METALS Learning Objectives: What is METAL? Different Types of Metals – Ferrous, Non-Ferrous, Alloys Main focus of Ferrous Metals Properties of Metals Characteristics of Ferrous Metals with examples Advantages/Disadvantages of Ferrous Metals

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.

METALS

METALS

METALS

METALS Ferrous Non-Ferrous Alloys Containing iron & Do not contain iron. A mixture of almost all are e.g. aluminium, metals, or a magnetic. copper, silver, gold, metal & small e.g. mild-steel, lid, tin etc. amount of cast-iron, tool- other substance Steel etc. Ferrous Alloys Non-Ferrous Alloys e.g. e.g. brass (copper + zinc) stainless steel bronze (copper + tin ) steel + chromium

METALS METALS & ALLOYS Metals 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.

PROPERTIES OF METALS Strength - The ability of a material to stand up to forces being applied without it bending, breaking, shattering or deforming in any way. Elasticity - The ability of a material to absorb force and flex in different directions, returning to its original position. Plasticity - The ability of a material to be change in shape permanently. Ductility - The ability of a material to change shape (deform) usually by stretching along its length.

PROPERTIES OF METALS 5. Tensile Strength – The ability of a material to stretch without breaking or snapping. Malleability - The ability of a material to be reshaped in all directions without cracking. Toughness - A characteristic of a material that does not break or shatter when receiving a blow or under a sudden shock. Conductivity - The ability of a material to conduct electricity.

PROPERTIES OF METALS 9. Hardness – The ability of a material to resist scratching, wear and tear & indentation.

FERROUS-METALS Mild Steel Composition: Iron alloy with 0.3% carbon Properties: Malleable and ductile, and therefore bends fairly easily Uses: nuts, bolts, screws, tubes etc. Methods of Identification Appearance: Bright drawn mild steel has a smooth, bright surface; black mild steel is covered with a blue-grey oxide Dropping: Gives out a ringing note Grinding: Gives off a shower of long white sparks Effect of Heating: Slightly tougher but little change

FERROUS-METALS 2. Tool Steel / cast steel / carbon steel Composition: Iron alloy with 0.5%-1.5% carbon Properties: Tough rather than hard, and fairly ductile Uses: Springs and most tools such as hammer heads, drills, chisels, shears etc Methods of Identification Appearance: Has a smooth skin of black oxide Dropping: Gives out a high ringing note Grinding: Moderate number of red sparks Effect of Heating: Becomes hard and brittle

FERROUS-METALS cast iron Composition: Iron alloy with 2%-4% carbon Properties: Brittle, snaps before it will bend. Strong in compression Uses: Vices, cylinder blocks for car engines, frames for most machines Methods of Identification Appearance: Grey with a granular surface Dropping: gives out a dull note Grinding: Gives off a few dull sparks Effect of Heating: No change

ADVANTAGES OF FERROUS METALS 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.

ADVANTAGES OF FERROUS METALS 2. High quality material readily available worldwide in various certificate grades. Speed of construction Versatility steel suits range of construction methods & sequences. Modification & repair Recycling Durability 8. Aesthetics steel has a broad architectural possibilities.

DISADVANTAGES OF FERROUS METALS Costly waste High cost of final finishing & polishing Environmental issue

RECAP Metal Different types of metals – ferrous, non-ferrous, alloy Properties of metals Strength Elasticity Plasticity ductility tensile strength malleability toughness conductivity hardness Examples of ferrous metals, uses, methods of identification Advantages Disadvantages Homework Metal Different types of metals – ferrous, non-ferrous, alloy Properties of metals Strength Elasticity Plasticity ductility tensile strength malleability toughness conductivity hardness