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SAE-AISI M43 (T11343) Molybdenum High-Speed Steel

SAE-AISI M43 steel is a tool steel. M43 is the designation in both the SAE and AISI systems for this material. T11343 is the UNS number.

The properties of SAE-AISI M43 steel include two common variations. This page shows summary ranges across both of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare SAE-AISI M43 steel 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


Shear Modulus

77 GPa 11 x 106 psi

Tensile Strength: Ultimate (UTS)

810 to 2290 MPa 120 to 330 x 103 psi

Thermal Properties

Latent Heat of Fusion

270 J/g

Melting Completion (Liquidus)

1550 °C 2820 °F

Melting Onset (Solidus)

1500 °C 2730 °F

Specific Heat Capacity

450 J/kg-K 0.11 BTU/lb-°F

Thermal Conductivity

19 W/m-K 11 BTU/h-ft-°F

Thermal Expansion

12 µm/m-K

Otherwise Unclassified Properties

Base Metal Price

33 % relative


8.2 g/cm3 510 lb/ft3

Embodied Carbon

8.5 kg CO2/kg material

Embodied Energy

120 MJ/kg 53 x 103 BTU/lb

Embodied Water

140 L/kg 17 gal/lb

Common Calculations

PREN (Pitting Resistance)


Stiffness to Weight: Axial

14 points

Stiffness to Weight: Bending

24 points

Strength to Weight: Axial

27 to 77 points

Strength to Weight: Bending

24 to 47 points

Thermal Diffusivity

5.3 mm2/s

Thermal Shock Resistance

25 to 71 points

Alloy Composition

Iron (Fe)Fe 70.8 to 76
Cobalt (Co)Co 7.8 to 8.8
Molybdenum (Mo)Mo 7.5 to 8.5
Chromium (Cr)Cr 3.5 to 4.3
Tungsten (W)W 2.3 to 3.0
Vanadium (V)V 1.5 to 1.8
Carbon (C)C 1.2 to 1.3
Silicon (Si)Si 0.15 to 0.65
Manganese (Mn)Mn 0.2 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

Similar Alloys

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