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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 106 psi

Elongation at Break

21 %

Fatigue Strength

270 MPa 39 x 103 psi

Poisson's Ratio

0.29

Shear Modulus

72 GPa 10 x 106 psi

Shear Strength

430 MPa 62 x 103 psi

Tensile Strength: Ultimate (UTS)

680 MPa 98 x 103 psi

Tensile Strength: Yield (Proof)

390 MPa 56 x 103 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/cm3 480 lb/ft3

Embodied Carbon

1.5 kg CO2/kg material

Embodied Energy

20 MJ/kg 8.4 x 103 BTU/lb

Embodied Water

46 L/kg 5.4 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

120 MJ/m3

Resilience: Unit (Modulus of Resilience)

400 kJ/m3

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 mm2/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.

Iron (Fe)Fe 96.2 to 97
Silicon (Si)Si 1.8 to 2.2
Manganese (Mn)Mn 0.7 to 1.0
Carbon (C)C 0.51 to 0.59
Sulfur (S)S 0 to 0.040
Phosphorus (P)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