ASTM A229 Class II Spring Steel
ASTM A229 class II is ASTM A229 spring steel in the quenched and tempered condition. The graph bars on the material properties cards below compare ASTM A229 class II 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
550
Elastic (Young's, Tensile) Modulus
190 GPa 27 x 106 psi
Elongation at Break
14 %
Fatigue Strength
790 MPa 110 x 103 psi
Poisson's Ratio
0.29
Shear Modulus
72 GPa 10 x 106 psi
Shear Strength
1140 MPa 170 x 103 psi
Tensile Strength: Ultimate (UTS)
1890 MPa 270 x 103 psi
Tensile Strength: Yield (Proof)
1230 MPa 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)
230 MJ/m3
Resilience: Unit (Modulus of Resilience)
4080 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
67 points
Strength to Weight: Bending
43 points
Thermal Diffusivity
14 mm2/s
Thermal Shock Resistance
60 points
Alloy Composition
| Fe | 97.5 to 99 | |
| Mn | 0.3 to 1.2 | |
| C | 0.55 to 0.85 | |
| Si | 0.15 to 0.35 | |
| S | 0 to 0.050 | |
| P | 0 to 0.040 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
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