Have you ever wondered if welding dissimilar metals is even possible? As trusted metalworking specialists, we at Cyrious Metal Works know how to achieve strong, functional welds by focusing on preparation and choosing compatible techniques. Learn more about it here.

Why Weld Dissimilar Metals in the First Place?

Most welders understand the inherent danger of combining dissimilar metals. Some materials, for instance, have an electrochemical reaction that leads to galvanic corrosion. Without careful planning, you risk thermal stresses and even structural failures over time.

With that said, this unconventional approach may help you achieve several goals that may be worth the extra effort, including:

• Combining materials to achieve specific mechanical properties
• Reducing overall production costs by using less expensive base metals
• Repairing components made of different metals
• Enhancing resistance to wear, heat, or corrosion
• Optimizing a structure for diverse operational environments

Achieving a Successful Weld With Different Metals

If you want to avoid welding defects, you need to account for the following factors.

Metallurgical Compatibility

You can predict how materials might react when combined by considering their chemical compositions and their properties. Important characteristics include:

• Thermal expansion rate: When materials heat up or cool down, they expand and contract at varying rates. Highly dissimilar thermal expansion rates may increase the welded point’s residual stress and make it more prone to breakage.
• Melting point: Steel won’t melt until temperatures reach 1,370°C (2,498°F), while aluminum only needs 660°C (1,220°F). You would need to modify your technique to fuse the materials smoothly.
• Reactivity: Metals with different anodic and cathodic properties will quickly corrode when combined.

You can determine a base material’s chemistry through spark tests, consulting the original manufacturer, or third-party lab analysis.

Filler Material Selection

Properly welding dissimilar metals with incompatible electrochemical properties may require a transition material that separates them. This buffer will keep noble metals from pulling electrons out of more basic metals.

Welding Techniques

After getting a clearer picture of a metal’s behavior, we recommend adjusting these welding parameters to optimize the end result:

• Heat input: You may need to heat one material ahead of the other to balance melting points.
• Welding points: Experienced welders have discovered a way to combat thermal expansion differences by using shorter welds and tacking the ends, center, and 1/4 points on the heat-affected zone.
• Shielding gas: Some gases can react with the atmosphere and create defects in certain metals, and the solution is to fill your workspace with inert mixtures.

End Environment

What are the finished product’s service conditions? Carbon steel and other forms of unprotected metal, for example, quickly corrode in humid, salt-heavy air. The welded component may need protective coatings or galvanizing treatments.

An aluminum alloy may resist corrosion better, but it lacks the strength needed for some structural applications.

Welding Specialists You Can Trust

When done correctly, welding dissimilar metals fosters innovative design possibilities, enhances product longevity, and reduces costs. If you need help with your project, partner with Cyrious Metal Works.

Call 903-345-1841 today for a free estimate or read our blog post on choosing the right welding technique.