4130 Alloy Steel Round Tube Material Alloy Steel Material Grade 4130 Fabrication Seamless Heat Treatable Yes Heat Treatment Annealed Mechanical Finish Mill Inside Diameter 2.5 in Outside Diameter 3 in Overall Length 12 in Wall Thickness 0.25 in Yield Strength 66 700 psi Machinability Not Rated Rockwell Hardness B82 Appearance Metallic Application Aircraft Exterior Fasteners Gears Structural Frames Brinell Hardness 156 Includes Material Certificate Yes