Bronze Castings

Copper is alloyed with other elements because pure copper is extremely difficult to cast also as being prone to surface cracking, porosity problems, and to the formation of internal cavities.

The casting characteristics of copper are often improved by the addition of small amounts of elements including beryllium, silicon, nickel, tin, zinc, chromium, and silver. Alloy coppers, for instance, constituted to possess improved strength properties over those of high-purity copper, while maintaining a minimum of 85% conductivity, are widely used for cast electrical conducting members.

Copper alloys in cast form designated in UNS numbering system as C80000 - C99999.

Types of Copper Alloys:
Copper alloys are poured into many sorts of castings such as sand, shell, investment, permanent mold, chemical sand, centrifugal, and die. The copper-base casting alloy family are often subdivided into three groups according to solidification (freezing range).

The three groups are as follows:
Group I: Copper alloys that have a narrow freezing range, that is, a freezing range of of 50°C (90°F) between the liquidus and solidus.

Group II: Copper alloys that have an intermediate freezing range, that is, a freezing range of 50 to 110°C (90 to 200°F) between the liquidus and the solidus.

Group III: Copper alloys that have a good freezing range. These alloys have a freezing range of overflow 110°C (200°F), even up to 170°C (300°F).

Specific Applications:
Copper alloy castings are used in applications that require superior corrosion resistance, high thermal or electrical conductivity, and other special properties.

Copper Alloys can be divided into six basic groups:
• Plumbing hardware, pump parts, valves and fittings
• Bearings and bushings
• Gears
• Marine castings
• Electrical components
• Architectural and ornamental parts.