Difference between AC and DC Welding – The Ultimate Comparison

Welding is the process of joining two metallic parts together. Due to high heat generation during the process, the metal melts and joins together after cooling.

To generate this much heat, various energy sources are used. Welding can be done by laser or ultrasonic method. Oxy-acetylene flame is also used. But the most popular method is to use electricity.

Based on which type of electricity or current we are using, welding can be divided into two types, AC welding, and DC welding. But what are the differences between Ac and DC welding?

This is the topic I’m going to discuss here. I’ll be covering AC vs DC welding from every perspective. So, let’s start.

Table of Contents

AC Vs DC welding

As I said, the classification is based on the type of current we are using. If you know what AC and DC currents are, you will easily understand AC and DC welding machine differences too.

AC means alternating current. This is the currency we use for most household electronics. Ont the other hand DC means direct current. We use it for charging regular devices.

While welding we can use any of these current if we have the proper setup. Based on which currency is being used, the welding machine and the process are named. If you have the whole idea about these two processes, you can easily identify the AC and DC welding differences.

What are the differences between Ac and DC welding?

Topic	AC welding	DC welding
Power Source	AC welding can be done with high voltage alternating current (AC)	Direct current is used as the power source of DC welding
Primary Advantage	Ac welding provides more flexibility in controlling the arc blow	DC welding arc is stable and provides a smooth area after welding
Primary Drawback	The arc of AC welding is not stable as the current itself fluctuates every second	Controlling arc blow is not as easy as AC welding
Where to use	For heavy metal or joining Aluminum, AC welding is preferable	For sheet metals, and thin plates joining, Dc welding is considered the best method
Where to avoid	AC welding is not suitable for thin metal as it will melt the metal and the whole process will be dismissed	DC welding is not good for the heavy-duty metal joining process. Also, joining aluminum by DC welding can create problems due to oxidation.

What is AC welding?

AC welding means doing the welding job by using an alternating current. AC welding reverses its direction every second. A 60 Hz AC means, it will change its phase 120 times from negative to positive in one second.

Due to this fluctuation, the net deflection is not certain. This is because the magnetic field and the current both are changing their direction in every second.

With AC welding high heat can be generated. This process is used for some special cases. Later I’ll discuss these.

Where is AC welding used?

AC welding can produce an enormous amount of heat. That’s why this process is used for welding heavy metals. AC welding is widely used in the machines and shipbuilding industries.

One of the best uses of this process is joining magnetic metals. Which you can’t do with DC welding. The blow of arc is better. For the welding of aluminum, AC welding is a preferable option.

Advantages of AC welding

Here I’m mentioning some pros of AC welding. Let’s take a look,

The arc blow is more controllable.
The positive and negative phase changing allows for the removal of oxides from aluminum. That’s it’s more convenient for welding this metal with AC welding.
Power consumption is comparatively lower than DC welding.
The welding process generates less noise than DC welding. The cost of AC welding is also lower than DC.
The setup of AC welding is lighter than DC welding and thus requires less space.

Disadvantages of AC welding

Well, there are some disadvantages too. That’s why AC welding is not that much used. Let’s see why

The stability of the arc of AC welding is not good enough.
The welding quality is not well and doesn’t provide a smooth surface. It doesn’t give an aesthetic look over the welding area.
The handling process is a bit harder than DC welding and needs high skill and experience.

What is DC welding?

If you have read the AC welding part well and understood the mechanism, you should already have an idea about the DC welding process.

DC welding is nothing but a similar welding process to before except DC or direct current is used as the power source. Direct current flows in a constant direction and that’s why the arc is more stable.

This process is most widely used. In the following part, I’ll discuss where DC welding is used.

Where is DC welding used?

Dc welding is used for most welding processes. Where the parts that need to be welded are situated overhead or in vertical positions, DC welding is considered the best option.

Most joining processes, use DC welding as the method. Methods like TIG, MIG, and sheet metal welding are done by using DC welding too.

Advantages of DC welding

The advantages of DC welding are more than AC welding. That’s why this process is more popular even though it needs a heavier setup. Let’s see some of those.

DC welding generates a stable arc which is excellent for smooth welding operations. By using DC welding, expert welders can generate smooth joined surfaces. That’s why it is used for places where aesthetics are necessary.
For thin metals like the joining of sheets, metals need DC welding. It can’t be by AC as it will melt the sheet with its high heat. That’s why DC is preferred.

Disadvantages of DC welding

Though DC welding is easier to handle and more widely used, this process has some cons too. Here I’m mentioning some of those below.

DC welding needs a heavier setup and the maintenance cost is also higher. The required space for this process is comparatively larger than AC welding.

DC welding generates more noise than AC welding. This is one of the basic differences between AC and DC welding.

Frequently Asked Questions

AC or DC welding: which one is better?

DC welding is more popular for performance while AC welding is used for special purposes.

Does AC welding cost less than DC welding?

The initial cost of AC welding is less than DC welding.

What do AC and DC mean?

AC stands for Alternating current and Dc stands for direct current.

Which one is easy: AC or DC welding?

DC welding is comparatively easier than AC welding when it comes to handling.

Conclusion

Welding is highly used in each and every industry, and construction site. The various environmental condition needs different welding processes.

But except for gas welding, most welding uses electricity as the power source. So, based on the electricity, the process can be divided into two types named AC and DC welding. And if you compare AC vs DC welding, this is the basic answer. There are different Ac and DC welding machines too.

For joining magnetic parts or aluminum, AC welding is better. But for light and thick parts, DC welding does better performance. However, for any of these processes, a highly skilled welder is needed. Otherwise, both the job and the person can be harmed.