456A SMAW (Shielded Metal Arc Welding) 2

Question 1

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

Accepted Answer

Provides shielding gas and slag to protect the weld pool, stabilizes the arc, and adds alloying elements

Answer

The flux coating on a SMAW electrode serves multiple functions: it generates shielding gases (CO2, CO) to protect the molten pool from atmospheric contamination, forms slag to protect the solidifying weld, stabilizes the arc, and can introduce alloying elements into the weld metal.

Question 2

When welding with E7018 electrodes, what defect is most likely if the electrodes have absorbed moisture?

Accepted Answer

Hydrogen-induced cracking (underbead cracking)

Answer

Moisture in low-hydrogen electrodes decomposes in the arc and introduces hydrogen into the weld metal. This hydrogen can diffuse to stress concentration points and cause hydrogen-induced cracking (HIC), also known as cold cracking or underbead cracking.

Question 3

What is the correct technique for striking an arc with a SMAW electrode?

Accepted Answer

Scratch or tap the electrode on the base metal and quickly establish the correct arc length

Answer

The scratch or tap method is used to initiate the SMAW arc. The electrode is moved across the base metal like striking a match (scratch) or briefly touched and lifted (tap). The arc length should be established quickly to prevent electrode sticking.

Question 4

What does arc blow refer to in SMAW welding?

Accepted Answer

Deflection of the arc from its intended path due to magnetic fields

Answer

Arc blow is the deflection of the welding arc caused by magnetic fields in the workpiece. It is most common when welding DC on ferromagnetic materials near the ends of joints or in corners. It can cause poor fusion and uneven bead profiles.

Question 5

Which of the following is a remedy for arc blow during SMAW?

Accepted Answer

Switch from DC to AC current

Answer

Switching from DC to AC eliminates arc blow because AC current alternates direction, preventing the buildup of a sustained magnetic field in the workpiece. Other remedies include repositioning the work lead, angling the electrode, or welding toward the work lead.

Red Seal Welder 456A Practice Test

Red Seal Welder 456A Practice Test

456A SMAW (Shielded Metal Arc Welding) 2