Flux and fluxing bath for hot dip galvanization, process for the hot dip galvanization of an iron or steel article

摘要

The present invention generally relates to a flux for hot dip galvanization comprising from: 36 to 80 wt. % (percent by weight) of zinc chloride (ZnCl2); 8 to 62 wt. % of ammonium chloride (NH4C); from 2.0 to 10 wt. % of a least one of the following compounds: NiCl2, MnCl2 or a mixture thereof. The invention further relates to a fluxing bath, a process for the hot dip galvanization of an iron or steel article as well as to the use of said flux.

主权项

1. A process for hot dip galvanization of an iron or steel article comprising:
a) degreasing the article in a degreasing bath; b) rinsing the article; c) pickling the article; d) rinsing the article; e) treating the article in a fluxing bath comprising between 200 and 700 g/l of the flux, said flux comprising on a weight percent basis: 36 to 60 wt. % zinc chloride (ZnCl2), 8 to 62 wt. % ammonium chloride (NH4Cl), 2.0 to 10 wt. % NiCl2, MnCl2 or a mixture thereof, wherein the total of the above salts is 100% by weight of said flux; f) drying the article or letting the article dry in the ambient air; g) dipping the article in a hot dip galvanizing bath of zinc-200-500 ppm aluminium alloys, or of common pure zinc to form a metal coating thereon; and h) cooling the article in water based solution or with air.