Welding glossary

There are many technical terms used for welding. The following table lists basic welding terms. There may be other terms specific to individual welding methods.

Term Description
Base material Material to be welded in a process where a filler material is used. When a filler material is not used, it is called "weld material."
Bead The elevation of the joint surface consisting of finished weld.
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Beam scan welding A method in which laser beam is applied to the welding point using a polarized mirror. The term “beam scan welding” comes from how the laser beam tracks across (“scans”) a fixed base material.
Butt welding A welding technique that makes the surfaces of the weld joint and base material almost flush with each other.
Filler material A wire or a welding rod used to join the base materials.
Fillet A weld joint with a triangular cross section that joins two surfaces together at approximately 90 degrees.
Flux Material used for cleaning and activating the surface of the base material and improving the fluidity of the filler material.
Fume Solid particles formed when a solid vaporizes once and then condenses through rapid cooling.
Groove A beveled opening created in a weld joint before welding to achieve necessary penetration.
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Heat-affected zone (HAZ) The area of the base material that is not melted but whose microstructure and properties are changed due to heat during welding.
Ionizing voltage The voltage at which the outermost orbital electrons in an atom become ionized (sent outside the atom).
Joule heat Heat generated inside a conductor by electrical resistance when an electric current flows through the conductor.
Manipulator A robot that operates with a multi-joint structure and a servo motor. The movable range varies depending on the number of joints (axes). It can be used for various operations through the replacement of hand pieces attached to the end.
Pass One welding progression made along a weld joint.
Penetration The distance between the top of the base material melted by welding and the original surface of the base material.
Plasma (laser-induced plume) A gas containing charged particles generated by ionization.
Shielding gas Gas used to block out atmosphere in order to prevent the oxidization or nitriding of molten metal during welding.
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Slag Non-metallic substances that form on the weld. The molten slag remaining inside weld metal is called slag inclusion and is a welding defect.
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Spatter The scattering of slag or metal droplets during welding which typically degrades welding quality.
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Tailored blank (TB) Material for press working created through the welding of combinations of multiple steel sheets with different materials and properties to enhance strength and anticorrosion properties.
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Weaving A welding motion typically used for arc welding that moves the torch from side-to-side almost perpendicular to the weld line.
This motion can deposit more weld metal with fewer passes.
Welding defect A defect resulting from abnormal welding caused by the inclusion of weld metal, inappropriate welding technique or welding parameters.
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Weld joint A joint between base materials.
Weld line A line representing a bead or a weld.
A line to be welded, a line being welded or a welded line.
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Weld pool A puddle of molten metal created after the electrode or base material is melted by arc heat or other causes during welding.