Welders Galore

Welders Galore

Welding Terminologies and Definitions

Looking for a quick way to master welding terms? Here is a glossary to understand the most common terms used in welding.

An abrasive is any material or power tool used in fabrication and welding purposes to repair bad welds, assure solid welds, or refine the appearance of a finished weld. They include attachments such as discs, brushes, cut-off wheels, and de-burring tools.


A welding gas used in the oxyacetylene welding process. To make sure there is complete combustion, acetylene is mixed with oxygen. The result is a blue flame that reaches temperatures of up to 3150°C.

Air-Arc Cutting:

Air carbon arc cutting (metal arc gouging) is the process of cutting metal or gouging inferior or old welds using carbon arc. The molten metal is blown away using a blast of compressed air.


A metal alloy is the metal formed from mixing one or more metals with a nonmetal. The process involves melting the parent metals and nonmetals and mixing them. Brass is an alloy of zinc and copper, while cast iron is an alloy of iron and carbon.

Alternating Current:(AC)

An alternating current is a type of current where the electrons switch the direction of flow at regular intervals.


The process of treating an alloy or metal with heat to reduce brittleness and ductility to improve form-ability and machinability. This treatment is usually done to alter its physical properties.

Arc Length:

Arc length (arc gap) is the distance from the tip of the electrode to the material that is being welded (work-piece)

Arc Welding:

A welding process that uses an electric arc to heat and melt metals. The heat of the electric arc is focused on the margins of two metal plates to be welded.

Arc Welding Electrode:
Arc Welding Electrodes

A coated piece of wire is connected to the welder to form an electric arc. Current flows through the electrode to create an arc, which produces a large amount of heat to melt and bond the metal during welding. Different electrodes have different amounts of flux, which determines the application.

Arc Welding Gun:

A welding gun is a piece of equipment that you hold with one hand when welding. It directs current into the electrode, and some have extra functions of supplying the shielding gas to the arc. Welding guns are either manual or automatic. Different types of welding guns include air-cooled MIG guns, water-cooled MIG guns and push-pull welding guns.  

Arc Welding Torch:

A welding torch is like an arc welding gun. It’s used in automatic welding for high-performance. Just like the welding gun, it is used to provide current and shielding gas to the arc. The torch adjusts the flow of shielding gases and guides the flame.

Argon Welding:
Argon Welding

Is a welding process that uses argon gas as the shielding gas. The gas is used in GMAW and GTAW welding processes. Argon gas is an inert gas that is colorless, odorless, and non-toxic

Atomic Hydrogen Welding:

AHW (Atomic Hydrogen Welding) is an arc welding process that heats and melts metals using an arc that is created between two tungsten electrodes. Heat is produced when hydrogen atoms break and recombine. The shielding gas used in this process is hydrogen. AHW is the best welding process for tungsten.


Backfire is the burning back of the torch flame or momentary retrogression into the welding torch tip accompanied by a violent popping sound and extinguishing or re-igniting of the flame at the nozzle.

Backhand Welding:

Backhand welding technique (or rightward or pull welding) is a procedure whereby the welding torch is inclined at an acute angle of between 30 and 45 degrees. While the filler metal is applied behind the welding torch. The welding starts from the left and proceeds to the right and because of how the torch is inclined the welding pool is clearly visible.

Base Metal:

The base metal is the metal or material to be cut, welded, brazed, or soldered.

Bead Weld:

A weld seam or weld bead is the deposited filler material that connects the metals being welded. The shape and how the bead looks depends on the welding process used and how you move the electrode.

Bend Radius:

The radius of curvature on a bent area of a formed part or bend specimen measured on the inside of the bend. The smaller the bend radius, the harder it is to produce a sound bend.


In welding, beveling is the process of preparing a metal surface before welding. It involves cutting a flat angled slope on the edge to prepare the surface for welding.

Bevel Angle:

The bevel angle refers to the angle at which the metal is cut during beveling. This angle determines how visible the welding surface is and impacts the final weld quality. There are different bevel welding symbols depending on the shape of the groove.

Bevel Cutting:

Bevel cutting is the process of cutting an inclined slope on the metal’s edge. The cutting is done to soften and prepare the edges before welding.


Brazing is a welding process like fusion welding that is used to join metals together. Unlike in fusion welding, the filler metal in brazing has a lower melting point than the metal. This means the base metal does not melt. Brazing is commonly used when welding cast iron and copper.


A raised edge or small piece of rough material remaining on the material after cutting, grinding, or machining. A burr leaves the material vulnerable to further damage and must be removed through sanding, grinding, filing, or using a deburring tool to achieve a smooth, safe finish.

Butt Joint:

A butt joint is also known as a butt weld. It consists of two metal pieces placed next to each other on the same plane. A welder applies a continuous weld down the center line to weld the pieces together. A butt joint has no stock overlap but can have a root opening.

Some butt joint examples are:

  • Double bevel
  • Double J
  • Double V
  • Double U grooves
  • Square
  • Single J
  • Single V
  • Single U
  • Single bevel
Cap Pass:

A cap pass is the final pass on a weld joint. It refers to the weld beads that cover the entire joint to protect against contamination and oxidation. It also creates a smooth, aesthetically appealing finish on the weld joint. A cap pass can be a single-pass weld or multiple-pass welds in a capping bead.

Carbon Arc Cutting:

A method of cutting metal using the heat generated by a carbon arc. The process utilizes a graphite or carbon electrode, and the molten metal is removed by blasting it with air.

Chip Test:

A metal identification test in which a cold chisel and hammer are used to chip the metal surface to reveal the color of the base metal. During the test, the ease of chipping and the shape of the broken pieces are observed. If the metal is ductile, the chip will be continuous, while for a brittle metal the chip will be small fragments.

Coated Electrode:

An electrode that has a flux coating that has been applied through painting or spraying.  The coating produces a gas that envelopes the arc when welding to prevent contamination of the weld. Coating of the electrodes are different in the type and thickness they have.


Coalescence is the bonding of two metal pieces by liquefying the places where they are to bond. The two pieces become one continuous solid by coalescing the liquids and allowing them to solidify. If the welding is done properly, the emerging piece is as strong as the original.

Complete Fusion:

All welding requires complete fusion to achieve the proper weld strength. The piece of base metal and filler metal have to fuse at all layers, passes, and surfaces intended to be welded.

Complete Joint Penetration Weld:

A complete joint penetration (CJP) or a full penetration weld is welding in a groove that covers the entire thickness of the metal. The groove for CJP weld is either U, J, or V. This weld is ideal when looking for a joint that can handle high stress. 

Composite Electrode:

An arc composite electrode is a welding electrode that is made with more than one metal. The electrode is either bare or coated.

Constant Current:

Referred to as stationary current or steady current, a constant current is a power source that delivers and maintains a steady current despite changes in voltage. Constant Current welding machines vary their voltage to maintain a steady current. Where as constant voltage (CV) machines do the opposite.

Constricted Arc:

A constricted arc is found in plasma welding where the heat comes from a constricted arc. Plasma is constricted through a fine-bore nozzle and leaves at a very high velocity.

Covered Electrode:

A covered electrode is the type of electrode used in arc welding that has a metal core and a thick covering. The covering protects the molten metal from reacting with elements from the atmosphere.


A crater in welding is a depression or a circular hole that forms on top of a molten paddle when welding. The development of a crater is a sign of a defect, which is usually caused by incorrect termination.

Cutting Attachment:

A cutting attachment fits onto the end of a torch to convert an oxy-fuel welding torch into an oxy-fuel cutting torch. This device allows the welder to use the torch to cut through metal. A cutting attachment consists of a tip to place on the end of the torch and a valve for controlling the flow of fuel gas and oxygen to the tip.


Welding cylinders contain welding gas and are available in different sizes. The most common sizes are 40, 80, and 125 cubic ft. cylinders.

Deposited Metal:

The deposited metal is the additive metal used as filler during welding, soldering, or brazing. It can be in the form of a rod, wire, or powder. The purpose of deposited metal is to join two work-pieces by fusing them at a high temperature.

Deposition Efficiency:

Deposition efficiency refers to the ratio of the amount of filler metal deposited to the amount of filler metal melted, expressed as a percentage. Several things influence deposition efficiency, such as welding technique, welder’s skill level, power source, shielding gas, amperage, and weld bead width.

Deposition Rate:

The speed at which a welding wire melts and is deposited as a weld. It is defined by pounds per hour or kilogram per hour.

Depth of Fusion:

The depth of fusion is the distance that fusion reaches into the base metal or previous pass from the surface that melts during welding.

Direct Current (DC):

Direct current is the opposite of alternating current. It is a type of current that flows in a single direction. DC is produced by power sources such as batteries, generators, and cells.

Direct Current Electrode Negative (DCEN):

This is the direction of current flow, where current flows from the electrode to the work-piece. The electrode connects to the negative terminal, while the work piece is attached to the positive terminal. It’s also known as straight polarity.

Direct Current Electrode Positive (DCEP):

This is the direction of current flow from the work-piece to the electrode. The electrode is connected to the positive terminal, and the work piece is connected to the negative terminal. It’s also known as reverse polarity.

Double Arcing:

Double arcing is a condition in plasma welding whereby the arc flowing through the nozzle results in two arcs. One arc between the work piece and the nozzle and the other one between the nozzle and the cathode.

Downhill Welding:

Downhill welding progresses from the top, downwards. Because downhill welding works towards gravity, it’s faster (hot and fast) and has less distortion. However, this process results in shallower penetration.


Ductility is the ability of a metal to be deformed and manipulated into different shapes. This is either by bending, twisting, or stretching without breaking. 

Duty Cycle:

The duty cycle of a welding machine refers to the percentage of time that a machine can weld continuously before being let to cool down. It’s usually expressed in percentage, in a cycle of 10 minutes. A welding machine with a duty cycle of 60% can weld for 6 minutes continuously.


An electrode is a wire that conducts current to create an arc that generates heat to melt the metals. Welding electrodes are made of different materials including cast iron, mild steel, brass and aluminum. There are consumable and non-consumable electrodes that are used for different welding processes.

Electrode Coating:

Welding electrodes are coated using several chemicals and materials. This coating burns during welding, producing a gas that protects the molten metal from reacting with elements from the atmosphere. The different types of coatings include Titania sodium, Cellulose Potassium, Iron Powder Titania among others.

Electrode Holder:
Welding electrode holder

An electrode holder or stinger is a clamping device that securely holds the welding electrode during welding, allowing the current to pass through. 

Electron-Beam Welding:

Electron beam welding is a welding process that takes place in a vacuum chamber, whereby a welding gun produces electrons. These electrons are then directed at a very high speed onto a work piece using a magnetic field. When these electrons strike the work piece, heat is generated that melts the metals.

Filler Wire:

A filler wire is an alloy or pure metal that is melted during welding to join metals together. For consumable electrodes, the metal serves as the filler metal as well as the electrode by allowing current to pass. The filler wire is either coated or bare.

Flash Welding:

Flash welding is a type of welding where no filler metal is used. To join the metals together, the metals are pressed together. The two ends are fed with a current and since there is a gap between the ends, an arc is formed that melts the ends.

Flat Welding Position:

Flat position welding or downward position is a welding process where the metals being welded are placed flat. Welding is done on the top side horizontally. The molten metal moves downward filling the groove. It’s the easiest to learn and perform.


Also referred to as a cleaning agent or flowing agent, welding flux is the coating applied on welding electrodes. During welding, the flux materials burn to produce gas that covers the molten weld, preventing reaction with the atmosphere. Flux is a mixture of different minerals, chemicals and alloying materials.

Flux Cored Electrodes:

Flux Cored Electrodes are used in flux-cored arc welding. These electrodes are either gas-shielded or self-shielded. Both types feature an outer sheath and are filled with flux.

Forehand Welding:

Forehand welding is a welding technique where the flame or rod is applied before the torch. The electrode points towards the direction of weld progression, and the welder holds the torch at a 30-degree angle from their right side. This position allows the torch to point directly between the welding puddle and the rod.

Fused Fluxes:

Fused fluxes is a type of flux used in submerged arc welding. They are made by mixing the ingredients when they are dry, and then melting and fusing them in a furnace. After cooling, they are crushed into small particles.  

Gas Metal Arc Welding (GMAW):

Gas Metal Arc Welding (GMAW) is a welding process that involves heating metals using an electric arc. The arc is created between a bare consumable electrode and the work piece. To avoid contamination of the weld, a shielding gas is used, in this case, argon.

There are two types of GMAW welding: Metal Inert Gas welding (MIG) and (MAG) Metal Active Gas welding.

Gas Regulator:
Welding Gas Regulator

A gas regulator is a regulating device that regulates the pressure of the gas coming from the gas tank. The regulator maintains a steady gas pressure that meets the welding requirement depending on what is being welded.

Gas Tungsten Arc Welding (GTAW):

Tungsten inert gas (TIG) or Gas Tungsten Arc Welding (GTAW) is a type of welding process that heats and joins metals using an electric arc that is formed between a non-consumable tungsten electrode and the work piece. The weld is protected using argon or helium gas.

Gas Welding:

Also referred to as Oxyacetylene welding, gas welding is a type of welding process that uses a mixture of oxygen and acetylene gas to generate heat that cuts or joins the metals. Gas welding is rare these days.

Hammer Welding:

Hammer welding is an ancient way of welding where metals are heated and then hammered together. It’s similar to forge welding.

Horizontal Welding Position:

The horizontal welding position is a bit similar to the flat welding position but it’s more complicated. In these positions, (2F or 2G) the work piece is held parallel to the body when welding so that the weld axis is horizontal.

Inclined Position:

An inclined position is sloped welding on an incline of a 45° surface. Gravity forces tend to pull the molten matter downward in a horizontal position weld. The welder has to use a short arc to produce proper beads in an inclined position.

Incomplete Fusion:

Incomplete fusion is a welding defect whereby the filler metal and the base don’t fuse properly, hence leaving a gap The major cause of incomplete fusion is improper placement of the welding gun.

Incomplete Joint Penetration:

Incomplete Joint Penetration is a welding defect whereby the molten metal fails to cover or fill the entire thickness, leaving a space. This is mostly formed when the angle design restricts the movement of the molten metal.

Inert Gas:

An inert gas is a chemically non-reactive gas that does not form chemical compounds. These gases include helium, neon, argon, xenon, krypton, and radon. These gases protect the weld from oxygen and contaminants that may degrade the weld.


Kerf is the span of material removed during welding. It is the width of the weld bead, and it depends on the welding process, material being cut, work-piece thickness, lens focal length, and the power source the welder is using.

Lack of Penetration:

Lack of penetration is another situation that leads to a weld defect. It occurs when the root of the bead does not cover the entire thickness, leaving a space.

Lap Joint:

A lap joint is formed when two pieces of metal are placed overlapping each other. Welding is done where the metals intersect on one or both sides. Lap joint is common when joining sheets or plates.

Laser Beam Welding:

Laser Beam Welding is a welding procedure that uses a laser to join materials together. The laser beam provides the heat that melts the materials.


Liquidus is the temperature at which an alloy is completely melted.

Magnetic Pulse Welding:

Magnetic Pulse Welding is a non-contact welding process that uses magnetic force to join materials together. The process is little known and does not require heat.

Melting Point:

The temperature at which solid objects change states from solid to liquid. Pure solids melt at a specific temperature.


Melt-through happens when the weld from one side burns through the base metal and reaches the root. The welder melts the entire base metal thickness. This default is near or on the weld seam and is common on thinner materials or workpieces with low thermal conductivity.

Metal ARC Welding:

Metal ARC Welding (Manual Metal Arc welding or Shielded Metal Arc Welding) is mostly known as stick welding. This process uses a coated consumable electrode that creates an electric arc between the electrode and the work piece.

MIG Welding:
MIG Welding

MIG welding or Gas Metal Arc Welding (GMAW) is a welding process that utilizes a continuous consumable electrode that is continuously fed through a welding gun. The gun also supplies the gas used to protect the weld during welding.

Open-Circuit Voltage (OCV):

Open-Circuit Voltage (OCV) or no-load voltage refers to the voltage that exists between the electrode and the work piece where there is no welding going on. For safety purposes, the highest OCV for welders is 80 volts.

Plasma Arc Gouging:

A plasma arc gouging is a process similar to plasma arc welding. It involves removing metals and blowing them away using a plasma arc, creating a hole or groove.

Plasma Arc Welding:

Plasma arc welding (PAW) is a welding process that uses heat created by a constricted arc. The arc is formed between a non-consumable tungsten electrode and the work piece.

Plug Weld:

Rosette weld or plug weld is a welding process that involves attaching metals using slots or holes similar to how rivet joints work. Several holes are made on one sheet. The sheet with holes is then placed on top of the other sheet, then welding is done.

Positions of Welding:

Welding positions refer to the different ways of joining metals during welding. There are four welding positions flat position, horizontal position, vertical position and overhead position.

Pulsed MIG Welding:

Pulsed MIG welding refers to an advanced MIG welding process whereby the electrode does not touch the puddle. This means it’s spatter-free. A pulse welding machine produces a current that constantly changes from low to high.

Pulsed Power Welding:

Pulsed Power Welding refers to a welding process whereby the welding power source is programmed to produce power that alternates between low and high.

Residual Stress:

Welding residual stress is the inconsistent deformation and internal stress inside the weldment caused by temperature differences in the heating and cooling during the welding process. Residual stress develops due to a weld joint shrinking as it cools. The nearby material pulls back to maintain a connection with the shrinking weld material.

Resistance Welding:

Resistance welding or electric resistance welding (ERW) refers to several welding processes that weld metals by generating heat through electrical resistance. These processes include induction welding, flash welding and spot welding.

Reverse Polarity:

Refers to a configuration whereby the plates are negative and the electrode is positive. In this case, the electrons flow from plates to the electrode. This configuration is faster and ideal when welding thin materials. 

Root Penetration:

Root penetration refers to the distance that molten metal goes into the root face.

Self-Shielded Flux Cored Arc Welding (FCAW-S):

Self-shielded flux-cored arc welding (FCAW-S) refers to a type of FCAW that uses a consumable electrode filled with flux material. When welding, the shielding gas is derived from the flux within the electrode.

Shielded Metal Arc Welding (SMAW):

Shielded Metal Arc Welding (SMAW) or Shielded Metal Arc Welding (SMAW) or stick welding refers to a welding process that uses a flux coated electrode to create an electric arc. The flux material produces gas that protects the weld pool.

Shielding Gas:

Shielding gasses are inert or semi-inert gasses used in gas metal arc welding and gas tungsten arc welding to protect the molten weld pool from atmospheric elements such as oxygen, nitrogen, hydrogen, and water vapor. If these elements react with the weld pool, it can cause excessive spatter, porosity, and cracking.

Short Circuit Gas Metal Arc Welding (GMAW-S):

Also referred to as short arc, Short Circuit Gas Metal Arc Welding (GMAW-S) is a low energy welding process that uses an automatic or semi-automatic machine.

Short-Circuiting Transfer:

Short-Circuiting Transfer is a mode of transfer in MIG welding when using low voltage. The process occurs when there is contact between the wire and the metal creating a short circuit.


Slag is a by-product of some welding processes that form on top and around the welding surface. It typically consists of oxidized materials, contaminants and impurities.


Welding splatter refers to the molten material that splashes away during welding, landing on the base material and surrounding surfaces. Splatter creates a mess and can injure the welder.

Spiral Arc Welding (SAW):

Spiral Arc Welding (SAW) is a type of welding process that is applied in the welding of pipes.

Spoon Gun:

A spoon gun refers to a MIG gun that features a compartment for the spool. It’s used when welding aluminum.

Spot Welding:

Spot welding is a type of resistance welding that welds metals by applying heat and pressure. This process does use a shielding gas or filler metal.

Stringer Bead:

A stringer is a type of welding bead that is formed when you move a SMAW electrode along the joint without making side movement. The bead is straight and narrow.

Submerged Arc Welding (SAW):

Submerged Arc Welding (SAW) refers to a welding process that forms an arc between a bare consumable electrode and the work piece. This process is used in heavy welding projects such as pipe welding, shipbuilding and structural engineering.

Tensile Strength:

Tensile strength refers to the maximum amount of pulling and stretching a metal can withstand before breaking. It’s how much tension the metal can withstand. 

TIG Welding:

Gas Tungsten Arc Welding (GTAW) or Tungsten Inert Gas (TIG) refers to a welding process that welds using a non-consumable tungsten electrode.

Ultimate Tensile Strength:

Ultimate tensile strength (UTS) refers to the maximum amount of force that a metal can withstand when being pulled or stretched before breaking.

Vertical Weld:

Refers to a weld that is done on a vertical surface.


Weldability is the ability of a metal or an alloy to be welded.

Welding Arc:

The process of welding metals using an electric arc to heat and melt the metal.

Welding Joint Type:

Refers to the different joints formed when welding. Examples of welding joints include butt joint, corner joint, lap joint, and T-joint among others.

Welding Rod:

Another name for welding electrode or filler metal.

Weld Pool:

Refers to the molten metal before cooling and solidifying.

Wire Feed Speed:

The speed at which the electrode is combusted in MIG welding.

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