- •Кафедра іноземних мов
- •Кафедра іноземних мов
- •Unit 1 (Total Score – 76 points) working sheet metal
- •Working Sheet Metal (Score – 6 points)
- •(Total Score – 76 points) unit 2 (Total Score – 71 points) rivets and riveting
- •I. Read and memorize the following words: (Score – 41 points)
- •Rivets and Riveting
- •I I. Match the words in a with the definition in b (Score – 4 points)
- •Unit 3 (Total Score – 64 points) forging processes ( I )
- •Forging Processes (I)
- •Unit 4 (Total Score – 67 points) forging processes ( II )
- •I. Read and memoraze the following words: (Score – 31 points)
- •Forging Processes (II) (Score – 6 points)
- •Beaten Metal work (Score – 6 points)
- •III. Match the words in a with the definition in b (Score – 3 points)
- •Part II. Texts for reading
- •The Importance of Forging in Machine Building
- •Uniт 2 (Total Score – 18 points
- •Classification of Steels
- •Unit 3 (Total Score – 14 points)
- •Unit 4 (Total Score – 16 points)
- •Unit 5 (Total Score – 15 points)
- •Unit 6 (Total Score – 36 points)
- •Safety Engineering in Forge Furnace Operation
- •Unit7 (Total Score – 21 points)
- •Heating by Electric Current
- •Unit8 (Total Score – 17 points)
- •Drop-Forging Methods
- •Uniт 9 (Total Score – 15 points)
- •The Drop-Forging Technology
- •(Total Score – 15 points) unit 10 (Total Score – 30 points)
- •Forging Non-Ferrous Metals and Their Alloys
- •Unit 11
- •1) Для чого поковки із сталі підвержені тепловій обробці;
- •2) Що відбувається з поковкой під час охолодження;
- •3) Назвіть методи охолодження поковок. Cooling Forgings
Uniт 2 (Total Score – 18 points
1. Прочитайте текст і скажіть, чим відрізняється вуглеродна сталь від легированої (Score –12 points)
Classification of Steels
Steels are classified according to their manufacturing process, chemical analysis, and application.
Depending on their manufacturing process, steels are classified as Bessemer, Thomas, basic open-hearth, acid open-hearth, electric and crucible steels. Bessemer steel is smelted by blowing compressed air through molten pig-iron in a special converter-retort.
In this converter the molten metal is further heated by the heat evolved during the burning-out (oxidation) of the silicon and other elements contained in the pig-iron.
Pig-iron used for manufacturing Bessemer steel must have a low phosphorus and sulphur, content.
If, however, ordinary grades of pig-iron are used for manufacturing Bessemer steel, the latter will have sulphur and phosphorus contents of up to 0.06 and 0.08 per cent respectively, which limits its application in the manufacture of important parts.
Thomas steel, like Bessemer steel, is manufactured in converters, with the difference that in the Thomas process, the converters are lined with dolomite brick. The employment of such a lining enables high-phosphorus pig-iron to be processed in converters, the resulting steel having a lower phosphorus content than Bessemer steel.
Basic open-hearth is manufactured in open-hearth furnaces, the hearths of which are lined with magnesite (basic) brick. In this process, the furnace is charged with pig-iron and steel scrap. Basic open-hearth steel is employed for the manufacture of important parts.
Acid open-hearth steel is made in similar open-hearth furnaces as used for basic open-hearth steel in this case, however, the furnace hearths are lined with dines (acid) brick fused on with quarts sand.
The charge in this process consists of pig-iron, iron scrap and steel scrap.
The phosphorus content of the charge should not exceed 0,03 per cent, as in this process all the phosphorus is retained in the steel. When high-qualites charging materials are used high-grade steel can be obtained in acid open-hearth furnaces.
Electric steel is made in electric arc or induction furnaces; in this process the furnace hearths may be either basic or acid. Electric steel is of high quality and is employed for the manufacture of more important parts.
Crucible steel is manufactured in refractory crucibles: the charge for steel made by this process must be of particularly high quality. Crucible steel is rarely used owing to its high cost; electric steel is usually employed in its stead.
As regards chemical composition, steels are divided into carbon and alloy steels. Carbon steels contain iron and carbon with amount of constant admixtures: up to 1 per cent of manganese up to 0.5 per cent of silicon, and a maximum of 0.05 per cent each of sulphur and phosphorus.
The fundamental element which determines the mechanical properties of steel is carbon. The carbon content depends on the use to which the steel is to be put, and can very over a wide range, from the very low figure of 0.02 to 0.03 per cent in iron to 1.2 – 2.4 per cent in heat-resistant and tools steels.
Alloy steels are steel alloys containing special alloying elements such as nickel, chromium, molybdenum, tungsten, vanadium, cobalt, manganese and others; the alloying element determines the name of the steel.
Thus, for instance, if it is chromium, nickel, or both, the steel will be known as chromium, nickel, or chromium-nickel steel.
As regards application, steels are classified as: structural, tool, and special steels. Structural steels in turn are subdivided into carbon structural steels and alloy structural steels.
Structural carbon steels are employed for the manufacture of less important parts, and alloy structural steels for more important parts.
Tool steels are employed for the manufacture of various tools-cutting, measuring, dies and other tools and instruments. They are divided into two groups - carbon and alloy tool steels.
Special steels include heat-resistant refractory, stainless, acid-resistant and other steels.
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What do you know about the classification of steels?
What are the manufacturing processes of classification of steels?
Ш. Знайдіть у тексті назви виробничих процесів класифікації сталі і розкажіть, що уявляє собою кожен з них. (Score – 10 points)
(Total Score – 18 points)