# Quenched and Tempered (+QT) 1.8151 Steel

EN 1.8151 +QT steel is EN 1.8151 steel in the quenched and tempered condition. It has the second highest strength compared to the other variants of EN 1.8151 steel. The graph bars on the material properties cards below compare EN 1.8151 +QT steel to: EN wrought 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

540

Elastic (Young's, Tensile) Modulus

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

Elongation at Break

8.0 *%*

Fatigue Strength

1050 *MPa* 150 *x 10 ^{3} psi*

Impact Strength: U-Notched Charpy

15 *J* 11 *ft-lb*

Poisson's Ratio

0.29

Reduction in Area

45 *%*

Shear Modulus

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

Shear Strength

1060 *MPa* 150 *x 10 ^{3} psi*

Tensile Strength: Ultimate (UTS)

1790 *MPa* 260 *x 10 ^{3} psi*

Tensile Strength: Yield (Proof)

1770 *MPa* 260 *x 10 ^{3} psi*

## Thermal Properties

Latent Heat of Fusion

270 *J/g*

Maximum Temperature: Mechanical

410 *°C* 770 *°F*

Melting Completion (Liquidus)

1440 *°C* 2630 *°F*

Melting Onset (Solidus)

1400 *°C* 2550 *°F*

Specific Heat Capacity

480 *J/kg-K* 0.11 *BTU/lb-°F*

Thermal Conductivity

50 *W/m-K* 29 *BTU/h-ft-°F*

Thermal Expansion

13 *µm/m-K*

## Electrical Properties

Electrical Conductivity: Equal Volume

7.4 *% IACS*

Electrical Conductivity: Equal Weight (Specific)

8.6 *% IACS*

## Otherwise Unclassified Properties

Base Metal Price

2.2 *% relative*

Density

7.7 *g/cm ^{3}* 480

*lb/ft*

^{3}Embodied Carbon

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

Embodied Energy

25 *MJ/kg* 11 *x 10 ^{3} BTU/lb*

Embodied Water

49 *L/kg* 5.9 *gal/lb*

## Common Calculations

Resilience: Ultimate (Unit Rupture Work)

140 *MJ/m ^{3}*

Stiffness to Weight: Axial

13 *points*

Stiffness to Weight: Bending

25 *points*

Strength to Weight: Axial

64 *points*

Strength to Weight: Bending

42 *points*

Thermal Diffusivity

14 *mm ^{2}/s*

Thermal Shock Resistance

54 *points*

## Alloy Composition

Fe | 95.9 to 97.2 | |

Si | 1.3 to 1.7 | |

Mn | 0.6 to 0.9 | |

Cr | 0.4 to 0.8 | |

C | 0.4 to 0.5 | |

V | 0.1 to 0.2 | |

P | 0 to 0.025 | |

S | 0 to 0.025 |

All values are % weight. Ranges represent what is permitted under applicable standards.

## Followup Questions

## Further Reading

EN 10089: Hot rolled steels for quenched and tempered springs - Technical delivery conditions

Manufacture and Uses of Alloy Steels, Henry D. Hibbard, 2005

Ferrous Materials: Steel and Cast Iron, Hans Berns and Werner Theisen, 2008

Steels: Processing, Structure, and Performance, 2nd ed., George Krauss, 2015