A36 hot rolled steel flat bars, or flat stock, are an excellent candidate for most processing techniques. A36 hot rolled steel flat bars have a rough, blue-grey finish, dull rounded edges and have inexact dimensions throughout length. A36 material is a low carbon steel, often referred to as mild steel which is long lasting and durable. Common applications include shelving, sculptures, trim, bracing, and brackets. ASTM A36 / A36M-08 is the standard specification for carbon structural steel.