You are working on a steel project which calls for galvanised steel and you want to make sure the steel you purchased is galvanised. How to tell if steel is galvanised? Galvanised steel usually appears bright in color, but you cannot be 100% sure just by its appearance.
Though it is difficult to test whether steel is galvanised, there are a few methods which can identify the presence of a zinc coating over the steel surface.
Thickness measurement
This is a simple and non-destructive way to identify the presence of a coating material on steel. Use a magnetic thickness gauge to measure the thickness of the coating over the steel surface. This method can indeed confirm whether a coating is present on the steel, yet it doesn’t say what coating it is.
Once you confirm there is a coating on the steel surface, you may be able to use visual clues to identify if it is a zinc coating. For example, if blisters are present, it may be a paint. If the surface has the typical traits of a galvanised material, it may be safe to conclude that it is galvanised. Yet, you cannot be 100% sure if it is a zinc coating.
Laboratory testing
In laboratory testing, a sample of the coating is tested to identify the materials present in it. A photograph of the cross section of the material is also taken to identify the different layers present. Laboratory testing is the only way to be 100% sure whether a piece of steel is galvanised. Yet, it has two drawbacks. It is a slow process and it is destructive which means you may not be able to use a finished fabrication for testing.
Salt water testing
If you don’t want to use the above two methods, there is a simple and easy method to identify whether the steel has been galvanised.
Prepare a solution of 3 parts salt to 1 part water. Dip a cloth in the solution and use this to wipe the steel surface. Check the steel after 24 hours. If it is a non-galvanised steel, it will rust and if it is galvanised, it won’t rust.
‘How to tell if steel is galvanised’ is not an easy question to answer. Also, testing every piece of steel you buy is not a practical solution. That is why, it is important to always buy steel from a reputed and trust-worthy supplier with plenty of experience in the steel industry.
Melsteel has been servicing the Melbourne steel industry for more than 30 years. We provide high quality steel and fabricate it to suit your requirements. We also deliver, install and erect it at your project location. Buy your steel online or contact us today to speak to one of our customer service representatives to know more!
