Grainger.com

O1 Tool Steel Rectangular Bar, Material Tool Steel, Material Grade O1, Thickness 0.25 in, Thickness Tolerance +/-0.001 in, Overall Length 18 in, Overall Width 1 in, Fabrication Hot Rolled, Heat Treatable Yes, Heat Treatment Oil Hardened, Mechanical Finish Precision Ground, Yield Strength 55,000 psi, Tensile Strength 95,000 psi, Brinell Hardness 177 to 212, Rockwell Hardness C18, Standards AISI O-1, ASTM A681-08, FEDERAL QQT 570 REV C, SAE J437, UNS T31501, Includes Material Certificate Yes