With the increasing advancements around the world in the welding area, new methods and welding techniques are being introduced day after day. Corten steel welding is a similar technique that was introduced to weld steel.
Well, you will find many ways when it comes to welding steel but only a few of them can give you the result you want. So what if you chose a certain welding method and the results are not what you expected?
Do not consider it a failure, because you might have made mistakes in selecting the welding method or equipment. Now the best thing you can do is to avoid making such mistakes while welding next time.
Corten steel welding
Weathering steel is often named corten. This type of steel gives nice and smooth welding results and is resistant to rust.
Also, it contains chromium, copper, and nickel alloys that increase the capability of corten steel to make it weather resistant. It is one of the main reasons that corten steel is recommended to be used in construction and structural purposes.
Why use corten steel?
Now, to better understand the concept of corten steel welding, first of all, we need to know the mechanical properties and capabilities of corten steel.
Highly resistant to rust
The most important fact about corten steel is that it is highly resistant to rust. Not only that, it is capable of altering the way rust can affect the material’s surface. Also, the presence of alloys like nickel and chromium makes it more resistant to rust.
The layer of dried rust
All the above-mentioned factors result in a beautiful patina by drying the rust quickly. The rust is dried on the surface of the metal forming a thick layer on the surface. This rust layer serves as a paint layer and protects the material instead of weakening the structure of the metal.
The thick coating of the rust layer protects the inner material from severe weather conditions. In addition, the structure becomes strong and capable of bearing heavy loads.
Besides giving strength and long life to the metal, it can effectively change the appearance of the structure by making it more attractive with time.
Most architects and sculptors recommend and prefer this corten steel welding because it gives a natural rusty appearance to the structure. It gives a special charm and aesthetics to the structure over time.
How to weld corten steel?
Now that we have discussed the importance and useability of corten steel, here we will discuss different welding techniques we can use to weld corten steel.
The process is very similar to the tod mild steel welding. But the only difference is that you are required to use a filler wire here during welding corten steel.
Three processes which are used worldwide to weld corten steel are:
Corten steel welding using the MIG welding technique
The basic way to do MIG welding is using an electric arc and filler material to join two metal pieces together. The metal pieces which are to be connected are joined together by making the joints contact each other.
Then the filler material is placed between the joints by melting it using the heat produced by the welding arc. Here the key point is to select the filler material carefully to get the desired color by optimizing it.
E7018 MIG welding wires
For thinner metal plates, E7018 MIG welding wires are recommended because they provide enough dilution to the plates by joining them effectively.
And if you are working on the joints where you are required to do a double passing of filler material, then you need to choose the filler material accordingly.
Corten steel welding using the TIG welding technique
We are going to use the same procedure we use to weld mild steel here as well. But in addition to using a filler material, a tungsten electrode with used along with it while welding the weathering steel.
You need to have a sharper electrode of filler material because we have to direct the heat towards the seam of the welding area. Here the key point of the procedure is to direct heat correctly in the right direction. It is opposite to the case where we weld aluminum.
During aluminum welding, heat is dissipated more quickly in all directions. Whereas in the case of corten steel welding, the heat should be pointed properly in the right direction to make sure the weld is done properly.
Things to remember during welding
The thickness of electrodes matters while welding electrodes and it depends on the thickness of the metal. The diameter and size of the electrode should be half the size of the metal you are welding.
Here you need to work with a direct current with a negative charge on the electrode by setting the required polarity before welding.
Selecting filler material
If you are selecting the filler wire seriously, then believe me it is going to cause a problem for you. In case of selecting the wrong material, it will decrease the tensile strength of the weld and the corten steel dramatically. Not only that but also its corrosion resistance will also decrease to a deficient level.
Moreover, all these things can cause drastic changes when you are working on a big project that requires a lot of strength and care for example building bridges.
Corten steel welding using Arc welding technique
The main part of this procedure is the correct use of electric arc. All you need to do is to produce heat with the welding arc to melt the filler material in the joints of metal that need to be welded together.
It can be a little bothersome for you because you have to handle the filler material and arc simultaneously in each hand.
However, this method is quite flexible because you can weld metals with any thickness easily. In addition, you don’t have to make adjustments and change material every time you are welding metal with a different thickness.
Selecting the right filler material
We have been emphasizing a lot during our whole discussion about how important is the role of selecting the right filler material.
Properties to consider while buying filler material
While you are going to choose the filler material for your welding process, you should keep in mind the following things:
- Toughness and level of strength
- Size required for welding
- Welding position
- Consider if you want to get the painted filler material or without paint
- The Colour should be matching
- Any other requirement if exists
Above all the properties, the degree of strength and toughness is the most important one. Tensile strength of approximately 50 KSI to 70 KSI is required to weld corten steel in everyday applications.
However, this strength can vary depending on the type of application you are working on. In such cases, tensile strength can increase up to 100 TSI and more.
Specifications and welding codes
With the choice of the right filler material, you also need to select the type of weathering steel carefully. Corten steel comes in different welding codes having different specifications.
Please follow the technical instructions and design requirements of the project and the type of corten steel you are working with. With different tensile strengths, corten steels differ in their mechanical properties.
Hence, when choosing the filler material and the type of corten steel you want, a decision must be made after a complete evaluation of the material. You need to think wisely about the placement of filler material.
In case any area is open and not covered properly with the filler material, corrosion can occur. Also, the resulting weld will be weakened in strength and will not last longer than expected.
Now we will conclude all this in a few lines. All we can say is that you can use corten steel to get results with a strong base and aesthetically pleasing appearance.
However, we are not saying that it is the only solution by which you can get such a result. No doubt there are other methods as well. They can give you the same result but the wise thing to do is to decide between them according to your material and circumstances.