This specification covers the requirements for non-heat treated carbon steel machine screws. Steel for the machine screws shall be made by open-hearth, basic-oxygen, or electric-furnace process and the screws shall be manufactured by cold forming, thread rolling, and stress-relieve annealing. Heat and product analysis shall be performed to determine the chemical composition of the specimen conforming to the requirements for carbon, phosphorus, and sulfur. Specimens shall be subjected to mechanical tests to verify conformance to the mechanical property requirements such as tensile strength, Rockwell hardness, and ductility.