|Metal||able to be worked, hammered, or shaped under pressure or blows without breaking|
|Specific gravity||a substance of a physical state in which it does not resist change of shape but does resist change of size|
|Alloy||a chemical element, such as iron or gold, or a mixture of such elements, which is generally hard and strong and which electricity and heat can travel through|
|Liquid||the ratio of the density of a substance to that of water|
|Malleable||a metallic material such as steel, brass or bronze, consisting of a mixture of two or more metals or non-metals|
Exercise 5. Fill in the gaps in the table.
Exercise 6. Agree or disagree with the statements.
|1. Mercury is not solid at room temperature.|
|2. Most metals are not malleable.|
|3. Carbon is a tough metal.|
|4. Calcium is very important for the human body.|
|5. Silver doesn’t conduct electricity and heat very well.|
|6. Iron is a recently discovered metal.|
|7. Metallic luster is a characteristic of non-metals.|
|8. Gold is the most malleable and ductile yellow metal|
Exercise 7. Translate the following sentences from Russian into English.
A. К металлам относят вещества, обладающие следующими физическими свойствами: прочностью и пластичностью, тепло- и электропроводностью, характерным светлым цветом. Металлы хорошо проводят электрический ток, но с увеличением температуры их сопротивление 1 возрастает.
B. В твердом состоянии металлы обычно имеют кристаллическое строение 2, и большинство из них хорошо сплавляются в любых соотношениях.
C. Ряд металлов (всего их 19) и их сплавов обладают важным для техники будущего свойством сверх проводимости 3.
D. Часть очень чистых металлов оказалась плохими проводниками и была отнесена к классу полупроводников.
2. Crystalline structure
Exercise 8. Give English equivalents to:
Металл, руда, сталь, химия, сплав, изменение, марганец, углерод, плотность, газ;
Жидкий, прочный, пластичный, ковкий, твердый, электроположительный, чистый;
Подвергать, сплавлять, очищать, обрабатывать, формировать, зависеть, нагревать.
Exercise 9. Translate the following words into Russian. Pay attention to the Parts of Speech.
Certain – certainly; physics – physical; pure – purification; long – to elongate; product – production – to produce; to adjust – adjustment; short – shortage; to treat – treatment; strong – strength; hard – to harden; to relate – relative – relatively; to differ – different – difference.
Exercise 10. Say what do you know about (i) steel, (ii) steel-making process, (iii) steel-making enterprises in Udmurtia, (iv) the role of Russia in world’s steel production. Give your answer in the form monologue / dialogue / group presentation.
Text 2. Iron and Steels
Iron is an incredibly useful substance. It's less brittle than stone yet, compared to wood or copper, extremely strong. If properly heated, iron is also relatively easy to shape into various forms, as well as refine, using simple tools. There certainly aren't any iron shortages to worry about. The Earth's crust is 5 percent iron, and in some areas, the element concentrates in ores that contain as much as 70 percent iron.
Very pure iron is prepared by reducing ferric oxide with hydrogen at 1,000 degrees C or by vacuum melting of a product obtained by electrolysis of ferrous ammonium sulphate solution. Chemically pure iron is produced by thermal decomposition of iron pentacarbonyl at 200 to 250 degree C, when iron is deposited as a fine powder.
Physical Properties of Iron. Pure iron is a grayish-white soft metal. Its melting point and boiling point are 1,538 degree C and 2,735 degree C respectively. Pure iron is malleable and ductile and does not harden on quenching. It is more magnetic than any other metal, and its magnetic properties remain unaffected even at a very high temperature. Iron is a good conductor of heat and electricity.
Pure iron exists in three allotropic forms, depending on temperature. These are distinguished as α-, γ- and δ-iron respectively. These differ in their thermal stability, crystal structure, hardness, magnetic properties and in their ability to dissolve carbon.
Chemical Properties of Iron. Pure iron is unaffected by dry air and pure water at ordinary temperature, but commercial iron rusts in moist air and water. Pure iron gives off hydrogen, nitrogen and carbon monoxide on heating. The metal burns brilliantly when heated in oxygen and also undergoes combustion in burning sulfur. It decomposes steam at red heat, which is utilized in the manufacture of hydrogen.
Steel is the most important form of commercial iron. Steel is manufactured by blending carbon and iron in a specified ratio, where the normal percentage of carbon ranging from 0.2 to 2.14 per cent of the total weight. Apart from carbon, the other alloying materials used in the production of steel include manganese, chromium, tungsten and vanadium which impart desired properties to the steel. This metal has a wide range of properties.
The properties of steel are related to the carbon content and heat treatment. The carbon content usually ranges from 0.25 to 2 percent. As the percentage of carbon is increased, the tensile strength of the steel also enhances, but the ductility drops. Steel with 2 percent carbon resembles "cast iron" in being hard and brittle. On the other hand, steel containing a small proportion of carbon is soft and ductile like "wrought iron," and is called "mild steel."
The melting point of steel varies from 1,298.89 to 1,500 degree C. If steel is heated to redness and quenched in cold water, it gets very hard and brittle, and the product is known as "quenched steel." If this is again heated in between 200 to 300 degree C and allowed to cool slowly, the steel recovers its elasticity to some extent. This process is known as "tempering." By adjusting the temperature of tempering, steel of any desired degree of hardness can be produced. The surface color of steel changes according to temperature due to the presence of a thin oxide film during tempering. For instance, heating it to 230 degree C produces a pale yellow color, while an intense blue color is formed by heating to 300 degree C.
Special and Alloy Steels. Silicon, titanium, vanadium, molybdenum, chromium, manganese, tungsten, nickel and cobalt are used in the production of special steels with desired physical and mechanical properties. Sometimes, more than one of these elements is used. They are generally added to the melt steel in an electric furnace. For example:
· Silicon steel containing about 3.5 percent silicon and very little carbon is employed for making electromagnets and transformers.
· The presence of 2 percent of chromium in steel makes it very tough, suitable for ball-bearings and armor plates.
· Stainless steel contains about 12 to 15 percent chromium, and is resistant to the action of organic acids.
Application. Steel is extensively employed for structural purposes, for making tools, machineries, railroads and domestic articles. It is also used for making bar magnets, magnetic needles, armor plates, razors, knives, swords, watches and springs.
|Substance – вещество To heat- нагревать Shortage – нехватка, недостаток Earth's crust – земная кора ferric oxide – оксид железа (III) melt – плавить ferrous ammonium sulphate solution – раствор сернокислой закиси железа и амония decomposition – разложение, распад iron pentacarbonyl – пентакарбонил железа soft – мягкий melting point – точка (температура) плавления boiling point – точка кипения quenching – закалка allotropic form – аллотропическая модификация to dissolve – растворять To rust- ржаветь moist air – влажный воздух combustion – горение, сжигание Steel – сталь specified ratio – установленное соотношение||manganese – марганец tungsten – вольфрам to impart – передавать heat treatment – термообработка tensile strength – прочность на растяжение to enhance – усиливать, увеличивать cast iron – чугун wrought iron – ковкий чугун mild steel – малоуглеродистая сталь quenched steel – закаленная сталь elasticity - упругость to some extent – до некоторой степени tempering – нормализация oxide film – оксидная пленка Silicon – кремний electric furnace – электрическая печь Tough – вязкий, прочный ball-bearing – шариковый подшипник armor plates – броневая плита Stainless steel – нержавеющая сталь organic acid – органическая кислота|
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