Processing and Manufacturing Flashcards
6 cards from real ME practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Processing and Manufacturing flashcards as text
In metal casting, porosity defects are primarily caused by:
Answer: Gas entrapment or shrinkage during solidification
Porosity in castings arises from dissolved gases released during solidification or from volumetric shrinkage as metal contracts when changing from liquid to solid.
Hot working of metals is performed above the recrystallization temperature primarily to:
Answer: Allow dynamic recrystallization, maintaining ductility at high deformation levels
Hot working enables large deformations with lower forces because recrystallization continuously replaces deformed grains with new equiaxed grains, preventing work hardening.
Which powder metallurgy step bonds metal powders into a dense solid part using heat and/or pressure below the melting point?
Answer: Sintering
Sintering heats compacted powder to typically 70-90% of the melting point, activating diffusion that bonds particles and densifies the compact without melting.
The purpose of annealing a cold-worked metal is to:
Answer: Restore ductility by reducing dislocation density via recovery and recrystallization
Annealing heats cold-worked metal to allow recovery (stress relief) and recrystallization (new strain-free grain formation), restoring ductility and reducing hardness.
Investment casting (lost-wax casting) is preferred for complex shapes because:
Answer: It uses an expendable wax pattern to produce intricate, near-net-shape parts
In investment casting, a wax pattern is coated with ceramic slurry, the wax is melted out, and metal is poured into the cavity, allowing complex geometries with excellent surface finish.
In extrusion manufacturing, the extrusion ratio is defined as:
Answer: Billet cross-sectional area divided by product cross-sectional area
The extrusion ratio (R) is the ratio of the billet cross-sectional area to the extrudate cross-sectional area, indicating the degree of deformation applied.