CWS CWS Metallurgy & Material Properties

Question 1

Which alloying element in steel has the greatest effect on hardenability and is the primary contributor to the carbon equivalent (CE) formula?

Accepted Answer

Carbon

Answer

Carbon has the greatest individual effect on hardenability and is the primary element in the carbon equivalent formula used to assess weldability.

Question 2

What microstructural transformation occurs in steel when it is heated above the upper critical temperature (Ac3) and then rapidly quenched?

Accepted Answer

Martensite formation

Answer

Rapid quenching from above Ac3 traps carbon in the iron lattice, forming hard, brittle martensite — a body-centered tetragonal structure.

Question 3

A CWS supervisor is welding ASTM A514 (T-1) high-strength steel. What is the primary welding concern with this material?

Accepted Answer

Hydrogen-induced cold cracking

Answer

A514 high-strength, low-alloy quenched and tempered steel has high hardenability and is highly susceptible to hydrogen-induced cold cracking (HICC) in the HAZ.

Question 4

What does the term 'sensitization' refer to in austenitic stainless steel?

Accepted Answer

Chromium carbide precipitation at grain boundaries causing intergranular corrosion

Answer

Sensitization occurs when austenitic stainless steel is heated between 800–1500°F, causing chromium carbides to form at grain boundaries and depleting chromium from adjacent zones.

Question 5

Which heat treatment process is used to refine grain size and relieve internal stresses in carbon steel after welding?

Accepted Answer

Normalizing

Answer

Normalizing heats steel above Ac3, holds it, then air-cools to refine grain structure and relieve stresses induced by welding or forming.

CWS - Certified Welding Supervisor Practice Test

CWS - Certified Welding Supervisor Practice Test

CWS CWS Metallurgy & Material Properties