In studying engineering process an engineer who is to built a machine must select suitable materials for each machine member. One must know the characteristics of engineering materials. These are as follows: strength, stiffness, ductility, toughness, elasticity, fatigue resistance, shock resistance, corrosion resistance, wear resistance, hardness resistance, frictional qualities, machinability, casting and forging properties. They depend upon the chemical composition and the physical structure of the material. From the point of tonnage produced and used, iron is the world’s most common metal, followed in turn by copper, zinc, lead and aluminium. Cast iron is a general term applied to iron-carbon alloys containing more than 1.7 per cent of carbon. Cast iron without the addition of alloying elements is weak in tension and shear, strong in compression and has low resistance to impact. It is obtained from the cupola furnace where pig iron is remelted in contact with coke. Grey cast iron has the carbon present in the free or graphite state and is soft, easily machined, and only moderately brittle. Malleable cast iron is made by heating white iron castings for a period of several days in airtight pots filled with an oxide of iron. Steel is a ferrous material with a carbon content from 0.1 to 1.0 %. Semisteel is a name to a metal made by melting 20 to 40 % of steel scrap with cast iron in the cupola. Steel castings are more expensive but stronger and tougher. Wrought iron is quite ductile and can be easily rolled, drawn, forged and welded. It has high resistance to corrosion. The carbon content is generally less than 0,1 % and the material must contain not less than 1 % of slag. Cast steel normally contains about 0,5 % of carbon, and is used to replace cast iron when castings of considerable strength are required. Forged steel is steel that has been hammered, drawn, pressed or rolled in the process of manufacturing a particular part. 2. Найдите в тексте ответы на следующие вопросы и на английском языке запишите ответы: 1. What are the characteristics of engineering materials? 2. What do they depend upon? 3. What is the most common metal? 4. What are the properties of cast iron? 5. What is cast iron obtained from? 6. What is grey cast iron? 7. What is white cast iron? 8. What is steel? 9. How is semisteel made? 10. What can you say about wrought iron? 11. What does cast steel normally contain? 12. What is forged steel?

Here are the answers in English, with brief references to the text for each item. 1) What are the characteristics of engineering materials? - Strength, stiffness, ductility, toughness, elasticity, fatigue resistance, shock resistance, corrosion resistance, wear resistance, hardness resistance, frictional qualities, machinability, casting and forging properties. (From: “They are as follows: strength, stiffness, ductility, toughness, elasticity, fatigue resistance, shock resistance, corrosion resistance, wear resistance, hardness resistance, frictional qualities, machinability, casting and forging properties.”) 2) What do they depend upon? - They depend upon the chemical composition and the physical structure of the material. (From: “They depend upon the chemical composition and the physical structure of the material.”) 3) What is the most common metal? - Iron. (From: “iron is the world’s most common metal.”) 4) What are the properties of cast iron? - Cast iron is an iron-carbon alloy containing more than 1.7 percent carbon; without alloying elements, it is weak in tension and shear, strong in compression, and has low resistance to impact. (From: “Cast iron is a general term applied to iron-carbon alloys containing more than 1.7 per cent of carbon. Cast iron without the addition of alloying elements is weak in tension and shear, strong in compression and has low resistance to impact.”) 5) What is cast iron obtained from? - It is obtained from the cupola furnace where pig iron is remelted in contact with coke. (From: “It is obtained from the cupola furnace where pig iron is remelted in contact with coke.”) 6) What is grey cast iron? - Grey cast iron has the carbon present in the free or graphite state and is soft, easily machined, and only moderately brittle. (From: “Grey cast iron has the carbon present in the free or graphite state and is soft, easily machined, and only moderately brittle.”) 7) What is white cast iron? - White cast iron is the material used to make malleable cast iron; malleable cast iron is made by heating white iron castings for several days in airtight pots filled with an oxide of iron. (From: “Malleable cast iron is made by heating white iron castings for a period of several days in airtight pots filled with an oxide of iron.”) 8) What is steel? - Steel is a ferrous material with a carbon content from 0.1 to 1.0%. (From: “Steel is a ferrous material with a carbon content from 0.1 to 1.0 %.”) 9) How is semisteel made? - Semisteel is made by melting 20 to 40 percent of steel scrap with cast iron in the cupola. (From: “Semisteel is a name to a metal made by melting 20 to 40 % of steel scrap with cast iron in the cupola.”) 10) What can you say about wrought iron? - Wrought iron is quite ductile and can be easily rolled, drawn, forged and welded; it has high resistance to corrosion; the carbon content is generally less than 0.1 percent and the material must contain not less than 1 percent of slag. (From: “Wrought iron is quite ductile and can be easily rolled, drawn, forged and welded. It has high resistance to corrosion. The carbon content is generally less than 0,1 % and the material must contain not less than 1 % of slag.”) 11) What does cast steel normally contain? - Cast steel normally contains about 0.5 percent carbon. (From: “Cast steel normally contains about 0,5 % of carbon.”) 12) What is forged steel? - Forged steel is steel that has been hammered, drawn, pressed or rolled in the process of manufacturing a particular part. (From: “Forged steel is steel that has been hammered, drawn, pressed or rolled in the process of manufacturing a particular part.”)