What is stud welding?
Although many people believe that there is only one basic application of welding, there are actually many different applications related to welding. One of these areas is the stud welding process, where a cast bolt or nut is welded to another piece of metal. This process may include the use of stud welding equipment to automatically feed the studs into the spot welder.
Stud welding, or arc stud welding, involves joining the stud to a flat plate using the stud as an electrode. The polarity chosen for the particular stud welding application will depend on the type of metal being used. For example, aluminum typically requires a direct current electrode positive, or DCEP; while steel requires a direct current electrode negative, or DCEN.
Weld nuts used in stud (or arc) welding usually have a flange with some type of small nubs that melt during the process to form the weld. The necked-down, non-threaded portion of the weld nuts also helps to form the desired weld. Another aspect of this type of soldering 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 molten metal in the desired weld area.
A 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 the welding time is between 1 and 6 milliseconds. Since the weld time is shorter in capacitor discharge welding, the welder can finish the joint with little oxidation and no actual need for concentrated heat.
What are weld studs?
Stud welding systems use welded studs as part of this efficient application. These studs range from 14 gauge to 3/8″ in diameter, can be 1/4″ to 5″ or longer in length, and discharge capacitors. The spikes on the soldered end of the stud serve two purposes:
oTime. The tips act as a timing device that keeps the studs out of the base material being welded.
or Disintegration. The tips of the solder ends disintegrate once the welding gun trigger is pulled, melting and solidifying the solder onto the base material.
What are bow posts?
Arc studs are typically loaded with a ball of aluminum flux at the solder end, which helps promote the soldering process. These unique studs are an integral part of stud welding equipment and can range from a #8 stud to a 1 1/4″ diameter stud.
