Melt Conditioned Direct Chill (MC-DC) Casting and Extrusion of AA5754 Aluminium Alloy Formulated from Recycled Taint Tabor Scrap

Abstract

The melt conditioned direct chill (MC-DC) casting process has been used to produce billets and extruded planks of AA5754 alloy formulated from 100% recycled Taint Tabor scrap aluminum. The billets were homogenized and then extruded into flat planks. Optical metallography of the MC-DC cast billets showed equiaxed refined grains in comparison to conventional direct chill (DC) cast and direct chill grain refined (DC-GR) cast billets formulated from the same Taint Tabor scrap. Microstructural evaluation of the extruded planks showed extensive peripheral coarse grain (PCG) for the DC, DC-GR and MC-DC cast planks. The 2 mm and 1 mm MC-DC cast planks produced after cold rolling and heat treatment showed a fully recrystallized microstructure at 380 °C and 300 °C for 10 min respectively with an improvement in mechanical properties over DC-GR cast and similarly processed planks. The as-extruded MC-DC cast planks tensile tested in the transverse direction showed 34% elongation and 213 MPa ultimate tensile strength. These tensile results showed 5.8% higher elongation and 1.2% higher ultimate tensile strength compared with the DC-GR planks after applying high shear melt conditioning.

Direct Chill Casting and Extrusion of AA6111 Aluminum Alloy Formulated from Taint Tabor Scrap

“… Schematic diagram of the melt conditioned direct chill casting (MC-DC) with the rotor-stator shearing device submerged in the sump of a conventional DC casting mold [ 1 ]. …”

“…The challenge for aluminum production is to cut 50% of CO 2 emission by 2050. Re-melting of end-of-life aluminum scrap consumes 5% of the energy required to produce primary aluminum and can saves up to 95% of CO 2 emission [ 1 , 2 ]. In the UK, the main motivation for recycling is the provision of aluminum automotive body-sheet and structural castings from a sustainable end-of-life scrap source for the mass manufacture of lightweight low embedded carbon vehicle bodies.…”

“…The TT supplied for this work by Axion Group UK was from the standard feedstock of old rolled aluminum that is mainly construction scrap. Prior to ingot casting at Norton aluminum, the TT was shredded and processed by hand sorting, magnetic and eddy current separation by Axion [ 1 ].…”

Numerical investigation of pull in control of rectangular AA1050 rolling ingot through the design of convex mould during direct chill casting process

“…Hatic et al [9] numerically studied the impact of changing the inlet geometry on macro-segregation, the flow of melt, the temperature of billet and solid fraction for the production of Al-Cu alloy billet with 240 mm diameter using a direct chill casting technique. Al-Helal et al [10] reported an enhancement in the mechanical properties of planks produced by melt conditioned type direct chill casting process in comparison to direct chill casting. The study reported 1.2% improvement in ultimate tensile strength and an increase in elongation by 5.8%.…”