metals

MetalsBy: Ariadna Riera,

Maria LorenzoAnd

Marcel Sales

Marcel

THE PROPERTIES OF METALS: Hard Non-adhesive

Cold and smooth

Often shiny

Vocabulary:-Smooth: A surface that is not rough-Shiny: reflects light of a smooth or polished surface

Ari

PHYSICAL PROPERTIES:

Strong: Can resist forces while not becoming deformed easily. Ex. Tensile…

Ductile and malleable: Can be made into wire or thin sheets.

Tough: Don’t break esaily. Maria

Electrical, thermal and acoustic conductivity: They’re good conductors for electricity, heat and sound.

Magnetic: Magnets attracts some metals.

Marcel

Fusible: Can be easily welded to other metallic objects.

Expansion and contraction: When the temperature rises, they expand and when it falls, they contract.

Plastic and elastic: Some metals are elastic, they can bend and return to their original shape when they are affected by external forces. Ari

CHEMICAL PROPERTIES:Oxidation: React with oxygen

in water and air

ECOLOGICAL PROPERTIES:Recyclable and reusable: Most metals are

recyclabe: when they have been used, they can be processed to be used again.

Toxic: Some metals, such as lead or mercury, present a danger to human beings and the environment.

Maria

Where and how metals are obtained?

Metals are taken from minerals contained in rocks.

1-SURFACE MINING: is used when the mineral layer is near the surface.

2-UNDERGROUND MINING: is used when the mineral is deep below the surface.1 2

Marcel

Ferrous materialsCHARACTERISTICS:

-Common.

-Inexpensive to extract.-Need processing to produce pure iron.-Used to make alloys.

ALLOY: is a mixture of two or more chemical elementsTHERE ARE THREE TYPES OF ALLOYS:

1- Pure iron.2- Steel.3-Cast iron.

Ari

SteelAlloy steels

Silicon: makes the alloy magnetic and improves elasticity.Manganese: makes the alloy harder and heat-resistant.Nickel: improves strength and prevens corrosion.Tungsten: makes the steel harder, more heat-resistant, and prevens corrosion.Chrome: makes the alloy harderand tougher and more rustproof.Lead: makes it easier to cut steel with machine

tools.Maria

-The steelmaking process1- The iron mineral is washed to remove impurities.2- It is crashed and sieved (the gangue is separeted from

the ore)3- The iron mineral (ore) is mixt with carbon and limestone.4- This is smelted at a temperature of over 1500°C in a

blast furnace.5- Pig iron is obtained (molte iron mixt with carbon and

impurities)

Marcel

HEAVY METALS LEAD:

SOURCE CHARACTERISTICS USES

Galena

- Silvery grey- Soft and malleable.- Is very toxic when

lead fumes are inhaled.

Batteries, protective measures against nuclear radiation.An additive in glass to give hardness and add wight.

Ari

Tin:SOURCE CHARACTERISTIC

SUSES

Casstierite - Shiny white.- Very soft.- Does not oxidise at

room temperature.

Tin foil and tin plate (a sheet of steel coated on both sides with a thin layer of tin).Alloyed with lead, it is used for soft soldering

Maria

Zinc:SOURCE CHARACTERISTICS USES

Sphalerite and hemimorphite

-Bluish grey-Shiny-Weak at low temperatures-Not very hard

Roofing, plumbing and in the car industry. A layer of zinc is used on other materials to stop corrosion

Marcel

Cooper:SOURCE CHARACTERISTICS USES

Cuprite, chalcopyrite and malachite

-Corrodes of oxidises very easly

Electrical wire, telephone lines, pipes, radiators, as decoration and in architecture jewellery and handicrafts

Ari

Bronze:SOURCE CHARACTERISTICS USES

Alloy cooper and tin -Resistant to wear and corrosion

Boat propellers, filters, church bells, sculptures, nuts, bearings and cogs.

Maria

Brass:SOURCE CHARACTERISTICS USES

Alloy cooper and zinc -Very resistant to corrosion

Handcrafts, jewellery, plumbing, capacitors and turbines

Marcel

Shaping techniquesShaping:

Rolling

Extrusion

Forging

Press forging

Punching

Bending

Wire drawingAri

Shaping techniquesPowder metallurgy:

This progect have five states:The metal is ground into powder.It is pressed into steel dies.It is heated to a temperature close to 70% of

the metal’smelting point.Preassure is applied to produce the required

dimensions.The object is left to cool.

Maria

Shaping techniquesCasting: used to change the dimensions of

the object.The metals is heated to the casting processThe liquid metal is poured into the mouldThe mould and metal are left to cool until the

metal has solidified.The solidified piece is extracted from the

mould

Marcel

Permanent joinRivet

Press fit join

Adhesive

Welding and soldering

Ari

Temporary joinsNuts and bolts

Screws

Threated stay bolts

Keyed joints

Splined shafts

Sliding joinsMaria

FinishiesFinishing is for:

Removing surface imperfectionsPolishingProtecting metals from water and corrosion

Finishing techniques:GrindingLappingPolishingBuffingCoatings

Marcel