We often hear students asking the question, “Is galvanized steel magnetic?” Most students are not sure about it because there are reasons for it to be magnetic as well as non-magnetic.
So, it is critical to answer this question with proper reasoning so that they can understand it properly. To answer this question, first, we need to know what galvanized steel is. It is nothing but steel with a coating of zinc around it. So, does a layer of zinc over steel make it non-magnetic?
In this article, we will try to find the answer to this question and other facts about galvanized steel.
So, is galvanized steel magnetic? Yes, Galvanized steel is magnetic because galvanization of steel does not affect the magnetic behavior of steel. Galvanization is the process of coating of zinc layer on the steel.
We can surely declare yes, galvanized steel is magnetic. As we are aware that steel is magnetic, and galvanized steel is coated with a thin layer of zinc.
But many are confused as zinc is a non-magnetic element, so why galvanized steel is still magnetic?
This doubt should be clear that there is no impact on the magnetic behavior of steel by putting zinc coating on steel.
We must understand that adding a thin layer of zinc does not change the property of steel. Since iron is a strong magnetic element, so its properties do not change because of the zinc coating.
So, galvanized steel remains magnetic. However, some better-quality steel that has a higher percentage of nickel and chromium are not magnetic.
Why Steel Remains Magnetic, Even After Galvanized?
Iron is a magnetic metal, and steel is an alloy of iron. It consists of a very small quantity of carbon. The percentage of carbon varies from 0.45% to 2% depending on the amount of carbon added to it.
The standard steel that contains only iron and carbon is magnetic. Galvanized steel contains a thin layer of zinc around it. The layer of zinc does not act as a barrier to magnetism.
It is because here the properties of steel do not change.
However, if you talk about other types of steel, they are produced by mixing materials like silicon, manganese, nickel, chromium, copper, aluminum, etc.
Adding other metals to molten steel change its properties. So, these alloys don’t have the properties of carbon steel.
So, adding these metals make steel non-magnetic.
Why is Galvanized Steel Ferromagnetic?
Before we explore the answer to this question, let us know which are ferromagnetic elements. The elements which are strongly magnetized and can be converted into a magnet permanently are called ferromagnetic.
As we know common steel or carbon steel is an alloy of iron and carbon. Galvanized steel is formed by applying a thin layer of zinc over the steel.
The physical properties of steel are almost the same as iron though the chemical properties vary.
So, knowing about iron will help us understand the magnetic properties of galvanized steel.
We know iron is metal as it belongs to group 8 and the first transition series in the periodic table.
The symbol of iron is “Fe” and its atomic number is 26. The electronic configuration of iron is [Ar] 3d6 4s2. It has four unpaired electrons and two electrons in the valence shell.
The magnetic property of an element depends on the number of unpaired electrons. The magnetic domains in iron have magnetic dipoles.
These domains are the building block of a magnetic material. They have magnetic dipoles that get parallel when the iron is placed in a magnetic field.
If you remove the external magnetic field, iron still remains magnetized. So, iron gets permanently magnetized.
As you know the elements which are strongly magnetic and can be converted into magnet permanently are ferromagnetic.
This is the reason why iron is ferromagnetic and so is galvanized steel.
Why is Galvanized Steel magnetic but Stainless Steel not?
As you are aware that galvanizing steel means applying a coating of zinc on the steel. So, it does not change the basic properties of the steel, and that is why the magnetic property is not changed.
On the other hand, stainless steel is an alloy of steel and chromium (minimum 10.5% by weight). It is produced by mixing molten steel and chromium, so the properties of steel completely change.
Here steel loses its properties, and a new matter is formed. It is the reason why galvanized steel is magnetic, but stainless steel is not.
How is Galvanized Steel Produced?
There are mainly two ways by which galvanized steel is produced. In this section, we will know both the process of galvanization in detail and what are the differences between them.
1. Hot-dip galvanizing – It is the process of galvanization, where steel is dipped into hot and molten zinc and taken out a few seconds.
Then it is allowed to cool down for some time. Once the molten zinc cools down, we can see a layer of zinc covered around the steel, and it is ready to be used for various purposes.
When iron is dipped in molten zinc, it forms a layer of zinc carbonate over steel which is corrosion resistant.
The hot zinc reacts with oxygen to form zinc oxide (ZnO), which later reacts with carbon dioxide to form the protective layer of zinc carbonate (ZbCO3)
2. Zinc-Plating or Electro-Galvanizing – It is a chemical process where a fine layer of zinc is applied to the steel by using the electroplating method.
In this process, a zinc salt solution is used as an electrolyte, and a piece of zinc is used as an anode while steel is used as a cathode.
During the electrolyte process, zinc starts depositing on the steel gradually while an equal amount of zinc from anode goes into the solution.
The process is time-consuming, and it requires some knowledge of the electrolysis process to perform zinc-plating.
The biggest advantage of electro galvanizing is a uniform layer of zinc deposited over the steel. Moreover, the electroplated steel obtained in this process is brighter and aesthetically appealing.
Know More About Galvanized Steel
Properties of Galvanized Steel
1. As we all know galvanized steel is nothing but steel that has a layer of zinc around it. Zinc is less reactive than iron, so it does not corrode as much as iron does.
Adding a layer of zinc protects the steel from oxidation and increases its life span.
2. Galvanized steel is as strong as carbon steel, but it lasts longer than that. It is an alternative to stainless steel.
3. Galvanized steel is cheaper than stainless steel because it does not require steel and iron to be melt to produce it.
A layer of zinc can be added to carbon steel by dipping the steel material in molten zinc. It can be repeated depending on the usage of the galvanized steel.
4. Galvanized steel can be recycled like any other type of steel.
5. The carbon steel does not look shiny, but adding a layer of zinc makes it look shinier.
In this article, we have looked at manufacturing, usage of galvanized steel, and the most importantly its properties.
Now we know that galvanization of steel does not change its properties, especially the magnetic effect. Despite galvanization, steel remains magnetic, and there is no impact on that. If the steel was non-magnetic before galvanization (in the case of steel alloys), it remains so after that.
So, we can conclude that galvanization does not affect the magnetic properties of steel. We have also talked about the product usage, and benefit of galvanized steel. We hope you find the article useful.