Bronze

Tin Bronze and Phosphor Bronze

These are alloys of copper and tin and were the first to be developed about four thousand years ago. They were so important that they led to periods in time being named the Bronze Age. Wrought alloys with 4-8% tin are harder, stronger and stiffer than the wrought brasses and in strip and wire form are produced with a combination of high yield strength and good corrosion resistance which makes them ideal for use as springs. Details of the bronzes and other copper alloys used for springs may be found in the standards BS1654 'Copper and copper alloys strip for springs and connectors' and BS2B33 'Copper beryllium springs for Aerospace'.

Addition of small amounts (0.01-0.45) of phosphorus further increases the hardness, fatigue resistance and wear resistance leading to applications such as springs, fasteners, masonry fixings, shafts, valve spindles, gears and bearings. Cast phosphor bronzes with up to 10% tin and 20% lead are widely used for heavy duty bearings.

These are alloys of copper with 5 - 12% aluminium, some having additions of iron ,nickel, manganese and silicon, available in cast and wrought form. They are stronger than the brasses or tin bronzes with better corrosion resistance due to a hard, adherent, protective alumina film (Al2O3) They have an attractive golden colour, with very little tarnishing with time. The major use for aluminium bronzes is in sea water applications, such as:

• Fasteners
• Pumps and valve components
• Pipe fittings
• Heat exchangers
• Bearings

where they meet exacting Def Stan specifications (previously NES), and are widely used for MOD applications.

Silicon Bronze

These are alloys of copper with 3% silicon and 1% manganese. Silicon bronzes have a good combination of strength and ductility, good corrosion resistance and easy weldability. They are used in architectural applications such as:

• Door fittings
• Railings
• Church doors
• Window frames
• Hinges
• Wall ties
• Fastener material for marine applications,

The alloy is a firm favourite with sculptors and metalsmiths because of its workability, longevity and attractive golden bronze colour.

Manganese Bronze and Architectural Bronze

There may be confusion when brasses are incorrectly called bronze. Manganese bronze CuZn40Mn1Pb1 (CW720R) is a brass used for architectural applications where the manganese leads to the formation of an attractive chocolate brown colour. The term 'Architectural Bronze' is sometimes applied to a leaded brass CuZn41Pb1A which in service, due to the aluminium, develops an attractive golden lustre. Like all brasses these alloys combine longevity with an aesthetic appeal which improves with time and they give a feeling of luxury and prestige both inside and out to any building. They are available in all forms and are used for cladding, windows, doors and curtain walls. They are usually finished by waxing.

Publications and Software

To see all publications and software click here.

Pub 80 Aluminium Bronze Corrosion Resistance Guide
Survey of published and other information relating to aluminium bronzes in a number of environments. Recommendations are made for materials suitable for many applications. 1981. 28pp.

Pub 81 Designing Aluminium Bronze Castings
Reprint of an article published in ‘Engineering’ August 1982 (Tech file 116). The advantages of aluminium bronze casting alloys are discussed with advice on how various design criteria affect casting quality. 1983. 8pp.

Pub 82 Aluminium Bronze Alloys Technical Data
Physical and mechanical properties at low, ambient and elevated temperatures are provided for wrought and cast aluminium bronze alloys. 1981. 93pp.

Pub 83 Aluminium Bronze Alloys for Industry
Describes the properties, applications and fabrication of aluminium bronze alloys. 1986. 24pp.

Pub 85 Welding Aluminium Bronze
Describes the essential features of good welding practice in relation to the aluminium bronze alloys. 1980. 7pp.

Pub 86 Aluminium Bronze. Essential for Industry
Illustrated 8-page leaflet highlighting the main attributes of the important aluminium bronzes including selection criteria, properties, corrosion resistance, welding and machining. 1989. 8pp.

Pub 115 Aluminium Bronze with Cast Stainless Steels and Ni-resist in
Offshore Seawater Environments
This report has collated data comparing the properties of cast nickel aluminium bronze (NAB), in particular NES 747 Part 2, with cast standard and super austenitic and duplex stainless steels and Ni-Resist for use in offshore sea water applications. Properties compared are physical, mechanical and fabrication but the bulk of the work has related to the corrosion aspects of the materials. 1996. 19pp.