Bronzes are Copper-based alloys with the major alloying element being Tin. They offer a combination of properties such as high strength, hardness, corrosion resistance and wear resistance.
Copper-Aluminium alloys are commonly known as Aluminium Bronzes. These alloys are a range of Copper-based alloys in which the primary alloying element is up to 14% Aluminium. The four major groups of Aluminium Bronze are:
~ Single phase alloys containing less than 8% of Aluminium.
~ Two-phase (duplex) alloys containing 8 to 11% Aluminium. These alloys also frequently have additions of Iron and Nickel to increase strength. This group’s contains casting alloys AB1 and AB2, the wrought alloys CA105, CA104 and Defence Standard alloys (formerly Naval Engineering Standard, NES - NES 747 when cast and the wrought form NES 833).
~ The low magnetic permeability Aluminium-Silicon alloys.
~ The Copper-Manganese-Aluminium alloys with good castability.
Alloy Defence Standard (NES) 833 is an Aluminium Bronze with good ductility and impact strength. It also has superior corrosion resistance.
Applications
Aluminium Bronze to Defence Standard (NES) 833 is typically used in:
~ Marine Valves
~ Pumps
~ Weapons handling systems
~Couplings
~ Fasteners
~ Gears
~ Marine propeller shafts
Alloy Designations
Def-Stan (NES) 833 corresponds to the following designations:
DEF STAND 833
NES 833
DGS 1043
CW307G (not an exact equivalent)
Corrosion Resistance
Defence Standard (NES) 833 has high corrosion resistance, particularly in marine environments.
It is immune to chloride stress corrosion cracking.
This alloy also has excellent resistance to cavitation erosion.
Temperature Resistance
Defence Standard (NES) 833 largely retains its strength and hardness up to 400°C.
It is also resistant to high temperature scaling at up to 1000°C
Weldability
Defence Standard (NES) 833 is fully weldable by common welding methods.
Machinability
Machinability is poor rated at 30 compared to Brass CZ121 / CW614N which is rated as 100.