SAE-AISI M4 (T11304) Molybdenum High-Speed Steel

SAE-AISI M4 steel is a tool steel. M4 is the designation in both the SAE and AISI systems for this material. T11304 is the UNS number.

The properties of SAE-AISI M4 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 M4 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.

Annealed M4 Tool Steel Hardened M4 Tool Steel

Mechanical Properties

Elastic (Young's, Tensile) Modulus

200 GPa 28 x 10⁶ psi

Poisson's Ratio

0.29

Shear Modulus

76 GPa 11 x 10⁶ psi

Tensile Strength: Ultimate (UTS)

770 to 2150 MPa 110 to 310 x 10³ psi

Thermal Properties

Latent Heat of Fusion

260 J/g

Melting Completion (Liquidus)

1610 °C 2930 °F

Melting Onset (Solidus)

1560 °C 2840 °F

Specific Heat Capacity

440 J/kg-K 0.11 BTU/lb-°F

Thermal Conductivity

25 W/m-K 15 BTU/h-ft-°F

Thermal Expansion

12 µm/m-K

Otherwise Unclassified Properties

Base Metal Price

25 % relative

Density

8.3 g/cm³ 520 lb/ft³

Embodied Carbon

14 kg CO₂/kg material

Embodied Energy

210 MJ/kg 91 x 10³ BTU/lb

Embodied Water

110 L/kg 13 gal/lb

Common Calculations

PREN (Pitting Resistance)

Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

23 points

Strength to Weight: Axial

26 to 72 points

Strength to Weight: Bending

23 to 45 points

Thermal Diffusivity

6.9 mm²/s

Thermal Shock Resistance

24 to 68 points

Alloy Composition

Iron (Fe)Fe		75.9 to 81.4
Tungsten (W)W		5.3 to 6.5
Molybdenum (Mo)Mo		4.3 to 5.5
Chromium (Cr)Cr		3.8 to 4.8
Vanadium (V)V		3.8 to 4.5
Carbon (C)C		1.3 to 1.4
Silicon (Si)Si		0.2 to 0.45
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