Exam revision75% - Core technical principles

25% - Specialist subject – Woods and Manufactured boards

Hardwoods Softwoods Manufactured boards

Provide a minimum of 6 Provide a minimum of 3 Provide a minimum of 6

1.Define: Coniferous and Deciduous2.In your book, draw out a cross section showing how (3 ply)

plywood is made.

1.Find examples of: Smart materials and Composite materials (3 of each)

2. Energy and Power – Renewable and non-renewable. What are they? Find examples.

3. Why would consumers choose metal products to be made in Third world countries?

4. What would be the environmental impact when making products like the ‘Sky hook’ or ‘Rod the dog’?

Starter• Can you name the metals

Ferrous

C --- I---

M --- S----

Non Ferrous Metals

A--------

D--------

C-----

B----

P-----S-----

Alloys

S -------- S----

High Speed S ----

High Tensile S----

Remember to put the date.

BONUS : What is the difference between a Ferrous and Non-Ferrous Metal ? What is an alloy.

Cast Iron

Mild Steel

Medium Carbon Steel

High Carbon Steel

Duralumin

Copper

Brass

Bronze

Pewter

Silver

Stainless Steel

High Speed Steel

High Tensile Steel

METALS

All metals can be classified as either Ferrous or Non-ferrous

Ferrous

•These are metals which contain iron.

•All ferrous metals are magnetic

Give little resistance to corrosion (they rust)

Example: Steel, cast iron

Non-Ferrous

•These are metals which do not contain any iron.

•They are not magnetic

Usually more resistant to corrosion than ferrous metals.

Example : Aluminium, copper, zinc, gold.

KEYWORDS KEYWORDS

Alloys

Alloy

Metal blended with some other substance to give it special qualities.

Qualities such as resistance to corrosion, greater hardness, or strength.

Examples of alloys are Brass (Copper and Zinc)Bronze (Copper and Tin)

Pure Metals

A pure metal only consists of a single element.

Examples are:-aluminium, copper, iron, lead, zinc, tin, silver and gold.

OREA solid natural material from which metal is extracted (removed)

KEYWORDS

What to consider when choosing metals

• Elasticity (goes back to its original shape)• Ductility (can be stretched without breaking)• Malleability (can be stretched, hammered, pressed into shape)• Hardness ( does it scratch easily)• Work hardness (structure of metal changes when hit)• Brittleness (breaks easily without bending)• Toughness (resistance to fracture when stressed)• Tensile strength (strong if stretched)• Compressive strength (strong if squashed)• Stock sizes / Stock forms

Learn what these words mean

FerrousMild Steel

Properties:

• Iron mixed with 0.15-0.3% Carbon• Tough• Ductile• Malleable• Good tensile strength

Application

Nuts, bolts, car bodies, gates

DISADVANTAGE

Rusts easily

FerrousCast Iron

Properties:

• Very strong in compression• Hard skin, but brittle underneath• Heavy

Application

Metal work vicesBrake DiscsCar cylinder blocksManhole covers

DISADVANTAGE

Rusts easilyBrittle

FerrousTool Steel

Properties:ALSO KNOWN AS ‘Medium’ or ‘High Carbon’ steel • Up to 15 % carbon content.• Strong (can withstand force)• Very hard (do not scratch or wear) Application

Hand tools e.g. Chisels, screwdrivers, hammers, saws, garden tools, springs

DISADVANTAGE

Not very ductile (ability to stretch without breaking)

FerrousStainless Steel

Properties:An alloy of iron with 18% chromium, 8% nickel and 8% magnesium Very resistant to wear and tear DOES NOT CORRODE Ductile Malleable No flavour Easy to clean Non toxic

Application

Cutlery, kitchen fittings (sinks,taps), tea pots, surgical instrumentsDISADVANTAGE

Hard to work with

FerrousHigh Speed Steel

Properties:High content of tungsten, chromium and vanadium• Resistant to wear • Hard (resistant to scratching and

wear)• Tough (resistant to breaking

bending, deforming)• Compressive strength (strong under

pressure)

Application

Drill bits, lathe tools, milling cutters – where high speeds and temperatures are created

DISADVANTAGE

Brittle (breaks easily without bending)

Non -FerrousAluminium

Properties:• Light grey in colour• Can get mirror finish by polishing• Light in weight • Malleable• Does not rust• Conducts heat• Non toxic• No taste• Chemical resistant• Does not stain

ApplicationCooking foilSaucepansChocolate wrappersWindow framesLadders

DISADVANTAGEMalleable (soft)

Non -FerrousCopper

Properties:Reddish/Brown colourDuctileMalleableConducts heatConducts electricity

Application

PlumbingDomed roofs (turns green)Printed circuit boards

DISADVANTAGE

Turns greenMalleable (soft)

Non -FerrousTin

Properties:Bright silver in appearanceDuctileResistant to corrosionMalleableDoes not chemically react to food.

Application

A coating on food cans that are made of steel.

Note: Some cans are now made from aluminium as it can be re-cycledDISADVANTAGE

Soft (an actual tin can would dent to easily)

Non -FerrousZinc

Properties:VERY resistant to corrosion from moisture

**** Often used as a coating on other metals e.g. Mild steel

ApplicationCoating on hand rails, watering cans, screws.

Is sometimes used in roofing.

DISADVANTAGEVery weak

Non -FerrousBrass

Properties:Yellow metal (65% copper, 35% zinc)HardAntimicrobialEasy to machineElectrical conductorThermal conductorNo tasteNon toxicDoes not rustCan be easily soldered

Application

Brass instrumentsDecorative metal work

Non -FerrousPewter

Properties:Mainly tin (small amount of antimony and copper)Now available as a lead free alloy.Can be easily castPolishes wellCan get a mirror like finishMalleableLow melting point

ApplicationJewelleryCandlesticksTankardsDISADVANTAGE

Expensive