Angle iron is a general term used to describe a long, rectangular piece of sheet metal or flat bar folded at a 90 degree angle along its long axis, forming an L shape. Many variations on this basic type exist. Most often used in construction as a structural, reinforcement, or support element, these pieces can be decorative as well as functional, and many different metals are used to make them. The term "angle iron" is used to refer to the shape of the piece rather than the material from which it is made and is a holdover from earlier times when they were made almost exclusively from iron. Today, steel and aluminum angle iron is the most common, although other metals, such as brass, are sometimes used.
Variation in types of angle iron can occur in a number of areas. Shape and material are the two main variations. Holes, perforations or cut outs, and finishes and coatings are others. All of these possibilities create a very large number of possible styles.
While steel is the most common metal for angle iron, many other metals can be used. Aluminum angle irons are very common, and are popular for many uses due to their strength to weight ratio and resistance to corrosion. Titanium, bronze, copper, and brass are just a few other metals that are sometimes used. Stainless steel is another popular material.
The number of shape variations for angle iron is almost limitless, and some manufacturers will custom make a specific shape according to a customer's needs. Beveled edges, curves, legs of unequal length, hemmed edges and other shapes are common. The angle, which is set at 90 degrees in a standard angle iron can also be varied. Complex shapes with multiple angles and asymmetric designs are also possible. Holes, cut outs, and perforations may also be punched in the surface of a piece for use with hardware such as screws, bolts, or hooks or to accommodate the shapes of other work pieces.
A great number of finishes are possible for all types of angle iron. Finishes can be one of two types, those that prepare the material itself and those that are applied. The first type of finish consists of techniques like polishing and buffing. The second includes coatings of all types, such as powder coating, galvanizing, electroplating, and durable vinyl coatings.