1. High-speed steels Service conditions: High contact stresses
Bending and twisting loads
Heating of cutting edges
Surface abrasion with chips
Vibrations

2. Requirements for material:
High-speed steels
Requirements for material:
High hardness (HRC 62-68)
High wear resistance
Sufficient strength
Sufficient toughness
Heat resistance (red-hardness) is
an ability to keep cutting properties upon long heating

3. Composition of high-speed steels
Grade (Russian system)
Alloying elements, % С Cr W Mo V Co
Р18 -
Р6М5
Р6М5К5

4. High-speed steels :
secondary hardness arises in the process of tempering, in the issue of partial martensite decomposition and precipitation of dispersed carbides (carbide fines)

5. High-speed steels :
Heat treatment includes quenching from high temperature and triple tempering
Stage Cooling Triple tempering
heating in hot medium

6. High-speed Steel Structure (grade Р6М5, Russian classification system)
Annealed steel
Quenched steel
Tempered steel
carbides
martensite
primary carbides
tempered martensite
secondary carbides