Base Metal Preparation Flashcards
7 cards from real Certified Welder practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Base Metal Preparation flashcards as text
Which NDT method is most effective for detecting surface cracks in the heat-affected zone of prepared carbon steel joints before welding?
Answer: Magnetic particle testing (MT)
Magnetic particle testing reveals surface and near-surface discontinuities such as laminations and cracks on carbon steel, making it ideal for pre-weld inspection.
When preparing a joint for welding on galvanized steel, the zinc coating must be removed from the weld zone primarily because:
Answer: Zinc fumes are toxic and zinc causes porosity and cracking
Zinc vaporizes at welding temperatures producing toxic zinc oxide fumes and leaves voids in the weld metal, causing porosity and potential metal fume fever.
What does the term 'back gouging' refer to in weld joint preparation?
Answer: Removing the root of the first-side weld to sound metal before welding the second side
Back gouging removes any incomplete fusion, cracks, or inclusions from the root side of the first weld pass to ensure full fusion when the second side is welded.
A carbon equivalent (CE) value above 0.45 for a steel base metal indicates:
Answer: Increased hardenability and susceptibility to hydrogen cracking — preheat required
Carbon equivalent values above 0.45 indicate high hardenability; rapid cooling after welding can form martensite in the HAZ, making preheat essential to prevent cracking.
When using plasma arc cutting to prepare stainless steel joint edges, the cut surface must be dressed before welding to remove:
Answer: The dross, heat-affected zone, and hardened edge layer
Plasma cut edges on stainless steel have dross, heat-discolored oxide layers, and a narrow hardened zone that can cause porosity and cracking if not removed.
What is the correct sequence for joint preparation on contaminated carbon steel plate?
Answer: Degrease → grind/clean → dry → inspect → fit-up
Degreasing first prevents grinding from spreading oils deeper into the surface; cleaning and drying follow before inspection and fit-up to the weld specification.
Which groove design requires the least filler metal and produces the least distortion for a butt joint in plate thicker than 1 inch?
Answer: Double-V groove
The double-V groove splits the weld volume between both sides, reducing total filler metal needed and balancing shrinkage forces to minimize angular distortion.