NOCTI Study Guide
Uses extreme heat to join or fuse pieces of metal together.
The metal is heated to a softened state by electrodes. Pressure is applied and the metal is joined.
Pieces of metal are heated to the melting point, joined together, and allowed to cool.
The part of the joint where the wire electrode is directed.
The exposed surface of the weld on the side that has been welded.
Indicated by the height of the exposed surface of the weld on the back side. Full weld penetration is needed to assure maximum weld strength.
An indication of good weld penetration.
Results from penetrating too much into the
lower base metal, which burns a hole through the back side of the metal.
The width and height of the weld bead.
Refers to the depth of the triangular cross section of the weld.
Refers to holding work pieces tightly together, in alignment to prepare for welding.
Metal Inert Gas Welding (MIG)
Offers more advantages than other methods for welding high-strength steels and high-strength, low alloy steel component parts used in modern cars.
Tungsten Inert Gas (TIG)
Uses a handheld rod and gas-shielded arc, is often recommended when welding aluminum alloy body panels
Heat Effect Zone
The area around the weld that becomes adversely hot.
Thick covers made of fire-resistant cloth for protecting vehicle surfaces from heat, sparks, and weld splatter.
Needed when welding near on-board computers and sensor wiring.
DC Reverse Polarity
Means the wire (electrode) is positive and the workpiece is negative.
Welding Filter Lens
Sometimes called a filter plate, a shaded glass welding helmet insert for protecting your eyes from ultraviolet burns.
Affects the base metal penetration depth, the speed at which the wire is melted, arc stability, and the amount of weld splatter.
Producing a weld surface level lower than base metal.
Heat Sink Compound
A paste that can be applied to parts to absorb heat and prevent warpage.
Means the pieces are parallel with the bench or shop floor.
Has the pieces turned sideways.
Has the pieces turned upright.
Has the workpieces turned upside down.
A tack, relatively small, temporary MIG spot weld that is used instead of a clamp or sheet metal screw to tack and hold the fit in place while proceeding to make a permanent weld.
An uninterrupted seam or bead is laid down in a slow, steady, ongoing movement.
Made in a drilled or punched hole through the outside piece (or pieces).
In an MIG spot weld, the arc is directed to penetrate both pieces of metal, while triggering a timed impulse of wire feed.
In the MIG lap spot technique, the arc is directed to penetrate the bottom piece and the puddle is allowed to flow into the edge of the top piece.
A series of connecting or overlapping MIG spot welds, creating a continuous seam.
Backing strip, made of the same metal as the base metal can be placed behind the weld.
Aluminum Electrode Wire
Classified by series, according to the metal or metals the alluminum is alloyed with and whether the alluminum is heat treated.
A test piece of the same metal as the welded piece and with the same panel thickness.
To confirm a spot weld after it has been made, use a chisel and hammer and proceed.
The standard flame is said to be a neutral flame.
Also called a surplus or reduction flame, is obtained by mixing slightly more acetylene than oxygen.
Obtained by mixing slightly more oxygen than acetylene.
Also called thermal paint, can be used to determine the temperature of the alluminum or other metal being heated.
Applied only to places for sealing.
Plasma Arc Cutting
Creates an intensely hot air stream, which melts and removes metal over a very small area.