Drawn arc stud welding is one of the most important manufacturing operations in large-scale steel and composite construction. From its first key uses in shipbuilding to its common uses today in bridge construction, roadwork, automotive fabrication, and more, drawn arc stud welding has a large role to play in manufacturing industries. Because it is so important to a range of industries, stud welding technicians need to have a deep understanding of what makes a strong weld and why. If you are working with stud welding for any project, Northland Fastening Systems (NFS) has stud welding tools for rent or purchase, studs in a comprehensive range of dimensions, stud welding accessories, and the expertise of its own stud welding technicians—all to help you get the job done correctly and efficiently.
Drawn arc stud welding has a large range of specifications, calibrations, and additional factors to take into account. Without delving into the numbers and precision often needed to provide a strong weld connection, every technician should know the four basic properties involved:
- Surface Preparation: Drawn arc stud welding can vaporize thin layers of contaminants like paint, rust, or oils, but before welding, surfaces should still be prepared correctly to ensure a strong connection. Any thick coatings must be removed as metal-to-metal contact during the weld is critical to generate an arc. If thicker coats cannot be removed, you’ll need a mechanical punch to create a metal-to-metal connection.
- Ferrules: Drawn arc stud welding uses ceramic ferrules around the weld point. These ferrules contain molten metal during the weld to prevent splatter and shield the arc as it is generated. These ferrules also prevent air flow into the weld to control oxidation, and they protect nonmetal materials around the weld point from charring. Ferrules are chipped away from the weld point when the stud and surface material cools.
- Shielding Gases: Inert or semi-inert shielding gases are typically made up of 100% argon or a mixture of argon and helium. These gases protect a drawn arc stud weld point from oxygen and water vapor during the weld. Shielding gases can also be generated with a flux that outputs a semi-inert gas like carbon dioxide when heated in the weld.
- Flash: Every stud weld creates a flashing of molten metal around the connection point. This flashing can be a sign of a good or bad weld depending on its condition. In a drawn arc stud weld, flashing should be within the ferrule containment and show complete fusion around the entire stud. If you were to take a cross section of the weld, that fusion would be around the base of the stud beneath the surface as well.
Drawn arc stud welding is a complicated process that is used in a broad range of applications. To learn more about drawn arc stud welding, contact Northland Fastening Systems (NFS) at (651) 730-7770 or request a quote online.