Not all of the aluminums used by different automakers are the same

Note from Aaron Schulenburg, Executive Director, Society of Collision Repair Specialists (SCRS)

“I asked John Yoswick if I could share this with you all because I think there is a really important fact that was captured here. It is one of the best documented facts of why just because one automaker approves of a tool, or an operation, does not mean it is equally applicable to another automaker. This is a great statement that I hope all of the industry sees and understands.”

KEY DIFFERENCES IN ALUMINUMS: During the Society of Collision Repair Specialists’ “OEM Collision Repair Technology Summit” last month(CRASH 11/30/15), Doug Richman of Kaiser Aluminum cautioned that not all of the aluminums used by different automakers are the same, and they will act differently during repairs. “The bad news is there’s no way folks in your business can tell which version of aluminum you’re looking at,” he said. “There’s no visual distinguishing characteristics you can [use to] determine what the alloy is and what the temper is. But the variations will have a different impact in how you approach the repair. The solution is: We all need to be sure we’re paying attention to the OEM guidelines for the repair of a specific model. They know for each part what the alloy was, what the temper was and how it needs to be handled.” He said most of the aluminums being used are a “T4” temper, for example, which is lower-strength and thus can be formed into complex shapes in the manufacturing process. But some manufacturers, primarily European automakers of higher-end vehicles, then put vehicles through an age (or bake) cycle that raises the aluminum to a “T6” temper which is at least 50 percent stronger than “T4.” This allows them to maximize weight reductions by using even thinner grades of aluminum than, say, that used on the F-150, while still being strong and damage-resistant. Heat from welding can significantly reduce the tensile strength of aluminum, which is why some automakers require the use of specific welders and why OEM procedures often call for use of a backing plate when joining to restore the full strength of that area of the vehicle.

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