Hot dip galvanizing provides a long and quality protection, by excellence, for the profiles and sub-assemblies of steel and cast iron.
The main advantage of spin-galvanizing of small parts is that it offers, due to new technology, a very good process control and at the quality standars:
SR EN ISO 10684 – Assembly elements. Hot dip galvanizing coatings.
Pieces designed for galvanizing are subject to the following technological stages of chemical preparation:
Degreasing: The parts are treated with a solution of phosphoric acid in order to remove any oil and other impurities.
Pickling: The parts are treated by immersion in a bath with cold acids solution, in order to clean them of any rust.
Washing: It is performed to remove any traces of acid from the surfaces.
Fluxing: It is performed in a bath of hot water and ammonium chloride to delay the oxidation.
Drying: It is used to dry the parts and prepare them for the immersion in a molten zinc bath.
Galvanizing: It takes place by immersion in molten zinc, at 450°C, for a few minutes, depending on the type of the material and required coating thickness.
Centrifugation: This step is performed when galvanizing small products: screws, nuts, bolts, small holders, etc. The basket with galvanized parts is placed in a special machine and is centrifuged for a few seconds at high speed. All zinc excess is removed by the centrifugal force, resulting in a smooth and lump-free coating. The material surrounded by frames, after galvanizing, is blown with compressed air, so that the zinc layer that is still melted is distributed evenly.
Cooling: The pieces are cooled in a bath of cold water and are ready to be packed.
Parts thet are beeing designed for centrifugal galvanizing can weigh between 0,1kg and 3kg, with a maximun lengh of 500mm.