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Hardened M7 Tool Steel

Hardened SAE-AISI M7 is SAE-AISI M7 steel in the hardened (H) condition. The graph bars on the material properties cards below compare hardened SAE-AISI M7 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

200 GPa 29 x 106 psi

Poisson's Ratio

0.29

Rockwell C Hardness

68

Shear Modulus

77 GPa 11 x 106 psi

Tensile Strength: Ultimate (UTS)

2210 MPa 320 x 103 psi

Thermal Properties

Latent Heat of Fusion

270 J/g

Melting Completion (Liquidus)

1560 °C 2830 °F

Melting Onset (Solidus)

1510 °C 2750 °F

Specific Heat Capacity

450 J/kg-K 0.11 BTU/lb-°F

Thermal Conductivity

28 W/m-K 16 BTU/h-ft-°F

Thermal Expansion

12 µm/m-K

Otherwise Unclassified Properties

Base Metal Price

18 % relative

Density

8.1 g/cm3 500 lb/ft3

Embodied Carbon

8.9 kg CO2/kg material

Embodied Energy

130 MJ/kg 56 x 103 BTU/lb

Embodied Water

100 L/kg 12 gal/lb

Common Calculations

PREN (Pitting Resistance)

35

Stiffness to Weight: Axial

14 points

Stiffness to Weight: Bending

24 points

Strength to Weight: Axial

76 points

Strength to Weight: Bending

47 points

Thermal Diffusivity

7.8 mm2/s

Thermal Shock Resistance

69 points

Alloy Composition

Iron (Fe)Fe 79.8 to 83.8
Molybdenum (Mo)Mo 8.2 to 9.2
Chromium (Cr)Cr 3.5 to 4.0
Vanadium (V)V 1.8 to 2.3
Tungsten (W)W 1.4 to 2.1
Carbon (C)C 1.0 to 1.1
Silicon (Si)Si 0.2 to 0.55
Manganese (Mn)Mn 0.15 to 0.4
Nickel (Ni)Ni 0 to 0.3
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 A600: Standard Specification for Tool Steel High Speed

Tool Steels, 5th ed., George Roberts et al., 1998

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

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