Arc Welding: What’s the Difference Between AC and DC Welding?
For those who are not experienced welders or do not have any sort of certification, it may be confusing to hear about all of the different types of welding out there. This can commonly include the discussion between AC and DC arc welding. Both of these are valid types of welding, but they have their differences and proper applications. Continue reading below to learn about the primary differences between AC and DC arc welding.
What Do AC and DC Mean?
The bottom line difference between these two welds has to do with polarity. AC means alternating current and DC means direct current. In other words, DC uses a single polarity that could be negative or positive, whereas AC uses an alternating polarity between DC positive and DC negative. There are certain benefits to both types of welding and it takes different equipment to produce each one.
Advantages and Disadvantages of DC Welding
DC welding is the preferred form of welding for most applications. Compared to AC welding, DC tends to have a smoother welding output, less spatter, and a more stable arc. It also penetrates more into weld metal, which offers a stronger bond than AC welding in most cases. Unfortunately, DC welding is not great for welding aluminum because it cannot produce the right heat. In addition, it cannot fix arc blow back issues, which occur when the arc wanders or goes out of the joint. Furthermore, when it comes to purchasing a welder, DC equipment is more expensive because it needs an internal transformer to switch the current.
Advantages and Disadvantages of AC Welding
Several of the disadvantages of DC welding are actually where AC welding tends to shine. It supports higher temperature welding, which makes it a great option for welding aluminum and removing the oxide film on the metal. It can also fix issues involving arc blow, and the alternating current makes it steadier when welding materials that are magnetic. Since AC welding does not require an internal transformer like DC welders, AC welders are less expensive, which can make it a better option for beginners. Conversely, AC welding falters in the areas of DC welding’s strengths, as well as a couple other areas. It is harder to control and less reliable than DC welding, is not as smooth, and tends to have more spatter.
Is AC or DC Welding Better?
DC welding tends to be the preferred option for most applications. However, for certain applications or metals, AC welding can be the better choice. For home or beginner use, it really comes down to what needs to be done, but AC welders are cheaper. Price can make them a better option for arc welders who want to get used to the basics and learn to weld or complete smaller jobs before investing in a more expensive DC welder.
The other factor to consider is the power that is drawn by the welder. AC welders are more versatile because they can be used on outlets that are limited to 110 volts. In contrast, DC welders require more power and a special outlet will need to be wired in the home or shop to provide 220 volts. This can be a significant investment, so it is recommended to gain more experience with welding before jumping right to more expensive DC welders.