AWS Shielded Metal Arc Welding (SMAW) 4 — Questions and Answers
Question 1: What is the primary purpose of the flux coating on a SMAW electrode?
- To increase electrical conductivity
- To shield the weld pool from atmospheric contamination (Correct answer)
- To add carbon to the weld metal
- To reduce arc voltage
Correct answer: To shield the weld pool from atmospheric contamination
The flux coating decomposes during welding to produce shielding gases and slag that protect the molten weld pool from oxygen and nitrogen contamination.
Question 2: When welding in the vertical-up position with an E7018 electrode, what technique is most commonly recommended?
- Drag technique with fast travel speed
- Weave bead with slight pause at the toes (Correct answer)
- Backstep technique
- Circular motion with no pauses
Correct answer: Weave bead with slight pause at the toes
A weave bead with a slight pause at the toes helps control the molten pool and ensures proper fusion at the weld edges in vertical-up welding.
Question 3: Which of the following electrodes is classified as a low-hydrogen electrode?
- E6010
- E6011
- E6013
- E7018 (Correct answer)
Correct answer: E7018
The E7018 is a low-hydrogen electrode, indicated by the '8' suffix which denotes a low-hydrogen potassium iron powder coating.
Question 4: What condition is most likely indicated by a hissing or sputtering arc during SMAW?
- Correct arc length
- Arc length that is too short
- Arc length that is too long (Correct answer)
- Correct electrode angle
Correct answer: Arc length that is too long
A hissing or sputtering arc typically indicates the arc length is too long, causing instability and excessive spatter.
Question 5: What is the minimum storage temperature required for low-hydrogen electrodes (E7018) after they have been removed from their original hermetically sealed container?
- 50°F (10°C)
- 150°F (66°C) (Correct answer)
- 250°F (121°C)
- 500°F (260°C)
Correct answer: 150°F (66°C)
AWS D1.1 requires low-hydrogen electrodes to be stored at a minimum of 250°F (121°C) in a rod oven after opening, but held at 150°F (66°C) minimum in a holding oven.
Question 6: In SMAW, what does the term 'undercut' refer to?
- A groove melted into the base metal adjacent to the weld toe that is not filled (Correct answer)
- Incomplete fusion at the weld root
- Excess weld metal above the base metal surface
- A crack running along the center of the weld bead
Correct answer: A groove melted into the base metal adjacent to the weld toe that is not filled
Undercut is a groove melted into the base metal or previously deposited weld metal at the weld toe that remains unfilled, creating a stress concentration.
Question 7: Which factor most directly affects the deposition rate in SMAW?
- Base metal thickness
- Electrode diameter and amperage (Correct answer)
- Joint design
- Preheat temperature
Correct answer: Electrode diameter and amperage
Electrode diameter and amperage most directly control deposition rate, as larger electrodes at higher amperages deposit more weld metal per unit time.
AWS Shielded Metal Arc Welding (SMAW) 4
What is the primary purpose of the flux coating on a SMAW electrode?