Recycle-Friendly Aluminum Alloy Sheets for Automotive Applications Based on Hemming

Unavoidably, Fe impurities are mixed into Al alloys during recycling of aluminum automotive parts. High Fe content recycle-friendly aluminum alloy sheets (RASs) are discussed in terms of their applications to car body parts and closures. RASs have advantages, such as they are low cost and light weight, they require less energy to process, and they reduce emissions when used in vehicles. The hemming ability of RASs was investigated through various quenching rates and hot-rolling reduction rates. The hemming factor (HF) values of low Fe content samples (0.1 and 0.3 wt% Fe content) were 2 and 3. The hemming ability of samples with an Fe content of 0.5 wt% was unacceptable for applications to automotive outer closures (i.e., HF values of 4 and 5). The HF values changed from 3 to 5 for even higher Fe content samples (0.8 wt% Fe), depending on the quenching and hot-rolling reduction rates. Lower quenching (air quenching) and lower hot-rolling reduction rates (6-pass hot rolling) both improved the hemming ability of the high Fe content samples. A low-cost and recycle-friendly aluminum alloy automotive sheet from end-of-life vehicles is presented, and its hemming properties are characterized.