# ASTM A227 Class I Spring Steel

ASTM A227 class I 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 I 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

500

Elastic (Young's, Tensile) Modulus

190 *GPa* 27 *x 10 ^{6} psi*

Elongation at Break

12 *%*

Fatigue Strength

900 *MPa* 130 *x 10 ^{3} psi*

Poisson's Ratio

0.29

Shear Modulus

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

Shear Strength

1030 *MPa* 150 *x 10 ^{3} psi*

Tensile Strength: Ultimate (UTS)

1720 *MPa* 250 *x 10 ^{3} psi*

Tensile Strength: Yield (Proof)

1430 *MPa* 210 *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)

200 *MJ/m ^{3}*

Resilience: Unit (Modulus of Resilience)

5470 *kJ/m ^{3}*

Stiffness to Weight: Axial

13 *points*

Stiffness to Weight: Bending

24 *points*

Strength to Weight: Axial

61 *points*

Strength to Weight: Bending

41 *points*

Thermal Diffusivity

14 *mm ^{2}/s*

Thermal Shock Resistance

55 *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