# 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 10 ^{6} psi*

Elongation at Break

12 *%*

Fatigue Strength

1160 *MPa* 170 *x 10 ^{3} psi*

Poisson's Ratio

0.29

Shear Modulus

72 *GPa* 10 *x 10 ^{6} psi*

Shear Strength

1330 *MPa* 190 *x 10 ^{3} psi*

Tensile Strength: Ultimate (UTS)

2220 *MPa* 320 *x 10 ^{3} psi*

Tensile Strength: Yield (Proof)

1850 *MPa* 270 *x 10 ^{3} 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/cm ^{3}* 490

*lb/ft*

^{3}Embodied Carbon

1.4 *kg CO _{2}/kg material*

Embodied Energy

19 *MJ/kg* 8.0 *x 10 ^{3} BTU/lb*

Embodied Water

46 *L/kg* 5.5 *gal/lb*

## Common Calculations

Resilience: Ultimate (Unit Rupture Work)

260 *MJ/m ^{3}*

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 *mm ^{2}/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