TS · tool steel
Tool Steel M2 (high speed steel)
High speed steel: hard (60–65 HRC), abrasion resistant and unpleasant to machine in any state. It is bought for tools that cut hot, and it is almost always supplied as finished tooling rather than stock.
Quoting this material
- Typical lead time
- 15–25 working days
- Condition
- Annealed for machining, or supplied as finished cutters
- Achievable finish
- Ra 0.4 µm after grinding typical · Ra 0.2 µm best
Machined in-house to your drawing: see the precision CNC machining service and the machine and inspection capability it runs on.
Machinability
Our own 1–10 shop ranking, not a published index: 10 is free-cutting brass C360, 1 is Inconel 718. It ranks how a material behaves on the floor - cycle time, chip control and tool life together. Where a published index exists it is quoted in the note.
High speed steel: hard (60–65 HRC), abrasion resistant and unpleasant to machine in any state. It is bought for tools that cut hot, and it is almost always supplied as finished tooling rather than stock.
Properties as supplied
| Parameter | Value | Unit |
|---|---|---|
| Hardness (working) | 60–65 | HRC |
| Hot hardness | Retained to 500 °C+ | - |
| Wear resistance | Very high | - |
| Toughness | Moderate | - |
| Thermal conductivity | 24 | W/m·K |
| Modulus of elasticity | 217 | GPa |
Hardness, tensile and thermal figures are typical published values for the condition stated. Actual mill certificates govern; send the specification with the drawing and we confirm against the certificate before the material is cut.
Condition
Annealed for machining, or supplied as finished cutters
Heat treatment
Austenitise around 1,200–1,225 °C (which is why it is done in a vacuum or salt bath), quench, then temper two or three times at 540–560 °C. The triple temper is what develops the secondary hardness that lets it cut at 500 °C.
Achievable surface finish
Ra 0.4 µm after grinding
Ra 0.2 µm
Ground cutting geometry; a tool edge is a ground edge, not a polished one.
Tooling and cutting parameters
Cutting speed
- 60–120 m/min annealed (carbide) · 20–40 m/min at 64 HRC (CBN)
Feed
- 0.06–0.18 mm/rev turning · 0.04–0.10 mm/tooth milling
Tooling
- Coated carbide annealed; CBN or ceramic for hardened; EDM for form detail
Coolant
- Flood, and expect heavy tool consumption
Starting points for carbide on a rigid setup, not a guarantee. The right numbers depend on the machine, the toolholder and the fixturing - ask and we will say what we would actually run.
Typical applications
- Drills, reamers and taps (as tooling)
- Milling cutters and form tools
- Punches for high-volume work
- Broaches and gear-cutting tools
- Wear parts in hot service
DFM notes for this grade
- Machining M2 to a finished tool is specialist work: the grinding and the heat treatment dominate the cost, not the turning
- Hot hardness is the property being bought - do not judge it against cold wear resistance, where D2 is competitive and far easier to handle
- It is almost never the right answer for a fixture or a die; it is an edge material
Questions buyers ask
- Why would a shop machine M2 rather than buy a finished cutter?
- For form tools, special broaches and stepped cutters that are not catalogue items. The economics are poor for anything standard - a bought drill or endmill in M2 or a modern powder-metal equivalent costs less than the stock plus the grinding time.
- What makes high speed steel different from other tool steels?
- Tungsten and molybdenum carbides that stay hard when the tool gets hot. A D2 die loses its hardness in service above about 200 °C; M2 holds 60 HRC at 500 °C, which is what makes a cutting edge survive in a cut where ordinary tool steel would soften and fail.