In today’s Automotive world, there is NO need to advocate “Light weighting”. Government policies for carbon footprint reduction combined with high safety standards are driving OEMs to adopt advanced manufacturing technologies.
Steel hot forming is selected as most preferred way to reduce weight as it is easy to adopt and commercially known. It had many advantages compare to conventional cold stamping of standard and high tensile steel. The process consists of heating blank to nearly 1000 °C and quenching it in tool to for martensitic structure. Higher strength up to 2000 MPa can be achieved by this process. There are many examples where part weight is reduced by 15 to 20 % by this method.
But Steel hot forming has limitation as specific density of steel is still high. Thus, there is limitation to its weight reduction capability. For further reduction, OEMs have started exploring Aluminium hot forming. This process, similar to steel hot forming improves hardness of the part by series of heating and cooling cycles.
Aluminium has been used in car for a while but mainly into cold forming and specifically to A and B class panels. Some efforts are made to produce Aluminium die cast parts for chassis. The main advantage was to have jointless parts, but the big disadvantage was “wall thickness” limitation of die casting process. Also, commercial viability is also a big question for large die casting parts.
Now hot form aluminium is used for Body-in-White which are strength driven applications. Aluminium hot forming is slowly making its way in mass production with many developments in process optimization. But in India, it has many challenges. “Raw material availability”, “New Technology”, “Tooling Know how” are some of the challenges in adopting this technology in larger scale.
A case study will explain the advantages of Aluminium Hot forming, specifically the HFQ® process.