What’s the difference between Pipe and Tube?
Black Pipe vs Round Tube
| Feature | Black Pipe | Round Tube |
|---|---|---|
| Primary Use | Fluid, gas, pressure systems | Structural and fabrication |
| Sizing Method | Nominal Pipe Size (NPS) | Actual Outside Diameter (OD) |
| Wall Thickness | Defined by schedule (SCH 40, 80) | Defined by gauge or wall (e.g. .065, .120) |
| Inside Diameter | Critical (flow capacity) | Not typically a primary factor |
| Outside Diameter | Fixed per nominal size | Exact and consistent |
| Tolerances | Looser | Tighter (especially A513) |
| Surface Finish | Rough, mill scale | Smoother (especially ornamental) |
| Threading | Can be threaded | Not designed for threading |
| Best For | Plumbing, gas lines, mechanical systems | Frames, rails, fabrication, structures |
Not sure which to choose?
Use Black Pipe for anything involving flow, pressure, or threading.
Use Round Tube for fabrication, structural work, and clean finished builds.