Welding is the process of joining two pieces of metal together by hammering, pressure or fusion. Filler metal may or may not be used.

The thickness of the filler material is much greater than the capillary dimensions encountered in brazing. The filler material has a melting point approximately the same or below that of the base metals, but always above 427 C.

As Welded

The condition of weld metal, welded joints, and weldments after welding and prior to any subsequent thermal, mechanical, or chemical treatments.

Axis of a Weld

A line through the length of a weld, perpendicular to a cross section at its centre of gravity.

Back Weld

A weld deposited at the back of a single groove weld.

Backhand Welding

A welding technique in which the flame is directed towards the completed weld.

Backing Strip

A piece of material used to retain molten metal at the root of the weld and/or increase the thermal capacity of the joint so as to prevent excessive warping of the base metal.

Backing Weld

A weld bead applied to the root of a single groove joint to assure complete root penetration.


A sequence in which weld bead increments are deposited in a direction opposite to the direction of progress.

Carbonizing Flame

An oxyacetylene flame in which there is an excess of acetylene. Also called excess acetylene or reducing flame.

Face of Weld

The exposed surface of the weld.

Oxyacetylene Welding

A welding process in which the required temperature is attained by flames obtained from the combustion of acetylene with oxygen.

Oxidizing Flame

An oxyacetylene flame in which there is an excess of oxygen. The unburned excess tends to oxidize the weld metal.

Tack Weld

A weld made to hold parts in proper alignment until the final welds are made.

Weld Bead

A weld deposit resulting from a pass.

Weld Gauge

A device designed for checking the shape and size of welds.

Weld Metal

That portion of a weld that has been melted during welding.

Weld Symbol

A picture used to indicate the desired type of weld.


The capacity of a material to form a strong bond of adherence under pressure or when solidifying from a liquid.

Welder Certification

Certification in writing that a welder has produced welds meeting prescribed standards.

Welder Performance Qualification

The demonstration of a welder's ability to produce welds meeting prescribed standards.

Welding Leads

  1. Electrode lead. The electrical conductor between the source of the arc welding current and the electrode holder.
  2. Work lead. The electrical conductor between the source of the arc welding current and the workpiece.

Welding Pressure

The pressure exerted during the welding operation on the parts being welded.

Welding Procedure

The detailed methods and practices including all joint welding procedures involved in the production of a weldment.

Welding Rod

Filler metal in wire or rod form, used in gas welding and brazing processes and in those arc welding processes in which the electrode does not provide the filler metal.

Welding Symbol

The assembled symbol consists of the following eight elements, or such of these as are necessary: reference line, arrow, basic weld symbols, dimension and other data, supplementary symbols, finish symbols, tail, specification, process, or other references.

Welding Technique

The details of a manual, machine, or semiautomatic welding operation which, within the limitations of the prescribed joint welding procedure, are controlled by the welder or welding operator.

Welding Tip

The tip of a gas torch especially adapted to welding.

Welding Torch

A device used in gas welding and torch brazing for mixing and controlling the flow of gases.

Welding Transformer

A device for providing current of the desired voltage.


An assembly whose component parts are formed by welding.

See also: American Welding Society, Arc Welding, Brazing, Butt Welding, Electron Beam Welding, Forge Welding, Gas Metal Arc Welding, Gas Pocket, Gas Welding, Hammer Welding, Metal Inert Gas Welding, Pressure Welding, Resistance Welding, Tungsten Inert Gas Welding, Weld.

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Subjects: Mechanical Engineering

American Welding Society The mission of the American Welding Society is to advance the science, technology and application of welding and allied joining and cutting processes, including brazing, soldering and thermal spraying.
Welding Design and Fabrication New technologies, improved processes and best practices in automation, gases, welding, safety and regulation.