A novel flexible ssm and hpdc equipment to process secondary aluminium alloys for decarbonising lightweight parts in automotive sector

LCA approach guidelines for automotive sector recently introduced [1, 2] highlighted how much important is working on decarbonisation of Al casting processes to produce vehicle components. Broadening use of secondary aluminum alloys, instead of high energy intensive primary aluminum alloys, is key for environment preservation. Unfortunately, primary aluminum alloys are preferred by automotive OEMs because impurities (mainly Fe) present in secondary aluminum alloys can cause mechanical performance decrease. Semisolid-state process route is still thought to drastically reduce some physiologic casting defects, thus positively balancing decrease by impurities. Basing on these premises, a pre-industrial prototype 4-columns 700 kN clamping force vertical casting machine has been designed and constructed to cast secondary aluminum in two modes: medium-pressure die casting and semisolid state. Investigation on A356 secondary alloys samples obtained by both process routes have been investigated in order to compare microstructure integrity and key-features impacting on final mechanical properties.