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CuZn36Pb3 (Standard Free-Cutting Brass)

CuZn36Pb3 -- 3% lead free-cutting brass, the classic "brass rod" material. Excellent machinability, good cold formability. For general turned brass components, valve stems, and hardware where CuZn39Pb3 free-machining performance is not fully required.

Copper Alloys Free-Machining Brass EN 12164CuZn36Pb3 / CW603N DIN W.NrCW603N UNSC34000 (nearest) ASTMB453 (nearest free-cutting brass rod) +3
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Description

CuZn36Pb3 (CW603N / C34000 nearest) per EN 12164. Pb (2.5-3.5%) in a lower-Zn (35-37%) alpha-beta brass base gives excellent machinability with somewhat better cold-forming behaviour than the higher-Pb, higher-Zn CuZn39Pb3. Standard general-purpose free-cutting brass for turned components, valve and tap hardware, and instrument parts where a balance of machinability and formability is needed.

Key Properties — Extruded/Drawn (H02)
Rm (Tensile Strength)
380 – 470
MPa
Re / Rp0.2 (Yield)
250
MPa
A₅ (Elongation)
≥ 15.0
%
Hardness
95 – 130
HB
E (Young's Modulus)
100
GPa
Density
8.47
g/cm³
Main Designations (7)
Standard BodyDesignationCountry / RegionNote
EN 12164 CuZn36Pb3 / CW603N EU
DIN W.Nr CW603N Germany
UNS C34000 (nearest) USA
ASTM B453 (nearest free-cutting brass rod) USA
BS EN CZ124 (nearest) / CW603N UK
JIS C3601 (nearest) Japan
JUS C.MZPb36 Yugoslavia/BiH Slobodnorezivi mesing CuZn36Pb3; JUS B.C5.520
Standards (7)
#Standard BodyDesignationCountry / RegionNote
1 EN 12164 CuZn36Pb3 / CW603N EU —
2 DIN W.Nr CW603N Germany —
3 UNS C34000 (nearest) USA —
4 ASTM B453 (nearest free-cutting brass rod) USA —
5 BS EN CZ124 (nearest) / CW603N UK —
6 JIS C3601 (nearest) Japan —
7 JUS C.MZPb36 Yugoslavia/BiH Slobodnorezivi mesing CuZn36Pb3; JUS B.C5.520
All values in wt.%
Cu
Copper
61.0000 – 63.0000
Zn
Zinc
34.0000 – 37.0000
Pb
Lead
2.5000 – 3.5000
ElementSymbolMin %Max %Typical %
Copper Cu 61.0000 63.0000 62.0000
Zinc Zn 34.0000 37.0000 35.5000
Lead Pb 2.5000 3.5000 3.0000
Mechanical Properties
ConditionCode Rm min
MPa		Rm max
MPa		 Re min
MPa		Re max
MPa		 A₅ min
%		 Z
%		 KV
J		 HB minHB max HRC minHRC max E
GPa
Extruded/Drawn (H02) H02 380 470 250 — 15.0 — — 95 130 — — 100.0
Annealed (O) +O 340 420 150 — 25.0 — — 75 105 — — 100.0
Physical Properties
Density
8.470
g/cm³
Melting Point
895–900
°C
Young's Modulus
100.0
GPa
Poisson's Ratio
0.350
—
Thermal Conductivity
120.0
W/m·K
Thermal Expansion
20.50
×10⁻⁶ /K
Specific Heat
377
J/kg·K
Electrical Resistivity
0.0640
µΩ·m
Magnetic
No
 
Heat Treatment
Annealing
Temperature:450°C – 600°C
Medium:Inert or reducing atmosphere
Duration:20-60 min
Cooling:Air or water cool
Hardness After:HB 75-105
Stress Relief
Temperature:150°C – 200°C
Medium:Air oven
Duration:1 h
Cooling:Air cool
Hardness After:Minimal
After machining or forming.
NOT hardenable
Medium:Duplex alpha-beta brass -- strength from composition and cold work only
Duration:N/A
Cooling:N/A
Hardness After:N/A
Extrusion (primary production route)
Temperature:650°C – 750°C
Medium:Hot extrusion press
Duration:N/A
Cooling:Air cool
Hardness After:Standard rod/bar stock
Rod and bar are hot extruded to size, then optionally cold drawn for H02 temper.
Machinability
Machinability Rating
relative to AISI B1112 = 100%
78.0%
Moderate
Turning Speed (HSS)
220
m/min
Turning Speed (Carbide)
975
m/min
Feed Rate (Turning)
0.410
mm/rev
Drilling Speed (HSS)
185
m/min
Milling Speed (Carbide)
985
m/min
CoolantLight oil mist or dry
Chip FormationShort chips due to Pb -- excellent chip control
Tool MaterialHSS M2; carbide K20; very high speeds achievable
Surface FinishRa 0.4-1.6 um
Excellent machinability -- classic free-cutting brass rod performance.
Applications
Turned Components
General-purpose turned brass components on automatic and CNC lathes.
Valve Hardware
Valve stems, spindles and small valve body components.
Instrument Parts
Precision instrument fittings and small mechanical components.
Hardware
General brass hardware requiring good machinability and moderate formability.
Technical Notes
✅
CuZn36Pb3 vs CuZn39Pb3 vs CuZn40Pb2
CuZn39Pb3: highest Pb+Zn, maximum machinability, standard for the highest-volume simplest turned parts. CuZn36Pb3: slightly lower Zn, marginally better cold formability while retaining excellent machining. CuZn40Pb2: optimised for hot stamping/forging rather than machining. Choose CuZn36Pb3 when a turned part also requires some post-machining cold forming (e.g. crimping or light bending).