AS NZS 1214:2016 pdf free

AS NZS 1214:2016 pdf free.Hot-dip galvanized coatings on threaded fasteners (ISO metric coarse thread series) (ISO 10684:2004, MOD)
Parts shall be cleaned. During the cleaning process, hydrogen could be absorbed into the steel. The hydrogen may not effuse completely in the galvanizing bath and consequently, may lead to brittle failure. Unless otherwise agreed, parts heat treated or work hardened to a hardness of≥320 HV shall be cleaned using an inhibited acid, alkaline or mechanical process. Immersion time in the inhibited acid depends on the as-received surface condition and should be of minimum duration.
NOTE An inhibited acid is an acid to which a suitable inhibitor has been added to reduce corrosive attack on the steel and absorption of hydrogen.
Normal temperature galvanizing is carried out at a bath temperature of 455 °C to 480 °C. High temperature galvanizing is used to produce a smoother and thinner coating and is carried out at a bath temperature of 530 °C to 560 °C. The finish obtained using the high temperature process is dull. In order to avoid micro-cracks, bolts, screws and studs of property class 10.9 in sizes M27 and above, shall not be high temperature galvanized.
Dimensional limits for ISO metric screw threads M10 to M64 before and after coating are specified in ISO 965-1 to ISO 965-5. AlI other dimensions and tolerances of fasteners apply before hot dip galvanizing.Dimensional limits for internal and external screw threads M8 with thread tolerances 6AX and 6AZ for internal threads and 6az for external threads are specified in Annex B.
NOTE It is not possible to check the thread tolerance of a hot dip galvanized part by stripping the coating and gauging the thread thereafter, since some steel is dissolved from the part during the galvanizing process.This clause applies only to parts with thread tolerances in accordance with ISO 965-1 to ISO 965-5 and with marking according to the marking requirements for fasteners as given in ISO 898-1 and ISO 898-2. The marking specified in 6.2.2 and 6.2.3 shall be carried out in addition to the marking according to ISO 898-1 and ISO 898-2.
The application of zinc coating by the hot dip process results in the deposition of a heavy coating thickness of zinc (always in excess of 40 um). Hence, it is necessary to manufacture screw threads to special limits in order to accommodate such heavy coatings.AS NZS 1214 pdf free download.