btech metals etc.

• elementary substances which are crystalline when solid, characterized by opacity, ductility, conductivity, and luster

  Metals
• a metal having iron as base metal

  ferrous metals
• wrought iron was used for sculptures and weapons

  1000 B.C.
• invention of coke (coal-cake)


  1700's
• wrought iron was further developed by

  Henry Cort
• enumerate the types of ferrous metal

  • cast iron
  • wrought iron
  • steel
• hard, brittle, non malleable iron based alloy with carbon, 2.0% to 4.5%, and silicon, casted in sand mold and machine

  cast iron
• a tough , malleable, relatively soft iron that is readily forged and welded, having a fibrous structure containing approximately 0.2% carbon and small amount of uniformly distributed slag

  wrought iron
• iron-based alloys having a carbon content less than that of cast iron and more than that of wrought iron

  steel
• cast iron annealed by transforming the carbon content into graphite or removing it completely

  malleable cast iron
• enumerate 6 advantages of metals

  • sturdy and rigid
  • durable
  • recyclable material
  • time saving
  • high strength to weight ratio
  • versatile
• enumerate 5 disadvantages of metals

  • low tolerance to heat which requires fire proofing
  • high production cost
  • deteriorates by oxidation
  • heavy (7850 kg/m^3)
  • high thermal expansion
• production of steel


  label

  
• crude iron that is drawn from the blast furnace and cast into pigs in preparation for conversion into cast iron, wrought or steel

  pig iron
• mass of metal cast into convenient shape for storage or transportation before further processing

  ingot
• round or square, more than 230cm63 in cross sectional area (congruent to 15cm x 15 cm)

  blooms
• round or square, less than 230 cm^3 in cross sectional area

  billets
• 2 types of steel working methods

  • hot-working
  • cold-working
• metal working at a temperature high enough to permit the metal to recrystallize to acquire a new granular structure with crystals because of plastic deformation


  hot-working
• metal working below the temperature at which recrystallization occur

  cold-working
• roll metal at high temperature; with dark, oxidized, and relatively rough finish


  hot-rolled
• pouring molten metal into a form

  casting
• forcing molten metal into a metallic mold under hydraulic pressure

  die casting
• form metal by heating and hammering

  forge
• roll metal at a temperature below recrystallization; increases tensile strength or improve surface finish

  cold-rolled
• forming a metal with a desired cross section by forcing it through a die with pressure ram

  extrusion
• metal drawn through a set of dies to reduce its cross sectional area without pre-heating


  cold-drawn
• process by which formed or worked metals are treated for additional strength or for corrosion resistance

  after production treatment
• methods of treating metals

  • heat treatment
  • cladding/plating
• types of heat treatment

  -annealed

  • quench
  • tempered
  • case-hardening
• controlled heating and cooling of a metal to develop desired physical and mechanical properties

  heat treatment
• heating below recrystallization and gradually cooled; removes internal stresses and adds ductility to the metal

  annealed
• rapid cooling or the immersion to water of a heated metal; increases hardness

  quench
• reheating at a lower temperature and slow cooling of the metal

  tempered
• outside surface hardened by carburization which unites iron to carbon; interior is tough and ductile

  case-hardening
• bonding one metal to another; usually used to protect the inner metal from corrosion

  cladding/plating
• gradual deterioration of metal, by chemical reaction, when exposed to weather, moisture, or other corroding agents

  corrosion
• methods of cladding metals

  -electroplating

  • dipped/dipping
• types of steel

  • carbon steel
  • alloy steel
• types of carbon steel and its carbon content

  • mild steel or soft steel (0.15% to 0.25%)
  • medium steel (0.25% to 0.45%)
  • hard steel (0.45% to 0.85%)
  • spring steel (0.85 to 1.80%)