WHAT ARE METALSLearning Objectives:

•Defining METAL? •Different Types of Metals – Ferrous, Non-Ferrous, Alloys•Main focus of Ferrous Metals•Properties of Metals•Characteristics of Ferrous Metals with daily examples•Advantages/Disadvantages of Ferrous Metals

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Contd..METALS•Metals are… Solid at room temperature, except

mercury, which is liquid !

•Metals have… very high melting point.

•Metals are… shiny when they cut.

•Metals are… good conductors of heat and electricity.

•Metals are… usually strong & malleable so they can be hammered into shape.

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METALS in Periodic Table

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METALS

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METALS

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METALS

Ferrous Non-Ferrous AlloysContaining iron & Do not contain iron. A mixture ofalmost all are e.g. aluminium, metals, or amagnetic. copper, silver, gold, metal & smalle.g. mild-steel, lid, tin etc. amount ofcast-iron, tool- other substanceSteel etc.

Ferrous Alloys Non-Ferrous Alloyse.g. e.g. brass (copper + zinc)stainless steel bronze (copper + tin )steel + chromium

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METALSMETALS & ALLOYSMetals are available in pure or alloy form.

Pure Metals such as pure aluminium or pure copper, contain only one type of metal. They are not mixed with any other metal.

Alloys are mixture of two or more pure metals.

Alloys tend to have better strength properties than pure metals.

Alloys and pure metals often have special physical properties. 12:02 7ص

PROPERTIES OF METALS1. Strength - The ability of a material to stand up to

forces being applied without it bending, breaking, shattering or deforming in any way.

2. Elasticity - The ability of a material to absorb force and flex in different directions, returning to its original position.

3. Plasticity - The ability of a material to be change

in shape permanently.

4. Ductility - The ability of a material to change shape (deform) usually by stretching along its length.

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PROPERTIES OF METALS5. Tensile Strength – The ability of a material to

stretch without breaking or snapping.

6. Malleability - The ability of a material to be reshaped in all directions without cracking.

7. Toughness - A characteristic of a material that does not break or shatter when receiving a blow or under a sudden shock.

8. Conductivity - The ability of a material to conduct electricity.

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PROPERTIES OF METALS9. Hardness – The ability of a material to resist

scratching, wear and tear & indentation.

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FERROUS-METALS1. Mild Steel

Composition: Iron alloy with 0.3% carbonProperties: Malleable and ductile, and therefore bends fairly easilyUses: nuts, bolts, screws, tubes etc.

1. Methods of Identification

Appearance: Bright drawn mild steel has a smooth, bright surface; black mild steel is covered with a blue-grey oxideDropping: Gives out a ringing noteGrinding: Gives off a shower of long white sparksEffect of Heating: Slightly tougher but little change

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FERROUS-METALS2. Tool Steel / cast steel / carbon steel

Composition: Iron alloy with 0.5%-1.5% carbonProperties: Tough rather than hard, and fairly ductileUses: Springs and most tools such as hammer heads, drills, chisels, shears etc

Methods of Identification

Appearance: Has a smooth skin of black oxideDropping: Gives out a high ringing noteGrinding: Moderate number of red sparksEffect of Heating: Becomes hard and brittle

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FERROUS-METALS3. cast iron

Composition: Iron alloy with 2%-4% carbonProperties: Brittle, snaps before it will bend. Strong in compressionUses: Vices, cylinder blocks for car engines, frames for most machines

Methods of Identification

Appearance: Grey with a granular surfaceDropping: gives out a dull noteGrinding: Gives off a few dull sparks

Effect of Heating: No change 12:02 13ص

ADVANTAGES OF FERROUS METALS1. High strength to weight ratio

it minimise the substructures cost, which beneficial in poor ground condition. E.g. The Newark Dyke Rail Bridge – comprises 77 meter long, 11.25 meter wide bowstring with 820 tonnes of S355 steel. This bridge use IMD (Interactive Model Technique) – reduced the time required to assess the dynamic response of the structure.This bridge was the first UK steel bridge to be designed for the next generation of 225 km/hr trains.

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ADVANTAGES OF FERROUS METALS2. High quality material

readily available worldwide in various certificate grades.

3. Speed of construction

4. Versatilitysteel suits range of construction methods & sequences.

5. Modification & repair

6. Recycling

7. Durability

8. Aestheticssteel has a broad architectural possibilities.

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DISADVANTAGES OF FERROUS METALS1. Costly waste2. High cost of final finishing & polishing3. Environmental issue

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REVIEW• Metal• Different types of metals – ferrous, non-ferrous, alloy• Properties of metals

StrengthElasticityPlasticityductilitytensile strengthmalleabilitytoughnessconductivityhardness

• Metal• Different types of metals – ferrous, non-ferrous, alloy• Properties of metals

StrengthElasticityPlasticityductilitytensile strengthmalleabilitytoughnessconductivityhardness

• Examples of ferrous metals, uses, methods of identification• Advantages• Disadvantages

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Mid Term Exam

• Monday 2/10/2012, from 15 to 17

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