lesson 2

• Ferrous metals


  Any metal that contains iron
• Ferrous metals


  • Favored for their tensile strength and durability
  • Often utilized in housing construction, large-scale piping and industrial containers
• Non-ferrous metals


  Metals that don't contain iron
• Non-ferrous metals


  • Much more malleable and lighter than ferrous metals
  • Particularly suited for use where strength is required but weight needs to be considered, such as in the aircraft industry
• Types of metals


  • Ferrous metals
  • Non-ferrous metals
• Pure metal


  An element (e.g. iron, copper, gold)
• Alloy


  A mixture of two or more elements (e.g. iron and carbon = steel, brass = copper + zinc)
• Examples of ferrous metals

  • Steel
  • Cast iron
  • Wrought iron
• Ferrous metals


  • Have magnetic properties
  • Prone to rusting (except stainless steel and wrought iron)
  • Used in construction, fencing, manufacturing, bridges, machines tool parts
• Steel


  A combination of iron and carbon, renowned for its strength and machinability
• Market forms of steel

  • Angle sections
  • Channel sections
  • Corrugated sheets
  • Expanded Metal
  • Flat Bars
  • I-sections
  • Plates
  • Round bars
  • Square bars
  • T-Sections
  • Ribbed-tor steel bars
• Stainless steel


  An alloy steel made with the addition of chromium to steel, which provides resistance against rust
• Carbon steel


  Contains a high carbon content that is added to iron to create an exceptionally hard metal that is used for tools
• Cast iron


  A hard and wear resistant metal that is widely used for items including cookware, machine tools, engines, manhole covers and water pipes
• Wrought iron


  Unlike most other ferrous metals, wrought iron is able to resist corrosion and oxidation. It is typically used for fences, railings and gates
• Corrosion


  The process in which oxidation caused by chemical or electrochemical reactions causes a material to deteriorate
• Rust


  The oxidation of iron that has been exposed to air and moisture. Rust is a type of corrosion, but not all corrosion is rust
• Causes of corrosion (especially to reinforcing bars in concrete)

  • Congested reinforcement in small concrete section
  • Excessive water-cement ratio
  • Improper construction methods
  • Inadequate design procedure
  • Initially rusted reinforcement before placing concrete
  • Insufficient cover to steel from the exposed concrete surfaces
  • Permeability of concrete which depends on various factors such as water-cement ratio, size of aggregate, curing, grading of aggregates, etc.
  • Presence of moisture in concrete
  • Presence of salts
• Non-ferrous metals


  Includes aluminum, copper, lead, zinc and tin, silver, and gold
• Non-ferrous metals


  • Their main advantage is their malleability, no iron content giving them higher resistance to rust and corrosion
  • Ideal for gutters, liquid pipes, roofing and outdoor signs
  • Non-magnetic, for electronic and wiring applications
  • Used in Aircraft Frames, Automotive Applications, Appliances, Marine Technology, Hydro Power, Electrical Wiring, etc.
• Copper


  • Red in color, highly ductile, malleable and has high conductivity for electricity and heat
  • Principally used in the electric industry
• Lead


  • Soft, heavy, malleable metal with a low melting point and low tensile strength
  • Can withstand corrosion from moisture and many acids
  • Used in electrical power cables, batteries, building construction and soldering
• Zinc


  • Medium to low strength metal with a very low melting point
  • Used in galvanizing (the process of applying a protective zinc coating to iron or steel to prevent rust)
• Tin


  • Very soft, and malleable, ductile with low tensile strength
  • Often used to coat steel to prevent corrosion (e.g. Tin cans, tin foil in 19th Century)
• Properties of aluminum


  • Lightweight
  • Corrosion Resistant
  • Electrical and thermal conductivity
  • Ductility
  • Strength at low temperature
  • Impermeable and odorless
  • Non-magnetic
  • Non-toxic
  • Sound and shock absorbent
  • Non-sparking
  • Recyclability
• Uses of aluminum in houses


  • Exterior: Window frames, Doors, Sliding doors, Green houses
  • Interior: Partition, Door handles, Locker, Furniture, Book shelf
  • In Buildings: Roofing, Curtain walls, Solar panels, Shades, Bridges, Domes