High-Speed Steel (HSS)
High-speed steel (HSS) is a tool steel alloyed with tungsten, molybdenum, vanadium and often cobalt that keeps its hardness (around 62–67 HRC) at the high temperatures generated in cutting. It is used for drills, taps, reamers, broaches, form tools and punches.
What it is
Grades such as M2 (general purpose), M35/M42 (cobalt for hot hardness) and T1 resist softening up to around 550–600 °C, so tools stay sharp at higher cutting speeds than carbon tool steels.
HSS is tougher than carbide, making it better for interrupted cuts, form tools and applications where edge chipping is a risk.
Typical applications
- Drills, taps and reamers
- Broaches and form tools
- Milling cutters and saws
- Punches for tough materials
- Special cutting tools
Materials & grades
- M2
- M35 (5% cobalt)
- M42 (8% cobalt)
- T1 / T42
- Powder-metallurgy HSS
Points to consider
- Cobalt grades suit harder and stainless materials.
- Carbide cuts faster but HSS is tougher and cheaper for special tools.
- Coatings (TiN, TiAlN) extend HSS tool life.
- Tools can be reground several times.
Frequently asked questions
HSS or carbide tools?
Carbide cuts faster and lasts longer in stable conditions; HSS is tougher, cheaper and better for interrupted cuts and special form tools.
What is M42 HSS?
A cobalt high-speed steel with about 8% cobalt, offering higher hot hardness for tough and stainless materials.
Can HSS tools be resharpened?
Yes, they can be reground many times, which keeps tooling costs low.