October 20, 2013

Define Alloy? Types of Important Alloys - General Knowledge

An alloy is a mixture of two or more metals. Alloys are normally made to give a particular metal a feature that it does not have in its natural state. For instance, copper in its natural state is very soft; however, copper alloys help the metal toughen and thus give it the ability to retain its shape.  Alloys are usually synthetic materials, developed by scientists for special purposes. They generally have specially desirable properties quite different from the metals from which they are made.
Babbitt metal
tin: 90%
used in bearings because of its low measure of fricti with steel
antimony: 7%
copper: 3%
bell metal
copp 77%
casting of bells
tin : 23%
Cu(60% to 80%), Zn (40 to 20%)
inexpensive jewelry; hose nozzles and couplings; piping; stamping dies

copper with up 12% tin
coins and medals; heavy gears; tools; electrical hardware
Coin metal
copper: 75%
U.S. coins
aluminum: 95%
aircraft, boats, railroad cars, and machinery because of its high strength and resistance to corrosion
copper: 4%
manganese: <1%
magnesium: 0.5%
nickel 60%
corrosion-resistant containers
copper: 33%
iron: 7%
nickel: 80-85%
heating elements in toasters, electric heaters, etc.
chromium: 15-20%
phosphor bronze
bronze with a small amount of phosphorus
springs electrical springs, boat propellers
lead: 50%
joining two metals to each other
tin: 50%
sterling silver
silver: 92.5%
jewellery, art objects
copper: 7.5%
Type metal
lead: 75-95%
used to make type for printing because it expands as it cools
antimony: 2-18%
tin: trace
German Silver
Cu (60%), Zn (25%), Ni (15%)
For making utencils
Mg (5%), Al (95%)
For making aircraft frame
Rolled Gold
Cu(90%), Ni (10%)
For making cheap ornaments
Gun metal
Cu (85%), Zn (10%), Sn(5%)
Used for engineering purpose
Fe (98%), C (2%)
For making nails, screws, bridges
Stainless Steel
Fe (82%) Cr, Ni (18%)
for making cooking utencils, knives


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