Low Carbon Steel Hot Dip Galvanized ASTM A563 Grade A Finished Full Pattern Hex Nuts for general purpose fastening applications. Hot Dip Galvanized (HDG) fasteners are ideal for Marine and Exterior applications that require a high degree of corrosion resistance. Hex nuts with a Hot Dip Galvanized finish are intended for use with Bolts, Studs and Threaded Rods that have also been Hot Dip Galvanized. To be hot galvanized fasteners are dipped in a molten zinc bath at a temperature of approximately 850° F and then spun at a high speed to remove the excess zinc. They are then cooled in water to solidify the zinc coating. Due to the additional thickness of the Hot Galvanized Zinc coating on a fastener's threads the nuts are first galvanized and the manufacturer as a secondary process after galvanizing will thread the nuts using a special oversized tap to the specifications of ASTM A153/A153M. This oversize tapping operation on the nut allows for sufficient thread clearance inside the nut threads for them to properly thread onto a bolt or stud that has also been galvanized. Often referred to as "Grade 2" hex nuts, they are used with galvanized Grade 2 or A307 Gr.A steel Carriage and Hex bolts, Low carbon steel threaded rods and other applications that do not require a heat treated fastener. It is not recommended that Hot Dip Galvanized Hex Nuts be used with fasteners that are not also galvanized as the specially clearanced nut threads will fit very loosely on a non-galvanized fastener and may not be secure. Hot Dip Galvanized nuts are also available in Heavy Full or Finished Jam patterns. Heat treated HDG heavy hex nuts meeting the ASTM A563 DH Structural specification are also available.