The standard steel core used for ACSR is galvanized steel, but zinc-5% aluminium mischmetal alloy coated steel (sometimes called by the trade-names Bezinal or Galfan) and aluminium clad steel (sometimes called by the trade-name Alumoweld) are also available. Higher strength steel may also be used.
In the United States the most commonly used steel is designated GA2 for galvanized steel (G) with class A zinc coating thickness (A) and regular strength (2). Class C zinc coatings are thicker than class A and provide increased corrosion protection at the expense of reduced tensile strength. A regular strength galvanized steel core with Class C coating thickness would be designated GC2. Higher strength grades of steel are designated high-strength (3), extra-high-strength (4), and ultra-high-strength (5). An ultra-high-strength galvanized steel core with class A coating thickness would be designated GA5. The use of higher strength steel cores increases the tensile strength of the conductor allowing for higher tensions which results in lower sag.