ТОР 5 статей:
Complete the sentences. Translate them.
1) Parting sand is usually in the form of ….
2) The purpose of the riser is to compensate for ….
3) An opening on the top of the mold for pouring the metal is called ….
4) The gating system includes the pouring basin, the gate sprue, the gate and the ….
5) Vent holes are made in the sand ….
6) The gating system must be produced in the mold ….
runner; properly; the pouring basin; the shrinkage of the metal during the solidifying process; fine powder; in several places.
31. Complete the sentences using conjunction «in order to …» (для того чтобы; чтобы). Write down the sentences and translate them.
e.g. 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. Read the Text D. What is this text about? Translate it.
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.
hard – плотно, плотный
soft – слабо, слабый
readily – быстро, легко
to cause – вызывать
blowhole – раковина.