April 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 | A P R I L 2 0 1 9 2 2 between the proposed aluminum struc- tural system and steel in a production vehicle. Because they would be using production tooling, they simply sub- stituted aluminum gauge for gauge for steel. The structural performance was achieved by increasing the effec- tive thickness through local doublers or simply bonding two entire parts to- gether where finite element analysis in- dicated a weakness. Some small steel brackets were E-coated. Alcan had installed the first pro- totype pretreatment line at its Falkirk plant in Scotland in time for the build, but program timing constraints limited its use to the highest volume thickness (0.9 mm.) Other gauges were supported by batch processes using local shops, as it was done for ECV3. The build focused on the body in white (BIW), with steel production parts for the hood, fend- ers, doors, and liftgate. 5251-O was the sole alloy, and parts were made in the production tooling during production breaks. To compensate for the forma- bility difference, they used prototype methods and lubricants when neces- sary. The parts were cleaned before as- sembly and the BIWs were cured in a paint oven. The build finished in early 1986, and the five rolling vehicles and the single BIW underwent testing with British Leyland. The prototypes successfully passed the durability protocols of BL, opening the door for the next phase of the project—industrialization of the sheet production concept, now named aluminum structured vehicle technology (ASVT). Some new pilot production ca- pability was urgently needed because Alcan and Gaydon Technology were now actively promoting their concept to multiple car manufacturers and the pretreatment spray system installed at Falkirk had proved inadequate. The next version was installed at Alcan’s Bresso plant near Milan, which would produce the material for the next proto- type builds using metal supplied by Al- can Deutschland. The next build partner was found within David Kewley’s contacts from the Joint European Research Consor- tium, of which BL was a member. It- aly’s Bertone was not only a famous automotive design house—it also pro- duced low-volume specialty models for various automakers, like the X1/9 for Fiat and the Volvo 780 Coupe (1985- 1990 model years). When Fiat decided to cancel the X1/9 in 1982, Bertone se- cured the rights to the project and it continued production until 1989, with the car now marketed as the Bertone X1/9. ALCAN AND BERTONE For Alcan, it was a perfect set- up: Bertone was a flexible low-volume production operation, simultaneously capable of high quality engineering and prototype work. In 1986, Alcan and Gaydon Technology assisted Bertone to reengineer and build five aluminumver- sions of the X1/9. They used the same approach as for the Austin Metro— gauge for gauge substitution in pro- duction tooling, with local doublers in areas identified by finite element anal- ysis. The main difference was that the bolt-ons were also aluminum. Outer skins for the hood, doors, and trunk lid used 6010-T4, while the structure was again made with 5251-O, but this time using coils pretreated in Bresso. One deviation from the ASVT system was the omission of the lubricant, replaced by a strippable PVC lacquer that was compatible with the production condi- tions of the press shop. It was removed prior to adhesive application and as- sembly. While most parts formed rea- sonably well and could be made to fit with additional rework, the more diffi- cult parts required TIG welding repairs, and a few had to be made entirely by hand using prototype methods. Small brackets, hinges, and other small local reinforcements remained in steel, but were phosphate and E-coated before assembly. Again, all adhesive applica- tions were done by hand. The prototypes underwent a full regimen of testing, from static and dy- namic torsional and flexural rigidity, hot climate test, various accelerated durability tests, frontal and rear crash tests at the Fiat Safety Research Center, outside and inside sound transmission tests, and finally, a 12-week corrosion durability test of an unpainted vehi- cle. While not all tests were completely successful, the failures could be readi- ly traced to the compromises made in the prototype design and construction. Most importantly, the durability of the Fig. 2 — 1982 BL Technology ECV3. Fig. 3 — ECV3 body structure.