CSA G164-18:2020 pdf download.Hot dip galvanizing of irregularly shaped articles
4.1 Zinc for coating
The zinc used for the coating shall conform to ASTM B6 or its equivalent and shall be at least equal to the grade designated as“Prime Western" . If a zinc alloy is used as the primary feed to the galvanizing bath, then the zinc used to make that alloy shall conform to ASTM B6 or its equivalent.
4.2 Bath composition
The molten metal in the galvanizing bath shall contain not less than 98.0% zinc by mass. The galvanizer may add relatively small amounts of certain elements (e.g, aluminum, nickel, and tin) to the zinc bath to help in the processing of certain reactive steels or to enhance the surface appearance of the galvanized product. The use of such elements is permitted provided that the bulk chemistry of the galvanizing bath is at least 98.0% zinc by mass. The elements can be added to the galvanizing bath pre-alloyed with the zinc feed, or they can be added to the bath by the galvanizer as a master alloy.
4.3 Ungalvanized areas
An area on an individual piece that remains uncoated after galvanizing that is 25 mm or less at any location along its narrowest dimension but not exceeding 0.5% of the surface area to be coated shall be repaired by the galvanizer in accordance with ASTM A780. The method used to renovate the affected area and the extent of renovation shall be agreed to by the galvanizer and the purchaser. Renovation shall be done according to procedures described in ASTM A780.
Any area larger than this may be renovated if mutually agreeable to galvanizer and purchaser. The method used to renovate the affected area and the extent of renovation shall be agreed to by the galvanizer and the purchaser. Renovation shall be done according to procedures described in ASTM A780.
5.1 The coating thickness requirements for the various classes of material shall be as given in Table 1.Coating thickness may be determined by non-destructive tests, magnetically, electronically, or by weigh-galvanize-weigh methods. Coating thickness may be also determined by weigh-strip-weigh or metallographic examination but these are destructive tests.
5.2 For coating thickness measuring methods described by Clauses 7.3.2 and 7.3.4, no individual coating thickness reading shall be less than 90% of the required minimum thickness of coating for the class of material being tested (see Table 1). The average of the five readings shall not be less than the minimum for the class of material being tested.CSA G164-18 pdf download.