Методические указания и контрольное задание №5 по английскому языку для студентов заочного факультета специальностей 170600, 170700, 120100, 120200. Доржиева Г.Б - 9 стр.

   9. make up(n) – состав                                               shaping the moulding sand around a pattern which is to have the
   10. green sand – влажный песок                                       same shape as the finished object, but their size should be a little
                                                                        larger as the steel casting shrinks while cooling. Moulding sand
                               Steel                                    is to be mixed with water in a certain proportion. Many of the
                                                                        smaller steel castings are used as they come from the moulds,
  1. Steel is a ferrous material with some carbon content. There        but most of the larger ones have to be annealed to relieve the
are two kinds of steel: carbon and alloy steel. Carbon steels are       cooling strains formed when the metal solidifies. Steel can be
the most common steels used in industry, their properties               used for a great variety of castings, and it can be cast into very
depending only on the percentage of carbon they contain.                large bodies.
Machine steels are very soft and can be used for making machine
parts that do not need strength. Medium carbon steels are better        II. Match the following words and definitions.
grade and stronger than machine steels. Tool steel may be used
for manufacturing tools and working parts of machines because           1) content             a) making something in
of its high strength and hardness.                                       2) strength           b) to make or become hard
   2. Alloy steels are those in which in addition to carbon an          3) solidify            c) quality of being strong
alloying element is present in some appreciable quantity. They          4) obtain              d) substance
are divided into special alloy steels and high-speed steels which,      5) moulding            e) to get
in turn, are called "self-hardening steels". Alloying elements of
these     steels     are:     nickel,    chromium,       manganese,     III. Vocabulary in Context.
molybdenum, tungsten, vanadium, etc.                 These alloying       Choose the definition that fits each word or phrase as it is
elements have a definite effect on the characteristic of the steel;     used in the text.
nickel increases its strength and hardness; a high percentage of
chromium makes steel rust-resistant and in this case it is called       1. differ              2. shrink
"stainless steel". The addition of some tungsten and molybdenum         a. be unlike           a. to become less
gives heat-resistant steel.                                             b. amount              b. to move back
  3. Vanadium makes steel corrosion, shock and                          c. disagreement        c. process
vibration-resistant. The sand used for making moulds for steel
castings differs greatly from that used in other branches of            3. escape              4. increase
moulding. It must be much more refractory and open grained,1            a. distraction         a. To become greater in degree
because the metal is poured at an extremely high temperature and        b. to get free         b. growth
solidifies very rapidly. If the sand is not refractory enough it will   c. to forget           c. be destroyed
fuse with the metal. The sand being not open grained, the gases
will not escape from the mould rapidly enough, and blowholes            IV. Put these words in the right order to make up a sentence.
will be formed in the casting. Many good steel castings are             1. common/ steels/ are / carbon/ the / steels/ most/ used/ in/
obtained with green sand moulds. Sand moulds are made by                   industry.