What Is Stud Welding?

A man welding a piece of metal on a welding table.

When researching some of the different welding processes, you may come across stud welding. It’s frequently used by manufacturing companies to install a fastener on a metal object or surface. Because of its similarities to flash welding, though, some people assume that stud welding is just another name for flash welding. Granted, both welding processes don’t require the use of a filler metal, but they aren’t necessarily the same. So, what is stud welding exactly?

Overview of Stud Welding

Stud welding is a welding process that involves the use of an electric arc to join a fastener to a metal object or surface. Whether it’s a rivet, bolt, nut or any other fastener — including threaded or unthreaded fasteners — is can probably be attached to a metal object or surface using stud welding. There are even special fasteners that are designed specifically for stud welding. Weld nuts, for example, have an elongated flange with excess metal that, when exposed to the heat of an electric arc, melt.

Benefits of Stud Welding

Stud welding is useful because it doesn’t require traditional methods to install a fastener on a metal object. Rather than drilling a bolt onto a metal object, for example, a manufacturing company can attach it using an electric arc. As the fastener heats up, some of the surface metal will metal. The fastener can then be manipulated into the right position, after which it’s allowed to cool. Once the fastener, as well as the metal object, cools, the fastener will join to the object.

The 2 Types of Stud Welding

There are two primary types of stud welding: drawn arc and capacitor discharge. In drawn arc stud welding, both the metal object and the fastener are heated using an electric arc. According to Wikipedia, the fastener acts as an electrode so that it’s able to melt and join to a flat plate on the metal object. Drawn arc stud welding requires a very specific polarity. For aluminum, direct-current electrode positive polarity is used. For steel, direct-current electrode negative polarity is used. Regardless, all forms of drawn arc discharge stud welding require heating both the fastener and the metal object.

Capacitor discharge stud welding, on the other hand, differs in the sense that it does not require the use of flux. And since it doesn’t require flux, it’s a faster and more efficient stud welding process. Manufacturing companies can perform capacitor discharge stud welding more quickly than drawn arc stud welding. Statistics show, in fact, that the average weld time for capacitor discharge stud welding is just 1 to 6 milliseconds.

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