In this MTI Whiteboard Wednesdays video, we break down bi-metallic friction welding and explain how friction welding can join dissimilar metals that are often difficult—or even impossible—to join with traditional welding methods.
You’ll learn how the solid-state joining process supports stronger, repeatable joints, and where bi-metallic applications can create new opportunities in manufacturing.
For more on one of MTI’s advanced solid-state joining technologies, explore our Friction Welding technology page.
One of the key differentiators between friction welding and other welding techniques is the ability to join two dissimilar metals—two different materials that may not be able to be joined by other techniques. Typically, we can use any of the friction welding technologies to accomplish this.
One example is this linear friction-welded heat plate, where we have copper joined to aluminum. We want the heat transfer properties of copper, but copper doesn’t mount to other surfaces very well or very rigidly. So we weld it to the aluminum, so the aluminum can be used as a mounting surface.
For electrical conductivity, we can use two different types of copper. You have a softer copper alloy, which is much less expensive, welded to a harder copper alloy. And you only put that hard copper alloy where you need it, where there’s going to be weld characteristics.
Another example might be a submersible motor pump where you have a bi-metallic motor shaft. You need the magnetic properties of a carbon steel, but you need the corrosion-resistant properties of a stainless steel.
Another example might be a bi-metallic motor or engine valve where you have a wear-resistant alloy and a heat-resistant alloy that are welded together.
Another application for welding bi-metallics would be transition joints for rockets, where it’s absolutely critical that you need a leak-proof joint between two different materials. Instead of making a mechanical joint, you can use friction welding even for materials like aluminum and Inconel.
Another application, these end up being two different steels, a gear steel and a more standard steel. Here, you don’t want to manufacture this part as an assembly. It’s much easier to cut the gear teeth before welding, weld the two different materials together, as opposed to trying to machine this gear out of an assembly.
Friction welding of bi-metallics allows me to put the expensive material only where I need it, so I can make a cost-effective, high-performance part.
Thank you for joining us for this episode of MTI’s Whiteboard Wednesdays. To see more examples of bi-metallic parts that have been friction-welded, please visit our website at mtiwelding.com