MATERIALS TECHNOLOGY

Since the technology of any age is founded upon the materials of the age, the era of new materials will have a profound effect on engineering of the future.

Not only new materials, but related, and equally important, new and improved and less wasteful processes for the shaping, treating and finishing of both traditional and new materials are continuously being developed. It is important that an engineer should be familiar with them. These include casting, injection molding and rotational molding of components of ever increasing size, complexity and accuracy; manufacture of more complex components by powder metallurgy techniques; steel forming and casting processes based on new, larger and more mechanized machines, giving reduced waste and closer tolerances; the avoidance of waste in forging by the use of powder metallurgy or cast press-forms and new finishing processes for metals and plastics, just to name a few. A high proportion of these processes are aimed at the production of complex, accurate shapes with a much smaller number of operations and with far less waste than the traditional methods of metal manufacture.

Joining techniques have developed to unprecedented level of sophistication and are also providing opportunities for economies. It is necessary to mention that these newer techniques allow the manufacture of complicated parts by welding together simpler sub-units requiring little machining; such assemblies can be made from a variety of materials. The methods can also be used effectively for assembly, allowing savings to be made in both materials and machine utilization.

The brief review of new processes above has indicated that a new materials technology is rapidly emerging, providing new opportunities and challenges for imaginative product design and for more efficient manufacture.

2.Find in the text English equivalents to the following words and word combinations:

великий вплив, промисловість, обробка, формування лиття, центробіжна формовка, жорсткий припуск, чистова обробка, складність, точність, порошкова металургія, модернізація, технології з’єднання, зварка, механічна обробка, ефективне виробництво.

3.Find odd words:

treat, finish, process, provide;

cast, complicated, complex, compound;

utilize, use, make, employ.

4.Make word combinations from the following words. Translate them into Ukrainian.

5.Put verbs in brackets in right tense. Translate these sentences into Ukrainian.

1. If the technology of any age _____ upon the materials of the age, the era of new materials would have a profound effect on engineering. (to be founded)

2. If an engineer knew these materials, he _____ them for shaping, treating, casting. (to use)

3. If new materials _____, they would be used for casting, injection molding, rotational molding of components. (to be developed)

4. If an engineer knew some materials, he _____ the principle of manufacture of more complex components by powder metallurgy. (to use)

5. If an engineer had named these principles, we _____ them in our production. (to use)

6. If joining techniques _____, they would have provided opportunities for economy. (to develop)

7. If these methods had been used for assembly, they _____ savings to be made in both materials and machine utilization. (to allow)

8. If new materials technology _____, it would have provided new opportunities for more efficient manufacture. (to be emerged)

6.Answer the following questions:

1. Why are different types of materials continuously being developed?

2. What wasteful processes do you know?

3. What are the wasteful processes aimed at?

4. What do joining techniques allow?

5. What opportunities and challenges does a new materials technology provide?

Section 2

1.Read and translate the following text:

PROPERTIES OF METALS (I)

Let us see why metals have come to play so large a part in man’s activities. Wood and stone are both older in use, yet to a considerable extent they have been supplanted by the metals. The cause of the increasing use of metals is to be found in their characteristic properties, such as: strength, or ability to support weight without bending or breaking; combined with toughness, or ability to bend rather than break under a sudden blow; resistance to atmospheric destruction; and malleability, or ability to be formed into desired shapes. Malleability of a metal is also known as its ability to deform permanently under compression without rupture. It is this property which allows the hammering and rolling of metals into thin sheets.

Metals can be cast into varied and intricate shapes weighing from a few ounces to many tons. Their plasticity, or ability to deform without rupture, makes them safe to use in all types of structures, and also allows their formation into required shapes through forging and other operations.

Metals also possess the important property of being weldable. Of all the engineering materials only metals are truly weldable and repairable. Other materials used in engineering constructions, including glass, stone, and wood, usually are destroyed when the structure is no longer usable. On the other hand, an unusable bridge, ship, or boiler made of metal usually is cut into easily handled sections, put in a furnace, remelted, cast, and finally worked in the making of a new ship, bridge, or boiler.

All of this represents a remarkable combination of properties possessed by no other class of materials. Some metals also possess additional, special properties, two of which are power to conduct electric current and the ability to be magnetized. The selection of the proper metal or alloy for a given use is an important part of the practice of metallurgy. Because iron and steel are used in larger quantities than any of the other metals, it is common practice to divide metallurgical materials into ferrous, or iron-bearing, and nonferrous, or those containing no iron, or only small proportions of iron.

2.Find in the text English equivalents to the following words and word combinations:

діяльність людини, бути заміщеним металом, супротив, згинання, поломка, ковкість, атмосферне руйнування, складні форми, піч, декілька унцій, проводити електричний струм, з іншого боку, сплав, спеціальні властивості, залізомісткий.

3.Make word combinations from the following words and translate them into Ukrainian:

4.Put verbs in brackets in Passive form. Translate these sentences into Ukrainian.

1. Wood and stone already (to supplant) by the metals.

2. The cause of the increasing use of metals (to find) in their characteristic properties.

3. Many years ago malleability of a metal (to know) as its ability to deform permanently under compression without rupture.

4. The metals (to use) safe in all types of structures due to plasticity.

5. Metals can (to cast) into varied and intricate shapes.

6. Stone usually (to destroy) when the structure is no longer usable.

7. Some metals (to magnetize).

8. Unusable bridge, ship, or boiler made of metal usually (to cut) into easily handled sections, (to put) in a furnace and (to remelt).

9. Iron and steel (to use) in large quantities.

10. Metallurgical materials (to divide) into ferrous and non-ferrous.

5.Answer the following questions:

1. Why were wood and stone supplanted by metals?

2. What are the characteristic properties of metals?

3. Why is metal considered more repairable than stone and wood?

4. What property allows the rolling of metals into thin sheets?

5. What is a malleability?

6. Can wood and stone be welded?

7. Can wood and stone be used for conducting electric current?

8. How are all metals divided?

Section 3

1.Read and translate the following text:

PROPERTIES OF METALS (II)

Strength with plasticity is the most important combination of properties a metal can possess. Strength is the ability of a material to resist deformation; plasticity is the ability to take deformation without breaking. Metals possessing this combination of properties may be used in main parts of structures or machine tools.

Strength as well as ease of shaping and low cost to a considerable extent determines the fact that steel is suitable for many structural purposes. Steel is used for the structural parts of buildings, rails, and ships. For automobile parts and where greater strength and toughness are required, more expensive special steels are used. Generally, if strength alone is the main consideration, nonferrous alloys should not be used. However, where the requirement for strength is combined with resistance to rusting, aluminium bronze may be used. There are purposes for which strength is not so important as ease of machining. In making screws, for example, another kind of steel or brass may be used. Where the finished form is to be produced by casting, and great strength is not required, cast iron or cast brass may find application.

Steel may be considered the most important of all metals. It can be made soft enough for machining or for cutting and forming to the desired shape, and then by heat treatment it can be properly hardened for use as a tool.

For making airplane parts, and in other applications where strength must be combined with light weight, metals such as aluminium or magnesium or their alloys are used. Metals vary greatly in their resistance to atmospheric and chemical corrosion. A list of the elements in the order of their resistance to corrosion will begin with gold and platinum, and it ends with potassium which burns in contact with water: platinum, gold, silver, copper, tin, lead, iron, zinc, aluminium, magnesium, and potassium.

But this list may not be used in practice, as both aluminium and zinc form protective coatings in the beginning of oxidation and are not destroyed any more, while iron or steel, if unprotected, will rust through. The so-called stainless steels are used in large quantities now without protective coatings and do not rust.

Copper and aluminium are the best conductors of electric current after silver, which has practically no resistance. Copper has less resistance than aluminium for the same size wire, but aluminium, being much lighter in weight, has less resistance per unit of weight.

2.Find in the text English equivalents to the following words and word combinations:

пластичність, деформація, жорсткість, сплави кольорових металів, виготовлення гвинтів, знаходити застосування, ржавіння, лита латунь, легка вага, магній, мідь, олово, свинець, залізо, калій, захисне покриття, опір, дріт, корозія, нержавіюча сталь.

3.Give synonyms for the following words:

to supplant, various, hard, small, to desire, clean.

4.Give antonyms for the following words:

active, destroy, able, large, solid, cold, brittle, strong, cheap, dark, little.

5.Translate the following groups of words:

to act — action — active — activity — to activate — activation; to consider — consideration — considerable — considerably; able — ability — to enable; to blow — a blow — blast; to destroy — destruction — destructive; a shape — to shape; to press — to compress — compression — compressive; to vary — variation — various — variety; to bear — bearing; to unite — union — a unit; to protect — protected — unprotected; to use — usable — unusable.

6.Put the verbs in brackets in Passive form.

1. Metals, possessing the combination of some properties (to use) in main parts of structures or machine tools.

2. Steel (to use) for the structural parts of buildings, rails, ships.

3. When the requirement for strength (to combine) with resistance to rusting, aluminum bronze may (to use).

4. Steel (to consider) the most important of all metals.

5. Aluminum and zinc form protective coatings in the beginning of oxidation and not (to destroy).

6. Stainless steels (to use) in large quantities now.

7. Steel can (to make) soft enough for machining.

7. Answer the following questions:

1. What is strength?

2. What is hardness?

3. What metals possess high resistance to atmospheric destruction?

4. What ferrous metal is very hard but not strong?

5. What is toughness?

6. What is malleability?

7. What is plasticity?

8. What light weight metals do you know?

9. What is the property allowing forging and rolling metals?

Section 4

1.Read and translate the following text:

Date: 2015-01-02; view: 3026