Production Engineering Flashcards

Vocabulary-style flashcards covering the core concepts, material properties, testing methods, and manufacturing processes outlined in the Production Engineering course (BEM125).

Elasticity

The property of a material to regain its original shape after deformation when the external forces are removed.

Proportional limit

The maximum stress under which a material will maintain a perfectly uniform rate of strain to stress.

Elastic limit

The greatest stress that a material can endure without taking up some permanent set.

Yield point

The specific stress at which ductile metals flow and a relatively large permanent set takes place without a noticeable increase in load.

Ultimate strength

The maximum stress that any material can withstand before destruction.

Stiffness

The ability of a material to resist elastic deformation or deflection under stress; also called rigidity.

Ductility

The property of a material enabling it to be drawn into wire with the application of tensile load, usually measured by percentage elongation and percent reduction in area.

Brittleness

The property of a material breaking with little permanent distortion; materials with less than $5\%$ elongation are considered brittle.

Engineering Stress ($\sigma$)

Calculated using the formula $\sigma = \frac{P}{A_o}$, where $P$ is the load in Newtons and $A_o$ is the original cross-sectional area in $m^2$.

Engineering Strain ($\epsilon$)

The ratio of change in dimension to the original dimension, calculated as $\epsilon = \frac{l_f - l_o}{l_o} = \frac{\Delta l}{l_o}$.

True Strain ($\epsilon_T$)

Calculated using the natural logarithm of the ratio of instantaneous length to original length: $\epsilon_T = \ln\left(\frac{l_i}{l_o}\right) = \ln(1 + \epsilon)$.

Hook’s Law

States that when a material is loaded within its elastic limit (up to the proportional limit), stress is proportional to strain.

Modulus of Elasticity ($E$)

The ratio of tensile stress to tensile strain (or compressive stress to compressive strain), also known as Young’s modulus.

Brinell hardness test

A test method that consists of indenting the test material with a $10\,mm$ diameter hardened steel or carbide ball.

Vickers hardness test

A test method using a diamond indenter in the form of a right pyramid with a square base and an angle of $136$ degrees between opposite faces.

Rockwell hardness test

A test that uses minor and major loads to determine hardness based on the difference in depth of indentation from a zero-reference position.

Charpy test

An impact test where a standard notched bar is simply loaded as a beam to measure the energy required for fracture.

Ferrous metals

Metals which have iron as their main constituent, such as cast iron, wrought iron, and steel.

Non-ferrous metals

Metals which have a metal other than iron as their main constituent, such as copper, aluminum, zinc, lead, and tin.

Cast iron

An alloy of iron and carbon (with carbon content ranging from $1.7\%$ to $6.67\%$) obtained by re-melting pig iron in a cupola furnace.

Wrought iron

The purest form of iron, containing at least $99.5\%$ iron and minute threads of silicate slag, giving it a fibrous appearance.

Steel

An alloy of iron and carbon with a maximum carbon content of $1.7\%$, where carbon occurs in the form of iron carbide.

Blast furnace

A structure consisting of a hearth, bosh, stack, and top, used to produce crude (pig) iron from iron ore, coke, and limestone.

Bessemer Convertor

An ovoid steel container where impurities are removed from molten iron by oxidation with air blown through the mass to produce steel.

Monomer

A single repeating unit that joins with thousands of others in a polymerization reaction to form a polymer.

Thermo-Plastics

Plastics which can be repeatedly softened by heating and hardened by cooling, allowing them to be reprocessed safely.

Thermo-Setting Plastics

Plastics that undergo a non-reversible chemical change when hardened by heat and cannot be easily softened by reheating.

Extrusion

A process where liquefied plastic is forced through a die under pressure to create long, uniform solid or hollow complex cross-sections.

Injection Molding

A process where plastic pellets are fed into a heated cylinder and forced into a die chamber by a hydraulic plunger or rotating screw.

Blow Molding

A modified extrusion or injection process used to create hollow, thin-walled parts like beverage bottles by expanding a parison with air pressure.

Ceramics

A class of inorganic, nonmetallic solids composed of oxides, carbides, and nitrides that are subjected to high temperatures during manufacture.

Sintering

A controlled heat process where materials (oxides or metal powders) are consolidated into a dense, cohesive body without reaching the melting point; also called densification.

Powder metallurgy

A manufacturing process for creating products from powdered metals by compacting them in molds and then heating them (sintering).

Atomization

A powder production process where molten metal is forced through an orifice and hit by a high-pressure stream of gas or liquid to create fine particles.

Sand casting

A metal casting process characterized by using sand as the mold material, often mixed with a bonding agent like clay and water.

Green sand

A mixture of silica sand with $18\%$ to $30\%$ clay and a moisture content of $6\%$ to $8\%$.

Recrystallization

The process of forming new grains at the location of internal stresses caused by plastic deformation when the metal is heated sufficiently.

Hot Working

Mechanical working processes performed above the recrystallization temperature of the metal.

Cold Working

Mechanical working of a metal below its recrystallization temperature, which increases strength and hardness but decreases ductility.

Draft ($d$)

The thickness reduction in rolling, defined as the starting thickness ($h_o$) minus the final thickness ($h_f$).

Deep Drawing

A sheet metal forming process where a blank is radially drawn into a die by a punch; it is considered "deep" when depth exceeds the diameter.

Weldability

A property of a metal indicating the ease with which it can be joined by fusion with other similar or dissimilar metals.

Shielded Metal Arc Welding (SMAW)

A manual arc welding process where heat is produced between a flux-coated electrode and the workpiece.

Friction Welding

A solid-state welding process where heat is obtained from mechanically induced sliding motion between rubbing surfaces under axial pressure.