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© Boardworks Ltd 20051 of 17 Resistant Materials Metals These icons indicate that teacher’s notes or useful web addresses are available in the Notes Page.

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Presentation on theme: "© Boardworks Ltd 20051 of 17 Resistant Materials Metals These icons indicate that teacher’s notes or useful web addresses are available in the Notes Page."— Presentation transcript:

1 © Boardworks Ltd of 17 Resistant Materials Metals These icons indicate that teacher’s notes or useful web addresses are available in the Notes Page. This icon indicates that the slide contains activities created in Flash. These activities are not editable. For more detailed instructions, see the Getting Started presentation. © Boardworks Ltd of 17

2 © Boardworks Ltd of 17 Learning objectives © Boardworks Ltd of 17 Learning objectives To know where metals come from and how they are obtained. To understand the differences between, and properties of, ferrous and non-ferrous metals and alloys. To understand how the properties of different metals make them suitable for different uses. To know how the properties of metals can be altered by heating.

3 © Boardworks Ltd of 17 Metals are part of the earth’s crust. Economic, chemical and technological problems have to be solved to obtain them. How desirable a metal is often depends on how scarce it is. Gold diggers dig up tonnes to obtain a few grams, whereas there is so much iron that materials technologists are only interested if they can obtain hundreds of kilograms from each tonne of ore. Where do metals come from?

4 © Boardworks Ltd of 17 Copper ore is mined, then washed to remove other minerals and unwanted materials. It is heated in a furnace and the molten copper is run off. This process is known as smelting. Where do metals come from? Pure metals like copper form part of the earth’s crust as metal ore.

5 © Boardworks Ltd of 17 Extracting metals – smelting

6 © Boardworks Ltd of 17 Aluminium is the most plentiful metal found in the earth’s crust, and is in high demand because it is both light and strong. Aluminium is extracted from aluminium oxide (bauxite) by electrolysis. Electricity passes between the electrodes and pure aluminium forms at the cathode. Extracting metals – electrolysis molten aluminium metal cathode lining carbon anode

7 © Boardworks Ltd of 17 Ferrous metals are metals which contain iron. They will corrode if unprotected. Ferrous metals will be attracted by a magnet. Non-ferrous are metals which do not contain iron. Pure metals such as aluminium, copper, tin and lead are non- ferrous, and do not rust. Ferrous and non-ferrous metals Metals can be classified into three groups: ferrous metals, non-ferrous metals and alloys. Alloys are metals which are a mixture of two or more metals, benefiting from the properties of both. For example, brass is an alloy of copper and zinc.

8 © Boardworks Ltd of 17 Types of metals

9 © Boardworks Ltd of 17 Examples of ferrous metals

10 © Boardworks Ltd of 17 Non-ferrous metals

11 © Boardworks Ltd of 17 Examples of alloys

12 © Boardworks Ltd of 17 Random alloy generator

13 © Boardworks Ltd of 17 Heat treatment – annealing

14 © Boardworks Ltd of 17 Heat treatment – hardening steel

15 © Boardworks Ltd of 17 Heat treatment – tempering

16 © Boardworks Ltd of 17 Metals are commercially available in a range of stock shapes and sizes. Market forms of metals channel angle square tube round tube flat strip sheet round rod square rod hexagonal rod octagonal rod

17 © Boardworks Ltd of 17 Key points © Boardworks Ltd of 17 Key points Metals are extracted from the earth’s crust. Iron ore is smelted to obtain iron, while aluminium is obtained by electrolysis. Ferrous metals come from iron ore and include cast iron and steel. Non-ferrous metals include aluminium, copper and tin. Alloys such as brass and stainless steel are formed from two or more metals and other elements. Heating metals alters their properties. Annealing involves heating a metal and then allowing it to cool, which makes the metal more workable. Tempering steel makes it less brittle.


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