AWS AWS Metallurgy & Materials 2

Question 1

What is the purpose of Post-Weld Heat Treatment (PWHT)?

Accepted Answer

To relieve residual stresses and temper hard microstructures

Answer

PWHT reduces residual stresses, improves toughness, and tempers hardened zones in the weld and HAZ.

Question 2

Which test is commonly used to evaluate the toughness (notch impact energy) of a weld metal at low temperatures?

Accepted Answer

Charpy V-notch impact test

Answer

The Charpy V-notch impact test measures absorbed energy to assess toughness, especially at low temperatures.

Question 3

In welding metallurgy, what is 'sensitization' associated with in austenitic stainless steel?

Accepted Answer

Chromium carbide precipitation at grain boundaries, depleting chromium from the grain boundary region

Answer

Sensitization occurs when chromium carbides precipitate at grain boundaries, creating chromium-depleted zones susceptible to intergranular corrosion.

Question 4

What does the carbon equivalent (CE) formula help predict?

Accepted Answer

The susceptibility of steel to hydrogen-induced cracking

Answer

The carbon equivalent (CE) formula estimates a steel's hardenability and its susceptibility to hydrogen-induced cracking.

Question 5

Which microstructure in the HAZ of steel welds is most susceptible to hydrogen-assisted cracking?

Accepted Answer

Martensite

Answer

Martensite's high hardness and brittleness make it the microstructure most susceptible to hydrogen-assisted cracking.

AWS Practice Test