Alloy steels

1. When one or more metals are added to plain carbon steels, they steel acquire certain new characteristics. These steels are called “alloy steels”. Some elements are used because they make the steel stronger, tougher or more corrosion-resistant. Among such elements are manganese, nickel and silicon. Other elements are used because they combine with carbon to form carbides which make the steel harder and stronger. Among them are chromium and vanadium. The third group elements such as silicon, manganese and titanium are used in steelmaking because they limit the amount of harmful impurities which cannot be wholly removed from steel.

2. Some elements produce a great number of effects in steel but commonly more than one alloying element is necessary to produce all desired effects in a given steel. High-speed steels, which are extremely important in machine-tools, contain chromium and tungsten plus smaller amounts of vanadium, molybdenum and other metals. These steels show high durability.

3. High-alloy steels containing more than 8% alloying elements are prized for their unusual properties. Typical of these are stainless steels containing from 16 to 26% chromium and up to 35% nickel. They are used when corrosion and oxidation resistance is required, as in jet-engine parts, chemical equipment, cutting tools and cooking utensils.

4. The beneficial effects of alloying elements become especially apparent when the steel has been subjected to heat treatment. Heating in the presence of carbon or nitrogen-rich materials called case-hardening is used to form a hard surface on steel. In order to harden the steel through its cross-section, it is alloyed with manganese, nickel, chromium, silicon and molybdenum. All these elements lower the critical cooling rate and permit the steel to harden to greater depths.

5. As a matter of fact, we have a bewilderingly great variety of alloy steels in use and more are constantly being developed. The selection of an alloy steel for specific use involves a careful consideration of many factors. Not only must strength and toughness requirements be studied but also the temperature range at which specific properties are desired.

Notes

high-speed steel – быстрорежущая сталь

Grammar and Vocabulary Questionnaire

1. Is to (paragraph 1) in the phrase to plain carbon steels a preposition or the particle of the infinitive?

2. Is the infinitive to form (paragraph 1) an infinitive or an infinitive of purpose?

3. Give a synonym for a great number of (paragraph 2).

4. What is the meaning of given in the phrase in a given steel (paragraph 2)?

5. What does show mean in paragraph 2?

6. Compare alloying in paragraph 2 with alloying in paragraph 3. What parts of speech are these?

7. These in paragraph 3 is a substitute. What noun does it substitute? Translate the whole phrase Typical of these … (paragraph 3).

8. Find as in paragraph 3. Does it mean there так как, когда or как in Russian?

9. What part of speech is apparent in the first sentence of paragraph 4?

10. Is called (paragraph 4, sentence 2) Past Simple or Past Participle of the verb?

11. Which noun does it in paragraph 4 refer to?

12. In the last sentence of paragraph 4 there are two to. Which is the infinitive and which is a preposition?

13. Translate as a matter of fact at the beginning of paragraph 5.

14. Explain the usage of the Present Progressive Passive Voice (are constantly being developed ) in the first sentence of paragraph 5.

4.12. Study Table 3 and complete the text below using the words from the list.

Table 3

Composition, Ductility and Durability of Silicon, Manganese, Nickel and Tungsten Steels

STEEL	COMPOSITION		DUCTILITY	DURABILITY
Silicon steel	silicon carbon iron	2% 0.1% 97.9%	not very good	quite good
Manganese steel	manganese carbon iron	12% 1% 87%	good	poor
Nickel steel	nickel carbon iron	3% 0.3% 96.7%	quite good	not very good
Tungsten steel	tungsten chromium carbon iron	14% 4% 0.7% 97.9%	poor	good

contain, elements, four, low, more, least, chromium, ductility, best, durability, most, properties

This table shows the composition of (1) …… alloys. They all (2) …… iron and carbon, and each of them contains one or two other (3) …… . The composition determines the (4) …… of the alloys. The table gives ductility and (5) …… for each alloy. For example, manganese steel contains (6) …… carbon than the other three alloys. It is also the (7) …… ductile of them. Silicon steel has the (8) …… carbon content. Its (9) …… is rather (10) ……, but this steel is quite durable. Tungsten steel has 14% tungsten, 4% (11) …… and 0.7% carbon. Its ductility is poor, but the steel has the (12) …… durability.

13. Read the text, then using key words of each paragraph write the paragraphs summaries (one sentence for each). The summaries for the first two paragraphs are done for you:

1. The development of shipbuilding is actually connected with hull steels whose properties should meet a number of requirements.

2. Certain kinds of welded steels are used in the welded hulls of ships.

Having written the summaries, render the text. Translate the text.