A Look into the Process of Galvanizing Steel Pipes

by Jessica

Posted on 12 August, 2022 at 2:20 PM


  • Metal Preparation
  • Dipping Phase into Molten Zinc
  • Cooling, Finishing, and Drying
  • Quality Control

Numerous practical uses, such as water transportation, farming, telephony, and plumbing, call for the usage of galvanised iron pipes. Due to its durability and resistance to corrosion, galvanised iron pipes are good for use both inside and outside. Do you ever wonder how these things are manufactured, though? These steel pipes are extremely durable and popular for engineering and construction projects all around the world because of the galvanising process. We'll be talking about the same thing today! Here is a more thorough explanation of how galvanised iron pipes are created.

Metal Preparation

The iron pipes are thoroughly prepared on the surface before anything else. The base metal must go through a number of procedures before it can be galvanised. All of this makes sure the iron is prepared for the following step. Galvanized iron pipes are typically surface-prepared as follows:

The steel is first cleaned with a chemical solution, a corrosive substance that gets rid of all the oil, grease, and dust.

The iron pipe is then pickled after the chemical solution has been removed by water. Pickling is a method for cleaning metal surfaces that is used to get rid of rust, scale, impurities, and stains from ferrous metals.

Mill scale, or the flaky surface of hot-rolled steel as it is more commonly known, is removed by pickling the iron pipe in an acidic solution.

Once the pickling solution has been removed, the iron pipe won't need to be fluxed. Zinc ammonium chloride is frequently added to the base metal in order to stop oxidation of the cleaned surface.

Dipping Phase into Molten Zinc

All phases of the galvanising process are crucial, but this particular step and method are what make it so well-liked. The molten zinc bath that surrounds the iron pipes is at a temperature of around 449 degrees Celsius, or 840 degrees Fahrenheit. On the surface of the base metal in this place, it will produce a substantial and durable coating.

What are its uses? The compound called zinc keeps water and oxygen from penetrating through to the basic metal beneath. Additionally, it makes a considerable difference in the metal's ability to resist rust and corrosion. Zinc functions as a sacrificial anode when it comes into touch with the outer layer due to friction and dust.

To make the molten zinc bath more liquid and to limit the amount of zinc on the dipped iron pipe, some producers add lead. Additionally, it helps to stop floating dross.

Cold-dipped galvanising, in which the base metal is only coated with zinc-rich paint, may be used by some companies. However, hot-dipped galvanising is currently the method that is most frequently utilised. It has been demonstrated since 1742 that it provides a superior, more durable, and maintenance-free coating for metals.

Cooling, Finishing, and Drying

It is now time for the galvanised iron pipes to cool after the zinc dipping procedure. In order to cool quickly and avoid unintended consequences of the recently created coating reacting with their surroundings, galvanised iron pipes are typically cooled in a quench tank.

Quality Control

All manufactured goods are subject to a tight enforcement of quality requirements. Here, the final product requirements for the galvanised iron pipes are tested.

Since each manufacturer uses a different approach and set of procedures to guarantee the calibre and standards of galvanised iron pipes, there is no one-size-fits-all approach to quality control.

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