Flashcards in Chapter 17 Deck (12):
Define: Metal Forming
Includes a large group of manufacturing processes in which plastic deformation is used to change the shape of metal workpieces
Define: Deformation Processes
Generally characterized by significant deformations and massive shape changes:
Define: Bulk vs. Sheet
Bulk: the work parts that have low area-to-volume ratio
Sheet: The surface area-to-volume ratio is very high
Compressive deformation process in which the thickness of a slab or plate is reduced by two opposing cylindrical tools called rolls.
A workpiece is compressed between two opposing dies, so that the die shapes are imparted to the work. Traditionally a hot working process, but sometimes done cold.
Compression process in which the work metal is forced to flow through a die opening, thereby taking the shape of the opening as its own cross section.
The diameter of a round wire or bar is reduced by pulling it through a die opening.
A part produced from from sheet metal operations (press-working)
Define: Flow Stress
The strength property that determines forces and power required to accomplish a particular forming operation. Defined as the instantaneous value of stress required to continue deforming the material to keep the metal "flowing"
Define: Average Flow Stress
Average value of stress over the stress-strain curve from the beginning of strain to the final (maximum) value that occurs during deformation.. (Y = Ke^n) / (1+n)
Define: Cold vs. Warm vs Hot Working
Cold: is metal forming performed at room temperature or slightly above. Advantages - greater accuracy, better surface finish, high strength and hardness, no heating required
Warm: is metal forming above .3*T_melt. Advantages - lower forces and power, more intricate work geometries, and need for annealing.
Hot: Metal forming and deformation at temperatures above the re-crystallization temperature.