008

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