What’s the Difference Between Ac and Dc Welding?

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Arc welding is a welding process that is used to join metal to metal by using electricity. The electricity is used to create enough heat for the metals to both melt together. The power supply can either be direct (DC) or alternating (AC) current.

These currents can’t just be picked at random as sometimes they can cause problems in welding. Here’s the differences between DC and AC currents.

Direct Current

Direct current is when the electricity flows in a constant direction and can possess a voltage with a constant polarity. The typical direct current includes the current in batteries and is often used in low voltage devices. Low voltage devices are typically mobile phones, tablets and TV remote controls.

A negative electrode, the direct current, provides a faster deposition rate compared to an alternating current because there is a quicker melt-off of the electrode. Alternatively, an AC current provides deeper penetration.

DC Welding is ideal for:
• Overhead or Vertical welding
• Single carbon brazing
• Stainless steel; TIG welding

Alternating Current

In welding, an alternating current is electricity that switches direction and so, the voltage periodically reverses because of this switch. You would typically find an alternating current from your electrical outlets in your house or for household appliances like fridges, TVs and ovens.
An alternating current changes its polarity several times per second and because of this, it results in deeper penetration. The main advantage of AC welding is that it allows the weld operator to weld on magnetic metals.

AC Welding is ideal for:
• Aluminium TIG welding with high frequency
• Downhand heavy plate
• Fast fill

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