Lecture 6: Welding Processes

Vocabulary flashcards covering key welding processes, terminology, and defects from Lecture 6: Welding Processes.

Welding

A process that permanently joins two or more parts by coalescence at their faying surfaces.

Faying surfaces

The surfaces of two parts in contact or near contact that are joined in welding.

Solid State Welding

Joining by diffusion under pressure (and sometimes heat) without melting the base metals.

Fusion Welding

Joining by heat that melts the base metals (and often adds filler metal).

Autogenous Weld

A fusion weld made without adding any filler metal.

Filler Metal

Metal added to the weld pool to facilitate bonding and increase joint volume or strength.

Forge Welding (FOW)

Solid-state welding via diffusion under pressure at elevated temperature, joining similar or dissimilar metals.

Friction Welding (FRW)

Solid-state welding where heat is generated by friction with applied pressure to fuse surfaces.

Ultrasonic Welding (USW)

Solid-state welding using high-frequency ultrasonic vibrations under pressure to coalesce surfaces.

Flash

Material expelled from the joint in friction welding due to plastic flow.

Eutectic

A mixture with a unique composition that solidifies at a lower temperature than other compositions.

Heat-Affected Zone (HAZ)

Region of base metal whose microstructure is altered by welding heat but not melted.

Shielding Gas

Gas used to protect the weld from air and prevent oxidation.

Flux

Substance that prevents oxides/contaminants and aids their removal during welding.

Consumable Electrode

Electrode that is melted and becomes part of the weld (provides filler metal).

Non-consumable Electrode

Electrode that is not melted; filler metal is supplied separately if used.

SMAW (Shielded Metal Arc Welding)

Arc welding with a consumable electrode coated with flux for shielding.

GMAW (MIG)

Gas Metal Arc Welding using a continuous bare-wire electrode with shielding gas.

GTAW (TIG)

Gas Tungsten Arc Welding using a non-consumable tungsten electrode with inert gas shielding.

FCAW (Flux-Cored Arc Welding)

Arc welding with a continuous tubular flux-core electrode; can be self- or gas-shielded.

SAW (Submerged Arc Welding)

Arc welding with a continuous bare wire and flux that completely covers the arc.

Oxyfuel Gas Welding (OFW)

Welding with a flame from acetylene burning in oxygen; portable and versatile.

Oxyacetylene Welding (OAW)

OFW using an acetylene-oxygen flame; filler metal may be used and flux-coated rods aid cleanliness.

Spot Welding

Resistance welding that creates a weld at a single location between two electrodes.

Resistance Welding (RW)

Heating of the joint by electrical resistance (I^2R) under pressure.

Resistance Seam Welding (RSEW)

Resistance welding using rotating wheel electrodes to produce a series of overlapping welds along a lap joint.

Porosity

Gas pockets formed in weld metal during solidification due to trapped gases.

Shrinkage Voids

Cavities formed by solidification shrinkage in weld metal.

Slag Inclusions

Nonmetallic slag entrapped in weld metal during solidification.

Incomplete Fusion

Lack of fusion between weld metal and base metal.

Incomplete Penetration

Weld does not fully penetrate the joint thickness.

Butt Joint

A joint where two pieces are joined in a single plane.

Corner Joint

A joint formed at a corner where two pieces meet at a right angle.

Lap Joint

A joint where one piece overlaps another.

Tee Joint

A joint where one member intersects another at a right angle, forming a T.

Edge Joint

A joint formed along the edge of one or both members.

Fillet Weld

A triangular weld filling the interior angle between two surfaces.

Groove Weld

A weld made by preparing a groove in one or both pieces to be joined.

Slag

Nonmetallic byproduct formed on the weld bead in some arc welding processes.

NDT (Non-Destructive Testing)

Techniques to evaluate weld quality without damaging the part.

Penetration

Depth to which weld metal fuses into the joint; relates to complete penetration.

Spatter

Small droplets of molten metal expelled during welding.

Weld Pool

The pool of molten metal formed at the weld site.