Background Bronzes are copper-based alloys. Major alloying elements are often, but not always, zinc and tin. They offer a combination of properties such as high strength, hardness, corrosion resistance and wear resistance.
Aluminium BronzesCopper-Aluminium alloys are commonly known as Aluminium Bronzes. These alloys cover 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% Aluminium.
· Two-phase or duplex alloys containing 8 to 11% Aluminium. These alloys also frequently have additions of Iron and Nickel to increase strength. This group contains casting alloys AB1 and AB2, the wrought alloys CA105, CA104 and Naval Engineering Standard (NES) alloys (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 NES833Alloy NES833 is an Aluminium Bronze with good ductility and impact strength. It also has superior corrosion resistance. Chemical Composition Table 1. Typical chemical composition for bronze alloy NES833
% NES833 Cu 82 Pb - Sn - Fe 4.2 Al 9.3 Mn 0.3 Zn - Si - Ni 4.2
Properties Mechanical PropertiesTable 2. Typical mechanical properties for bronze alloy NES833
Grade NES833 Tensile Strength (MPa) 635 Proof Stress 0.2% (MPa) 295 Elongation A5 (%) 17 Hardness HB 150
Physical PropertiesTable 3. Typical physical properties for bronze alloy NES833
Property Value Density 7.5 g/cm3 Electrical Resistivity 0.172x10-6 Ω.m Thermal Conductivity 42 W/m.K at 20°C
Alloy DesignationsBronze alloy NES833 corresponds to the following designations:
European British Proprietary CW307G DGS1043 Hidurax
Corrosion ResistanceNES833 has high corrosion resistance, particularly in marine environments. Alloy NES833 is immune to chloride stress corrosion cracking.
This alloy also has excellent resistance to cavitation erosion.
Temperature ResistanceBronze alloy NES833 largely retains its strength and hardness up to 400°C.
It is also resistant to high temperature scaling at up to 1000°C.
FabricationWelding and JoiningBronze alloy NES833 is fully weldable by common welding methods.
MachinabilityNES833 has good machinability.
ApplicationsAluminium bronze NES833 is typically used in:
· Marine Valves
· Pumps
· Weapons handling systems
· Couplings
· Fasteners
· Gears
· Marine propeller shafts
Supplied FormNES833 is typically supplied by Aalco in the following form:
· Hexagon Bar
· Round Rod