4142 Alloy Steel Rectangular Bar, Material Alloy Steel, Material Grade 4142, Thickness 0.3125 in, Thickness Tolerance +/-0.001 in, Overall Length 18 in, Overall Width 3 1/2 in, Fabrication Hot Rolled, Heat Treatable Yes, Heat Treatment Pre-Hardened, Mechanical Finish Mill, Yield Strength Not Rated, Tensile Strength Not Rated, Brinell Hardness 187, Rockwell Hardness B94, Machinability 50 Percent, Standards ASTM A322, Appearance Metallic, Includes Material Certificate Yes, Shape Rectangular Bar