aged

Heating a workpiece to a certain temperature to cause a change in its grain structure. Aged metals have increased hardness.

age-hardenable nickel alloys

Nickel alloys that can be hardened through heat treatment such as precipitation hardening. Age-hardenable nickel alloys usually contain aluminum or molybdenum.

alloys

A metal with purposefully added elements to enhance its mechanical and physical properties. Alloy can also refer to an element added to metal.

aluminum

A silver-white metal that is soft, light, and thermally conductive. Aluminum is corrosion resistant, has a high strength-to-weight ratio, and has good weldability.

aluminum oxide

A chemical compound of aluminum and oxygen which forms a thin protective layer on the surface of aluminum when exposed to air. Aluminum oxide should be removed before welding.

amperage

A measurement that indicates the amount of current flowing in a circuit. Amperage is measured in amperes or amps.

arc

The area in which electricity jumps from the electrode to the workpiece. Arc heat melts the base metals and filler metal during welding.

arc welding

A joining process that uses the heat generated from electricity to melt filler metal and base metals to form a weld. Arc welding processes transfer heat effectively and are often used to weld nonferrous metals.

boiling point

The temperature at which a liquid changes to a vapor. The boiling point of zinc is below the melting temperature of most steel.

brass

An alloy of copper and zinc. Brass offers a balance of electrical and thermal conductivity and strength.

brittle

A material that has limited resistance to being stretched, formed, or drawn. Brittle materials are prone to cracking, which can lead to failure of a part or structure.

burnthrough

Holes or excessive melting in a metal caused by extremely high welding temperatures. Burnthrough is a particular concern in metals with low melting points.

carbon monoxide

A colorless, odorless, poisonous gas made of carbon and oxygen. Carbon monoxide can cause weld defects when absorbed by molten metal.

cast

A metal that has been poured as a liquid into a mold and cooled into a solid shape. Cast nickel alloys are often difficult to weld because of their high silicon content.

cold working

The shaping of metal at temperatures below the point of recrystallization. Cold working, also known as work hardening, adds strength and hardness.

composition

The contents of a metal or alloy, described as percentages of total weight. Composition effects mechanical and physical properties as well as weldability.

copper

A reddish metal that is very ductile, thermally and electrically conductive, and corrosion resistant. Copper is often used to make electrical wire.

copper oxides

A chemical compound formed by copper and oxygen. Copper oxides can precipitate at grain boundaries during welding and weaken metal.

copper-lead alloys

An alloy of copper and lead that has good machinability. Copper-lead alloys have the poorest weldability of all copper alloys because the toxic lead often contaminates the weld and the atmosphere.

copper-nickel alloys

An alloy of copper and nickel that is strong and hard. Copper-nickel alloys, also known as cupronickels, form good welds when welded with the proper procedures.

corrosion resistance

A material's ability to resist deterioration caused by exposure to an environment. Materials with good corrosion resistance include zinc and aluminium.

cracking

A fracture that develops in the weld after cooling. Cracking can be caused by excessive hardness in a weld or atmospheric contamination.

crystals

The regular, repeating patterns of atoms in a material. Crystals help determine the properties of a metal.

cupronickels

An alloy of copper and nickel that is strong and hard. Cupronickels, also known as copper-nickel alloys, form good welds when welded with the proper procedures.

defects

An irregularity in the specified and expected composition and structure of a weld. Defects can cause a part or structure to fail.

deforming

The separation between neighboring crystals that are oriented in different directions. Deforming can negatively affect the properties of a metal.

deoxidized copper

A copper containing a small percentage of an element that removes oxygen from a metal. Deoxidized copper is more weldable than pure copper.

deoxidizers

An element that removes oxygen from a metal. Deoxidizers, such as silicon or phosphorus, can be alloyed with a metal or added during the welding process in the filler metal or flux.

ductility

The measure of a material's ability to be stretched, drawn, or formed without fracturing. Ductility is an important factor in determining a metal's weldability.

electrical conductivity

A material's ability to conduct an electrical current. Nonferrous metals with good electrical conductivity include copper and aluminum.

electrode

A device that conducts electricity. The electrode can also act as filler metal in welding.

embrittlement

The formation of brittle areas in a material. Embrittlement can make metals more likely to crack.

fatigue

The weakening of metal caused by repeatedly applied force. Fatigue can weaken even very strong and hard metals over time.

ferrous metals

A metal in which iron is the main ingredient. Ferrous metals are the most commonly used metal.

filler metal

A type of metal sometimes added to the joint of a weld. Filler metal adds strength and mass to a weld and can be deposited by the electrode or added to the joint separately, manually, or by machine.

flux

A granular material used to protect the weld pool from atmospheric contamination. Flux is used in a number of welding processes.

flux-cored arc welding

FCAW. An arc welding process that uses a continuously fed consumable electrode that contains flux in a hollowed-out center. Flux-cored arc welding produces smooth and consistent weld joints.

furnaces

A self-contained metal structure that can be heated to exceptionally high temperatures. Specialized furnaces can be used to preheat base metals before welding.

fusion

The process of permanently joining two workpieces. Fusion can be accomplished through welding.

fusion zone

The area where the base metals and filler metals, if used, are permanently joined through welding. The fusion zone is the area of greatest temperature change in a weld.

galvanized steel

Steel that has been plated with zinc to improve corrosion resistance. Galvanized steel is used in applications subjected to harsh environmental conditions.

galvanizing

The process of adding a zinc coating to steel. Galvanized steel has superior corrosion resistance.

gas metal arc welding

GMAW. An arc welding process in which the bare wire electrode and inert shielding gas are fed to the weld through a welding gun. Gas metal arc welding is also referred to as MIG welding.

gas tungsten arc welding

GTAW. A very precise arc welding process that uses a nonconsumable tungsten electrode. Gas tungsten arc welding is also referred to as TIG welding.

GMAW

Gas metal arc welding. An arc welding process in which the bare wire electrode and inert shielding gas are fed to the weld through a welding gun. GMAW is also referred to as MIG welding.

grain boundaries

The place where two grains meet. Grain boundaries determine the microstructure of a metal.

grain structure

The relationship between the small, individual crystals in a metal. Grain structure, also known as microstructure, changes when the metal is exposed to welding temperature.

grains

An irregular arrangement of a group of crystals. Grains and their arrangement greatly affect a metal's properties.

grinding

The use of an abrasive to wear away at the surface of a workpiece. Grinding removes surface impurities or undesirable materials from a metal before welding.

GTAW

Gas tungsten arc welding. A very precise arc welding process that uses a nonconsumable tungsten electrode. GTAW is also referred to as TIG welding.

hardened

The process of improving a metal's ability to resist deformation from impact. Some metals can be hardened through heat treatment.

hardness

A metal's ability to resist indentation, penetration, and scratching. Hardness in a metal may change due to the heat generated during welding.

HAZ

Heat-affected zone. The portion of the base metal where the mechanical properties have been altered by the heat of welding even though the metal did not melt. The HAZ can be limited through heat treatments.

heat sinks

A device that cools an electrical system by dissipating heat. Heat sinks are commonly used to cool central processing units in computers.

heat treatments

The controlled heating and cooling processes used to change the structure of a material and alter its physical and mechanical properties. Heat treatments include preheating and post-heating processes.

heat-affected zone

HAZ. The portion of the base metal where the mechanical properties have been altered by the heat of welding even though the metal did not melt. The heat-affected zone can be limited through heat treatments.

heating torch

A device for directing the heating flame produced by the controlled combustion of fuel gases. Heating torches are used to preheat base metals.

heat-treatable alloys

An alloy that can be heated during or after welding to preserve or restore its strength. Copper alloys are common heat-treatable alloys.

hot cracking

A crack in the weld that is often caused by stress in thin materials during solidification. Hot cracking often occurs when welding copper alloys.

hydrogen

The lightest and most abundant element in the universe. Too much hydrogen near the weld metal can cause cracking.

inert

A chemically inactive substance that does not react with other materials. Inert gases can protect molten metal from atmospheric contamination.

interpass temperature

The temperature of the weld area before the next weld pass is made in a multiple weld pass procedure. Limiting interpass temperature can help limit heat input of a weld.

iron

A malleable, silver-gray metal that is highly magnetized. Iron is alloyed with carbon to make steel.

lead

A toxic, bluish-white metal that is very soft and ductile and is a poor conductor of electricity. Lead creates toxic fumes when welded.

magnesium

A grayish white, extremely light metal that is brittle and has poor wear resistance. Magnesium workpieces can only be welded to other magnesium workpieces with a similar composition because they form brittle compounds when joined to other metals.

malleability

A material's capacity to be stretched or shaped by force generated from objects like rollers or hammers. Malleability is an important characteristic of nonferrous metals such as copper.

manufacturing

The process of producing and shaping a product on a large scale, often through the use of large machinery. The manufacturing process can change a metal's properties.

mechanical properties

A characteristic of material that describes how it responds to applied force. Mechanical properties include ductility, strength, and hardness.

melting points

The temperature at which a solid becomes a liquid. The melting point of a metal affects its weldability.

microstructure

The relationship between the small, individual crystals in a metal. Microstructure, also known as grain structure, changes when the metal is exposed to welding termperature.

molybdenum

A strong, corrosion-resistant silvery metal. Molybdenum is the most commonly used refractory metal.

natural aging

The process of allowing a metal to rest at room temperature to change its grain structure and properties. Naturally aging a metal increases its strength and hardness.

nickel

A hard, ductile, silvery-white metal. Nickel adds strength, toughness, and impact resistance to other metals when added as an alloy.

niobium

A ductile, gray metal most often used as an alloy due to its superconducting properties. Niobium was formerly known as columbium.

nonferrous metals

A metal that does not contain a significant amount of iron. The most commonly used nonferrous metals are aluminum and copper.

non-heat-treatable alloys

An alloy that relies primarily on cold working to increase its strength properties. Magnesium alloys are common non-heat-treatable alloys.

nuclear magnetic resonance instruments

NMRI. A medical diagnostic tool that uses magnetic fields and radio waves to create a picture of the body. Nuclear magnetic resonance instruments often contain niobium.

physical properties

A characteristic of metal that describes how it responds to forces other than mechanical forces. Physical properties include thermal expansion, thermal conductivity, and electrical conductivity.

porosity

The introduction of gas that creates bubbles in the weld, which can lead to fracturing. Common causes of porosity are atmospheric contamination and excessive oxidation of the workpiece.

post-heating

The application of heat to the weld immediately after welding. Post-heating helps reduce stress in the weld metal.

post-weld heat treatments

A heat treatment applied after the welded workpiece has cooled completely. Post-weld heat treatments include annealing, stress relieving, and tempering.

precipitate

The separation of elements from a solution. The precipitating process increases the strength and hardness of metals.

precipitation hardening

The process of producing hardness and strength in an alloy through a series of controlled heating and cooling processes. The precipitation hardening process includes solution heat treating, quenching, aging, and cooling.

preheating

The application of heat to a base metal immediately before welding. Preheating helps reduce hardness in the metal.

pressure vessels

A container designed to hold liquids or gases at high pressures. Pressure vessels include gas canisters.

pure

A substance that is not mixed with any other material. A pure metal has different properties than an alloyed metal.

quenched

Rapidly cooling a workpiece through the use of oil, water, or air. Quenched metals retain the grain structure they developed before quenching.

radiation shields

A device that contains the harmful energy transmitted by radioactive material. Radiation shields are commonly used in many components in a nuclear power plant.

reactive metal

A type of metal subject to react chemically with elements such as oxygen, hydrogen, or nitrogen. Reactive metals include titanium, nickel, and magnesium.

recrystallization

The formation of a new grain structure in a metal. Recrystallization is sometimes a side effect of welding.

refractory metals

A metal with a superior heat, wear, and corrosion resistance. Refractory metals are typically metals that have a melting point greater than iron.

shielded metal arc welding

SMAW. An arc welding process that uses a flux-coated consumable rod electrode. Shielded metal arc welding is also referred to as stick welding.

shielding gas

An inert gas that is used to flood an area and prevent contamination during welding. Common shielding gases include argon and helium.

silicon

A nonmetallic element often found in sand and used to make glass. High amounts of silicon in weld metal can cause cracking.

slag

Cooled flux that forms on top of the weld bead. Slag protects the cooling metal and is chipped off after the weld has cooled.

soldering

A joining process in which a filler metal is melted at temperatures below 840°F (450°C) to form a joint between two base metals. Soldering is often used for delicate projects such as jewelry and electronics.

solution

A mixture in which a minor component, such as an alloying element, is evenly distributed in a major component such as a base metal of an alloy. Solutions can be created in alloys through heat treatment.

solution heat treatment

The first step of precipitation hardening where an alloy is heated to a temperature high enough to allow the alloying element to form a solution with the base metal. Solution heat treatment is the first step in precipitation hardening.

steel

A metal consisting of iron and carbon, often alloyed with other elements. Steel is the most common manufacturing metal.

strength

A general measure of how well a material withstands various mechanical forces. Types of strength include tensile, yield, and impact.

strength-to-weight ratios

The relationship between a material's strength and its weight. Strength-to-weight ratios are considered high when a metal is light and strong, such as aluminum.

stress

A force that attempts to deform an object. Types of stress include compression, shear, and tensile.

sub-zero

A temperature below 0° on the Fahrenheit scale (-18° on the Celsius scale). Exposure to sub-zero temperatures can affect the properties of a metal.

superconductor

A metal that can channel extraordinary amounts of heat and electricity with great efficiency. Superconductors are used in transportation and medical diagnosis systems.

tack welds

A weld made to hold the parts of a weld in proper alignment before the final welds are made. Tack welds are also used to aid in preheating.

tantalum

A hard, blue-gray metal that is inert to most chemicals. Tantalum has superior corrosion resistance.

thermal conductivity

The rate at which heat flows through material. Materials with superior thermal conductivity include aluminum and copper.

thermal expansion

The tendency of a material to increase in size as it increases in temperature. Every material has its own unique rate of thermal expansion.

tin

A soft, silver-white metal used in many alloys. Tin is often combined with copper to make bronze.

titanium

A silver-gray, strong, lightweight metal known for its corrosion resistance and strength-to-weight ratio. Titanium is often used in the aerospace and medical industries.

trailing shields

A device that attaches to a welding torch to extend shielding gas coverage. Trailing shields are used when welding metals that are particularly sensitive to atmospheric contamination.

tungsten

A dense, grayish-white metal with superior heat resistance. Tungsten has the highest melting point of any metal.

vacuum-assisted welding chambers

A machine that provides an inert gas atmosphere for welding reactive metals. Vacuum-assisted welding chambers are used for intricate welding procedures.

ventilation

A means of providing fresh air. Ventilation is essential for operator safety in many welding applications.

voltage

A measure of electrical pressure or potential known as electromotive force. Voltage is measured in volts.

warpage

The deformation of a workpiece. Warpage can be caused by selectively overheating a metal with high thermal conductivity.

wear resistance

The ability of a material to resist the gradual wearing away caused by abrasion and friction. Wear resistance is important in determining how long a material or part can safely perform a function.

weave

The movement of an electrode in a back and forth motion to deposit weld metal into a joint. Weaving creates an even layer of weld metal.

weld pool

The pool of molten metal created by the heat of the welding. Weld pool characteristics vary depending on the metal being welded.

weldability

The ability of a material to be welded under imposed conditions into a specific, usable structure. Weldability depends on a wide range of factors such as the metal being welded, joint thickness, and atmospheric conditions.

welding

The permanent joining of two metals through the use of heat or pressure. Welding can be used to join most nonferrous metals.

wire brush

A tool with wire filament used to clean the surface of a workpiece. Wire brushes can remove impurities that could contaminate the weld and cause defects.

work hardening

The shaping of metal at temperatures below the point of recrystallization. Work hardening, also known as cold working, adds strength and hardness.

workpiece

A part that is subjected to a manufacturing process such as welding or cutting. Any metal or metals being welded are referred to as workpieces.

wrought

A metal that has been bent, hammered, or physically formed into a desired shape. Wrought nickel alloys are often welded under the same conditions as certain types of steel.

zinc

A bluish-white metal that is corrosion resistant and has a relatively low melting point. Zinc is often used as a coating on steel.

zinc oxide

A chemical compound of zinc and oxygen. Zinc oxide is non-toxic, but the fumes it creates when welded are very hazardous.

annealing

The steady heating of a metal at a certain temperature above the recrystallization phase followed by a gradual cooling process. Annealing helps soften metals that have become too hard or brittle.

bronze

An alloy of copper and another alloying element, usually tin. Bronze is strong and highly corrosion resistant.

heat treatment

The controlled heating and cooling processes used to change the structure of a material and alter its physical and mechanical properties. Heat treatment includes preheating and post-heating processes.

annealing

The steady heating of a metal at a certain temperature above the recrystallization phase followed by a gradual cooling process. Annealing helps soften metals that have become too hard or brittle.

bronze

An alloy of copper and another alloying element, usually tin. Bronze is strong and highly corrosion resistant.

heat treatment

The controlled heating and cooling processes used to change the structure of a material and alter its physical and mechanical properties. Heat treatment includes preheating and post-heating processes.