Today, the unique characteristics of aluminum are lightweight, high strength, extreme temperature capability, the versatility of extruding, recycling capabilities, and excellent corrosion resistance that make it the obvious choice of material by designers and engineers for a variety of welding fabrication applications.

Aluminum is readily joined by brazing, welding, and soldering.

Welding aluminum requires different shielding gases, different specifications, different welding techniques, and different pre-weld and post-weld processing than welding steel. Aluminum can be welded easily, but first and foremost, the right welding process must be selected.

What type of welding is used for the aluminum?

The following are welding processes that can be used for aluminum:

● TIG

● MIG

● Electron Beam welding and laser beam welding

● Resistance Welding

TIG:

One of the most well-known welding processes for aluminum is gas tungsten arc welding (GTAW); otherwise, it is known as inert tungsten gas (TIG) welding. GTAW is a popular process for aluminum because it does not make necessary mechanical wire feeding, which can build feed ability issues. Also, the GTAW process is extremely clean and clear, which helps to prevent aluminum from being contaminated by the atmosphere.

MIG:

Metal inert gas (MIG) welding or Gas metal arc welding (GMAW) is another great choice for welding aluminum. Gas metal arc welding has higher deposition rates and faster travel speeds than GTAW. However, GMAW uses the mechanical wire feeding system.

Because of this, a spool gun or push-pull gun may be needed so that this aluminum wire feeding is possible. Also, it is important not to use 100% CO2 or 75% Argon or 25% C02 shielding gas. Such gas is an effective choice for steel, but aluminum cannot handle the reaction of C02 gas. Follow the manufacturer recommendations for shielding gas type.

Laser Beam Welding and Electron Beam Welding:

Beam welding processes are quite capable of welding aluminum. Since the power density of the beam welding processes are so high that the cold starts are less of a concern. With laser welding, the material of light reflectivity can be a concern. Shielding gas optimization is the key to avoid porosity. Electron beam welding does not have these problems because it does not use the light as an energy medium, and it is performed in a vacuum medium.

Resistance Welding:

Resistance welding is the connection of metals by passing current and applying pressure for a length of time through the metal area, which is to be joined. The key advantage of this welding is that no other materials are needed to create the bond.

That's why it makes this process extremely cost-effective.

What is the best method to weld aluminum?

Metal inert gas (MIG) welding can be used successfully to weld the aluminum. At the time of selecting a welder, it must be decided whether pulse welding or spray arc welding methods will be used. Pulse welding requires an inverter to supply the power, while constant voltage and constant current machines can be used for spray arc welding. MIG welding is the best for thinner gauges of the aluminum sheets because of the amount of heat needed. At the time of choosing a shielding gas, 100 percent argon is the best for MIG welding aluminum. The welder must choose a welding rod or wire that has an alloy as similar to that of the workpieces as possible to make a quality weld.

Installation technique of aluminum welding

How to MIG Weld Aluminium

Strike a clean and clear welding electrode around an inch from the start of the weld, then quickly move it over the point where you need to start welding.

You can use a string bead technique which helps to move along the weld, but be careful not to change the angle of an electrode as you proceed. You should be moving quickly anyway, but as you near the end of the weld, try to improve the speed. It will taper off the size of the weld pool, and in turn, decrease the amount of cracking.

It is a better idea to point the gun in an upwards direction when you are welding in the horizontal direction.

How to TIG Weld Aluminium

TIG welding will need you to use both hands, so be sure that you are wearing a suitable pair of a welding helmet and welding safety gloves to protect yourself while keeping your hands free. In your one hand, you will be holding the electrode holder, while the filler rod will be held in your other hand.

With lift start and scratch start techniques, there is a risk of some of the tungsten from the electrode will be left to start behind on the metal, contaminating the weld. So to avoid this, form an arc on a scratch block to heat up the electrode, before starting and breaking the arc again on your weld joint.

Slowly moving forwards and backward a little the whole way, move along the joint, ensuring that your electrode and filler rod never touch.

Once you lastly reach the end of your weld, if you break off the arc suddenly, you will end up with cracked and defective welds. So, you can avoid this problem by reducing the current towards the end, which is easy to do if you use afoot to control.

How to Weld Aluminium to Steel

Aluminum is a relatively lightweight metal, soft, thin, while steel is much heavier, tougher, and thicker, so joining the two can be difficult.

Generally, there are two easy methods for welding aluminum to steel, although both need more time to work than ordinary welding.

Alternatively, you could try coating the steel in silver solder or dip coating the steel with aluminum. These techniques are expensive and also require the other challenging skill set, but they do make it easier to weld pieces of the steel to aluminum.

Conclusion:

You should be able to see that aluminum welding presents more challenges than welding steel or other metals. However, the extra practice and expense on the equipment will pay off; as a result, it will look really professional. Aluminum is a perfect material to work with, so it is a must-have skill for anyone who takes the welding seriously.