Mechanical Engineering Mechanical Engineering TechnologyTechnology

Lesson Lesson

Topic: Topic: Common MetalsCommon Metals

Have fun learningHave fun learning

Objectives of this Objectives of this LessonLesson

By the end of this lesson you should be able By the end of this lesson you should be able to:to:

1)1) Define the three main groups of common Define the three main groups of common metalsmetals

2)2) Identify some common metalsIdentify some common metals

3)3) State the colour, properties and uses of State the colour, properties and uses of common metalscommon metals

Common MetalsCommon Metals• The importance of metals to man in The importance of metals to man in

today's world cannot be overemphasized today's world cannot be overemphasized because we use them in our everyday because we use them in our everyday life.life.

• Metals are divided into three main Metals are divided into three main groups;groups;

• Ferrous, Ferrous, • Non-ferrousNon-ferrous• Alloys.Alloys.

Ferrous MetalsFerrous MetalsThese contain These contain

mainly iron and they mainly iron and they rust easily when rust easily when exposed to air.exposed to air.

Non-Ferrous Metals• These contain little or These contain little or no iron and they do not no iron and they do not rust when exposed to rust when exposed to air.air.

Space rocket

AlloysAlloys• These are a mixture of These are a mixture of two or more metals. two or more metals. They may be ferrous or They may be ferrous or non- ferrous.non- ferrous.

Art work

Examples of Ferrous Examples of Ferrous MetalsMetals

• Cast ironCast iron• Wrought ironWrought iron• Mild steelMild steel

Wrought iron bridge

Cast ironCast ironGray or white in colourGray or white in colourVery brittle with a hard outer coreVery brittle with a hard outer coreUse for making machine slide-Use for making machine slide-

ways, beds, vice and support ways, beds, vice and support brackets. brackets.

Cast iron vice

Wrought ironWrought iron• Light grey in colourLight grey in colour• Very malleable and ductileVery malleable and ductile• Used for making grill gates, Used for making grill gates,

crane hooks and bridges.crane hooks and bridges.

Wrought iron grill

Mild steelMild steelGray in colour, shows Gray in colour, shows

silvery when machinedsilvery when machinedVery ductile and malleableVery ductile and malleableUsed for making nuts, gears, Used for making nuts, gears,

bolts, grill, buildings and for bolts, grill, buildings and for general engineering general engineering purposespurposes Spur gears

Activity # 1Activity # 1• INSTRUCTION: Match the following items correctly by writing INSTRUCTION: Match the following items correctly by writing

the letter A, B or C in the appropriate box on the right.the letter A, B or C in the appropriate box on the right.

Metals that do not contain iron

Mixture of metals

alloys

Non-ferrous

ferrous

Metals that contain iron

Activity # 1 Answers

A

B

C

Examples of non-ferrous metals

AluminiumCopperLeadTinZinc

Aluminium blocks in stock

Aluminium Light gray in colour,shows silvery when

machined Very ductile,malleable,soft,light in weight and

is a good conductor of heat and electricity Used for making pots, pans, furniture, aircraft

parts, car parts and television antennas.

Aircraft manufacturing

Copper Brownish pink in colourBrownish pink in colour A very good conductor of heat and A very good conductor of heat and

electricity, malleable and ductileelectricity, malleable and ductile Used for making electrical wires, Used for making electrical wires,

soldering iron, electrical coils andsoldering iron, electrical coils and tubes.tubes.

Copper coil

LeadLead• Bluish grey in colourBluish grey in colour• Poisonous, has a dull metallic luster, Poisonous, has a dull metallic luster,

plastic- like, resistant to acids and very plastic- like, resistant to acids and very heavyheavy

• Used for making weights, containers Used for making weights, containers for acids and car batteries.for acids and car batteries.

Car battery

TinTin• Silvery in colourSilvery in colour• Not used much on its own, very Not used much on its own, very

malleable and ductilemalleable and ductile• Used as a coating for steel to make tin Used as a coating for steel to make tin

plate which is then used to make food plate which is then used to make food stuff container for milk, mackerel, stuff container for milk, mackerel, drinks and juice.drinks and juice.

ZincBluish white in colourSomewhat hard and brittle.Like tin, not used much on its own. Used

as a coating for mild steel (galvanizing) which is used for making sheets for roofing

Examples of Alloys• Brass• Bronze

Bicycle-made using alloys

BrassBrass• Brass is an alloy of copper and zincBrass is an alloy of copper and zinc• Yellow in colour, malleable and is a Yellow in colour, malleable and is a

good conductor of electricity.good conductor of electricity.• Used for making screws, door locks, Used for making screws, door locks,

jewellery and some electrical jewellery and some electrical components. components.

BronzeBronze

• Bronze is a mixture of copper and tinBronze is a mixture of copper and tin• Dark yellow in colour, ductile and is a good Dark yellow in colour, ductile and is a good

conductor of heat.conductor of heat.• Used for making water pipe fittings, gas Used for making water pipe fittings, gas

welding equipment, weapons, medals and welding equipment, weapons, medals and trophiestrophies

Early weapons

QuizQuizRead the statements below. If the statement is Read the statements below. If the statement is

“true’’ write “T”, if “false" write “F”.“true’’ write “T”, if “false" write “F”.

1)1) Ferrous metals contain no iron. Ferrous metals contain no iron. 2)2) Alloys contain two or more metals.Alloys contain two or more metals.3)3) Cast iron is a ferrous metal. Cast iron is a ferrous metal. 4)4) Copper is a poor conductor of heat and Copper is a poor conductor of heat and

electricity. electricity. 5)5) Lead is a poisonous metal. Lead is a poisonous metal.

For answers click here For answers click here

Answers

Activity # 1 AnswersActivity # 1 AnswersMatching items

Metals that do not contain iron

Mixture of metals

alloys

Non-ferrous

ferrous

Metals that contain ironA

B

C

C

B

A

Answers for quiz

• 1 F• 2 T• 3 T• 4 F• 5 T

Congratulation

Assignment • State the properties, appearance and uses of

gold.• This should be typed• No more than two pages• Should contain at leased one picture• Due date: one week from now.

Lesson summary

• From this lesson we learnt that common metals are very important in our everyday life.

• Metals are used in the transportation industry in manufacturing motor vehicle, aircrafts, etc.

• Used for making kitchen utensils and many appliances.

• We are able to identify metals by their colours and properties.

references• tubeshttp://www.bbsheetmetal.com/product.php?prID=19• 2005 Encarta DVD library• Thomas G. H. Metalwork Technology, Metric edition.

ASSIGNMENT

• Research on a mechanical engineer• Find a picture of the person• The product that the person designed

End of lesson

• I hope that you have found it interesting and informative.