Welding accessories include products used in conjunction with welding processes. Examples include torches, nozzles, regulators, safety equipment and protective clothing, and sensors.
Welding accessories enhance a welding operation by increasing safety, efficiency, or process feedback. As described in the Welding Equipment Selection Guide, there are a number of different welding processes, each of which may use specific accessories. For example, arc welding may involve process-specific accessories such as ground clamps and electrode feeders, as well as the more general welding curtains, protective clothing, and sensors.
Common equipment related to welding can be grouped into categories, including equipment for safety, protection, and isolation; system components; and workpiece-based enhancements/positioners.
Welding safety equipment protects the welder or bystander from adverse effects. Welding includes several inherent dangers in the event of inadequate protection, including:
Burns, from electric arcs or open flames
Exposure to toxic (i.e., oxide-containing smoke) or explosive (i.e., acetylene) gases
"Arc eye" or flash burns from exposure to the brightness of an arc
In terms of protection for the welder, personal protective equipment (PPE) such as welding helmets/goggles, gloves, and clothing are essential for safe welding. For some welding operations, such as the joining of reactive metals, a glovebox may be employed.
A welding glovebox. An operator places his/her arms into the openings to weld parts within the enclosure.
Image credit: Glove Box Technology
Gloveboxes may be used to isolate the welder from the process and isolate the process from atmospheric contamination. They consist of a fairly large enclosure, constructed using a non-permeable material, with inverted gloves for the purpose of operator interaction with the process within the glovebox. Enclosures designed to limit contamination are usually equipped with a gas recirculation system, so that byproduct gases can be vented away from the welding area. This venting serves two purposes: to protect the operator and to avoid contamination of the welding joint.
Welding booths and curtains are similarly used to isolate welding processes. In contrast to gloveboxes, they typically shield only passersby or those within the general vicinity, not the welder. Curtains and booths protect work areas by reducing the visual intensity of the welding arc or flame and may also serve to discourage people from unwittingly entering the welding area. Curtains are usually tinted and may be transparent or non-transparent, and are installed with grommets and an overhead pole or beam in the same manner as a shower curtain. Welding curtains are typically flame-retardant due to the high heat of the process.
Welding booths and curtains may be combined into one setup. For example, the booth may take the form of a protective cubicle or stall, with the curtain covering the ingress point, as shown in the image at right.
Welding system components perform a specific function in the joining operation or enhance the safety or efficiency of an existing system. Components used depend on the system and welding technique.
Wire feeders are commonly used in arc welding to move wire electrodes into the weld area for fusion with the workpiece. Feeders typically include a power supply, drive rolls, and a gun-style feeder to deliver the wire to the joint. When electric current strikes an arc between the workpiece and the electrode, the latter's metal core melts into the joint as a filler material.
Grounding clamps, which are used in arc welding as well as plasma cutting, electrically ground a workpiece. A clamp, which is typically attached to a wire connected to the arc welder enclosure, is attached to the workpiece to ensure that the piece and nearby metal objects are at the same potential, greatly reducing the risk of electric shock.
Flashback arrestors are used in oxyfuel and other gas welding operations. They consist of an element containing narrow passages extending through wire mesh or metal foam. If a flame from the welding torch backfires into the gas line, the arrestor element's cold surface rapidly cools and extinguishes the flame. Devices containing only the cooling element are known as flame arrestors, while flashback arrestors add a pressure- or temperature-actuated cut-off valve for additional safety.
Torch handles are simply handles for a gas welding torch or gun. They may include integral hose fittings, valves, or regulators to connect and control the supply of oxygen and fuel gas. The torch tip also contains a mixing chamber, where the two gases mix and ignite.
Weld oscillators/weavers (shown at right) are employed in automated MIG and submerged arc welding. They provide side-to-side motion to produce a weave seam. Oscillators typically use slides in conjunction with a control device and power supply to achieve repetitive motion.
Workpiece Automation and Enhancement
While the equipment above integrates with a welding system to enhance the process, other welding accessories apply more directly to the workpiece. Because welding often involves joining a long seam, frequent repositioning of large pipes, tubing, and tanks is necessary. This repositioning may be automated by using a circumferential welder or a rotator.
Circumferential welders are employed when joining cylindrical workpieces such as pipes, tubes, and drums. They consist of a welding apparatus, control system, workpiece holders, and a positioning system comprised of bearings or wheels to turn cylindrical parts. Circumferential welders may have two or more welding heads for simultaneous joining at two different points of the workpiece.
The pipe-turning mechanism on a circumferential welder.
Image credit: Weldlogic
Rotators (or turning rolls) are standalone units similar to a circumferential welder's positioning apparatuses. Turning rolls with widely spaced wheels can be used to turn tanks, while those with close wheels are used to turn pipes.
Weld backing is a ceramic or metal material placed beneath the joint. It imparts numerous benefits to the joining process, including:
Root welding and filling using a single pass
Protection from atmospheric contamination and elimination of defects
Deposition of more weld material
Ability to weld only one side of a joint
Ceramic backings are discarded after welding, but metallic backings are integrated as part of the final joint. All weld backings are manufactured with dimensional profiles specific to a certain weld joint, as shown in the image at right.
Welding accessories may be governed by certain published standards and specifications. Example standards include:
—AWS F2.3M: Specification for use and performance of transparent welding curtains and screens
—BS EN 730-1: Incorporating a flame (flashback) arrestor in gas welding equipment
—ANSI/IEC 60974-5: Arc welding equipment—wire feeders
—BS ISO 17683: Ceramic weld backing for marine use
Glove Box Technology—Welding reactive metals
Lincoln Electric—Grounding and arc welding safety