Assessment of ZK60A magnesium billets for forging depending on casting methods by upsetting and tomography

The workability of ZK60A billets fabricated by semi-continuous casting, subsequent extrusion, and die casting were evaluated. To determine the deformation capability of the three different billets, upsetting tests were conducted at elevated temperatures and two different strain rates. The differences in critical height reduction depending on the casting methods were investigated based on inherent defects inside the billets, and variation in the mechanical property with the location within the semi-continuously casted billet was investigated by X-ray tomography and electron backscatter diffraction. Uniformity of density substantially affected the mechanical properties of the billet. The drastic decrease in the workability of the die-casted billet at temperatures higher than 320°C was also discussed.