C18700 Free-Machining Copper (CuPb1P)

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MA18B is a free-machining high copper with machinability rating of 85, very high electrical conductivity, and good capacity for cold work. The alloy is used in applications where machined components from copper are required such as high current contacts, pins, and switch parts, as well as various hardware components with an expected electrical capacity.

Mechanical Properties

Round Rod

TEMPER NAME  TEMPER CODE  TENSILE STRENGTH YIELD STRENGTH ELONGATION MILL LIMITS 
min, ksi (MPa) min, ksi (MPa)
@ 0.5% EUL
min, %
half-hard H02 38 (260) 30 (205) 8 .0394 - .2500", incl.
(1 - 6.5mm, incl.)
38 (260) 30 (205) 12 over .2500 - .315000"
(over 6.5 - 8mm)
hard H04 48 (330) 40 (275) 4 .0394 - .2500", incl.
(1 - 6.5mm, incl.)
38 (260) 30 (205) 12 over .2500 - .315000"
(over 6.5 - 8mm)

Round Wire

TEMPER NAME  TEMPER CODE  TENSILE STRENGTH YIELD STRENGTH ELONGATION MILL LIMITS 
min, ksi (MPa) min, ksi (MPa)
@ 0.5% EUL
min, %
half-hard H02 38(260) - 6 0.0100 - 0.2362"
(0.25 - 6 mm)
hard H04 48 (330) - 4

Physical Properties

Melting Point (Liquidus) 1976°F 1080°C
Melting Point (Solidus) 1747°F 953°C
Annealing Range (min - max) 800 - 1200 °F 425 - 650 °C
Density 0.323 lb/cu in 8.94 gm/cu cm
Electrical Resistivity (Annealed) 10.8 Ω·cir-mil/ft @ 68 °F 1.79 µΩ·cm @ 20 °C
Electrical Conductivity (Annealed) 96% IACS @ 68°F 0.557 MS/cm @ 20°C
Thermal Conductivity 218 Btu/sq ft/ft·hr/°F @ 68 °F 377 W/m·K @ 20 °C
Coefficient of Thermal Expansion 0.0000098°F (68-572°F) 0.0000177°C (20-300°C)
Modulus of Elasticity (Tension) 17,000 ksi 117,000 MPa
Modulus of Rigidity 6,400 ksi 44,100 MPa