Effect of Twin-Roll Casting Parameters on Mechanical and MicrostructuralProperties of AA5083-H321 Sheet

The purpose of the present paper is to study the mechanical and microstructural properties of the twin-roll cast and cold rolled AA5083 aluminum alloy sheet in strain-hardened H321 temper. To reach this goal, first, a sound surface slab of 8.90mm thick and 1260mm wide was cast by a 15° tilt back twin roll caster at a casting speed of 490mm/min. After homogenization at 520°C, the product was cold rolled to two thicknesses of 6.30mm and 3.85mm with an intermediate annealing at 370°C and final stabilization at 180°C. Optical and scanning electron microscopy (SEM) investigations of the as-cast state depicted the segregation of intermetallic particles mainly in grain boundaries, which were the cause of grain removal observed in the fracture surface of tensile test samples. In addition, mechanical properties indicated an increase in total elongation after homogenization heat treatment due to the elimination of the grain boundary segregations. Finally, it was observed that the properties of the 3.85mm thick sheet were consistent with the H321 temper requirements according to ASTM B 290M standard due to applying sufficient cold reduction

Keywords:

AA5083 aluminum alloy , Twin roll casting , Cold rolling , H321 strain-hardened temper