Welding dissimilar metals is a critical aspect of modern manufacturing, offering the potential to create components that leverage the unique properties of different metals. However, this process is fraught with challenges due to the varying physical and chemical properties of the metals involved. Understanding and overcoming these challenges is key to successful welding of dissimilar metals.

The Challenges of Welding Dissimilar Metals

The primary challenge in welding dissimilar metals lies in their differing melting points, thermal conductivities, and coefficients of thermal expansion. These differences can lead to issues such as poor weld quality, thermal cracking, and corrosion susceptibility. Additionally, the formation of brittle intermetallic compounds at the weld joint can compromise the structural integrity of the welded component.

Considerations when Welding Dissimilar Metals:

  • Controlled Heat Input: Managing the heat input during welding is essential to minimise thermal stresses and distortions. Techniques like preheating and controlled cooling can be employed to achieve this. And, MTI can help. Our newest solid-state welding process, Low Force Friction Welding, offers heightened in-process control for biased heating and controlled cooling.
  • Use of Intermediate Materials: In some cases, introducing an intermediate or a buffer material between the dissimilar metals can facilitate a better bond. The intermediate material acts as a transition between the two metals, reducing the formation of harmful intermetallic compounds.
  • Advanced Welding Techniques: Processes like friction welding, laser welding, and electron beam welding offer greater control and precision, making them suitable for welding dissimilar metals. It is important to keep in mind that friction welding has the broadest capability to weld dissimilar metals than any other welding technique, and that certain materials can only be joined using friction welding.

Applications and Advantages Across Various Industries:

  • Automotive: In the automotive industry, welding dissimilar metals is essential for creating lightweight yet strong structures, contributing to improved fuel efficiency and reduced emissions. Commonly welded dissimilar metals in the automotive industry include Copper to Aluminium for battery cables and heat exchangers, and Steel to Inconel for turbochargers and engine valves.
  • Aerospace: The aerospace sector benefits from this capability in manufacturing components that require a combination of lightweight yet high strength. Welding dissimilar metals also allows aerospace companies to save on their buy-to-fly ratios when joining different Titanium alloys to manufacture aero-engine blisks (bladed disks).
  • Energy: In the energy sector, particularly in power plants, welding dissimilar metals is crucial for piping systems that require corrosion resistance and strength at high temperatures. Examples include welding aluminium alloys to nickel-based heat resistance materials for cryogenic applications, and Copper alloys to Copper Tungsten for high voltage applications.

Welding dissimilar metals is a complex yet vital process in modern manufacturing. It requires a deep understanding of metallurgy, precise control over the welding process, and the right choice of materials and techniques. Fortunately, MTI can handle your project from concept to completion with our in-house metallurgical lab, Weld Development programs, and various friction welding processes. As industries continue to innovate and seek enhanced performance and efficiency, the ability to effectively weld dissimilar metals will remain a key skill in the manufacturer’s toolkit, opening up new possibilities in design and functionality.

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