ASTM A227 Class II Spring Steel
ASTM A227 class II is ASTM A227 spring steel in the cold worked (strain hardened) condition. The graph bars on the material properties cards below compare ASTM A227 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
640
Elastic (Young's, Tensile) Modulus
190 GPa 27 x 106 psi
Elongation at Break
12 %
Fatigue Strength
1160 MPa 170 x 103 psi
Poisson's Ratio
0.29
Shear Modulus
72 GPa 10 x 106 psi
Shear Strength
1330 MPa 190 x 103 psi
Tensile Strength: Ultimate (UTS)
2220 MPa 320 x 103 psi
Tensile Strength: Yield (Proof)
1850 MPa 270 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 2580 °F
Specific Heat Capacity
470 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
52 W/m-K 30 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)
260 MJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
79 points
Strength to Weight: Bending
48 points
Thermal Diffusivity
14 mm2/s
Thermal Shock Resistance
71 points
Alloy Composition
| Fe | 97.4 to 99.1 | |
| Mn | 0.3 to 1.3 | |
| C | 0.45 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 A227: Standard Specification for Steel Wire, Cold-Drawn 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