Filler alloys and consumables are products frequently used to assemble metal components during welding, brazing, soldering, hard facing, and other thermal processes. They assist in ensuring a longer lasting, more stable cohesion between base metals.
Images credits: USA Weld; The Fabricator; Laco
Also called a filler metal, these items are metallic in nature and are chosen based upon their ability to flow across the base metals; ability to adjoin the base metals; and the temperature at which they melt, which must be below that of the base metal. Frequently, fillers are made of more than one metal to achieve the correct level of viscosity to adequately seal tolerances between the substrates. All metal assemblies must be close-fitting before the thermal process, but components with a relatively large gap will benefit from a filler alloy where only a portion of the material is molten at a given temperature. In contrast, parts with small tolerances are best served by metals and alloys that liquefy uniformly.
Filler metals and alloys come in many forms, including powders, preforms, pastes, foils, tapes, and rod/wire.
Braze and Brazing Alloys
Brazing is a thermal cohesion process that is used to conjoin base metals that may contain toxic components, dissimilar or brittle compounds, extensive liquation, porosity, or residual stress. Brazing may also be suitable for creating electrical contacts or conjoining ceramic components.
Metal alloys best suited for soldering have low melting points and are available in wire, powder, preform, or paste formats. Fusion of solder with the substrate base metal is infrequent. Solder is most often used to create electrical connections, which requires a flux (a consumable) to remove impurities from points of electrical contact.
Welding alloys are used to melt and fuse pieces of a metal assembly together. Welding fillers are usually similar in composition to the base metals. Welding requires a higher temperature than those required for soldering and brazing, and it also directly melts the base metal, a characteristic also unique to welding.
Consumables are products used in the metal joining process to enhance the cohesion between base metals. They do not become a part of the joint or assembly. They are either expended during the process, or are replaced by the user once the item is no longer useful.
These chemical agents are used for cleaning, purification, and improving flow. Fluxes dissolve oxides on the base metal and act as barrier to prevent further oxidation. It also promotes surface wetting and reduces surface tension.
Resistance Welding Electrodes
These electrodes are used to clamp workpieces together and then route electricity in a resistance welding unit. The electrodes are highly conductive alloys and are resistant to arc erosion and deformation at high temperatures.
GTAW and Plasma Arc Welding Electrodes
As part of the welding gun, the arc forms between the electrode and the work surface. Electrodes are usually made of tungsten due to its temperature resistance.