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Answer the following questions:

  1. What are the raw materials for the production of copper?

  2. Why must all copper ores be concentrated by flotation?

  1. Whаt purpose is pure copper chiefly used for?

  2. What properties does the alloying of copper with other elements increase?

  3. What main groups do copper alloys comprise?

  4. What alloys of copper are called bronzes?

  1. Into what groups are bronzes divided?

  2. Why are aluminium bronzes frequently used in foundry practice?

Titanium and its alloys

As an engineering material titanium has been widely applied only in the last years.

Titanium is a silvery-white metal which melts at approximately 1668°C and has a specific gravity of 4.505. Commercially pure titanium possesses high strength prop­erties. The tensile strength of most titanium alloys ranges from 100 to 140 kg/mm2, in conjunction with high elongation.

The hardness, tensile strength and yield point of tita­nium are increased with the degree of cold deformation. The elongation value drops rapidly when the degree of cold deformation (reduction) exceeds 50 per cent and becomes equal to 10 per cent. Impurities found in com­mercial titanium can be divided into two groups: elements which form interstitial solid solutions with titanium (O2, N, C and H2) and elements which form substitution solid solutions (Fe and other metallic elements). The first have a much greater effect on the mechanical properties than those in the second group.

Even very small amounts of oxygen and nitrogen in titanium alloys sharply reduce the ductility. A carbon content of more than 0.2 per cent reduces both the ductility and impact strength of a titanium alloy. It is supposed that the brittleness of titanium is a result of strain ageing and is connected with the presence of dissolved hydrogen in the beta-phase.

Titanium and its alloys are hardened either by a sur­face heat treatment followed by ageing at 400°—500° C or by producing a case which contains nitrogen, carbon and boron Industrial titanium alloys contain vanadium, molybdenum, chromium, manganese, aluminium, tin, iron or other elements, singly or in various combinations.

A combination of high mechanical properties with low specific weight and excellent corrosion resistance enables titanium to be used in building supersonic air craft.

Answer the following questions:

  1. What is titanium?

  2. What does the hardness, tensile strength and yield point of titanium depend upon?

  3. Do very small amounts of oxygen and nitrogen in titanium alloys reduce the ductility?

  4. How are titanium and its alloys hardened?

  5. What constituents do industrial titanium alloys contain?

Литература

  1. Алехина М.С. Английский для металлургов. М.: Русский язык, 2005.

  2. Андреев Г.Я., Гураль Л.Л., Лев А.Л. Сборник технических текстов на английском языке. М.: Издательство «Высшая школа», 1972.

  3. Иллюстрированный словарь английского и русского языка с указателями. М.: Живой язык, 2003.

  4. Парахина А.В. Пособие по переводу технических текстов с английского языка на русский. М.: Издательство «Высшая школа», 1972.

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