31. Соедините две части предложения союзом цели «in order to …» – для того чтобы; чтобы. Запишите полученные предложения. Переведите их

f.e. Ladles of different sizes are used in the foundry, … to pour the molten metal into molds.

Ladles of different sizes are used in the foundry in order to pour the molten metal into molds.

1) Clay is mixed with silica sand, … to make the molding mixture strong.

2) Facing material is applied for the mold cavity, … to prevent the sand from sticking to the hot metal.

3) The molding sand must be refractory, … to withstand high temperature of the poured metal.

4) Gating system is produced in the sand mold, … to supply the molten metal to the mold cavity.

32. Прочтите текст d, переведите его и скажите о каком процессе (формовке, заливке, трамбовке) идет речь Text d

Ramming of the sand is necessary in order to make the sand retain its position (заставлять землю удерживать свое положение) in the mold. The sand is rammed around the pattern. Long practice is necessary for proper ramming. The proper ramming depends upon the molding sand used, the metal poured, and other factors. Ramming too hard will close up openings (vents) in the sand, so that steam and gases produced during pouring process cannot readily escape. This may cause blowholes in the casting. Too soft ramming will not give sufficient strength to the sand and mold surface. This may alloy the flow of molten metal to make the casting larger than the pattern or may cause other casting defects.

The joint and the bottom parts of the mold must be rammed harder than the upper portions.

Unknown words to the text D:

hard – плотно, плотный

soft – слабо, слабый

readily – быстро, легко

to cause – вызывать

blowhole – раковина.

33. Используя текст D, ответьте по-английски на следующие вопросы

1) Where is the sand rammed?

2) Is long practice an important factor for producing proper ramming?

3) What other factors does the proper ramming depend upon?

4) What defects may too hard ramming and too soft ramming cause?

5) What parts of the mold must be rammed harder?

34. Распределите пункты плана в последовательности, соответствующей содержанию текста D

a) Purpose of ramming.

b) Ramming of different parts of the mold.

c) Defects in ramming.

d) Requirements to ramming.

35. Озаглавьте по-английски текст D.

Part IV types of molds

1. Прочтите, что обозначают следующие слова. Запомните их

dry – сухой

to dry – сушить

dry – sand mold – сухая форма; форма из сухой земли

f.e. Dry sand and dry bonds are often used to produce sand molds.

f.e. Dry – sand molds are usually used when castings of high quality are necessary.

f.e. Sand molds are dried by different methods.

green (damp) – sand – сырая земля

damp molding sand – сырая земля

green-sand mold – сырая форма; форма из сырой земли

damp-sand mold – сырая форма; форма из сырой земли

f.e. Damp sand is used for damp-sand molds.

f.e. Green – sand molds are widely used because of their low cost and simplicity of operation.

skin – dried mold – форма, просушенная с поверхности (соприкасающаяся с заливаемым металлом)

f.e. Skin-dried molds are used for certain types of sand castings.

f.e. Dry – sand mold, damp – sand mold, air – dried mold, skin – dried mold are types of sand molds for producing sand castings.

permeability – газопроницаемость

f.e. During ramming the permeability of green sand becomes lower.

to withdraw – удалять

f.e. The pattern is withdrawn when the sand has been properly rammed.

to cause – вызывать; производить; влиять (быть причиной)

f.e. The contact of hot metal with green – sand mold causes the forming of steam in the mold.

crack – трещина; раковина; закалочная трещина

cooling crack – трещина, возникающая при охлаждении

hot crack – трещина, возникающая при нагреве

weak – слабый

f.e. Too weak ramming causes defects in the casting.

complicated – сложный

f.e. When the casting must be large, a more complicated mold is required.

solid – твердый

solid shrinkage – усадка металла в твердом состоянии

f.e. Solid shrinkage takes place in the hot metal when it cools from solidifying temperature of the air.

quantity – сложный

f.e. For large quantity production mechanical means are used for making molds.

to assemble – собирать, монтировать

f.e. Too large molds are made and assembled on the floor.

f.e. The preparation and assembling of green sand and dry – sand molds is very much the same.

commonly – обычно.