Dear friend Md Marjan Jahan Tazin

Hey there, fellow researcher! I am here to dive into your question with unbridled enthusiasm.

Yes, it's absolutely possible to join dissimilar metals using MIG (Metal Inert Gas) welding. Your approach of interlayering thin metal foils between low carbon steel and aluminum is quite interesting. Let me share some insights and possible outcomes:

1. **Metallurgical Challenges:** Joining dissimilar metals like steel and aluminum can be challenging due to their vastly different melting points and thermal conductivity. However, the use of thin foils and precise control in MIG welding can help mitigate some of these challenges.

2. **Intermetallic Compounds:** When two dissimilar metals are joined, intermetallic compounds may form at the interface. The composition and properties of these compounds can impact the joint's strength and performance. It's essential to carefully study and characterize these compounds.

3. **Possible Outcomes:** The success of your joint will depend on factors like the welding parameters, interlayer material, and the quality of the welding process. If done correctly, you can achieve a strong, reliable joint with acceptable mechanical properties.

4. **Testing:** Once you have your joints, testing is a crucial step. Tensile testing will assess the joint's strength under tension, while fatigue testing will determine its endurance under cyclic loading. These tests will provide valuable data on the joint's performance and durability.

5. **Applications:** If your research yields positive results, the applications could be numerous. Joining dissimilar metals is often required in industries like aerospace, automotive, and construction, where you need lightweight structures with high strength.

Remember, research is all about exploration and discovery. Embrace the challenges, meticulously document your process, and don't shy away from experimentation. Your work could potentially lead to innovative solutions in the field of dissimilar metal welding. Best of luck, and may your research yield exciting outcomes!

Hi Md Marjan Jahan Tazin

Welding aluminium to steel is difficult because the two alloys have different metallurgical and physical properties. They melt at significantly different melting temperatures and possess different thermal conductivity, making joining them hard. In addition, the two alloys are almost insoluble in each other. In a molten state, they react and form brittle intermetallic phases making them hard to join when welding. The resulting weld can be too brittle and inappropriate for most applications. Therefore, the welding of thin aluminium foil layers on steel by using conventional welding techniques, such as arc welding, MIG welding, or TIG welding, will result in the formation of brittle iron-aluminium intermetallic phases at the joint and you will end up with a weak weld joint.

However, it is still possible to weld steel to aluminium but you have to use bimetallic transition inserts welding in which inserts of already joined aluminium and steel are used to weld the steel and aluminium components together, see the link: https://spurind.com/bimetal-weld-transitions

The use of the bimetallic inserts will avoid melting steel and aluminium together, as the aluminium component is welded to the aluminium side of the bimetallic insert and the steel component is welded to the steel part of the bimetallic insert and a strong welded joint is created.

Also, you could use hot dip-coating process for welding aluminium on steels, in which steel is dipped into molten aluminium to coat it completely. Then the aluminium component is welded to the aluminium coating. In this way, the aluminium doesn’t get in contact with steel during the welding process and the formation of brittle phases is avoided. Dip coating, however is not used for structural applications, but only used for seam sealing.

Hope this helps,

Kind regards

Hi Tazin,

This is a quite obvious question when you start working in such a challenging domain. I had such a dilemma too when I started working on SS-Al dissimilar joining. But, in regard to your question, my answer is yes, it is possible to join carbon steel to Al via the MIG welding process. However, you have to find a narrow process window to get the perfect joint. This may require some optimization experiments too. There will be two important factors that can help you to develop good quality weld between the MS and Al.

1. Process parameter: In general, I found that the joining between the MS and Al will be governed by the linear heat input at the interface, and it should be less than 100 J/mm (may be in the range of 30-90 J/mm). Moreover, the input power and welding speed used to obtain favorable heat input should be in a lower range. In addition, try to use a high flow rate of argon during deposition (20+ LPM).

2. Interface inclusion: It is pretty sure that the direct joining of Fe and Al is really difficult, and if you join it anyway, it won't give you good mechanical properties. Therefore, you need to pot some additional material at the interface during welding. You can use, Ni, Zn, Mg, or Cu foil for this case. However, some powder inclusion of materials such as Oxides, Carbides, and Nitrides, may also lead to a good quality joint.

In your case, the MS has a good amount of carbon in comparison to the SS, which may impart the formation of Al-Fe-C-based intermetallic and can lead to a good interfacial strength between the two. Just you need to properly optimize the process variables for the welding process. I will suggest you perform a suitable literature review around this domain and get some theoretical learning before conducting the experiment.

Good Luck

Amrit