May/June_AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A Y / J U N E 2 0 1 8 2 4 GA 0.025”, FULL C.R.O.H. FULL P.&A. >>. The nomenclature of the specifica- tion stands for steel #24 U.S. Standard Gauge, Full Cold Rolled Open Hearth, Full Pickled & Annealed. The U.S. Stan- dard Gauge was the result of U.S. Code 15, which states, “For the purpose of se- curing uniformity, the following is es- tablished as the only standard gauge for sheet and plate iron and steel in the United States of America.” (Mar. 3, 1893, Ch. 221, § 1, 27 Stat. 746). The switch added another 1.5 kg (3.3 lb) to a car that gained more than 100 kg (220 lb) through the addition of desirable cus- tomer features in the middle of a relent- less drive to minimize all costs. Ford was still looking for weight and cost savings, and in 1918, dissat- isfied with Alcoa’s prices, he began to search for a way to produce his own aluminum [8] . His plans were met with strong opposition and he had to aban- don the project, instead starting his own steel company in 1925. Ford was producing sheet steel by 1935. For the 1923 model year, Ford in- troduced the Fordor, the company’s first four-door sedan. It was the most expen- siveModel T, more than double the price of the base model. It also weighed close to 300 kg (661 lb) more than the 1909 roadster. The spaceframe for the body and doors was still wood, but sheeted in aluminum to cope with the increased weight. The roof, like all cars produced at the time, was made of coated fabric. In its first year on the market, Ford pro- duced more than 143,000 Fordors in the U.S. and almost 1400 overseas—a mere 7% of more than 2,000,000 units pro- duced worldwide that year. The next model year saw steel replacing alumi- num on the lower half of the body, and by the 1925 model year, aluminum dis- appeared with cost once again trump- ing weight savings. The Model T’s body construction, sheet metal nailed to an internal wood- en spaceframe, was typical of cars during that period. It allowed a great number of coachbuilders to make bodies for special orders and they of- ten used aluminum sheet, not only to save weight, but because it was proba- bly easier to shape than the sheet steel of the time. The Roaring Twenties be- came the golden days of coachbuilders with names like Antem, American Body, Fleetwood Metal Body, and LeBaron in the U.S. and Castagna, Chapron, Fran- ay, Ghia, Guillore, Kellner, and Zagato in Europe. Each offered custom designs and built aluminum bodies on chas- sis provided by elite car manufactur- ers including Bentley, Cadillac, Daimler, Duesenberg, Isotta Fraschini, Lancia, Lincoln, Marmon, Mercedes-Benz, Pack- ard, Panhard & Levassor, Rolls-Royce, and Stutz. Car manufacturers also turned to aluminum with in-house developments to win at the race track. Bugatti’s alumi- num-bodied 1925 Type 35 dominated Grand Prix competitions for a decade. Later weight regulations further favored extensive use of aluminum, reaching an apex with the German aluminum bod- ies of the Silver Arrows of Auto Union and Mercedes-Benz in the mid-1930s. From the 1920s onward, alumi- num sheet faced increasing compe- tition from steel in the mass market. Body construction was evolving. In the U.S., Edward Budd built the first all- steel car body in 1912. Driven by rising production volumes and cost pressures, carmakers increasingly abandoned wood framing and switched to steel bodies. Steel not only offered advan- tages for both styling and mass pro- duction, it also enabled carmakers to insource body panel production and body assembly, resulting in great cost reductions and improvements in qual- ity. The move drove the development of modern stamping tools and modern joining techniques such as resistance spot welding. The first full steel body appeared in the 1923 Dodge Broth- ers Model 30. In 1925, Armco Steel Co. launched the first continuous hot strip mill, paving the way for steel use in au- tomobile mass production. Ford Motor 1923 Ford Model T Fordor, the company’s first four-door sedan. Auto Union and Mercedes-Benz Silver Arrows in the rain at the Bremgarten circuit in Bern, Switzerland. Circa 1935. Courtesy of mercedes-benz.com .