Difference between AC and DC welding, Pros and Cons

Welding is a versatile and complex procedure, and welding machines use both gas and electricity as fuel. In this post, you are going to learn the difference between AC and DC welding. Basically, the AC and DC are two types of currents welding machines take to produce an electric arc.

The arc that emerged from the metal electrode is extremely hot, which is exceptional for fusing two metals. So it’s clear that both AC and DC are intended for arc generation, but the difference is the polarity of the electric current. However, the electrode’s polarity has a significant impact on the integrity of welds; thus, it is wise to choose between dc and ac welder correctly.

Generally, the DC polarity flows in one direction, so it is known as a straight flow because of its constant nature. Moreover, the AC polarity flows in both directions; therefore, it is called reverse flowing. That’s why it is crucial to have a proper understanding of ac vs. dc welder. In this way, you create smooth and seamless, and total joints.


What is meant by DC welding?

In DC welding, electrons flow from the electrode in one way continuously. Moreover, the polarity remains steady DC welding, which may be positive or negative. Therefore, it is suitable for those appliances with low voltage, like phone batteries and remote controls.

Most of the welding applications demand DC polarity because it creates smoother and fuller welds than AC. Besides, it creates a much stable arc, which is excellent for deep penetration and better productivity.

As mentioned before, DC polarity is of two types negative and positive. You can use DC negative for welding thin metals with wicker deposition rates. Further, DC positive polarity is ideal for welding thick metals or when deep penetration is necessary.

Related: Aluminum TIG welding with DC

Applications of DC welding

There are various known applications of DC welding, one of which is that it is remarkably compatible with a stick welder. You can use direct current welding on steel which requires more heat and deeper penetration. In addition to this DC, welding is perfect for single carbon brazing.

The benefits of direct current welding are the following:

  • Clearer welding output than AC
  • Fewer bubbles in joints
  • Much stable arc
  • -ve polarity is exceptional for thin metal welding
  • +ve polarity is incredible for thick metal welding

The disadvantages of direct current welding are the following:

  • Arc blow issues are unfixable
  • DC welding machines are pricey
  • It’s not suitable for aluminum welding

What is meant by AC welding?

Unlike DC welding, electrons in this form of welding go backward and forward. Moreover, in one second, AC welding changes its polarity 120 times. Whenever polarity shifts from DC -ve to DC +ve, the output has 0 amperage, which results in the extinction of the arc.

If you want to reduce this issue, you should use those electrodes made for AC welding. But the arc still is very volatile than DC welding. Alternating current is exceptional for transferring electric current over considerable distances. So, AC is ideal for high voltage appliances like home use electronics.

Generally, AC is not the first choice when it comes to welding because of its less heat, and the arc can’t go inside into the metals. But this nature of AC welding makes it ideal on a few occasions where you need to create welds on thin metal or low melting points.

The advantages of alternating current welding are the following:

  • It clear oxides incredible when welding metals with oxidized surface
  • Excellent for welding aluminum
  • When the alloys to be welded, they have a magnetic effect
  • Provides excellent welding of plates in shipbuilding

The drawbacks of alternating current welding are the following:

  • Welds created have a lot of spatter
  • The smoothness of welds is not comparable to DC welding
  • Arc handling is difficult and not reliable

Which electrode should you use?

For DC welding

The 6010 electrode is brilliant for DC welding because it is designed especially for that purpose. Moreover, the cellulose-sodium covering is of higher content. Besides, this electrode enables you to take the arc deeper into the metal and has various uses in the field.

For AC welding

As we know, in AC, the welding arc is suddenly defunct and then comes back. That’s why special electrodes are made for this job which has a unique covering including 6011, 6013, 7018, 7024. Moreover, these electrodes enable the arc to ignite in windy conditions and provide tinier penetration.


Both AC and DC welding techniques are performed to accomplish welding tasks. Therefore, both of them have their pros and cons. If you want to create smooth welds, then it is better to gain knowledge about which procedure you need to apply in a particular work. Moreover, safety procedures are a must to follow no matter which method you are applying to create welds.