M. Ibbotson - Professional english in use engineering (794233), страница 13
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Sometimes there is more than one possible answer.The first stage in manufacturing the blades for the cutting tools is to form them into anapproximate shape by (1) a process of squeezing molten metal through a die. Beforethe blades have cooled, they are then (2) hammered while still at a high temperature- a process which not only flattens them into their final shape, but also ensures themetal becomes (3) harder as a result of the hammering action. The blades are then(4) cooled quickly in water. Finally, they are (5) bombarded with small metal balls inorder to further increase their surface hardness.Ove,r .f-o 11ou •Think of a type of steel component that needs to have specific properties.
Suggest differentways of obtaining these properties by forging or heat treating the steel.Professional English in Use Engineering47IIJ Material formats-Raw materials for processingGenerally, raw materials are materials which need to be processed before they are used- forexample, 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, intendedto 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, whichcan subsequently be melted and cast.
Very large steel ingots are called blooms. One standardsize for steel blooms is 630 mm x 400 mm x 6 m. Steel can also be supplied in smallerblocks, of various sizes, called billets.-Formats of processed materialsMaterials 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 canbe round bars (or rods) which have a circular section. They may also be square bars, witha square section, and flat bars, with a flat, rectangular section. A bar is generally made ofmetal, but a rod can be made of any material.•Sheets are flat, wide and thin - for steel, thinner than about 3 mm. Other materialssupplied in sheets include plastic, glass and wood.
However, sheets of wood are oftencalled boards. When sheets of metal (or metal sheets) are delivered in large quantities, theycan be supplied in rolls called coils.•Plates are flat pieces of metal that are wide, but thicker than sheets (for steel, thicker than3mm). Non-metals, such as glass, plastic or wood, are not usually called plates; even ifthese materials are thicker than 3 mm, they are usually called sheets.•Structural steel sections are made from rolled or extruded steel, and produced in avariety of section shapes. !-sections, with profiles in the shape of the letter 1, are commonexamples.
(See Appendix Von page 106 for types of structural section.)•Tubes are hollow, not solid. The most common types are round tubes, but square tubesand 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, along, thin, single piece of material. They are usually supplied in coils. Several wires can becombined 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 groupedtogether (called a stranded wire). An electrical cable has several conductors, separatelycovered with insulation, grouped within a second outer layer of insulation.Bectric:al c:able with solid wiresStranded wiresNote: Tubes can also be called tubing -for example, steel tubing.48Professional English in Use Engineering21.1Decide whether the sentences below are true or false, and correct the false sentences.
Look atA opposite to help you.234521.2Raw materials are often intended to be melted or mixed.Powder particles are smaller than pellets.Pellets do not reg uire further processing.A steel bloom is a type of ingot.Steel billets can be cut into smaller sized pieces called blooms.Complete the descriptions below the photos using the words in the box. You will need to usesome words more than once.
Look at B opposite to help you.cablecoilbarbloomr:~-flatplate------rodroundsheetsolid95a steel ............................ .a steel ............................ .a ............................. ·····························or a ............................ .26a ............................. of steel310a ............................. .............................a PVC ............................ .an electrical .............................117a ............................. of glassa steel ............................ .a ............................ .1284Ove-r 1-o tjouw1restrandedtubea steel ............................
.a ............................. ·····························~Think about the individual components in a device, installation or structure you know about.In what form do you think the material used for each component was supplied?Professional English in Use Engineering49l'.lJ 3D component features-30 forms of edges and jointsThe plan and sections below show the end of a stainless steel pipe and an access plate, whichare part of a production line at a chemicals manufacturing plant.The top edge of the plate is chamfered- at an angle of 45 degrees with the sides of the plate.All the other edges are square (90 degrees). Around the bottom of the plate is a rebate - aninternal corner. The top of the pipe is also rebated around the inside, so that the bottom ofthe plate can slot into the top of the pipe.In the rebate on the pipe, there is a ridge - a long, thin, raised surface.
On the plate, a grooveor channel is cut into the metal. The ridge on the pipe slots into this groove to form a tongueand-groove joint (the ridge is the tongue) . When the two are slotted together there is a cavityor void (a hollow space) between the top of the tongue and the end of the groove. This is toaccommodate (provide a space for) a rubber sealing ring.-~Ithrough holeblind hole(threaded)SE CTIONB- Bedge••- - - ----f-- - -access plate'-----===:::::::- rebate"~grooveSECTION'~ I ~~ rubber sealing ringA-A (1)tonguepipe,---------~--~---- chamferedj~fU'-r--1SECT-------.IONIA-A(2)-screw head-design 1screw head-design 230 forms of holes and fasteners50•The holes in the plate, for screws, are through holes- they go through the metal.
Theholes in the pipe wall are blind holes - they do not go all the way through. The screwswhich are intended to be screwed into these holes (by a turning action) have threads(helical grooves). The internal surfaces of the holes in the pipe walls are also threaded.•The screws are machine screws, which have a constant thickness - their thickness isthe same along their length.
Many other screws are tapered - their thickness decreasestowards the tip of the screw (the narrower end). Many screws are also pointed- thethickness of their tip reduces to zero.•Two design options are shown for the screw heads. In Design 1, the screw has a roundhead, which is raised or proud - it is at a higher level than the surface of the plate. InDesign 2, the screw has a flat head and is fully recessed - the head is within the thicknessof the plate.
The head is flush with (at the same level as) the top of the plate. To makethe screw heads flush, the top of the hole and the sides of the screw head are chamfered.Recessing screws in this way is called countersinking - the screws are countersunk.Professional English in Use Engineering22.1The extracts below are from technical conversations about machine tools . Match the pairs ofsentences and choose the correct word from the brackets in the second sentence. Look at Aand B opposite to help you.According to the drawing, we cut to a depth of 40 mm in a 60 mm thick plate.2 The edge of the die is cut off at 45 degrees.3 The tool is used as a scribe for scratching lines on the surfaces of ceramics.4 It's important to ensure the joint fits together properly.5 The surface needs to be flat.a So the inside of the (groove/tongue) must be perfectly smooth.b So the screw heads must be (raised/flush).c It's a (blind/through) hole.d That's why the end is (rounded/pointed), to make it sharp.e It's (chamfered/rebated) .22.2Complete the description of a screwdriver and screw using the words in the box.
Look at Aand B opposite to help you.accommodatechamferedconstantcountersunkflushgrooverecessedridgeroundedslotsquaretaperedthreadedtipThe end of the screwdriver is (1) ................................ ,progressively reducing in thickness towards its(2) ................................ . This allows it to fit a range ofdifferent sized screw heads.The screw has a flat head. Running across the centreof the head is a (3) ................................
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