Engineering MOSAIC. Мантатова С.С - 28 стр.

UNIT XXII                                                                 because it has large grains acting like small magnets. The addition of
Metals                                                                    chromium gives extra strength and corrosion resistance, so we can
Before you start                                                          get rust-proof steels. Heating in the presence of carbon or nitrogen-
1. Why are metals essential in today’s life?                              rich materials is used to form a hard surface on steel (case-
Reading                                                                   hardening). High-speed steels, which are extremely important in
2. Read the text and find answers to the questions below:                 machine-tools, contain chromium and tungsten plus smaller amounts
  1. What equipment and materials are needed to extract iron from         of vanadium, molybdenum and other metals.
     iron ore?                                                            Vocabulary
  2. How is steel made?                                                   3. Match the words from the text with the meanings (1-7) below:
  3. How does different inclusion of other elements influence the         a. mine                 1. the ore from which aluminum is made
     properties of the steel?                                             b. furnace              2. baked clay
                               Metals                                     c. process              3. to dig a hole in order to obtain something
       1. If you look around you, you will see that many of the things    d. brick                4. extremely large
we use in our daily life have metal in them. Metals are substances        e. bauxite              5. an enclosed space in which a hot fire is
that are mined from the earth where they were formed a long time                                  made to extract metals from ores
ago. When metals are mined, they are found mixed with rocks and           f. giant                6. a rock from which metal can be obtained
earth in a form called ore. The most common ores are iron and             g. liquid               7. a substance which is not a solid or a gas
bauxite. Aluminum, a metal used for many household objects, is            h. ore                  8. a connected set of actions which are carried
made from bauxite. There are as many as seventy different kinds of                                out to obtain a particular result
metals, but iron is the most commonly used. After iron ore is mined       Speaking and Writing
the rocks and dirt must be separated from the metal. This process is      4. Arrange the following sentences according to the process of
called smelting and is done by heating the ore in giant blast furnaces.   melting described in the text:
       2. The ore is placed in a steel furnace which is lined with           1 The liquid iron is poured out into a mold to cool and become
bricks. Then a special kind of coal, called coke, is added along with            solid.
limestone. Hot air is forced into the furnace, heating the mixture to        2 The ore is put in a steel furnace.
1.600 degrees centigrade. The metal in the ore becomes liquid and            3 A coke is added with limestone.
sinks to the bottom. Other substances rise to the top and are skimmed        4 The metal in the ore becomes liquid and sinks to the bottom.
off. These waste products are called slag and are worthless. The             5 Hot air is forced into a furnace.
liquid iron is then poured out into a mold to cool and become solid.         6 Slag rises to the top and is skimmed off.
Later, it can be heated again and molded to make useful items. If it is   5. Make up a report on how metals are produced using the following
to be made into steel, iron is melted again and mixed with carbon in         clichés:
another careful process. There are many kinds of steel, and the              1. First iron ore is mined.
process for making each kind is different.                                   2. Then … / Secondly … .
       3. The inclusion of other elements affects the properties of the      3. After that … / Thirdly… .
steel. Manganese gives extra strength and toughness. Steel containing        4. Later… .
4 per cent silicon is used for transformer cores or electromagnets           5. In the end … / Finally … .