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Copper
Material Type
Metal
Process Compatibility
Metal Stamping, CNC Machining
Physical Properties
Property |
Value/Description |
|---|---|
| Atomic Number | 29 |
| Density | 8.96 g/cm³ (Heavier than steel but lighter than tungsten) |
| Melting Point | 1083°C (Suitable for high-temperature applications) |
| Boiling Point | 2567°C |
| Thermal Conductivity | 401 W/(m·K) (Highest among industrial metals, excellent for heat dissipation) |
| Electrical Conductivity | 100% IACS (International Annealed Copper Standard, benchmark for conductivity) |
| Thermal Expansion Coefficient | 17 ×10⁻⁶/°C (Similar to stainless steel, good thermal stability) |
| Color | Reddish-brown (Turns green when oxidized) |
Mechanical Properties
Property |
Value/Description |
|---|---|
| Tensile Strength | Pure Copper: 200-250 MPa; Beryllium Copper (C17200): ≥1200 MPa (Heat-treatable) |
| Yield Strength | Pure Copper: 33 MPa; Beryllium Copper (Aged): ≥1000 MPa |
| Elastic Modulus | 110-128 GPa (Higher than aluminum but lower than steel) |
| Hardness | Pure Copper: 35-45 HB; Beryllium Copper (C17200): ≥350 HB |
| Ductility | Elongation: ≥50% for pure copper (Excellent cold-working properties) |
| Fatigue Strength | Beryllium Copper: ≈300 MPa (Surface treatment required for high-cycle applications) |
Chemical Properties
Property |
Description |
|---|---|
| Corrosion Resistance | Resistant to atmospheric and water corrosion, but vulnerable to sulfides/ammonia (Requires plating) |
| Oxidation | Slowly oxidizes at room temperature (Forms Cu₂O/CuO); develops patina (basic copper carbonate) in humid environments |
| Common Alloying Elements | Be, Zn, Sn, Ni (e.g., Beryllium Copper, Brass, Bronze) |
Machinability (Key for Mold Making)
Property |
Description |
|---|---|
| Machinability | Pure copper tends to stick to tools (Requires sharp tools + high cutting speed); Beryllium copper machines well |
| Castability | Excellent fluidity (~1.5% shrinkage, ideal for precision casting) |
| Weldability | Easy to weld (but heat-affected zone may soften) |
| Polishing | Capable of mirror finish (Common for EDM electrodes) |
| Heat Treatment | Beryllium copper can be age-hardened (315°C × 2h, increases hardness 2-3x) |
Mold Industry Applications
Advantages:
- Top-tier thermal/electrical conductivity (Increases injection mold cooling speed by 30%+)
- Better wear resistance than aluminum (Ideal for sliders and inserts)
- Non-magnetic (Critical for precision electronic molds)
Limitations:
- High cost (Pure copper prices fluctuate significantly)
- Limited high-temperature strength (Max continuous service temperature ≤250°C)
Recommended Copper Alloys
Grade |
Characteristics |
Mold Applications |
|---|---|---|
| C11000 | Pure copper (99.9%), high thermal/electrical conductivity | Cooling inserts, EDM electrodes |
| C17200 | Beryllium copper (1.9% Be), ultra-high strength | Injection mold sliders, high-wear inserts |
| C36000 | Leaded brass, excellent machinability | Rapid prototyping molds, low-load parts |
| C95400 | Aluminum bronze, corrosion/wear resistant | Die-casting sprue bushes, corrosive environments |
Other Metal Material Selection
Stainless Steel
Aluminum Materials
Carbon Steel
Special Alloy
FAQ Of Copper Materials
Visit our FAQ center for more questions.
Why does Copper have excellent electrical/thermal conductivity?
Copper’s conductivity (58.5×10⁶ S/m) and thermal conductivity (401 W/(m·K)) are second only to silver, due to:
- High free electron density (8.5×10²⁸/m³)
- FCC crystal structure
- Low impurity (99.9% purity gives 1.68μΩ·cm resistivity)
How to select Copper Alloys? What do colors indicate?
Key copper alloys:
-
Brass (Cu-Zn): Golden, excellent machinability
-
Bronze (Cu-Sn): Grayish, wear-resistant
-
Cupronickel (Cu-Ni): Silver-white, seawater-resistant
-
Beryllium copper: High strength (1200MPa) + conductivity
Why does Copper turn green? How to prevent?
Patina (basic copper carbonate) forms when:
Humidity >60% + CO₂/O₂ + 2+ years
Protection methods:
- Chemical passivation (BTA treatment)
- Ni/Cr electroplating (5-10μm)
- Regular polishing