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SAE-AISI M48 (T11348) Cobalt High-Speed Steel

SAE-AISI M48 steel is a tool steel. M48 is the designation in both the SAE and AISI systems for this material. T11348 is the UNS number.

The properties of SAE-AISI M48 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 M48 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

78 GPa 11 x 106 psi

Tensile Strength: Ultimate (UTS)

890 to 2390 MPa 130 to 350 x 103 psi

Thermal Properties

Latent Heat of Fusion

260 J/g

Melting Completion (Liquidus)

1670 °C 3040 °F

Melting Onset (Solidus)

1620 °C 2950 °F

Specific Heat Capacity

420 J/kg-K 0.1 BTU/lb-°F

Thermal Expansion

12 µm/m-K

Otherwise Unclassified Properties

Base Metal Price

48 % relative


8.7 g/cm3 550 lb/ft3

Embodied Carbon

13 kg CO2/kg material

Embodied Energy

190 MJ/kg 83 x 103 BTU/lb

Embodied Water

160 L/kg 19 gal/lb

Common Calculations

PREN (Pitting Resistance)


Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

22 points

Strength to Weight: Axial

28 to 76 points

Strength to Weight: Bending

23 to 45 points

Thermal Shock Resistance

26 to 71 points

Alloy Composition

Iron (Fe)Fe 63.8 to 69.8
Tungsten (W)W 9.5 to 10.5
Cobalt (Co)Co 8.0 to 10
Molybdenum (Mo)Mo 4.8 to 5.5
Chromium (Cr)Cr 3.5 to 4.0
Vanadium (V)V 2.8 to 3.3
Carbon (C)C 1.4 to 1.5
Manganese (Mn)Mn 0.15 to 0.4
Silicon (Si)Si 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

Similar Alloys

Further Reading

ASTM A600: Standard Specification for Tool Steel High Speed

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

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

CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015