Metal Mechanics

Student workbook

2

ii Metal Mechanics

Contents

Unit 1 Page 1Unit 2 2Unit 3 3Unit 4 4Unit 5 5Unit 6 6Unit 7 7Unit 8 8Unit 9 9Unit 10 10Unit 11 11Unit 12 12Unit 13 13Unit 14 14Unit 15 15Unit 16 16Unit 17 17Unit 18 18Answer Key 19

1Metal Mechanics

1 Complete the text with the words listed below.

power electrode power source arc base material

The electricity flows from the 1 through the 2 and across the 3 , through the 4 to the work lead and back to the 5 source.

2 Match the protective equipment (1–5) with the words listed below.

mitten face shield goggles hand shield gauntlet

1 2 3 4 5

3 Complete the sentences about health and safety with the words listed below.

contact goggles cables helmet

1 Always wear an appropriate welding , and clothing that covers arms and legs.2 Wear when chipping slag or wire-brushing welds.3 Keep all electrical in good condition.4 Make sure cannot be made with hot items.

4 Look at the table to find a metal for each of the properties listed below. More than one answer is possible.

1 ductile 2 malleable 3 corrosion resistant 4 good conductor

Metals Properties UsesAluminium Light, soft, ductile, highly conductive,

corrosion-resistant.Aircraft, engine components, foil, cooking utensils

Copper Very malleable, tough and ductile, highly conductive, corrosion-resistant.

Electric wiring, PCBs, tubing

Brass (65% Copper, 35% Zinc)

Very corrosion-resistant. Casts well, easily machined. Can be work hardened. Good conductor.

Valves, taps, castings, ship fitting, electrical contacts

Mild Steel (Iron with 0.15% to 0.3% Carbon)

High strength, ductile, tough, fairly malleable. Cannot be hardened and tempered. Low cost. Poor corrosion resistance.

General purpose

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5 1

4

3 2

1 Match the beginnings to the words (1–8) with the endings(a–h) to form nouns.A B1 compress- a -ee2 corro- b -ian3 equip- c -ics4 fric- d -sion5 logist- e -ment6 supervis- f -or7 technic- g -or8 train- h -tion

2 Put the words in the correct order to make questions.1 sorry I’m what but did say you ? 2 me can excuse repeat me you the for number ? 3 you could please spell that ?

3 Find eight words relating to metals. The words read from left to right (→) and top to bottom (↓).

welding corrosion rusting steel iron tensile ductile metal

4 Use the safety items listed below to label the diagram.

eye safety shield flame-proof skull cap fire-resistant gauntlet gloveshand-held helmet with filter lens safety shoesclean fire-resistant clothing

1 2 3 4 5 6

2 Metal Mechanics

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c t w z s g m r b ij m e t a l i s y cr a l s w c x d r ou q d m i c q u g rs x i r o n b c s rt e n s i l e t t oi o g a j y m i w sn i b g z c r l x ig t a w j s q e m os c s t e e l z j n

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1 Match to the processes listed below to the descriptions (1–6).

cutting soldering brazing leading welding tinning

1 Bonding by melting a soft metal to the surface of pieces to be joined. Low temperature.

2 A soldering process, where the surface of a metal is coated with solder. 3 A form of soldering, solder is used to fill in the surface of metal. 4 Similar to soldering, but uses a higher temperature to fuse the filler metal to

the work pieces. 5 Joining two similar work pieces by melting them together, usually with an additional

filler rod of some sort to take up space. Materials must be similar. 6 Work is heated to melting point and beyond, and “cut” by oxidizing metal.

2 Complete the text about fume with the words listed below.

vaporizes particulate gases oxides metal fume

Welding 1 metals, and anything which is resting on the surface. This gives rise to 2 , which is condensed fine 3 material. The fume is mostly 4

of the metals, including any alloying elements, but it also contains 5 produced in the arc,

such as ozone or oxides of nitrogen, and decomposition products from any paint or coating which was

on the 6 surface.

3 Label the Arc Welding diagram with the terms listed below.

nozzle filler rod gas shielding arc weld pool

1 2 3 4 5

4 Look at the list and mark each one as an advantage (A) or disadvantage (D) of MIG welding.

1 The ability to join a wide range of metals and thicknesses. 2 A good weld bead. 3 MIG welding can only be used on thin to medium thick metals. 4 Produces a somewhat sloppier and less controlled weld as compared

to TIG (Tungsten Inert Gas Welding). 5 All-position welding capability. 6 Easy to learn.

3Metal Mechanics

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1 Label the typical MIG torch diagram with the terms listed below.

trigger torch body gas supply tube armoured torch cable nozzletorch liner guiding filler wire contact tip with nozzle insulated neck

1 5 2 6 3 7 4 8

2 Complete the text about bonding processes with the words listed below.

join welding resistance heat binding processes

Welding and soldering 1 are used to permanently 2 two or more metal pieces

together. In 3 part of the base material is melted. Heating sources can be gas, electric arcs or

laser beams. For some of the processes an electric arc provides the 4 . In other cases it comes

from the electric 5 between two surfaces. Soldering processes utilize another more low

melting metal as a 6 agent. This means that the base material is not melted. The heating

source is typically gas.

3 Find the six words relating to metal bonding. The words read from left to right (→) and top to bottom (↓).

soldering brazing leading welding tinning cutting

4 Read the text and mark the statements as true (T) or false (F).Die casting is a versatile process for producing engineered metal parts by forcing molten metal under high pressure into reusable steel moulds. These moulds, called dies, can be designed to produce complex shapes with a high degree of accuracy and repeatability. Parts can be sharply defined, with smooth or textured surfaces, and are suitable for a wide variety of attractive and serviceable finishes.

1 Die casting is versatile. 2 Die casting forces molten metal under low pressure. 3 Moulds, or dies, cannot be formed into complex shapes. 4 Die cast parts cannot have a textured surface. 5 Die casting is suitable for a variety of finishes.

4 Metal Mechanics

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f s a d b y o h t zo o s m l h v e i ag l f w e l d i n gv d y s a e a t n gh e d f d h k y i ob r a z i n g h n tk i a b n m p f g bd n h y g o e q k sz g v m b a f g d yd o c u t t i n g h

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1 Study the diagram showing how the properties of carbon vary with the percentage of carbon in carbon steels and answer the questions.

1 What percentage of carbon gives the greatest tensile strength? 2 What happens to ductility between 0.08% and 0.87% carbon? 3 How does increased carbon affect hardness? 4 What is the effect on tensile strength of increasing carbon beyond 0.84%? 5 What happens to ductility after 0.87% carbon?

2 Match the words (1–8) with the definitions (a–h).1 compressor a someone who is learning how to do something2 corrosion b the things you need to do a job3 equipment c a machine for squeezing gas into a smaller volume4 friction d the person who checks other people’s work5 logistics e the force of two things rubbing together6 supervisor f someone who has skills in a technical area7 technician g the science of organizing the flow of supplies and people8 trainee h the damage caused by oxidization

3 What are the adjectives from these nouns? Complete the table.

Noun Adjective1 width 2 height 3 length 4 depth 5 weight

4 Match each function with a picture.1 welding 2 designing 3 grinding

5Metal Mechanics

5

a b c

Properties of carbon steels

Tensile strength

Hardness

Ductility

0.08% Carbon

0.15 0.35 0.55 0.85 1.05 1.20

1 Read the statements and mark each as a hazard (H) or risk (R).1 Using noisy equipment without ear protectors. 2 Working without a harness. 3 Damaging eyesight. 4 Falling. 5 Welding without goggles. 6 Damaging hearing.

2 Match the words (1–5) with their opposites (a–e).1 organized a dirty2 clean b disorganized3 clear (instructions) c cluttered4 clear (workbench) d unsafe5 safe e unclear

3 Match the phrasal verbs listed below with the definitions.

chase up carry out catch up get on with fall behind hold up

1 lose time on a schedule 2 perform a task 3 cause a delay 4 contact somebody in order to remind them to do something 5 spend extra time doing something because you haven’t done it earlier 6 make progress

4 Match each function with a picture.1 cutting 2 turning and shaping 3 drilling

6 Metal Mechanics

6

a b c

1 Rearrange the letters to make names of the portable power tools.

1 redgirn 2 lilrd 3 was

2 Make Present Perfect sentences and questions.1 you finish welding? 2 we do the grinding 3 you and Ahmed paint it? 4 we not paint it 5 they build the base? 6 they not finish the base

3 Read the note. Answer the questions.1 What’s the problem? 2 What has Roger asked Simon to do? 3 How long will the job take?

4 Match the functions below with a power tool or tools in the workshop picture.

welding cutting turning and shaping grinding drilling designing

1 oxyacetylene equipment 2 table saw 3 lathe 4 bench grinder 5 drill press 6 CNC bench 7 welding and cutting bench 8 MIG welding equipment

7Metal Mechanics

7

Simon,

The discharge hose in the bulk tanker loading area, bay 4 is leaking. Could you check it please? Take a spare valve with you. Go over there at 8.00 tomorrow morning. You should finish by 11.00. I’ve already done the paperwork (risk assessment, permit to work).

Thanks

Roger

Oil and Gas SB1OEfCOG1S078bMac/eps/Illustrator Col s/sText: N/AOxford University PressStudio: Peters & Zabransky

Metal storage racksDrill press

Bench grinder

CNC bench

Welding / cutting bench

Lathe

Compressor

Oxyacetylene welding equipment

MIG welding equipment

Table saw

12 Oil and Gas SB1 Unit 11 page 78.indd 78 07/11/2011 09:48

1 Complete the table.

307 three hundred and seven490 ab five thousand6,344 cd ten thousand13,450 ef three hundred thousand465,000 gh seven million75,000,000 i

2 Put the words in the correct order to make questions.1 come can I in ? 2 me you can pass hammer that ? 3 this you me help carry can pipe ? 4 hard take my off I can hat ?

3 Match the words (1–5) with the definitions (a–e).1 a safety procedure a harm done to a person’s body2 a risk assessment b a way of doing things to prevent accidents3 a technique c a report about possible dangers4 an injury d a particular way of doing something, especially one in which you 5 an incident have to learn special skills e something that happens; an event: a fire, e.g. a collision, an accident

4 Label the oxyacetylene welding equipment diagram with the words listed below.

welding torch bottle cart oxygen cylinder acetylene cylinder pressure regulator

1 2 3 4 5

8 Metal Mechanics

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5

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4

1 Write these abbreviations next to the correct words.

cm g kg km m mm t

1 grams 2 kilos 3 tonnes 4 millimetres 5 centimetres 6 metres 7 kilometres

2 Choose the correct word to complete each sentence.1 This old machine isn’t safe / safety. 2 He’s an Italy / Italian engineer. 3 Can I use your calculate / calculator please? 4 There are hazards / hazardous in my job. 5 This company is a good employ / employer.

3 Match each precaution (1–6) with a hazard (a–f).1 weld dry a gas cylinders2 always move it safely b arc sprays3 cover up skin and eyes c arc rays4 no pockets d smoke5 know the material you’re welding e electric shock6 keep the work area clean and tidy f trips and falls

4 Look at the picture. Match the parts (1–5) with the names (a–e).a gas cylinder b valve c regulator d cylinder cap e cart

9Metal Mechanics

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1 Complete the sentences with much or many.1 There isn’t ethanol in the tank.2 How gas cylinders are there?3 Is there smoke in the workshop?4 Do you get shocks when you use the arc welder?5 I don’t have information about the new project.6 How welders work on your crew?

2 Match the words below to the labels on the picture.a smoke b arc rays c welding helmet d arc e gloves f sparks

3 Match each sign with a warning.1 Don’t drop the cylinder. 2 Be careful. Don’t trip and fall. 3 Secure the gas cylinder. 4 This could explode. 5 Use the ventilation fan.

4 Choose the correct words to complete each sentence.1 We switch off equipment / an equipment. 2 There are six main hazards / hazard for welders. 3 Gas cylinder / cylinders can explode. 4 Never look at spark / the spark. 5 Hot sparks can burn clothes / a clothes and start fires. 6 Smoke / A smoke from welding can be dangerous. 7 We always know material / the material we’re welding. 8 Cover skin / a skin and eyes.

10 Metal Mechanics

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a b

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d e

1 Match the words (1–6) with the definitions (a–f).1 slag a restricted area, difficult to work in2 weld b pool of molten metal3 overhead c vitreous bi-product of welding4 confined d same shape as the tip of a pencil5 pointed e connect two alloys or metals6 puddle f welding position with arms raised

2 Complete the sentences by choosing the correct option.1 Let’s what is blocking the valve. a to find out b finding out c find out

2 We have to shut the operation immediately. a up b down c out

3 How are you planning the service? a do b doing c to do

4 This unit is wearing - it’s time to replace it. a off b on c out

3 Label the diagram with the words listed below.

torch shielding gas coolant out gas valve regulator remote control coolant system adapter block power source clamp

1 2 3 4 5 6 7 8 9

10

4 Complete the sentences using some of the words listed above.1 The amount of gas is controlled by the .2 protects the weld from contaminants.3 allows the user to switch on and off at a distance.4 The is used to keep work stable.5 The consists of tungsten, a collet and a nozzle.6 The can be a generator or electric socket.

11Metal Mechanics

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3

1 Complete the instructions using the words listed below.

torch tungsten foot pedal plug AC regulator clamp connect

A: … OK Pedro. This is your first time with this equipment. What are we going to do?B: Shall we 1 the torch?A: That’s right – good. Where do we 2 it in?B: Into the front of the machine. Here. We should also connect the gas hose and 3 .A: Good. Two more things to connect first. First the 4 so you can control the equipment….B: … and finally the 5 . Shall I attach here to the work table?A: That’s fine. Now we must check current. What do we need for aluminium?B: 6 .A: Excellent. Now check the tungsten. That looks good. Well pointed. Let’s assemble the 7 .

Put the 8 in the collet here. That’s fine.B: Are we ready?A: Let’s connect power and start.

2 Match the verbs (1–6) with the definitions (a–f).1 adjust a make sure something is correct or safe2 check b fill to the correct level3 fit c change something slightly because it is in the wrong position4 inspect d try something to see how well it works5 test e put something in the correct place6 top up f look at something very closely or in detail

3 Find eight words relating to TIG welding. The words read from left to right (→) and top to bottom (↓).

alloy torch tungsten slag gas pipe regulator power

4 Complete the table.

Comparative Superlative1 long longer the 2 heavy the heaviest3 dangerous more/ dangerous the / least dangerous4 good the best5 bad the

12 Metal Mechanics

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r a o u a i t v o rg l t o r p i p e es l a g p x j i h gh o i a r u t g l uq y t k o d n i t la j v t o r c h h ap o w e r i p g u ti x r i g q t d a ou t v a a o u n r rt u n g s t e n o a

1 Read the text and answer the questions.

What is corrosion? Corrosion is a general term which refers to the undesired oxidation of metals to oxides and other compounds. When the metal is iron, the corrosion process is called rusting. While iron is structurally strong, the iron oxides formed as the products of rusting are not. Other metals such as copper and silver become tarnished from surface oxidation of the metal. Billions of dollars must be spent annually to replace materials that have corroded. The greatest damage is from the rusting of iron and steel. It has been estimated that 25% of the annual steel production in the USA goes towards the repair and replacement of metals lost by corrosion.

1 What does the term corrosion refer to?

2 When the metal is iron, what is the corrosion process called? 3 Provide two examples of metals that become tarnished. 4 What percentage of the annual US steel production goes towards the repair and replacement of

corroded metals?

2 Read the text and answer the questions.

Gas metal arc welding Gas metal arc welding (GMAW), sometimes referred to by its subtypes metal inert gas (MIG) welding or metal active gas (MAG) welding, is a semi-automatic or automatic arc welding process in which a continuous and consumable wire electrode and a shielding gas are fed through a welding gun. A constant voltage, direct current power source is most commonly used with GMAW, but constant current systems, as well as alternating current, can be used. There are four primary methods of metal transfer in GMAW, called globular, short-circuiting, spray, and pulsed-spray, each of which has distinct properties and corresponding advantages and limitations.Originally developed for welding aluminium and other non-ferrous materials in the 1940s, GMAW was soon applied to steels because it allowed for lower welding time compared to other welding processes. The cost of inert gas limited its use in steels until several years later, when the use of semi-inert gases such as carbon dioxide became common. Further developments during the 1950s and 1960s gave the process more versatility and as a result, it became a highly used industrial process.

1 How is gas metal arc welding sometimes referred to? 2 What power source is commonly used? 3 What are the four primary methods of metal transfer in this process? 4 Why was this process developed? 5 Why was GMAW applied to steels?

13Metal Mechanics

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2058 mm

550 mm

2800 mm

655 mm

1 Complete the text about shielding gases with the words listed below.

welding gases oxygen defects problem atmospheric

Shielding 1 are necessary for gas metal arc welding to protect the 2 area from 3 gases such as nitrogen and 4, which can cause fusion 5, porosity, and weld metal embrittlement if they come in contact with the electrode, the arc, or the welding metal. This 6 is common to all arc welding processes.

2 Look at the picture. Write the measurements.1 length = 2 outside diameter = 3 pipe wall thickness = 4 outside circumference = 5 inside diameter (bore) = 6 inside radius =

3 Write sentences using the Past Continuous and the Past Simple.1 (learn) to weld when I (burn my hand).2 When I (fall), I (climb) a ladder.3 They (weld) when the fire (start).4 (you use) the computer when the power (go off)?5 He (not use) the safety guard when he (cut) his finger.6 When we (eat) lunch, the oxygen bottle (explode).

4 Read the text and answer the questions.

Fabrication Fabrication as an industrial term refers to building metal structures by cutting, bending, and assembling. The cutting part of fabrication is via sawing, shearing, or chiseling (all with manual and powered variants); torching with handheld torches (such as oxy-fuel torches or plasma torches); and via CNC cutters (using a laser, torch, or water jet). The bending is via hammering (manual or powered) or via press brakes and similar tools. The assembling (joining of the pieces) is via welding, binding with adhesives, riveting, threaded fasteners, or even yet more bending in the form of a crimped seam. Structural steel and sheet metal are the usual starting materials for fabrication, along with the welding wire, flux, and fasteners that will join the cut pieces.

1 What does fabrication mean? 2 Name three methods of cutting. 3 What is hammering used for? 4 What are the usual starting materials for fabrication?

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1 Label the arc welding equipment diagram with the words listed below.

ground clamp electrode lead arc welding machine electrode holder electrodework lead welding curtain

1 2 3 4 5 6 7

2 Read the sentences (1–3) and underline the unnecessary articles.

1 She has got an experience as a TIG welder.

2 Stop! There is a smell of the gas.

3 I don’t know how to use the equipment you sent. I need a more information.

3 Correct the spellings of these words.1 metel 2 corroshen 3 aciddent 4 sparc 5 wellding

4 Read the text and answer the questions.

TIG welding TIG stands for Tungsten Inert Gas and is a form of welding developed in the 1940s to join aluminium and magnesium. In this process, the arc is formed between a pointed tungsten electrode and the work piece in an inert atmosphere of argon or helium. It needs a constant current power source; AC for aluminium and DC for steel. The heat input is usually controlled by the operator using a remote control foot pedal. It is ideal for precision and high quality welding because there is no slag to block the operator’s view of the weld puddle. It can be used in all positions, vertical, horizontal, flat and overhead and is also useful in confined spaces. It is used in many manufacturing processes including door handles, bike frames and lawnmowers and for pipe welding boilers or chemical plans.

1 What gases are normally used in TIG welding? 2 Why was it developed?

15Metal Mechanics

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1 Read the text and answer the questions.

Tool and die makers Tool and die makers are among the most highly skilled workers in manufacturing. These workers produce and repair tools, dies, and special guiding and holding devices that enable machines to produce a variety of products we use daily – from clothing and furniture to heavy equipment and parts for aircraft. They may work in manufacturing plants that produce tools in house, or in machine shops that only produce specialized machine tools for other manufacturers.Toolmakers craft precision tools and machines that are used to cut, shape, and form metal and other materials. They also produce jigs and fixtures – devices that hold metal while it is bored, stamped, or drilled – and gauges and other measuring devices.

1 What do tool and die makers do? 2 Where do tool and die makers work? 3 What do tool and die makers craft?

2 Match the beginning of each sentence (1–8) with the correct ending (a–h).1 Routine maintenance a damaged.2 Heat and dust can b inspected every day.3 The generator should be c replaced it.4 The hose was split so we d follow the maintenance schedule.5 We removed the pump after it e repair it.6 We replaced the compressor f stopped working.

because we couldn’t g damage a machine.7 The gasket was h reduces accidents and injuries.8 It’s very important to

3 Choose the correct words to complete the sentences.1 In case / If a machine breaks, we try to repair it as quickly as possible.2 We always have a first aid kit in the workroom in case / if there’s an accident.3 When / In case there’s a computer problem, we call IT support.4 We have a fire extinguisher when / in case there is a fire.5 When / In case we get new tools or equipment, we are trained to use them properly.

4 Complete the sentences with and, but, or because.1 I have the instructions I don’t understand them.2 We’ve put away the tools cleaned the workshop floor.3 Tom remembered to bring his helmet he forgot his gloves.4 We couldn’t use the electric tools the generator was broken.

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1 Complete the text with the words listed below.

torch pressure hoses apparatus trolley oxygen

The 1 used in gas welding consists basically of an 2 source and a fuel gas source (usually cylinders), two 3 regulators and two flexible 4 (one of each for each cylinder), and a 5 . This sort of torch can also be used for soldering and brazing. The cylinders are often carried in a special wheeled 6 .

2 Match the types of arc welding (1–5) to their characteristics (a–e).1 bare metal arc welding a Non-consumable electrode, slow, high quality welds2 carbon arc welding b Consumable electrode, no flux or shielding gas3 flux cored arc welding c Carbon electrode4 tungsten inert gas welding d Continuous consumable electrode and shielding gas5 metal inert gas welding e Continuous consumable electrode filled with flux

3 Complete the sentences with much or many.1 How oxygen cylinders are there?2 We can’t weld here. There’s too water on the floor.3 We have 100 nuts and 200 bolts. There are too bolts.4 How time have we got?

4 Label the diagram of an angle grinder with the words listed below.

power cord wheel guard switch spindle lock button grinding wheel side handle

1 2 3 4 5 6

17Metal Mechanics

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6

1 Label the diagram of a soldering gun with the words in the list.

solder cord sleeve tip housing heating element pistol grip handle on/off switch soldering iron

1 2 3 4 5 6 7 8

2 Match the parts of a soldering gun (1–8) with functions (a–h).1 cord sleeve 2 housing 3 pistol grip handle 4 on / off switch 5 heating element 6 tip 7 solder 8 soldering iron

3 Match the wh- words (1–9) with the answers (a–i).1 When2 Where3 What4 Which5 Who6 Why7 How deep8 How much9 How long

4 Complete the sentences with the words listed below.

arc amps voltage polarity current electrical circuit

1 welding is a process used to join two pieces of similar metals together.2 A welder uses energy to heat metal until it is molten.3 The electrical potential or pressure that causes current to flow is called .4 The movement of charged particles in a specific direction is called and it is measured

in .5 deals with the direction of electron flow.6 The process or system above that deals with the path electricity follows is called a .

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a three yearsb the welderc a CAD programd North Carolinae 105 metresf in December 1998g the largest oneh to prevent an accidenti $45 million

a electric tool with a tip for heating a solder, used to join parts that can take only weak mechanical pressure.

b protective casing around the cable to lessen twisting and prevent wear.c case enclosing and protecting the device’s mechanism.d metal wire that, by fusing over a joint, joins two parts.e part shaped like a pistol grip so the wrist remains straight while holding

the tool.f metal part forming the end of the gun, used to heat a solder.g electrical resistor that quickly heats the tip.h switch controlling power.

19Metal Mechanics

Answer Key

Unit 11 1 power source 4 base material 2 electrode 5 power 3 arc

2 1 face shield 4 goggles 2 mitten 5 hand shield 3 gauntlet

3 1 helmet 4 contact 2 goggles 5 ventilation 3 cables

4 1 aluminium, copper, mild steel 2 copper, mild steel 3 aluminium, copper, brass 4 aluminium, copper, brass

Unit 21 1 g 2 d 3 e 4 h 5 c 6 f 7 b 8 a

2 1 I’m sorry but what did you say? 2 Excuse me can you repeat the number for me? 3 Could you spell that please?

3 wm e t a l c

r l d ou d u rs i r o n c rt e n s i l e t oi g i sn l ig e o

s t e e l n

4 1 eye safety shield 2 fire-resistant gauntlet gloves 3 safety shoes 4 clean fire-resistant clothing 5 hand-held helmet with filter lens 6 flame-proof skull cap

Unit 31 1 Soldering 4 Brazing 2 Tinning 5 Welding 3 Leading 6 Cutting

2 1 vaporizes 4 oxides 2 fume 5 gases 3 particulate 6 metal

3 1 filler rod 4 gas shielding 2 weld pool 5 nozzle 3 arc

4 1 A 2 A 3 D 4 D 5 A 6 A

Unit 41 1 torch body 2 armoured torch cable 3 gas supply tube 4 torch liner guiding filler wire 5 trigger 6 contact tip with nozzle 7 nozzle 8 insulated neck

2 1 processes 4 heat 2 join 5 resistance 3 welding 6 binding

3 s to l il w e l d i n gd a ne d i

b r a z i n g ni n gn gg

c u t t i n g

4 1 T 2 F 3 F 4 F 5 T

Unit 51 1 0.83% 2 It decreases. 3 Increased carbon increases hardness. 4 Tensile strength is reduced when the % of

carbon increases beyond 0.84%. 5 It decreases to its lowest point.

2 1 c 2 h 3 b 4 e 5 g 6 d 7 f 8 a

3 1 wide 4 deep 2 high 5 heavy 3 long

4 1 a 2 c 3 b

Unit 61 1 H 2 H 3 R 4 R 5 H 6 R

2 1 b 2 a 3 e 4 c 5 d

3 1 fall behind 4 chase up 2 carry out 5 catch up 3 hold up 6 get on with

4 1 b 2 c 3 a

Answer Key

20 Metal Mechanics

Unit 71 1 grinder 2 drill 3 saw

2 1 Have you finished welding? 2 We’ve done the grinding. 3 Have you and Ahmed painted it? 4 We haven’t painted it. 5 Have they built the base? 6 They haven’t finished the base.

3 1 a leaking discharge hose 2 check the valve discharge hose 3 three hours

4 1 welding and cutting 2 cutting 3 turning and shaping 4 grinding 5 drilling 6 designing 7 welding and cutting 8 welding

Unit 81 a four hundred and ninety b 5,000 c six thousand three hundred and forty-four d 10,000 e thirteen thousand four hundred and fifty f 300,000 g four hundred and sixty-five thousand h 7,000,000 i seventy-five million

2 1 Can I come in? 2 Can you pass me that hammer? 3 Can you help me carry this pipe? 4 Can I take off my hard hat?

3 1 b 2 c 3 d 4 a 5 e

4 1 bottle cart 2 pressure regulator 3 acetylene cylinder 4 welding torch 5 oxygen cylinder

Unit 91 1 g 2 kg 3 t 4 mm 5 cm 6 m 7 km

2 1 safe 2 Italian 3 calculator 4 hazards 5 employer

3 1 e 2 a 3 c 4 b 5 d 6 f

4 a 3 b 2 c 1 d 5 e 4

Unit 101 1 much 4 many 2 many 5 much 3 much 6 many

2 a 3 b 4 c 1 d 2 e 6 f 5

3 1 e 2 a 3 d 4 c 5 b

4 1 equipment 5 clothes 2 hazards 6 Smoke 3 cylinders 7 the material 4 the spark 8 skin

Unit 111 1 c 2 e 3 f 4 a 5 d 6 b

2 1 c 2 b 3 c 4 c

3 1 regulator 6 torch 2 gas valve 7 clamp 3 power source 8 remote control 4 coolant system 9 shielding gas 5 adaptor block

4 1 gas valve 4 clamp 2 Shielding gas 5 torch 3 Remote control 6 power source

Unit 121 1 connect 5 clamp 2 plug 6 AC 3 regulator 7 torch 4 foot pedal 8 tungsten

2 1 c 2 a 3 e 4 f 5 d 6 b

3 a rl p i p e e

s l a g go uy l

t o r c h ap o w e r t

g oa r

t u n g s t e n

4 1 longest 2 heavier 3 less 4 most 5 better 6 worse 7 worst

Answer Key

21Metal Mechanics

Unit 131 1 undesired oxidation of metals to oxides and

other compounds 2 rusting 3 copper and silver 4 25%

2 1 metal inert gas (MIG) or metal active gas welding (MAG)

2 constant voltage, direct current power source 3 globular, short-circuiting, spray and

pulsed-spray 4 to weld aluminium and other non-ferrous

materials 5 it allowed for lower welding time 6 the cost of inert gas limited its use in steels

Unit 141 1 gases 4 oxygen 2 welding 5 defects 3 atmospheric 6 problem

2 1 2,800 mm 4 2,058 mm 2 655 mm 5 550 mm 3 105 mm 6 275 mm

3 1 I was learning to weld when I burned my hand. 2 When I fell, I was climbing a ladder. 3 They were welding when the fire started. 4 Were you using the computer when the

power went off? 5 He wasn’t using the safety guard when he

cut his finger. 6 When we were eating lunch, the oxygen

bottle exploded.

4 1 the building of metal structures by cutting, bending, and assembling

2 sawing, shearing, chiseling, torching, CNC cutting

3 bending 4 structural steel and sheet metal

Unit 151 1 arc welding machine 2 work lead 3 welding curtain 4 ground clamp 5 electrode 6 electrode lead 7 electrode holder

2 1 an 2 the 3 a

3 1 metal 4 spark 2 corrosion 5 welding 3 accident

4 1 argon or helium 2 to join aluminium and magnesium

Unit 161 1 produce and repair tools, dies, and other

devices 2 manufacturing plants or in machine shops 3 precision tools and machines

2 1 h 2 g 3 b 4 c 5 f 6 e 7 a 8 d

3 1 If 4 in case 2 in case 5 When 3 When

4 1 but 3 but 2 and 4 because

Unit 171 1 apparatus 4 hoses 2 oxygen 5 torch 3 pressure 6 trolley

2 1 b 2 c 3 e 4 a 5 d

3 1 many 2 much 3 many 4 much

4 1 power cord 2 switch 3 side handle 4 wheel guard 5 grinding wheel 6 spindle lock button

Unit 181 1 housing 2 pistol grip handle 3 solder 4 soldering iron 5 cord sleeve 6 on/ off switch 7 heating element 8 tip

2 1 b 2 c 3 e 4 h 5 g 6 f 7 d 8 a

3 1 f 2 d 3 c 4 g 5 b 6 h 7 e 8 i 9 a

4 1 Arc 2 electrical 3 voltage 4 current; amps 5 Polarity 6 circuit

acknowledgements

The publisher would like to thank the following for their kind permission to reproduce photographs and other copyright.

Illustrations by: Mark Duffin p10; Oxford Designers and Illustrators pp1, 2, 3, 4, 5 (graph), 8, 9, 11, 15, 17, 18; Peter Bull Art Studio p7; Stefan Chabluk p14.

Photographs: Alamy Images pp5 (grinding/Riedmiller/Caro), (CAD screen/Dough Stanley), 6 (wood mill/Chrise Cheadle), (copmputer design/RightImage), 17 (Terence Hobgen); OUP pp5 (welding/Glowimages), 6 (drilling/Fotosearch), 10 (Glowimages).

Cover image by: OUP (Welder/Photodisc)

A0011823

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