AS NZS 1214:2016 Hot-dip galvanized coatings on threaded fasteners (ISO metric coarse thread series) (ISO 10684:2004, MOD)
6.3 Special requirements for marking when supplying fasteners in sealed containers
If hot dip galvanized bolts or screws and mating nuts are packed together and supplied in the manufacturer’s sealed container, the additional marking of the bolts, screws or nuts as described in 6.2.2 and 6.2.3 is not mandatory. The label on each sealed container shall indicate the additional marking as required in 6.2.2 and 6.2.3.
Additional marking of products or labelling of containers as described in 6.2.2 and 6.2.3 is not mandatory for fasteners with a special marking related to a product standard which specifies the thread tolerance for hot dip galvanized bolts, screws, studs or nuts and, therefore, does not allow the manufacturer to choose the thread tolerance.
7 Mechanical properties of nuts tapped oversize and undersize threaded bolts,screws and studs
For bolts, screws, studs and nuts W M12, the requirements of ISO 898-1 and ISO 898-2 shall be met after hotdip galvanizing. For the sizes M8 and M10, proof loads and stresses under proof loads for nuts and ultimate tensile loads and proof loads for bolts, screws and studs are specified in Annex A.
8 Coating requirements
8.1 Appearance of zinc coating
The hot dip galvanized parts shall be free from uncoated areas, blisters, flux deposits, black spots, dross inclusions and other defects that would impair the intended use of the parts. Dull appearance shall not constitute grounds for rejecting parts.
8.2 Considerations for hot dip galvanized washers
Hot dip galvanized washers tend to bond to each other and suitable acceptance criteria should be agreed
upon at the time of ordering.
8.3 Zinc coating thickness
The local coating thickness shall be a minimum of 40 µm and the batch average coating thickness shall be a minimum of 50 µm. The measurement of the local coating thickness shall be made on measuring areas as shown in Figure 3.
Measurement of the local coating thickness shall be conducted by the magnetic method in accordance with ISO 2178 on every production lot. To calculate the local coating thickness, a minimum of five readings shall be taken and averaged. In case the geometry does not permit five readings, five samples shall be used to establish the readings to be averaged. In case of dispute, the gravimetric method in accordance with ISO 1460 shall be used. For the calculation of the batch average coating thickness, the surface area of the fastener can be evaluated according to Annex D.