Polarity and Current for Weld Fastening Systems

From ship building to composite thru-deck welding, stud welding is a simple operation used in many complex construction projects. The process of stud welding is a relatively new one, with a history dating only back to the turn of the 19th century. The newness of stud welding fastening systems is largely due to its use of electricity as a sole power source and arc generator. Because of this, the polarity and current supplied to a stud welding unit must be perfectly calibrated for the tool, stud, surface material, and weld circumstances.


If you are using stud welding to complete a project, you can rely on Northland Fastening Systems for all your studs, tools, accessories, and service needs. We provide a comprehensive selection of everything needed for stud weld fastening systems and expert technical support to customers worldwide.


If you are working with a stud welding unit and calibrating that tool for the weld you need, it’s important to understand the role of polarity and current for drawn arc and capacitor discharge (CD) welds.



Every electrical current has a polarity that is either positive or negative. There are types of stud welding tools that use either polarity, but choosing which tool and polarity depends on the stud, the welding operation, and the surface material of what you will connect the stud to. Negative-electrode polarities are also referred to as “straight,” and positive-electrode polarities are also called “reverse” polarities. Positive polarities offer a weld with deeper penetration into the surface material. A reverse polarity weld is suitable for heavy-duty welding with larger studs. Negative polarities, on the other hand, offer a quick-melt weld with faster deposition rate, making it ideal for stud pins and rapid construction.



The pattern of electrical currents will also affect the weld results. Currents will move in negative or positive polarities directly or in alternating patterns between the two. Direct current (DC) welding paired with the correct shielding gas offers a smoother, cleaner weld thanks to a stable arc. DC welds also limit splatter in the weld. Because of this, most professionals use DC welding currents with either positive or negative polarities.


In some cases, however, alternating currents are more suitable. Beginners may choose AC welding tools that tend to be less expensive and easier to use. Alternating currents change polarities around 120 times per second with 60 hertz currents. AC welds are also used heavily in shipbuilding because the movement of the ship in construction may cause an arc to blow side-to-side.


Find the Right Fastening System Today

If you are using stud welding as one of your fastening systems in any given project, choosing the right polarity and current type is critical to performing an accurate, clean, and strong weld. To learn more about stud welding specifications or to find everything you need for studs, tools, and accessories, contact Northland Fastening Systems at (651) 730-7770, or request a quote online to get started with us today.