The everyday steel sections behind frames, brackets and gates. What each profile is for, popular sizes, weights, and how to order cut to length from Heiton Steel.
What is merchant bar?
Merchant bar refers to the smaller standard mild steel profiles produced for general engineering and fabrication, as opposed to large structural sections. They are easy to cut, drill and weld, which makes them the most widely used steel in workshops and on site.
- Angle (L) – equal or unequal legs; stiff and easy to fix, used for frames and edges.
- Flat – rectangular bar for straps, brackets, base plates and braces.
- Tee (T) – T-shaped section for partitions, frames and supports.
- Round – solid round bar for pins, shafts, balustrades and bracing.
- Square – solid square bar for decorative work, gates, frames and grilles.
Popular sizes and weights
Equal angle
| Size (mm) | Thickness (mm) | Weight (kg/m) |
|---|---|---|
| 25×25 | 3 | 1.11 |
| 40×40 | 4 | 2.42 |
| 50×50 | 5 | 3.77 |
| 50×50 | 6 | 4.47 |
| 75×75 | 8 | 8.99 |
| 100×100 | 10 | 15.0 |
Flat bar
| Width × thickness (mm) | Weight (kg/m) |
|---|---|
| 25 × 5 | 0.98 |
| 40 × 5 | 1.57 |
| 50 × 6 | 2.36 |
| 50 × 10 | 3.93 |
| 75 × 10 | 5.89 |
| 100 × 10 | 7.85 |
Round & square bar
| Size (mm) | Round (kg/m) | Square (kg/m) |
|---|---|---|
| 10 | 0.62 | 0.79 |
| 12 | 0.89 | 1.13 |
| 16 | 1.58 | 2.01 |
| 20 | 2.47 | 3.14 |
| 25 | 3.85 | 4.91 |
Quick formulas (mild steel): round = 0.00617 × d²; square = 0.00785 × side²; flat = width × thickness × 0.00785. Sizes shown are indicative of common demand.
Typical applications
- Gates, railings, balustrades and grilles
- Brackets, straps, cleats and base plates
- Frames, supports and machine guards
- Agricultural, commercial and general repair fabrication
Merchant bar is straightforward to cut and weld in the workshop. For heavier structural sections we also offer computerised sawing at our Naas Rd. depot, plus our own shot blasting and priming.
Order in three steps
- Tell us the profile (angle, flat, tee, round, square), size and lengths.
- Add finishing where needed, such as shot blast and prime.
- We quote competitively and arrange next-working-day delivery with live tracking where available.
Frequently asked questions
What is the difference between flat bar and plate?
Flat bar is a narrow rectangular section sold by width and thickness in set lengths, ideal for straps and brackets. Plate is wide sheet material sold by area and thickness, used for larger surfaces and gussets.
How do I work out the weight of round bar?
For mild steel, multiply 0.00617 by the diameter in mm squared. A 20 mm round bar weighs about 2.47 kg/m.
Do you stock both equal and unequal angle?
We stock a wide range of angle sizes. Tell us the leg dimensions and thickness you need and we will confirm availability.
Can I get merchant bar cut to length?
Yes, tell us your lengths at quotation. Note that our computerised splay-cutting saw service is aimed at heavier structural sections such as beams, columns and channels.