Galvalume® roll jacketing is manufactured from low carbon cold rolled steel that has a continuous hot dipped aluminum-zinc alloy coating applied to the outer surfaces for resistance to corrosion. The special coating is composed of 55% aluminum, 1.6% silicon, and 43.4% zinc. The finished sheet has yield strength of 38,000-53,000 psi, a tensile strength of 50,000-65,000 psi, 20-36% elongation, and a hardness of 50-65 HRB.