TYPES OF ARC WELDING & HOW IT WORKS - ULTIMATE GUIDE

What Is Arc Welding?​

Like other fusion welding processes, arc welding is used to join metals. Arc welding does this by using an electric arc that creates an intense amount of heat, which melts metals and allows them to join together.

A power source is used to create this arc between an electrode and the base material, which melts them at the point of contact. Arc welding can use either a direct current (DC) or an alternating current (AC) in the process.

How Does Arc Welding Work?​

The power generated in the arc welding process comes from either an AC or DC power supply. This creates a high amount of heat — around 6,500 degrees Fahrenheit! — which is needed to melt the base materials.

The arc then gets formed between the work piece and electrode, which can either be a rod or wire that is guided along the joint connecting them. This can be guided either manually or mechanically.

Equipment Used in Arc Welding​

A variety of equipment is used in the process of arc welding, including:

• Welding machine: Provides the power supply used for generating the heat necessary to the welding process.
• Electrode holders: They ensure electrodes are kept at a desired angle.
• Cables or leads: They carry current from the machine to the work.
• Cable connectors: Make a connection between machine switches and the electrode holder.
• Chipping hammer and wire brushes: Both are used to remove remaining particles or materials produced as a byproduct of the welding process.
• Protective clothing and face shield: Ultraviolet and infrared radiation is produced when welding, as well as sparks and heat. Protective clothing is worn, as well as a screen or shield to protect the eyes and face.

There are four main types of arc welding, all of which are taught in the welding program at Universal Technical Institute (UTI). They are:

• Gas Metal Arc (GMAW)
• Shielded Metal Arc (SMAW)
• Flux-Cored Arc (FCAW)
• Gas Tungsten Arc (GTAW)

Brian Masumoto, welding instructor at UTI Rancho Cucamonga, says UTI stands out when compared with most welding programs that concentrate on a specific process.

“Our experience isn’t limited to just one type of welding,” Masumoto says. “We cover all the major types of welding, which better prepares students for all different types of industries. We don’t focus on just one process. The students learn and experience the different processes, which makes them better qualified for a job.”⁶

Let's take a closer look at the four main arc welding processes and how these different kinds of welding help keep the world running.

Gas Metal Arc Welding: GMAW

Gas metal arc welding (GMAW), also known as metal inert gas (MIG) welding, uses a continuous solid wire electrode that travels through the welding gun, which is accompanied by a shielding gas to protect it from contaminants.

GMAW is one of the most common welding processes and can be used indoors to weld materials for industries like construction, vehicle production, manufacturing and aerospace. It’s not recommended to use GMAW outdoors, since the wind can blow away the gas and damage the process.

GMAW welding produces minimal waste and isn’t prone to chipping. The process can be semi-automatic or fully automatic, which makes it simpler for welders because they don’t have to worry about defects on stops and starts.

Shielded Metal Arc Welding: SMAW

Shielded metal arc welding (SMAW) is a welding technique that can be used on all ferrous materials in all welding positions. Another name for SMAW is stick welding. A flux-coated electrode (which is a metal stick in an electrode holder) is connected to a power source and touches the base metal to produce the weld. The flux shields the electric arc to prevent contamination.

SMAW can be used to weld low- and high-alloy steels, carbon steel, cast iron and nickel alloys for industries like construction, shipbuilding and manufacturing. It can be done indoors and outdoors.

SMAW produces slag, which is a layer of byproduct welders chip off after the weld for a clean look.

Flux-Cored Arc Welding: FCAW

Flux-cored arc welding (FCAW) uses a continuous hollow wire electrode with a flux compound that protects the weld pool by forming a gas. FCAW is ideal for outdoor welding and for welding on dirty or contaminated materials, since it doesn’t require an external shielding gas to protect the weld from atmospheric elements. Much like the SMAW process, FCAW also produces slag that is chipped off after the weld to give it a clean look.

FCAW is often used for thick materials because the flux-core wire can penetrate thick weld joints. FCAW isn’t appropriate for materials that are thinner than 20 gauge.

FCAW can be used on cast iron, stainless steel, carbon steel, high-nickel alloys and low-alloy steel. This welding technique is used in industries like construction and shipbuilding.

Gas Tungsten Arc Welding: GTAW

Gas tungsten arc welding (GTAW) is also known as TIG welding, which stands for tungsten inert gas. Just like in GMAW welding, an inert shielding gas is used. But unlike GMAW, which uses a wire that also acts as filler material, GTAW heats up objects by utilizing a tungsten electrode that delivers current to the welding arc. This welding arc melts the metal and creates a liquid pool. Filler rod can then be added if necessary to enhance the strength of the weld.

GTAW requires great precision, since the tungsten needs to avoid touching the work piece and materials can’t be overheated, otherwise cracks and other issues can occur. The benefits of GTAW include greater weld control and improved strength and quality of welds.

GTAW also results in chip-free welds for a clean look. It is most commonly used to weld thin material and can be used for ferrous or nonferrous metals like stainless steel, aluminum, copper, magnesium and titanium.

Learn All About Welding at UTI

At UTI, students get to work with high-quality welding tools they’d use in the professional world. Supportive instructors are there to answer questions and provide guidance. Students can graduate from the program in just 36 weeks.

Learn more about the UTI Welding program. Contact us for information.