metals fall into 3 basic categories ~ Ferrous, Non-ferrous and Alloys.
metals are composed primarily of Iron (chemical symbol Fe, hence ferrous),
non-ferrous metals are not.
For the purposes
of this course you only need to be aware of Cast Iron.
The following is a list of "pure", non-ferrous metals. In fact most of them are useless in their pure form and will often contain traces of other elements to improve their characteristics. The point at which they become classified alloys is a bit hazy but they are not regarded as alloys.
~ Malleable, ductile, low density, corrosion resistant.
There is only one ferrous alloy that you need to concern yourself with and that is Steel. It is obtained by alloying Iron with Carbon although the quantities of Carbon involved are small.
Steel < 0.3% Carbon
90% of the
steel produced is Low-Carbon or Mild Steel. The lower the Carbon content,
the greater the ductility. A higher Carbon content will increase the strength
at the cost of ductility.
+ 18% Tungsten ~ High Speed Steel (Lathe, milling cutters)
The purpose of an alloy is to change one or more of the properties of a material. This is particularly the case for Aluminium which in its pure state does not have the strength-to-weight ratio required for aircraft construction.
There are 2 non-ferrous metals which are commonly alloyed. Copper and Aluminium.
+ Zinc 40% ~ Brass, which has greatly improved strength characteristics
over Copper but with no great reduction in conductivity.
Aluminium 96% + Copper 4% ~ Duralumin, a higher tensile strength and improved strength to weight ratio version of Aluminium.
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