How Hot is a Welding Arc? (6 Safety Precaution Tips)

How hot is a welding arc? Typically, arc welding temperatures can range from 3,000 to 6,500 ºF (1600 to 3600 °C). However, plasma arc welding reaches a temperature of 45,000 ºF (25,000 °C) or higher.

The arc temperature varies depending on the metal type, welding mechanism, and gas used. The output voltage, current, and the arc’s length can also impact how hot the welding arc gets.

In this article, I’ll discuss how a welding arc operates and the temperature range of different types of welding. I’ll also guide you through six welding safety precaution tips.

How hot is a welding arc

Temperatures of Different Types of Welding

There are two types of arc welding: consumable (fusible) and non-consumable (non-fusible) arc welding. The former uses a rod that melts to become part of the weld, while the latter doesn’t.

Shielded metal, gas metal, and flux-cored are all examples of fusible arc welding. Conversely, gas tungsten arc welding and plasma arc welding belong to the non-fusible category. 

Let’s discuss the temperature range of each welding type and its uses in detail.

Shielded Metal Arc Welding (SMAW)

Most shielded metal arc welding rods can reach a temperature of 11,000ºF. That impressive thermal energy makes SMAW one of the most common types of arc welding. Plus, you can do SMAW indoors or outdoors!

You can use it to weld 1/8-inch-thick metals. Still, this non-consumable welding type can work for thicker rods.

Examples of common metals SMAW can weld include:

  • Carbon steel
  • Low-alloy steels
  • High-alloy steels
  • Cast iron
  • Nickel alloys

Gas Metal Arc Welding (GMAW)

Gas metal arc welding typically reaches a temperature of 3,000ºF

As the name implies, this arc welding type uses gas to protect the melted metal from atmospheric contamination. On that note, the gas used separates GMAW into two types, metal inert gas (MIG) and metal active gas (MAG). 

Both types of arc welds are common for indoor welding activities. That’s because outside air can blow the protective gas away. As a result, the welding process might not be successful.

You can use MIG and MAG for rod thicknesses between 1/8 and 3/4 inches.

That said, avoid using MAG welding for light steels and alloy metals—but why? This type of arc welding uses active gases like carbon dioxide. Once heated to 1300ºF or higher, carbon dioxide gas splits into carbon monoxide and oxygen.

As a result, the released oxygen can partially oxidize the iron alloys, causing rust.

Common areas that use GMAW include:

  • Pipe joint welding
  • Indoor construction
  • Automotives 
  • Railroad tracks

Flux-Cored Arc Welding (FCAW)

In general, flux-cored arc welding can have a temperature of 6,500ºF. The arc can even reach high temperatures up to 10,000ºF. A perk that makes it work well for numerous metals, like cast iron, carbon steel, and stainless steel.

Because FCAW usually doesn’t use gas shielding, it’s ideal for outdoor welding. It can even weld contaminated and dirty materials!

What’s more, this flux-filled welding arc works well on thick metal joints! However, it’s not your best option for materials with a thickness of less than 20 gauge. 

Industries that commonly use FCAW include construction and shipbuilding.

Gas Tungsten Arc Welding (GTAW)

Gas tungsten arc welding, or TIG welding, uses a non-consumable metal arc. So, you’ll need to use a filler rod with TIG welding. 

TIG welding can reach a temperature of 6,000ºF thanks to tungsten’s high melting point, which is about 6,191ºF. 

Unlike other welding types, GTAW requires precision skills. That’s because the entire welding process is manual. You’ll need to ensure the tungsten doesn’t touch the welding pool or overheat it. Plus, you have to feed the filler rod into the joint yourself.

How is the Heat Produced?

Most welding arcs operate through a power supply, an electrode, and a shielding component.

The power supply uses electricity from direct or alternative currents to generate heat. As a result, the metal electrode at the tip of a welding gun becomes hot. The metal electrode reaches high enough temperatures to melt the welded rod.

Alternatively, some welding arcs melt, so you don’t have to worry about using external rods.

As mentioned earlier, a barrier component, like active or inert gasses, is vital to protecting the welding area from atmospheric air. Instead of gas, some welding arcs use flux. 

Protecting Yourself from the Heat

Here are a few tips to protect yourself from welding heat:

  1. Always wear protective gear, like a flame-proof helmet, face shield, protective goggles, a heat-resistant jacket, welding gloves, and boots.
  2. Work in well-ventilated areas, especially when working with hazardous metals.
  3. Only work on concrete floors or other flame-resistant materials to prevent fires. Plus, keep an extinguisher nearby.
  4. Double-check that you’ve installed the welding machine properly.
  5. Make sure your electrical system meets the electricity requirements of the welding machine.
  6. Always use an insulating mat when welding conductive metals to prevent electric shock.

Conclusion

So, how hot is a welding arc?

The temperature an arc reaches depends on the type of arc welding used. Gas metal arc welding has the lowest temperature of 3,000ºF. Other consumable welding arcs like flux-cored and shielded metal can reach high temperatures up to 10,000ºF and 11,000ºF, respectively.

Non-consumable welding arcs like gas tungsten have a temperature of 6,000ºF, while plasma arc reaches a whopping 50,000ºF.

Whichever welding arc type you use, make sure to wear protective equipment. Plus, always work in well-ventilated, fire- and electrical-safe areas to prevent potentially hazardous situations.