Weld Discontinuities and Defects Flashcards
7 cards from real CWI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Weld Discontinuities and Defects flashcards as text
A weld inspector observes that a weld bead has a very rough, irregular surface profile. Which process parameter is the MOST likely cause?
Answer: Incorrect polarity
Incorrect polarity in SMAW or GMAW can cause irregular, rough bead profiles as the arc characteristics become unstable and transfer changes.
What is 'burn-through' in welding and when does it most commonly occur?
Answer: A hole melted completely through the base metal, common in thin sections
Burn-through is a hole melted completely through the base metal or weld, most commonly occurring when welding thin materials with excessive heat input.
Which test method can directly measure the depth of undercut in a production weld?
Answer: Undercut gauge (fillet weld gauge)
An undercut gauge is a mechanical depth gauge used by welding inspectors to measure the actual depth of undercut at the weld toe.
Stress corrosion cracking (SCC) in welds is promoted by which combination of conditions?
Answer: Tensile stress, susceptible material, and corrosive environment
SCC requires three simultaneous conditions: tensile residual or applied stress, a susceptible alloy microstructure, and a specific corrosive environment.
In radiographic testing, a weld discontinuity that appears as an irregular dark area with no defined boundaries most likely indicates:
Answer: Slag inclusion
Slag inclusions typically appear as irregular dark areas with jagged or diffuse boundaries on radiographs, while porosity appears as rounded dark spots.
Which welding defect is described as 'cold lap' and how does it differ from overlap?
Answer: Cold lap = fusion discontinuity at the weld interface; overlap = weld metal flowing onto base metal without fusion
Cold lap refers to a fusion discontinuity between weld passes or between weld and base metal, while overlap specifically refers to weld metal protruding beyond the weld toe without fusion.
A CWI finds cracks at the HAZ of a high-strength low-alloy (HSLA) steel weld, appearing 24–72 hours after welding. This is MOST likely:
Answer: Hydrogen-induced cold cracking (HICC)
Hydrogen-induced cold cracking (HICC) typically appears hours to days after welding in the HAZ of hardenable steels when hydrogen, stress, and susceptible microstructure coincide.