Introdução
Cast copper alloys are widely used in various industries due to their excellent properties, including corrosion resistance, thermal conductivity, and ease of casting. These alloys are produced by melting and pouring copper and other elements into molds to create complex shapes. This article explores the common types of cast copper alloys, their properties, and applications.
Copper-Tin Alloys (Bronze)
Bronze alloys are among the most common cast copper alloys. They typically contain copper and tin as the primary elements.
| Tipo de liga | Propriedades principais | Aplicações Comuns | Resistência à tração (MPa) | Dureza (HB) |
|---|---|---|---|---|
| High-Tin Bronze | High strength, good corrosion resistance | Bearings, bushings, gears | 310-380 | 80-100 |
| Medium-Tin Bronze | Excellent wear resistance, low frictio | Valve seats, pump components | 240-310 | 60-85 |
| Bell Bronze | High hardness, good machinability | Bells, musical instruments | 200-240 | 90-110 |
Bronze alloys offer a good balance of strength, wear resistance, and corrosion resistance, making them suitable for various industrial applications.
Copper-Zinc Alloys (Brass)
Brass alloys are copper-zinc alloys that are widely used due to their excellent formability and machinability.
| Tipo de liga | Propriedades principais | Aplicações Comuns | Resistência à tração (MPa) | Alongamento (%) |
|---|---|---|---|---|
| Yellow Brass | Good strength, excellent machinability | Plumbing fixtures, decorative hardware | 230-350 | 20-35 |
| High-Strength Brass | High ductility, good corrosion resistance | Architectural components, marine hardware | 380-550 | 15-25 |
| Leaded Brass | Excellent machinability, low cost | Valves, fittings, ornamental castings | 220-310 | 20-30 |
Brass alloys are known for their golden color and are often used in decorative applications as well as functional components.
Copper-Aluminum Alloys (Aluminum Bronze)
Aluminum bronze alloys combine the properties of copper with the strength and lightness of aluminum.
| Tipo de liga | Propriedades principais | Aplicações Comuns | Resistência à tração (MPa) | Força de rendimento (MPa) |
|---|---|---|---|---|
| Single-Phase Al Bronze | High strength, excellent corrosion resistance | Marine propellers, pump impellers | 550-650 | 250-300 |
| Duplex Al Bronze | Good wear resistance, high strength | Bearings, gears, valve components | 600-750 | 280-350 |
| Nickel-Al Bronze | Excellent strength at high temperatures | Aircraft components, turbine blades | 650-800 | 300-400 |
Aluminum bronze alloys are particularly valued for their high strength and excellent corrosion resistance in marine environments.
Copper-Silicon Alloys (Silicon Bronze)
Silicon bronze alloys offer a combination of high strength and excellent corrosion resistance.
| Tipo de liga | Propriedades principais | Aplicações Comuns | Resistência à tração (MPa) | Condutividade elétrica (%IACS) |
|---|---|---|---|---|
| Low-Silicon Bronze | High strength, good ductility | Marine hardware, architectural fittings | 380-480 | 15-20 |
| Medium-Silicon Bronze | Excellent corrosion resistance, good weldability | Pump components, valve bodies | 410-520 | 7-10 |
| High-Silicon Bronze | High strength, good wear resistance | Bearings, bushings, gears | 450-550 | 5-8 |
Silicon bronze alloys are often used in applications requiring high strength and corrosion resistance, particularly in marine and architectural applications.
Copper-Nickel Alloys
Copper-nickel alloys, also known as cupronickel, offer excellent corrosion resistance, especially in seawater.
| Tipo de liga | Propriedades principais | Aplicações Comuns | Resistência à tração (MPa) | Condutividade Térmica (W/m·K) |
|---|---|---|---|---|
| 70-30 Cupronickel | Excelente resistência à corrosão da água do mar | Marine valves, pumps, heat exchangers | 330-380 | 29 |
| 90-10 Cupronickel | High strength, good erosion resistance | Propeller shafts, marine fittings | 280-330 | 50 |
| 55-45 Cupronickel | Superior corrosion resistance, high strength | Chemical processing equipment, desalination plants | 400-450 | 21 |
Copper-nickel alloys are extensively used in marine and chemical processing industries due to their exceptional corrosion resistance.
High-Strength Copper Alloys
These alloys are designed for applications requiring high strength and hardness.
| Tipo de liga | Propriedades principais | Aplicações Comuns | Resistência à tração (MPa) | Força de rendimento (MPa) |
|---|---|---|---|---|
| Manganese Bronze | Very high strength, good wear resistance | Heavy-duty bearings, worm gears | 650-750 | 320-380 |
| Nickel-Aluminum Bronze | High strength, good corrosion resistance | Marine propellers, pump impellers | 600-700 | 280-350 |
| Nickel-Silicon Bronze | Excellent strength, good corrosion resistance | Hydraulic valve bodies, submarine propellers | 700-800 | 350-400 |
These high-strength alloys are used in applications where standard bronze or brass alloys may not provide sufficient strength or wear resistance.
Conclusão
Cast copper alloys offer a wide range of properties suitable for diverse applications across many industries. From the high strength of aluminum bronzes to the excellent corrosion resistance of copper-nickel alloys, there is a cast copper alloy suitable for almost any engineering requirement. The choice of alloy depends on the specific application, considering factors such as strength, corrosion resistance, wear resistance, machinability, and cost.
As materials science continues to advance, new cast copper alloys are being developed to meet emerging technological needs and environmental regulations. The versatility and performance of cast copper alloys ensure their continued importance in modern engineering and manufacturing.