ME Manufacturing Processes and Surface Engineering 2

Question 1

The heat-affected zone (HAZ) in welding is the region that:

Accepted Answer

Was not melted but experienced microstructural changes due to welding heat

Answer

The HAZ is the base metal adjacent to the fusion zone that did not melt but whose microstructure and properties were altered by the welding thermal cycle.

Question 2

Shot peening improves the fatigue life of metal components by:

Accepted Answer

Introducing compressive residual stresses in the surface layer that retard fatigue crack initiation and growth

Answer

Shot peening bombards the surface with small spherical media, causing localized plastic deformation that induces beneficial compressive residual stresses, which oppose tensile fatigue stresses.

Question 3

Investment casting (lost-wax casting) is preferred for:

Accepted Answer

Near-net-shape production of complex, high-tolerance parts in superalloys and stainless steel

Answer

Investment casting uses an expendable wax pattern coated in ceramic to produce intricate, near-net-shape parts with excellent surface finish, suitable for superalloys and aerospace components.

Question 4

Cold drawing of metal wire through a die produces a product with:

Accepted Answer

Increased strength and hardness due to strain hardening, but reduced ductility

Answer

Cold drawing at room temperature plastically deforms the wire, increasing dislocation density (strain hardening), which raises strength and hardness while reducing ductility.

Question 5

Chemical vapor deposition (CVD) is commonly used to apply hard coatings (e.g., TiN, TiC) to cutting tools because:

Accepted Answer

It produces dense, adherent coatings with excellent uniformity even on complex geometries at elevated temperatures

Answer

CVD deposits hard, wear-resistant ceramic coatings by thermally decomposing gas-phase precursors on the heated tool substrate, producing dense, conformal coatings with strong adhesion.

ME - Materials Engineer Practice Test

ME - Materials Engineer Practice Test

ME Manufacturing Processes and Surface Engineering 2