Angle iron is a popular type of structural steel. Two steel strips meet at a 90-degree angle to form a “L” profile. This gives you the most strength for the least amount of weight. Angle iron, as a structural material, is most commonly used for frameworks and right-angle joints. Angle iron is also useful for making home-made tools, temporary and permanent jigs for metal work and construction, and as a straight edge when marking and cutting different materials.