AC

Alternating current. Electricity that flows in opposite directions at different times. AC switches direction 60 times per second, or 60 hertz, in the U.S.

alternating current

AC. Electricity that flows in opposite directions at different times. Alternating current switches direction 60 times per second, or 60 hertz, in the U.S.

ammeters

A device that measures current in an electrical circuit. Ammeters are sometimes built in to welding power sources.

amperes

A. The unit used to measure current or amperage. Amperes are also called amps.

arc

The area in which electricity transfers from the electrode to the workpiece. The arc generates the heat that melts the base metals.

arc blow

A condition that occurs when the arc does not follow its intended path from the electrode to the workpiece. Arc blow can cause poor quality weld beads.

arc length

The distance that electricity must travel from the tip of the electrode to the weld puddle. Arc length may depend on voltage.

arc welding

A fusion welding process that uses electricity to generate the heat needed to melt base and filler metals. Arc welding is the most commonly used welding process.

atoms

A tiny particle that makes up all materials. Atoms are the smallest distinguishable units of an element that retain the element's characteristics.

base metals

A metal to be welded to form a joint. Base metals' characteristics can greatly influence the strength of the final joint.

beads

The end product of a joint that has been welded. Bead formation depends on the movement of the electrode.

CC

Constant current. Electrical power in which current varies only slightly with changes in voltage. CC power is often used in shielded metal arc welding and gas tungsten arc welding.

circuit breakers

A device that detects excess current to prevent overheating in a circuit. A circuit breaker often contains a bimetallic strip that bends and trips a switch to open a circuit.

circuits

A controlled path through which electricity flows. Circuits consist of a source, path, load, and control.

compressed air

Air that has been forced into a small space at high pressure. Compressed air is often used to clean electronics.

conductor

A material that allows for the flow of electricity. Conductors are typically metals.

constant current

CC. Electrical power in which current varies only slightly with changes in voltage. Constant current power is often used in shielded metal arc welding and gas tungsten arc welding.

constant voltage

CV. Electrical power in which voltage varies only slightly with changes in current. Constant voltage power is often used for gas metal arc welding and flux-cored arc welding.

consumable electrode

A device that conducts electricity from the contact tip of the welding gun to the arc and melts into the weld as a filler metal. Consumable electrodes are used in GMAW and FCAW.

current

I. The amount of electricity flowing in a circuit. Current is measured in amperes.

current output

The maximum amount of current that a given power source can provide. Current output helps determine how much heat a power source can generate.

CV

Constant voltage. Electrical power in which voltage varies only slightly with changes in current. CV power is often used for gas metal arc welding and flux-cored arc welding.

DC

Direct current. Electricity that flows in one direction. DC is typically used for GMAW and FCAW.

DC electrode negative

DCEN. Current that always flows in one continuous direction with straight polarity. With DC electrode negative polarity, electricity flows from the negative electrode to the positive workpiece.

DC electrode positive

DCEP. Current that always flows in one continuous direction with reverse polarity. With DC electrode positive polarity, electricity flows from the negative workpiece to the positive electrode.

DCEN

DC electrode negative. Current that always flows in one continuous direction with straight polarity. With DC electrode negative polarity, electricity flows from the negative electrode to the positive workpiece.

DCEP

DC electrode positive. Current that always flows in one continuous direction with reverse polarity. With DC electrode positive polarity, electricity flows from the negative workpiece to the positive electrode.

deposition rates

The rate at which filler metal melts off the electrode into the weld puddle. Deposition rates can be measured in pounds per hour or in grams per minute.

direct current

DC. Electricity that flows in one direction. Direct current is typically used for GMAW and FCAW.

directly proportional

A relationship in which one number increases or decreases at the same rate and in the same ratio as another number. Directly proportional is the opposite of inversely proportional.

duty cycle

The amount of time in a ten-minute period that an electrical device can operate without overheating. Duty cycles are given as a percentage of the ten-minute period.

electric shocks

The flow of electricity through the body. Electric shock can be fatal.

electrical box

A metal cabinet in a building where power from the electrical distribution system enters and is distributed throughout the building. The electrical box connects to every circuit and device in the building.

electrical burn

A burn caused by the flow of electrical current through tissue or bone. Electrical burns may occur when handling wiring or electrical equipment that has been improperly maintained.

electricity

A form of energy created by the movement of electrons. Electricity can be converted into light, heat, or motion.

electrode

A device that conducts electricity to the arc in arc welding. Electrodes may also serve as filler metal.

electrode cable

The path used in arc welding to conduct electricity between the power source and the electrode. The electrode cable must be in good condition and installed correctly to prevent injury.

electrode holders

An insulated handle that clamps onto an electrode. The electrode holder must be dry and in good condition.

electromotive force

The electrical force or pressure that causes current to flow in a circuit. Electromotive force is also called voltage.

electrons

A negatively charged particle that orbits the nucleus of an atom. Electrons flowing between atoms creates electricity.

energy efficient

Having an energy output that is close to the total energy supplied. Energy efficient devices do work using smaller amounts of electricity, which costs less.

faults

A dangerous electrical condition that prevents current from completing its circuited as intended. Electrical faults include short circuits and open circuits.

FCAW

Flux-cored arc welding. An arc welding process that uses a continuously fed consumable electrode that contains flux at its core. FCAW is either a semi-automatic or automatic process.

filler metal

Metal deposited into the weld joint in fusion welding. Filler metal adds to the strength and mass of the welded joint.

flat position

The welding position in which the electrode is positioned directly above the joint. Flat-position welding situates the face of the weld horizontally.

flux-cored arc welding

FCAW. An arc welding process that uses a continuously fed consumable electrode that contains flux at its core. Flux-cored arc welding is either a semi-automatic or automatic process.

formula

A general fact or principle that is expressed mathematically. Formulas represent known equations using letters, numbers, and/or symbols.

gas metal arc welding

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

grounding

A means of providing a safe alternate return path for current that automatically disconnects power if a fault prevents current from flowing like normal. Grounding protects the electrical system and substantially reduces the risk of electric shock.

grounding conductor

The wire that provides a low-resistance path to ground for fault currents. Grounding conductors are usually bare copper or covered with green insulation.

grounding pin

The longest metal prong of a typical electrical plug. The grounding pin connects to a grounding conductor in the power system when plugged into an outlet.

heat distortion

An undesirable physical change in a material due to excessive temperature changes. Heat distortion may be caused by excessive current.

hot wire

The wire that provides power to an electrical device or load. The hot wire is usually covered with black insulation.

incomplete fusion

The lack of complete integration between the weld metal and base metal or adjoining weld beads. Incomplete fusion can create gaps, which may lead to cracks and joint failure.

insulation

Material that resists the flow of electricity. Insulation can prevent electric shock when used properly.

insulators

A material that resists the flow of electricity. Insulators include rubber and plastic.

inversely proportional

A relationship in which one number either increases as another number decreases or decreases as another number increases. Inversely proportional is the opposite of directly proportional.

inverter

An energy-efficient welding power source. Inverters are smaller than traditional power sources, but they have more electrical power.

load

A device in a circuit that converts electricity into another form of energy, such as heat, light, or motion. The load in an arc welding circuit is the arc.

low-carbon steel

A carbon steel that contains less than 0.30% carbon. Low-carbon steel is the most commonly welded metal.

magnetic field

The area in and around an energized conductor in which a magnetic force exists. Magnetic fields exhibit the powers of attraction and repulsion.

negative

An electric charge with a surplus of electrons. A negative charge is symbolized by a minus sign (-).

neutral wire

The wire that conducts power back to its source and completes the circuit. The neutral wire is usually covered with white insulation.

neutrons

A particle that has no charge. Neutrons are located in the nucleus of an atom.

nonferrous

Metal that does not contain iron. Nonferrous metals are more difficult to weld than ferrous metals.

Ohm’s Law

The universal truth that describes the relationship between voltage, current, and resistance. Ohm's Law states that one volt equals one amp times one ohm.

ohms

Ω. The unit used to measure electrical resistance. One ohm is equal to one amp divided by one volt.

out-of-position

Any welding position that is not classified or categorized. Out-of-position welding often uses electrodes that have smaller diameters to prevent spillage.

overhead position

The welding position in which welding that is performed from the underside of a joint. Overhead-position welding requires extra safety precautions.

path

A conductor that directs electricity in a circuit. The path used for welding is often copper wire.

penetration

The depth to which the arc heat can melt the joint below the surface of the base metals. Penetration partially depends on the amount of current.

personal protective equipment

PPE. Safety equipment that workers wear or use to prevent injury in the workplace. Personal protective equipment includes welding helmets, long gloves, and safety glasses.

polarity

Having two oppositely charged poles, one positive and one negative. Polarity determines the direction in which current flows.

pole

One end of a magnet or axis. Poles are either negative or positive.

porosity

The appearance of tiny holes on a weld bead as a result of trapped gas bubbles. Porosity can weaken a weld.

positive

An electric charge with a shortage of electrons. A positive charge is symbolized by a plus sign (+).

power source

The device that provides the electricity needed to perform arc welding. The power source is energized by the input voltage supply.

proportional

Having a constant ratio or relationship. Proportional values change in order to maintain the same ratio.

protons

A positively charged particle. Protons are located in the nucleus of an atom.

reactor

A device used in an electrical circuit to stabilize and increase the current of electrical power. Reactors adjust current to suitable levels for arc welding.

rectifier

A device used in an electrical circuit to convert AC power to DC power. Rectifiers allow electrical current to flow in only one direction.

resistance

R. The opposition to electrical current flow. Resistance is measured in ohms (Ω).

shielded metal arc welding

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

short circuiting

The condition in which current takes a shorter, unintended path between two conductors. Short circuiting causes excess current flow.

slag

Cooled flux that forms on top of the weld bead and must be chipped off. Slag occurs with welding processes that use flux.

source

The device that provides electrical power to a circuit. The source in an arc welding circuit is the power source.

spatter

Liquid metal droplets expelled from the welding process. Spatter can leave undesirable particles of metal on a workpiece surface.

thermal contact burns

A burn caused by fire or extreme heat. Thermal contact burns can be caused by faulty electrical equipment.

torches

A tool used to generate the flame or arc for welding. Torches hold the electrode for arc welding.

transformer

A device used in an electrical circuit to reduce the voltage of incoming electrical power. Transformers lower the voltage to suitable levels for arc welding.

travel speeds

The rate at which an electrode moves along a joint to make a weld. Travel speed determines the size of the weld bead.

trip

To automatically open a circuit to prevent damage and injury. Tripped circuit breakers indicate problems in electrical circuits.

undercut

A groove melted into the base metal at the weld toe or root that is left unfilled by weld metal. Undercut concentrates stress on the weld and can weaken it.

vaporize

To transform into a gas. Vaporization may occur due to the application of heat.

voltage

E. The electrical force or pressure that causes current to flow in a circuit. Voltage is also called electromotive force and is measured in volts.

voltmeters

A device that measures the voltage in an electrical circuit. Voltmeters are sometimes built in to welding power sources.

volts

V. The unit used to measure voltage. Volts indicate the electromotive force or voltage.

weld puddle

The small area of molten metal that forms during welding. Weld puddles are also called weld pools, molten pools, and molten puddles.

welding gun

A hand-held welding instrument that conducts electricity, guides the electrode, and, in some cases, releases shielding gas. Welding guns are used in some semi-automatic welding processes.

wire feed speed

WFS. The rate at which the wire electrode is fed through the welding gun. Wire feed speed is measured in inches per minute or millimeters per minute.

work

The result of a force applied to an object and the distance through which the force is applied. Work is equal to force multiplied by distance.

work cable

The path used in arc welding to conduct electricity between the power source and the workpiece. The work cable must be in good condition and installed correctly to prevent injury.

workpiece

The part being welded. A workpiece consists of the base metals in a welding operation.