ACSR, is a concentric-lay-stranded conductor made from round aluminum 1350-H19 (extra hard) wires and round, coated steel core wire(s).
The steel core, that is the mechanical support, can be composed of galvanized steel wires or Aluminum Clad Steel wires (ACS).
The wires of the conductive layers could be made of hard drawn aluminum or of thermal aluminum alloy and they have a rounded section.