ME Manufacturing Processes and Surface Engineering

Question 1

In metal casting, porosity defects are primarily caused by:

Accepted Answer

Gas entrapment and solidification shrinkage

Answer

Porosity in castings arises from dissolved gases released during solidification and from volumetric shrinkage as the metal transitions from liquid to solid.

Question 2

Hot working of metals is defined as plastic deformation carried out at temperatures:

Accepted Answer

Above the recrystallization temperature, so recrystallization occurs concurrently

Answer

Hot working occurs above the recrystallization temperature, so new strain-free grains continuously replace deformed grains, preventing strain hardening and allowing large deformations.

Question 3

In powder metallurgy, sintering after compaction serves to:

Accepted Answer

Bond powder particles together and reduce porosity via solid-state diffusion

Answer

Sintering heats the powder compact below its melting point, allowing solid-state diffusion to bond particles at contact points and reduce porosity, increasing density and strength.

Question 4

Which welding process uses a non-consumable tungsten electrode and an inert shielding gas to weld reactive metals like titanium and aluminum?

Accepted Answer

Gas Tungsten Arc Welding (GTAW/TIG)

Answer

GTAW (TIG welding) uses a non-consumable tungsten electrode with inert gas shielding (Ar or He), providing precise, clean welds ideal for reactive metals and thin materials.

Question 5

Electroplating deposits a metal coating on a substrate by:

Accepted Answer

Electrolytic reduction of metal ions from solution onto the cathode (workpiece)

Answer

In electroplating, the workpiece is the cathode; metal ions in the electrolyte are reduced and deposited onto it by passing an electrical current through the solution.

ME - Materials Engineer Practice Test

ME - Materials Engineer Practice Test

ME Manufacturing Processes and Surface Engineering