WELDING TYPES: ARC WELDING GUIDE

What Is Arc Welding?​ 

Like other welding types and 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 fuse 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. 

History and development of arc welding 

The history and development of arc welding trace to the late 19th century, when advances in electricity and metallurgy paved the way for this groundbreaking technique. Arc welding, which uses an electric arc to melt and join metals, was first introduced in the 1880s by Russian inventor Nikolai Benardos. Over the decades, advancements like the introduction of coated electrodes in the early 20th century improved the process’s efficiency and quality. By World War II, arc welding had become a critical technique for shipbuilding and manufacturing due to its speed and ability to create strong, reliable joints. Today, arc welding has evolved into various specialized processes, including MIG, TIG, stick and flux-cored arc welding, which are widely taught in professional programs like those offered by Universal Technical Institute (UTI).¹ 

Importance of arc welding in modern industries 

Arc welding is essential to modern industries due to its versatility, efficiency and ability to create strong, durable joints. It supports various welding types where joining metal components is vital for producing buildings, bridges, vehicles and machinery. Arc welding encompasses different kinds of welding, including MIG, TIG, stick and flux-cored arc welding, making it adaptable to various applications, from precision welding in aerospace to heavy-duty pipeline construction. These types of welds are taught in professional programs like those at UTI, equipping graduates with the skills needed to meet industry demands. The ability to perform different kinds of welding ensures arc welding remains an important part of modern industries. 

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 hot enough to melt the base materials! To put that into perspective, that's more than twice as hot as lava flowing from a volcano! 

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

The science behind the arc welding process 

The science behind arc welding lies in its ability to use an electric arc to generate intense heat, which melts and fuses metal parts together. The process begins when an electric current flows between the welding electrode and the workpiece, creating an arc that can reach temperatures of up to 10,000 degrees Fahrenheit. This heat melts the base metal and, in some cases, a filler material, which solidifies to form a strong joint as it cools. 

Benefits and limitations of arc welding 

Arc welding offers many benefits, making it one of the most widely used welding types, but it also comes with certain limitations. One of its main advantages is its versatility, as it supports different kinds of welding processes like MIG, TIG, stick and flux-cored arc welding, making it adaptable to a wide range of materials and applications. Arc welding is efficient, cost-effective and capable of producing strong, durable joints in everything from small precision parts to large structural projects. However, it does have limitations, such as requiring significant skill and training to master, as well as potential safety risks like exposure to high heat, ultraviolet radiation and fumes. Certain types of welds, like those used in high-stress or specialized environments, may require advanced techniques or equipment. 

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: Ensure electrodes are kept at the desired angle. 
• Cables or leads:  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:  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. 

Types of Arc Welding 

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

• Gas metal arc welding (GMAW) 
• Shielded metal arc welding (SMAW) 
• Flux-cored arc welding (FCAW) 
• Gas tungsten arc welding (GTAW) 

Brian Masumoto, Welding Instructor at UTI Rancho Cucamonga, says UTI training 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.”¹ 

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, is a process when an electric arc forms between the electrode and metal to melt the metal pieces together. 

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 creates slag, a layer of byproduct that welders remove after welding to achieve a clean finish. 

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. 

Key Differences Between Arc Welding Methods

MIG welding (metal inert gas / GMAW) 

• Ideal for quick, efficient welds on thinner materials. 
• Commonly used in automotive and manufacturing industries. 
• Easier to learn and good for high-speed applications. 

TIG welding (tungsten inert gas / GTAW) 

• Known for precision and clean, high-quality welds. 
• Often used on stainless steel and aluminum. 
• Common in aerospace, art and decorative metalwork. 

Stick welding (shielded metal arc welding / SMAW) 

• Versatile and effective in outdoor or rough environments. 
• Performs well on rusty or dirty surfaces. 
• Suitable for thicker materials like structural steel. 

Flux-cored arc welding (FCAW) 

• Best for heavy-duty applications such as structural or pipeline welding. 
• Works well on thick materials and in high-production settings. 
• Can be used outdoors and in windy conditions due to flux shielding. 

Each arc welding method has unique strengths, making it important to choose based on material type, project requirements, and desired weld quality. 

Essential Tools and Safety Gear

Whether you’re just starting out or deepening your skills in arc welding, having the right tools and protective equipment is critical. In any of the different welding types, safety and precision go hand in hand. Common tools used across various welding types include: 

• Welding machine (MIG, TIG, stick or flux-cored depending on method). 
• Welding helmet with auto-darkening filter. 
• Flame-resistant gloves and jacket. 
• Welding pliers, wire brush and chipping hammer. 
• Angle grinder and clamps. 
• Respirator or proper ventilation setup. 

Because arc welding involves high heat and electrical currents, wearing proper gear helps prevent burns, eye damage and fume inhalation. Regardless of the different types of welds you're performing — whether structural, pipe or sheet metal — staying protected is essential. 

Maintenance Tips for Welding Equipment

Proper maintenance helps ensure safe, efficient welds and extends the life of your tools: 

• Regularly inspect cables, leads and connectors for wear or fraying. 
• Clean your welding helmet lens and replace it if visibility is compromised. 
• Keep your torch and nozzles free of spatter buildup. 
• Store electrodes and filler rods in a dry, clean environment. 
• Check gas hoses and regulators for leaks or damage. 
• Follow manufacturer guidelines for routine servicing of your welding machine. 

Taking care of your equipment not only improves the quality of your welds but also supports safety and consistency across different welding types. Whether you're mastering the basics or exploring advanced arc welding techniques, well-maintained tools are a must. 

Learn About Welding at UTI

At UTI, students get to train with industry-standard welding tools used in the professional world. Supportive instructors are there to answer questions and provide guidance. Students can graduate from the program in just 9-10 months.

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