Welding Glossary I

Term	Definition
I.D.	Inside diameter, the interior size of a pipe or tube, measured at its widest point.
Icicles	An undesirable condition where excess weld metal protrudes beyond the root of the weld.
Ignition temperature	The temperature at which a material will burn if enough oxygen is present.
Impact strength	The ability of a material to withstand impact or hammering forces without cracking or breaking.
Impact test	A test that carefully measures how materials behave under heavy loading, such as bending, tension, or torsion.Charpy or Izod tests, for example, measure energy absorbed when breaking a specimen.
Impurities	Undesirable elements or compounds in a material.
Inch switch	A switch on a welding machine that is used to slowly feed consumable wire through a combination cable to a TIG (GTAW) torch.
Incomplete fusion	Failure of weld metal to fuse completely with the base metal or the preceding bead.
Inclusion	A gas bubble or nonmetallic particle entrapped in the weld metal as a result of improper arc heat or filler material manipulation.
Inert gas	A gas which does not normally combine chemically with the base metal or filler metal.
Indentation	A depression left on the surface of base metal after a spot, seam, or projection weld is made.
Indenter	In a hardness test, the ball or diamond that is pressed into the surface being tested.
Inductance	In the presence of a varying current in a circuit, the magnetic field surrounding the conductor generates an electromagnetic force in the circuit itself.If a second circuit is adjacent to the first, the changing magnetic field will cause (induce) voltage in the second circuit.An application of this principle is the step-down transformer used in welding machines.
Infrared rays	Heat rays which come from the welding arc.
Inert gases	Shielding gases, such as argon, helium, that do not react with the weld.
Inorganic	Being or composed of material that was never living; mineral, as compared to plant or animal.
Inorganic fluxes	Welding fluxes that do not contain carbon.They are very corrosive, so they are not used on electrical or electronic parts.
Input power	Electrical power required to operate a given welding machine.
Inside corner weld	Two metals fused together; one metal is held 90 degrees to the other.The fusion is performed inside the vertex of the angle.
Inspection	The process of examining welds for suitable, without damaging or destroying them.
Insulation	A material that will not permit the flow of electricity, used as a covering on wires, cables, and electrode holders.
Intermittent weld	Joining two pieces and leaving un-welded sections or gaps in the joint.
Interpass heating	Heating or reheating a joint between the passes needed to complete the weld.
Inverter	Power source which increases the frequency of the incoming primary power source.