CU · copper alloy
Free-Cutting Brass C36000
The reference point for the whole scale: free-cutting brass is 100% machinability in every published table and a 10 here. It breaks a chip, takes a mirror finish and turns faster than anything else we cut.
Quoting this material
- Typical lead time
- 7–12 working days
- Condition
- Cold drawn (higher strength) or annealed
- Achievable finish
- Ra 0.8 µm 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.
The reference point for the whole scale: free-cutting brass is 100% machinability in every published table and a 10 here. It breaks a chip, takes a mirror finish and turns faster than anything else we cut.
Properties as supplied
| Parameter | Value | Unit |
|---|---|---|
| Tensile strength | 400 | MPa |
| Yield strength (0.2%) | 310 | MPa |
| Elongation | 15 | % |
| Hardness | 130 | HB |
| Thermal conductivity | 115 | W/m·K |
| Modulus of elasticity | 97 | 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
Cold drawn (higher strength) or annealed
Heat treatment
Not hardenable by heat treatment; strength comes from cold work. Stress relief at 260–300 °C is used when a machined part would otherwise stress-crack in service.
Achievable surface finish
Ra 0.8 µm
Ra 0.2 µm
Produces the brightest as-machined finish of any metal here, which is why visible brass fittings are usually left unfinished.
Tooling and cutting parameters
Cutting speed
- 200–400 m/min (carbide)
Feed
- 0.10–0.40 mm/rev turning · 0.08–0.25 mm/tooth milling
Tooling
- Uncoated carbide, high positive rake; a dedicated brass geometry if the volume justifies it
Coolant
- Often run dry for brass; mist for tapping and deep holes
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
- Plumbing and pneumatic fittings
- Electrical connectors and terminals
- Valve bodies and stems
- Instrument and gauge hardware
- Decorative machined hardware
DFM notes for this grade
- Not recommended for anything that will be soldered or brazed after machining - the lead content is there for machinability and it embrittles the joint
- Dezincification risk in aggressive or high-chloride water: a brass fitting in a salt-water line will lose zinc and go porous
- Lead content makes it unsuitable where a potable-water or RoHS-restricted specification applies - that is a real limit on plumbing work in some markets
Questions buyers ask
- Why is free-cutting brass so easy to machine?
- Lead is dispersed through the brass as tiny separate particles that act as built-in chip breakers and lubricant at the cutting edge. That is why the chip comes off in small segments and the tool lasts, and it is exactly the same mechanism as in leaded steel - with the same consequence, that the material cannot be welded.
- Is brass a problem for potable water in Europe?
- It can be. The lead in free-cutting brass is a regulated concern for drinking-water fittings, which is why dezincification-resistant and lead-free brasses exist for that market. Confirm the specification before quoting a potable-water part in C360.
Grades we would quote instead
C26000 Cartridge Brass
8/10The 70/30 brass: excellent cold-forming and good machining, though without the lead it does not break a chip as cleanly as C360.
C65500 Silicon Bronze
6/10A tough, corrosion-resistant bronze that machines reasonably in the annealed condition and work-hardens quickly.
C93200 Bearing Bronze
6/10The standard bearing bronze: it machines well, it is soft enough to embed grit, and it runs against a steel shaft without galling.