Understanding the 30 x 30 x 5 mm Equal Angle Designation
A 30 x 30 x 5 equal angle is a hot rolled L section with two legs of 30 mm and a wall thickness of 5 mm. In the EN 10056-1 system the same section is designated L 30 x 30 x 5 and is dimensioned by leg width, leg thickness and a fixed root radius, which allows section properties and theoretical mass to be calculated in the same way by every supplier. The equal leg layout gives the section the same bending behaviour about both principal axes, so it is used mainly as a lightly loaded tie, brace, strut, cleat or trim member rather than as a primary bending element.
Neglecting the root and toe radii, the cross sectional area of the section is about 275 mm2. At a steel density of 7.85 g per cm3 this gives a theoretical mass of approximately 2.2 kg per metre, which remains the practical basis for ordering, pricing and transport planning. Catalogue section properties differ slightly between sources because they include the root radius of the standard profile.
Steel Grades and Mechanical Properties
The same section can be rolled in several structural grades, and the grade rather than the profile sets the permissible stress. Typical grades available in this section and their specified minimum properties are:
| Grade | Standard | Minimum yield strength (MPa) | Tensile strength (MPa) |
|---|---|---|---|
| S235JR | EN 10025-2 | 235 | 360 to 510 |
| S275JR | EN 10025-2 | 275 | 410 to 560 |
| S355JR | EN 10025-2 | 355 | 470 to 630 |
| Q235B | GB/T 700 | 235 | 370 to 500 |
| A36 | ASTM A36 | 250 | 400 to 550 |
| A572 Grade 50 | ASTM A572 | 345 | 450 min |
The values above apply to the thinner sizes; yield strength falls as thickness increases in all of these standards. Mild steel angles are supplied in the as rolled condition with a mill finish. Where corrosion resistance is the governing requirement, the same profile is also produced in weathering steel and in stainless grades.
Delivery Lengths, Tolerances and Processing
Standard mill lengths are 6 m, 9 m, 10 m and 12 m, and cut to length service is normal for fabricators who work to a nesting plan. Dimensional and mass tolerances follow EN 10056-2 for hot rolled angles. The section is easy to process: it can be sheared, sawn, punched, drilled, notched and bent cold, and it can be joined by bolting or welding without special procedures because the carbon content of mild steel is kept low.
Surface protection is usually selected on the basis of the environment. Hot dip galvanising to EN ISO 1461 gives long term atmospheric protection; pre galvanised strip is used for lighter duty; paint and powder coating systems are applied where colour or chemical resistance matters. Angles are normally supplied tied in bundles with steel strip and wrapped in waterproof paper for sea transport.
Typical Applications
Because of its small size and low mass, the 30 x 30 x 5 angle is found in a very wide range of fabricated products:
| Sector | Typical use |
|---|---|
| General fabrication | brackets, cleats, gusset support, machine guards and frames |
| Building and structures | purlin bracing, roof and wall framing, mezzanine stiffeners, stair treads |
| Vehicle and trailer | chassis outriggers, body framing, mounting rails |
| Shipbuilding and marine | stanchions, minor hull framing, deck fittings |
| Infrastructure | fencing posts, sign frames, support and cable tray brackets |
Frequently Asked Questions
Q: What is the weight of a 30 x 30 x 5 mm equal angle?
A: The theoretical mass is approximately 2.2 kg per metre, calculated from a cross sectional area of about 275 mm2 at a steel density of 7.85 g per cm3.
Q: Which standard specifies the dimensions of a 30 x 30 x 5 angle?
A: EN 10056-1 gives the nominal dimensions and mass, and EN 10056-2 gives the tolerances for hot rolled equal and unequal angles.
Q: What grades are available in this section size?
A: Typical grades are S235JR, S275JR and S355JR to EN 10025-2, Q235B to GB/T 700, A36 to ASTM A36 and A572 Grade 50 to ASTM A572, depending on the mill and the required mechanical properties.
Q: Can the angle be supplied galvanised or cut to length?
A: Yes. Hot dip galvanising to EN ISO 1461, pre galvanising, painting, punching, bending and cut to length are all standard processing options.
Q: What lengths are normally available?
A: Mills supply 6 m, 9 m, 10 m and 12 m lengths as standard, and cut to length is offered for fabrication work.
Q: Is a 30 x 30 x 5 angle suitable for structural loading?
A: It is normally used as a secondary or light load bearing member such as bracing, framing or brackets. Where the section carries a calculated structural load, the design check must use the yield strength of the selected grade at the actual thickness.