Angle iron, also called steel angle, is one of the most useful shapes in steel. It is just two legs at 90 degrees. But the types of angle iron are not all made the same way, and choosing the wrong one costs money or strength. This guide explains the two main types, how to choose holes and finish, and the jobs each one is best at.
Type 1: Hot-rolled structural angle
Structural angle is rolled at a steel mill from a red-hot billet, passed through shaped rolls until it forms an L. The result is a solid section with a rounded inside corner, called the fillet, and slightly rounded toes. In the U.S. it is usually made to ASTM A36 (36,000 psi minimum yield). It is sized in fractional inches, such as 2″ x 2″ x 1/8″ or 3″ x 3″ x 1/4″, and its section properties are published by AISC, so engineers can design with it.
Choose it for: frames that carry load, trailer and truck racks, lintels, equipment bases, structural brackets, and anywhere the drawing says “L” and A36.
SteelFront options: structural angle iron in six sizes, and punched structural angle for 1/2″ bolts.
Type 2: Roll-formed (cold-formed) angle
Roll-formed angle starts as flat steel strip. A line of roller stands bends it, a little at each stand, until it reaches 90 degrees. It is formed at room temperature, so the corner is sharp and the thickness is the same everywhere, often given as a gauge (11 gauge is about 1/8″). The strip can be zinc coated before forming, which is how pre-galvanized angle is made. Holes can be punched in the same pass.
Choose it for: shelving, workbenches, garage door opener hangers, light framing, bolt-together racks and catwalk parts where a punched hole pattern saves time.
SteelFront options: roll formed angle iron, punched angle iron for 1/2″ bolts, and garage door angle iron for 3/8″ bolts.
Structural vs roll-formed at a glance
| Hot-rolled structural | Roll-formed | |
|---|---|---|
| How it is made | Rolled hot at the mill | Bent cold from flat strip |
| Inside corner | Rounded fillet, thicker at the heel | Sharp bend, even thickness |
| Thickness callout | Fractions (1/8″, 1/4″) | Gauge or fraction (11 ga, 1/8″) |
| Grade | ASTM A36 typical | Varies with strip grade |
| Published design properties | Yes (AISC) | No standard table |
| Galvanizing | Hot-dip after fabrication | Pre-galvanized coil, or hot-dip |
| Best for | Load-bearing and structural work | Light framing, shelving, bolt-together builds |
Punched or unpunched?
Unpunched angle is for welding or for a custom hole layout. Punched angle has holes in one leg (single punch) or both legs (double punch), so it can be bolted with no drill. SteelFront’s standard punched angle has .563″ holes on 2″ centers for 1/2″ bolts, the same pattern on structural and roll-formed versions. Our garage door angle has 3/8″ bolt holes 1″ apart.
Raw or galvanized?
Raw steel is the best choice for welding and painting. Galvanized angle is for outdoor, wet and corrosive sites. See galvanized angle iron for pre-galvanized vs hot-dip.
What angle iron is used for
Furniture, shelving and workbenches
Four uprights of punched angle plus horizontal angle rails and wood planks make heavy-duty, free-standing shelving with nothing but nuts and bolts. Angle legs make strong workbench and table frames. A stanchion lug makes a solid foot.
Garage door openers
Look up in almost any garage and the opener hangs from punched angle. Its close hole spacing lets installers set the opener at any height. See garage door angle iron.
Walkways, catwalks and stairways
Angle frames and braces the walkways and stairs that give access to storage tanks, silos and equipment. Punched angle bolts to our stair treads, walkway pans and toe boards. See industrial catwalk parts and tank battery parts.
Construction and fabrication
Lintels over openings, ledgers, embeds, bracing and frames for equipment and signs. Our tank cleanout frame is itself made from 2″ x 3″ x 1/4″ structural angle. See parts for contractors.
Farm and ranch
Gates, feeders, trailer racks, tank stands and countless repairs. See agriculture parts.
Sizes and weights
Need weight per foot, thickness options or the weight of a 20′ bar? Use the angle iron size chart. Ready to buy? Compare every product on the angle iron page.
Frequently asked questions
What are the two types of angle iron?
Hot-rolled structural angle and roll-formed (cold-formed) angle. Structural angle is rolled at the mill from hot steel and has a rounded inside corner. Roll-formed angle is bent from flat strip at room temperature and has a sharper corner and an even, gauge-based thickness.
Is angle iron actually iron?
No. Modern angle iron is steel. The name comes from the 1800s, when the shape was rolled from wrought iron. “Angle iron”, “steel angle” and “angle bar” all mean the same product today.
What is angle iron used for?
Frames, brackets, bracing, shelving, lintels, ledgers, trailer and truck racks, equipment stands, garage door opener supports, catwalk and stair framing, tank cleanout frames and countless repairs. It is popular because the L shape is stiff in two directions and easy to bolt or weld.
Is roll-formed angle weaker than structural angle?
For the same leg size, usually yes. Roll-formed angle is often thinner and has a sharp inside corner, while structural angle is thicker at the corner and made to the published A36 strength values. Roll-formed angle is still plenty for shelving, light frames and bolt-together builds.
What is A36 angle?
Angle made from ASTM A36 carbon steel, which has a minimum yield strength of 36,000 psi and a tensile strength of 58,000-80,000 psi. It is the most common structural angle in the United States. See what is A36 steel.
What is the difference between equal and unequal angle?
Equal-leg angle has two legs the same length (2″ x 2″). Unequal-leg angle has one longer leg (3″ x 2″), which is stiffer in one direction. It suits ledgers, shelf supports and lintels where the load comes from one side.