METALS

METALS

1. The main types of metal

   • Iron, copper, silver, tin, gold and lead
     • The most important alloys
       • Bronze, brass, steel and stainless steel

2. The general properties of metals

   • Metals are very dense. They are good heat and electricity conductors. They reflect light. All metals, except mercury, are solid at room temperature. Most metals are a grey or whitish colour. They can be mixed with other metals and substances to improve their properties.
     • Some of the technological properties are: Castability, weldability, ductility, malleability, foldability and machinability.

3. Obtaining metals

   • Mining and metallurgy
     • Open-pit mines
     • Underground mines
     • The environmental impact of extracting metals
       • Mining spoils the landscape. It alters the soil structure. Blasting produces dust and smoke pollution. Sound pollution and some are toxic.

4. Ferrous metals

   • Pure Iron, steel and cast iron.
     • Blast furnaces: Iron or iron ore. Fuel. Flux.
     • Steel: 1.Eliminating impurities. 2.Mixed with coal and limestone. 3.Pig iron. 4.Refining.
     • Steel alloys. Steel can be mixed with: Silicon (metalloid), manganese, nickel, tungsten, chromium, molybdenum, titanium, vanadium, niobium and lead.

5. Non-ferrous metals

   • Metals used in industry
     • Magnesium, aluminium, titanium, vanadium, chromium, manganese, cobalt, nickel, copper, zinc, molybdenum, tin, tugsten, mercury and lead.
   • No-ferrous alloys used in industry
     • Cooper: Bronze, brass, copper-nickel, aluminium bronze and nickel silver. Aluminium: Duralumin and zinc-aluminium.

6. Metalworking tools

   • Drilling tools: Drills, drill bits and punches.
   • Filing tools: Grinders or emery grinders, files and sandpaper.
   • Cutting tools: Hacksaw, snips, shears, jigsaw and angle grinder.
   • Joints
     • Permanent joints: Riveted joints, soldered joints and welding (oxyacetylene welding/electric arc welding).
     • Temporary joints: Screws and nuts.
   • Other types of metalwork
     • Forging. Milling. Turning. Wire drawing. Rolling. Stamping. Die cutting.