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.
| 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