The tensile strength of mild steel depends on how the steel was formed. AISI 12L14 steel, cold drawn, 3/4 inch to 1 1/2 inches in diameter, has a ultimate tensile strength of 78,300 pounds per square inch.
Ultimate tensile strength is an intensive property, and its value does not depend on the size of the material undergoing strength testing. Variables that do affect UTS are the way the mild steel is treated: whether it has been hot or cold drawn, hot or cold rolled or undergone heat treatments, such as annealing. Surface and internal defects, such as inclusions, reduce the UTS of a material.