Mining in Cornwall and Devon tin was found as alluvial deposits of cassiterite in the gravels of stream beds. Eventually tin was mined underground; underground mines sprang up as early as the 16th century. Tin lodes were also found in outcroppings of cliffs. Tin is one of the earliest metals to have been exploited in Britain. Chalcolithic metal workers discovered that by putting a small proportion of tin (5 – 20%) in molten copper, the alloy bronze was produced. The alloy is harder than copper. The oldest production of tin-bronze is in Turkey about 3500 BC, but exploitation of the tin resources in Britain is
2219 aluminium alloy toughness, is weldable and resistant to stress corrosion cracking, therefore it is widely used in supersonic aircraft skin and structural members. The Space Shuttle Standard Weight Tank was also fabricated from the 2219 alloy. Alternate designations include AlCu6Mn and A92219. It is described in the following standards: The alloy composition of 2219 aluminium is: 2219 aluminium alloy 2219 aluminium alloy is an alloy in the wrought aluminium-copper family (2000 or 2xxx series). It can be heat-treated to produce tempers with higher strength but lower ductility. The aluminium-copper alloys have high strength, but are generally less corrosion resistant and harder to