2. Metals can be either ferrous or non-ferrous. Ferrous metals contain iron while non-ferrous metals do not.Metals can be either ferrous or non-ferrous. Ferrous metals contain iron while non-ferrous metals do not. Both ferrous and non-ferrous metals are divided into pure metals and alloys. A pure metal is an element - eg iron, copper, gold - unalloyed (not mixed) with another substance. An alloy is a mixture of two or more elements (eg, iron and carbon) to make another metal with particular properties (eg steel)Both ferrous and non-ferrous metals are divided into pure metals and alloys. A pure metal is an element - eg iron, copper, gold - unalloyed (not mixed) with another substance. An alloy is a mixture of two or more elements (eg, iron and carbon) to make another metal with particular properties (eg steel)

3. FERROUS ALLOY The properties of steels, determined by dispersion strengthening, depend on theThe properties of steels, determined by dispersion strengthening, depend on the amount, size, shape, and distribution of cementite (fe3c). These factors are controlled by alloying and heat treatment.These factors are controlled by alloying and heat treatment.

4. FERROUS ALLOY Those with iron as prime constituent (except for high alloy steel) Important as engineering construction material (especially steel fe-c) is because: 1)abundant within the earth-crust – low cost 2)easier to be produced 3) good strength toughness and ductility 4) versatile – wide range of mechanical and physical properties

5. FERROUS ALLOY Can be alloyed and heat treated to get desired mechanical properties Can be alloyed and heat treated to get desired mechanical properties Alloying is combining or mixing other material like carbon or other metals to iron Alloying is combining or mixing other material like carbon or other metals to iron Heat treatment is a process of heating and cooling a metal to achieve specific microstructure which in turns display specific mechanical properties (e.g. Quenching austenite gives martensite witch be treated to martensite which is can heat (tempered) produced tempered more ductile Heat treatment is a process of heating and cooling a metal to achieve specific microstructure which in turns display specific mechanical properties (e.g. Quenching austenite gives martensite witch be treated to martensite which is can heat (tempered) produced tempered more ductile

6. NameCompositionProperties and characteristics Principal uses Cast ironAlloy of iron and 2-5% carbon, 1-3% silicon and traces of magnesium, sulphur and phosphorus. Hard skin, softer underneath, but brittle. It corrodes by rusting. Parts with complex shapes which can be made by casting Mild steelAlloy of iron and 0.15 - 0.3% carbon Tough, ductile and malleable. Good tensile strength, poor resistance to corrosion General-purpose engineering material Medium carbon steel Alloy of iron and 0.35 - 0.7% carbon Strong, hard and tough, with a high tensile strength, but less ductile than mild steel. Springs; any application where resistance to wear is needed Composition, properties and uses of some common ferrous metals

7. High carbon steel Alloy of iron and carbon: 0.7 - 1.5% carbon Even harder than medium carbon steel, and more brittle. Can be heat-treated to make it harder and tougher Cutting tools, mechanical elements Stainless steel Alloy of iron and carbon with 16-26% chromium, 8-22% nickel and 8% magnesium Hard and tough, resists wear and corrosion Cutlery, kitchen equipment High speed steel Alloy of iron and 0.35 - 0.7% carbon (medium carbon steel) with tungsten, chromium, vanadium, and sometimes cobalt Very hard, high abrasion- and heatresistance Cutting tools for machines

8. NON-FERROUS ALLOY A non ferrous alloy is one that does not contain iron. It includes metals and alloys of aluminum, brass, bronze, copper, lead, tin, titanium, zinc, nickel, cobalt, tungsten, molybdenum, magnesium, precious metals and refractory metals.A non ferrous alloy is one that does not contain iron. It includes metals and alloys of aluminum, brass, bronze, copper, lead, tin, titanium, zinc, nickel, cobalt, tungsten, molybdenum, magnesium, precious metals and refractory metals. They are used in construction and manufacture of medical devicesThey are used in construction and manufacture of medical devices

9. Name CompositionProperties and characteristics Principal uses AluminiumPure aluminium (an element) Good strength-to-weight ratio, light, soft, ductile, good conductor of heat and electricity Kitchen equipment, window frames, general cast components CopperPure copper (an element) Malleable and ductile, good conductor of heat and electricity, resistant to corrosion Water pipes, electrical wire, decorative goods ZincPure zinc (an element) Weak metal, extremely resistant to corrosion Usually used for coating steel to make galvanised items Composition, properties and uses of some common non-ferrous metals:

10. BrassAlloy of copper and zinc Resistant to corrosion, fairly hard, good conductor of heat and electricity Cast items such as water taps, ornaments BronzeAlloy of copper and tin Fairly strong, malleable and ductile when soft Decorative goods, architectural fittings TinPure tin (an element)Soft, weak, malleable, ductile and resistant to corrosion Usually used for coating steel to form tinplate