Metalworking, Heat Treatment, and Casting Processes

Comprehensive vocabulary flashcards covering heat treatment processes, metalworking and deformation techniques, casting stages, and expendable versus permanent mold casting methods.

Heat Treatment Processes

Processes that involve controlled heating and cooling to alter a metal's physical and mechanical properties, such as hardness, strength, and ductility.

Annealing

A heat treatment process that softens a metal and increases its ductility by heating it to a specific temperature and slowly cooling it, often inside the furnace itself; it relieves internal stresses, improves machinability, and enhances cold working properties.

Normalizing

A heat treatment process that refines the grain structure of a metal by heating it to a higher temperature and cooling it in still air, producing a uniform, fine-grained structure, improved toughness, and a material that is stronger and harder than annealed metal.

Hardening

A heat treatment process that significantly increases a metal's hardness and strength by heating a high-carbon metal to a specific temperature and then rapidly cooling it to make it highly resistant to wear and abrasion.

Tempering

A heat treatment performed after hardening where the hardened metal is reheated to a lower temperature and then cooled to relieve internal stresses, reduce brittleness, and increase toughness.

Quenching

The rapid cooling step of the hardening process in which heated metal is plunged into a medium such as oil, water, or brine to lock in the hardened crystalline structure.

Softening

A broad term that refers to any heat treatment process (such as annealing) that reduces a metal's hardness and makes it more malleable.

Metalworking Processes

Processes that involve shaping and deforming metal to achieve a desired form or size, often improving its mechanical properties.

Forging

A manufacturing process that shapes metal using localized compressive forces by heating the metal and hammering or pressing it into the desired shape to improve strength and grain structure.

Drop Forging

A type of forging where a heavy hammer or ram is dropped onto a heated workpiece to shape it.

Rolling

A metalworking process where metal is passed through a pair of rolls to reduce its thickness and achieve a uniform shape.

Hot Rolling

A rolling process performed at a temperature above the metal's recrystallization point to reduce the thickness of large slabs and produce specific shapes such as I-beams and channels.

Cold Rolling

A rolling process carried out at room temperature that requires more force but results in a smoother surface finish, increased hardness, enhanced strength, and greater dimensional accuracy.

Mold Creation (Casting)

The initial casting step where a negative impression of the final product is formed from materials such as sand, metal, plaster, or ceramic.

Solidification (Casting)

The casting step during which molten metal cools and solidifies inside the mold cavity, adopting the shape of the mold.

Expendable Mold Casting

A broad casting category in which the mold is destroyed to remove the casting, making it ideal for complex designs and low-volume production.

Permanent Mold Casting

A casting category that utilizes reusable molds, typically made from metal, allowing for higher production volumes.

Sand Casting

A common, versatile, and inexpensive expendable mold casting method using a mold made from sand and a binding agent, suitable for a wide range of metals, including those with high melting points.

Investment Casting (Lost-Wax Casting)

An expendable mold process for high-precision, intricate parts where a wax pattern is created, coated with ceramic material, and melted out to leave a hollow ceramic mold.

Shell Molding

A more automated version of sand casting in which a thin, hardened shell of sand and resin forms the mold, yielding better surface finish and higher dimensional accuracy than traditional sand casting.

Die Casting

A highly efficient permanent mold casting process in which molten metal is forced into a steel mold cavity under high pressure; best suited for non-ferrous metals with low melting points like aluminum, zinc, and magnesium.

Centrifugal Casting

A casting method where a metal mold rotates at high speed while molten metal is poured into the center, using centrifugal force to push the liquid outward against mold walls to produce dense, uniform cylindrical parts like pipes and tubes.

Gravity Casting

A permanent mold casting method where molten metal is poured into a reusable metal mold under the force of gravity, yielding high-quality castings with good dimensional control and mechanical properties.