Steel Angles: Equal and Unequal Angle Sizes and Uses
Steel angle sections explained: equal and unequal angles, designation, common sizes, weight formula, grades and uses for bracing, cleats, lintels, towers and frames.
Saudi Steel Work Editorial Team · · 3 min read
Short answer: Steel angles are L-shaped sections with equal or unequal legs, designated by leg lengths and thickness, e.g. L 75×75×8. They are used for bracing, connection cleats, lintels, lattice towers, frames and supports. Weight per metre is approximately (A + B − t) × t × 0.00785 kg with dimensions in mm.
Angles are among the simplest and most useful steel sections. They appear in almost every structure as bracing, cleats or secondary framing.
Equal vs unequal
- Equal angles have two legs of the same length, e.g. L 100×100×10.
- Unequal angles have different leg lengths, e.g. L 150×90×10.
Dimensions follow EN 10056-1 for European angles, BS EN 10056 for British practice, or ASTM A6 for American angles (often in inches).
Common uses
- Bracing in buildings, towers and trusses
- Cleats connecting beams to columns
- Lintels over openings in masonry
- Lattice towers for transmission and telecoms
- Frames for tanks, equipment and supports
- Edge trims around floor openings and decking
Weight formula
For a quick estimate (ignoring the root radius):
kg/m ≈ (A + B − t) × t × 0.00785
| Angle | Approximate kg/m |
|---|---|
| 50×50×5 | 3.7 |
| 75×75×8 | 8.9 |
| 100×100×10 | 15.0 |
Published section tables are slightly higher because of the root fillet. Use our steel weight calculator for estimates and mill tables for final figures.
Design considerations
Angles connected through one leg experience eccentric loading, which reduces their effective capacity in tension and compression. Engineers account for this — another reason not to substitute sizes without checks.
Grades and finishes
Typically S275JR, S355JR or ASTM A36, supplied black, primed or hot-dip galvanized (hot-dip galvanizing explained).
Buying tips
- Specify both legs and thickness
- Confirm stock length (6 m or 12 m)
- Request galvanizing after fabrication for outdoor frames
Angles are available on enquiry within our structural steel sections range.