Manufacturing Processes - Vocabulary Flashcards

Vocabulary practice flashcards covering metal forming, forging, rolling, extrusion, drawing, press work, and casting processes.

Cold Working

Plastic deformation of metals and alloys below their recrystallization temperature, inducing internal stresses and improving dimensional accuracy without surface oxidation or tarnishing.

Hot Working

Plastic deformation carried out above the recrystallization temperature where recovery and recrystallization take place along with strain hardening, resulting in no internal residual stresses.

Strain Hardening

Phenomenon where mechanical working improves material mechanical properties such as ultimate tensile strength, wear resistance, hardness, and yield point, while lowering ductility.

Soaking Time (Forging)

The duration allowed for heat to travel from the surface to the core of a workpiece prior to hot forging, calculated as $30\,\text{minutes}$ for every $12\text{--}15\,\text{mm}$ of cross-sectional thickness.

Open Die Forging

A forging process where metal is never completely enclosed or confined on all sides, typically produced using flat, double V, flat and V, or swage dies.

Impression Die Forging

A process where half of the impression is made in the top die and half in the bottom die, squeezing out excess material as flash which provides cushioning for the dies.

Closed Die Forging

A forging method suitable for mass production that is similar to impression die forging but eliminates flash by carefully controlling the material volume.

Bloom

The first product obtained from the breakdown of ingots in rolling, having a cross-sectional size ranging from $150\,\text{mm}$ square to $250\,\text{mm}$ square, or a $250 \times 300\,\text{mm}$ rectangle.

Billet

A rolled product derived from a bloom, with cross-sectional dimensions varying from $50\,\text{mm}$ square to $125\,\text{mm}$ square.

Absolute Draught

The reduction in thickness during rolling, defined mathematically as $\Delta h = (h_0 - h_1)\,\text{mm}$, where $h_0$ is the original thickness and $h_1$ is the final thickness.

Four High Mill

A rolling mill configuration consisting of four horizontal rolls: two smaller working rolls in contact with the workpiece and two much larger backup rolls supporting them.

Ring Rolling

A specialized rolling process used to produce seamless rings such as inner and outer bearing races or steel tyres for railway wheels.

Forward Extrusion

Also known as direct extrusion, a process where the material slides along the chamber wall and is forced through the die in the same direction as ram motion.

Backward Extrusion

Also known as indirect extrusion, a process where the mass of material does not move while the die moves, requiring $25\text{--}30\%$ less extruding force than direct extrusion.

Hooker Extrusion

A two-stage cold extrusion process, also known as the extrusion down method, used to manufacture small, thin-walled seamless tubes of aluminium and copper.

Hydrostatic Extrusion

A direct cold extrusion method where fluid pressures between $1000$ and $3000\,\text{MPa}$ are applied via fluid media to deform relatively brittle materials.

Impact Extrusion

A cold extrusion technique where a high-velocity punch strikes the center of a blank inside a die, forcing material to deform upward through the annular space between punch and die.

Wire Drawing

A metal forming process where wire is pulled through a series of dies of progressively smaller diameters, causing plastic deformation and strain hardening.

Mannesmann Rotary Piercing Process

A seamless tube-making process where a heated round billet is rotated and pulled forward between two tapered rolls inclined at approximately $6^\circ$ relative to the billet axis.

Spring Back

The elastic response of a metal sheet at the end of a bending operation where the bend angle tends to open out after the bending force is retrieved.

Deep Drawing

A sheet metal operation converting a flat sheet or plate into a cup shape by pressing the center with a circular punch into a matching cup-shaped die.

Guillotine Shear

A machine equipped with two straight, hardened die-steel blades finished by grinding to shear sheet metal smoothly.

Fettling

The foundry operation performed after retrieving a casting, consisting of cleaning the casting and cutting off risers, runners, and gating channels.

Moulding Sand Composition

Standard foundry mixture comprising approximately $75\%$ silica, $10\text{--}15\%$ clay, $2\text{--}5\%$ bentonite, $5\text{--}10\%$ coal dust, and $6\text{--}8\%$ moisture.

Gating System

The passage provided in a mold through which molten metal flows into the mold cavity, including sprue, runner, choke, skim bob, and ingate.

Cupola

A vertical furnace lined with refractory lining and encased in a steel shell used specifically for melting cast iron in foundry operations.