Didactic unit # 4 metals part i

TECHNICAL USE MATERIALS (II): METALS

© Federico Fernández Herrera

ENGLISH BILINGUAL 2º E.S.O. TECHNOLOGY

DIDACTIC UNIT # 4

INDEX:

Metal featuresMetals: ferric vs. non ferric

pure vs. alloys Production of metalsWorking with metalsEnvironmental impact

Metal features:

High mechanical resistanceHigh thermic and electric conductivityHigh melting pointHigh densityHigh ductility and malleabilityEasy to recycleSome are magnetic

Cast Iron Steel Cu Al Ti

Traction (Mg/in2) 18 70 18 10 70

Density (kg/dm3) 7,6 7,8 8,8 2,7 4,5

Melting point (ºC) 1.100 1.500 1.080 660 1.800

Metals: ferric vs non ferric

World Metal Production

o Ferric Metals: iron and its alloys. o Non-Ferric Metals: they do not contain iron.

Iron is the most used metal in the world

Metals: o Ferric Pure iron Fe Alloys Fe+C Soft iron

Steel Cast iron

Non-Ferric Pure Copper Cu» Aluminum Al» Titanium TiOther (Sn, Zn, Mg, Ag, Au, etc)

Ferric Metals

Magnetic, abundant, fragile, brittle, easy to get rusty.

Iron (Fe) pure

Iron (Fe) and carbon (C) alloys: Soft iron <0,1 % CSteel (0,1 - 2) % CCast iron (2 – 5) % C

Steel ( 0,1%<C<2% )It´s the most used ferric alloy due to its good features.Ductile and malleable.High mechanical resistance.The amount of carbon increases hardness but fragility too.

Steel mixed with other metals increases endurance (vanadium) and becomes stainless (chrome and nickel).

Ferric Metals (II): Ferric Alloys

Cast Iron ( 2%<C<5% )

Hardness, ductility and melting point: less than steel. Fragility: more

It´s used to produce complicated parts by sand casting and to make hard tools like rasps.

Ferric Metals (II): Ferric Alloys (II)

Non-Ferric Metals: Pure Metals Copper Cu

Tin Sn

•Red coloured if OFC, green, black.•High thermal and electric conductivity•Corrosion resistant•High ductility and easy to weld

• Shiny white coloured•Corrosion resistant•Low melting point

Zinc Zn

Aluminium Al

•White coloured•High corrosion resistance

• White shiny coloured• Light• Non toxic• Stainless (anodization)

Non-Ferric Metals (II): Pure Metals (II)

Magnesium Mg

Titanium Ti

•Very light•Expensive•Violent reaction with oxygen

•Very expensive•Like steel but lighter•Biocompatible

Non-Ferric Metals (II): Pure Metals (II)

Gold Au

Lead Pb

•The most malleable and ductile metal•High corrosion resistance•High thermal and electric conductivity•Expensive, solid value.

•Grey colour•Very soft•Low melting point•Ductile and malleable•Very toxic

Non-Ferric Metals (III): Pure Metals (III)

Brass (Cu+Zn)

Bronze (Cu+Sn)

•Yellow, dark red coloured•Very ductile and malleable•Good tensile endurance

•Yellow, dark green coloured•More endurance than brass•Very corrosion resistant•Musical features•Good for casting and molding

Non-Ferric Metals (IV): Alloys

Aluminum, Copper & Magnesium

Magnesium & Aluminum

Titanium & Aluminum

•Lightness and more endurance than pure aluminum.

•This alloy is more resistant than each metal.

• Cheaper than pure titanium parts.

Non-Ferric Metals (V): Alloys (II)