CASTING AS A METHOD OF BLANK PRODUCTION

1. The main advantages of casting as a method of blank production lie in:

A. The possibility of casting production from the majority of construction alloys and, in particular, from those which are not suitable for forming (for instance, various sorts of cast-iron).

B. The possibility of producing blanks of a very complicated shape, especially blanks with a complicated shape of inner cavities.

C. The possibility of producing blanks weighting from a few grams up to several hundreds of tons.

2. Various technological processes are used in the foundry practice. The differences between them lie mainly in the sort of materials used for the foundry moulds, the method of the mould manufacture and conditions in which liquid metal is poured into the moulds. The basic moulding process is sand-mold casting which accounts for 80% of the total output of cast products.

3. Castings are made from irons and steels and from non-ferrous alloys such as copper, aluminium, magnesium, zinc and other types. The castings from metals and alloys find wide use as parts of machines and instruments turned out by the machine-building and instrument-making industries.

4. However, in spite of great advantages, the method of casting is not universal as it has its own disadvantages, for example, difficulty and, sometimes, impossibility to produce castings with the desired accuracy of dimensions and surface finish.

5. That is why special casting processes find an ever increasing application. These are permanent-mold casting, die casting, investment casting, shell casting, centrifugal casting and other precision processes which produce cast components of increased dimensional accuracy and low surface roughness with minimum finish allowances.

Task 1. Find in the text English equivalents to the following words and word combinations:

виробництво заготівок, різні сорти, складна форма, придатний для штамповки, внутрішня порожнина, застосування, точність, піщана форма, приладобудівний, лиття в постійні форми, лиття в кокіль, точне лиття по виплавленим моделям, центробіжне лиття, обробка поверхні, мінімальні припуски на обробку, шорсткість поверхні.

Task 2. Find in the text synonyms to the following words:

to produce, to apply, to have got

Task 3. Match the words with their translations:

blank	порожнина
finish	ливарна форма
cavity	шорсткість
mould	кокіль
shell	припуски
surface	заготівка
die	поверхня
roughness	точність
accuracy	обробка
allowances	оболонка

Task 4. Combine the words and translate the word combinations into Ukrainian:

construction	cavities
complicated	industry
inner	casting
foundry	alloys
die	accuracy
total	practice
instrument-making	finish
surface	roughness
dimensional	output
surface	shape

Task 5. Give Ukrainian equivalents to the following words and word combinations:

blank production, construction alloys, cast-iron, very complicated shape, inner cavities, to weight, foundry practice, mould, liquid metal, to pour, sand-mold casting, total output, castings, non-ferrous alloys, to turn out, machine-building and instrument-making industries, desired accuracy of dimensions, to find application, permanent-mold casting, die casting, investment casting, shell casting, centrifugal casting.

Task 6. Answer the following questions:

1. Where do the advantages of casting as a method of blank production lie?

2. Where do the differences between various technological foundry processes lie?

3. What is the basic moulding process?

4. What are castings made from?

5. Where do the castings from metals and alloys find wide use?

6. What disadvantages has the method of casting?

7. What special casting processes do you know?