What is Stud Welding?
Although many people believe that there is only one basic welding application, there are actually many different applications involved with welding. One of these areas is the stud welding process, where a bolt or formed nut is welded onto another metal piece. This process may include using stud welding equipment to automatically feed the bolts into the spot welder.
Stud welding, or arc stud welding, involves joining the stud to a flat plate by using the stud as an electrode. The polarity that is chosen for the particular stud welding application will depend on the type of metal that is used. For example, aluminum usually requires direct-current electrode positive, or DCEP; while steel demands direct-current electrode negative, or DCEN.
The weld nuts used in stud (or arc) welding usually have a flange with some type of small nubs that melt during the process in order to form the weld. The necked down, un-threaded part of the weld nuts also help to form the desired weld. Another aspect of this type of welding application is the use of a flux, called a ferrule. A ferrule is a ceramic ring that concentrates the generated heat, preventing oxidation and retaining the melted metal in the desired weld zone.
One particular type of stud welding process is called capacitor-discharge welding, which differs from traditional stud welding in that it does not require flux. The process uses a direct-current arc from the capacitor, and welding time is between a mere 1 and 6 milliseconds. Since welding time is shorter in capacitor-discharge welding, the welder can finish the bonding with little oxidation and no actual need for heat concentration.
What are Weld Studs?
Stud welding systems use weld studs as a part of this efficient application. These studs are between 14 gauge to 3/8″ diameter, can range from 1/4″ to 5″ or more in length, and are discharged from capacitors. The tips on the weld end of the stud have two purposes:
oTiming. The tips act as a timing device that keeps the studs off of the base material that is being welded.
oDisintegration. Weld end tips disintegrate once the trigger is pulled on the welding gun, melting and solidifying the weld onto the base material.
What are Arc Studs?
Arc studs are usually loaded with an aluminum flux ball on the weld end, which helps to promote the welding process. These unique studs are an integral part of stud welding equipment, and they can range from a #8 up to a 1 1/4″ diameter stud.
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