A Better Version of Hot Dip Galvanized ?

By | August 1, 2014

A Better Version of Hot Dip Galvanized Coated Steel?

Zinc-Al-Mg Hot Dip Galvanized Coated Steel.

As the industrial world look into ways on how to protect against corrosion, there has been little education on how the coating industry has made progress in this field. Which explain the reason why in most major projects such as infrastructure, process industry, oil and gas and even building industries still maintaining the specification of the Normal Hot Dip Galvanized Steel requirement with average micron of 45-55 micron thickness coating.

Even the Strangest things happen when manufacturer are told that their products is not acceptable and was asked to change to lower grade / much inferior Normal Hot Dip Galvanized Coated Steel from  Zinc-Al-Mg Hot Dip Galvanized Steel. Of Course even with the more superior coating protection of Zinc-Al-Mg Hot Dip Galvanized Steel, there is a huge disadvantage when the materials need to be welded or exposed to hot works which may damaged the coating on the steel. 

Of which Post Hot Dip Galvanized Steel has a better protection when applied after the materials are welded or exposed to hot works.

For a Better Understanding on the more Superior Protection of Zinc-Al-Mg Hot Dip Galvanized Steel, Lets Look at the Chart Below comparing the Coating Reduction over the years between the different type of Hot Dip Galvanizing Process including the Normal Post Hot Dip Galvanized Process:

Reference taken from: http://www.nhsinosource.com/products-14/eng/engproducts-14.htm

As you can see that as the years goes by the Coating reduction between the Normal Hot Dip Galvanized and Zinc-Al-Mg Hot Dip Galvanized goes even wider. This shows that over time Zinc-Al-Mg Hot Dip Galvanized Steel provide much better corrosion protection over the former Hot Dip Galvanized Process.

Below is the table showing the Different Advantages and Disadvantages of the Normal Post Hot Dip Galvanized Process over Zinc-Al-Mg Hot Dip Galvanized Material:

Description Normal Post Hot Dip Galvanized Zinc-Al-Mg Hot Dip Galvanized
Coating Thickness Due to its Batch HDG Process, it is Natural that the Coating Thickness is irregulars through out averaging 45 – 65 Microns for Steel Thickness of 2 – 2.5 mm Automatic Continuous Coating Line, the ability to have a consistent Coating thickness and better Coating Quality through out.
Visual Since Post HDG Relied a lot on manual operations and the skill of the operations, Visual may be inconsistent through out the Product Surfaces. Problems such as Zinc Ash, Spots and rough surfaces and inconsistent spangles may be found in this process. Consistent Visual and Better Quality Visual Appearance..



Recent Studies found that No Spangles surface of HDG provide a better protection against white rust, although White Rust does not have any significant affect the quality of the Coating.

Corrosion Protection Inferior Corrosion Protection with thicker Coating mass Superior Corrosion Protection with thinner coating mass.
Welding or Other Hot work Process This is Most Suitable to use, because the Hot Dip Process is done Post Fabrication Work. No Damage to the Coating as it is the last process. Not Suitable



The Coating will be damaged due to the heat and after fabrication, repair to the coating must be done by cold galvanizing or Painting over the damage area with Zinc Paint which cause visual deterioration.

Bending and Cutting (excl Hot Cutting) Significant reduction of Coating Protection. After Hot Dip Galvanized, there should not be any more process done to the Material



Cracks and Peeling off happens when the material is bended after Hot Dip Process 

Excellent Protection over Bended Area and Over Cut areas, the Coating can Leached to the Cut Area and give protection over the cut areas.



HDG over Bended Part

HDG Over Cut Areas

Formed Part Significant Reduction of Coating Protection, especially when the Forming is Done after the Hot Dip Galvanized Process is done.



Cracks and Peeling off happens when the material is formed after Hot Dip Proces

Excellent Protection over Formed Area.

HDG over Formed Area

Wastage Zinc Coated is Only applied to Products and not wastage materials More Wastage on the Coated Material as Material are Pre-coated Prior to Production
Cost over Transport and Handling Higher as there is additional Handling needed to and fro the Hot Dip Galvanizing Process Lower as Materials are shipped pre-coated.


PT Trias Indra Saputra has now started to provide Channel Raceway, Cable Support System and Electrical Switchboard Enclosure in ZAM and POSMAC High Corrosion Resistance Steel – (Zinc-Al-Mg Hot Dip Galvanized Steel)

Find Out More by Contacting Us Here.

To Read More:

1. Understanding More on Comparison of Hot Dip Galvanized Process 

2. http://scitation.aip.org/content/aip/proceeding/aipcp/10.1063/1.3589776

Zinc-Al-Mg Hot Dip Galvanized Solution may provide a better solution to your Corrosion Protection needs with much economic value than materials such as stainless steel or aluminium.

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