CWI Metallurgy and Weld Discontinuities 3

Question 1

Which element is most commonly responsible for increasing hardenability in low-alloy steels?

Accepted Answer

Manganese

Answer

Manganese is the most effective common alloying element for increasing hardenability, allowing martensite to form at slower cooling rates.

Question 2

What type of discontinuity results from entrapped non-metallic material (such as flux) within a completed weld?

Accepted Answer

Slag inclusion

Answer

Slag inclusions are non-metallic solid materials entrapped in weld metal or between weld metal and base metal, often caused by improper inter-pass cleaning.

Question 3

Hydrogen-induced cracking (HIC) in welds is also commonly known as:

Accepted Answer

Cold cracking

Answer

Hydrogen-induced cracking is called cold cracking because it occurs at or near room temperature after welding is complete, unlike hot cracks which form during solidification.

Question 4

The carbon equivalent (CE) formula is used by CWI inspectors primarily to assess:

Accepted Answer

Risk of hydrogen-induced cracking (cold cracking)

Answer

The carbon equivalent formula estimates a steel's susceptibility to hydrogen-induced cold cracking by accounting for the hardenability effect of alloying elements.

Question 5

Which weld discontinuity is described as a depression or groove in the weld face that goes below the surface of the adjacent base metal?

Accepted Answer

Underfill

Answer

Underfill is a condition where the weld face or root surface is below the adjacent base metal surface due to insufficient weld metal deposition.

CWI Practice Test

CWI Practice Test

CWI Metallurgy and Weld Discontinuities 3