- •Методическое пособие
- •Пояснительная записка
- •Unit 1. Metallurgy some words about metallurgy
- •Notes and commentary
- •Exercises
- •Find in the text the English equivalents of these Russian word combinations.
- •Answer the questions.
- •Unit 2. Physical properties of metals and alloys
- •Notes and commentary
- •Exercises
- •Answer the questions.
- •Match the term with its definition.
- •Find in the text sentences containing the following words and translate them into Russian.
- •Find 13 words on the topic in the crossword-puzzle and give their Russian equivalents.
- •Unit 3. Mechanical properties of metals and alloys
- •Notes and commentary
- •Exercises
- •Make words out of these letters and translate them into Russian.
- •Name the property according to its definition.
- •Make up definitions out of these words and name the property.
- •Finish the sentences according to the text.
- •Unit 4. Foundry equipment.
- •Foundary metal casting
- •Notes and commentary
- •Exercises
- •Learn the words and special terms on foundary.
- •Answer the questions.
- •Write the English equivalents of these Russian words and make up sentences of your own with them.
- •Notes and commentary
- •Exercises
- •Read the sentences and say whether they are true or false.
- •Make up sentences out of these words.
- •What is the Russian for these words and word combinations?
- •Notes and commentary
- •Exercises
- •Say what type of machine does this or that operation.
- •Describe the work done by every machine. Unit 7. Casting metals
- •Notes and commentary
- •Exercises
- •Answer the questions.
- •Find the sentences with these words in the text and translate them into Russian.
- •Unit 8. Types of furnaces.
- •D iagram of a Foundary Cupola for Melting Cast Iron notes and commentary
- •Notes and commentary
- •The bessemer converter
- •Notes and commentary
- •The open hearth furnace
- •The electric furnace
- •Unit 9. Metals and their alloys.
- •Answer the following questions:
- •Magnesium and its alloys
- •Answer the following questions:
- •Copper and its alloys
- •Answer the following questions:
- •Titanium and its alloys
- •Answer the following questions:
- •Литература
Unit 9. Metals and their alloys.
Task for selfstudy:
read the texts
write down all special terms to each of the texts
answer the questions
make a report on any metal you like
ALLOYS
Pure metals are comparatively seldom used; in engineering, application is made chiefly of alloys which consist of two or more metals, or of metals and metalloids.
Alloys are metallic solids, complex in composition, formed as a result of the freezing of the melt — the liquid solution of two or more metals, or metals and metalloids.
Each constituent of an alloy is called a component. Alloys may be binary (two-component), ternary (three-component), etc.
The ability of various metals to form alloys differs greatly and, therefore, the structure of various alloys after solidification may also be very diverse.
In the liquid state, alloys are entirely homogeneous and from the physical point of view constitute a single phase. Nonhomogeneity may appear when an alloy is transformed from the liquid to the solid state, i.e. several solid phases are formed. After solidification, alloys may consist of one, two or more phases depending upon the nature of their components. Certain metals are not mutually soluble in the liquid stale; they form two layers with different specific weights (e.g., lead and iron, lead and zinc, etc.). It is difficult to form an alloy in such cases since it is necessary to mix the metals into each other.
ALUMINIUM AND ITS ALLOYS
Next to oxygen, aluminium is the most abundant element in nature: about 7.45 per cent of the earth's crust consists of aluminium.
Aluminium is extracted from rock with a high alumina content. The most important sources are bauxite, kaolin, nepheline and alunile.
Bauxite is the principal source of aluminium. The less silica in a bauxite the higher its quality as an aluminium ore. Kaolin clays are very abundant in nature but the extraction of aluminium from these ores presents difficulties due to the considerable amount of silica present.
The most important properties of aluminium are its low specific gravity (2.7), high electrical and thermal conductivities, high ductility, and corrosion resistance in various media.
Pure aluminium has only few applications; it is used for the manufacture of electrical wire, chemical apparatus, household utensils and for coating other metals.
Aluminium alloys are more widely used in industry. Wrought aluminium alloys have a high mechanical strength which in some cases approaches the strength of steel. Wrought aluminium alloys are further classified as non-heat-treatable and heat-treatable alloys. .Wrought aluminium alloys also include complex alloys of aluminium with copper, nickel, iron, silicon and other alloying elements. Complex wrought aluminium alloys of the duralumin (dural) type and certain others have found most extensive application in many industries.
Several grades of duralumin are available in the Russia. They are identified by the Russian letter Д followed by a figure indicating the number of the alloy in the series. Duralumin, grade Д-1 can be obtained in the form of sheets, bar stock and tubing; grades Д-6 and Д-16 аre usually produced in the form of bars, and grade Д-ЗП is made as wire for rivets.