You might have been to a job where a steel pipe got damaged, and you had to weld it. But did you know that you can’t easily weld aluminum to stainless steel?
Even some of the most experienced welders face this problem, especially when they are new to welding.
Welding is the process of bonding two pieces of metal together with heat and pressure. Aluminum and stainless steel are not commonly welded together because doing so will cause fatigue problems in the welds over time.
But with the right equipment, techniques, and procedure, you can weld aluminum to stainless steel, but it is quite complicated as compared to other welding methods.
But don’t worry. In this article, I will guide you on whether can you weld aluminum to stainless steel and how?
Can You Weld Aluminum To Stainless Steel?
You can weld aluminum to stainless steel, but it’s not recommended for structural purposes. Aluminum is an excellent conductor of heat, which means that any gap between the two metals will cause uneven heating and can lead to cracking or warping. If you’re welding aluminum to stainless steel, be sure to use filler rods with a lower melting point than the base metal.
The reason is that aluminum has a low melting point, and the heat from welding will cause it to melt. This can happen even if you are using a very low-power welder and keeping the temperature of the metal at or below its melting point.
Stainless steel has a high melting point and is not affected by heat as much as aluminum, so it will not melt when being welded on by itself.
However, because of this high melting point, I recommend using a stronger welder than you would normally use for aluminum in order for the stainless steel not to crack underneath the aluminum layer being applied.
It’s not enough! Keep reading the article to know more about welding aluminum to stainless steel.
Major Differences Between Aluminum & Stainless Steel
Aluminum and stainless steel are both popular materials that are used in surgical instruments, but they have some key differences. The table below highlights the major differences between these two metals.
| Aluminum | Stainless Steel |
| Aluminum heats quickly because of higher thermal conductivity and evenly, as well as cools down quickly, meaning it’s great for cooking at high temperatures. | Stainless steel has a lower thermal conductivity than aluminum, which means it can take longer to heat up. |
| Aluminum has a melting point of 1,220°C (2,000°F). | Stainless steel has a melting point of 1,371°C (2,600°F). |
| When service temperature minimizes, aluminum strength increases. | When service temperature minimizes, stainless steel becomes brittle. |
| For aluminum, hydrogen creates the issues of porosity and bubbles when solids. | For stainless steel, hydrogen is not favorable because of creating cracking issues. |
| Aluminum is lighter than steel, which makes it a better choice for some applications. | Stainless steel is less likely to rust and can be polished. |
Reason to Weld Aluminum to Stainless Steel
Welding aluminum to steel is a common practice in the automotive industry. Steel is a strong, durable material that can be used for a wide variety of applications. However, it does not conduct electricity well and is therefore not ideal for use in automobiles.
Aluminum, on the other hand, conducts electricity very well but is not as strong as steel. When we weld these materials together, we create a stronger alloy that has both properties: an electrical conductor and durability.
Welding aluminum to stainless steel or other types of metals is also an important process in manufacturing. This allows us to create strong alloys by combining different metals with each other.
The density of aluminum is much lower compared to steel, so if you are welding aluminum to steel, you will have to take care that the weld does not slag when you transport it.
This can be done by using less filler material or by using a low melting point filler metal like aluminum which is a lot cheaper than steel.
So, it is not easy as you just think about welding aluminum to stainless steel. Even sometimes, traditional welding procedures cannot help in welding aluminum to steel.
Also See: Don’t Make this Mistake Welding Stainless to Carbon Steel
Why is it Not Easy to Weld Aluminum to Stainless Steel?
The reason why it is not easy to weld aluminum to stainless steel is because of the different melting points of the elements. Aluminum melts at about 1,220°F, and stainless steel at about 2,400°F.
If the two materials are placed in contact with each other for more than a few seconds, an oxide layer will form that prevents molten material from reaching the base metal.
It can be difficult to reach a temperature that’s hot enough for both to melt at the same time.
It is difficult to weld aluminum to stainless steel because they are dissimilar metals. These two types of metal have different properties and chemical components, which means that they are not likely to bond together in the same way that similarly structured metals do.
Why is TIG Welding not Suitable for Welding Aluminum to Stainless Steel?
The reason TIG welding isn’t suitable for welding aluminum to stainless steel is due to the fact that aluminum melts at a much lower temperature than stainless steel does.
Because of this, it’s very difficult to weld aluminum and stainless steel together using TIG welding.
The reason for this is that TIG welding uses an arc that is made between the electrode and the metal being welded.
This arc generates enough heat to melt the two pieces of metal together but not enough heat to cause any damage or discoloration on the surface of either piece of metal.
When doing TIG welding, you have to be very careful about the amount of heat flowing through your workpiece because too much heat can cause a fire or even an explosion.
I suggest you carefully control the arc current so that it doesn’t get too hot or melt through your workpiece.
If you try to use TIG welding with aluminum and stainless steel, you’ll probably end up melting your material before it can even fuse together properly!
How to Weld Aluminum to Stainless Steel? 4 Different Ways
I will explain to you the four most important ways of welding aluminum to stainless steel in detail:
1. Bimetallic Transition Way:
The bimetallic transition is a phenomenon that occurs when two metals are heated to their melting point and then cooled in the presence of each other. When this happens, a thin layer of one metal will form on the surface of the other.
This layer is called a “transition zone.” Once this layer has formed, the two metals can be joined together by welding.
When you weld aluminum to stainless steel, you must first make sure that both materials have been cleaned properly and then heated to their respective melting points.
After they have been heated, they should be allowed to cool slowly in order to form a transition zone between them. If this step is skipped or done incorrectly, there may not be enough heat present when you try to weld them together later on!
2. Brazing Way:
Brazing is another method of joining two metals that are similar in melting temperature. It is a good way to join aluminum and stainless steel, as they both have low melting points and can be joined by brazing with a silver or copper filler metal.
The process involves applying heat to the joint, applying flux, then placing the filler metal onto the molten surface.
The molten surface should be kept at a high enough temperature for long enough for the filler metal to melt and flow into all areas where it is needed.
Once you have finished this process, you can remove your torch from the joint and allow it to cool slowly without disturbing it too much until it has reached room temperature before removing any excess flux or removing the brazing rod from inside of your joint (if applicable).
During my welding projects of welding aluminum to stainless steel, I want to personally prefer the brazing method.
3. Bonding Way:
Bonding is the best option for people who want to weld small quantities of aluminum and stainless steel together. It involves placing a thin layer of nickel or copper between the two materials to create a bond between them.
I advise you to apply on such metals that are completely flat and clean, with no crevices or gaps where water could get trapped during the welding process.
4. Aluminizing Way:
Aluminizing is a more permanent solution for joining aluminum and stainless steel together because it creates an alloy that won’t corrode like other types of bonding materials might over time.
It involves electroplating both metals with aluminum oxide, which gives them similar properties like corrosion resistance without sacrificing their unique strengths (aluminum’s lightweight or stainless steel’s strength).
The Difference Between Brazing And Soldering Aluminum
Both brazing and soldering are joining processes, which means that they’re used to join two pieces of metal together.
The difference between the two is that brazing uses a filler metal (a metal lower on the Mohs scale than either the base or filler metal), and soldering uses a liquid metal.
Brazing can be used to join a wide variety of different metals—including aluminum—because it involves melting both the base metal and the filler material into one solid object.
Soldering is only suitable for specific types of composition, like eutectic alloys or other compounds that can be melted at low temperatures through chemical reactions.
In order to properly perform either operation, you’ll need special equipment such as an induction welder or gas torch, depending on what kind of heat source you choose.
What do You need to Know About Welding Stainless Steel to Silicone Bronze?
When you’re welding stainless steel to silicone bronze, it’s important to know that silicone bronze is a copper-based alloy material. This means that it’s softer than stainless steel and will require a filler rod when welding.
You’ll also need to use a special electrode on your welder in order to get the job done right. In addition, you’ll need to use an arc welding technique called pulsed wave current in order for this process to work properly.
When you’re welding silicone bronze, it’s important to know that bronze is a copper-based alloy material. This means that it’s softer than stainless steel and will require a filler rod when welding.
You’ll also need to use a special electrode on your welder in order to get the job done right.
In addition, you’ll need to use an arc welding technique called pulsed wave current in order for this process to work properly.
Final Words!
When it comes to welding metal, the commonly asked question is: “Can you weld aluminum to stainless steel?” The short answer: while they don’t mix chemically, they can be joined together when the right precautions are taken.
In the above article, I have guided you about famous ways to weld aluminum to stainless steel.
Also, I told you above that it’s not easy to weld aluminum to steel because you must have to face some difficulties if you want to go for such a project.
FAQs:
Does aluminum stick to stainless steel?
Aluminum, like other non-ferrous metals, does not stick easily to stainless steel. This is because it does not have strong magnetic properties itself. However, magnetism can be used to hold aluminum in place on non-magnetic stainless steel surfaces.
Can you weld metal and aluminum together?
Just like metal, aluminum can be welded. In fact, aluminum is often used in the welding process because it does not shatter in high-heat environments and is easy to fabricate. However, when aluminum joins with other materials, such as stainless steel or copper, it will often crack due to the differences in melting temperatures. One way around this problem is to add a filler metal that melts at a lower temperature than both the base metal and the desired joining metal.
What welder is best for welding aluminum and stainless steel?
The best welder for welding both stainless steel and aluminum is the MIG welder Aluminum 140. Hobart handler 140 welder is a great welder for general-purpose stick welding projects and is also perfect for aluminum. This MIG welder features pulse control which allows you to increase or decrease your arc force on the fly.
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