C17300 Beryllium Copper Alloy (Free-Cutting Beryllium Copper)
1. Overview
C17300 is a free-machining beryllium copper alloy (CuBe2Pb) that contains a small amount of lead (Pb). It retains high strength, high hardness, and good electrical conductivity while significantly improving machinability. This precipitation-hardenable copper alloy offers excellent mechanical properties, corrosion resistance, and dimensional stability. It is widely used in industries requiring precision machining and high-strength conductive components, such as electrical contacts, switch blades, and automotive terminals.
2. Standards
UNS Number: C17300
ASTM Standards: ASTM B196, ASTM B197
RWMA Classification: Class 3 (Resistance welding electrode grade)
3. Chemical Composition (wt%)
Element | Content Range |
|---|---|
Copper (Cu) | Balance |
Beryllium (Be) | 1.8 – 2.0% |
Lead (Pb) | 0.2 – 0.6% |
Other Impurities | ≤ 0.5% |
4. Physical Properties
Property | Value Range |
|---|---|
Density | 8.25 g/cm³ |
Melting Point | 866 ~ 980 °C |
Electrical Conductivity | 15–28% IACS (depending on heat treatment) |
Thermal Conductivity | 105–130 W/m·K |
Specific Heat Capacity | 0.38 J/g·K |
Hardness (HV) | 250–380 (aged condition) |
5. Mechanical Properties (Typical Values)
Condition | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) |
|---|---|---|---|
Solution Annealed (A) | 400–540 | 200–250 | 30–45 |
Aged (HT) | 1000–1310 | 800–1100 | 5–10 |
Note: Actual properties may vary depending on size and processing method.
6. Processing and Heat Treatment
Heat Treatment:
After solution treatment, aging is performed at 290–370°C for 1–3 hours to achieve optimal mechanical properties.
Machinability:
The addition of lead improves chip breaking and tool life, making it suitable for automatic lathes and precision CNC machining.
Weldability:
Suitable for brazing and gas-shielded arc welding; not recommended for oxyacetylene welding.
7. Product Forms
Rods, plates, strips, wires, tubes, and custom-shaped components
Custom processing available for electrodes, springs, contact pins, connectors, etc., based on drawings
8. Application Fields
Electronics & Electrical: Relay springs, plug sockets, contact terminals, wear-resistant terminals
Automotive: ABS components, ignition contacts, terminal connectors
Aerospace: Circular connectors, contact pins, sensor brackets
Mold Making: Inserts for plastic molds, conductive components for hot runner systems
Resistance Welding Industry: Electrodes, clamps, locating pins
9. Comparison: C17200 vs. C17300
Feature | C17200 | C17300 |
|---|---|---|
Lead Content | None | Present (improves machinability) |
Machinability | Standard | Excellent |
Mechanical Strength | Higher | Slightly lower but easier to machine |
Preferred Use | General high-strength applications | Precision and automatic machining components |