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Last edited 01 Jun 2022

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Hot dipped galvanized steel coil

1 Introduction
2 How does the hot-dipped galvanizing (HDG) process work?
3 Difference between hot-dip galvanizing and cold galvanizing
4 Related articles on Designing Buildings Wiki

[edit] Introduction

One of the most popular forms of galvanized steel bought from coils is hot dipped.

This means that there will likely be a zinc layer on the outside of the sheets that will act as a barrier, separating the galvanized steel from outer elements. It is then far more durable than common steel sheets. Essentially, it is positioned in a molten bath of pure zinc, ultimately causing chemical changes that will make it much more durable.

[edit] How does the hot-dipped galvanizing (HDG) process work?

This technique, also called HDG, is now a lot more common. Galvanizing is basically the process of adding a coating on any base metal for the purpose of increasing corrosion resistance and durability. Hot-dip galvanizing is a form of galvanization. It is the process of coating iron and steel with zinc. That is, the surface of the base metal is coated with a zinc layer by immersing the metal in a bath of molten zinc at a temperature of around 450 °C (842 °F).

Galvanized steel is widely used in applications where corrosion resistance is needed. But its cost is much lower than the cost of stainless steel.

[edit] Difference between hot-dip galvanizing and cold galvanizing

In hot-dip galvanization, the base metal is dipped into a bath of molten zinc at 450 °C. The zinc coating is thicker. Cold galvanizing is where the zinc salt solution is plated to the base metal by the process of electrolysis. This process does not involve any kind of heating. During the process of cold galvanizing, the zinc is deposited on the base metal at the anode which is thin and may not be uniform. As it is conducted in a wet environment, the coating layer of zinc can come off quite easily.

Generally, materials that are simply galvanized may last at least 30 years. The addition of zinc on the outside, as well as the metallurgical process that will occur, will allow it to last many extra decades. It's also possible to get similar results by having a zinc-iron alloy instead.