AC vs DC welding – Main Differences and Applications

Why do welders prefer DC? What are the main differences between AC and DC welding? Which one should I use? – These are some common questions you might have if you are getting into the art of welding.

The difference between AC and DC current determines the nature of these two types of welding. Below is a thorough comparison of the two and a detailed conclusion on which one you should use under what circumstances:

Definition

Before heading into the definition of the two, let’s understand AC and DC power. AC stands for Alternating Current that changes direction or alternates between positive and negative. The regular electricity that we use in our household from power outlets is AC power.

On the other hand, DC or Direct Current, as the name implies, is linear and travels straight. Examples of DC power are batteries, fuel cells, solar panels, etc. You can also convert AC into DC. Now, let’s look at the definitions of AC and DC welding.

AC Welding

The welding procedure which uses AC as its electric power can be called AC welding. The current used for such welding alternates instead of having a direct path. Imagine a wavy line; that is a good representation of this type of electric current.

DC Welding

When direct current is used for welding, it is simply DC welding. A steady stream of electric power is received in the electrode, which helps welding materials. You can use DC welding in both positive and negative polarity.

Basics

The primary factor differentiating both types of welding is polarity. Electric circuits consist of negative and positive poles. Direct current has a constant polarity while AC power changes direction and is completely opposite of DC power.

This change of direction between positive and negative makes the AC welding inferior. DC is the preferred electric power for most welding tasks, and welding devices are usually used with direct current.

Advantages and Disadvantages

Even though DC seems to be superior for welding in most cases, specific works require AC power. Each has its own pros and cons.

DC Welding Pros

DC Welding Cons

AC Welding Pros

AC Welding Cons

Applications

Most of the stick welding tasks require you to use direct current. Moreover, if you are working with thin materials, DC is the preferred option. Vehicles, furniture, and anything where aesthetics are involved, DC can provide a clean weld!

Professionals who are looking for precise welds and good finish use DC even though it is the more expensive option. Its superiority makes it highly applicable in most weld tasks.

For welding aluminum, AC is the better option as it can take out oxide from metallic surfaces. That’s why AC welders are used for TIG aluminum welding.

AC welds are also faster and used in making ships and heavy plates. Moreover, professionals prefer alternating current for repair tasks and welds that do not require much aesthetic value. Hobbyist welders prefer AC because it is cheaper and can provide a faster filling.

Final Note

AC and DC power have their specific usage in welding. It is better to get a quality welder that can be suitable for both types of welding. Even though they are a little more expensive, they are surely worth it, as most professionals would agree.

So, depending on what kind of welding tasks you will be doing, you can choose the right welder according to AC or DC power.