NON-FERROUS METALS—BRONZE

P.MOHAN BHARATHYMECHANICAL

BRONZE Bronze is an alloy made of copper and

another metal, usually tin. Bronze is 88% copper and 12% tin. Bronze usually is a golden hard, brittle

metal Microstructure of the bronze

TYPES:Types of bronze Tin bronzes Aluminium bronze Silicon bronzes Beryllium bronzes

TIN BRONZES Bronzes of alloy of copper and tin. It is soluble in 1% in tin at room

temperature It is 13.5% of tin at 798oc.Plain tin bronze:Bronze and Tin containings:

Wrought iron:Alloy containing up to 8% tin

They contain only α- phase. They are absence in β phase enable to shape easily in cold working operation. These are mostly used for sheets and wires.

PLAIN TIN BRONZE:Cast alloys:Alloys containing between 8 to 12% of tin

They used for gears, machine parts and heavy load bearings.

Alloys containing between 12 to 20% of tin

They used for make bearings.

Alloys containing between 20 to 25% of tin

This type of alloys are very hard and brittle, and give ringing sound. They are used to make bells and bell metals.

TIN BRONZE

ALUMINIUM BRONZETypical composition: Copper 80% Aluminium 10% Nickel 5% Iron 5% A type of BRONZE is mixed to Al, added to copper. Small amounts ofother elements such as Fe, Mn, Ni and silicon are added for corrosion resistance.Uses:It is used in marine environment.It is used in fittings.

SILICON BRONZETypical composition: Copper 96% Silicon 3% Manganase 1% Has small amounts of silicon to allow it to be wrought or cold worked into a stronger alloy such as by rolling. Uses: It is also resistant to corrosion and therefore good for use in the marine environment.

PHOSPHOR BRONZETypical composition: Copper 94.8% Tin 5% Phosphorus 0.2%

Usually not more than 0.2% of the Phosphur is used in the metal.

Phosphor being the main alloy metal Manufacture to purify the melt and create a purer stronger type of bronze. Uses: It is very corrosion resistant and therefore good in the marine

environment.

BERYLLIUM BRONZES It is soluble in copper upto 2.1% at 870oc. In this bronze containing 3%Be. It is available in cast or wrought form.Properties:It is good corrosion resistance.It is high fatigue resistance.Uses:It is uses in gears, diaphragms and bearings.It is used in electrical conducts and moulds of forming plastics.It is high cost of Be, is not used in many properties.

LEADED BRONZETypical composition: Copper 85% Lead 5% Tin 5% Zinc 5% bronze alloy that has a small amount of lead, tin and

zinc added in similar quantities.Uses: It is good for use in the marine environment. Leaded Gunmetal of lead with bronze is used in the

weapons.

ADVANDAGES AND DISADVANDAGES: Advantages: Bronze is an alloy consisting mainly of copper but the addition of

other metals (usually tin) produces an alloy much harder than plain copper. Bronze metal fatigue better, and conducts heat and electricity, better than most steels.

Corrosion Resistance - By forming a protective surface film, most copper alloys resist many corrosive environments

Withstand High Temperatures - Several families of bronze alloys work well in elevated temperature environments

Friction and Wear - Copper alloys wear well against steel and are used in numerous bearing and gear components

Good Machinability - In general, copper alloys are easy to machine compared to steel

Weldability - Many grades can be welded Brazing and Soldering - All grades of copper alloys can be brazed and soldered

Disadvantages: Bronzes are generally softer, weaker and more expensive than steel.

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APPLICATION: Bronze was especially suitable for use in boat and ship

due to toughness and resistance to salt water corrosion. Bronze parts are tough and typically used forbearings,

clips, electrical connectors and springs Bronze is still commonly used in ship propellers and

submerged bearings. Sculptors may prefer silicon bronze because of the

ready availability of silicon bronze. Aluminium bronze widely used for cast bronze sculpture. Phosphor bronze used in guitar and piano strings

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