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 Bronzes

Copper-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 NES833

Alloy 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 Properties

Table 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 Properties

Table 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 Designations

Bronze alloy NES833 corresponds to the following designations:

European


British


Proprietary

CW307G


DGS1043


Hidurax
Corrosion Resistance

NES833 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 Resistance

Bronze 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.
Fabrication
Welding and Joining

Bronze alloy NES833 is fully weldable by common welding methods.
Machinability

NES833 has good machinability.
Applications

Aluminium bronze NES833 is typically used in:

· Marine Valves

· Pumps

· Weapons handling systems

· Couplings

· Fasteners

· Gears

· Marine propeller shafts
Supplied Form

NES833 is typically supplied by Aalco in the following form:

· Hexagon Bar

· Round Rod