Shielded Metal Arc Welding (SMAW) Flashcards

What is the primary purpose of the flux coating on a SMAW electrode?

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.

When welding in the vertical-up position with an E7018 electrode, what technique is most commonly recommended?

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.

Which of the following electrodes is classified as a low-hydrogen electrode?

Answer: E7018

The E7018 is a low-hydrogen electrode, indicated by the '8' suffix which denotes a low-hydrogen potassium iron powder coating.

What condition is most likely indicated by a hissing or sputtering arc during SMAW?

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.

What is the minimum storage temperature required for low-hydrogen electrodes (E7018) after they have been removed from their original hermetically sealed container?

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.

In SMAW, what does the term 'undercut' refer to?

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.

Which factor most directly affects the deposition rate in SMAW?

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.