What Type of Welding Is Used for Aluminum in The Aircraft Industry?

Author: Jonathan Jonas

Aluminum is an ideal metal to use in an aircraft because of its certain properties. Aircraft companies use aluminum to manufacture the different parts of an aircraft. Today, its projecting demand is doubling and aerospace industries will rely on recyclable alloys in the future.

However, aluminum can pose some challenges. You have to select the right aluminum welding technique, filler material, and storage space, and thoroughly clean the base material.

This article will guide you about the challenges of welding aluminum, which alloys are common for aircraft, and what the common methods are for its welding.

Challenges of Aluminum Welding

While aluminum may be a great choice for aircraft parts, it comes with its challenges. Overcoming them is crucial to make them available for the aerospace industry. There are issues with its oxidation, thermal conductivity, melting point, porousness, thickness, and impurities.

The Oxide Layer

The melting point of aluminum is low as compared to steel. It is 660.3? for aluminum, while the melting point of steel is 1370?. Aluminum has an oxide layer thus making its melting point much higher. During the welding process, this oxide layer acts as an insulation that makes it challenging to weld the aluminum. The welders must be careful not to weld holes in the lower aluminums layers.

The Porosity

Aluminum absorbs hydrogen much quicker. It is very soluble in liquid form. But when aluminum solidifies, the hydrogen separates. This can leave bubbles behind and as a result, the final product could have a porous appearance. This can weaken the aluminum.

Impurities

Aluminum can become contaminated. This is usually due to improper storage and long arcs without proper protection. This contamination can affect its strength, ductility, and some welding properties. Hydrogen can also hamper the performance of aluminum by making the welding weaker. Therefore, proper care and storage are important for successful aluminum welding.

Thickness

Working with aluminum means working with the material at different thicknesses. A welder must be experienced enough to weld correctly to avoid damaging the inner material.

Alloy Series Used in Aircrafts

Each type has a four-digit number according to the system of classification from 1xxx to 7xxx.

  1. 1xxx: it is the purest with 99% of aluminum.
  2. 2xxx: is made from copper with aluminum cladding and is used for aircraft fabrication.
  3. 3xxx: is a great starting point for anyone new to welding aluminum with 1.5% manganese.
  4. 4xxx: contains silicon and has a lower melting point.
  5. 5xxx: this series is corrosion resistant but not the strongest.
  6. 6xxx: contain both silicon and magnesium and are strong.
  7. 7xxx: contain zinc and magnesium and are also used in aircraft because of their strength.

The most common aluminum alloy used in an aircraft is 7075. The main alloying material is zinc. This increases its strength for use in its aircrafts parts. It is also corrosion-resistant and is commonly used for wings and fuselages.

Methods To Use For Welding

The most common method used for welding aluminum is Gas Tungsten Arc Welding (GTAW) also known as Tungsten Inert Gas (TIG). This method uses a non-consumable tungsten electrode that saves the process from oxidation and contamination. Though it doesn’t require a wire filler, it is a more complicated process.

Another method used in Gas Metal Arc Welding (GMAW) or Metal Inert Gas (MIG). Is the wire feeding system. Other methods that are used for aluminum welding are laser beams, which use a narrow beam for more concentrated and deep welding. Aluminum welding also uses electron beam welding, resistance welding, and Shielded Metal Arc Welding (SMAW).

Final Words

Proper care is essential to ensure a successful aluminum welding process. This can include wearing safety PPE, covering and protecting the material from oxidation, and being patient with the welding outer surface. As more and more countries invest in aerospace-related projects, the need for aluminum alloys will increase.