Welding Fasteners: Where to Buy & How To Use?

Different types of welding fasteners are arranged for display.




Welding is often a top choice for installing secure and permanent connections. But how does welding relate to fasteners?

Welding Fasteners are specifically designed to be welded, whether that is on an automobile production line or in a small shop setting. If you are still in the design stage for your project, consider these advantages of welding fasteners:

  1. With the correct settings welding fasteners offer the potential for a clean presentation, as the strong connection points are mostly between the base material and fastener.
  2. Proper welds are stronger than the surrounding material. Stress testing your welded fasteners allows you to find which settings give you the best durability and the cleanest installation.
  3. Once you’re dialed in, welding shows its true value in high production scenarios with superior speed and repeatability.


What are welding fasteners?

Welding fasteners come in various shapes and sizes, but some of the most useful and versatile are the Hex Welding NutRetaining Weld Nut, and the Round-Base Spot Weld T-Nut. These three types of welded fasteners can be easily and quickly welded in a fixed location to allow for a solid threaded connection while requiring minimal tooling for assembly. These fasteners are fixed to the base metal in seconds using readily available welding equipment and standard techniques. Once set in place, additional assembly is accomplished with increased speed and efficiency.


Spot welds are made in an automobile factory assembly line.

One significant advantage of welding fasteners is the ability to fix them in a location that may be inaccessible to standard tooling. For example, the automotive industry often uses Hex Welding Nuts and Retaining Weld Nuts on the body-to-frame connection points. In this case, the threaded nut is inaccessible once the body of the automobile is placed on the frame and thus cannot be tightened using wrenches. However, with a preinstalled welded fastener, technicians can simply tighten the bolts from one side of the body, and the job is complete in a matter of seconds.  

The Round-Base Spot Weld T-Nut is a unique solution for assemblies in which the base material is too thin to be tapped for a threaded connection. Threaded connections depend on proper thread engagement, so tapped holes in thin materials, such as sheet metal and thin wall tubing, can be quickly stripped. Installing a Round-Base Spot Weld T-Nut into thinner parent material provides a full depth threaded connection, which is otherwise impossible. These welding fasteners are invaluable for projects in which weight savings is a top priority, and therefore material thickness is shaved down as much as possible. Whether trying to gain an edge by lightening a race car or reducing the shipping weight of a flat pack outdoor furniture set, the Round-Base Spot Weld T-Nut lends itself to the assembly of reduced thickness steel parts.

One benefit of the Retaining Weld Nut is that it has a small amount of play, allowing for slight misalignments. Hex Welding Nuts and Round-Base Spot Weld T-Nuts, however, do not allow for any misalignment, so extra care should be taken to ensure the location is correct and the nut is not welded in at an off angle.  

Pre-Installation Considerations

Several considerations must be made before deciding to use welding fasteners.

Material selection is limited once the decision is made to use welding fasteners. Primarily available in mild and stainless steel, the base material of the part must be compatible with a welded connection. For example, a mild or stainless steel weld nut cannot be successfully welded to a dissimilar metal such as aluminum or titanium. Therefore, the material selection of the weld nut should be matched to the base material using standard welding practices. Rivet Nuts may be a better solution if a fixed threaded fastener is needed in a material aside from mild or stainless steel.

If care is not taken during installation, weld spatter may end up on the threads, rendering the weld nut ineffective. In this case, the fastener may need to be replaced. For this reason, spot resistance welding and projection resistance welding are often the preferred assembly methods, though spatter is still a concern. Keep a thread chaser on hand to verify the threads in the fastener are clean after welding is completed. Once welded, these fasteners are more or less permanent, so properly locating them before welding is critical. 

A nut is welded to a base material using projection welding.
Projection welding in action: embossed projections on the bottom of the nut allow for simultaneous welds at multiple points.


Proper order of operations is vital when planning the use of welding fasteners. These welded nuts are often used in applications where the nut is inaccessible during final assembly. Thus, care must be taken to install the fasteners prior to any access restriction. Additionally, welded fasteners should be installed on bare metal, so proper planning should include applying any paint or finish after the fasteners are installed.

Key Take Away

Welding fasteners are invaluable in many applications. Proper assembly planning and installation are critical to successfully using welded fasteners. Welding fasteners can add the needed thread engagement for threaded connections into thin parent materials. In the proper application, welded fasteners add efficiency for the manufacturer as well as the end consumer.