Are you thinking of welding some aluminum metal stuff? So, before you spend some money to buy the required stuff, we can help you understand how hard it is to weld Aluminum. So, before we start our journey, it is essential to ease your tension.
Many people will say that welding aluminum is hard, but what they do not know is the procedure; you cannot weld Aluminum like you weld iron or steel. There is a different method, which makes the welding hard.
Why Aluminum is essential?
You must have seen that most of the metal-bodied things around you are made up of Aluminum. The coda can and the watches you wear. There are no limits; we cannot even think of manufacturing cars if there are no aluminum sheets.
Several reasons make Aluminum one of the favorite metals for industries and manufacturers. The Aluminum metal is lightweight, malleable, and can be changed into any form without expending a lot of energy. It is safe to keep edible things in aluminum containers, that is why when you buy the salmon or beans, they are in Aluminum foils. So, you cannot mark down the limits of its use.
When do we need to weld Aluminum?
Several reasons may make you think that you should weld the Aluminum, for me, it can be an everyday task. I may want to create some creative articles for my art class or any DIY. There can be some industrial motives, but here we will only discuss the part linked to a private welding session.
Challenges in welding Aluminum
The molten Aluminum is a bit different from the solid Aluminum, so it is difficult to weld Aluminum metal. The molten Aluminum can easily trap hydrogen molecules, and when you weld it, they tend to stay in the metal, disturbing its composition.
The thing with Aluminum is the hot cracking that can happen when the metal is not cold enough; in the case of steel welding, there can be cracking even after the solidifying process. The aluminum metal is thermally conductive, so when you heat a part of the aluminum metal, the cold parts will immediately take up all the heat, so there will be a higher risk of temperature differences.
The following are the issues that can make the welding of Aluminum a problematic task.
1. Feed ability
Feed ability is the continuity of feeding the spooled welding plates; for aluminum welding, we go with MIG welding, which is different from steel welding. The steel welding wire is a rigged structure that can handle the welding process from a distance without disturbing the steel structure. In the case of Aluminum, it is a lot different. Aluminum can deform during the feeding procedure, and you may even destroy the product.
So, you need to select the most suitable MIG for welding aluminum. To pick the best MIG feeding system, you should work to gather some knowledge about the feeding process and its compatibility with the Aluminum metal.
Brake setting tension is one of the crucial aspects of feed ability; when you are about to weld aluminum metal, consider the brake setting tensions. It needs to be controlled and decreased while welding to avoid the freewheeling when you spool. Automated or mechanical braking systems are the most advanced and effective things to avoid freewheeling.
Next on the list is the drive rolls; they are the essential part of feeding the gun cable wire. They need to be checked for welding aluminum. The U-shaped drive rolls are the best for Aluminum, as they will keep the wire’s round shape intact.
Now the contacting inlet and outlets are also very important for feeding. You cannot use an outlet or inlet contact tip made up of any other metal except Aluminum or alloy of Aluminum. This way, the welding device’s temperature, and the aluminum wire/sheet will stay the same.
2. The hot start features
It is because of the nature of the metal. You cannot change it, but you can devise ways to minimize its effect. If we compare steel with Aluminum, so the thermal conductivity of Aluminum is far greater than steel; in some cases, when we are welding pure Aluminum allotrope, it is six times greater than steel.
The result will be incomplete fusion, which is rare when you weld the steel or iron metals. The solution to stop this effect is using that equipment that has a hot start feature. Hot start is responsible for increasing the voltage of the welding device, especially when it is started. This abrupt heat and ignition will immediately melt the required part of the aluminum metal.
This feature will allow the user to work differently; you are not bound to use the same voltage throughout the welding; rather, it works like a boom initially, and then it may slow down as per the requirement of the metal and work. You can easily set the period for this fast work, as some automated welding systems are available in the market.
This decrease in the dramatic heat sink can help us save a lot of metal and mold or connect the desired part without difficulty. The purpose of this feature is to reduce the risk of incomplete fusion. The incomplete fusion can even distort the welded and connected part after some time; this is why people think aluminum products cannot last long, especially when welded.
3. Crater fill feature
Do you know that Aluminum can expand twice than the other metals? It sounds cool, but the issue is the solidification and decrease in its volume. When you heat the aluminum metal, it immediately melts down and expense, but it decreases with a 6% decrease in volume when it solidifies.
Crater cracking is a concern when you are welding Aluminum. It can happen when there is no filler left, and you have started the machine. You can either add the filler to fill the crater or use the crater fill feature. Some advanced welding machines come with a carter filler feature to reduce this risk.
Initially, the welders used the reverse travel technique to avoid the termination cracking, or they will increase the travel speed and ultimately reduce the crater side. We use to reduce the crater size by decreasing the weld pool size before shutting out the full arc. Both these methods are a bit tough, and they require special training as well.
This problem can now be resolved with eh advanced welding machines that come with the inbuilt feature of the Crater filler. This feature is designed to stop the weld slowly and gradually; this can only happen by decreasing the weld current. The welders can set a time for this purpose while they are set up for welding the aluminum wires or sheets.
So, we see how a welder can easily weld the aluminum wires or sheets. The reason most people think aluminum welding is challenging is only the difference. Most people are oblivious of these differences, as they fail to understand the metal’s inherent mechanical qualities.
Moreover, as whole societies and training centers have not worked much to train the welders for aluminum welding; thus, it is not a large part of the welding industry. We need some tips, teachers, and an excellent curriculum to teach aluminum welding to workers and engineers.