Commonly known as angle iron angle, perpendicular to each other on both sides of a triangle strip steel. There are equilateral angle and unequal angle of the points. Equilateral angle of the two sides equal width. Its specifications indicated by the side edge width × width × edge thickness of a few millimeters. Such as "∠30 × 30 × 3", it means that edge width of 30 mm, edge thickness of 3 mm equilateral angle. Models can also be said that the model is a few centimeters wide edge, as ∠3 #. Models do not represent different sides of the same thickness dimension models, contracts and other documents will thus angle of edge width, edge thickness dimension completely filled to avoid alone model representation. Hot-rolled edge angle specifications for the 2 # -20 #. Angle may require different structures composed of a variety of different force components, but also for connections between components. Widely used in various building structures and engineering structures, such as beams, bridges, transmission towers, material handling equipment, marine, industrial furnace, reaction tower, container frame and warehouses.