This document discusses different types of engineering materials, including metals and non-metals. It describes how metals can be divided into ferrous and non-ferrous categories, with ferrous metals containing iron like cast iron and steel, the two most important ferrous metals. It also notes that certain elements can be added to steel to improve its properties. The document then explains that plastics and ceramics are examples of non-metals, with plastics categorized as thermoplastics and thermosets, and ceramics used when materials need to withstand high temperatures.
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3. Engineers have to know the best and
most economical materials to use.
Engineers must understand the
properties of these materials and how
they can be worked. There are two
kinds of material used in engineering
– metals and non metals.
4. We can divide metals into ferrous and
non ferrous metals. The former
contain iron and the letter do not
contain iron. Cast iron and steel,
which are both alloys, or mixture of
iron and carbon, are the two most
important ferrous metals. Steel
contains a smaller proportion of
carbon than cast iron contains.
5. Certain elements can improve the
properties of steel and are therefore
added to it. For example,
chromium may be included to
resist corrosion and tungsten to
increase hardness. Aluminum,
copper, and the alloys, bronze and
brass, are common non-ferrous
metals.
6. Plastics and ceramics are non metals,
however, plastics may be machined
like metals. Plastics are classified into
two types – thermoplastics and
thermosets. Thermoplastics can be
shaped and reshaped by heat and
pressure but thermosets cannot be
reshaped because they undergo
chemical changes as they harden.
Ceramics are often employed by
engineers when the materials which
can withstand high temperature are
needed.
