AWS Material Selection & Properties 3

Question 1

Which aluminum alloy series is considered non-heat-treatable?

Accepted Answer

5xxx series (magnesium alloys)

Answer

The 5xxx series aluminum alloys are strengthened by work hardening rather than heat treatment, making them non-heat-treatable.

Question 2

What is the primary alloying element in 4340 alloy steel?

Accepted Answer

Nickel, chromium, and molybdenum

Answer

AISI 4340 is a nickel-chromium-molybdenum alloy steel known for its high strength, toughness, and deep hardenability.

Question 3

In cast iron welding, what makes gray cast iron particularly susceptible to cracking?

Accepted Answer

Brittle graphite flakes acting as stress concentrators

Answer

Gray cast iron contains graphite in flake form, which acts as stress concentrators and creates brittleness, requiring preheat and slow cooling to prevent cracking.

Question 4

What does ASTM A36 designate in structural steel specification?

Accepted Answer

A common mild structural steel with 36 ksi minimum yield strength

Answer

ASTM A36 is a mild carbon structural steel with a minimum yield strength of 36,000 psi (36 ksi), widely used in construction and general fabrication.

Question 5

Which condition describes 'temper embrittlement' in alloy steels?

Accepted Answer

Reduced toughness from slow cooling through 375-575°C temperature range

Answer

Temper embrittlement occurs when certain alloy steels are slowly cooled or held in the 375–575°C range, causing impurity segregation to grain boundaries.

AWS Practice Test

AWS Practice Test

AWS Material Selection & Properties 3