TOPIC 9. MATERIAL FORMATS

Text 1

 

1.Обратите внимание на перевод следующих слов и словосочетаний:

raw material - сырьё;

powder - порошок;

pellet - гранула;

fibre - волокно;

steel ingot - стальная болванка;

bloom - блюм (полупродукт металлургического производства — стальная заготовка сечения, близкого к квадратному, со стороной свыше 140 мм);

billet – плашка, брусок, заготовка, болванка;

 

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RAW MATERIALS FOR PROCESSING

   Generally, raw materials are materials which need to be processed before they are used - for example, melted and cast in a mould. Common formats of raw material are:

• powder: quantities of very fine (small) particles, such as cement powder

• pellets: larger, standard-sized pieces of material, typically pea-sized to egg-sized, intended to be melted for forming in moulds - for instance, plastic pellets

• fibres: very fine, hair-like lengths, such as glass fibres.

  When steel and other metals are produced, they are made into blocks called ingots, which can subsequently be melted and cast. Very large steel ingots are called blooms. One standard size for steel blooms is 630 mm x 400 mm x 6 m. Steel can also be supplied in smaller blocks, of various sizes, called billets.

 

Text 2

 

1.Обратите внимание на перевод следующих слов и словосочетаний:

bar - брусок; болванка (металла);

rod -     прут;

sheet - лист (бумаги, стекла, металла);

board – доска;

roll -     рулон , бухта;

coil - бухта (каната, провода);

plate - плита (металла), лист;

structural steel section -    стальные профили;

tube - труба;

hollow - пустой, полый;

solid - плотный, сплошной, цельный;

pipe - труба;

wire - проволока, провод;

cable - кабель;

insulation -    изоляция;

solid wire - одножильный провод;

stranded wire - многопроволочный провод.

 

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FORMATS OF PROCESSED MATERIALS

Materials are frequently supplied ready for use in the formats described below.

• Bars are long lengths of solid metal with a relatively small cross-sectional area. These can be round bars (or rods) which have a circular section. They may also be square bars, with a square section, and flat bars, with a flat, rectangular section. A bar is generally made of metal, but a rod can be made of any material.

• Sheets are flat, wide and thin - for steel, thinner than about 3 mm. Other materials

supplied in sheets include plastic, glass and wood. However, sheets of wood are often called boards. When sheets of metal (or metal sheets) are delivered in large quantities, they can be supplied in rolls called coils.

• Plates are flat pieces of metal that are wide, but thicker than sheets (for steel, thicker than 3mm). Non-metals, such as glass, plastic or wood, are not usually called plates; even if these materials are thicker than 3 mm, they are usually called sheets.

• Structural steel sections are made from rolled or extruded steel, and produced in a

variety of section shapes. I-sections, with profiles in the shape of the letter I, are common examples.

• Tubes are hollow, not solid. The most common types are round tubes, but square tubes and rectangular tubes are also produced. Pipes are specifically for carrying liquid or gas. A pipe is therefore just one type of tube.

• Wires are thin lengths of metal with circular sections, consisting of one strand - that is, a long, thin, single piece of material. They are usually supplied in coils. Several wires can be combined to form a cable. An electrical wire is a single conductor covered with insulation. The conductor can be a single wire (called a solid wire) or several strands of wire grouped together (called a stranded wire). An electrical cable has several conductors, separately covered with insulation, grouped within a second outer layer of insulation.

 

4.Скажите, являются ли данные утверждения верными (true or false)?

 

1 Raw materials are often intended to be melted or mixed.

2 Powder particles are smaller than pellets.

3 Pellets do not require further processing.

4 A steel bloom is a type of ingot.

5 Steel billets can be cut into smaller sized pieces called blooms.

 

TOPIC 10. MACHINING

Text 1

 

1.Обратите внимание на перевод следующих слов и словосочетаний:

machining - обработка на станке (механическая);

hole - отверстие;

groove - паз;

thread - резьба;

swarf - мелкая металлическая стружка;

chips - отходы, стружка;

 

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MACHINING AND CNC

Machining is the use of machines to cut pieces of material (called workpieces) and shape them into components. The tools used in machining, to make holes, grooves, threads, etc., are called machine tools. Metal is often machined. As it is cut, waste is produced, called swarf or chips. During machining, a liquid called cutting fluid may be pumped onto the workpiece to act as a coolant, keeping the workpiece cool.

In manufacturing, machining is usually guided by computers called computer numerical control (CNC) systems. Often, design information (on shapes and sizes of components) is fed directly into CNC systems from computer aided design I computer aided manufacturing (CAD/CAM) software.

 

Text 2

 

1.Обратите внимание на перевод следующих слов и словосочетаний:

milling - фрезерование;

milling machine - фрезерный станок;

turning - вращание;

circular cross-section - круговое сечение;

sawing - пиление;

band saw - ленточная пила;

power hacksaw - ножовочная пила;

drilling - сверление;

drill - сверло, бур;

drill bit - буровое долото, сверло;

holesaw - кольцевая пила (для прорезки отверстий);

core - сердцевина;

boring - сверление;

grinding - шлифование;

grinder - шлифовальный станок.

 

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MACHINING WIH CUTTING TOOLS

Milling is cutting done by a milling machine, often using toothed cutting discs (wheels with teeth that have sharp edges). When a workpiece is milled, it is held in a fixed position on the machine, and is shaped by cutting tools which rotate (spin) while being moved over the surface of the workpiece.

Turning is a technique for cutting components that have a circular cross-section. The workpiece is turned by a machine called a lathe, which rotates the workpiece. A fixed machine tool is then moved against the rotating workpiece to cut material from it.

Sawing is cutting using a blade (a thin, sharp piece of metal), which usually has teeth, to remove a thickness of material slightly wider than the blade. The gap left by the blade, along the line of the cut, is called a kerf. Machines that use toothed blades include circular saws, which have rotating circular blades, band saws, and power hacksaws. A hacksaw has a blade with very small teeth, for cutting metal. Saws may also use abrasive wheels - that is, thin, circular cutting wheels with rough, hard surfaces - often made of industrial diamond.

Drilling is a technique for cutting circular holes. A machine called a drill is fitted with a tool called a drill bit (or bit). The bit rotates and drills into the material. Holes with large diameters can be cut using holesaws- hollow cylinders with teeth, which saw circular cuts and remove a core (a solid cylinder) of material. When used to drill into concrete, this technique is also called core drilling, or diamond drilling, as the holesaws have industrial diamond edges. Usually, drilling refers to making new holes. In machining, enlarging a hole (making it wider) is called boring.

Grinding is removing material across a surface area, using abrasive wheels. The machines used to grind materials with abrasive wheels are called grinders.

 

4.Соедините две части предложений:

1 A drill bit is an example of

2 Material being machined is called

3 The waste metal produced during machining is called

4 Metal gets hot during cutting, so cutting fluid can be used as

5 A computer that guides a machining process is called

6 Drawings can be produced and transferred to the machining process using

a CAD/CAM software.

b a CNC system.

c a machine tool.

d a workpiece.

e swarf or chips.

f a coolant.

 

5.Используйте эти слова, чтобы дополнить предложения: drill, grind, mill, turn, saw

1 Lathes are designed to ................................ workpieces.

2 Different bits are designed to ................................ into different types of material.

3 When you ................................ a workpiece, the cutting blade removes a thickness of material to form a kerf.

4 Abrasive wheels ................................ material.

5 On some machines, toothed cutting wheels can be used to ................................ any part of a workpiece, in order to form its final shape.

 

Text 3

 

1.Обратите внимание на перевод следующих слов и словосочетаний:

shear force - срезывающая сила;

guillotine - гильотинные ножницы;

punch - пресс;

blank - болванка;

blanking - штамповка (технический способ обработки металла давлением)

 

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GUILLOTINING AND PUNCHING

Thin materials can be cut by applying pressure in order to shear them - that is, cut them with a scissoring force (in engineering, called a shear force). Sheets of metal can be sheared using a machine called a guillotine, which has a long blade. Usually, sheets are guillotined when long, straight cuts are required.

Small shapes, such as circles, can be sheared from sheets using a machine called a punch, which pushes a die (a shaped tool) through the sheet. The shaped piece of metal that is punched from the sheet is called a blank. If the blank is the finished product, this process is called blanking. If the sheet itself, with holes made in it, is the finished product, the process is called piercing.

 

Text 4

 

1.Обратите внимание на перевод следующих слов и словосочетаний:

flame-cutting - газопламенная резка;

torch - сварочная горелка;

electrical discharge machining - электроискровая обработка (металлов);

electric arc - электрическая дуга;

plasma torch - плазменная горелка;

 

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HIGH-TEMPERATURE METAL CUTTING TECHNIQUES

  Flame-cutting generally uses oxygen (02) and acetylene (C2H2). The two gases are blown through a torch - basically a tube - as a mixture called oxyacetylene. The acetylene burns in the oxygen to produce a flame hot enough to melt steel.

 Electrical discharge machining (EDM) - also called spark erosion - involves passing a tight length of wire through a workpiece, similar to the way thin wire is used to cut cheese. However, the wire does not actually touch the workpiece. Instead, a high-voltage current produces an electric arc, which 'jumps' across a small gap between the wire and the workpiece. As the current arcs, it generates heat, which melts the metal ahead of the wire.

 Plasma cutting uses a plasma torch to blow out gas at high pressure. The gas argon (Ar) is often used. At the same time a high-voltage current is passed through the plasma torch, and arcs between the torch and the workpiece. This ionizes some of the atoms in the gas, changing it to plasma. As the plasma is heated by the arc, it reaches an extremely high temperature - much hotter than would be possible for a gas that had not been ionized.

Text 5

 

1.Обратите внимание на перевод следующих слов и словосочетаний:

laser beam - лазерный луч;

laser cutting - лазерная резка;

waterjet cutting - резание с помощью водяной струи.

 

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LASER CUTTING AND UHP WATERJETS

Laser beams (concentrated light) can cut materials accurately, in small quantities, by melting them. Laser cutting is especially suitable for plastics.

Ultra-high-pressure (UHP) waterjets- jets of water fired at extremely high pressure - can cut almost any material, including metal. An advantage of UHP waterjet cutting is that the edge quality of workpieces is high- that is, the cut edges are smooth. This means that no secondary operations- further processes to smooth rough edges- are required. Also, because UHP waterjets are cold, they do not leave a heat-affected zone (HAZ) on the workpiece that is, an area near the cut edge whose properties have been changed by heat.

 

4.Ответьте на вопросы:

1 In machining, what does EDM stand for?

2 What alternative term can be used instead of EDM?

3 What type of tool is used in both flame-cutting and plasma cutting?

4 What source of heat is used in both EDM and plasma cutting?

5 What needs to happen to a gas in order to turn it into plasma?

6 What term refers to concentrated light that can be hot enough to cut material?

7 What term refers to an area of material that has been changed by high temperature?