Metal

• What are the two main groups into which metals are divided?

  Ferrous and non-ferrous metals
• What characterizes ferrous metals?


  They contain iron and are normally magnetic
• What defines non-ferrous metals?


  They contain no iron and are normally non-magnetic
• What is an alloy?


  A combination of two or more metals
• What is the life cycle of metals?


  • Ore is dug from the ground
  • Transported for conversion to metal
  • Manufactured into products
  • Sent to retailers
  • Sold to users
  • Disposed of by melting down or landfill
• What are the environmental consequences of mining and processing metals?


  It uses a lot of energy, emits fumes, and damages the earth when left in landfills
• What is the chemical symbol for iron?


  Fe
• From what ores is iron made?


  Iron is made from iron ores called Magnetite or Haematite
• How is iron converted into steel?


  By introducing small percentages of carbon into its structure during manufacture
• How does the amount of carbon added to iron affect the steel produced?


  It determines the types of steel produced and their differing properties
• What are some benefits of alloying metals?


  Change in melting point, increased strength, and enhanced resistance to corrosion
• What are the properties of aluminium?


  • Soft, durable, lightweight
  • Ductile and malleable
  • Good conductor of heat and electricity
  • Difficult to join
• How does the density and stiffness of aluminium compare to steel?


  Aluminium has about one-third the density and stiffness of steel
• Why is aluminium almost always alloyed?


  To markedly improve its mechanical properties, especially when tempered
• What are some common uses of aluminium?


  • Kitchen foil
  • Cooking pans
  • Window frames
  • Ladders
• What are the properties of copper?


  Malleable, ductile, tough, and a good conductor of heat and electricity
• What is the composition of brass?


  Copper 65% and Zinc 35%
• What are the properties of brass?


  Heavy, quite hard, gold in color, easily machined, and joined by soldering
• What is the primary use of zinc?


  Galvanizing products to protect them from rusting
• What are the properties of mild steel?


  Tough, ductile, malleable, and poor resistance to corrosion
• What is the composition of high carbon steel?


  Iron and 0.8%-1.5% carbon
• What are the properties of stainless steel?


  Hard, tough, and very good resistance to corrosion
• What is the composition of cast iron?


  Iron and 3.5% carbon
• What are the finishing processes for metals?


  • Natural barriers
  • Applied barriers
  • Finishes for metal
• What is the purpose of natural barriers on metals?


  To protect against environmental effects
• What is the process of 'blueing' steel?


  Heating steel up to 300 °C and then quenching in oil to form a protective oxide layer
• What are some applied barriers for protecting metals from corrosion?


  • Brushing
  • Rolling
  • Spraying
  • Dipping
• What are the types of finishes for metal?

  • Paint
  • Lacquer
  • Plastic dip coating
  • Oil bluing
  • Anodising
  • Electroplating
  • Galvanising
  • Enamelling
• What is the purpose of primer in painting metal?


  To ensure that the paint keys into the material's surface
• What is powder coating?


  A method of applying paints using a dry powder that is statically charged
• What is the process of electroplating?


  An electrochemical process that allows ions from the coating material to form on the base material
• What is anodising in relation to aluminium?


  A process that makes the surface of aluminium more durable and resistant to scratches
• What are the steps in the enamelling process?

  1. Clean metal in degreaser bath
  2. Etch in acid bath
  3. Rinse and neutralize
  4. Apply ground coat and fire
  5. Apply cover coat and fire
  6. Repeat for additional colors
• What is the purpose of lacquering metal?


  To prevent superficial oxidation and loss of finish or color
• What are common forms in which metal is available?

  • Rod
  • Square
  • Flat
  • Hexagon
  • Sheet
  • Round Tube
  • Square Tube
• What is the diameter range for rods of metal?


  5 - 50 mm
• What is the thickness range for flat metal?


  From 1.5 - 6 mm thick
• What is the diameter range for round tubes of metal?


  5 - 40 mm
• What is the square size range for square tubes of metal?


  12 - 25 mm square