What is the Hardest Metal to Weld?

What is the hardest metal to weld?

Whether you are a welder, project manager or someone searching for a welding service, you may be wondering if the metal you are looking at can easily be welded, without a problem. There are many different tools, tactics and techniques to get the job done, but what welding job is going to bring the most trouble? That would be aluminum! Because of aluminum’s low melting point, it can be challenging for welders to work with. This type of metal can surprisingly bring lots of frustration for various reasons. Here’s why:

 Oxidation and Melting Point

 Aluminum has a natural non-corrosive property, making the welding process a bit trickier than other types of metal. Aluminum oxide is created by exposure to air and water and actually sits as a top layer of the metal, causing the metal to oxidize and corrode quicker than others. This means that there will need to be a higher level of heat applied to the metal to get through that first layer. However, this can lead to unwanted holes in the aluminum underneath – so there is a very short window of workability with this metal. 

 Poor Heat Conductor and Fusion Region

 Since aluminum is a poor heat conductor, it is more difficult to absorb heat during the welding process. This makes it hard to maintain a uniform temperature throughout the joint, resulting in a potential crack or other defects in the final product. Another issue with aluminum being a poor heat conductor is the ability to form one solid piece with two pieces. When you try to melt multiple pieces at once, it can be a challenge to get enough molten material for them to connect properly. 


 As you can probably tell, aluminum is a very sensitive metal and requires extra care and attention to detail. To keep from unwanted impurities such as contamination and oxidation, there are a few easy steps that you can take: 

  • Thoroughly clean the metal to remove impurities and the oxidation layer
  • Make sure you store the metal correctly right away to avoid any future contamination 
  • Keep the aluminum at room temperature to prevent oxidation 

 While aluminum is a difficult metal to weld, it is not impossible. Taking a few extra steps such as cleaning and properly storing the metal, can help to reduce any unnecessary trouble beforehand. At nexAir, we want our customers and employees to be properly educated, trained and equipped with everything they need to Forge Forward. Please lean on our applied industry KnowHow, and give us a call with any questions that you may have. Thank you for choosing nexAir for all of your welding and gas needs!


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