Introduction to Metal Manufacturing 180

additive manufacturing

AM. The process of joining or solidifying materials to make an object based on a three-dimensional computer model. Additive manufacturing methods typically build up layers of material to create an object.

alloy

A metal consisting of a mix of two or more elements, one of which must be a metal. Common alloys include cast iron, bronze, brass, and different types of steel.

AM

Additive manufacturing. The process of joining or solidifying materials to make an object based on a three-dimensional computer model. AM methods typically build up layers of material to create an object.

annealing

The heat treating of a metal to prevent it from becoming brittle. Annealing helps to increase ductility, improve formability, and reduce hardness.

anode

An electrical terminal that carries a positive charge. The positive charge of the anode draws in electricity.

basic oxygen furnace

BOF. A type of furnace that melts and purifies raw material using oxygen, coke, and flux. The most common type of basic oxygen furnace is the blast furnace.

billet

A mold shape that resembles an elongated square or rectangle. Billets are smaller than slabs.

binder jetting

An additive manufacturing method in which liquid binder is used to join powdered materials to create a part. Binder jetting can be utilized in the creation of cast molds.

blast furnace

The most common type of basic oxygen furnace. Blast furnaces are largely used to process iron ore.

bloom

A mold shape that resembles an elongated circle. Blooms are often formed by rolling a sheet of metal around itself.

brass

A nonferrous alloy containing copper and zinc. Brass has moderate strength and good corrosion resistance.

bronze

An alloy containing copper and tin. Bronze is strong and highly corrosion resistant.

carbides

A common cutting tool material created by combining carbon with a hard metal, such as titanium or tungsten. Carbide tools are the most commonly used tools in the metal cutting industry.

carbon

A common, nonmetallic element that is very strong and has high resistance to heat. Carbon content typically determines hardness in metal.

carbon monoxide

CO. A colorless, poisonous gas composed of carbon and oxygen. Carbon monoxide escapes a furnace during smelting.

carburizing

A surface treatment that fuses carbon to a metal. Carburizing adds hardness and increases resistance to wear.

cast

Metal that has been melted, shaped, and cooled. A cast may have a rough surface finish or irregular surfaces, which may require additional finishing processes after production.

cathode

An electrical terminal that carries a negative charge. The negative charge of the cathode causes electricity to flow out from it.

chemical reaction

A process in which one or more substances are changed due to the introduction of another substance. In smelting, oxygen is stripped from the raw materials through a chemical reaction.

coke

A carbon-based fuel used to heat a furnace. Coke can be obtained from oil refineries but may also form naturally during geological processes.

cold working

The shaping of metal below its recrystallization temperature. Cold working is used most often with malleable, ductile metals.

conformal cooling

The use of cooling channel configurations that curve and closely correspond to a part's shape. Conformal cooling allows a part to cool more uniformly, improving heat management, which can improve overall part quality.

continuous casting

A casting process that involves pouring molten metal into a mold continuously. In continuous casting, molten metal moves through the mold and cools as it moves further through the process.

corrosion

The gradual degrading or wearing away of material over time. Corrosion typically occurs when a material is exposed to oxygen, moisture, or other substances.

corrosion resistance

The ability of a material to resist destruction or deterioration due to chemical or environmental exposure. Corrosion resistance is a common property of nonferrous metals.

die casting

A thermal, high-pressure metal casting process that involves injecting molten metal into a mold at high velocity and pressure. In die casting, the mold is also called the die.

directed energy deposition

DED. An additive manufacturing method in which focused laser thermal energy is used to melt materials as they are deposited on a build platform. Directed energy deposition often uses metal powder or wire as build materials.

ductility

The ability of a metal to be drawn, stretched, or formed without breaking. Ductility is more common in softer metals.

ejector pins

A long pin that extends and retracts to force a solid, molded part out of a mold cavity. To prevent part deformation, the part must be completely cooled before ejector pins are activated.

electric arc furnace

EAF. A type of furnace that uses electricity to melt metal. Electric arc furnaces use rods to direct electricity to raw materials.

electrolysis

A process that passes an electric current through a substance to create a chemical change. Electrolysis is used to remove impurities from raw metals.

electrolytic cell

A chamber filled with liquid inside which electricity is used to drive electron flow between electric terminals. In an electrolytic cell, metal clings to one terminal in order to separate it from unwanted materials.

expendable

Intended to be used once and discarded. Expendable molds may be made of sand, plaster, or ceramic.

extraction site

A pit, quarry, or deposit where raw materials are located naturally and removed from. The extraction site is where mineral processing occurs.

ferrous metals

A metal that contains iron. Ferrous metals are the most commonly used metals in manufacturing.

finishing processes

The treatment of a surface to remove roughness and irregularities and improve its appearance. Finishing processes include sanding, filing, heat treating, cleaning, polishing, and painting.

flues

An escape duct for smoke and waste gas produced by a heat source. The angle of the flues in a reverberatory furnace allow flames to bounce back and reverberate.

flux

A substance used in ore smelting to promote fluidity and remove impurities in the form of slag. Limestone is a common type of flux used in the production iron.

formability

The ability of a metal to withstand changes to its size or shape without being damaged or breaking. Formability is an important property in working metal.

foundry sand

A material consisting of sand mixed with additives, such as clay, coal, and water. Foundry sand is used to build molds in sand casting.

fuels

A material that produces heat. Coke and electricity are examples of fuels used in smelting.

gangue

An unwanted substance that surround minerals in ore, such as sand or rock. Gangue impurities are removed during the concentration process.

grain structure

The size, structure, and orientation of small, hard particles in a metal or alloy. Grain structure helps determine the properties of a metal.

graphite

A black, soft form of carbon that conducts electricity. Graphite rods are used in an electric arc furnace to direct the path of electricity toward raw materials.

hot working

The shaping of metal above its recrystallization temperature. Hot working is used most often with steel.

ingot

A mold shape that resembles an elongated trapezoid. Ingots often require further processing to be shaped into usable parts.

investment casting

A casting process that creates intricate shapes using an expendable wax pattern and an expendable ceramic mold. Investment casting is also called lost-wax casting.

limestone

A sedimentary rock that is used in furnaces to remove impurities from ore. Limestone is a common type of flux used in basic oxygen furnaces.

lubricated

Covered with a substance that reduces friction. When a mold is lubricated, it makes it easier for the cast to be removed.

malleability

The ability of a material to be formed or shaped through impact or pressure. Materials with higher malleability do not break or fracture easily.

malleable

Able to be formed or shaped through impact or pressure. Malleable metals do not break or fracture easily.

manufacturing

Any process used to turn raw materials into finished parts or products. Manufacturing generally refers to processes completed by industrial companies or facilities.

metallurgical processes

Any process used in the extraction of metal in their pure form. Metallurgical processes such as mineral processing and smelting are used to remove impurities.

mineral processing

Any mechanical process used to separate desired metals from ore. Mineral processing occurs at the site of extraction to remove unwanted byproduct from ore.

mining

Extracting raw materials from the earth. Mining includes processes used to obtain raw metal ore.

mold

A hollow cavity used to shape material. The mold of a metal cast is filled with liquid metal, which takes the shape of the mold as it solidifies.

molten

The liquid state of metal. Molten metal can be cast into usable forms.

nonferrous metals

A metal that does not contain iron. Common nonferrous metals include aluminum, copper, titanium, and nickel.

ore

A naturally occurring rock or sediment that contains metal within it. Extracting metal from ore is the first step in metal fabrication.

oxide

A chemical compound containing oxygen and one other element. Common oxides that escape through the smelting process include carbon monoxide and carbon dioxide.

oxidize

To chemically combine and react with oxygen. Oxidization creates corrosion, such as rust, that leaves metals unable to be used.

parallel

Extending in the same direction and equidistant at all points. Because the heat source is parallel with the raw material in a reverberatory furnace, the heat source and raw material never come in contact with one another.

pattern

A replica of the part or cast that is used to create a negative impression in a mold. Creating a pattern and mold is the initial step in the casting process.

pickle liquor

An acidic solution used to remove impurities. Once used, pickle liquor is considered a hazardous waste.

pickling

The soaking of metal in an acid to remove the impurities on its surface. Pickling utilizes a specific type of acid called pickle liquor.

powder bed fusion

PBF. An additive manufacturing process that uses adhesives, heat, or light to bond areas in a container of powdered metal. Powder bed fusion often uses either lasers or electron beams as thermal energy sources.

powder metallurgy

The process of creating parts by compressing and heating granulated metal. Powder metallurgy creates parts without metal removal processes.

properties

A characteristic of a material that distinguishes it from other materials. Properties are often categorized as either mechanical properties, which describe how a material responds to external forces, or physical properties, which describe basic qualities of the material.

raw materials

An unprocessed material that has not been manufactured. Raw materials include metals that occur naturally in the earth.

recrystallization temperature

The temperature at which new grains are formed in a metal. Every metal has its own specific recrystallization temperature.

reusable

Intended to be used over and over again. Reusable molds are typically made of metal.

reverberatory furnace

A type of furnace that uses a flame to heat raw material without directly contacting it. Reverberatory furnaces are primarily used with nonferrous metals.

sand casting

The process of making a part by pouring molten metal into a sand mold. The mold in sand casting is expendable.

sensors

A device that detects changes in physical conditions such as heat or pressure. A sensor can track changes in temperature, the presence of corrosion, or whether a mold has been over- or under-filled.

sintering

Creating a solid metallic part by pressing powders into a desired shape, then heating them. Sintering creates parts with very uniform compositions.

slab

A mold shape that is much wider than it is thick. The width of a slab is at least twice its thickness.

slag

The rock-like waste that separates from molten material. Slag appears as a layer that floats over top molten metal in a furnace.

slurry

A thick mixture of liquid and suspended solids. Investment casting makes a mold by surrounding a pattern made of wax in a slurry.

smart technology

Technology capable of sending and receiving data without human intervention. Smart technology is useful in monitoring metallurgical processes to prevent loss of product and corrosion.

smelting

A process that heats and melts ore to extract metal from it. Smelting takes place in a smelting furnace.

solution

A mixture of liquids. Electrolytic solutions are capable of conducting an electric current.

strength

A material's ability to resist forces that attempt to break or deform it. Strength is an important mechanical property for many manufactured parts.

tap hole

A hole through which molten metal escapes. The tap hole is usually positioned at or near the bottom of a furnace.

trapezoid

A shape with only two parallel sides. The nonparallel sides of a trapezoid slant toward each other.

wear resistance

A material's ability to resist the gradual wearing away caused by abrasion and friction. Increased wear resistance can lengthen the life of a material.

works

Forms and shapes a metal part using pressure. Desirable properties can be obtained by working metal.