AIT Material Science 5

Question 1

Which material property is described by the area under a stress-strain curve up to the fracture point?

Accepted Answer

Toughness

Answer

Toughness is the energy per unit volume a material can absorb before fracturing, represented by the total area under the stress-strain curve.

Question 2

What is the main difference between low-carbon steel and high-carbon steel in a trade setting?

Accepted Answer

Low-carbon steel is more weldable but less hard than high-carbon steel

Answer

Low-carbon steel (mild steel) is easier to weld and more ductile, while high-carbon steel is harder and stronger but less weldable.

Question 3

What is galvanic corrosion and how is it prevented?

Accepted Answer

Corrosion from dissimilar metals in electrical contact in the presence of an electrolyte; prevented by isolation or matching metals

Answer

Galvanic corrosion occurs when two dissimilar metals are in electrical contact in an electrolyte, with the less noble metal corroding faster; using insulating gaskets or compatible metals prevents it.

Question 4

In an apprenticeship context, why is it important to verify material certifications (Mill Test Reports) before use?

Accepted Answer

To ensure the material meets required chemical and mechanical property standards for the application

Answer

Mill Test Reports (MTRs) confirm that the material's chemical composition and mechanical properties meet the specified standards, ensuring safety and code compliance.

Question 5

Which heat treatment is applied to relieve residual stresses in welded structures without significantly changing hardness?

Accepted Answer

Post-weld heat treatment (stress relieving)

Answer

Post-weld heat treatment (PWHT) or stress relieving heats the weldment to a temperature below the critical point and holds it there to reduce residual stresses without major hardness changes.

(AIT) Apprenticeship and Industry Training Practice Test

(AIT) Apprenticeship and Industry Training Practice Test

AIT Material Science 5