Carbon steel fasteners are often coated with industrial PTFE (short for polytetrafluoroethylene) in applications that require high strength and corrosion resistance and are economically viable. SAE-AISI 1018, 1020, 1040, 1045/CK45 are common carbon steel grades used to produce these fasteners. Industry specifications such as ASTM A36, A193, A194, A307, A354, A449, A540, A563, F1554 and SAE J429 cover high strength carbon steel fastener grades.