November/December 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 | N O V E M B E R / D E C E M B E R 2 0 1 8 2 0 automakers refused any Cu additions. These stipulations led to development of very lean 6xxx alloys, like Sumitomo’s SG12 and Kobe’s KS 6283. Honda be- came the first company to use 6xxx al- loy for the skins of the 1991 Acura NSX, its all-aluminum supercar. EUROPEAN PROGRESS In Europe, the market was small enough that local producers supplied local manufacturers—British Alumini- um for Land Rover in the U.K. and Alu- suisse for Porsche and other German OEMs in Germany. Seven years after the start of production for Porsche, Alusu- isse finally registered Ac-120 as 6016 in 1984 and began to focus on the au- tomotive market. Production moved from the narrow line at Alusingen to a newly upgraded 2000-mm line at its Sierre Works. There, under the protec- tion of its patent, Alusuisse began its dominance of the European auto body sheet market. Volvo was one of its first volume customers with the liftgate of the 1985 740 Estate model. Due to the absence of an adhesive that could bond aluminum sheet straight from the press shop, Vol- vo installed a part washer followed by a dryer before assembly. After the lift- gate assembly, parts were cured in a pass-through oven then shipped to the body shop at the assembly plant. While the process was nicely automated, it added two costly steps to the normal steel process. GM became the first U.S. manufacturer to use 6016 when Italian coachbuilder Pininfarina specified it for the hood, fenders, and decklid of the 1987 Cadillac Allanté. CONSENSUS BUILDS FOR 6XXX ALLOYS As 1991 drew closer, auto body sheet alloy development had finally started to converge on 6xxx alloys: 6111 in the U.S., Cu-free 6016 in Europe, and similar lean 6xxx alloys in Japan. All took advantage of the E-coat bake ov- ens to deliver a combination of form- ability in the press shop and strength on the final vehicle. Legacy alloys such as 2036 would remain in use for the re- mainder of their production runs. Alloy 2008 was entering production that De- cember for the early launch of the hood inners of the 1992 Ford Crown Victo- ria and Mercury Grand Marquis stable- mates. With sales that would quickly surpass 200,000 per year, it would be- come the highest production volume aluminum hood to date. However, much remained to be done before alu- minum auto body sheet would enter the big leagues. ~AM&P For more information: Laurent Chap- puis, president, Light Metal Consultants LLC, 8600 Church Rd., Grosse Ile, MI 48138, lbchappuis@icloud.com. References 1. N.C. Cochran, et al., Use of Alumi- num in Automobiles−Effect on the Energy Dilemma, SAE Technical Pub- lication 750421, 1975 SAE Congress, Detroit. 2. R.C. Eissinger, N.H. Jewell, and J.L. Livermore, Development and Eval- uation of Aluminum Body Sheet Metal Panels, SAE Ref 770303, 1977 SAE Congress, Detroit. 3. W.A. Anderson, R.D. Blackburn, and B.S. Shabel, Development of Aluminum Alloys for Body Sheet, SAE Technical Publication 740077, 1973 SAE Congress, Detroit. 4. J.W. Evancho and J.G. Kaufmann, New 6XXX Series Alloys for Auto Body Sheet, SAE Technical Publication 770307, 1977 SAE Congress, Detroit. 5. P.E. Fortin, M.J. Bull, and D.M. Moore, An Optimized Aluminum Al- loy (X6111) for Automotive Sheet Applications, SAE Technical Publication 830096, 1983 SAE Congress, Detroit. 6. M.E. Hyland and W.H. Hunt, Jr., US Patent No. 4,784,921, Aluminum Alloy Automotive Material, Nov. 15, 1988. 7. H. Yoshida, Alloy Development for Transportation in Sumitomo Light Metal, Sumitomo Light Metals, Pro- ceedings ICAA12, p 54-61, 2010. 8. T. Sakurai, The Latest Trends in Aluminum Alloy Sheets for Automotive Body Panels, Kobelco Technology Re- view, No. 28, p 22-28, October 2008. 1985 Volvo 740 Estate sporting an aluminum liftgate. 1987 Cadillac Allanté featuring an aluminum hood, decklid, and fenders.