Rex-Cut Blog

    Welding Aluminum and Steel: A Mixed Metal Solution

    How does it sound to build a new component with the strength and manufacturing ease of steel along with the lightweight versatility and affordability of aluminum?

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    Innovations in welding technology are making this dream of aluminum-to-steel joining a reality for automakers around the globe and pose new opportunities for manufacturers looking to stay ahead of the curve in lightweighting.

    Spot Welding

    Shaving pounds off a vehicle can increase its speed, performance, and safety. Driven by the trend of lightweighting vehicles, GM developed an aluminum-to-steel spot welding tip that has the potential to eliminate up to 10 lb of rivets and change industry standards. With eyes on the future, GM’s spot welding technique is slated to replace all the weighty rivets joining the steel reinforcements to the interior aluminum in vehicle hoods.

    The specialty electrode designed for the patented welding tip solves the problem of bonding two very different metals. Oxide buildup is prevented on the aluminum surface, and brittleness is avoided allowing for a superior weld strength.

    This shift in production technology traditionally parallels a need for costly retooling. Yet, GM’s steel-aluminum spot welding technique used the same robots that worked on steel panels and saved the company billions. As technologies continue to develop and shift, finding tools and techniques that can be successfully implemented on multiple materials will be key.

    Beyond Crimping and Bonding

    Looking to hybridize the safety of steel with low-weight aluminum, BMW revealed its version of a steel-aluminum weld on the 7 and 5 Series. Reducing the amount of aluminum that was previously crimped and bonded and incorporating steel sheet with laser welds removed more than 10 pounds of extra weight from the vehicle doors.

    Mixed materials designs pose challenges for production. The differences in thermal expansion between steel and aluminum and the high likelihood of galvanic corrosion require consideration and proper technological solutions. In order to innovate in lightweighting vehicles and save money with new cost-efficient manufacturing, automotive manufacturers need to stay up to date on the rise of aluminum-to-steel joinery while investing in versatile tools for producing and finishing the aluminum-steel seams. Cost saving, long lasting tools like the durable wheel can tackle both steel and aluminum while saving time and labor. 

    Adding Friction

    Pushing beyond the boundaries of a direct heat source, friction stir welding is the newest technology to bond dissimilar metals. Metals as shear force between parts produces heat. One workpiece is spun around at a very high speed and is pushed against the second piece. Force and friction work together at the point of contact to create an ideal temperature to bond the metals. The weld is without flux, filler, or shielding gas. Aluminum, steel, and other lightweight metals are friction stir welded to create top quality joints. Half shafts, axle cases, steering columns and more are being friction stir welded.

    Joining remains the most important fabrication process in automotive technology. Welding innovations for hybrid metal designs have introduced new opportunities and solutions across the industry and the shift toward steel-to-aluminum parts is likely to be groundbreaking for the automotive industry.

    Stay up to date on automotive technology innovations and find the tools to keep your shop efficient as the industry drives toward a future in aluminum. Download our Guide to Aluminum.

    DOWNLOAD ALUMINUM GUIDE NOW

    Filed under: automotive, Aluminum