Birmabright on:
[Wikipedia]
[Google]
[Amazon]
Birmabright is a trade name of the former Birmetals Co. (Birmabright works in Clapgate Lane, Quinton, 
Birmabright is best known as the material used in the body of the
Birmingham
Birmingham ( ) is a city and metropolitan borough in the metropolitan county of West Midlands in England. It is the second-largest city in the United Kingdom with a population of 1.145 million in the city proper, 2.92 million in the We ...
, UK) for various types of lightweight sheet metal in an alloy
An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductili ...
of aluminium
Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It ha ...
and magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ...
. The alloy was introduced by the Birmid Group in 1929 and was particularly noted for its corrosion resistance. Birmal Boats was created in 1930 for the building of light-alloy boats. Birmetals Ltd was formed in 1936 and during the war produced both copper bearing aluminium alloys and the Birmabright magnesium bearing alloys, mainly for aircraft production.
The constituents were from 1% to 7% magnesium, with <1% manganese
Manganese is a chemical element with the Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of ...
, and the remainder aluminium. The alloys were provided in different temper conditions. e.g. soft, 1/4 hard, 1/2 hard and were designed to be work hardened e.g. by cold pressing into shape. They do not exhibit age hardening, or have a precipitation heat treatment to promote hardening (unlike other contemporary aluminium alloys such as Duralumin
Duralumin (also called duraluminum, duraluminium, duralum, dural(l)ium, or dural) is a trade name for one of the earliest types of age hardening, age-hardenable aluminium alloys. The term is a combination of ''Dürener'' and ''aluminium''.
Its ...
). Weldability is good but machinability is only fair to poor. The alloy has good seawater corrosion resistance (unlike Duralumin
Duralumin (also called duraluminum, duraluminium, duralum, dural(l)ium, or dural) is a trade name for one of the earliest types of age hardening, age-hardenable aluminium alloys. The term is a combination of ''Dürener'' and ''aluminium''.
Its ...
).
Birmetals Ltd Birmabright grades included the following : Woldman's Engineering Alloys, John P Frick, ASM International, Jan 2000.
The Birmabright designations are obsolete, but equivalent grades exist, for example BB2 equivalent specifications are British standard NS4, American 5251 and ISO designation AlMg2.
Gas welding of Birmabright is easier than that of pure aluminium and may be carried out autogenously using scraps of the same material as a filler rod.
Birmabright is best known as the material used in the body of the Land Rover
Land Rover is a British brand of predominantly four-wheel drive, off-road capable vehicles, owned by multinational car manufacturer Jaguar Land Rover (JLR), since 2008 a subsidiary of India's Tata Motors. JLR currently builds Land Rove ...
from its launch in April 1948, and in a few other classic British vehicles. The doors, boot lid and bonnet of most Rover P4 models were also Birmabright, however towards the end of production this was changed to steel to reduce costs. An early use in the 1930s was for the bodywork of the land speed record
The land speed record (or absolute land speed record) is the highest speed achieved by a person using a vehicle on land. There is no single body for validation and regulation; in practice the Category C ("Special Vehicles") flying start regul ...
car, Thunderbolt
A thunderbolt or lightning bolt is a symbolic representation of lightning when accompanied by a loud thunderclap. In Indo-European mythology, the thunderbolt was identified with the 'Sky Father'; this association is also found in later Hel ...
. Also used for the bodywork of Bluebird K7
''Bluebird K7'' is a jet engined hydroplane which Britain's Donald Campbell set seven world water speed records between 1955 and 1967. ''K7'' was the first successful jet-powered hydroplane, and was considered revolutionary when launched i ...
used for the Coniston speed record attempt by Donald Campbell.
The well known Laurent Giles designed 46ft sailboat ''Beyond'' was built of riveted sheets of Birmabright and circumnavigated in the early 1950s by Tom and Ann Worth. The hull proved corrosion resistant but required re-riveting later due to crystallisation of the rivet heads, and lasted well until being sunk in the Caribbean as an artificial diving reef in the 1980s.
Birmetals (part of the Birmid Qualcast Group) closed its factory in 1980 after losing money in 1977-1979, followed by a protracted strike over wages by key staff which prevented production.
See also
*Magnalium
Magnalium is an aluminium alloy with 5% magnesium and 95% aluminum.
Properties
Alloys with small amounts of magnesium (about 5%) exhibit greater strength, greater corrosion resistance, and lower density than pure aluminium. Such alloys are also mo ...
References
Aluminium–magnesium alloys Aluminium alloys Aerospace materials Land Rover vehicles {{Alloy-stub