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Hardened A9 Tool Steel

Hardened SAE-AISI A9 is SAE-AISI A9 steel in the hardened (H) condition. The graph bars on the material properties cards below compare hardened SAE-AISI A9 to: tool 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

Elastic (Young's, Tensile) Modulus

190 GPa 28 x 106 psi

Poisson's Ratio

0.29

Rockwell C Hardness

63

Shear Modulus

74 GPa 11 x 106 psi

Tensile Strength: Ultimate (UTS)

2030 MPa 290 x 103 psi

Thermal Properties

Latent Heat of Fusion

280 J/g

Melting Completion (Liquidus)

1460 °C 2650 °F

Melting Onset (Solidus)

1410 °C 2580 °F

Specific Heat Capacity

470 J/kg-K 0.11 BTU/lb-°F

Thermal Conductivity

35 W/m-K 20 BTU/h-ft-°F

Thermal Expansion

12 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

7.9 % IACS

Electrical Conductivity: Equal Weight (Specific)

9.2 % IACS

Otherwise Unclassified Properties

Base Metal Price

7.0 % relative

Density

7.8 g/cm3 480 lb/ft3

Embodied Carbon

4.7 kg CO2/kg material

Embodied Energy

70 MJ/kg 30 x 103 BTU/lb

Embodied Water

82 L/kg 9.7 gal/lb

Common Calculations

PREN (Pitting Resistance)

10

Stiffness to Weight: Axial

14 points

Stiffness to Weight: Bending

25 points

Strength to Weight: Axial

73 points

Strength to Weight: Bending

46 points

Thermal Diffusivity

9.6 mm2/s

Thermal Shock Resistance

66 points

Alloy Composition

Iron (Fe)Fe 87 to 90.5
Chromium (Cr)Cr 4.8 to 5.5
Molybdenum (Mo)Mo 1.3 to 1.8
Nickel (Ni)Ni 1.3 to 1.8
Vanadium (V)V 0.8 to 1.4
Silicon (Si)Si 1.0 to 1.2
Carbon (C)C 0.45 to 0.55
Manganese (Mn)Mn 0 to 0.5
Copper (Cu)Cu 0 to 0.25
Phosphorus (P)P 0 to 0.030
Sulfur (S)S 0 to 0.030

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

Followup Questions

Further Reading

ASTM A681: Standard Specification for Tool Steels Alloy

Tool Steels: Properties and Performance, Rafael A. Mesquita (editor), 2016

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