Springs are elastic objects which are used to store mechanical energy.
There are different types of springs but they are all usually made from hardened steel.
Some types of non-ferrous metal are also used including: o    Titanium : Phosphor bronze : Beryllium copper Springs made from these non-ferrous metals are used in parts requiring corrosion resistance, and beryllium copper is particularly good for use in parts that carry electrical currents because of its low electrical resistance.
Small springs can be manufactured from pre-hardened metals, while larger springs are generally made from annealed steel which is hardened after fabrication.
Depending on the required operating environment and design, many different materials can be used to make springs, as long as the material has the required combination of elasticity and rigidity.
Springs are classified according to their properties, and depending on the load they may be classified as: o    Torsional spring o    Compression spring o    Tension or extension spring Depending on the material used in the construction of the spring it may be classified as: o    Flat spring : Wire or coil spring Some common types of spring can include: o    Hairspring or balance - used in watches, galvanometers o    Cantilever spring - a spring which is fixed only at one end o    Coil spring - made by winding a wire around a cylinder o    Volute spring - a cone shaped compression spring.
Under pressure the coils are not forced against each other allowing longer travel o    Leaf spring - a flat springy sheet used in vehicle suspensions Springs are used in many different industries such as the aircraft industry, the engineering industry and the automobile industry, and they play an extremely important role in the many facets of today's technology.