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Manual Metal Arc welding (MMA) – Engineering

1. Circuit

Step-down Transformer

Converts high voltage AC to a lower voltage (220V to 80V-100V). This means the
output current is greater than the input current. This is due to the primary coil having
more windings than the secondary coil.... (More)

Oxy-Acetylene welding – Engineering

  • Oxy-Acetylene is a Fusion welding process.
  • The joint edges are heated until the metals melt.
  • The molten metals join and fuse.
  • Oxidation is prevented by the envelope of products of combustion.

1. Acetylene

Acetylene would explode if directly compressed. Instead... (More)

Submerged Arc & Resistance Seam Welding – Engineering

Submerged Arc Welding

  • Uses bare wire electrode.
  • Fed automatically from spool.
  • Generates electric arc to heat metal/
  • Flux in powder form.
  • Fed using a hopper.
  • Electric arc melts joint, flux and electrode.
  • Excess flux is collected and re-used.
  • Fully automated... (More)

Iron Carbon Equilibrium Diagrams – Engineering Notes

Lower Critical Point

  • Occurs at 723°c.
  • Temperature change occurs.
  • The metal contracts dimensionally, glows less brightly and loses its magnetism.
  • Known as Decalescence.

Upper Critical Point

  • Varies depending on amount of carbon in the steel.
  • Above this point, the metal... (More)