Lightweighting Automotive Metals

The National Highway Traffic Safety Administration’s Corporate Average Fuel Economy (CAFE) standards and other regulations have automobile manufacturers searching for lighter weight steel grades or alternative lightweight materials such as aluminum and polymer composites. A practice called metal sintering, the use of heat and pressure to fuse metals and alloys together to create a stronger, more lightweight composite material, also is gaining acceptance. (Read Where are Automotive Manufacturing Materials Heading?)

There are many recent developments in automotive metals, but the practice of alloying various materials to create lightweight vehicles is not new. During the Art Deco period of the 1930s and 1940s, an elite selection of cars, created more as works of art rather than for efficiency, were manufactured using lightweight metals, often aluminum, for speed. Some were even designed as racing cars, such as the 1930 Mercedes-Benz SSK which, according to Gear Patrol, “was not just a fine example of art deco influence but an eminently capable racing car that performed and made podium. The supercharged engine with 500 lb-ft of torque rocked the SSK to 120 mph, making it the world’s fastest car in 1930. It went on to win numerous races such as the German Grand Prix and the Mille Miglia.”

Perhaps the most notorious car of the Art Deco era is the1934 Bugatti Type 57 Aérolithe, which was built as an exhibition car for the 1935 Paris Motor Show but vanished a few years later, it’s fate unknown. According to Supercars.net, “Momentum behind the style was structured by a design concept of incorporating Electron, an alloy of magnesium and aluminum from IG Farben of Germany, in the design. Though it is strong, and up to one third the weight of aluminum, it is also highly flammable thus welding was not possible. This meant that each panel had to be riveted into place which posed a particular problem for traditional design. ”

Magnesium alloys are still used to make racing cars today. An Azom.com article explains, “RZ5 alloy is generally used for gearbox casings although MSR/EQ21 alloys are also being used increasingly due to their superior ambient temperature properties or because of increased operating temperatures. RZ5 wheels have been shown to have significantly better performance than Mg-Al-Zn alloy wheels under arduous racing conditions. Due to the high operating temperature of racing engines, WE54 castings have been used for a variety of Formula 1 engine parts and are used for engine components for a limited edition road car. Forged WE54 pistons offer great future potential for motor racing and other applications will exist for other wrought products.”

Each of these metal alloys is refined and processed to have the appropriate properties for specific automotive components. Off-specification metals will fail to perform as expected and can have dangerous consequences. Portable XRF analyzers are indispensible tools for Positive Material Identification (PMI) — the practice of testing materials for their exact chemical composition to ensure that the incoming raw materials and the outgoing finished parts meet engineering requirements. Watch this video to learn how a NASCAR manufacturer uses portable XRF analyzers to measure all metal components of their cars to make sure they are up to design specs.

Editors note: Were you lucky enough to see the Rolling Sculpture: Art Deco Cars from the 1930s and ’40s n exhibit at the North Carolina Museum of Art in Raleigh, NC? Comment below and let us know your favorite. You can also watch a video of the Sculpted in Steel exhibition of these same cars that took place earlier this year at the Museum of Fine Arts in Houston.