CWS Welding Processes & Techniques — Questions and Answers
Question 1: After a hermetically sealed can is opened, which SMAW electrode must be kept in a heated holding oven to control moisture pickup?
- E6010
- E6013
- E7018 (Correct answer)
- E7024
Correct answer: E7018
E7018 is a low-hydrogen electrode whose coating absorbs moisture, so it must be stored in a holding oven (typically about 250°F minimum) to prevent hydrogen cracking.
Question 2: Which GMAW metal transfer mode has the lowest heat input and is best suited for thin sheet and out-of-position welding?
- Axial spray transfer
- Globular transfer
- Short-circuiting transfer (Correct answer)
- Rotational spray transfer
Correct answer: Short-circuiting transfer
In short-circuiting transfer the wire touches the weld pool many times per second at low voltage and current, giving low heat input.
Question 3: A field crew must weld structural steel outdoors in windy conditions with no wind screens. Which process is most suitable?
- GMAW with argon/CO2
- GTAW
- Self-shielded FCAW (FCAW-S) (Correct answer)
- Gas-shielded FCAW (FCAW-G)
Correct answer: Self-shielded FCAW (FCAW-S)
FCAW-S makes its own shielding from the core ingredients, so wind does not blow away an external shielding gas.
Question 4: In GTAW with direct current electrode negative (DCEN), roughly how much of the arc heat goes into the workpiece?
- About one-third
- About one-half
- About two-thirds (Correct answer)
- Almost none
Correct answer: About two-thirds
With DCEN about two-thirds (roughly 70%) of the heat goes into the work, which gives deep penetration and keeps the tungsten cool.
Question 5: Which arc welding process is normally limited to the flat and horizontal fillet positions because of its granular flux blanket?
- Submerged arc welding (Correct answer)
- Flux cored arc welding
- Shielded metal arc welding
- Plasma arc welding
Correct answer: Submerged arc welding
SAW uses loose granular flux that must lie over the joint, so it is generally restricted to flat and horizontal positions.
Question 6: Which condition is needed to get axial spray transfer in GMAW of carbon steel?
- 100% CO2 shielding at low current
- Argon-rich shielding gas and current above the transition current (Correct answer)
- Helium shielding with DCEN polarity
- Any shielding gas with voltage below 18 V
Correct answer: Argon-rich shielding gas and current above the transition current
Spray transfer needs an argon-rich gas (usually at least about 80% Ar) and a current above the transition current for that wire size.
Question 7: Electroslag welding is mainly used for which application?
- Thin-gauge sheet metal in the flat position
- Thick plates welded vertically in a single pass (Correct answer)
- Root passes on small-diameter pipe
- Overhead fillet welds on light structures
Correct answer: Thick plates welded vertically in a single pass
ESW welds very thick sections in the vertical position in a single pass, but its high heat input can coarsen the HAZ grain.
Question 8: An SMAW welder using DC sees the arc wander at the end of a joint because of arc blow. What is the most effective corrective action?
- Increase the welding current
- Switch to an AC power source (Correct answer)
- Use a longer arc length
- Move the work lead next to the arc
Correct answer: Switch to an AC power source
Arc blow comes from magnetic fields around DC current; AC reverses constantly and largely removes the effect.
Question 9: In plasma arc welding, what does the keyhole technique do?
- It removes the need for shielding gas
- It lets the arc fully penetrate the joint, and the molten metal flows behind it (Correct answer)
- It lets the weld be deposited only as surface cladding
- It means a consumable tungsten electrode is used
Correct answer: It lets the arc fully penetrate the joint, and the molten metal flows behind it
In keyhole PAW the constricted arc pierces the joint thickness and molten metal closes behind it, giving complete penetration in a single pass.
Question 10: Which oxyacetylene flame is normally used to weld carbon steel?
- Oxidizing flame
- Carburizing flame
- Neutral flame (Correct answer)
- Reducing flame with excess oxygen
Correct answer: Neutral flame
A neutral flame has roughly equal oxygen and acetylene, so it neither adds carbon to the steel nor oxidizes it.
Question 11: What DC polarity is normally recommended for air carbon arc cutting (CAC-A) with standard DC copper-coated electrodes?
- DCEN
- DCEP (Correct answer)
- AC only
- Either polarity gives the same results
Correct answer: DCEP
Standard DC copper-coated carbon electrodes are used on DCEP for a stable arc and efficient metal removal.
Question 12: An inspector reports undercut along the toes of fillet welds. What is the most likely cause?
- Welding current too low
- Excessive current or travel speed (Correct answer)
- Insufficient preheat
- Electrode diameter too small for the joint
Correct answer: Excessive current or travel speed
Too much current, travel speed, or arc length melts the base metal at the toe without enough filler to fill the groove.
Question 13: In GMAW, how does a push (forehand) torch angle compare with a drag (backhand) angle?
- Deeper penetration and a narrower, higher bead
- Shallower penetration and a flatter, wider bead (Correct answer)
- More spatter and deeper penetration
- No difference in bead shape
Correct answer: Shallower penetration and a flatter, wider bead
Pushing aims the arc ahead onto cold metal, which gives a wider, flatter bead with less penetration than dragging.
Question 14: A welder using a constant-voltage GMAW machine increases the contact-tip-to-work distance (stickout). What happens to the welding current?
- It increases
- It decreases (Correct answer)
- It stays exactly the same
- It reverses polarity
Correct answer: It decreases
Longer stickout adds resistance heating in the wire, so a CV power source supplies less current.
Question 15: What type of power source output is normally used for shielded metal arc welding?
- Constant voltage (flat)
- Constant current (drooping) (Correct answer)
- Constant power only
- Pulsed constant voltage
Correct answer: Constant current (drooping)
SMAW uses a constant-current (drooping) power source so the current stays steady as the welder's arc length changes.
Question 16: Why is E6010 often chosen for open-root passes on pipe?
- It has a low-hydrogen, iron-powder coating
- Its high-cellulose sodium coating gives a forceful arc and deep penetration (Correct answer)
- It runs only on AC with a soft arc
- It gives a heavy slag that is best for flat-position cover passes
Correct answer: Its high-cellulose sodium coating gives a forceful arc and deep penetration
The cellulosic coating of E6010 gives a digging arc with deep penetration and a light slag, which suits root passes in all positions.
Question 17: In arc stud welding, what is the ceramic ferrule for?
- It supplies the filler metal
- It concentrates heat, shields the molten metal, and shapes the weld (Correct answer)
- It insulates the stud from the welding current
- It acts as a permanent part of the finished joint
Correct answer: It concentrates heat, shields the molten metal, and shapes the weld
The ferrule keeps in the arc heat, shields the molten pool, and forms the weld fillet, and it is broken off after welding.
Question 18: What are the three primary variables in resistance spot welding?
- Voltage, travel speed, and gas flow
- Current, weld time, and electrode force (Correct answer)
- Wire feed speed, stickout, and voltage
- Preheat, interpass temperature, and PWHT
Correct answer: Current, weld time, and electrode force
Spot weld heat follows I²Rt, so current, time, and electrode force (which affects contact resistance) are the key variables.
Question 19: Why do WPSs for quenched and tempered steels often set a maximum interpass temperature?
- To raise deposition rate
- To prevent HAZ softening and loss of toughness from too much heat input (Correct answer)
- To stop the flux from melting
- To lower the needed preheat
Correct answer: To prevent HAZ softening and loss of toughness from too much heat input
Too much heat can over-temper Q&T steels, which lowers HAZ strength and toughness, so heat input and interpass temperature are limited.
Question 20: What is a main advantage of pulsed GMAW over conventional spray transfer?
- It needs no shielding gas
- It gives spray-type transfer at a lower average current, so out-of-position welding is possible (Correct answer)
- It only works with 100% CO2
- It removes the need to clean the joint
Correct answer: It gives spray-type transfer at a lower average current, so out-of-position welding is possible
Pulsing switches between a peak and a background current, giving spray-like droplet transfer at lower average heat input.
Question 21: When welding aluminum with AC GTAW, during which part of the cycle does oxide cleaning happen?
- The electrode-negative half cycle
- The electrode-positive half cycle (Correct answer)
- Only during arc starting
- Only during crater fill
Correct answer: The electrode-positive half cycle
During the electrode-positive half cycle, positive ions strike the work and break up the aluminum oxide layer (cathodic cleaning).
