What is the Difference Between AC and DC Welding?

Are you someone who has been working in welding? Are you confused between the terms AC and DC? Well, you don’t have to worry because I have got you covered and in this article, I will explain the difference between both the terms. I will also be talking about the advantages and disadvantages of AC and DC welding.

The Difference Between AC and DC Welding

The main difference between AC and DC welding is the flow of polarity, in AC it changes every second , on the other hand in DC welding polarity flows in a single direction.

Since you are already in the business of welding, you do know that welding requires an electric arc that produces the heat required for melting different metals. AC and DC are the types of currents that are used in the process of welding. In the welding process, it is important that there exists a stable flow of current depending on the polarity of the current.

AC and DC are basically polarities of the current that runs through the electrode of the welding machine. AC is the abbreviation of Alternating Current, while DC stands for direct current. The reason why polarity is so important when it comes to welding is that the strength and the quality of the weld are directly proportional to the polarity of the current.

AC Welding

Different types of current have different effects, and different welds are suitable for different welds. When it comes to the Alternating Current or the AC welding, it is a type of current that is used rarely. Therefore, it is said to be a bit inferior to Direct Current welding. AC welding is mostly used for heavy plate welds. Most importantly, AC welding is used specifically for magnetized metals. It is a known fact that only AC welding can be used for magnetized metals.

AC Welding

Furthermore, AC welding allows deeper penetration; and it is also most suitable for higher temperatures. AC welding is most commonly used for repairing machinery, and the reason for that is the fact that most machinery has magnetized metals. However, the directional instability that comes with AC welding is a drawback.

Advantages of AC Welding

  • Fixes issues with arc blow
  • It can be used for aluminum welding

Disadvantages of AC Welding

  • Spatter
  • It does not have a smooth quality

DC Welding

Just like AC welding, DC welding has its own uses, benefits, and drawbacks. There are certain tasks that cannot be accomplished using AC welding. For example, single carbon brazing and vertical welding. The best thing about DC welding is its deposition rate. The deposition rate of the DC welding is much higher as compared to the AC welding.

DC Welding

DC current is more reliable in comparison to the AC current. The electric arc in the case of the DC current remains constant and stable and is thus highly easy to work with. DC welding is best suited for thinner metals. Another interesting thing to note here is that the machinery used for DC welding comes at a cheap cost; however, the DC welding process itself is very expensive.

However, these costs are necessary costs because there is no alternative for welding certain metals, and they can only be weld using the DC current. Another thing that is important to understand is the fact that it can be used on all metals except aluminum. The reason it cannot be used on Aluminium is that it takes high-intensity heat to melt Aluminium, which is not possible with DC current.

Advantages of Using DC Welding

  • Provides a stable arc
  • Less spatter
  • It has a smooth welding output

Disadvantages of Using DC Welding

  • Unable to fix arc issues
  • Is a bit expensive


Is AC or DC better for welding?

Both AC welding and DC welding have their own advantages and disadvantages. DC can be considered a better option because it allows the welding of Aluminium and other metals. However, DC welding is a bit expensive, and you would have to spend more money when using this type of polarity.

Is AC or DC welding safer?

Both types of welding are safe. The safety of the welding process comes down to the person who is performing the process. It is important for the person to be a professional in the field. Necessary precautions and safety measures should be used for safe welding processes.


Being a part of the welding business, you need to know and understand the difference between AC and DC welding. AC and DC are both types of polarities. Both types have their own benefits and drawbacks. While DC welding is expensive, it enables the welding of all sorts of metals, including aluminum which cannot be processed through AC welding. The choice of the type of current actually comes down to the type of metal that needs to be processed and the amount of money you are willing to invest. You can also have a look at the best AC/DC TIG welders in the market.

About Dave Walker

Dave Walker, a professional welder who has been welding from an early age. Now aims to help others by making them learning skills and finding them new opportunities. He has written for many welding blogs and helped many pursue their welding goals by helping them in choosing the best welding tools of the time.

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