ITMC Welding Fundamentals 3

Question 1

What is the primary purpose of preheating base metal before welding?

Accepted Answer

To reduce the risk of hydrogen cracking and thermal shock

Answer

Preheating slows the cooling rate of the weld, which reduces hydrogen-induced cracking and minimizes residual stresses caused by thermal gradients.

Question 2

In GTAW (TIG welding), what is the purpose of high-frequency (HF) arc start?

Accepted Answer

To initiate the arc without touching the tungsten to the workpiece

Answer

HF arc start allows the GTAW arc to be initiated without contaminating the tungsten electrode by touching the workpiece.

Question 3

Which symbol on a welding drawing indicates the weld is to be made all around the joint?

Accepted Answer

A circle at the junction of the arrow and reference line

Answer

A circle at the bend of the arrow on a welding symbol indicates that the weld is required all around the joint perimeter.

Question 4

What is the correct action when low-hydrogen electrodes (E7018) have been exposed to humidity?

Accepted Answer

Re-dry them in a rod oven per manufacturer specifications

Answer

Moisture-absorbed low-hydrogen electrodes must be re-dried in a rod oven at the manufacturer's recommended temperature and time to restore their low-hydrogen properties.

Question 5

What does PWHT (Post-Weld Heat Treatment) primarily accomplish?

Accepted Answer

Relieves residual stresses and improves toughness

Answer

PWHT reduces residual stresses locked in the weld and HAZ during cooling, and can improve toughness and resistance to stress corrosion cracking.

(ITMC) Industrial Technology Maintenance Certification Practice Test

(ITMC) Industrial Technology Maintenance Certification Practice Test

ITMC Welding Fundamentals 3