M42 | 1.3247 | SKH-59
M42 (1.3247 / HS2-9-1-8) is a cobalt-alloyed high-speed steel offering excellent red hardness, wear resistance, and cutting performance. Its superior hot hardness makes it ideal for high-speed machining and cutting difficult-to-machine materials, including titanium and nickel-based alloys.
Available Form
Round Bar
Custom Diameter & Length
Flat Bar
Custom Thickness, Width & Length
Square Bar
Custom Width & Length
Steel Plate
Custom Thickness, Width & Length
Steel Grade Comparison
| W-Nr | EN | AISI | JIS |
| 1.3247 | HS2-9-1-8 | M42 | SKH-59 |
Chemical Composition(wt%)
| C | Si | Mn | Cr | Mo | W | V | Co |
| 1.05~1.15 | 0.15~0.65 | 0.15~0.40 | 3.50~4.25 | 9.00~10.0 | 1.15~1.85 | 0.95~1.35 | 7.75~8.75 |
Physical Properties
Density: 8.01 g/cm³
Modulus of Elasticity: 217 GPa
Thermal Conductivity: 19.0 W/(m.K)
| Temperature | 20-100°C | 2-200°C | 2-300°C | 2-400°C |
| Coefficient of Thermal Expansion (×10-6 /K) | 9.8 | 10.8 | 11.1 | 11.6 |
Heat Treatment Process
Hardening: Pre-heat the steel, then heat to 1170~1210°C until the whole section reaches temperature. Quench in oil, air, or warm bath to cool.
Annealing: Heat the steel to 770~820°C, hold it well at temperature, and then let it cool slowly inside the furnace.
Tempering: Heat the steel uniformly, hold it at the selected tempering temperature, and then allow it to cool in still air. Tempering temperature: 530~550°C, HRC: 66~69 (Perform 3 times).
Application Fields
For drills, hobs, taps, end mills, milling cutters, form tools, gear cutting tools, broaches and slotting machines, etc.
Disclaimer: the information and data presented herein are typical values for reference and are not intended as warranties to readers.
