AWS Material Selection & Properties 2

Question 1

Which carbon content range classifies steel as 'high-carbon steel'?

Accepted Answer

0.60% to 1.00%

Answer

High-carbon steel contains approximately 0.60% to 1.00% carbon, making it harder but more brittle and difficult to weld.

Question 2

What does the term 'hardenability' refer to in welding metallurgy?

Accepted Answer

The ability of steel to form martensite upon rapid cooling

Answer

Hardenability describes how readily steel forms martensite through the depth of a section when quenched, which directly impacts weld HAZ properties.

Question 3

Which austenitic stainless steel grade is most susceptible to sensitization during welding?

Accepted Answer

304

Answer

Type 304 stainless steel is susceptible to sensitization because it lacks stabilizers or low carbon content to prevent chromium carbide precipitation.

Question 4

What is the primary purpose of adding niobium (columbium) to stainless steel?

Accepted Answer

Stabilize against intergranular corrosion during welding

Answer

Niobium acts as a stabilizer by preferentially combining with carbon, preventing chromium carbide precipitation and sensitization at grain boundaries.

Question 5

When welding dissimilar metals with different coefficients of thermal expansion, what primary problem can occur?

Accepted Answer

Residual stress and distortion upon cooling

Answer

Different thermal expansion rates cause unequal contraction upon cooling, generating residual stresses that can lead to cracking or distortion.

AWS Practice Test

AWS Practice Test

AWS Material Selection & Properties 2