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ASTM A229 Oil-Tempered Spring Steel

ASTM A229 spring steel is a carbon (non-alloy) steel formulated for primary forming into wrought products. It can have a very high tensile strength and has a moderately low ductility among wrought carbon or non-alloy steels.

The properties of ASTM A229 spring 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 ASTM A229 spring 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

490 to 550

Elastic (Young's, Tensile) Modulus

190 GPa 27 x 106 psi

Elongation at Break

14 %

Fatigue Strength

710 to 790 MPa 100 to 110 x 103 psi

Poisson's Ratio

0.29

Shear Modulus

72 GPa 10 x 106 psi

Shear Strength

1020 to 1140 MPa 150 to 170 x 103 psi

Tensile Strength: Ultimate (UTS)

1690 to 1890 MPa 240 to 270 x 103 psi

Tensile Strength: Yield (Proof)

1100 to 1230 MPa 160 to 180 x 103 psi

Thermal Properties

Latent Heat of Fusion

250 J/g

Maximum Temperature: Mechanical

400 °C 750 °F

Melting Completion (Liquidus)

1450 °C 2650 °F

Melting Onset (Solidus)

1410 °C 2570 °F

Specific Heat Capacity

470 J/kg-K 0.11 BTU/lb-°F

Thermal Conductivity

50 W/m-K 29 BTU/h-ft-°F

Thermal Expansion

12 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

1.8 % relative

Density

7.8 g/cm3 490 lb/ft3

Embodied Carbon

1.4 kg CO2/kg material

Embodied Energy

19 MJ/kg 8.0 x 103 BTU/lb

Embodied Water

46 L/kg 5.5 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

200 to 230 MJ/m3

Resilience: Unit (Modulus of Resilience)

3260 to 4080 kJ/m3

Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

24 points

Strength to Weight: Axial

60 to 67 points

Strength to Weight: Bending

40 to 43 points

Thermal Diffusivity

14 mm2/s

Thermal Shock Resistance

54 to 60 points

Alloy Composition

Iron (Fe) 97.5 to 99
Manganese (Mn) 0.3 to 1.2
Carbon (C) 0.55 to 0.85
Silicon (Si) 0.15 to 0.35
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

ASTM A229: Standard Specification for Steel Wire, Oil-Tempered for Mechanical Springs

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