Page 21 - MetalForming-Apr-2018-issue

The Science of Forming
can recycling efforts, which work pri- marily because all can bodies consist of one of two grades, AA3004 or AA3104. Higher-strength alloys such as AA5182 are needed for lids, as they do not undergo the same forming process as bodies, and, therefore, do not have the opportunity to work-hard- en. Despite the higher magnesium con- tent, AA5182 is considered to be recy- cling-compatible with AA3004/3104. Aluminum lines that melt and roll bev- erage-can stock typically only serve this market, and have optimized chem- istry and processing accordingly. Sig- nificant quantities of scrap from other 5XXX/6XXX applications are not incor- porated into the melt, since it will make the chemistry requirements of 3XXX- series can body material more difficult to achieve.
Scrap segregation takes on increas- ing importance for manufacturers tar- geting automotive applications. Engi- neered scrap can encompass 40 percent of large panels—consider the window cutout of doors. In preparation for the 2015 F-150 launch, Ford installed a $60-million pneumatic scrap-handling system that returned scrap aluminum back to the producer mill, creating a true closed-loop recy- cling process. Scrap value increased by 50 percent after segregating by grade and producer, allowing for a savings of $80 million/year and ROI within less than a year. In addition to exposed applications requiring 6XXX alloys, some companies use these products on unexposed applications as well to facilitate scrap recycling, in spite of the higher material costs as compared with 5XXX.
Automobile manufacturers have yet to specify 7XXX-series alloys for more than a few parts. When they do, sepa- rating different grades will take on even greater importance, as high levels of copper and zinc must be kept out of the recycling stream of other alu- minum-alloy families. MF
Die Design Courtesy of Miro Mfg.
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