Design of Structures for Hot Dip Galvanizing
Hot Dip Galvanizing of Concrete Reinforcement Bars
This is completely eliminated by using hot dip galvanized bars in place of epoxy coated bars. Hot dip galvanizing can be carried out even after cutting and bending of the steel form work.
Note: By double end dipping method, up to 12mtr long articles can be dipped (with prior consultation)
Duplex System Of Coating
Rinsing Tank-8mtr long x 1.2 mtr wide x 1.2 mtr deep – 2Nos
Flux Tanks-8mtr long x 1.2 mtr wide x 1.2 mtr deep – 1Nos
Hot Dip Galvanizing Procedure
- Hot Dip Galvanizing is the process of coating Iron and Steel articles with zinc for protection against corrosion by dipping the articles in molten zinc at a temperature of 455+ 50c.
- Pickling: steel material is immersed into HCL Solution tank for approximately 1 to 2 hours depending upon the surface condition, to remove all rust, mill scales, dirt, etc.
- Rinsing: rinsing the steel in fresh water to remove traces of HCL
- Fluxing: The clean steel is immersed in a flux bath, consisting of zinc ammonium chloride solution to wet the steel surface and prevent oxidation before galvanizing process.
- Drying: The steel materials are spread over a heating platform to remove moisture content and to facilitate the flux to form a thin film coating over the steel and also to pre heat the steel before dipping.
- Dipping: The steel materials are then dipped into molten zinc bath maintained at a temperature of 455+ 50c. After the reaction is over the surface of the bath is skimmed and the materials are slowly withdrawn from the bath. Time of dipping depends on the thickness, shape of the steel, etc.
- Quenching: The galvanized materials are either air cooled or quenched in a water bath for cooling.
- Recovery and final inspection: Excess zinc on the material, lumps, spikes, etc. are removed by sanding, filing, etc.
- Coating thickness is measured with a calibrated elecometer. Materials are bundled and stacked in the yard for dispatched.