ITMC Welding Fundamentals 2

Question 1

Which welding defect is characterized by incomplete fusion between the weld metal and the base metal along the weld toe?

Accepted Answer

Lack of fusion

Answer

Lack of fusion occurs when the weld metal fails to completely bond with the base metal or previous weld pass at the fusion zone.

Question 2

In GMAW (MIG welding), what is the function of the shielding gas?

Accepted Answer

To protect the weld pool from atmospheric contamination

Answer

Shielding gas in GMAW surrounds the arc and molten weld pool to prevent oxygen, nitrogen, and hydrogen from contaminating the weld.

Question 3

What does the term 'duty cycle' refer to in welding equipment?

Accepted Answer

The percentage of a 10-minute period a welder can operate at rated output

Answer

Duty cycle is the percentage of a 10-minute period that a welding machine can operate at its rated amperage without overheating.

Question 4

Which electrode classification is used for low-hydrogen SMAW electrodes?

Accepted Answer

EXX18

Answer

Electrodes ending in 8 (such as E7018) have a low-hydrogen iron powder coating that minimizes moisture and hydrogen in the weld.

Question 5

What causes spatter in GMAW welding?

Accepted Answer

Voltage too high or wire feed speed too low relative to voltage

Answer

Spatter in GMAW is commonly caused by an imbalance between voltage and wire feed speed, producing an unstable arc that expels molten droplets.

(ITMC) Industrial Technology Maintenance Certification Practice Test