Alloy Steel Round Tube, Material Alloy Steel, Material Grade 4130, Fabrication Seamless, Heat Treatable Heat Treatable, Heat Treatment Air-Hardened, Mechanical Finish Mill, Inside Diameter 0.509 in, Outside Diameter 5/8 in, Overall Length 36 in, Wall Thickness 0.058 in, Yield Strength 63,000 psi, Machinability Not Rated, Rockwell Hardness 92 HRB, Appearance Metallic, Application Aircraft Exterior, Fasteners, Gears, Structural Frames, Brinell Hardness 197 BHN