Common Structural Steel Shapes
Structural steel comes in standardized shapes that are designed for efficient load-carrying. Here are the dimensions and properties for the shapes you’ll encounter most in machine design, fabrication, and construction.
Steel Angle (L-shapes)
| Size (legs × thickness) | Weight (lb/ft) | Area (in²) | Ix (in⁴) | Iy (in⁴) |
|---|---|---|---|---|
| L1×1×1/8 | 0.80 | 0.234 | 0.022 | 0.022 |
| L1-1/2×1-1/2×1/8 | 1.23 | 0.360 | 0.074 | 0.074 |
| L1-1/2×1-1/2×1/4 | 2.34 | 0.688 | 0.131 | 0.131 |
| L2×2×1/4 | 3.19 | 0.938 | 0.348 | 0.348 |
| L2×2×3/8 | 4.70 | 1.36 | 0.479 | 0.479 |
| L2-1/2×2-1/2×1/4 | 4.10 | 1.19 | 0.703 | 0.703 |
| L3×3×1/4 | 4.90 | 1.44 | 1.24 | 1.24 |
| L3×3×3/8 | 7.20 | 2.11 | 1.76 | 1.76 |
| L4×4×1/4 | 6.60 | 1.94 | 3.04 | 3.04 |
| L4×4×3/8 | 9.80 | 2.86 | 4.36 | 4.36 |
| L4×4×1/2 | 12.80 | 3.75 | 5.56 | 5.56 |
Steel Channel (C-shapes)
| Designation | Depth (in) | Width (in) | Weight (lb/ft) | Ix (in⁴) | Sx (in³) |
|---|---|---|---|---|---|
| C3×4.1 | 3.00 | 1.410 | 4.1 | 1.66 | 1.10 |
| C3×6 | 3.00 | 1.596 | 6.0 | 2.07 | 1.38 |
| C4×5.4 | 4.00 | 1.584 | 5.4 | 3.85 | 1.93 |
| C4×7.25 | 4.00 | 1.721 | 7.25 | 4.59 | 2.29 |
| C5×6.7 | 5.00 | 1.750 | 6.7 | 7.49 | 3.00 |
| C6×8.2 | 6.00 | 1.920 | 8.2 | 13.1 | 4.38 |
| C6×13 | 6.00 | 2.157 | 13.0 | 17.4 | 5.80 |
| C8×11.5 | 8.00 | 2.260 | 11.5 | 32.6 | 8.14 |
| C10×15.3 | 10.00 | 2.600 | 15.3 | 67.4 | 13.5 |
Steel Square Tube (HSS)
| Size (in) | Wall (in) | Weight (lb/ft) | Area (in²) | I (in⁴) |
|---|---|---|---|---|
| 1×1 | 1/8 | 1.57 | 0.430 | 0.133 |
| 1-1/2×1-1/2 | 1/8 | 2.47 | 0.680 | 0.478 |
| 2×2 | 1/8 | 3.37 | 0.930 | 1.18 |
| 2×2 | 3/16 | 4.86 | 1.34 | 1.60 |
| 2×2 | 1/4 | 6.26 | 1.69 | 1.94 |
| 3×3 | 3/16 | 7.58 | 2.09 | 5.72 |
| 3×3 | 1/4 | 9.86 | 2.69 | 7.10 |
| 4×4 | 1/4 | 13.44 | 3.59 | 17.7 |
| 4×4 | 3/8 | 19.08 | 5.09 | 23.4 |
Which Shape for Which Application?
| Shape | Best For | Avoid When |
|---|---|---|
| Angle (L) | Bracing, gussets, brackets, framing connections | High bending loads (low I about weak axis) |
| Channel (C) | Framing, machine bases, brackets, rails | Loading not in plane of web (causes twisting) |
| Square/Rect Tube (HSS) | Columns, trusses, frames, guard rails | Connections are harder to make than open shapes |
| I-Beam (W/S) | Beams (bending in strong axis), crane rails | Torsion (I-beams are weak in twist) |
| Round Tube | Columns, roll cages, torsion members | Attaching flat things (hard to weld/bolt to round surface) |
Related: Beam Deflection Formulas | Welding Symbols Guide | Steel Numbering System