Вступ до методичних рекомендацій

Ex.13. Answer the following questions:

1. 
   What are the main characteristics of non – ferrous metals?
   
2. 
   What are the properties of copper and what is it used for?
   
3. 
   What purposes is aluminium used for?
   
4. 
   What metals are used for producing non – ferrous castings?
   
5. 
   What do you know about brasses?
   
6. 
   What do you know about bronzes?
   
7. 
   What are the main properties of non – ferrous castings?
   
8. 
   Why are attempts made to replace non – ferrous metals by ferrous ones?
   

Ex. 14. Complete the table. Use the information from the text A
Non – ferrous metals

	Copper	Aluminium	Bronze	Aluminium alloys
Appearance	Reddish brown tough metal
Qualities	High electric conductivity
Used for	Wires, pipes, telephone cables

V. Oral Practice


Ex. 15. Speak on the topic “Non-ferrous metals” using the table of ex.14


Ex. 16. Prove that non ferrous metals are very important.
VI. Reading and comprehension


Ex.17. Read the text without a dictionary for 5 minutes and define the quality of the aluminum and the processes which improve its quality.


Aluminium
Aluminium, lightweight, strong, and readily formable. Aluminium and its alloys, numbering in the hundreds, are available in all common commercial forms. Because of their high thermal conductivity, many aluminium alloys are used as electrical conductors.
Commercially pure aluminium has a tensile strength of about 13, 000 psi. Cold-working the metal approximately doubles its strength. For greater strength aluminium is alloyed with other elements such as manganese, silicon, copper, magnesium or zinc. Some alloys are further strengthened and hardened by heat treatments. Most aluminium alloys lose strength at elevated temperatures, although some retain significant strength to 500 ⁰F.
Aluminium is produced by electrolytic means from bauxide, an aluminium hydroxide, and makes a good clean casting with a fairly coarse grain structure. It is a fair substitute for cast iron except that it is a bit more ductile. On the other hand, it can be rolled or drawn into sheets, rods, and tubes that can be bent due to their ductility whereas cast iron cannot.
The aluminium alloys with copper, manganese, silicon and nickel are pretty numerous and are selected either for their corrosion resistance, high electrical conductivity, ductility and /or higher strength.

Supplementary Reading
Texts for written translation with a dictionary
Read the texts and translate them in writing. Use a dictionary.


Introduction to nonferrous metallurgy

Although ferrous alloys are specified for more engineering applications than the non ferrous metals, the nonferrous metals offer a wider variety of characteristics and mechanical properties. Availability, abundance, and the cost of converting the metal into useful forms all play important parts in selecting a nonferrous metal. One ton of earth contains about 180 pounds of the most abundant metal on land, aluminium. One on of sea water contains more magnesium than any other metal. All sources combined, magnesium is the most abundant metal on earth. But because magnesium is difficult to convert to a useful metal, it costs several times that of the least – expensive and most easily produced metal, iron.

Although nearly 80% of all elements are called “metals”, only about two dozen of these are used as structural engineering materials. Of the balance, however, many are used as coatings, in electronic devices, as nuclear materials, and as minor constituents in alloys.


Specify – визначати, установлювувати
Magnesium - магній