# SAE-AISI 9255 (G92550) Silicon Steel

SAE-AISI 9255 steel is an alloy steel formulated for primary forming into wrought products. Cited properties are appropriate for the annealed condition. 9255 is the designation in both the SAE and AISI systems for this material. G92550 is the UNS number.

It has a moderately low base cost and a moderately high tensile strength among SAE-AISI wrought steels.

The graph bars on the material properties cards below compare SAE-AISI 9255 steel to: SAE-AISI wrought 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

200

Elastic (Young's, Tensile) Modulus

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

Elongation at Break

21 *%*

Fatigue Strength

270 *MPa* 39 *x 10 ^{3} psi*

Poisson's Ratio

0.29

Shear Modulus

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

Shear Strength

430 *MPa* 62 *x 10 ^{3} psi*

Tensile Strength: Ultimate (UTS)

680 *MPa* 98 *x 10 ^{3} psi*

Tensile Strength: Yield (Proof)

390 *MPa* 56 *x 10 ^{3} psi*

## Thermal Properties

Latent Heat of Fusion

280 *J/g*

Maximum Temperature: Mechanical

400 *°C* 750 *°F*

Melting Completion (Liquidus)

1430 *°C* 2610 *°F*

Melting Onset (Solidus)

1390 *°C* 2540 *°F*

Specific Heat Capacity

480 *J/kg-K* 0.11 *BTU/lb-°F*

Thermal Conductivity

46 *W/m-K* 27 *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

2.0 *% relative*

Density

7.7 *g/cm ^{3}* 480

*lb/ft*

^{3}Embodied Carbon

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

Embodied Energy

20 *MJ/kg* 8.4 *x 10 ^{3} BTU/lb*

Embodied Water

46 *L/kg* 5.4 *gal/lb*

## Common Calculations

Resilience: Ultimate (Unit Rupture Work)

120 *MJ/m ^{3}*

Resilience: Unit (Modulus of Resilience)

400 *kJ/m ^{3}*

Stiffness to Weight: Axial

13 *points*

Stiffness to Weight: Bending

25 *points*

Strength to Weight: Axial

24 *points*

Strength to Weight: Bending

22 *points*

Thermal Diffusivity

13 *mm ^{2}/s*

Thermal Shock Resistance

21 *points*

## Alloy Composition

Among alloy steels, the composition of SAE-AISI 9255 steel is notable for containing a comparatively high amount of silicon (Si). Silicon content is typically governed by metallurgical processing concerns, and not its effects on final material properties. However, it does have a modest strengthening effect.

Fe | 96.2 to 97 | |

Si | 1.8 to 2.2 | |

Mn | 0.7 to 1.0 | |

C | 0.51 to 0.59 | |

S | 0 to 0.040 | |

P | 0 to 0.035 |

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

## Followup Questions

## Similar Alloys

## Further Reading

ASTM A752: Standard Specification for General Requirements for Wire Rods and Coarse Round Wire, Alloy Steel

ASM Specialty Handbook: Carbon and Alloy Steels, J. R. Davis (editor), 1996

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

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