Electrode Selection 265

AC

Alternating current. Current that reverses direction at regularly recurring intervals of time. AC supplied by the U.S. electrical grid switches direction 120 times per second, or at 60 hertz (Hz).

active

A substance that chemically reacts with other elements. Active gases such as carbon dioxide and oxygen are used as shielding gas for welding.

alloying elements

A material that is intentionally added to a metal in order to change its properties. Alloying elements can improve the strength, ductility, hardness, and toughness of a finished weld.

alloys

A metal consisting of a mixture of two or more elements, one of which must be a metal. Alloys combine the beneficial properties of the mixed elements.

alternating current

AC. Current that reverses direction at regularly recurring intervals of time. Alternating current supplied by the U.S. electrical grid switches direction 120 times per second, or at 60 hertz (Hz).

aluminum

A silver-white, nonferrous metal that is soft, light, and electrically conductive. Aluminum is often one of the main deoxidizers in flux material.

American Welding Society

AWS. The nonprofit organization that regulates the industrial standards for welding. The American Welding Society also promotes the welding industry in the United States.

amperage

The amount of current flowing in a circuit. Amperage is measured in amperes (A), or amps.

arc

The area in which electricity moves between the electrode and the workpiece. The arc generates heat that melts the base metals and filler metal during welding.

arc welding

A group of welding processes that use electricity to generate the heat needed to melt base metals and any filler metal. Arc welding is portable and economical, making it the most common form of welding.

argon

Ar. A heavy, inert gas commonly used for shielding in arc welding processes. Argon is much heavier than air and can effectively shield the weld area.

AWS

American Welding Society. The nonprofit organization that regulates the industrial standards for welding. The AWS also promotes the welding industry in the United States.

axial spray transfer

GMAW-Spray. A type of metal transfer in which the metal at the end of the electrode melts into small, fine droplets that transfer to the weld pool. Axial spray transfer creates a stable arc and little spatter.

balled

Having a round, spherical, or hemispherical shape. Balled GTAW electrode tips are used for AC welding.

calcium

A soft, ductile, silver-gray metal that reacts quickly with atmospheric oxygen. Calcium acts as a deoxidizer and is often found in flux for welding.

carbon

A common, nonmetallic element that is very strong and resistant to heat. Carbon is added to the filler metal in an SMAW electrode to help strengthen the joint.

carbon dioxide

CO₂. A heavy, active gas composed of carbon and oxygen that is commonly used for shielding in arc welding processes. Carbon dioxide breaks down into carbon monoxide in the heat of the arc.

carbon steel

An alloy of iron and carbon that contains less than 3% other alloying elements. Carbon steels are divided into low-carbon, mild, medium-carbon, and high-carbon steels.

cellulose

An insoluble material made from fibers found in plants. Cellulose is used in the flux coatings of some SMAW electrodes.

ceriated electrodes

A tungsten electrode that contains a small percentage of cerium. Ceriated electrodes are usually 2% cerium and 98% tungsten and may be used as a replacement for thoriated tungsten.

cerium

A rare-earth metal that is soft and ductile and oxidizes easily. Cerium is often combined with tungsten to make ceriated GTAW electrodes.

chartreuse

A bright greenish-yellow color. Chartreuse is used to indicate some multi-oxide welding electrodes.

chromium

A steel-gray, nonferrous metal that is hard and shiny. Chromium is often used as an alloying element because it has excellent corrosion resistance.

collet

The component of the torch that holds the electrode. The collet and the collet body make up the two-piece collet set.

collet body

The component of the torch that holds the collet in place. The collet body and the collet make up the two-piece collet set.

composite

An electrode made of more than one metal. Composite electrodes are identified with a “C” in the AWS electrode classification system.

consumable electrode

An electrode that conducts electricity to the arc but also melts into the weld as filler metal. Some consumable electrodes also provide shielding that protects the arc and weld pool.

copper

A reddish metal that is very ductile, thermally and electrically conductive, and corrosion resistant. Copper is used to coat GMAW electrodes.

corrosion resistance

The ability of a material to resist deterioration and chemical breakdown due to surface exposure in a particular environment. Corrosion resistance can be improved by adding alloying elements like chromium and nickel.

cracking

Fracturing that develops in a weld after solidification is complete. Welds with high hardness are prone to cracking.

cut lengths

A unit of filler metal that is manually added to the weld pool by the welder. Cut lengths, also known as filler rods, usually match the composition of the base metal and can add beneficial mechanical properties to the finished joint.

DC

Direct current. Current that flows in one continuous direction. DC can be used for most welding methods.

DCEN

Direct current electrode negative. Current that always flows in one continuous direction from the negative electrode to the positive workpiece. DCEN polarity is also known as straight polarity, but this is a nonstandard term.

defects

An irregularity in the specified and expected composition of a weld that exceeds the part design's tolerances. A defect is an unacceptable discontinuity.

denitrifiers

A material that removes nitrogen from the molten weld pool and arc. Denitrifiers prevent nitrogen from ruining a weld bead.

deoxidizers

A material that removes oxygen from the molten weld pool and arc. Deoxidizers prevent oxygen from ruining a weld bead.

deposition rate

The rate at which filler metal is deposited into the molten weld pool to form a weld. The deposition rate can be measured in pounds per hour (lb./hr.) or in kilograms per hour (kg/hr).

diffusible hydrogen

The maximum amount of hydrogen, given in milliliters (mL), that will be present per 100 grams of weld metal. An electrode's classification may specify its diffusible hydrogen.

direct current

DC. Current that flows in one continuous direction. Direct current can be used for most welding methods.

direct current electrode negative

DCEN. Current that always flows in one continuous direction from the negative electrode to the positive workpiece. Direct current electrode negative polarity is also known as straight polarity, but this is a nonstandard term.

direct current electrode positive

DCEP. Current that always flows in one continuous direction from the negative workpiece to the positive electrode. Direct current electrode positive polarity is also known as reverse polarity, but this is a nonstandard term.

ductility

A material's ability to be drawn, stretched, or formed without breaking. Ductility generally increases as hardness decreases.

electrical conductivity

A material's ability to convey electricity. Electrical conductivity allows welding electrodes to create an arc, and electrodes with higher conductivity tend to have very stable arcs.

electrode

A component in an electrical circuit that conducts electricity. A welding electrode generates the welding arc and can also act as filler metal.

electrode ovens

An enclosed heating device used to store and recondition welding electrodes. Electrode ovens maintain different temperatures depending on the type of electrode.

fast-fill electrodes

An SMAW electrode designed to lay down a large amount of weld metal in a small amount of time. Fast-fill electrodes are useful for creating wide, strong welds.

fast-freeze electrodes

An SMAW electrode designed to lay down a weld bead that solidifies quickly. Fast-freeze electrodes are useful for vertical and overhead welding.

FCAW

Flux-cored arc welding. An arc welding process that uses a continuously fed, consumable wire electrode with an inner core of flux. FCAW includes self-shielded flux-cored arc welding (FCAW-S) and gas-shielded flux-cored arc welding (FCAW-G).

FCAW-G

Gas-shielded FCAW. A type of FCAW that uses a flux-filled, tubular wire electrode and an external shielding gas to protect the weld area. FCAW-G electrodes require less flux than FCAW-S electrodes.

FCAW-S

Self-shielded FCAW. A type of FCAW that relies on the flux materials within a tubular wire electrode to provide shielding for the weld area. FCAW-S does not require external shielding gas.

ferrous metals

A metal that contains iron. Ferrous metals are the most common type of welded materials.

filler metal

Metal deposited into a weld joint to join workpieces and add strength and mass. Filler metal is often provided by consumable electrodes.

filler rods

A unit of filler metal that is manually added to the weld pool by the welder. Filler rods, also known as cut lengths, usually match the composition of the base metal and can add beneficial mechanical properties to the finished joint.

fill-freeze electrodes

An SMAW electrode that has both fast-fill and fast-freeze characteristics. Fill-freeze electrodes both fill a joint relatively quickly and solidify relatively quickly.

flat-position welding

Welding that is performed from the upper side of a joint. In flat-position welding, the face of the weld is horizontal.

flux

A material containing shielding and scavenging elements that is used to protect the weld pool and arc from atmospheric contamination. Flux can be used to coat an electrode, as in shielded metal arc welding (SMAW), contained within the core of an electrode, as in flux-cored arc welding (FCAW), or used on its own, as in submerged arc welding (SAW).

flux-cored arc welding

FCAW. An arc welding process that uses a continuously fed, consumable wire electrode with an inner core of flux. Flux-cored arc welding includes self-shielded flux-cored arc welding (FCAW-S) and gas-shielded flux-cored arc welding (FCAW-G).

gas lens collet body

A specially designed screen assembly that fits inside the cup of a GTAW torch. The gas lens collet body creates a longer, smoother shielding gas flow.

gas metal arc welding

GMAW. An arc welding process in which a consumable wire electrode and shielding gas are fed to the weld through a welding gun. Gas metal arc welding is also sometimes referred to as metal inert gas welding (MIG welding) or metal active gas welding (MAG welding), but these terms are nonstandard in the United States.

gas tungsten arc welding

GTAW. A precise arc welding process that uses a nonconsumable tungsten electrode and inert shielding gas. Gas tungsten arc welding is also known as tungsten inert gas welding (TIG welding).

gas-shielded FCAW

FCAW-G. A type of FCAW that uses a flux-filled, tubular wire electrode and an external shielding gas to protect the weld area. Gas-shielded FCAW electrodes require less flux than self-shielded FCAW electrodes.

globular transfer

GMAW-Globular. A type of metal transfer in which the metal at the end of the electrode melts into a large ball and drops to the workpiece. Globular transfer deposits large amounts of metal into the weld pool.

GMAW

Gas metal arc welding. An arc welding process in which a consumable wire electrode and shielding gas are fed to the weld through a welding gun. GMAW is also sometimes referred to as metal inert gas welding (MIG welding) or metal active gas welding (MAG welding), but these terms are nonstandard in the United States.

GTAW

Gas tungsten arc welding. A precise arc welding process that uses a nonconsumable tungsten electrode and inert shielding gas. GTAW is also known as tungsten inert gas welding (TIG welding).

hardness

A material's ability to resist scratching, abrasion, indentation, or cutting. Hardness generally increases as ductility decreases.

helium

A lightweight, inert gas sometimes used for shielding in arc welding processes. Helium is much lighter than air and can escape the weld area quickly.

hermetically sealed

Air- and water-tight. Hermetically sealed containers are used to protect welding electrodes from moisture.

high-carbon steels

A carbon steel that contains 0.50-1.00% carbon. High-carbon steels are extremely strong and hard, but they always require heat treatment for effective welding.

horizontal-position welding

Welding that is performed on a fillet weld from the upper side of a horizontal surface and against a vertical surface. Horizontal-position welding on groove welds is performed on a horizontal plane with the weld face in a vertical plane.

impact toughness

A material’s ability to absorb energy from a sudden, sharp blow without fracturing. Impact toughness is also known as impact strength.

inert

A substance that does not chemically react with other elements. Inert gases such as argon and helium are used as shielding gas for welding.

inverters

An electrical device that uses transistors to increase the frequency of supplied electricity and convert DC to AC. Inverters allow welding power sources to be smaller and more efficient.

kilopounds per square inch

ksi. A unit of pressure used in the US Customary System that is equal to thousands of pounds per square inch. The unit kilopounds per square inch measures the amount of load pressure that is applied over an area of one square inch to describe the tensile strength of a material.

ksi

Kilopounds per square inch. A unit of pressure used in the US Customary System that is equal to thousands of pounds per square inch. The unit ksi measures the amount of load pressure that is applied over an area of one square inch to describe the tensile strength of a material.

lanthanated electrodes

A tungsten electrode that contains a small percentage of lanthanum. Lanthanated electrodes are typically 1-2% lanthanum.

lanthanum

A rare-earth metal that is soft and ductile and oxidizes slowly. Lanthanum is combined with tungsten to make lanthanated GTAW electrodes.

low-alloy steel

A steel that contains small amounts of intentionally added materials that change the properties of the metal. Low-alloy steels commonly include manganese, molybdenum, and nickel.

low-carbon steel

A carbon steel that contains 0.05-0.15% carbon. Low-carbon steels are generally tough, ductile, and easy to weld.

low-hydrogen electrodes

An SMAW electrode that limits the amount of hydrogen in the weld metal to produce high-quality welds. Low-hydrogen electrodes are ideal for metals that are susceptible to cracking and for welding in awkward positions.

magnesium

A grayish-white, extremely light metal that is brittle and has poor wear resistance. Magnesium can be combined with aluminum to create an alloy with excellent weldability.

manganese

A silver-gray, nonferrous metal that is hard and brittle. Manganese acts as a deoxidizer and increases strength and hardness in a weld.

mechanical properties

A characteristic that describes how a material responds to forces that attempt to compress, stretch, bend, scratch, dent, or break it. Mechanical properties include tensile strength, toughness, ductility, and hardness.

medium-carbon steels

A carbon steel that contains 0.30-0.50% carbon. Medium-carbon steels are strong, hard, and not as easy to weld as low-carbon steels.

metal transfer

The deposition of filler metal into a weld pool. Metal transfer methods include short circuit, globular, axial spray, and pulsed spray transfer.

mild steel

A carbon steel that contains 0.15-0.30% carbon. Mild steels are generally tough, ductile, and easy to weld, but they have slightly lower weldability than low-carbon steels.

molybdenum

A hard, silver-white metal that is strong and corrosion resistant. Molybdenum is often used as an alloying element to improve strength and hardness.

multi-oxide electrodes

A tungsten electrode that contains small percentages of multiple different oxide additives, such as 1.5% lanthanum, 0.8% yttrium, and 0.8% zirconium. Multi-oxide electrodes have long life spans and are resistant to contamination.

nickel

A silver-white, nonferrous metal that is hard but malleable. Nickel is often used as an alloying element to improve strength and corrosion resistance.

nonconsumable electrode

An electrode that only conducts electricity to the arc and does not melt from the heat of the arc generated during welding. GTAW uses a nonconsumable tungsten electrode.

out-of-position welding

Welding that takes place in any position besides the flat or horizontal position. Out-of-position welding includes welding in the vertical and overhead positions.

overhead-position welding

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

oxide additives

A chemical compound of oxygen and one other element that is intentionally added to tungsten to improve the performance of GTAW electrodes. Oxide additives enhance the electrode's emissions to improve arc starting and stability.

pointed

Having a conical shape that comes to a sharp end. Pointed GTAW electrode tips are used for DC welding.

polarity

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

porosity

A discontinuity characterized by the presence of tiny voids in a weld bead, which occurs when gas is trapped in the weld metal. Excessive porosity can weaken a weld.

potassium

A soft, silvery-white metal that is highly reactive, especially with water. Potassium is used in the flux coatings of SMAW electrodes.

pounds per square inch

psi. A unit of pressure used in the US Customary System. The unit pounds per square inch measures the amount of load pressure that is applied over an area of one square inch to describe the tensile strength of a material.

power source

The device that provides the electricity needed to perform arc welding. Power sources can be plugged into wall outlets or use mechanical devices such as motors or generators to produce electricity.

psi

Pounds per square inch. A unit of pressure used in the US Customary System. The unit psi measures the amount of load pressure that is applied over an area of one square inch to describe the tensile strength of a material.

pulsed spray transfer

GMAW-P. A type of metal transfer in which one droplet of metal forms on the end of the electrode at a time. Pulsed spray transfer uses a current that alternates rapidly between two different amperage levels.

pure tungsten electrodes

A GTAW electrode that contains at least 99.5% tungsten. Pure tungsten electrodes are indicated with the color green.

radioactive

Emitting radiation. The thoriated electrodes often used in GTAW are mildly radioactive.

reconditioned

Repaired or restored to the original condition. Welding electrodes can be reconditioned by heating them in a special oven at a specific temperature for a designated length of time.

root opening

The separation between base metals at the root of a joint. The size of the root opening determines how much weld metal is needed to obtain fusion at the root.

rutile

A reddish-brown or black mineral made of titanium dioxide. Rutile is used in the flux coatings of some SMAW electrodes.

scavenging elements

A material that cleanses and purifies the weld pool while it is still in a molten condition. Scavenging elements can help improve the quality of the finished weld.

self-shielded FCAW

FCAW-S. A type of FCAW that relies on the flux materials within a tubular wire electrode to provide shielding for the weld area. Self-shielded FCAW does not require external shielding gas.

shielded metal arc welding

SMAW. An arc welding process that uses a stick-like consumable electrode with a coating of flux. Shielded metal arc welding is also called stick welding or manual welding.

shielding

A substance that protects the weld pool and arc from reacting negatively with the atmosphere. Shielding can be provided by an external supply of gas or by a type of flux material.

shielding gas

A gas that protects the weld pool and arc from atmospheric contamination. Shielding gas is used in GMAW, GTAW, and gas-shielded FCAW.

short circuit transfer

GMAW-S. A type of metal transfer in which the electrode touches the workpiece to produce a short circuit and high current that causes a violent transfer of metal. Short circuit transfer uses low amperages and small electrodes.

silicon

A blue-gray, semi-metallic element that is also a semiconductor. Silicon acts as a deoxidizer and is often present in arc welding electrodes and flux.

single-pass welds

A weld that is formed by running a single weld bead. Single-pass welds often use stringer beads.

slag

A nonmetallic byproduct of flux that floats to the top of the molten weld pool and forms a hardened layer on top of the solidified weld metal. Slag protects cooling metal and is then chipped off.

SMAW

Shielded metal arc welding. An arc welding process that uses a stick-like consumable electrode with a coating of flux. SMAW is also called stick welding or manual welding.

sodium

A soft, silver-white metal that is very reactive. Sodium is used in the flux coatings of SMAW electrodes.

spatter

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

stainless steel

A type of steel that contains 11-30% chromium and exhibits excellent hardness and corrosion resistance. Stainless steel can be welded with many different welding processes.

stick welding

An arc welding process that uses a stick-like consumable electrode with a coating of flux. Stick welding is also called shielded metal arc welding (SMAW) or manual welding.

strength

The ability of a material to resist forces that would otherwise break or deform it. There are different types of strength, including tensile, compressive, and shear strength.

tensile strength

A material's ability to resist forces that attempt to pull it apart or stretch it. Tensile strength is usually expressed in kilopounds per square inch (ksi) or kilopascals (Pa).

thoriated electrodes

A tungsten electrode that contains a small percentage of thorium, which is slightly radioactive. Thoriated electrodes are usually 1% or 2% thorium.

thorium

A silver-white metal that is mildly radioactive. Thorium can be combined with tungsten to make thoriated GTAW electrodes.

transformer

An electrical device that uses mutual induction to transfer electrical energy from one circuit to another without changing the frequency. Transformers are used in welding power sources to provide a usable low-voltage, high-amperage current.

truncated

Having a blunt shape that ends with a flat surface. Truncated GTAW electrode tips are used for both AC and DC welding.

tungsten

A dense, brittle, gray metal that has excellent conductivity and the highest melting point of all pure metals. Tungsten, also known as wolfram, is used to make nonconsumable electrodes for GTAW.

usability designator

A number or letter used to indicate an FCAW electrode’s operating requirements and characteristics in the AWS classification. Usability designator numbers range from 1-14, but 1, 9, and 12 are most common.

vertical-down welding

Welding that progresses downwards along a vertical surface. Vertical-down welding, like vertical-up welding, is more difficult than flat or horizontal welding.

vertical-position welding

Welding that is performed on a vertical surface, moving up or down. Vertical-position welding is more difficult than flat- or horizontal-position welding.

vertical-up welding

Welding that progresses upwards along a vertical surface. Vertical-up welding, like vertical-down welding, is more difficult than flat or horizontal welding.

weld penetration

The depth to which the arc heat melts the joint below the surface of the base metals. Weld penetration is directly affected by the amount of amperage, but electrode diameter can also influence penetration.

weld pool

The small area of molten metal that forms during welding. The cooled weld pool forms the permanent joint.

welding code

A collection of standards that outline practices and regulations to ensure safe welding practices and high-quality welded products. Several different organizations produce welding codes, but the American Welding Society (AWS) codes are most widely recognized.

welding gun

An instrument that conducts electricity, guides the electrode, and, in some cases, releases shielding gas during welding. Welding guns are used in some automatic and semi-automatic welding processes, such as GMAW and FCAW.

welding position

The position in which a welder creates a weld. Welding positions include overhead, vertical, flat, and horizontal.

welding procedure specification

WPS. A written document that contains all the necessary and specific information for creating a qualified weld. A welding procedure specification must be approved and tested before welding can begin.

welding torch

An instrument that generates the arc or flame used for welding. In GTAW, the welding torch holds the electrode, conducts electricity, and releases inert shielding gas.

wolfram

A dense, brittle, gray metal that has excellent conductivity and the highest melting point of all pure metals. Wolfram, also known as tungsten, is used to make nonconsumable electrodes for GTAW.

yttrium

A rare-earth metal that is soft, lustrous, and highly crystalline. Yttrium can be combined with tungsten and other elements to make multi-oxide GTAW electrodes.

zirconiated electrodes

A tungsten electrode that contains a small percentage of zirconium. Zirconiated electrodes are typically 0.3% or 0.8% zirconium and may be used as a replacement for thoriated tungsten.

zirconium

A gray-white metal with a strong resistance to corrosion. Zirconium is combined with tungsten to make zirconiated GTAW electrodes.