M35 | 1.3243 | SKH-55
M35 (1.3243 / HS6-5-2-5) is a cobalt-alloyed high-speed steel offering excellent red hardness, wear resistance, and tempering resistance. It maintains cutting performance at elevated temperatures, making it suitable for demanding drilling, milling, tapping, and precision cutting applications.
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 |
| 1.3243 | HS6-5-2-5 | M35 | SKH-55 |
Chemical Composition(wt%)
| C | Si | Mn | Cr | Mo | W | V |
| 0.80~0.85 | 0.20~0.40 | 0.20~0.40 | 3.90~4.40 | 4.75~5.25 | 6.15~6.65 | 1.75~2.15 |
Physical Properties
Density：8.10 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) | 9.7 | 10.5 | 11 | 11.4 |
Heat Treatment Process
Hardening: Pre-heat the steel, then heat to 1220~1245°C until the whole section reaches temperature. Quench in oil, air, or warm bath to cool.
Annealing: Heat the steel to 870~900°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: 540~600°C, HRC: 65~60 (Perform 2~3 times).
Application Fields
High-stress drills, milling cutters, profile cutting tools, thread cutting drills and cold forming tools.
Disclaimer: the information and data presented herein are typical values for reference and are not intended as warranties to readers.
