In the field of engineering materials, it refers to a type of angle steel with a right-angle L-shaped cross-section and unequal lengths on both sides, as opposed to equal-sided equilateral angle steel. It is widely used in the structures and engineering structures of various municipal public, residential buildings, and military industries, such as industrial beams, bridges, transmission towers, lifting and transportation machinery, ships, industrial furnaces, reaction towers, container frames, and warehouses, etc. Due to its lower consumption compared to single-side angle steel, it is relatively more expensive.