Stud welding is typically associated with the fastening together of two steel bodies. While this is often the case, welding can also be used with a variety of metals and other nonmetal materials such as plastics. One of the secondary metals used in welding processes is aluminum. In fact, when it comes to welding studs on an aluminum surface material, the right process can create a strong weld that is effective in the long term. If you are working with aluminum in your stud welding process, Northland Fastening Systems (NFS) provides the tools, studs, and expertise you need to get the job done effectively and efficiently.
Welding studs on an aluminum surface can be a more difficult task than working with steel materials, largely because aluminum is a much more conductive metal, both thermally and electrically. A higher conductivity at the weld point draws heat away from the stud, rendering the temperature insufficient to form a strong connection. Without correctly preparing the weld process, welding to aluminum surfaces can be like trying to heat up a cup of coffee during a blizzard.
The best way to achieve a strong stud connection to aluminum is to prepare the surface and correctly calibrate the stud welding process.
- Surface Preparation: Aluminum surfaces can easily build up oxides. For a quality weld, these oxides need to be removed with a stainless steel brush. After brushing off oxides, surfaces should be wiped down with a non-VOC cleaner.
- Weld Speed: Both CD and drawn arc stud welding processes should be done as quickly as possible when working with aluminum. Speed can help limit the unwanted conduction of heat away from the weld. CD weld times, for example, are completed in 10 milliseconds.
- Shielding Gas: If you are using drawn arc stud welding with aluminum, then shielding gas is a requirement. This gas is critical in generating enough heat at the weld point and combating aluminum’s higher conductivity. Most welders use 100% argon shielding gas, but 100% helium or a mixture of helium and argon are also useful in aluminum welding.
- Ceramic Ferrule: Like shielding gas, ceramic ferrules are necessary when drawn arc welding onto an aluminum surface. This ceramic ferrule contains the tip of the welding stud, and more effectively distributes heat and shielding gas around the weld point.
- Stud Design: Another key difference in aluminum welding is the stud design for drawn arc stud welding processes. The best aluminum studs have a built in ignition tip that burns away before the weld is performed. This allows the welding arc to last longer and generate more heat than a typical welding stud would.
To troubleshoot an aluminum stud weld result, examine the connection point and surrounding surface material. If there is a flash ring or if the stud and/or surface are left shiny, the weld was not performed correctly.