Galvanizing methods

Galvanizing methods or Galva-coat methods are including : Electro Galvanizing, Hot Dipped Galvanizing, Mechanical Coating , Zinc Spraying ( Metallizing ) , Zinc Dust Painting ¹ .
But the most common of them are :

1- " Electro Galvanizing " or " Cold Galvanizing " , is a process which zinc coatings are obtained on various pieces such as a coil or an uncoiled sheet by electrolysis of zinc salts in an aqueous solution . In the majority of cases acid electrolytes are used, but they may also
be basic electrolytes, with or without cyanides. In this methods the thickness of zinc coating layer is less than the hop dip galvanizing methods and usually used for indoors applications .

2- " Hot Dipped Galvanizing ", which consists of passing the continuous length of sheet, wire, rod, or shape through immersion in a molten bath which is combinations of Zn, Mn, Sn, Ni, Mo, Cu, Ti, Co, Al, Si, C, P , followed by an air stream "wipe" that controls the thickness of zinc finish .The Metallurgists usually use two different approaches for hot dip Galvanizing those are called , Noncontiguous hot dip galvanizing approach and Continuous hot dip galvanizing approach:

1-2- Non-continuous Hot Dip Galvanizing : In this mechanism ,cut sheets enter to the production line and after passing pretreatment, they enter to the molten zinc bath independently .

  2-2- Continuous Hot Dip Galvanizing : Continuous galvanizing line or CGL is the processes by which zinc coatings are obtained on products such as coils ,whereby these products are continuously passed through a molten zinc bath .

 

 

Comparing Galvanizing Methods

Seven Diamonds has been applied the " Continuous Hot Dip Galvanizing Technique " in the galvanizing process .

  1- Other galvanizing methods :

  Mechanical Plating : Small iron and steel parts maybe coated by drum tumbling with a mixture of proprietary promoter chemicals , zinc powder and glass beads. After cleaning the parts, which are usually limited in size to about 200-300 mm ,and weighing less than 0.5 Kg, are flash copper coated and loaded into a plating barrel .The barrel is then filled with chemical glass beads and zinc powder and then tumbling action causes of the beads to peen the zinc powder onto the parts .

  Zinc Spraying (Metallizing ) : Zinc spraying is accomplished by feeding zinc I either wire or powder form into a heated gun ,where it is melted and sprayed onto the part to be coated using combustion gases and/or auxiliary compressed air to provide the necessary velocity .

  Zinc Dust Painting : Zinc-rich paints contain 92-95% metallic zinc in the film of paint after it dries . The paints are usually applied by brushing or spraying onto steel that has been cleaned by sand lasting.