Sep 18 2012
Topics Covered
IntroductionChemical
CompositionPhysical PropertiesMechanical PropertiesOther DesignationsFabrication and Heat treatment Welding Forging Hot
Working Cold
WorkingApplications
Introduction
Copper beryllium alloys have good thermal and electrical properties and high
tensile strength. High conductivity alloys and high strength alloys are the two
main categories of copper beryllium alloys. The high conductivity alloys have
0.2-0.7% of beryllium and high cobalt and nickel contents. The wrought high
strength alloys contain 1.6 to 2.0% of beryllium and nearly 0.3% of cobalt and
the cast high-strength alloys have beryllium up to 2.7%. The cast alloys are
designated as C82000 to C82800, and the wrought alloys are named as C17200 to
C17400.
The tensile strength of the copper beryllium alloys can be improved by age
hardening or precipitation hardening. The cast alloys contain alpha copper
dendritic structure and beryllide phases. The wrought alloys are provided with a
microstructure that has twinned grains of alpha copper and cobalt, nickel or
cobalt and nickel beryllide particles dispersed in the structure.
The following section will discuss in detail about UNS C17500 beryllium
copper alloys, which have ductility and heat treatable and mill hardening
properties. These alloys are used in applications, which require good
conductivity, high strength and stiffness.
Chemical Composition
The following table shows the chemical composition of UNS C17500 copper
alloys.
| Element |
Content
(%) |
| Cu |
96.9 |
| Be |
2.5 |
| Co |
0.6 |
Physical Properties
The physical properties of UNS C17500 copper alloys are given in the
following table.
| Properties |
Metric |
Imperial |
| Density |
8.60 g/cm3 |
0.311 lb/in3 |
| Melting point |
1029°C |
1885°F |
Mechanical Properties
The mechanical properties of UNS C17500 copper alloys are tabulated
below.
| Properties |
Conditions |
| T
(°C) |
Treatment |
| Poisson's ratio |
0.34 |
25 |
- |
| Elastic modulus |
117 GPa |
25 |
- |
| Tensile strength |
310-793 MPa |
- |
- |
| Yield strength |
172-758 MPa |
25 |
(flat products, rod) |
| Elongation |
28% |
- |
- |
Other Designations
Other designations that are equivalent to UNS C17500 copper alloys
include:
- UNS C17500
- ASTM B441
- ASTM B534
- MIL C-81021
- SAE J461
- SAE J463
Fabrication and Heat Treatment
Welding
Welding methods such as soldering, brazing, gas shielded arc welding, coated
metal arc welding, spot welding, seam welding and butt welding are recommended
for C17500 copper alloys. Oxyacetylene welding is generally not preferred for
this type of alloys.
Forging
C17500 copper alloys are forged at temperature ranging from 649 to 885°C
(1200 to 1625°F).
Hot Working
C17500 copper alloys have good hot working property.
Cold Working
C17500 copper alloys have excellent cold working property.
Applications
The following are the major applications of UNS C17500 copper alloys:
| Bearings |
Precision screw machined parts |
| Plastic molds |
Electrical/electronic connectors |
| Welding electrodes |
Corrosion resistant components |
| Current-carrying springs |
Housings for magnetic sensing devices |