Metals Topic Revision

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  • Created by: hgrattan
  • Created on: 07-12-15 22:11
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Hardness ­ resistance to scratching, cutting and wear.
Elasticity ­ ability to get back to its original shape after it has been misshapen.
Malleability ­ the ability to be easily pressed, spread and hammered into shapes.
Work hardness ­ when the structure of the metal alters as a result of consistent strain.
Ductility ­ the ability to be stretched without breaking.
Brittleness ­ it will break easily without bending.
Compressive strength ­ very strong under pressure.
Tensile strength ­ very strong when stretched.
Toughness ­ resistance to breaking, bending, or deforming.
Alloys are substances that contain two or more different metals and occasionally other elements. The
metals are carefully chosen and mixed to achieve specific properties these include reducing the melting
point making the alloy light weight ect.
Ferrous metals contain iron . Examples are cast iron,mild steel,medium carbon steel ,high carbon steel,
stainless steeland high speed steel . Consequently they tend to rust / suffer from corrosion. They need
protecting with paint, oil or a surface finish. They react to a magnet.
Abraham Darby 1st (1678 ­1717) -Developed a technique of producing `pig iron' in large
quantities, through casting molten iron, crucial to the industrial revolution. He developed sand
casting techniques, making it possible to produce cast products of a high standard.
Mild Steel
Carbon 0.1 - 0.3% / Iron 99.9 - 99.7%
Alloy of carbon and iron. Tough. High tensile strength. Can be case hardened. Rusts very easily,
unless the surface is protected from moisture.
Most common metal used in school workshops. Used in general metal products and engineering.
Carbon Steel
Carbon 0.6 - 1.4% / Iron 99.4 - 98.6%
Alloy of iron and carbon. Higher carbon content than mild steel. Tough and strong. Carbon steel
can be heat treated e.g. hardening and tempering.
Used for cutting tools such as drills and lathe tools.
Stainless Steel
Alloy of iron, nickel and 10.5% to 11% chromium.
Tough, resistant to rust and stains. Does not corrode.
Cutlery, medical instruments, specialist corrosion resistant products such as pipes. Stainless steel
pots and bans. Jewellery and watches.

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Non-ferrous metals do not contain iron . Some common non-ferrous metals are aluminium ,Duralumin ,
copper,zinc,brass ,gilding metal and tin . Consequently, they do not to rust or suffer unduly from contact
with moisture. They do not react to a magnet.
Aluminium:
Light grey in colour. Smelted from bauxite ore. Aluminium 95%, Copper 4%, Manganese 1%
Ductile, soft, malleable, machines well on lathes and milling machines. Very light and resists
corrosion. Can be cast into products from ingots.…read more

Comments

MarsdenAlice

Short but to the point. Good resource for revision rather than learning for the first time.

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