A flat bar is a long, rectangular metal bar with a smooth surface and straight sides. It is often constructed of steel, stainless steel, aluminum, or brass. Due to their ease of machining, bending, and welding, flat bars are flexible and have many applications in building, manufacturing, fabrication, and decoration.

Flat bars are frequently utilized in many sectors due to their versatility and convenience. Typical applications include structural support in construction, which functions as beams, braces, and reinforcements. Flat bars are used in manufacturing to create equipment components, braces, and frames because they are easy to process and shape. They are also widely used in metal fabrication to create gates, fences, railings, and architectural components. Flat bars are used in automobile applications such as chassis components, braces, and body reinforcements. Flat bars are also used in industrial applications for conveyor systems, material handling equipment, and storage racks due to their load-bearing capability and durability.

The primary distinctions between hot-rolled and cold-rolled flat bars are their production procedures and subsequent qualities. Hot-rolled flat bars are created at high temperatures, which makes them pliable and more straightforward to shape. They often have a rougher surface polish and rounded edges. In contrast, cold-rolled flat bars are produced at room temperature, giving them a finer surface finish and sharper edges. They also often feature better dimensional tolerances and higher surface quality. Hot-rolled flat bars are commonly employed in structural applications with less critical dimensions. In contrast, cold-rolled flat bars are preferred in applications that need tighter tolerances and a smoother finish, such as machining or fabrication.