LoCoLite first successful forming trials
On the 7th and 8th May 2014, the HFQ process was put to the test as part of the LoCoLite project, by forming a component using an existing press tool designed by CRF. The component was chosen by the LoCoLite consortium as it reflected a part that could not be made with high strength aluminium alloys using conventional cold forming techniques. The collaborative effort involving the partners ICL, ITL, CRF, AP&T, PAB, DIAD, ESI and STR combined the expertise of blank design, process simulation, manufacture, automotive tooling and sheet forming. The two-day trial period demonstrated the successful forming of a rear-floor component from both AA6082 and AA7075, with over 30 pieces being formed.
The work was preceded by computer simulations (Figure 1) conducted to optimise the process parameters and initial blank shape for achieving a successful component. The component produced using HFQ was completely successful with no detectable fractures/localised necking, thermal distortion or spring-back as predicted by the simulation work. The differences between the component formed by HFQ (Figure 2a) and under the cold (Figure 2b) processes are clearly seen. It was found that traditional cold forming of both AA6082 and AA7075 high strength aluminium alloys failed to produce the required shape, with many fractures being found in various locations of the blank.
Components produced from both AA6082 and AA7075 are shown in Figure 3. As can be seen, the HFQ process shows that both of these difficult to press-form alloys, can be used for making volume production parts.
Furthermore, hardness measurements after the artificial ageing process of the material revealed the potential for HFQ to achieve a high post form strength. This enables the use of thinner and hence lighter sheet material, helping automotive producers achieve their efficiency and hence CO2 emission targets. The wide range of bend radii, draw depths and varying geometries formed from a single sheet of either AA6082 or AA7075 alloy in these trials prove HFQ to be a promising technology for all industries interested in forming high strength, complex, lightweight components from sheet metal alloys.
Figure 1: PAMSTAMP simulation of blank thickness distribution.
Figure 2: Forming of complex shaped component under (a) HFQ and (b) cold forming conditions.
Figure 3: Formed components from both: (a) AA6082 and (b) AA7075.