Definitions and Terminology
Definitions and Terminology is a vocabulary domain, but the exam does not ask for dictionary definitions. It gives a scenario and expects the right term, or it tests two terms that get confused on the floor every week.
Joints, welds, positions
- Joint types: butt, lap, T, corner, edge.
- Weld types: groove, fillet, plug, slot, spot, seam, surfacing, plus tack and stitch patterns common in robotic work.
- Positions: 1G flat groove, 2G horizontal, 3G vertical, 4G overhead; 1F through 4F for fillets; 6G for pipe at 45 degrees. The letter tells you groove or fillet, the number tells you position.
Documents and variables
- The WPS is the instruction production works from. The PQR is the record of the test that proved the procedure; it supports the WPS but never replaces it.
- Essential variables require requalification when changed: process, filler classification, position, preheat, polarity, and in many codes heat input range.
- Nonessential variables may be changed within stated limits by the manufacturer.
- Procedure qualification proves the procedure; performance qualification proves the welder or welding operator.
Productivity and process terms
- Duty cycle is the percentage of a ten minute period a power source can run at rated output.
- Arc-on time, or operator factor, is the fraction of paid time the arc is actually burning.
- Deposition efficiency is deposited metal divided by consumed wire; it drops with spatter and with long stickout.
- A discontinuity is any interruption in the weld; a defect is a discontinuity that exceeds acceptance criteria. Not every discontinuity is a defect.
Worked example
A qualified WPS lists 0.045 in ER70S-6, 90Ar/10CO2 at 35 cfh, 26 V, 210 A, and a heat input maximum of 40 kJ/in. Production switches to 0.035 in wire to reduce spatter and keeps the same voltage. Filler classification and size are essential variables for GMAW procedure qualification in structural work, so this is not a nonessential tweak: it requires requalification or a documented revision supported by new test data. Voltage also shifts because the smaller wire needs a different arc characteristic.