Frank Wilson
Senior Editor
Welding, like any specialty, has its own unique terminology. The top welding terms include those related to welding processes, welding materials, and industry jargon. To better understand welding, it’s worth discussing some of the standard definitions in this field, so here’s a glossary of common welding terminology.
Basic Welding Terms
These are general terms that apply to equipment, metallurgical states or processes, and types of welding.
Alloy
An alloy is either a combination of metals or a metal combined with one or more elements. Metals are often combined to increase their mechanical properties, such as tensile strength, ductility, machinability, etc.
Base Metal
The metal that you intend to weld or cut, as distinct from the filler material.
Electrode
The electrode is the part that conducts the electric current. It can be made from various materials, from tungsten to graphite, and can take the form of a solid rod or a wire fed from a spool. Electrodes can be consumable or non-consumable.
Electrode Holder
A clamping device that you use to hold the electrode. The holder connects to the welding cable and conducts electric current to the electrode. Electrode holders are available in insulated and non-insulated variants.
Filler
Unless the welding process you use melts the metal workpieces directly, fusing them in the process, you’ll probably use a filler material. This is a metal that you melt, creating a molten pool of matter. When the filler cools and solidifies, it creates a welding joint that bonds the workpieces together.
Fillet
You apply this type of weld to two pieces of metal that are perpendicular to each other. A common example is a tee joint, where you weld a vertical bar or plate to one on the horizontal plane.
Fusion
Fusion occurs when the edges of the base metal that you intend to join mix thoroughly. This may also refer to the mixture of the base metal and the filler material. For a welding joint to be achieved, the metal must undergo fusion.
Liquidus
The lowest temperature that metal remains liquid.
Melting Point
This describes the temperature that metal needs to reach or that you need to heat it to before it melts. Aluminum, for example, has a melting point of approx. 1,220 °F, whereas titanium’s melting point exceeds 3,000 °F. Steel alloys typically melt somewhere between 2,500 and 2,800 °F.
Solidus
The highest temperature that metal remains solid.
Welding torch
This is the tool you use in oxy-fuel or gas welding to control the oxygen–fuel mixture flow.
Welding Processes
There are several welding processes, each with its strengths, weaknesses, or appropriate applications. Some are only suitable for certain types of metals. Golden rule in welding is to abide to safety rules to ensure your wellness and of the people around you.
Arc welding
A category of welding processes whereby you achieve fusion by heating the workpiece with an electric arc instead of gas welding.
Electron Beam (EBW)
In Electron-Beam welding, you bombard the workpiece with high-velocity electrons. The impact transforms the electrons’ kinetic energy into heat, melting the workpiece and fusing the metals.
MIG (GMAW)
Metal Inert Gas (MIG) welding, also known as Gas Metal Arc welding (GMAW). This process uses a consumable electrode wire fed from a spool through the welding gun, forming an arc between the electrode and the workpiece.
Oxyacetylene
Also called oxy-fuel welding and gas welding, this is one of the oldest welding processes. Unlike modern arc welding, oxyacetylene relies on a mixture of oxygen and fuel gas, such as acetylene, to melt base metals. In addition to welding, it can also be used to cut steel and other metals.
Plasma (PAW)
Plasma Arc welding (PAW) is a process similar to TIG. PAW forms an arc between a tungsten electrode and the workpiece, which melts the metals. Unlike TIG, however, PAW forces plasma through a nozzle, focusing heat and generating temperatures approaching 10 times those of TIG.
If you're interested in getting plasma cutters, check out our definitive buying guide here.
Spot welding
A type of rapid electrical resistance welding, spot welding uses metal electrodes to focus heat on a spot while also clamping sheet-metal parts together. This process is used extensively alongside stamping.
Stick (SMAW)
Stick or Shielded Metal Arc welding (SMAW) is fast and portable, and the flux that envelopes the rod provides the necessary atmospheric shielding. As a result, you don’t need additional inert gas sources, such as argon or helium cylinders.
TIG (GTAW)
Tungsten Inert Gas (TIG) welding, also known as Gas Tungsten Arc welding (GTAW). This process forms an arc between a non-consumable tungsten electrode and the workpiece. It’s clean but costly and challenging to master. You must supply your shielding gas separately from a cylinder.
Welding Materials
Welding requires the use of a wide variety of metals, gases, and other materials. As a result, the top welding terms you must know include the following:
Acetylene
A highly combustible and odorless hydrocarbon gas, acetylene is combined with oxygen in oxyacetylene or oxy-fuel welding. This is also called gas welding.
Argon
An inert gas, argon is used as a shielding gas in TIG welding to prevent atmospheric contamination of the weld joint.
Flux
Flux is a material that is applied to the workpiece to shield it against atmospheric contamination and oxidation. It achieves other purposes too, such as improving wetting.
Nonferrous
A metallurgical term referring to metals that do not contain iron. Examples include aluminum, brass, copper, lead, and titanium. The opposite of a nonferrous metal includes steel alloys.
Helium
Welders sometimes use helium as an alternative to argon in gas tungsten arc welding. When this is done, it becomes heliarc welding.
Welder Clothing and Equipment
The welder must wear special clothing and equipment to protect against infrared (IR) and ultraviolet (UV) radiation, errant sparks, filler material, and other hazards. The heat generated by welding processes can exceed the surface of the sun.
Goggles
Dedicated welding goggles, ideally with side shields, are a necessary component of welding PPE. Welding produces intense IR and UV radiation, which can cause damage to your eyes if they’re not protected.
Helmet
A welding helmet protects your face and head against burns and other injuries caused by intense heat, metal sparks, and other hazards related to welding. The UV radiation produced by arc welding isn’t only dangerous to your eyes — it can cause sunburn-like injuries to your skin.
Why Knowledge of These Terms is Important
A thorough understanding of the terminology related to welding can help you understand the processes, materials, and equipment needed and give you a head start should you decide to pursue welding as a career.
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Final Thoughts
As a skilled trade and one necessary for the production of many industrial, military, and commercial products, welding is an in-demand job.
